BACKGROUND
Description of the Related Art
[0001] Electronic locks, like described in
WO2008/034022 e.g., have a number of advantages over normal mechanical locks. For example, electronic
locks may be encrypted so that only a key carrying the correct code will operate the
lock. In addition, an electronic lock may contain a microprocessor so that, for example,
a record can be kept of who has operated the lock during a certain time period or
so that the lock is only operable at certain times. An electronic lock may also have
the advantage that, if a key is lost, the lock may be reprogrammed to prevent the
risk of a security breach and to avoid the expense associated with replacement of
the entire lock.
[0002] One drawback of certain electronic locks is that they use a power supply to function
properly. Typically, locks of this type are unable to use alternating current (AC)
power supplies, such as from wall outlets, due to the inherit lack of security and
mobility of such power supplies. Batteries may be used instead, but batteries may
require constant replacement or recharging. If a battery dies, a lock might fail to
function and thereby create a significant security risk. Electromagnets may also be
employed, but the bulk of such devices in some instances limit the potential use of
electronic locks to larger-scale applications.
[0003] One solution to these drawbacks is to place a power source such as a battery in the
key instead of in the lock. This arrangement allows the lock to remain locked even
in the absence of a power supply. Placing a battery in the key also allows the battery
to be charged more easily because keys are generally more portable than locks.
[0004] When batteries are used in the key, electrical contacts are typically employed to
transfer power and data from the key to the lock. However, electrical contacts suffer
from the drawback of being susceptible to corrosion, potentially leading to failure
of either the key or the lock. Moreover, if separate inductors are used instead to
transfer both power and data, magnetic interference between the inductors can corrupt
the data and disrupt power flow to the lock.
SUMMARY
[0005] In certain embodiments, an electronic lock is provided that includes a locking mechanism
having a bolt and extensions coupled with the bolt. The lock may also include a cartridge
having a body portion and extension receiving portions. The extension receiving portions
may be able to receive the extensions of the locking mechanism. The lock may also
include a first coil positioned around the cartridge, a core disposed within the cartridge
and substantially within the first coil, and a first sliding barrier disposed within
the cartridge and comprising a first magnetic material. The first sliding barrier
may be selectively in communication with one or more of the extensions of the locking
mechanism. In addition, the first sliding barrier can be located on a first side of
the core and being magnetically attracted to the core. The lock may also include a
second sliding barrier disposed within the cartridge and having a second magnetic
material, where the second sliding barrier may be selectively in communication with
one or more of the extensions of the locking mechanism. The second sliding barrier
may be located on a second side of the core and may be magnetically attracted to the
core.
[0006] Moreover, the lock may also include a second coil positioned around the cartridge,
which may be spaced from the first coil and which may be positioned on the first side
of the core. The lock may also have a third coil positioned around the cartridge,
which may be spaced from the first coil and positioned on the second side of the core.
A control circuit of the lock may be in communication with the first, second, and
third coils. The control circuit may be able to energize the first coil to create
a magnetic field in the core, which magnetic field can cause the first and second
sliding barriers to move away from the core. The control circuit may also be able
to energize the second and third coils after a predetermined time has elapsed, such
that the first sliding barrier is magnetically attracted to the second coil and the
second sliding barrier is magnetically attracted to the third coil, thereby allowing
actuation of the locking mechanism.
[0007] Various embodiments of an electronic lock include a locking mechanism having a bolt
and one or more extensions coupled with the bolt and a cartridge having a body portion
and one or more extension receiving portions. The one or more extension receiving
portions may receive the one or more extensions of the locking mechanism. The lock
may also include a first coil positioned around the cartridge, a core disposed within
the cartridge and substantially within the first coil, and a second coil positioned
around the cartridge. The second coil may be spaced from the first coil. In addition,
a first sliding barrier may be disposed within the cartridge, which barrier may be
selectively in communication with the one or more extensions of the locking mechanism.
A control circuit may be included in the lock, which may energize the first and second
coils to cause the first sliding barrier to move from a first position magnetically
attracted to the core to a second position magnetically attracted to the second coil
and thereby allow actuation of the locking mechanism. In addition, in some embodiments,
the lock may be in combination with a key that has one or more shear pins that can
mate with one or more corresponding receptacles in the lock.
[0008] Moreover, a method of actuating an electronic lock includes, in certain embodiments,
energizing a first coil positioned around a cartridge of a lock assembly to generate
a first magnetic field within the cartridge and using the first magnetic field to
repel a barrier slidably disposed within the cartridge and in communication with a
locking mechanism, which repelling may cause the barrier to move from the first coil
toward a second coil positioned around the cartridge. The method may also include
energizing the second coil to generate a second magnetic field in the coil and using
the second magnetic field to attract the barrier to the second coil, such that the
barrier moves away from the locking mechanism and thereby allows movement of the locking
mechanism.
[0009] For purposes of summarizing the disclosure, certain aspects, advantages and novel
features of certain inventions have been described herein. It is to be understood
that not necessarily all such advantages may be achieved in accordance with any particular
embodiment of the inventions disclosed herein. Thus, the inventions disclosed herein
may be embodied or carried out in a manner that achieves or optimizes one advantage
or group of advantages as taught herein without necessarily achieving other advantages
as may be taught or suggested herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Throughout the drawings, reference numbers may be re-used to indicate correspondence
between referenced elements. The drawings are provided to illustrate embodiments of
the inventions described herein and not to limit the scope thereof.
FIGURE 1 is a side view of an embodiment of an electronic lock and key assembly.
