CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application nonprovisional and claims priority from
U.S. Provisional Patent Application No. 61/799,971, entitled, "SECURE ELECTRICAL RECEPTACLE," U.S. Provisional Patent Application No.
filed on March 15, 2014 and
61/944,506, entitled, "FRICTIONAL LOCKING RECEPTACLE WITH PROGRAMMABLE RELEASE," filed on February
25, 2014. In addition, this application is a continuation-in-part of and claims priority
to
U.S. Patent Serial No. 13/228,331, entitled, "LOCKING ELECTRICAL RECEPTACLE WITH ELONGATE CLAMPING SURFACES," filed
on September 08, 2011, which is a continuation-in-part of and claims priority to
U.S. Patent Serial No. 12/568,444, entitled, "LOCKING ELECTRICAL RECEPTACLE," filed on September 28, 2009, which in
turn is a continuation-in-part of
U.S. Patent Serial No. 12/531,235, entitled, "LOCKING ELECTRICAL RECEPTACLE," filed on September 14, 2009, which is
the U.S. National Stage of
PCT Application US2008/57149, entitled, "LOCKING ELECTRICAL RECEPTACLE," filed March 14, 2008, which claims priority
from
U.S. Provisional Application No. 60/894,849, entitled, "LOCKING ELECTRICAL RECEPTACLE," filed on March 14, 2007.
U.S. Patent Serial No. 12/568,444 also claims priority from
U.S. Provisional Application Serial No. 61/221,793, filed on July 10, 2009. This application further is a continuation-in-part of and
claims priority to
U.S. Application Serial No. 13/088,234, entitled, "LOCKING ELECTRICAL RECEPTACLE" filed on April 15, 2011, which claims
priority from
U.S. Provisional Application Serial No. 61/324,557, filed April 15, 2010, entitled "LOCKING ELECTRICAL RECEPTACLE SECURE LOCKING MECHANISM;"
U.S. Provisional Application Serial No. 61/346,316, filed May 19, 2010, entitled "LOCKING ELECTRICAL RECEPTACLE ALTERNATE OPERATING MECHANISMS;"
U.S. Provisional Application Serial No. 61/353,496, filed June 10, 2010, entitled "LOCKING ELECTRICAL RECEPTACLE PROGRAMMABLE RELEASE TENSION MECHANISMS..
BACKGROUND
[0002] A wide variety of electrical connectors are known to provide electrical contact between
power supplies and electrical devices. Connectors typically include prong type terminals,
generally referred to as plugs, and female connectors designed for receiving the prong
type terminals, generally referred to as receptacles, often described as electrical
outlets, or simply outlets. The most common types of outlets include a pair of terminal
contacts that receive the prongs of a plug that are coupled to "hot" and "neutral"
conductors. Further, outlets may include a terminal contact that receives a ground
prong of a plug. A variety of standards have been developed for outlets in various
regions of the world.
[0003] Regardless of the standard at issue, the design of the aforementioned most common
plug and receptacle system generally incorporates a friction only between metallic
contacts means of securing the two in the mated position. The frictional coefficient
varies depending on a variety of conditions, including, but not limited to, manufacturing
processes, foreign materials acting as lubricants, and wear and distortion of the
assemblies. This characteristic results in a non-secure means of interconnecting power
between two devices. It is arguably the weakest link in the power delivery system
to electrical or electronic devices utilizing the system. However, it has been adopted
worldwide as a standard, and is used primarily due to low cost of manufacture, ease
of quality control during manufacture, and efficient use of space for the power delivery
it is intended to perform.
[0004] The primary limitation of this connection technique is simply the friction fit component.
In some applications where the continuity of power may be critical, such as data or
medical applications, a technique to secure the mated connection may be desirable
to improve the reliability. This may especially be true in mechanically active locations,
such as where vibration is present, or where external activity may cause the cords
attached to the plugs and receptacles to be mechanically deflected or strained in
any manner.
[0006] It is against this background that the secure electrical receptacle of the present
invention has been developed.
SUMMARY
[0007] The present invention, according to claim 1, is directed to securing an electrical
connection. In some cases, mating plug and socket electrical connections may be the
least secure link in the power delivery system. Conventionally, these connections
are secured only by means of a manually inserted friction of electrical contacts fit.
A number of factors may affect the security of this connection. The present invention
provides a variety of secure mechanisms whereby the very forces that would otherwise
tend to pull the connection apart serve to actuate the retention mechanism thereby
securing the mated pair where the frictional engagement of the connection are enhanced,
and/or where the connection is otherwise secured in a manner whereby a deliberate
act is required to release the connection and unintentional disconnections are thus
reduced. The present invention further provides a variety of mechanisms whereby the
user can manually elect to actuate the retention mechanism thereby securing the mated
pair. The invention is of simple construction and highly reliable in operation. Moreover,
the invention can be implemented simply in connection with new or retrofitted receptacle
devices. Thus, the system is compatible with existing plugs and other infrastructure.
[0008] Aspects of the invention are defined in the accompanying claims.
[0009] In accordance with one aspect of the present disclosure, an apparatus is provided
for use in securing an electrical connection. The electrical connection is formed
by a mating structure including prongs of a male assembly and receptacles of a female
assembly (e.g., a cord cap or outlet receptacle) where the connection is broken by
withdrawal of the prongs from the receptacles. It is noted that a wall outlet receptacle
is generally female, while cord caps may be either male or female. The apparatus includes
a clamping element movable between a clamping configuration, where the clamping element
holds the mating structure in a connected state, and a release configuration. An activating
element urges the clamping element into the clamping configuration responsive to a
force tending to withdraw the prongs from the receptacles. In this manner, a force
that would otherwise tend to pull the connection apart will now cause the apparatus
of the present disclosure to clamp the connection in a secure state.
[0010] A variety of structures are possible to implement the noted clamping functionality.
Such structure may be associated with the male assembly and/or the female assembly.
In one implementation, the apparatus is implemented solely in the female assembly.
For example, the clamping element may act on one or more of the prongs of the male
assembly. In a particular implementation the clamping element acts on a ground prong,
maintained at ground potential, such that it is unnecessary to consider potentials
applied to the clamped prong in relation to the design of the clamping element. This
also enables or facilitates compatibility with life safety/ code regulations. However,
it will be appreciated that other prongs may be additionally or alternatively engaged.
[0011] As noted above, the clamping element may include one or more contact surfaces for
contacting one or more of the prongs in the clamping configuration. In this regard,
the activating element may translate movement of the prongs in relation to the receptacle
into movement of the contact surface or surfaces into the clamping configuration.
For example, movement of the prongs may be translated into rotational movement of
the contact surface into an abutting relationship with the clamped prong. Alternatively,
a withdrawal force exerted on the plug/prongs may cause elongate contact surfaces
to engage opposing side of the prong. The apparatus may further include a release
element for moving the clamping element into the release configuration. For example,
the release element may be operated by a user by squeezing, sliding, pulling or pushing
an element of the plug housing. In one implementation, a cord cap housing may be formed
in two sections that are interconnected for sliding relative to each other in telescoping
fashion. The clamping element can then be engaged manually by the user or automatically
in response to a tension on the cord or section of the cord cap hence engaging the
lock, and later released by selecting and sliding the corresponding section of the
sliding housing section to the release position. It will be appreciated that the housing
section can thus be readily accessed to release the clamping element even in crowded
environments (e.g., in a data center rack). Moreover, the housing section to be gripped
for releasing the clamping element may be color coded or otherwise conspicuously identified
to assist users. Also, a variety of methods can be used to indicate if the clamping
mechanism has been released at one time.
[0012] In accordance with another aspect of the present invention a method for manufacturing
the locking electrical receptacle according to claim 1 is disclosed. The user can
activate the securing device by inserting the prongs of the male assembly into the
receptacles of the female assembly or by separately manipulating a locking actuator.
In this mated arrangement, the electrical connection is secured as described above.
The user can further deactivate the securing device by forcing the clamping element
into the release configuration, for example, by squeezing the housing of the male
assembly or sliding the housing section or actuating a tab or button or knob that
is part of the cord cap or other means. In this manner, the electrical connection
can be simply secured and released as desired by the user.
[0013] In accordance with a further aspect of the present disclosure, not forming part of
the invention, the release tension of a locking electrical receptacle can be selected
in relation to a defined standard so as to avoid damage to a cord cap, cordage or
plug or to meet a standard in relation thereto. In this regard, the release tension
of the locking receptacle can be adjusted by varying, among other things, the geometry,
thickness, material qualities and detail shaping of a clamping mechanism. It has been
recognized that setting the release tension too high could result in damage to the
receptacle housing, cordage or a mating plug which could, in turn, result in exposed
wires and a safety hazard. Moreover, standards may be defined for release tension
in relation to such concerns or others. An associated methodology in accordance with
the present disclosure involves providing a locking electrical receptacle with a clamping
element; determining a release tension limit for the receptacle in relation to a standard
for safe operation of the electrical connection; determining a specification or setting
of the clamping element to conform to the release tension limit; and constructing,
or setting an adjustment mechanism of, the locking electrical receptacle in accordance
with the specification or setting. For example, the release tension can be coordinated
with a structural specification of an end cap or plug or cord so as to substantially
ensure that the end cap or plug or cord will not break or fail due to strain associated
with excessive release tension. In this manner, the characteristics of the locking
electrical receptacle can be varied to address safety concerns or related standards
or to match a desired setting of a user (which may change from time-to-time or depending
on the application at issue).
[0014] In accordance with a still further aspect of the present disclosure, not forming
part of the invention, a strain relief mechanism is provided in connection with a
locking mechanism of an electrical connection. As noted above, a potential concern
in relation to a locking electrical connection is damage to an end cap, plug, cord
or other structure, particularly where a high relief tension is desired. To alleviate
such concerns, a strain relief structure is provided for transmitting a strain, associated
with operation of a clamping mechanism for holding mating connection structure in
a connected state, from the clamping mechanism to a power cord or other structure.
For example, a clamping mechanism may be provided in a receptacle end cap for engaging
one or more prongs of a plug. In such a case, strain relief structure may be provided
that extends across the length of the end cap from the clamping mechanism for attachment
to the power cord, e.g., by crimping, welding or otherwise joining. Alternatively,
the strain may be transmitted to other structure separate from a receptacle/plug,
such as a wall receptacle support structure. The strain relief mechanism thereby avoids
hazards associated with undue stress on the end cap or other structure and reduces
or substantially eliminates the need for other structural enhancement of the end cap
or other structure.
[0015] In accordance with another aspect of the present disclosure, an apparatus is provided
for use in securing an electrical connection. The electrical connection is formed
by a mating structure including prongs of a male assembly and receptacles of a female
assembly (e.g., a cord cap or outlet receptacle) where the connection is broken by
withdrawal of the prongs from the receptacles. It is noted that a wall outlet receptacle
is generally female, while cord caps may be either male or female. It also noted that
receptacles used for electronic data processing (EDP) equipment are generally male.
That is, the housing of such receptacles receives a portion of the housing of a plug,
but the connection prongs are in the receptacle, not the plug. The apparatus includes
a retention element movable between a secured configuration, where the retention element
holds the mating structure in a connected state, and a release configuration. An activating
element urges the retention element into the secured configuration. It may be designed
to be responsive to a force tending to withdraw the prongs from the receptacles. In
this manner, a force that would otherwise tend to pull the connection apart will now
cause the apparatus of the present disclosure to retain the connection in a secure
state.
[0016] A variety of structures are possible to implement the noted retention functionality.
Such structure may be associated with the male assembly and/or the female assembly.
In one implementation, the apparatus is implemented solely in the male assembly. For
example, the retention element may act on one or more surfaces of the female assembly.
In a particular implementation the retention element acts on two or more surfaces
of the female receptacle. Upon the application of a force that would tend to pull
the connection apart, a component of the male assembly is moved to press or press
more firmly on the walls of the female assembly via a mechanism activated by such
force. The part of the male assembly that contacts the surfaces of the receptacle
may incorporate a suitable component made of materials (for example high co-efficient
of friction elastomers) which may be specifically chosen and shaped to optimize its
function or be a hybrid design that combines yet other materials such as metal inserts
or pieces to best perform its function. The design may utilize another material component
such as a lever, cam or ramp with suitable mechanical and frictional properties. The
elastomer or other component is forced into high pressure contact with the walls of
the receptacle by the mechanism. The contacting surface may be equipped with a high
friction material to increase the mechanical friction interlock of the male assembly
and the receptacle. The elastomer can be shaped in a variety of shapes. For example,
an elastomeric ring may extend peripherally around the interface between the mail
assembly and the female assembly or receptacle. However, the contact surface need
not extend across the entire interface, but may be present only at one of more sections
of the interface. Generally, it may be useful to provide the contact surface on opposing
surfaces so that they balance and act against one another. The location of these surfaces
may be selected to avoid interfacing structure of the male and/or female assemblies
and/or to exert pressure on structurally stronger or reinforced surfaces. In one embodiment,
contact surfaces or gripping elements provided at the corners of a generally rectangular
interface. In this manner the security of the connection can be greatly increased,
so that the connection will maintain its integrity in a mechanically active environment
and resist inadvertent disconnection up to a desired or preset pull force. This also
enables or facilitates compatibility with life safety/ code regulations.