FIGURE 2 is a perspective view of the electronic lock and key assembly of FIGURE1.
FIGURE 3 is a cross-sectional side view of the lock of FIG 1 in the locked position.
FIGURE 4 is a cross-sectional side view of the lock of FIGURE 1 in the unlocked position.
FIGURE 5 is a cross-sectional side view of the key of FIGURE 1.
FIGURE 6 is a perspective view of the key of FIGURE 1 sectioned along a vertical plane
extending through a longitudinal axis of the key.
FIGURE 7 is a perspective view of the key of FIGURE 1 sectioned along a vertical plane
extending through an intermediate portion of the key and generally normal to the longitudinal
axis.
FIG 8 is a cross-sectional side view of the lock and key assembly of FIGURE 1 in a
coupled position wherein a male probe of the key is inserted into a female receptacle
of the lock.
FIGURE 9 is a cross-sectional side view diagram of magnetic fields in accordance with
certain embodiments.
FIGURE 10 is an exemplary block diagram of circuit components in accordance with certain
embodiments.
FIGURES 11A and 11B illustrate an exemplary schematic diagram of circuit components
in accordance with certain embodiments.
FIGURE 12 depicts still another exemplary schematic diagram of circuit components
in accordance with certain embodiments.
FIGURES 13A and 13B illustrate an exemplary schematic diagram of circuit components
in accordance with certain embodiments.
FIGURE 14A illustrates a side perspective view of an embodiment of a coil assembly.
FIGURE 14B illustrates a front sectional view of an embodiment of the coil assembly
of FIGURE 14A.
FIGURE 14C illustrates a cross-sectional side view of an embodiment of the coil assembly
of FIGURE 14B.
FIGURES 15A through 15C illustrate cross-sectional side views of an embodiment of
a lock assembly containing the coil assembly of FIGURE 14.
FIGURES 16A through 16C illustrate embodiments of magnetic fields in the context of
the lock assembly of FIGURES 15A through 15C.
FIGURE 17 illustrates an embodiment of a control circuit for actuating the coil assembly
of FIGURES 14 through 16
FIGURE 18 illustrates an embodiment of a process for actuating the coil assembly of
FIGURES 14 through 16.
FIGURE 19A illustrates an isometric perspective view of an embodiment of a key having
shear pins.
FIGURE 19B illustrates an isometric perspective view of an embodiment of a lock having
shear pin receptacles.
FIGURE 20 illustrates a side cross-section view of an embodiment of the key of FIGURE
19A.
FIGURE 21 illustrates a side cross-section view of an embodiment of the lock of FIGURE
19B.
DETAILED DESCRIPTION
[0011] In the description below certain relative terms such as top, bottom, left, right,
front and back are used to describe the relationship between certain components or
features of the illustrated embodiments. Such relative terms are provided as a matter
of convenience in describing the illustrated embodiments and are not intended to limit
the scope of the technology discussed below.
1. Overview of the Key and Lock System
[0012] FIGURES 1 and 2 illustrate one embodiment of an electronic lock and key system, which
is generally referred to by the reference numeral 10. The electronic lock and key
system 10 includes a lock 100 and a key 200, which can engage one another and to selectively
move the key 200 between a locked position and an unlocked position. The lock and
key system 10 may be used to permit access to a location or enclosure in a variety
of applications, such as a cabinet or other such storage compartment, for example,
which may store valuable contents. Certain features, aspects and advantages of the
lock and key system 10 may be applied to other types of lock applications, such as
selectively permitting access to buildings or automobiles, for example, or for selectively
permitting operation of a device. Thus, although the present lock and key system 10
is disclosed herein in the context of a cabinet or storage compartment application,
the technology disclosed herein may be used with, or adapted for use with, other suitable
lock applications, as well.
[0013] The illustrated electronic lock and key system 10 can use electronic means to verify
the identity of the key and to actuate the internal mechanism of the lock 100. When
the key 200 engages the lock 100, data transfer and power transfer is enabled between
the lock 100 and the key 200. The lock 100 is then preferably permitted to be actuated
by the key 200 to move from a locked position to an unlocked position and permit access
to the space or location secured by the lock 100. In the illustrated arrangement,
the direction of power transfer preferably is from the key 200 to the lock 100, as
is described in greater detail below. However, in alternative arrangements, the direction
of power transfer may be reversed or may occur in both directions.
[0014] The illustrated lock 100 is preferably used in a cabinet, or other such storage compartment,
and can selectively secure a drawer or door of the cabinet relative to a body of the
cabinet. However, as will be appreciated, the lock 100 may be used in, or adapted
for use in, a variety of other applications. The lock 100 is preferably mounted to
the cabinet in such a way so as to allow only a front portion of the lock 100 to be
accessible when the cabinet is closed. The lock 100 includes an outer housing 102
with a cylinder 104 that is rotatable within the outer housing 102 when actuated by
the key 200. An exposed end of the cylinder 104 can support a lock tab (not shown).
The lock tab can cooperate with a stop. The lock 100 is associated with one of the
drawer (or door) of the cabinet and the cabinet body, and the stop is associated with
the other of the drawer (or door) of the cabinet and the cabinet body. The lock tab
rotates with the lock cylinder 104 to move between a locked position, wherein the
lock tab mechanically interferes with the stop, to an unlocked position, wherein the
lock tab does not interfere with the stop. In addition, other suitable locking arrangements
may be utilized.
II. Mechanical Aspects of the Key and Lock System
[0015] FIGURES 3 and 4 illustrate a cross-sectional view of the lock 100 of the electronic
lock and key assembly 10 of FIGURES 1 and 2. With additional reference to the FIGURES
3 and 4, the portion of the lock 100 on the left hand side of the FIGURES will be
referred to as the front of the lock and the portion on the right hand side of the
FIGURES will be referred to as the rear or back of the lock 100. As described above,
the lock 100 includes the housing 102 and the cylinder 104. The cylinder 104 can be
rotatable within the housing 102 by the key 200 when the lock 100 and the key 200
are properly engaged. The lock 100 further includes a cartridge 106, which includes
a mechanism that can selectively permit the cylinder 104 to rotate within the housing
102. The lock 100 further includes a mating portion 108 which can mate with the key
200 and an attack guard portion 110 which can protect the lock from unwanted tampering.
[0016] The housing 102 of the lock 100 preferably is a generally cylindrical tube with a
head portion 112 and a body portion 114. The diameter of the head portion 112 is larger
than the diameter of the body portion 114 such that the head portion 112 forms a flange
of the housing 102. The head portion 112 also includes an annular groove 174 or key
recess. Axially-extending slots 176 open into the annular groove 174 (FIGURE 2). The
groove 174 and slots 176 are used in engaging the key 200 with the lock 100 and are
described in greater detail below. The head portion 112 can house a seal member, such
as an O-ring 116, which is positioned to create a seal between the housing 102 and
the cylinder 104. Thus, the lock 100 is suitable for use in wet environments.
[0017] The lock housing 102 also includes a body portion 114 which extends rearwardly away
from the head portion 112. The rearward end of the body portion further includes a
threaded outer surface 115 which can receive a nut (not shown). The nut is used to
secure the lock 100 to a cabinet or other storage compartment. The body portion 114
also includes at least one, and preferably a pair of opposed flattened surfaces 113
or "flats" (FIGURE 2, only one shown), which are provided to reduce the likelihood
of rotation of the housing 102 in a storage container wall or door. Alternatively,
other mechanisms may be used to inhibit rotation of the housing 102 other than the
flattened surfaces 113.
[0018] With continued reference to FIGURES 3 and 4, the body portion 114 further includes
an internal groove 120 can secure the lock cylinder 104 from rotation relative to
the lock housing 112 when the lock 100 is in a locked position. The groove 120 preferably
is open towards an interior passage 121 of the body portion 114, which houses a portion
of the lock cylinder 104. The groove 120 extends axially along the body portion 114
and is formed partially through a thickness of the body portion 114 in a radial direction.
[0019] The body portion 114 further includes a tab 122 that extends slightly rearward from
the rearward end of the body portion 114. The tab 122 acts as a stop to limit the
rotation of a lock tab (not shown) secured to the cylinder 104.
[0020] The housing 102 can include a break-away feature incorporated into the structure
of the housing 102. The head portion 112 is formed with the body portion 114 in such
a way that if someone attempted to twist the housing 102 of the lock 100 by grasping
the head portion 112, the head portion 112 is capable of breaking free of the body
portion 114, preferably at a location near the intersection of the head portion 112
and the body portion 114 of the housing 102. This feature is advantageous in that
it increases the difficulty of opening or disabling the lock 100 by grasping the housing
102. That is, if a person were to attempt to grasp the head portion 112 and it were
to break away then there would no longer be an easily graspable surface with which
to try to rotate the lock 100 mechanically, without use of the key 200, because the
head portion 112, which is external to the cabinet, would no longer be coupled to
the body portion 114, which is internal to the cabinet. The break-away feature between
the head portion 112 and the body portion 114 may be created simply by a structure
that concentrates stresses at the head portion 112/body portion 114 junction. Alternatively,
the housing 102 may be deliberately weakened at or near the head portion 112/body
portion 114 junction, or at any other desirably or suitable location. Other anti-tampering
solutions may be employed as well.
[0021] With continued reference to FIGURES 3 and 4, as described above, the lock cylinder
104 includes a portion referred to as the cartridge 106. The cartridge 106 includes
a solenoid 126 with two adjacent slide bars 128. The slide bars 128 are spaced on
opposing sides of the solenoid 126 and can magnetically attract to the solenoid 126
when the lock 100 is in the locked position. The slide bars 128 preferably are constructed
with a neodymium-containing material, which may be encapsulated in a stainless steel
material for corrosion protection and wear resistance. When the lock 100 is moved
to an unlocked position, the solenoid 126 can reverse polarity such that the slide
bars 128 are magnetically repelled from the solenoid 126, as is described in greater
detail below. Preferably, the slide bars 128 are movable along an axis that is parallel
to (which includes coaxial with) a longitudinal axis of the lock 100.
[0022] The cartridge 106 is surrounded by a tamper-resistant case 124 that houses a circuit
board 134 can receive instructions when the key 200 engages with the lock 100. The
circuit board 134 is can recognize the proper protocol used to unlock the lock 100.
The circuit board 134 is further can actuate the solenoid 126 to reverse the polarity
of the solenoid 126 and repel the slide bars 128 away from the solenoid 126. The details
of the circuit board 134 and a method of communication between the key 200 and the
lock 100 are discussed in greater detail below. The interior of the case 124 preferably
is filled with a filler material, such as an epoxy, to occupy empty space within the
case 124 and protect and maintain a desired position of the components within the
case 124, such as the circuit board 134 and wires 160.