[0017] As noted above, the retention element may include one or more contact surfaces for
contacting one or more surfaces of the mating receptacle (which can be either male
or female, for example IEC C13 and C14 plugs and receptacles as used in plugstrips
and EDP equipment power inputs) in the retained configuration. In this regard, the
activating element may translate movement of the plug in relation to the receptacle
into movement of the contact surfaces into the retained configuration. For example,
movement of the plug may be translated into movement of the contact surfaces into
an abutting relationship with one or more of the receptacle surfaces. The apparatus
may further include a release element for moving the retention element into the release
configuration. For example, the release element may be operated by a user by squeezing,
sliding, twisting, pulling or pushing an element of the plug housing. In one implementation,
a cord cap housing may be formed in two sections that are interconnected for sliding
relative to each other in telescoping fashion. The outer housing may be moved by the
action of the user pushing, pulling or squeezing directly on the housing or by the
user manually operating a manual actuation element that moves the outer housing between
the secured and released configurations. The retaining element can thus be engaged
manually by the user or automatically in response to a tension on the cord or section
of the cord cap hence engaging the retention function. It can later be released by
selecting and moving the corresponding section of the sliding housing section to the
release position or moving the manual actuation element to the release position. It
will be appreciated that the housing section or manual actuation element can thus
be readily accessed to release the retention element even in crowded environments
(e.g., in a data center rack). Moreover, the housing section or manual actuation element
to be gripped for releasing the retention element may be color coded or otherwise
conspicuously identified to assist users in identifying if the mechanism is currently
secured or unsecured. It can also be textured or shaped to assist the user in gripping
it. Also, a variety of methods can be used to indicate if the retention mechanism
has been released at least one time.
[0018] In accordance with another aspect of the present disclosure, a method for using a
securing device is provided. The securing device includes a retaining element and
an activating mechanism (either automatic or manual) as described above. The user
can activate the retaining element by separately manipulating a locking actuator after
insertion. In this mated arrangement, the electrical connection is secured as described
above. The user can further deactivate the securing device by forcing the activating
element into the release configuration, for example, by squeezing the housing of the
male assembly or sliding the housing section or actuating a tab or button or twisting
a nut or knob that is part of the cord cap or other means. The methods that utilize
a nut (screw) or knob (swash plate or other method) to actuate the retaining element
can incorporate a simple ratchet mechanism (that allows a nut or knob to be turned
in either direction in small indexed increments) to allow the user to select and adjust
the tightness of the nut or the knob and in turn adjust the force required to separate
the secured connection. Also, the size and shape of the nut or the screw and the mechanical
advantage that they deliver can be selected to make it difficult or impossible for
an average user to damage the securing mechanism or the plug or receptacle by excessive
manually applied force. This feature offers a programmable release mechanism, where
the force required to break the connection can be "programmed" into the design and
further made adjustable and selectable by the user within a desired range of connection
retention force values. Also, the characteristics of the mechanism, combined with
the geometry and range of motion offered by the ratcheted nut or knob can be used
to compensate for a wide range of dimensional tolerances as are commonly found in
the production plugs and receptacles. In this manner, the electrical connection can
be simply secured and released as desired by the user while preventing damage to the
components of the connected plug and receptacle.
[0019] In accordance with a further aspect of the present invention, another method for
using a securing mechanism is provided. In another implementation of the retention
mechanism, the apparatus can be implemented in either the female or the male assembly.
One or more retention tabs or hooks that can be appropriately shaped and of variable
width can be provided. They can be made of appropriate materials and geometry. The
retention tabs or hooks will engage in one or more openings, e.g., slots, that are
provided in the matching receptacle at an appropriate location. Most commercially
available receptacles often have such an opening available, it is part of a finger
in the receptacle that allows the receptacle to snap into a panel. These openings
are not always provided, but these receptacles could easily be modified to provide
such openings in every model, both single receptacle and multiple receptacle molded
assemblies. Such modifications would be simple and low cost to make and also would
likely be quickly certified by safety certification organizations such as Underwriters
Laboratories. Therefore this retention mechanism may be easy and quick to bring to
market therefore having significant commercial and economic value. The tab or hook
retention mechanism can be designed to either engage automatically if an opening is
available (e.g., due to a spring loaded configuration) or manually using a user activated
manual mechanism. It can be activated and/or released using a variety of methods that
are described herein, e.g., for mechanically withdrawing the hooks from the openings.
It could also be combined with other retention mechanisms that are described herein.
[0020] In accordance with a further aspect not forming part of the invention invention,
the release tension of a secure retention electrical plug or receptacle can be selected
in relation to a defined standard so as to avoid damage to a cord cap, cordage or
plug or to meet a standard in relation thereto. In this regard, the release tension
of the secure receptacle can be adjusted by varying, among other things, the geometry,
thickness, material qualities and detail shaping of a retention mechanism. Further,
a programmable release tension mechanism can be incorporated as part of the design
of the retention mechanism. It has been recognized that setting the release tension
too high could result in damage to the receptacle housing, cordage or a mating plug
which could, in turn, result in exposed wires and a safety hazard. Moreover, standards
may be defined for release tension in relation to such concerns or others. An associated
methodology in accordance with the present disclosure involves providing a secure
electrical receptacle with a retention element; determining a release tension limit
for the receptacle in relation to a standard for safe operation of the electrical
connection; determining a specification or setting of the retention element to conform
to the release tension limit; and constructing, or setting an adjustment mechanism
of, the secure electrical receptacle in accordance with the specification or setting.
For example, the release tension can be coordinated with a structural specification
of an end cap or plug or cord so as to substantially ensure that the end cap or plug
or cord will not break or fail due to strain associated with excessive release tension.
In this manner, the characteristics of the secure electrical receptacle can be varied
to address safety concerns or related standards or to match a desired setting of a
user (which may change from time-to-time or depending on the application at issue).
[0021] In accordance with a still further aspect of the present disclosure, not forming
part of the invention, a strain relief mechanism is provided in connection with a
retention mechanism of an electrical connection. As noted above, a potential concern
in relation to a secure electrical connection is damage to an end cap, plug, cord
or other structure, particularly where a high relief tension is desired. To alleviate
such concerns, a strain relief structure is provided for transmitting a strain, associated
with operation of a clamping mechanism for holding mating connection structure in
a connected state, from the retention mechanism to a power cord or other structure.
For example, a retention mechanism may be provided in a receptacle end cap. In such
a case, strain relief structure may be provided that extends across the length of
the end cap from the retention mechanism for attachment to the power cord, e.g., by
crimping, welding or otherwise joining. Alternatively, the strain may be transmitted
to other structure separate from a receptacle/plug, such as a wall receptacle support
structure. The strain relief mechanism thereby avoids hazards associated with undue
stress on the end cap or other structure and reduces or substantially eliminates the
need for other structural enhancement of the end cap or other structure.
[0022] In accordance with a further aspect of the present disclosure, not forming part of
the invention, the locking electrical receptacle function can be implemented with
a mechanism that locks or unlocks multiple receptacles, e.g., every receptacle in
a plugstrip at one time. This mechanism has the following benefits.
- 1. The actuation mechanism can be separate and external to the receptacle, which can
incorporate the retention mechanism. This makes the actuation mechanism simpler to
construct, since more space is available to work in.
- 2. The retention mechanism can operate as a security mechanism, preventing the insertion
of plugs into plugstrip receptacles when in the locked state.
- 3. The actuation mechanism can be operated via a number of methods: 1) manually via
a lever on a side of the plugstrip, which can be removable if desired. 2) manually
via a rotary knob, which can be removed if desired 3) a locally or remotely controllable
motor, solenoid or other electronically controllable mechanical means.
- 4. The actuation mechanism can be secured via a turnkey which can act to control either
the local manual or remote operable mechanisms.
- 5. Standard plug types can be locked into the plugstrip without modification. The
shape of the prongs in the plugs does not matter, any shape (flat, round, etc.) can
be accommodated by the mechanism.
- 6. The mechanism can be more robust due to the larger form factor of the plugstrip
vs. the receptacle.
- 7. The mechanism can function as the electrical distribution path to the receptacles
in the plugstrip, eliminating the need for separate wires to the plugstrip.
[0023] An example instantiation of a possible mechanism is now described. The example used
is for single phase receptacles, the most common type, but multi-phase receptacles
can be adapted to the mechanism. Referring to Figs. 26A -26C, a set of nine linear
conductive plates of appropriate material are organized into sets of three assemblies.
Each set of plates has apertures formed into it that are matched to the type of plug
prong the receptacle fits. The apertures are formed so that they have a spring action
relative to the shape of the plug prong that will pass through them. This is necessary
to insure good mechanical and electrical contact for the range of dimensional variance
in production plug prongs, especially when the locking mechanism is unlocked but electrical
conductivity must be maintained to inserted plugs. The spring function also can act
as a programmable release mechanism, to insure that if the plug is pulled out of the
receptacle, it will come out at a given force level. The receptacle has three channels
formed into it, each channel accepts one of the three sets of plates which pass through
the receptacle along the long axis of the plugstrip and at 90 degrees to the direction
the prongs of the plugs will be inserted into the receptacle. Each channel in the
receptacle is sufficiently separated from the other channels to insure that each set
of three plates are electrically isolated from each other. Each set of three plates
are free to move along their long axis (parallel to the long axis of the plugstrip)
relative to each other. At one end of the plugstrip one or more of each set of three
plates is connected to a cam mechanism which moves one or more of said plates relative
to the other plates, creating a frictional mechanical lock on the prong of an inserted
plug or preventing a plug which is not yet fully inserted from being inserted into
the receptacle. The cam mechanism can be operated as described above. The other plates
insure that the plug in the receptacle is not "twisted" when the locking mechanism
is set to the locked position. The plates can be made of conductive material so that
they can be used to distribute electricity to each receptacle, avoiding the need for
distribution wiring to each receptacle. It can be appreciated that by having the ability
to grasp all of the prongs of the plug at once, that if such prongs have a tension
limit set in relation to a defined agency standard (for example Underwriters Laboratory)
so as to avoid damage to a cord cap, cordage or plug, by setting the programmable
release function to an appropriate value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024]
Figures 1A-1C illustrate the operation of an embodiment of a clamping mechanism in
accordance with the present disclosure.
Figures 1D-1F and 1H-1J illustrate the operation of another embodiment of a clamping
mechanism in accordance with the present disclosure.
Figure 1G illustrate the operation of another embodiment of a clamping mechanism in
accordance with the present disclosure.
Figures 2A-2B illustrate an embodiment of a locking electrical receptacle in accordance
with the present disclosure, using the clamping mechanism described in Figures 1A-1C.
Figure 2C illustrates an embodiment of a locking electrical receptacle in accordance
with the present disclosure, using the clamping mechanism described in Figures 1D-1F,
1H-1J or 1G.
Figures 3A-3B illustrate an application for the locking electrical receptacle shown
in Figures 2A-2B.
Figures 4A-4C illustrate an apparatus for providing a locking feature for a standard
receptacle in accordance with the present disclosure.
Figure 5 illustrates an embodiment of a standard duplex locking receptacle in accordance
with the present disclosure.
Figures 6A-6B illustrate an embodiment of a locking receptacle that includes a cam
lock in accordance with the present disclosure.
Figures 7A-7D illustrate an embodiment of a device for locking a mating assembly of
a plug and receptacle in accordance with the present disclosure.
Figures 8A-8C illustrate an embodiment of plug that includes a toggle locking mechanism
in accordance with the present disclosure.
Figures 9A-9B illustrate another embodiment of a plug that includes a divergent spring
tip locking mechanism in accordance with the present disclosure.
Figures 10A-10B illustrate a further embodiment of an end cap incorporating a locking
mechanism in accordance with the present disclosure.
Figures 11A-11B illustrates an alternative shaping of a spring prong retainer in accordance
with the present disclosure that enables improved cord retention and increased overall
strength.
Figure 12 is a perspective view of an alternative embodiment of a spring prong retainer
in accordance with the present disclosure.
Figures 13A-15B show an alternative embodiment of a locking spring prong retainer
electrical receptacles and spring prong retainers in accordance with the present disclosure.
Figures 16A-18K illustrate the operation of several embodiments of retention mechanisms
in accordance with the present invention.
Figures 19-22 illustrate the operation of another embodiment of a retention mechanism
in accordance with the present disclosure.
Figures 23-24 illustrate an embodiment of plug that includes a tab or hook retention
mechanism in accordance with the present disclosure.
Figure 25 illustrates an embodiment of a mechanism that insures positive retraction
of the outer shell when the locking nut is turned to the release position in accordance
with the present disclosure.
Figures 26A-26J show a locking plugstrip in accordance with the present disclosure.
DETAILED DESCRIPTION
[0025] While the disclosure is susceptible to various modifications and alternative forms,
specific embodiments thereof have been shown by way of example in the drawings and
are herein described in detail. It should be understood, however, that it is not intended
to limit the invention to the particular form disclosed, but rather, the invention
is to cover all modifications, equivalents, and alternatives falling within the scope
and spirit of the invention as defined by the claims.
[0026] Figures 1A-1C illustrate the operation of an embodiment of a clamping mechanism for
securing a mated electrical connection that may be included in a locking receptacle
of the present disclosure. In each of the Figures 1A-1C, the bottom portion represents
a side view of a prong 16 and a clamping mechanism 12, while the top portion represents
a perspective view. Referring first to Figure 1A, the prong 16 of a plug is shown
prior to insertion into a receptacle 10. The prong 16 may be a ground prong of a standard
plug (e.g., an IEC 320 plug, a NEMA 5-15, or the like) and may be various sizes and
shapes. Further, the receptacle 10 may be the ground receptacle or other receptacle(s),
of a standard outlet (e.g., a NEMA standard cord cap, an IEC 320 cord cap, or the
like) that is operative to receive a standard plug. The receptacle 10 also includes
the clamping mechanism 12 that is coupled to a pivot 14. The clamping mechanism 12
includes an aperture that is sized to be slightly larger than the prong 16, such that
the prong 16 may only pass through the aperture when the length of the clamping mechanism
is substantially perpendicular to the length of the prong 16. That is, the design
of the clamping mechanism 12 is such that a simple slide on and capture technique
is utilized.