[0023] The lock cartridge 106 further includes two slide tubes 136 which are positioned
on opposite sides of the solenoid 126 and are can at least partially encapsulate the
slide bars 128 and are further can provide a smooth, sliding surface for the slide
bars 128. The slide tubes 136 each include an aperture 138 can receive at least a
portion of a bolt 130, or side bar, of the lock 100 when the lock 100 is in an unlocked
position.
[0024] The bolt 130 is preferably a relatively thin, generally block-shaped structure that
is movable between a locked position, in which rotation of the lock cylinder 104 relative
to the housing 102 is prohibited, and an unlocked position, in which rotation of the
lock cylinder 104 relative to the housing 102 is permitted. Preferably, the bolt 130
moves in a radial direction between the locked position and the unlocked position,
with the unlocked position being radially inward of the locked position.
[0025] The bolt 130 includes two cylindrical extensions 131, which extend radially inward
toward the cartridge 106. When the solenoid 126 is actuated to repel the slide bars
128 such that the apertures 138 are not blocked by the slide bars 128, the extensions
131 of the bolt 130 may enter into the case 124 through the apertures 138 as the bolt
130 moves radially inward.
[0026] The bolt 130 is preferably of sufficient strength to rotationally secure the cylinder
104 relative to the housing 102 when the bolt 130 is in the locked position, wherein
a portion of the bolt 130 is present within the groove 120. The bolt 130 has a sloped
or chamfered lower edge 129, which in the illustrated embodiment is substantially
V-shaped. The lower edge 129 can mate with the groove 120, which preferably is of
an at least substantially correspondingly shape to the lower edge 129 of the bolt
130. The V-shaped edge 129 of the bolt 130 interacting with the V-shaped groove 120
of the housing 102 urges the bolt 130 in a radially inward direction towards the cartridge
106 in response to rotation of the cylinder 104 relative to the housing 102. That
is, the sloped lower edge 129 and groove 120 cooperate to function as a wedge and
eliminate the need for a mechanism to positively retract the bolt 130 from the groove
120. Such an arrangement is used in certain embodiments due to its simplicity and
reduction in the number of necessary parts. However, other suitable arrangements to
lock and unlock the cylinder 104 relative to the housing 102 may also be used.
[0027] When the lock 100 is in an unlocked condition and the slide bars 128 are spaced from
the solenoid 126, as shown in FIGURE 4, the bolt 130 is free to move radially inward
(or upward in the orientation of FIGURE 4) into the cartridge 106, thus allowing the
cylinder 104 to rotate within the housing 102. Preferably, one or more biasing members,
such as springs, tend to urge the bolt 130 toward a locked position. In the illustrated
arrangement, two springs 132 are provided to produce such a biasing force on the bolt
130.
[0028] When the lock 100 is in a locked condition, the bolt 130 is extended radially outward
into engagement with the groove 120. The bolt 130 is prevented from inward movement
out of engagement with the groove 120 due to interference between the extensions 131
and the slide bars 128. When the lock 100 is in the unlocked position, the slide bars
128 are moved away from the solenoid 126 due to a switching of magnetic polarity of
the solenoid 126, which is actuated by the circuit board 134. The bolt 130 is then
free to move radially inward towards the center of the cylinder 104 and out of engagement
with the groove 120. At this point, the rotation of the cylinder 104 within the housing
102 may cause the bolt 130 to be displaced from engagement with the groove 120 due
to the cooperating sloped surfaces of the groove 120 and the lower edge 129 of the
bolt 130. The cylinder 104 is then free to be rotated throughout the unlocked rotational
range within the housing 102. When the cylinder 104 is rotated back to a locked position,
that is, when the lower edge 129 of the bolt 130 is aligned with the groove 120, the
bolt 130 is urged radially outward by the springs 132 such that the lower edge 129
is engaged with the groove 120. Once the extensions 131 of the bolt 130 are retracted
from the case 124 to a sufficient extent, the slide bars 128 are able to move towards
the solenoid 126 to once again establish the locked position of the lock 100.
[0029] Although
FIGURE 3 and
FIGURE 4 show a housing 102 with only one groove 120, multiple grooves 120 may be provided
within the housing 102 in other embodiments. Such a configuration may be advantageous
in that multiple bolts 130 may be provided, or if it is desirable to have multiple
locked positions using a single bolt 130 interacting with one of several available
grooves 120.
[0030] With continued reference to FIGURES 3 and 4, the lock 100 further includes an attack
guard portion 110 can inhibit access to the cartridge 106 such as by drilling, for
example, from the exposed portions of the lock, such as the head portion 112. The
illustrated attack guard portion 110 includes a radial array of pins 140 and an attack
ball 142, which are located along the longitudinal axis of the lock 100 between the
mating portion 108 and the cartridge 106. In the illustrated arrangement, the attack
ball 142 is generally centered relative to the longitudinal axis of the lock 100 and
is surrounded by the pins 140.
[0031] The pins 140 are preferably made from a carbide material, but can be made of any
suitable material or combination of materials that are capable of providing a suitable
hardness to reduce the likelihood of successful drilling past the pins 140 and attack
ball 142. The pins 140 are inserted into the cylinder 104 to a depth that is near
the outer extremity of the attack ball 142. A small space may be provided between
the outer end of the attack ball 142 and the end of the carbide pin 140 to allow for
the passage of the wires 160, which is discussed in greater detail below. The pins
140 are provided so as to add strength and hardness to the outer periphery of the
cylinder 104 adjacent to the attack ball 142.