[0027] Figure 1B illustrates the prong 16 when inserted into the receptacle 10. As shown,
the prong 16 passes through the aperture in the clamping mechanism 12 and into the
receptacle 10, such that the corresponding plug and outlet are in a mated position.
The clamping mechanism 12 further may include a stop (not shown) to prevent the clamping
mechanism 12 from pivoting during the insertion of the prong 16. In this regard, during
insertion of the prong 16, the length of the clamping mechanism 12 will remain substantially
perpendicular to the length of the prong 16, which permits the passage of the prong
through the aperture of the clamping mechanism 12.
[0028] Figure 1C illustrates the gripping function of the clamping mechanism 12 in reaction
to a force on the prong 16 that tends to withdrawal the prong 16 from the receptacle
10. In reaction to a withdrawal of the prong 16, the clamping mechanism 12 angularly
deflects (i.e., rotates) about the spring pivot 14, causing the aperture in the clamping
mechanism 12 to grip the prongs 16. Thus, the very force that tends to withdraw the
prong 16 from the receptacle acts to actuate the clamping mechanism 12 to engage the
prong 16, thereby preventing the withdrawal of the prong 16, and maintaining the electrical
connection of the mated assembly. The clamping mechanism 12 may be constructed of
any suitable material, including a high strength dielectric with an imbedded metallic
gripping tooth. An all-metallic clamping mechanism may also be used if the prong 16
is a ground prong. In this regard, an all-metallic clamping mechanism may be used,
e.g., for other prongs, though modifications may be required to obtain approval by
underwriting bodies.
[0029] Figures 1D-1F & 1H-1J illustrate the operation of another embodiment of a clamping
mechanism for securing a mated electrical connection that may be included in a locking
receptacle of the present disclosure. In each of the illustrations 500-505 of Figure
1D, the top row of figures represents the end-on views of the clamping mechanism and
the bottom row represents side views of the clamping mechanism with an electrical
contact prong in the states of: 1) disengagement 500 , 2) being inserted 501, 3) fully
inserted 502, 4) fully inserted under tension 503, 5) being released 504 and 6) during
contact removal 505. The example clamping mechanism as shown in Figure 1E has two
channels 606 that grip the sides of the contact and cross-link springs 603 connecting
the channels. It should be noted that the clamping mechanism can act as both the electrical
contact and clamping mechanism together or can be only a clamping mechanism that is
integrated with a separate electrical contact. Figures 1H-1J shows the clamping mechanism
acting as both the electrical contact and clamping mechanism and Figure 1F shows a
clamping mechanism that is suitable for use with a separate electrical contact. Details
of Figure 1H include the gripping channels 902, the cross-link springs 901, the integrated
electrical conductor crimp 903, the release shaft 904 and the release shaft contact
nub 905. Possible instantiations can be made of one suitable material or several materials
(for example steel and copper) to optimize the functionality of the clamping mechanism,
electrical and mechanical properties, ease of manufacture and cost. The materials
can joined together or secured to function together by any suitable means such as
mechanical interlock, fasteners, gluing, etc. as is needed to optimize their function
and minimize their cost.
[0030] A possible example of this would be a clamping mechanism that is also an electrical
contact made of annealed brass or phosphor bronze or other suitable material. Due
to the expansion characteristics of the chosen materials, the expansion associated
with heating of the retainer contact (receptacle) and more specifically the expansion
of the cross-link springs, from any resistance in the connection of it to the inserted
electrical prong (Note that the prong could be different shapes, it could be a pin
for example), will result in progressive tightening of the grip function. Even if
the receptacle is not "locked" to the prong upon initial insertion, e.g. no extraction
force is applied to tighten the gripping mechanism, and the only bearing force applied
to the contact surfaces is the force of the cross-link spring action, when current
is applied, the resistance at the junction of the socket and prong will result in
some degree of heating. If the resistance is high enough, say the prong is under-sized,
or damaged and not uniformly in contact with the channels, the temperature of the
assembly will start to rise. In addition, the electrical connection between the channels,
that is the channel that is connected directly to the incoming wire and the opposing
channel connected via the cross-link springs, can be manipulated in cross section
to have additional heating at higher current levels such that more heating is occurring
in the cross-link springs than elsewhere. In any case, heating of the cross-link springs
will result in expansion. Since the heat sinking is largely via the inserted prong,
and subsequently the wire of the associated connection, the temperature of the cross-link
spring will be higher than the prong temperature average. Hence slightly less expansion
of the prong will be present. At some point the differential will allow the natural
tendency of the spring loaded and racked socket receptacle to overcome the molecular
lock (static friction) between the channels and the edges of the prong. The channels
will move slightly with regards to the prong and a new engagement will be established.
At this point, the electrical resistance will drop due to the newly established, and
slightly tighter connection between the channels and the prong, and the whole thing
will start cooling. Now, the cross-link springs will shorten, and the force exerted
on the bearing points between the channels and the prong will increase dramatically
because the tangential force, similar to the force applied when pull-out force is
applied, and the electrical connection will be re-established much more effectively.
This in turn will reduce the resistance further and effectively "lock" the receptacle
to the prong, and guarantee superior electrical connection, even with imperfect mating
surfaces. It is a re-generative condition that is responsive to poor connections,
and tends to self-heal a poor electrical connection.
[0031] Figure 1E shows the mechanical properties of the clamping mechanism. An electrical
contact 600 (or other plug structure) is inserted into the clamping mechanism 601.
The dimensions of the clamping mechanism are set so that the contact will spread the
clamping mechanism open. In this regard, the forward end of the clamping mechanism
(the end that is first contacted by the electrical contact) may be flanged outwardly
to capture the contact and facilitate spreading of the clamping mechanism. This spreading
action is shown in Figure 1D 511. The transverse cross-link springs 603 act to resist
the spreading open of the clamping mechanism. This insures that the edges of the electrical
contact 600 are biased to touch the channels at defined contact points 609. Differently
shaped electrical contacts and/or clamping mechanisms would have different contact
points and/or surfaces. In the illustrated embodiment, the contact points/surfaces
where clamping occurs are primarily or exclusively on the top and bottom surfaces
of the prong, rather than on the side surfaces where electrical connections are typically
made. This may be desirable to avoid concerns about any potential degradation of the
electrical contact surfaces thought it is noted that such degradation is unlikely
given that the clamping forces are spread over a substantial length (and potentially
width of the contact. Once the electrical contact prong 600 has been inserted into
the clamping mechanism 601, any pulling force F(pull) 604 that acts to remove the
prong 600 from the clamping mechanism 601 will result in a clamping force F (grip)
605 being exerted on the sides of the prong 600. The clamping force is generated by
the action of the transverse cross-link link springs pulling on the channels 606 on
each side of the clamping mechanism such that the channels are urged towards one another.
The relationship of the forces will be generally F(grip)= F(pull)/tangent (angle theta).
Thus, the clamping force F(grip) will increase faster than the force F(pull) that
is acting to remove the prong 600 from the clamping mechanism 601. Therefore the grip
of the clamping mechanism 601 on the prong 600 will become more secure as the force
trying to extract the prong 600 increases. Once the gripping mechanism has been actuated
by a pull force 604, friction will tend to keep the gripping mechanism tightly engaged.
To release the gripping mechanism, the release rod 607 is pushed, generating a force
F(release) 608. This force will decrease the angle theta and urge the channels away
from one another, rapidly decreasing the gripping force F(grip) 605 and allowing the
prong 600 to be easily removed from the gripping mechanism 601. The release force
608 needed to effect release can be very small.
[0032] In one possible embodiment, associated with a standard NEMA C-13 outlet, the transverse
cross-link spring may be formed from copper or a copper alloy and have a thickness
of about 50/1000 - 75/1000 of an inch. In such a case, the curve 602 may be generally
circular in shape with a radius of curvature of about 75/1000 of an inch. The curve
602 may extend into the cross-link spring 603 so that a narrowed neck, from radius-to-radius,
is formed in the cross-link spring 603. Such a curve 602, in addition to affecting
the operational properties of the gripping mechanism as may be desired, avoids sharp
corners that could become starting points for cracks or accelerate metal fatigue.
The neck also helps to better define the pivot point of the cross-link spring 603
in relation to the channels as may be desired. It will be appreciated that specific
operational characteristics, such as (without limitation) the amount of any slight
movement allowed before locking, the total amount and location of clamping forces
exerted on the prong, the force level (if any) where the clamping mechanism will release,
and the durability of the clamping mechanism for frequent cycling, may be application
specific and can be varied as desired. Many other configuration changes and construction
techniques are possible to change these operational characteristics. For example,
the cross-link spring (or a portion thereof) may be twisted (e.g., at a 90° angle
to the plane of stamping of the material) to affect the pivot point and flexing properties
of the spring as may be desired.
[0033] The choice of material, thickness and geometry and shaping of the apparatus affect
the operational properties of the gripping mechanism 601. The transverse cross-link
springs can have their spring constant affected by all of these variables. For example
the radius, location and shape of the curve 602 and the thickness of the neck of the
transverse cross-link spring 603 can be varied to achieve differing values of spring
constants. This can be desirable to optimize the pre-tension gripping force exerted
by the spring on a contact inserted into the retention mechanism or the range of contact
sizes the gripping mechanism will function with. Note: The pre-tension gripping force
is defined as the gripping force exerted on the contact 600 by the action of the transverse
cross-link springs 603 before any pull force 604 is placed on the contact.
[0034] Referring to Figure 1G another possible instantiation is shown. In this instantiation,
the operation of the mechanism is similar to the_operation described in (1-D through
1F). As tension is applied to the assembly between Force Pull 710 on the prong 706
and the Counter-Force Pull 711, bearing forces at the contact points (703,707) of
the channels (704, 705) and the inserted contact prong 706 (note that the prong could
have different shapes, it might be a pin for example) increase exponentially, resulting
in immediate capture of the prong by the channels. As F Pull 710 increases, the tension
in the cross-link springs 701 continue to increase as well. The cross-link springs
are crescent shaped in this instantiation as opposed to the straight springs described
in Figures 1D-1F & 1H-1J. The crescent shape allows the cross-link springs to now
have two actions. First, they have a spring action at the connection point to the
channels (704, 705) and secondly they have a spring action along the long axis of
the cross-link spring (701). The addition of the spring action along the long axis
allows the cross-link spring to have a predictable ability to lengthen, or stretch.
As F Pull 710 continues to increase, the tension in the cross-link springs 701 continue
to increase to a point where the cross-link spring begins to stretch along its long
axis. At this point, the relationship between the F Pull 710 applied and the resulting
grip forces at the contact points (703,707) of the channels (704, 705) and the inserted
contact prong 706 ceases to increase. Now, increasing Force Pull 710 results in overcoming
the friction at the contact points 703,704, and the contact pin 706 will move in relationship
to the channels (704, 705) and hence the gripping mechanism 700. If Force Pull 710
is maintained, the contact prong 706 will become extracted from the channels (704,
705) completely. This condition allows the assembly 700 to have a predictable point
in tensile relationships where a plug and receptacle can be separated without damage
to either principal component, the prong or the gripping mechanism (which can be a
gripping mechanism that is also an electrical contact or a separate gripping mechanism
with integrated electrical contact as noted earlier).
[0035] Referring again to Figure 1D, the prong 530 of a plug is shown prior to insertion
into a receptacle with an electrical contact represented by 510.. The prong 530 may
be a ground prong or other prong of a standard plug (e.g., an IEC 320 plug, a NEMA
5-15, or the like) and may be various sizes and shapes. Further, the receptacle containing
the electrical contact 510 may be the ground receptacle or other receptacle(s), of
a standard outlet (e.g., a NEMA standard cord cap, an IEC 320 cord cap, or the like)
that is operative to receive a standard plug. The receptacle includes the clamping
mechanism 520 and may utilize more than one clamping mechanisms in one receptacle.
The design of the clamping mechanism 520 is such that a simple slide on and capture
technique is utilized.
[0036] Other clamping mechanisms are possible in accordance with the present disclosure.
For example, a wire mesh, formed and dimensioned so as to receive a contact, prong
or other plug structure (collectively, "contact") therein, may be utilized to provide
the clamping mechanism. The wire mesh is dimensioned to frictionally engage at least
one surface of the contact when plugged in. When a force is subsequently exerted tending
to withdraw the contact from the receptacle, the wire mesh is stretched and concomitantly
contracted in cross-section so as to clamp on the contact. A Kellem-style release
mechanism may be employed to relax the weave of the mesh so that the contact is released.
Such a gripping mechanism may be useful, for example, in gripping a cylindrical contact.
[0037] Figures 2C illustrate a cross section of one possible embodiment of a locking electrical
receptacle 820. The receptacle 820 is an IEC type 320 cord cap receptacle that includes
one or more gripping mechanisms 828. The receptacle 820 includes an inner contact
carrier module 824 that contains a gripping mechanism and electrical contacts 826
and 828. Attached to the gripping mechanism and electrical contact sockets are wires
836 and 838 that extend out of the receptacle 820 though a cord 834. The carrier module
824 may be attached to a cord strain relief 832 that functions to prevent the cord
from separating from the cord cap or otherwise resulting in damage to the assembly
when a force is applied to the cord 834. Figure 2C demonstrates one possible release
mechanism actuation method. Specifically, the receptacle 820 is formed in telescoping
fashion with a shell 822 that slides on the carrier module 824 and strain relief 832.
A protrusion 850 on shell 822 engages a release 851 of mechanism 828 such that sliding
the shell 822 engages the mechanism 828 to its release configuration. The clamping
mechanisms described in Figures 1D-1J can be combined many of the other release mechanisms
described in the incorporated filings.
[0038] Figures 2A-2B illustrate a cross section of one embodiment of a locking electrical
receptacle 20. The receptacle 20 is an IEC type 320 cord cap receptacle that includes
a locking mechanism. The receptacle 20 includes an inner contact carrier module 24
that houses contact sockets 26 and 28. Attached to the contact sockets are wires 36
and 38 that extend out of the receptacle 20 though a cord 34. The carrier module 24
may be attached to a cord strain relief 32 that functions to prevent the cord from
separating from the cord cap or otherwise resulting in damage to the assembly when
a force is applied to the cord 34. A spring prong retainer 40 is disposed adjacent
to a surface of the carrier module 24, and extends across a prong-receiving portion
44 of the receptacle 20. One end of the spring prong retainer 40 is bent around the
end of the inner contact carrier module 24, which secures it in the assembly (underneath
the over-molded material 32).
[0039] Alternatively, the spring prong retainer 40 may be secured to the inner contact carrier
module 24 by a screw or other fastener, and/or embedded in the module 24. A section
of the spring prong retainer 40 that is embedded in the module 24 or alternatively
secured in the cord cap via over molded material may be configured (e.g., by punching
a hole in the embedded section and/ or serrating the edges or otherwise shaping it)
to enhance the anchoring strength in the embedded section. The other end of the spring
prong retainer 40 is in contact with a telescopic lock release grip 22. Similar to
the clamping mechanism 12 shown in Figures 1A-1C, the spring prong retainer 40 includes
an aperture sized to permit the passage of the ground prong of a plug into the socket
26. The aperture in the spring prong retainer 40 may be sized to be slightly larger
than one prong (e.g., the ground prong) in a standard plug such that the aperture
may function as the clamping mechanism for the locking receptacle 20. It can be appreciated
that prongs with different cross-section shapes, for example round prongs, can use
the retention mechanism described herein, with a suitable modification of the aperture
shape and geometry of the spring prong retainer. Such modifications may be specific
to the various shapes of the cross section of various prong types. Such variations
will function in substantially the same manner as the retention mechanism described
herein. The spring prong retainer 40 may further be shaped and constructed, as will
be discussed in more detail below, to inhibit contact with other prongs and provide
a desired release tension. Moreover, the retainer 40 may be retained within a recessed
channel formed in the module 24 to further inhibit transiting or side-to-side displacement
of the retainer 40. The operation of the clamping feature of the spring prong retainer
40 is discussed in detail below.
[0040] Figure 2A illustrates the locking receptacle 20 when there is little or no strain
on the cord 34. As shown, the portion of the spring prong retainer 40 disposed in
the prong-receiving portion 44 of the receptacle 20 is not in a substantially vertical
position. Similar to the operation of the clamping mechanism 12 shown in Figures 1A-1C,
the apertures of the spring prong retainer 40 in this configuration will allow the
prongs of a plug to pass freely into the socket 26 when the prong is inserted. This
is due to the unrestricted change of position of the spring prong retainer 40 to the
substantially vertical position as the prongs of a plug acts upon it.
[0041] Figure 2B illustrates the locking receptacle 20 when a force is applied to the cord
34 of the receptacle 20 in the opposite direction of the grip release handle 30. This
is the "release position" of the receptacle 20 and is shown without the mating prongs
for clarity of operation. Actions that initiate this position are illustrated in Figures
3A and 3B.
[0042] Figure 3A illustrates the operation of the locking electrical receptacle 20 shown
in Figures 2A-2B. When a prong 54 of a plug 50 first enters the receptacle 20 via
an aperture in the lock release grip 22, it encounters the spring prong retainer 40,
which is not in the perpendicular orientation at that time. Upon additional insertion,
the spring prong retainer 40 is deflected into the perpendicular position by the force
applied to it by the prong 54. The prong 54 then passes through the aperture in the
spring prong retainer 40 and into the contact socket 26, making the electrical connection
as required. Upon release of the insertion force, and when no axial strain is applied
to the mated plug 50 and receptacle 20, the spring prong retainer 40 is only partially
displaced from the perpendicular axis. It is noted that there is little separation
between the forward-most surface of the plug 50 and the end of the receptacle of carrier
module 24 adjacent the plug 50 in this connected configuration, i.e., the prong extends
to substantially the conventional extent into the receptacle.
[0043] Figure 3B illustrates in an exaggerated manner the condition of applying axial tension
to the cord 34 of the receptacle 20. A slight retraction motion pulls on the spring
prong retainer 40, thereby increasing the angle of grip and subsequent tightening
of the offset angle of the spring prong retainer 40 and prong 54. The receptacle 20
and the plug 50 are then fully locked in this condition. Upon application of axial
tension between the release grip handle 30 and the plug 50, the position of the spring
prong retainer 40 is returned to the near-perpendicular position as illustrated in
Figure 3A, thereby releasing the spring prong retainer 40 from the prong 54. Upon
release, the receptacle 20 is easily separated from the plug 50. Because the release
grip handle 30 is mounted to slide in telescoping fashion with respect to the carrier
module 24 and can be gripped for prong release from the top or sides, the locking
mechanism can be easily released even in crowded or space limited environments such
as in data centers.
[0044] Figures 13A-13C illustrate an alternative spring prong retainer. In the embodiment
described above and illustrated by Figs. 1A through 3B, the retention gripping points
are along the flat, or semi-flat surfaces of the narrow axis of the prong. The apertures
are rectangular in shape and the top and bottom of the rectangle comprise the contact
locations on the prong. Forces applied to those contact points are limited to the
relationship of the precision of the prong dimensions to the hole dimensions. In the
embodiment of Figure 13A, the aperture has a rectangular top and a bottom half that
narrows down or tapers. This design of aperture contacts the prong at three locations
1100, 1101, 1104 (see Figure 13A - Exaggerated View), on the top of the prong and
on each of the sides at the bottom.
[0045] A significant increase in the gripping force is possible due to the amplification
of the pull torque via not only the angular displacement of the spring prong, but
also the wedging effect at the two adjacent contact points 1100, 1101 at each corner
of the narrow axis of the mating prong 1103. As pull force is exerted on the hook
tab 1106 of the spring retainer 1110, an initial action occurs as described for the
spring prong retainer in Figures 1A thru 1C. After the initial contact is made at
points 1100, 1101, 1104 during the attempt to withdraw the mating prong 1103, the
forces applied to the mating prong 1103 are amplified by the inclined planes of the
bottom of the slot 1100 1001. The tension force formed in the early stage of gripping
by the axial displacement of the spring prong retainer 1110 about the fulcrum point
1105 is amplified greatly to apply a compressive force at the contact points of the
mating prong 1103 and the spring prong retainer bottom contact points 1100 and 1101.
This force is multiplied by about 10 to 1 due to the tension amplification of the
spring prong retainer 1110 about the fulcrum 1105. A total force amplification of
about 80 times can be achieved by this method. It should be appreciated that by adjusting
the angles of the inclined planes 1100 and 1101, and the geometry of metal 1104 forming
the fulcrum 1105, that various amplifications of force can be achieved. It should
also be appreciated that by varying the amplification force, the spring prong retainer
can be tuned to optimally engage with a variety of mating prong materials and finishes.
[0046] Due to this amplification, and the relatively small contact area between the spring
prong retainer, inclined planes 1112 (Figure 13C) 1110, 1101 and the mating prong
1103, forces at least as high as 30,000 pounds psi (30Kpsi) are possible, thus ensuring
positive gripping of the mating prong 1103. It should be appreciated that use of this
alternate method of mating prong capture is also more tolerant of manufacturing variances
in the prongs.
[0047] Figure 13B illustrates the release methodology for this alternate spring prong retainer.
It is similar to that of the spring prong retainer previously described. As release
force is applied to the end of the spring prong retainer 1111 by the face of the outer
shell 1116, the surface of the spring prong retainer 1110 becomes more perpendicular
to the mating prong 1103. In turn, the point of contact at the fulcrum 1105 is disengaged
and the mating prong would normally be free to be extracted, as described for spring
prong retainer 40 of previous embodiments. However, at this point the lower contact
points (illustrated in Figure 13A) 1100, 1101 have the mating prong 1103 captured
between them, and likely a small deflection of the metal of the mating prong 1103
has occurred at those points. The mating prong 1103 is therefore probably not yet
released. As the outer shell 1116 compresses the face of the spring prong retainer
1110, the molded-in ramp in the outer shell 115 begins to push the spring prong retainer
down and in turn pushes the lower contact points 1100 and 1101 (illustrated in Figure
13A) down off of the mating prong 1103. Eventually the entire assembly is disengaged
from the mating prong 1103.
[0048] It should be appreciated that the shape of the spring prong retainer (illustrated
in Figure 13A) contributes to the disengagement characteristics as well. The shoulders
of the spring prong retainer 1107 are placed such that, upon force being applied to
the spring prong retainer to release, the shoulders contact the interior surface of
the outer shell 1116. Continued rotation of the face of the spring prong retainer
closer to perpendicular to the mating prong 1103 results in the entire face of the
spring prong retainer 1111 to be forced down. This action, in conjunction with the
action of the ramp cast into the outer shell 1115 results in positive down force on
the spring prong retainer disengaging the lower contact points 1100 and 1101 (illustrated
in Figure 13 A) from the mating prong 1103.
[0049] Figures 14A-15B illustrate an alternate capture mechanism. Figure 14C illustrates
the principal mechanical components of the capture mechanism. A saddle and strain
relief component 1401 is placed into the plastic connector carrier of the injection
molded receptacle. A capture toggle 1402 is inserted into the two holes at the end
of the saddle 1401. The opposite end of the saddle and strain relief component 1401
is the crimp ring that clamps around the cord end just beyond the start of the outer
jacket or other suitable location depending on the design of the cord. It will be
appreciated that if, e.g., for ease of manufacturing, it is designed to make the strain
relief and clamping mechanism from different materials, such as metals of different
properties, than the carrier or other cord attachment mechanism, this can easily be
done, by separating the attachment method to the cord, such as a crimp ring from the
strain relief piece and then connecting them mechanically. It should be appreciated
that the strain relief mechanism described herein can be used with the two additional
retention mechanisms described earlier.
[0050] Figure 14A illustrates the assembly of the saddle 1401 and the cord assembly 1400,
1407. The cord assembly includes the main cord 1400, an electrical interface terminal
1406, and the interior conductor 1407 of the aforementioned cord that connects to
the terminal 1406. The terminal 1406 rests in the closed end of the saddle and the
strain relief component 1401 and the two components are aligned along the long axis
by relief ways in the outer contact carrier (not shown). If desired or needed, the
terminal 1406 can be mechanically attached or bonded to the saddle and strain relief
component 1401 for ease of assembly, greater strength, or other purposes. The capture
toggle 1402 is placed during manufacture in the saddle between the two holes in the
saddle 1401. The pre-load spring 1403 will press upon the capture toggle 1402 while
the release actuation rod 1404 rests against the opposite side of the toggle.
[0051] Figure 14B shows a side view of this assembly. The outer contact component carrier
1409 houses and contains each of the components and prevents injection molding plastic
from entering the interior of the carrier during the final outer over-mold injection
process. Figure 14B also helps understand the basic operation of the capture assembly.
When the prong of the inserted plug 1405 is inserted into the receptacle, it enters
into the plastic carrier 1409, then into the terminal 1406, and eventually passes
under the toggle 1402 until it is fully inserted and is in the position shown. If
tension is applied to the power cord in attempt to extract it from the mated plug,
the force is transmitted from the cord to the prong 1405 and hence to the toggle 1402
(via the strain relief component and saddle 1401) which is pressed against the top
of the prong 1405 by the pressure of the saddle 1401 on the bottom of the prong 1405,
transmitted through the electrical terminal 1406. The toggle is pre-loaded against
the top of the inserted prong of the plug connector 1405 by the spring 1403. As can
be appreciated the shape of the toggle where it presses down on the prong can be shaped
to control the application of the clamping force to the prong, for example, the toggle
can have a groove to control the force on the prong so as not to twist it. This can
also be done for the base of the saddle and mating terminal if desired or necessary.
A suitably shaped insert between the saddle/ strain relief 1401 and a terminal shaped
to match the insert could accomplish this function. As the force applied to the cord
1407 causes minute movement along the major axis of the assembly, the mating prong
also begins to attempt to retract and the toggle begins to rotate in such a manner
as to force down the top of the inserted mating prong of the plug connector 1405,
squeezing it tighter into the terminal 1406, and hence the terminal is squeezed into
the saddle 1401. The friction between the terminal 1406, the mating prong of the plug
connector 1405 and the saddle 1401 increases rapidly to a point where the movement
is ceased. The pressing down of the mating prong 1405 onto the electrical terminal
1406 also improves the quality of the electrical connection. The prong of the plug
connector 1405 is now functionally locked to the saddle and strain relief component
1401, and hence the cord 1407. Figure 15A illustrates from an end-on view the relationship
of all of the components involved in the locking of the components together. The prong
of the inserted plug 1405 is located in the terminal 1406, which is sandwiched between
the prong 1405 and the saddle 1401.