[0032] The attack ball 142 is preferably made of a ceramic material but, similar to the
carbide pins, can be made of any suitable material that is of sufficient hardness
to reduce the likelihood of successful drilling of the lock cylinder 104. The attack
ball 142 is preferably generally spherical shape and lies within a pocket on substantially
the same axis as the cartridge 106. Preferably, the attack ball 142 is located in
front of the cartridge 106 and is aligned along the longitudinal axis of the lock
100 with the pins 140. The attack ball 142 can reduce the likelihood of a drill bit
passing through the cylinder and drilling out the cartridge 106. It is preferable
that if an attempt is made to drill out the cylinder 104, the attack ball 142 is sufficiently
hard as to not allow the drill bit to drill past the ball 142 and into the cartridge
106. The shape of the attack ball 142 is also advantageous in that it will likely
deflect a drill bit from drilling into the cartridge 104 by not allowing the tip of
the drill bit to locate centrally relative to the lock 100. Because the attack ball
142 is held within a pocket, it advantageously retains functionality even if cracked
or broken. Thus, the attack guard portion 110 can substantially reduce the likelihood
of success of an attempt to drill out the cartridge 106. In addition, or in the alternative,
other suitable arrangements to prevent drilling, or other destructive tampering, of
the lock 100 may be used as well.
[0033] One advantage of using the pins 140 and the attack ball 142 is that the entire lock
cylinder 104 does not have to be made of a hard material. Because the lock cylinder
104 includes many features that are formed in the material by shaping (e.g., casting
or forging) or material removal (e.g., machining), it would be very difficult to manufacture
a cylinder 104 entirely of a hard material such as ceramic or carbide. By using separate
pins 140 and an attack ball 142, which are made of a very hard material that is difficult
to drill, the lock cylinder 104 can be easily manufactured of a material such as stainless
steel which has properties that allow easier manufacture. Thus a lock cylinder can
be made that is both relatively easy to manufacture, but also includes drill resistant
properties.
[0034] With continued reference to FIGURES 3 and 4, the lock 100 includes a mating portion
108 located near the front portion of the lock 100. The mating portion 108 preferably
includes a mechanical mating portion 144 and a data and power mating portion 146.
The mechanical mating portion 144 includes a tapered cylindrical extension 148 that
extends in a forward direction from the lock cylinder 104 and can be received within
a portion of the key 200 when the lock 100 and the key 200 are engaged together. At
the base of the extension 148 are two recesses 150 that can mate with two extensions,
or protrusions, on the key 200, which are described in greater detail below. The recesses
150 can allow the key 200 to positively engage the cylinder 104 such that torque can
be transferred from the key 200 to the cylinder 104 upon rotation of the key 200.
[0035] The data and power mating portion 146 includes a mating cup 152, a data coil 154,
and a power coil 156. The cup 152 can receive a portion of key 200 when the lock 100
and the key 200 are engaged together. The cup 152 resides at least partially in an
axial recess 158 which is located in a front portion of the lock cylinder 104 and
further houses the attack ball 142. The cup is at least partially surrounded by the
power coil 156, which can inductively receive power from the key 200. The cup 152
preferably includes axial slots 161 that can allow power to transmit through the cup
152.
[0036] The data coil 154 is located towards the upper edge of the cup 152 and, preferably,
lies just rearward of the forward lip of the cup 152. The data coil 154 is generally
of a torus shape and can cooperate with a data coil of the key 200, as is described
in greater detail below. Two wires 160 extend from the cup 152, through a passage
162, and into the lock cartridge 106. The wires 160 preferably transmit data and power
from the data and power mating portion 146 to the solenoid 126 and the circuit board
134.
[0037] The power coil 156 is preferably aligned with a longitudinal axis of the lock 100
so that a longitudinal axis passing through the power coil 156 is substantially parallel
(or coaxial) with a longitudinal axis of the lock 100. The data coil 154 is preferably
arranged to generally lie in a plane that is orthogonal to a longitudinal axis of
the lock. Such an arrangement helps to reduce magnetic interference between the transmission
of power between the lock 100 and the key 200 and the transmission of data between
the lock 100 and the key 200.
[0038] As described above, the lock cylinder 104 can support a lock tab, which interacts
with a stop to inhibit opening of a cabinet drawer or door, or prevent relative movement
of other structures that are secured by the lock and key system 10. The lock cylinder
104 includes a lock tab portion 164 that can support a lock tab in a rotationally
fixed manner relative to the lock cylinder 104. The lock tab portion 164 includes
a flatted portion 166 and a threaded portion 168. The flatted portion 166 can receive
a lock tab (not shown) which can slide over lock tab portion 164 and mate with the
flatted portion 166. One or more flat surfaces, or "flats," on the flatted portion
166 can allow the transmission of torque from the cylinder 104 to the lock tab (not
shown). The threaded portion 168 can receive a nut (not shown), which can secure the
lock tab (not shown) to the cylinder 104.
[0039] FIGURES 5-7 illustrate an embodiment of the key 200 that may be used with the lock 100 of the
electronic lock and key assembly 10. The key 200 can mate with the lock 100 to permit
power and data communication between the key 200 and the lock 100. In the illustrated
arrangement, the key 200 can also mechanically engage the lock 100 to move the lock
from a locked to an unlocked position or vise versa.
[0040] The key 200 includes an elongate main body section 204 that is generally rectangular
in cross-sectional shape. The key 200 also includes a nose section 202 of smaller
external dimensions than the body section 204. An end section 206 closes and end portion
of the body section 204 opposite the nose section 202. The nose section 202 can engage
the lock 100 and the body section 204 can house the internal electronics of the key
200 as well as other desirable components. The end section 206 is removable from the
body section 204 to permit access to the interior of the body section 204.