[0052] Figure 14B illustrates the mechanism to release the connection of the toggle 1402
and the prong of the plug connector 1405. The opposite end of the release rod 1404
can extend through the entirety of the receptacle and protrude out the back of the
connector or assembly where it is user accessible. The release rod 1404 can also be
actuated by other means such as is shown in Fig. 14D. A telescopic section of the
cord cap 1412 which includes a mechanical linkage 1408 can push the release rod 1404
against the toggle 1402 when the telescoping section 1412 is pulled back by the user
to separate the plug assembly from the receptacle assembly (line 1413 indicates the
fully inserted depth of the front face of the plug). In this regard, the range of
motion of the telescoping section 1412 is controlled by elements 1410 and 1411. Pressure
on the opposite end of the rod 1404 transmits to the back of the toggle 1402 and compresses
the spring 1403 slightly. This action rotates the bottom of the toggle 1402 up and
away from the prong of the inserted plug connector 1405 and reduces or eliminates
the contacting force between the toggle 1402 and the mating prong 1405 allowing the
mating prong to move in the retraction direction. The receptacle can then be separated
from the plug. The system can be designed so that the spring 1403 functions to return
the telescopic section 1412 to the locked configuration when the user releases the
section 1412.
[0053] Figure 15A illustrates the end-on view of the principal components of the inserted
prong of the plug connector 1405 and the locking components of the receptacle in cross
section. As mentioned previously, the toggle 1402 has been rotated into a position
such that it is pressing on the prong of the inserted plug connector 1405. The prong
1405 is in turn pressing on the terminal 1406 and in turn the terminal 1406 is pressing
on the bottom of the saddle 1401. It should be appreciated that as axial tension on
the cord is increased the downward force exerted by the toggle 1402 will also increase.
With suitable angles selected, and suitable dimensions of the components, the force
amplification can be about 10 to 1. In other words, 10 pounds of strain force on the
cord will result in about 100 lbs of force exerted on the prong.
[0054] It also should be appreciated that the bottom of the saddle and strain relief component
1401 can be manufactured with a crown shape as shown. This crown shape allows the
bottom of the saddle and strain relief component 1401 to act like a leaf spring when
pressed down by the prong. The spring in the bottom of the saddle allows a very controllable
and predictable force to be applied to the prong 1405 by the combination of the toggle
pressing down on the prong and the spring resisting that force as transmitted by the
prong and terminal. The maximum clamping force of the toggle on the prong is controlled
by the resistance and travel of the spring. This feature can be used as follows. When
strain is put on the cord to pull apart the connection, the toggle increases its force
on the prong and eventually a point will be reached where the spring in (or under
as described in alternative embodiments discussed below) the bottom of the saddle
and strain relief component 1401 starts to flatten out. This action allows the distance
from the base of the saddle and strain relief component 1401 and the tip of the toggle
1402 to increase, allowing the toggle 1402 to rotate. As the tension on the cord continues
to increase, a point will be reached where the distance between saddle and strain
relief component 1401 and the toggle 1402 is great enough that the toggle 1402 will
rotate and be perpendicular to the prong. At this point the tab on the toggle 1402
can no longer add any additional pressure to the prong 1405, and the prong 1405 will
move under the tension applied to the cord 1407 which separates the plug and receptacle.
It should also be appreciated that the tension at which the release occurs can be
reliably predicted to occur and can be varied by the strength and travel of the spring.
The design is somewhat tolerant of manufacturing variances of both the inserted connector
prong and the mechanical components of the locking mechanism. It should also be appreciated
that the tension at which the mated connection releases under strain can be reliably
pre-set.
[0055] In this design, Figure 15A illustrates the end-on view of the saddle and strain relief
component 1401 with the cord crimp end away from the viewer. The crown spring depicted
in the front 1521 view has the function of controlling the release point of the connected
assembly under strain conditions. In Fig. 15B the crown spring is shown with a hole
1541 that is used to modify the strength and travel of the crown spring. However,
other means such as the thickness or type or temper, etc., of the material used can
be selected to control the spring function. Observing that the location of the hole
1541 is located directly under the saddle section of the saddle and strain relief
component 1401, it should be appreciated that the strength of the crown spring action
is modified. The absence of a hole will allow maximum resistance to compression of
the spring crown, and a large hole will introduce significant reduction in spring
strength. By reducing the spring strength, the release point of the mated connector
components is subsequently reduced. Hence, the retention capacity of the locking receptacle
can reliably set to specific release tensions. It will be appreciated that this design
further promotes ease and lower cost of manufacture. The die that stamps the strain
relief can have an insert that can be changed to vary the size of the hole 1541 in
the leaf spring for various values of release tension. Other means of setting the
strength and travel of the spring can be used, for example the thickness and shape
of the material or other means. Also, other means that use a uniform or variable strength
spring of a suitable type (hairpin, leaf, elastomer, etc) to press on the bottom of
the saddle 1401 directly below the toggle 1402 can be used. The saddle in this case
would not need to incorporate a spring, the spring would be separate from the saddle.
This would permit the addition of a factory and/ or end user spring force adjustment
mechanism, such as a screw. This mechanism would control the strength and travel of
the spring pressing on the saddle and hence the release tension of the gripping mechanism
as was described earlier. The range of adjustment could be controlled to meet any
needed requirement. It can be appreciated that being able to reliably set the release
tension is extremely useful - it allows a locking cord to be made that does not require
a separate release mechanism. The release is done by the locking mechanism at the
desired tension level.
[0056] Figure 14C depicts an orthogonal view of the saddle and strain relief component 1401.
The grip ring 1408 at the end of the saddle and strain relief component 1401 is shown
as an integral part of the saddle and strain relief component 1401. This ring can
also be a separate compression ring that is inserted over the end of the saddle and
strain relief component 1401, where the end of the saddle and strain relief component
1402 can be shaped appropriately to be sandwiched between said compression ring and
the end of the attached cord. The alternate method of attaching the saddle and strain
relief component 1401 to the cord is mentioned due to the potential difficulties in
compound heat treatment along the length of the saddle and strain relief component
1401. The saddle end of the saddle and strain relief component 1401 will generally
be heat treated, while the crimp ring end must remain malleable. Although it is possible
to manufacture the saddle and strain relief component 1401 with these characteristics,
it may be more economical to manufacture an alternately shaped saddle and strain relief
component 1401 and assemble it to the cord with a separate compression ring. It can
be appreciated that the retention mechanism described will work well with other shapes
of prongs than those illustrated, which are flat blade type prongs. For example, the
retention mechanism will work well with round prongs such as used in NEMA 5-15 and
other plugs. Only minor changes are needed such as shaping the end of the toggle where
it contacts the round prong to have a suitable matching shape and thickness to optimize
how the force is applied to the material of the prong. This is desirable, since many
round prongs are formed of tubular, not solid material and therefore can be deformed
or crushed by too much force applied to too small an area of the material they are
made of. Similarly, the bottom of the saddle and/or the electrical contact could be
shaped to spread the clamping force more evenly on to the round prong and/or an insert
between the saddle and the terminal could be used for this purpose. Although the embodiment
of Figures 14A-15B has been illustrated and described in relation to a conventional
cord cap, it will be appreciated that similar structure can be incorporated into other
types of receptacle devices including, for example, the structure described in PCT
Application
PCT/US2008/57140 entitled, "Automatic Transfer Switch Module,".
[0057] By utilizing a clamping mechanism (e.g., the spring prong retainer 40) that captures
the ground prong of the plug 50 only, the safety of the receptacle 20 may be greatly
improved. In this regard, the effect of the application of various electrical potentials
to clamping mechanism of the assembly is avoided, which may simplify the manufacturing
of the receptacle, as well as improve its overall safety.
[0058] Figures 4A-4C illustrate a locking device 60 for providing a locking feature for
a standard cord-cap receptacle. As shown in Figure 4A, the locking device 60 includes
a top holding member 62 and a bottom holding member 64 for positioning the locking
device 60 onto a standard receptacle. The locking device 60 also includes a portion
66 that couples the holding member 62, 64 in relation to each other to provide a secure
attachment to a receptacle. The locking device 60 also includes a clamping mechanism
68 that is coupled to a pivot 70. The operation of the clamping mechanism 68 is similar
to that of the clamping mechanism 12 illustrated in figures 1A-1C. It can be appreciated
that the other clamping mechanisms described earlier could also be employed. As described
earlier some of these eliminate the need to provide a separate release and could optionally
provide a factory and/ or user adjustable release tension feature. The locking device
60 may also include a release mechanism 72 that is operative to enable a user to disengage
the clamping mechanism 68 when it is desired to remove a receptacle from a plug.
[0059] Figure 4B illustrates the locking device 60 positioned onto a standard receptacle
80. To facilitate the installation of the locking device 60, the holding members 62
and 64 may be made of an elastic material such that a user may bend them outward and
position the device 60 onto the receptacle 80. For example, the holding members 62,
64 may be made of plastic. Further, as shown, the holding members 62, 64 are shaped
such that once installed onto the receptacle 80, the device 60 is not easily removed
without a user deforming the holding members 62, 64. That is, the holding members
62, 64 may be shaped to closely fit onto standard receptacle, such that normal movements
will not disengage the device 60 from the plug 80.
[0060] Figure 4C illustrates the operation of the locking device 60 when the receptacle
80 is mated with a standard plug 84. The ground prong 86 of the plug 84 passes through
an aperture in the clamping mechanism 68 and into the receptacle 80. If a withdrawing
force tending to break the mated connection is applied to either the cord of the standard
plug 84 or the cord of the receptacle 80, the clamping mechanism 68 will rotate, causing
it to grip the ground to prong of the standard plug 84, thereby maintaining the electrical
connection. If the user desires to break the connection, the user may engage to release
element 72, which is operative to maintain the clamping mechanism 68 in a substantially
perpendicular position relative to the ground prong 86, thereby permitting the prong
86 of the standard plug 84 to be withdrawn from the receptacle 80. It should be appreciated
that although one particular embodiment of a locking device 60 has been illustrated,
there may be a variety of ways to implement a locking device that may be retrofitted
to a standard receptacle that uses the techniques of the present disclosure.
[0061] Figure 5 illustrates an embodiment of a standard duplex locking receptacle 100. In
this embodiment, clamping mechanisms 112 and 114 are integrated into the receptacle
100. The top portion of the receptacle 100 includes sockets 102, 104 for receiving
the prongs 128, 130, respectively, of a standard plug 126. Similarly the bottom portion
of the receptacle 100 includes sockets 106, 108 for receiving a second standard plug.
The clamping mechanisms 112, 114 are each pivotable about the pivots 116, 118 respectively.
Further the receptacle 100 also includes release elements 120, 122 that are operative
to permit a user to break the connection when desired. The operation of the clamping
mechanism 112, 114 is similar to that in previously described embodiments. That is,
in response to a force tending to withdraw the plug 126 from the receptacle 100, the
clamping mechanism 112 rotates in the direction of the plug 126, and engages the ground
prong 130, preventing the mated connection from being broken. If a user desires to
intentionally removed the plug 126 from the receptacle 100, the user may activate
the release mechanism 120 and withdraw the plug 126. It can be appreciated that the
other clamping mechanisms described earlier could be employed in a standard duplex
locking receptacle. As discussed earlier, some of these eliminate the need to provide
a separate release mechanism and could optionally provide a factory and/or user adjustable
release tension feature.
[0062] Figures 6A-6B illustrate side views of a receptacle 150 that includes a cam lock
152 for locking the prong 162 of a plug 160 to preserve a mated connection between
the receptacle 150 and the plug 160. Figure 6A illustrates the receptacle prior to
the insertion of the plug 160, and the cam lock 152 may hang freely from a pivot 153.
In this regard, an end of the cam lock 152 is positioned in the opening of the receptacle
150 that is adapted for receiving the prong 162 of the plug 160.
[0063] Figure 6B illustrates the mated connection of the plug 160 and the receptacle 150.
As shown, in the mated position the prong 162 has deflected the cam lock 152 about
the pivot 153, causing the cam lock 152 to be angled away from the plug 160 and abutted
with the prong 162. Thus, when an axial strain is applied to the plug 160 or the receptacle
150, the friction between the cam lock 152 and the prong 162 will tend to force the
cam lock 152 downward toward the prong 162, which functions to retain the plug 160
in its mated position. If a user desires to intentionally remove the plug 160 from
the receptacle 150, they may press the actuating mechanism 154, which may be operable
to rotate the cam lock 152 out of the way of the prong 162, thereby enabling the user
to freely withdraw the plug 160 from the receptacle 150. It should be appreciated
that the cam lock 152 and the actuating mechanism may be constructed from any suitable
materials. In one embodiment, the cam lock 152 is constructed out of metal, and the
actuating mechanism 154 is constructed from an insulating material, such as plastic.
[0064] Figures 7A-7D illustrate a device 170 that may be used to secure a mated connection
between a plug and a receptacle. As shown, the device 170 includes a top surface 173,
a bottom surface 175, and a front surface 171. The three surfaces 171, 173, 175 are
generally sized and oriented to fit around the exterior of a standard receptacle 178
at the end of a cord (i.e., a cord cap). The top and bottom surfaces 173 and 175 each
include hooks 174 and 176, respectively, that are used for securing the device 170
to the receptacle 178 (shown in Figure 7D). The operation of the hooks 174 and 176
is described herein in reference to Figure 7D, which shows a side view of the device
170 when it is installed around the exterior of the receptacle 178. The hooks 174,
176 may be bent inward towards each other, and wrapped around an end 179 of the receptacle
178 to secure the device 170 to the receptacle 178. The other end of the receptacle
178 (i.e., the end with the openings 181 for receiving the prongs of a plug) may be
abutted with the face surface 171 of the device 170.
[0065] The device further includes tabs 172 that are used to securing the prongs of a plug
in place. The operation of the tabs 172 is best shown in Figure 7B, which illustrates
the device 170 when installed over the prongs 182, 184 of a plug 180. The plug 180
may be any plug that includes prongs, including typical plugs that are disposed in
the back of electrical data processing equipment. As shown, when the device 170 is
installed by sliding it axially toward the plug 180, the tabs 172 deflect slightly
toward the ends of the prongs 182, 184. In this regard, if an axial force that tends
to withdraw the device 170 from the plug 180 is applied, the tabs 172 will apply a
downward force against the prongs 182, 184. Since the openings in the device 170 are
only slightly larger than the prongs 182, 184, this downward force retains the prongs
182, 184 in their position relative to the device 170. Further, because the device
170 may be secured to a standard receptacle as illustrated in Figure 7C, the tabs
172 prevent the connection between the receptacle 178 and the plug 180 from being
broken. The device 170 may be constructed of any suitable non-conductive material.
In one embodiment, the device 170 is constructed from a semi-rigid plastic. In this
regard, the device 170 may be a single use device wherein a user must forcefully withdraw
the installed device 170 from the prongs 182, 184 of the plug 180, thereby deforming
the plastic and/or breaking the tabs 172. It should be appreciated that if a user
desired to unplug the receptacle 178, they may simply unwrap the hooks 174, 176 from
the end 179 and separate the mated connection, leaving the device 170 installed on
a plug.
[0066] Figure 8A illustrates a plug 190 that includes a locking mechanism prior to insertion
into a receptacle 210. As shown in a simplified manner, the receptacle 210 includes
recesses 212 and 214. Most standard receptacles include a recess or shoulder inside
the openings that are adapted to receive the prongs of a plug. This recess may be
present due to manufacturing requirements, such as the molding process used to manufacture
the receptacles. Further, the need to include various components (e.g., electrical
connections, screws, etc.) in the receptacles may cause the need for the small recesses.
If the recesses are not already present, they could be designed into the receptacle.
[0067] The plug 190 uses the recess 214 to assist in creating a locking mechanism. As shown,
a hollow prong 194 (e.g., the ground prong) of the plug 190 includes a toggle 196
that is attached via a pivot to the 193 inner portion of the prong 194. A spring 198,
piston 199, and an actuating mechanism 200 function together to enable the toggle
196 to be oriented in a lock configuration (shown in Figure 8B), and a release configuration
(shown in Figure 8C). In one embodiment, the spring 198 acts to bias the tab 198 in
the release position, which may be a substantially aligned with horizontal position
inside the prong 194. Furthermore, the actuating mechanism 200 may be operable to
rotate the toggle 196 into the unlock position (shown in Figures 8C) where the toggle
196 retracts into the prong 194 at an angle substantially parallel to the body of
the prong 190. A user may control the actuating mechanism 200 through a control switch
202, which may be positioned on the front of the plug 190.
[0068] Figure 8B illustrates the plug 190 when in a mated position with the receptacle 210.
As shown, the tab 196 has been placed in the lock position by the pressure asserted
by the spring 198 and piston 199. In this configuration, the tab 196 will resist any
axial force that tends to withdraw the plug 190 from the receptacle 210. This is the
case because the recess 214 acts as a stop for the tab 196. Therefore, the plug 190
may be securely fastened onto the receptacle 210. Figure 8C illustrates when a user
desires to remove the plug 190 from the receptacle 210, they may depress the control
switch 202 on the front of the plug 190, which causes the actuating mechanism 200
and the spring 198 to rotate the tab 196 into the release position.
[0069] Figures 9A-9B illustrate another embodiment of a plug 220 that includes a divergent
spring tip locking mechanism prior to insertion into a receptacle 240. Similar to
the plug 190 shown in Figures 8A-8B, the plug 220 may be adapted to work with the
standard receptacle 240 that includes recesses 242 and 244. The plug 220 may include
a hairpin spring 226 that is disposed inside a hollow prong 224 (e.g., the ground
prong). In a release position, the ends 227 of the spring 226 are disposed inside
of the prong 224 and adjacent to openings in the prong 224. The plug 220 may further
include an actuating mechanism 228, couple to a control switch 230 on the front of
the plug 220, for biasing the spring 226 into a lock position, where the ends 227
of the spring 226 protrude outside of openings in the prong 224 (see Figure 9B).
[0070] Figure 9B illustrates the plug 220 when installed into the standard plug 240. As
shown, the actuating mechanism 228 has been moved axially toward the spring 226 into
the standard receptacle 240, causing the ends 227 to spread apart and out of the openings
in the prong 224. The openings of the prong 224 are aligned with the recesses 242
and 244 such that the ends of the spring 226 are disposed in the recesses 242 and
244 when in the lock position. Thus, as can be appreciated, when an axial force that
tends to withdraw the plug 220 from the receptacle 240 is applied, the ends 227 of
the spring 226 are pressed against the recesses 242 and 244, which prohibits the prong
224 from being removed from the receptacle 240. When a user desires to remove the
plug 220 from the receptacle 240, they may operate the control switch 230 which causes
the actuating mechanism to axially withdraw from the spring 226. In turn, this causes
the ends 227 of the spring 226 to recede back into the prong 224, such that the user
may then easily remove the plug 220 from the receptacle 240.
[0071] Figures 10A and 10B show a locking electrical receptacle 1000 according to a further
embodiment of the present disclosure. The receptacle 1000 is generally similar in
construction to the structure of Figures 2A-2B. In this regard, the illustrated receptacle
1000 includes an end cap formed from an outer lock release grip 1002 that is slideably
mounted on an inner contact carrier module 1004. The inner contact carrier module
carries a number of sockets or receptacles generally identified by reference numeral
1006. The illustrated receptacle 1000 further includes cord strain relief 1010 and
spring prong retainer 1008.
[0072] Figure 10B shows a perspective view of the spring prong retainer 1008. As shown,
the retainer 1008 includes a number of gripping tabs 1012 for gripping the contact
carrier module 1004. In this regard, the gripping tabs 1012 may be embedded within
the molded contact carrier module 1004 so as to more firmly secure the retainer 1008
to the carrier module 1004. Alternatively, the tabs 1012 may be pressed into the carrier
module 1004 or attached to the module 1004 by an adhesive or the like. In this manner,
the tabs 1012 assist in securing the spring prong retainer 1008 to the contact carrier
module 1004 and maintaining the relative positioning between the spring prong retainer
1008 and the contact carrier module 1004. It will be appreciated from this discussion
below that this relative positioning is important in assuring proper functioning of
the locking mechanism and controlling the release tension. The locking electrical
receptacle of 1000 otherwise functions as described above in connection with Figures
2A-3B.
[0073] Figures 11A and 11B show a further embodiment of a locking electrical receptacle
1100. Again, the receptacle 1100 is generally similar to the structure described above
in connection with Figures 2A and 2B and includes an outer lock release grip 1102,
and inner contact carrier module 1104 including a number of receptacles 1106, and
a cord strain relief structure 1110. The illustrated embodiment further includes a
spring prong retainer 1108 incorporating strain relief structure. It will be appreciated
that the locking mechanism of the present disclosure can result in significant strain
forces being applied to the end cap in the case where large tension forces are applied
to a plug against the locking mechanism. Such forces could result in damage to the
end cap and potential hazards associated with exposed wires if such forces are not
accounted for in the end cap design.
[0074] Accordingly, in the illustrated embodiment, the spring prong retainer 1108 includes
strain relief structure for transmitting such strain forces directly to the power
cord. Specifically, the illustrated spring prong retainer 1108 is lengthened and includes
a cord grip structure 1114 at a rear end thereof. The cord attachment grip structure
1114 attaches to the power cord or is otherwise connected with a crimping band 1112
that can be secured to the power cord via crimping and/or welding, etc. or the like.
In this manner, strain forces associated with operation of the spring prong retainer
1108 to grip prongs of a plug are transmitted directly to the power cord.
[0075] Various characteristics of the locking electrical receptacle of the present disclosure
can be varied to control the release stress of the locking electrical receptacle.
In this regard, the geometry, thickness, material qualities and detail shaping of
the gripping component can be used to control the release tension of the locking mechanism.
As an example, increasing the thickness and/or stiffness of the material of the gripping
component increases the release tension of the locking mechanism.
[0076] The geometry of these spring prong retainers may also be varied to provide improved
safety and performance. Figure 12 shows on example in this regard. The illustrated
spring prong retainer 1200, which may be incorporated into, for example, the embodiments
of Figures 2A-2B, 10A-10B, or 11A-11B, includes a narrowed neck portion on 1202 between
the flex point 1204 of the spring prong retainer and the prong engagement opening.
This neck portion may provide a number of desirable functions. For example, the neck
portion 1202 maybe positioned to provide greater clearance between the spring prong
retainer 1200 and the other prongs of plug. In addition, the narrow portion 1202 may
be designed to provide a defined breakpoint in the case of structural failure. That
is, in the event breakage occurs due to stress or material fatigue, the neck portion
1202 provides a safe failure point that will not result in electrical hazards or failure
of the electrical connection.
[0077] It can be appreciated that all of the retention mechanisms described herein that
can have their release tension changed by varying their design parameters, can have
a release tension that is coordinated with the receptacle design or a standard or
specification so as to ensure that the cord cap or receptacle will not break resulting
in a potentially hazardous exposure of wires. Thus, for example, it may be desired
to provide a release stress of forty pounds based on an analysis of an end cap or
receptacle structure, a regulatory requirement, or a design specification. The locking
mechanism may be implemented by a way of a spring prong retainer as shown, for example,
in Figures 2A-2B, 10A-10B and 11A-11B. Then, the material and thickness of the spring
prong retainer as well as the specific geometry of the spring prong retainer may be
selected so as to provide a release stress of 40 lbs. The locking mechanism with a
release stress of 40 lbs can also be implemented in the toggle and saddle mechanism
as shown, for example in Figures 14A-14D and 15A-15B. The values of these various
design parameters may be determined theoretically or empirically to provide the desired
release point.
[0078] Figures 16A-16B illustrate an embodiment of a retention mechanism for securing a
mated electrical connection that may be included in a secure connection of the present
disclosure. In Figures 16A-16B, the top portion represents a top view of a mated plug
and receptacle 100 and a retention mechanism 1020, while the bottom portion represents
a perspective view. The electrical prongs 1030 may be two or more in number (e.g.,
an IEC 320 plug, a NEMA 5-15, or the like) and may be various sizes and shapes. Further,
the plug and receptacle 1000 may be the plug and receptacle of a standard outlet (e.g.,
an IEC 320 cord cap, or the like). The plug also includes the retention mechanism
1020. The design of the secure retention mechanism 1020 is such that a simple slide
in and then secure the connection technique is utilized. Referring next to Figure
17A, the plug and receptacle are shown mated but prior to the connection being secured.
This embodiment is one that the user must manually elect to secure, as described earlier.
[0079] Figures 17A-17B illustrates the plug 2010 when inserted into the receptacle 2020.
As shown, the plug and receptacle are in a mated, but not yet secured position. The
manual actuation nut 2030 is twisted by the user to secure and release the connection.
The nut can have an optional ratcheting mechanism as described earlier, this is not
shown. The outer shell 2040 is pressed into the elastomer 2050 by the action of the
nut 2030, when the nut is tightened. The outer shell will compress the elastomer when
tightened and will be pushed back by the expansion of the elastomer when the nut is
loosened. Optionally, the shell can be positively attached to the nut using an appropriate
mechanism (such as a mushroom ended pin going through a semi-circular slot in the
nut) to insure that it is positively retracted when the nut is loosened. This is an
optional construction that is not shown. The blow-up portions of the diagram, 2100
and 2200 show two different possible instantiations of this part of the mechanism.
Detail 2030 shows the shape of the area of the mechanism where the elastomer is compressed
as substantially rectangular. Detail 2040 shows the shape of the area of the mechanism
where the elastomer is compressed in a shape that utilizes inclined ramps to compress
the elastomer. As will be appreciated, the materials and detailed geometry of both
2100 and 2200 can be varied to optimize their function as described earlier.
[0080] Figures 18A-18B illustrates the plug 3010 when inserted into the receptacle 3020.
As shown, the plug and receptacle are in a mated and secured position. The manual
actuation nut 3030 has been twisted by the user to secure the connection. The outer
shell 304 is being pressed into the elastomer 3050 by the action of the nut 3030,
which is tightened down. The outer shell is compressing the elastomer, which in turn
is pressed tightly against the wall 3060 of the abutting receptacle 3020. This is
shown in more detail in the blow-up portions of the diagram, 3100 and 3200. The outer
shell 3040 will be pushed back by the expansion of the elastomer when the nut 3030
is loosened. Optionally, the outer shell 3040 can be positively attached to the nut
using an appropriate mechanism (such as a mushroom ended pin going through a semi-circular
slot in the nut) to insure that it is positively retracted when the nut is loosened.