[0041] With continued reference to FIGURES 5-7, the nose section 202 includes a tapered
transition portion 208 which extends between a cylindrical portion 210 of the nose
section 202 and the body section 204. The cylindrical portion 210 houses the power
and data transfer portion 212 of the key 200, which is discussed in greater detail
below.
[0042] On the outer surface of the cylindrical portion are two radiused tabs 214 which can
rotationally locate the key 200 relative to the lock 100 prior to the key 200 engaging
the lock 100. The tabs 214 extend radially outward from the outer surface of the cylindrical
portion 210 and, preferably, oppose one another.
[0043] The cylindrical portion 210 further includes two generally rectangular extensions
216 that extend axially outward and can engage with the recesses 150 of the lock 100
(FIGURE 3) when the key 200 engages the lock 100. The rectangular extensions 216 can
couple the nose section 202 of the key 200 to the lock cylinder 104 and to transmit
torque from the key 200 to the cylinder 104 when the key 200 is rotated.
[0044] The cylindrical portion 210 includes a recess 218 that opens to the front of the
key 200. Located within the recess 218 is the power and data transfer portion 212
of the key 200. Preferably, the power and data transfer portion 212 is generally centrally
located within the recess 218 and aligned with the longitudinal axis of the key 200.
The power and data transfer portion 212 includes a power coil 220 and a data coil
222. The power coil 220 is generally cylindrical in shape with a slight taper along
its axis. The power coil 220 is positioned forward of the data coil 222 and, preferably,
remains within the recess 218 of the cylindrical portion 210. The power coil 220 can
be inductively coupled with the power coil 152 of the lock 100. The data coil 222
is generally toroidal in shape and is located at the base of the recess 218. The data
coil 222 can be inductively coupled with the data coil 154 of the lock 100, as is
described in greater detail below.
[0045] With continued reference to FIGURES 5-7, in the illustrated arrangement, the nose
section 202 is a separate component from the body section 204 and is connected to
a forward end of the body section 204 of the key 200. The nose section 202 mates with
the body section 204 and is sealed by a suitable seal member, such as O-ring 224,
which inhibits contaminants from entering the interior of the key 200. The nose section
202 is secured to the body section by two fastening members, such as screws 226 (FIGURES
1 and 5). Similarly, the end section 206 is a separate component from the body section
204 and is coupled to a rearward end of the body section 200. The end section is substantially
sealed to the body section 204 by a suitable seal member, such as O-ring 230, which
can inhibit contaminants from entering the interior of the key 200. Thus, the key
200 preferably is suitable for use in wet environments. The end section 206 is secured
to the body section 204 by a fastening member, such as screw 232, which can retain
the end section 206 to the body section 204.
[0046] The body section 204 includes three externally-accessible input buttons 228 extending
from the body section 204 (upward in the orientation of FIGURE 5). The input buttons
228 are in electrical contact with a processing unit 229 of the key 200, which preferably
includes a processor and a memory. The input buttons 228 permit data to be entered
into the key 200, such as a wake-up or programming code, for example. Certain functional
features of the key 200 are described in greater detail below with reference to FIGURES
9-12.
[0047] With reference to
FIGURES 6 and
7, the key 200 further includes a plurality of axially-extending cavities 236. The illustrated
key 200 includes four cavities 236. The axial cavities 236 extend through at least
a significant portion of the length of the body section 204 and are preferably circular
in cross-sectional shape. The axial cavities 236 can house battery cells (not shown)
that provide a source of power within the key 200, which provides power to the lock
100 when the key 200 and the lock 100 are engaged. The cavities 236 are preferably
arranged in a side-by-side manner and surround a longitudinal axis of the key 200.
The key 200 preferably includes a power source (discussed below) and can be rechargeable.
Preferably, the key 200 includes a recharge port (not shown), which can mate with
an associated recharge port of a recharger (not shown) when it is desired to recharge
the key 200.
[0048] With reference to
FIGURES 2 and
8, the key 200 is shown about to engage the lock 100, and engaging the lock 100, respectively.
When the key 200 engages with the lock 100, desirably, certain mechanical operations
occur and certain electrical operations occur. When engaging the key 200 with the
lock 100, the key 200 is rotationally positioned relative to the lock 100 such that
the tabs 214 of the key 200 are aligned with the slots 176 (FIGURE 2) of the lock
100. The key 200 is then displaced axially such that the tabs 214 pass through the
slots 176 and the cylindrical portion 210 of the key 200 is positioned within the
housing 102 of the lock 100. The key 200 is sized and shaped such that the tabs 214
are located within the annular groove 174, which has a shape that closely matches
the profile of the tabs 214. In this relative position, the key 200 is able to rotate
within the housing 100, so long as the key 200 is a proper match for the lock 100
and the lock is moved to the unlocked position, as is described in greater detail
below.
[0049] Furthermore, when the key 200 engages the lock 100, the cylindrical extension 148
of the lock 100 is received within the recess 218 of the key. The recess 218 is defined
by a tapered surface which closely matches a tapered outer surface of the cylindrical
extension 148. The cooperating tapered surfaces facilitate smooth engagement of the
lock 100 and key 200, while also ensuring proper alignment between the lock 100 and
key 200. Furthermore, the rectangular extensions 216 of the key 200 insert into the
recesses 150 of the lock 100 to positively engage the key 200 with the lock 100 so
that rotation of the key 200 results in rotation of the lock cylinder 104 within the
housing 102.