This is an optional construction that is not shown. Detail 3100 shows the shape of
the area of the mechanism where the elastomer is compressed as substantially rectangular.
Detail 3200 shows the shape of the area of the mechanism where the elastomer is compressed
in a form that utilizes inclined ramps to compress the elastomer. As will be appreciated,
the materials and detailed geometry of both 3100 and 3200 can be varied to optimize
their function as described earlier.
[0081] Figures 18C illustrates a blowup of another possible instantiation of the disclosure.
The tabs 3300 located on the outer shell 3310 are driven axially forward by the action
of the nut 3340, when it is tightened down. The tabs 3300 push forward over ramps
3320 in the part of the assembly that is inserted into the matching receptacle. The
example in Fig. 18C shown is a male C13, but the same concepts and mechanisms work
with a female C13 as shown in Fig. 18D. The only substantial difference in construction
between the male C13 shown in Fig. 18C and the female C13 shown in Fig. 18D is how
the electrical contacts are located, in the female version a contact carrier 3480
(which is usually a safety agency approved part) is molded into the cordcap. The outer
shell 3470 can be overmolded onto the contact carrier or made as a separate part that
snaps over the contact carrier, which is the construction shown in Fig. 3D. Other
construction methods are possible. The geometry, material, location, number and mechanical
action of the tabs 3300, 3400 and ramps 3320, 3420 can be varied to insure that the
area of maximum pressure exerted by the ramps contacting the mated receptacle is located
as desired. This can be important to maximize the retention force and insure that
the receptacle can withstand the force applied by the tabs 3300, 3400 without damage.
The tabs 3300, 3400 can be one or more in number, and can be located to maximize the
retention force of the mechanism. They may or may not be located to oppose each other,
which can be used to insure that the force applied to the receptacle maximizes the
retention force. As shown, the tabs 3300, 3400 would tend to apply force to the receptacle
such that the walls of the receptacle are stressed in tension, which can be desirable,
depending on the material of the receptacle. The surface of the tabs 3350 ,3450 that
contacts the wall of the mated receptacle can be made of one or more materials with
suitable mechanical and frictional characteristics. An example of a possible instantiation
would be to make the outer shell 3310, 3410 of a harder, mechanically strong material
and then coat or the tab surfaces 3350, 3450 with a high friction coefficient elastomer.
This could be economically done via a coinjection ("sandwich") molding process, for
example. As can appreciated, in reaction to a withdrawal force 3385,3485 applied to
the cord 3380, 3480, the retention mechanism as shown in Fig. 18C, 18D will transmit
the force via the cord 3380, 3480 to the end of the cordcap 3390, 3490. This will
compress elastomer injection molded materials that are commonly used to make electrical
cords, resulting in the end of the cordcap being moved slightly closer to the outer
shell 3310, 3410 which moves the tabs 3300, 3400 farther up the ramps 3340, 3440 which
presses the contact area of the tabs 3350, 3450 into closer and closer contact with
the walls of the receptacle, causing the frictional interlock between the plug and
the receptacle to increase. Thus, the very force 3385, 3485 that tends to withdraw
the plug from the receptacle acts to engage the retention mechanism to frictionally
interlock with the walls of the receptacle, thereby preventing the withdrawal of the
plug, and maintaining the electrical connection of the mated assembly. The geometry,
material and mechanical action of the tabs 3300, 3400 and ramps 3320, 3420 can be
also be varied to provide a programmable release mechanism by limiting the force applied
to the walls of the mated receptacle and thus the frictional interlock between the
contact surfaces of the tabs 3350, 3450 and the walls of the mated receptacle. Limiting
the frictional interlock limits the maximum force the secured connection can resist.
Once that level of force is applied, the plug and receptacle will separate. As discussed
earlier, the level of the maximum force can therefore be specified to prevent damage
to the plug and receptacle and/or meet an applicable standard and as also discussed
earlier a range of retention force values that can be adjusted by the user via the
action of the nut 3340, 3440.
[0082] Figures 18E-18K illustrate a possible instantiation of the invention and represents
an alternate locking method for an IEC-13 receptacle utilizing a novel retention mechanism.
It is comprised primarily of three main components associated with the gripping of
this connector to a mating type connector, e.g. IEC-14. It should be noted that this
mechanism is not limited to the IEC series connectors, but could be adapted to a variety
of connector mating applications including those that utilize a shield barrier outer
shell on the receptacle. In the case of such shield barrier receptacles, gripping
can be accomplished by using the shield barrier as a frictional element against the
wall of the mating receptacle and is independent of the electrical conduction methods
utilized within the connectors themselves.
[0083] Observing Figure 18E, the inner core of the connector 1 is comprised of a molded
assembly that is very similar to traditional IEC-13 (or other standards) cord-cap
receptacles (female end) with regards to dimensions and electrical interface components.
It differs in that dielectric over-mold has two rectangular holes 3551 through the
outer shell penetrating to the interior of the shell. In addition, a locking tab shuttle
2 made of a suitable material provides the locking tabs 3553 and structure for transferring
force from a locking nut 3 into the interior of the shell area of the inner core 1
via holes 3551.
[0084] The locking to a mating connecter is achieved by the tabs 3553 being driven by the
nut and thereby wedged between the top and bottom outer surface of the mating connector,
and the top and bottom inside surfaces of the inner core shell 1. When it is desired
to release the connection, the nut 3 is loosened which withdraws the tabs 3353 by
positive retraction. This is accomplished by the engagement collar 3555 on the nut
3 which turns in the slot 3554 in the locking tab shuttle 2 pulling out the tabs 3553.
Other means can be used to attach the nut 3 to the locking tab shuttle 2, an example
is shown in Figure 25. This method of locking provides good gripping with a programmable
release force. Careful selection of the shapes, geometry and materials used allow
the maximum retention force to be limited to a desirable range of values. Additionally
the outer surfaces of the over-mold (for example the outer surfaces that are directly
over the locking tabs 3553 can optionally be coated, textured or otherwise designed
to increase the frictional force between the outer shell 3551 and the mating wall
of the receptacle. The ability to control the release force to a chosen range of values
is a desirable to prevent excessive pulling force from possibly damaging the plug
and cordcap in the mating connection. It can also be useful to satisfy certain agency
approvals. In addition, this method is simple to manufacture and has a minimum of
moving parts.
[0085] Referring to Fig. 18F, cross-sections of two primary parts are shown, a top view
of the traditional cord-cap plug (male connector), 1 and a top view of the mating
cord-cap connector (female receptacle) 2. The plug 1 is described as part of the description
of the method of securing the electrical connection, but a key point is that the plug
can be a standard un-modified plug. Only the mating receptacle 2 differs from traditional
standards and is unique. This means that the invention is applicable to the very large
installed population of standard plugs, such as are used in plugstrips in data centers.
IEC C14 plugstrips are very popular for distribution of 200V+ electrical service worldwide.
The traditional plug is comprised of three major components as shown in Fig. 18F,
the over-mold dielectric 3561, a connecting cord containing the necessary electrical
conductors 3562, and the electrical mating connector pins 3563. This example is of
a traditional IEC-14 type plug, but could be other types utilizing an outer pin dielectric
barrier 3569. This outer pin barrier 3569 is generally concentric around the pins
3563, and will be the object of the gripping by the mating receptacle when applied.
[0086] The focus of this application is the receptacle assembly 2 which includes a core
with an outer shell 3564, a shuttle 3565 which includes, as a part of it, locking
tab 3567 one of which is shown. This is the top view so the outline of the tab can
be observed, but two tabs exist, one on the top of the connector and one on the bottom,
where each is an integral part of the molded shuttle components in the illustrated.
The tabs shown are a preferred instantiation, but the methods described can work with
other tab numbers, shapes, and locations. The core 3564 has also molded onto it some
type of threads 3570 which engage with a locking nut 3566. This threaded nut works
against the threads of the core 3564, to apply force to the movable shuttle 3565 and
transmit axial force to the tabs 3567.
[0087] Fig. 18G represents a cross section side view of the aforementioned components in
Fig. 18F. This view shows more clearly the relationship of the top and bottom locking
tabs 3567, and that they are part of the shuttle 3565. In Fig. 18G, the receptacle
assembly 2 is shown with the locking nut 3570 turned to the locked position, the shuttle
3565 pushed forward, and the locking tabs 3567 fully inserted into the shell and core
3564. Fig. 18H is an expanded cross section side view of the receptacle assembly 2.
In this view it is more clearly shown the penetration of the tabs 3567 through the
holes 3551 in the core and shell 3564. The holes 3551 have a tapered entrance 3571
into the cavity of the core and shell 3564 that causes the tabs 3567 to be pushed
towards the centerline when the shuttle 3565 moves from right to left in this example.
This example has the shuttle 3565, and hence the tabs 3567 shown in the release position.
The tabs 3567 are substantially retracted from the cavity thus leaving the area in
that cavity available for insertion of the mating plug's shell. For the purpose of
describing the focus of this application, the non-applicable components of both the
plug and receptacles will not be referenced further. Those components include the
electrical components such as the pins and sockets, and the cords.
[0088] Fig. 18I shows the receptacle assembly of Fig.18F with the locking nut 206 turned
such that it applies axial force forward on the shuttle 3565, which in turn has pushed
the tabs 3567 into the cavity of the core and shell 3564. It is important to note
the relationship of the tabs 3567 and the tapered entrance 3571. The combination of
the taper on the tabs 3567, and the tapered entrance 3571 have caused the tabs 3567
to bend inwards towards the centerline of the assembly. Fig 18J represents the mating
of an un-locked position receptacle 2 with a standard mating plug 1. A detailed blow
up is shown in the lower right that more clearly shows the non-interference of the
locking tabs 3551 with the mating plug barrier shell 3569. When the shuttle 3565 is
retreated as shown, there is little or no contact between the tab 3551, the inner
wall ramp of the core and shell 3571 and the outer surface of the mating plug's barrier
shell 3569.
[0089] Fig. 18K shows the mated and locked condition of the plug 1 and receptacle 2 combination.
The nut 3566 has been turned forcing the shuttle 3565 forward. The detailed blow up
shown in the lower right more clearly shows the new relationship between the tabs
3567, and mating plug barrier shell 3569. When the shuttle 3565 is forced forward
as shown, there is significant contact between the tab 3551, the inner wall ramp of
the core and shell 3571 and the outer surface of the mating plug's barrier shell 3569.
As the locking nut 3566 is further tightened, the radial forces between the tab 151,
the inner wall ramp of the core and shell 3571 and the outer surface of the mating
plug's barrier shell 3569 increase very rapidly due to the force amplification of
the gradual taper of the tab 3567 and the inner wall ramp of the core and shell 3571.
This same action is happening on the opposite side of the plug's barrier shell, and
in the opposing direction on that side. These opposing forces help to maintain centering
of the plug 1 in the receptacle 2.
[0090] To summarize, what is shown is an alternate method of securing (locking) two mating
connectors utilizing friction only. The description of the mechanical characteristics
of the receptacle demonstrate a mechanism for securing (locking) the receptacle to
a standard and un-modified mating plug of the same standard.
This method of securing an electrical connection can be easily adapted to deliver
various release tension ranges as necessitated by application or by regulating agencies.
Minor modifications to the shape, placement and geometry of the tabs, tapered openings
and thread pitch all can have various effects on the securing force and the types
of force necessary to dis-connect a "locked" mating of the plug and receptacle. The
simple nature of this design is robust and yet easy to manufacture. The reduced parts
count, and use of all injection-moldable materials reduces manufacturing cost.
[0091] Figures 19-22 illustrate the operation of another embodiment of a mechanism for securing
a mated electrical connection that may be included in a secure connection of the present
disclosure. This embodiment is one that automatically secures itself in response to
a force 6070 that would tend to pull the connection apart. Figures 20-22 represents
top views of the retention mechanism in the states of: 1) fully inserted 5000, 2)
fully inserted under tension 6000, 3) being released 7000. Figure 19 illustrates the
plug and receptacle and the elements of retention mechanism. Figure 20 illustrates
the connection after the plug has been inserted into the receptacle but no force has
been applied that would tend to pull the connection apart. Figure 21 illustrates the
operation of the retention mechanism 6000 in reaction to a force on the plug 601 that
tends to withdrawal the plug 6010 from the receptacle 6020. In reaction to a withdrawal
of the plug 6010, the retention mechanism as shown in detail blowup 6100 via the action
of the inclined ramp 6040 forces the elastomer 6050 into closer and closer contact
with the walls of the receptacle 6060, causing the frictional interlock between the
plug 6010 and the receptacle 6020 to increase. Thus, the very force 6070 that tends
to withdraw the plug 6010 from the receptacle 6020 acts to engage the retention mechanism
6000 to frictionally interlock with the walls of the receptacle 6060, thereby preventing
the withdrawal of the plug 6010, and maintaining the electrical connection of the
mated assembly. The retention mechanism 6000 may be constructed of any suitable material
as described earlier. Figure 22 illustrates the operation of the retention mechanism
during release of the secure connection. When the user desires to release the connection,
they can grasp and pull the outer shell 7030 which will retract, pulling 7070 the
elastomer 7040 back down the ramp 7050, via the extension of the outer shell 7060,
uncompressing the elastomer 7040 thus releasing the connection.