[0050] When the key 200 engages the lock 100, the power coil 220 of the key 200 is aligned
for inductive coupling with the power coil 156 of the lock 100. Also, the data coil
222 of the key 200 is aligned for inductive coupling with the data coil 154 of the
lock 100. Preferably, the power coil 220 of the key 200 is inserted into the cup portion
152 of the lock 100 and thus the power coil 156 of the lock 100 and the power coil
220 of the key 200 at least partially overlap along the longitudinal axis of the lock
100 and/or key 200. Furthermore, preferably, the data coil 154 of the lock 100 and
the data coil 222 of the key 200 come into sufficient alignment for inductive coupling
when the key 200 engages the lock 100. That is, in the illustrated arrangement, when
the key 200 engages the lock 100, the data coil 222 of the key 200 and the data coil
154 of the lock 100 are positioned adjacent one another and, desirably, are substantially
coaxial with one another. Furthermore, a plane which passes through the data coil
222 of the key 200 preferably is substantially parallel to a plane which passes through
the data coil 154 of the lock 100. Desirably, the spacing between the data coils 154
and 222 is within a range of about 30-40 mils (or 0.03-0.04 inches). Such an arrangement
is beneficial to reduce interference between the power transfer and the data transfer
between the lock 100 and key 200, as is described in greater detail below. However,
in other arrangements, a greater or lesser amount of spacing may be desirable.
[0051] In the illustrated embodiment of the lock and key system 10, when the key 200 engages
the lock 100 there are two transfers that occur. The first transfer is a transfer
of data and the second transfer is a transfer of power. During engagement of the key
200 and the lock 100, the data coils 222 and 154, in the illustrated embodiments,
do not come into physical contact with one another. Similarly, the power coil 200
of the key 200 and power coil 156 of the lock 100, in the illustrated embodiment,
do not come into physical contact with one another. The data is preferably transferred
between the data coil 222 of the key 200 and the data coil 154 of the lock 100 by
induction, as described in connection with FIGURE 9 below. The power is also transferred
between the power coil 200 of the key 200 and the power coil 156 of the lock 100 preferably
once again by induction, as is also described in connection with FIGURE 9 below. When
engagement between the key 200 and the lock 100 has been made, a data protocol occurs
which signals to the circuit board 134 that the proper key 200 has been inserted into
the lock 100. Power is transferred from the key 200 to the lock 100 to activate the
solenoid 126, which permits the lock 100 to be unlocked by rotation of the key 200.
III. Electrical Aspects of the Key and Lock System
[0052] FIGURE 9 depicts an embodiment of a magnetic field diagram 400. In the magnetic field diagram
400, a cross-section view of a power coil 402, interior power coil 418, first data
coil 406, and second data coil 408 are depicted in relation to a power magnetic field
404 and a data magnetic field 410 generated by the coils 406 and 408. In the depicted
embodiment, the configuration of the power coil 402, interior power coil 418, first
data coil 406, and second data coil 408 causes the power magnetic field 404 to be
orthogonal or substantially orthogonal to the data magnetic field 410 at certain locations.
This orthogonal relationship facilitates data transfer between the data coils 406,
408 with little or no interference from the power magnetic field 404. The coils 402,
406, 408 and 418, as illustrated, correspond with the power and data coils of the
lock 100 and key 200 of FIGURES 1-8. In particular, the power coil 402 corresponds
with the lock power coil 156, the interior power coil 418 corresponds with the key
power coil 220, the data coil 406 corresponds with the lock data coil 154 and the
data coil 408 corresponds with the key data coil 222. However, the physical relationships
between the coils may be altered in alternative embodiments from the locations shown
in FIGURES 1-8; however, preferably the interference reduction or elimination concepts
disclosed herein are still employed.
[0053] The power coil 402 of certain embodiments is a solenoid. The solenoid includes windings
420 which are loops of wire that are wound tightly into a cylindrical shape. In the
depicted embodiment, the power coil 402 includes two sets of windings 420. Two sets
of windings 420 in the power coil 402 reduce air gaps between the wires and thereby
increase the strength of a magnetic field generated by the power coil 402.
[0054] The depicted embodiment of the power coil 402 does not include a magnetic core material,
such as an iron core, although in certain embodiments, a magnetic core material may
be included in the power coil 402. In other embodiments, while the power coil 402
is depicted as a solenoid, other forms of coils other than solenoids may be used.
[0055] The power coil 402 may form a portion of a lock assembly, though not shown, such
as any of the lock assemblies described above. Alternatively, the power coil 402 may
be connected to a key assembly, such as any of the key assemblies described above.
In addition, the power coil 402 may be connected to a docking station (not shown),
as described in connection with FIGURE 10, below.
[0056] The power coil 402 is shown having a width 414 (also denoted as "Wp"). The width
414 of the power coil 402 is slightly flared for the entire length of the power coil
402. The overall shape of the power coil 402, including its width 414, determines
in part the shape of the magnetic field emanating from the power coil 402. In certain
embodiments, a constant or approximately constant width 414 of the power coil 402
does not change the shape of the power magnetic field 404 substantially from the shape
illustrated in FIGURE 9.
[0057] The power coil 402 further includes a casing 462 surrounding the power coil 402.