[0092] Figures 23-24 illustrate the operation of another embodiment of a mechanism for securing
a mated electrical connection that may be included in a secure connection of the present
disclosure. This embodiment is one that automatically secures itself in response to
a force that would tend to pull the connection apart. Figure 23 illustrates a side
top of the plug 8000 that incorporates the secure mechanism, and side view 8010 and
perspective views 8020 of a typical standard receptacle. The receptacle has fingers
8030 that are used to secure the receptacle 8020 when it is snapped into a panel.
These fingers 8030 are typically provided in individually molded snap-in receptacles
8020 and typically provided in molded models of receptacles that provide 2, 3 or more
receptacles in one molded unit for snap-in insertion into a plugstrip. The fingers
8030 splay when the receptacle 8020 is inserted, leaving an opening in the body of
the receptacle 8020. Where the fingers are not provided, the manufacturer could alter
the molding to insure they or a similarly shaped and located slot or hole are provided
in every model of individual or multiple receptacle, at low cost with little or no
impact on regulatory body approvals, making it easy and inexpensive to offer. The
plug 8000 has tabs 8040 (that optionally can be shaped as hooks) that will expand
and insert themselves into the openings in the body of the receptacle 8020 when the
plug 8000 is inserted into the receptacle 8020. The ends of the tabs 8040 can be located
and shaped so that they can insert themselves into and transfer forces that would
tend to pull the connection apart to the walls of the receptacle, but not pass through
the opening in the wall of the receptacle 8020. This insures that the tabs 8020 cannot
become wedged by the walls of the receptacle in response to a force that would tend
to pull the connection apart and therefore separate the plug 8000 and receptacle 8020.
This shaping of the tabs 8020 insures that the secure connection will function properly
and always release when desired. To release the connection the user grasps the outer
shell 805, and pulls it back to pull the plug 8000 out of the receptacle 8020.
[0093] Figures 24a-24e represents top views of the retention mechanism with an electrical
contact prong in the states of: 1) partially inserted Fig. 24a, 2) being inserted
but not yet secured Fig. 24b, 3) fully inserted and secured 9020 Fig. 24c, 4) fully
inserted while being released 9030 Fig. 24d, 5) being removed, thus breaking the connection
9040 Fig. 24e. As described above, and demonstrated in Figures 24a-24e the plug 8000
has tabs 8040 (that optionally can be shaped as hooks) that will expand and insert
themselves into the openings in the body of the receptacle 8020 when the plug is inserted
into the receptacle 8020. To release the connection the user grasps the outer shell
8050, and pulls 8060 it back to pull the plug 8000 out of the receptacle 8020 as demonstrated
in Figure 24d and Figure 24e. The outer shell 8050 is equipped with suitably shaped
substantially rectangular openings for the tabs 8040 to extend through and when the
outer shell 8050 is pulled 8060 back by the user, the edge 8070 of the rectangular
opening that is closest to the front of the male plug will depress the tabs 8040,
freeing the plug 8000 to disconnect from the receptacle 8020. The retention mechanism
may be constructed of any suitable material as described earlier. It should be noted
that this embodiment of the mechanism could easily be combined with the earlier versions
described that use a user activated manual retention mechanism. This instantiation
would use the actuation nut described earlier to control the position and movement
of the outer shell. The release position of the actuation nut would position the outer
shell to depress the tabs, preventing their engagement with the receptacle, but not
preventing the plug from being inserted into or removed from the receptacle. The secure
position of the actuation nut would allow the tabs to engage with the receptacle,
securing the connection. This version might be useful in some circumstances.
[0094] Figures 26A-C depict another possible method to secure cords to plugstrips. The locking
mechanism has been incorporated into the plugstrip, so that every cord is locked at
once and all can be released at one time. Fig. 26J shows an multiple electrical outlet
assembly 4040 comprised of 12 ea., National Electrical Manufacturers Association (NEMA)
type 5-15 receptacles (other receptacle types could be used, the 5-15 type is used
as an example) oriented in a line and assembled into a narrow profile long "strip".
This configuration is commonly utilized in electronic equipment racks, and is often
referred to as a plugstrip, and will be referred to hereinafter as such. Any number
of receptacles, from one to any practical limit, can be manufactured using this method.
The plugstrip that is the object of this disclosure is unique in that it incorporates
a locking feature for the purpose of securing the plugs of electrical cords that are
to be attached to the plugstrip. The locking or un-locking of the receptacles to the
attached electrical plugs is accomplished by an operation of rotating a hex socket
screw 4021 on the front of the panel with a small tool. This does not necessarily
need to be a hex socket, it could be a knob or handle integrated into (or separate
from) the assembly, or some other means of actuating the internal mechanism. It could
be a proprietary connector with matching tool, knob, or lever, etc. to restrict the
ability to unlock and relock the plugstrip to authorized personnel. It could be a
motor or solenoid driven locking mechanism controlled either locally (by a button
or switch or secure key-actuated switch or secure digital authentication data fob
or secure code keypad such as have been used for car doors, for example or digital
passkeys, ID cards, or other suitable physical access control mechanisms) or a remotely
controlled motor drive. The remote control could be accomplished via any suitable
communications mechanism with or without security features as needed, for example
over the Internet, an internal data network, via wireless network, (any of which could
be implemented as a secure connection, using encryption, authentication, tokens, etc.)
or any other suitable means.
A unique concept of the disclosure is the ability to lock or unlock all of the receptacles
from attached plugs by a single, simple operation. In addition, the design allows
for a predictable pull out force (programmable release) to extract any attached plug,
when the assembly is in the locked position. This may be necessary to meet Agency
requirements, such as Underwriters Laboratories (UL). The design allows for a wide
variation in manufactured tolerances of the attached plugs. In addition, the design
of this assembly allows for lowered cost of manufacturing and higher reliability due
to the simplicity of the design. This design can be adapted to a variety of plug types
and is not limited to the example of NEMA type 5-15 plugs.
Detailed description:
[0095] A key design feature of the locking assembly is a unique prong capture mechanism
that can be assembled in any length with any number of capture points that will correspond
to the number of receptacles the plugstrip is supplying. Fig. 26A outlines three basic
components of each prong capture assembly. These assemblies will be located at each
receptacle, in combination of at least one assembly per receptacle, but can, and will
likely, be applied to every prong capture location of any one receptacle, as well
as all of the receptacles. The assemblies must be kept separate for each of the electrical
conductors for electrical isolation reason. The components shown in Fig. 26A are all
metallic in nature and most likely be fabricated of a good conducting metal such as
brass, beryllium copper, or other reasonably tensile strong material, but is not limited
to those materials. The primary electrical prong receiver 4001 is shown at the left
of the figure. It is comprised of a machine stamped and die-formed piece. The prong
wipes 4010 are formed from the base stamped metal and are rolled inward in a manner
commonly practiced in the industry to provide an aperture for the mating prong to
enter and exit reasonably easily, but with very secure electrical connection to the
mating prong. A hole in the stamping 4012 is located behind the electrical wipes 4010
to allow the prong of the mating connector to fully penetrate the assembly. An additional
hole is punched in the metal 4011 just above the first hole. This hole 4011 will allow
operational room for a spring of an additional component of the finished assembly.
The second component of the grip assembly is the prong bearing stamping 4002 that
performs the function of actually holding the inserted prong when actuated to do so.
It is again an electrically conductive metal and must have some degree of brittleness.
This is necessary since there is an integral spring 4017 formed into the stamping.
Observing the side view of the component, it can be observed that the metal of the
spring 4017 is deflected to the left in an arc. The purpose of this spring will be
discussed later when the assembled components are described. In addition, a hole is
stamped into this component 4015 that allows the prong of the mating plug to penetrate
this stamping, without interference. A third component, the back prong support 4003
is shown, and it is a simple stamping with a hole in it 4020 at the same relative
location as on the prong receiver 4001 at the lower aperture 4012.
[0096] Fig. 26B shows an orthogonal view 4051 and a side view 4052 of the three aforementioned
components 4001, 4002, 4003 into an assembly. It is now apparent why the hole 4011
was necessary in the prong receiver component 4001. The spring 4017 protrusion now
has a place to be without interference. In this view, it can also be observed that
the three lower apertures align to allow penetration by an engaging prong of a plug
to be attached.
[0097] In Fig. 26C, an additional component is shown, the prong and a partial view of a
representative plug with a single prong 4013 and is not part of the completed assembly
of this disclosure but is used to clarify the function of the components in the process
of locking the two pieces 4052, 4053 together. The representative plug and prong 4053
assembly is comprised of a prong 4017 and an insulating carrier 4020. It would be
generally part of a three prong plug assembly, but could be a member of any combination
of prongs. This system will work for any shape prong, simply by matching the shape
of the apertures of the various sub components to the desired prong to be captured.
The prong receiver assembly 4052 is shown in side view and is comprised of the primary
electrical prong receiver 4001, the prong bearing stamping 4002, and the back prong
support 4003. The electrical prong wipe 4010 is not yet engaged by the mating prong
4017 at this time.
[0098] Fig. 26D shows the electrical plug 4053 fully entered into the prong receiver assembly
4052. The aligned apertures of the three components 4001, 4002, 4003 allow the insertion
of the prong 4017 through them and into the electrical wipes 4010. At this point,
the three apertures are essentially aligned and allow the prong 4017 to pass freely
through them. The spring 4017 is shown in the relaxed state.
In Fig. 26E, the prong bearing stamping 4002 is shown with force being applied in
the down direction. The top of the aperture in this stamping is now bearing down on
the top of the prong 4017. Concurrently, the bottoms of the apertures in primary electrical
prong receiver 4001 and the prong bearing stamping 4002 are applying a counterforce
in the opposite direction to the prong 4017 resulting in a shearing action. Since
the relative strength of the prong is great, the shearing force only acts to capture
the prong, and not damage it. The spring 4017 is represented as being compressed at
this time. This allows a measurable range of motion for the prong bearing stamping
4002 after initial contact with the prong 4017. This is necessary as prong dimensions
change from manufacturer to manufacturer, and the placement of multiple prong receivers
in a line necessitate a means to compensate for minor manufacturing variances. This
spring 4017 also serves to allow a pre-determined level of force to be applied to
the prong 4017 for a given range of vertical deflection of the prong bearing stamping
4002. At this point, the prong is captured and "locked".
[0099] Fig. 26F describes a plurality of the aforementioned prong receiver assemblies 4052
contiguously arranged in a linear configuration. All three components of the 4052
component are replicated in a row on a single set of three stampings. The final multiple
prong capture assembly 4054 is comprised of three metallic components assembled together.
[0100] Fig. 26G illustrates three of the multiple prong capture assembly 4054 arranged beside
each other in a manner that produces the aperture locations of each in compliance
with the arrangement of prongs of a mating plug. This arrangement is not limited to
three conductors, and variations including only one capture plate and two electrical
wipe plates are only one example of the variations possible. At least one capture
plate assembly is necessary to capture a plug. The assembly is the electrical conduction
and capture subassembly 4055.
[0101] Fig. 26H represents one possible method of providing the force to the prong bearing
stampings 4002. Note the hooked ends 4020 of the prong bearing stampings hooked around
the edge of the cam plate 4022. When force is applied to the bearing hole 4023 of
the cam plate 4022, the force will be transmitted to the three prong bearing stamping
hooks 4020. The cam plate 4022 is shaped to allow some side to side motion of the
plate with respect to the prong bearing stamping hooks 4020 to allow for the lateral
action associated with the cam motion. The cam 4024 is held in position in bearings
4025 and is actuated by a receiving hex socket 4027 in this example instantiation.
The cam 4024 and bearings 4025 are carried in a c-frame later described. When the
cam 4024 is rotated via a tool inserted into the hex socket 4027, it rotates eccentrically
about an axis of the bearings 4025. The eccentric motion is transmitted to the cam
bearing 4002 and into the cam bearing receiver 4023, and hence to motion in the cam
plate 4022. Since only a small deflection is necessary, the force amplification of
the force applied to the tool (or knob or other means of turning the cam as previously
discussed) is amplified many-fold, the force necessary to lock all the plugs is maintained
at an easy to achieve level.
[0102] Fig. 26J shows the sub-assembly components, dielectric receptacle faces 4058, the
electrical conduction and capture subassembly 4055, Cam actuator 4056, cam support
c-frame 4057, dielectric separator 4059, and back housing 4050 of an assembled plugstrip
4040 The end caps, cord assembly and electrical attachments are not shown, but are
implied in a final assembly, and are attached by traditional means.
The disclosure has several novel features, among them:
Locking and un-locking of all receptacles simultaneously.
The spring can be manufactured with characteristics resulting in predictable pull-out
tensions for captured plugs. Any practical length and number of receptacles is possible
from one actuation point.
The profile area behind the receptacle face is absolute minimum.
Simple stampings allow lower cost assembly and manufacturing.
A simple twist operation, either by a tool or other means previously discussed, is
all that is necessary to lock and un-lock the assembly.
[0103] The foregoing description of the present disclosure has been presented for purposes
of illustration and description. Furthermore, the description is not intended to limit
the disclosure to the form disclosed herein. Consequently, variations and modifications
commensurate with the above teachings, and skill and knowledge of the relevant art,
are within the scope of the present invention. The embodiments described hereinabove
are further intended to explain best modes known of practicing the disclosure and
to enable others skilled in the art to utilize the disclosure in such, or other embodiments
and with various modifications required by the particular application(s) or use(s)
of the present disclosure. It is intended that the appended claims be construed to
include alternative embodiments to the extent permitted by the prior art.