In one embodiment, the casing 462 is a non-conducting material (dielectric). The casing
462 of certain embodiments facilitates the power coil 402 receiving the interior power
coil 418 inside the power coil 402. The casing 462 prevents electrical contact between
the power coil 402 and the interior power coil 418. Thus, in the embodiment described
with reference to FIGURES 1-8, the cup 152 of the lock 100 may be constructed from,
or include, an insulation material. Furthermore, other physical structures interposed
between adjacent coils may be made from, or include, insulating materials.
[0058] In alternative embodiments, the casing 462 is made of a metal, such as steel. The
strength of a metal casing 462 such as steel helps prevent tampering with the power
coil 402. However, magnetic fields often cannot penetrate more than a few layers of
steel and other metals. Therefore, the metal casing 462 of certain embodiments includes
one or more slits or other openings (not shown) to allow magnetic fields to pass between
the power coil 402 and the interior power coil 418.
[0059] The interior power coil 418 mates with the power coil 402 by fitting inside the power
coil 402. In certain embodiments, the interior power coil 418 has similar characteristics
to the power coil 402. For instance, the interior power coil 418 in the depicted embodiment
is a solenoid with two windings 420. In addition, the interior power coil 418 may
receive a current and thereby generate a magnetic field. The interior power coil 418
is also covered in a casing material 454, which may be an insulator or metal conductor,
to facilitate mating with the power coil 402. Furthermore, the interior power coil
418 also has a width 430 (also denoted "W
i") that is less than the width 414 of the power coil 402, thereby allowing the interior
power coil 418 to mate with the power coil 402.
[0060] In addition to these features, the interior power coil 418 of certain embodiments
includes a ferromagnetic core 452, which may be a steel, iron, or other metallic core.
The ferromagnetic core 452 increases the strength of the power magnetic field 404,
enabling a more efficient power transfer between the interior power coil 418 and the
power coil 402. In addition, the ferromagnetic core 452 in certain embodiments enables
the frequency of the power signal to be reduced, allowing a processor in communication
with the power coil 418 to operate at a lower frequency and thereby decrease the cost
of the processor.
[0061] The interior power coil 418 may form a portion of a lock assembly, though not shown,
such as any of the lock assemblies described above. Alternatively, the interior power
coil 418 may be connected to a key assembly, such as any of the key assemblies described
above. In addition, the interior power coil 418 may be connected to a docking station
(not shown), as described in connection with FIGURE 10, below.
[0062] A changing current flow through the interior power coil 418 induces a changing magnetic
field. This magnetic field, by changing with respect to time, induces a changing current
flow through the power coil 402. The changing current flow through the power coil
402 further induces a magnetic field. These two magnetic fields combine to form the
power magnetic field 404. In such a state, the power coil 402 and the interior power
coil 418 are "inductively coupled," which means that a transfer of energy from one
coil to the other occurs through a shared magnetic field, e.g., the power magnetic
field 402. Inductive coupling may also occur by sending a changing current flow through
the power coil 402, which induces a magnetic field that in turn induces current flow
through the interior power coil 418. Consequently, inductive coupling may be initiated
by either power coil.
[0063] Inductive coupling allows the interior power coil 418 to transfer power to the power
coil 402 (and vice versa). An alternating current (AC) signal flowing through the
interior power coil 418 is communicated to the power coil 402 through the power magnetic
field 404. The power magnetic field 404 generates an identical or substantially identical
AC signal in the power coil 402. Consequently, power is transferred between the interior
power coil 418 and the power coil 402, even though the coils are not in electrical
contact with one another.
[0064] In certain embodiments, the interior power coil 418 has fewer windings than the power
coil 402. A voltage signal in the interior power coil 418 is therefore amplified in
the power coil 402, according to known physical relationships in the art. Likewise,
a voltage signal in the power coil 402 is reduced or attenuated in the interior power
coil 418. In addition, the power coil 402 may have fewer windings than the interior
power coil 418, such that a voltage signal from the interior power coil 418 to the
power coil 402 is attenuated, and a voltage signal from the power coil 402 to the
interior power coil 418 is amplified.
[0065] The power magnetic field 404 is shown in the depicted embodiment as field lines 434;
however, the depiction of the power magnetic field 404 with field lines 434 is a model
or representation of actual magnetic fields, which in some embodiments are changing
with respect to time. Therefore, the power magnetic field 404 in certain embodiments
is depicted at a moment in time. Moreover, the depicted model of the power magnetic
field 404 includes a small number of field lines 434 for clarity, but in general the
power magnetic field 404 fills all or substantially all of the space depicted in FIGURE
9.
[0066] Portions of the field lines 434 of the power magnetic field 404 on the outside of
the power coil 402 are parallel or substantially parallel to the axis of the power
coil 402. The parallel nature of these field lines 434 in certain embodiments facilitates
minimizing interference between power and data transfer, as is described below.
[0067] The first data coil 406 is connected to the power coil 402 by the casing 462. The
first data coil 406 has one or more windings 422. In one embodiment, the first data
coil 406 is a toroid including tightly-wound windings 422 around a ferromagnetic core
472, such as steel or iron. The ferromagnetic core 472 of certain embodiments increases
the strength of a magnetic field generated by the first data coil 406, thereby allowing
more efficient transfer of data through the data magnetic field 410. In addition,
the ferromagnetic core 472 in certain embodiments enables the frequency of the data
signal to be reduced, allowing a processor in communication with the first data coil
406 to operate at a lower frequency and thereby decreasing the cost of the processor.
[0068] Though not shown, the first data coil 406 may further include an insulation material
surrounding the first data coil 406. Such insulation material may be a non-conducting
material (dielectric). In addition, the casing 462 covering the power coil 402 in
certain embodiments also at least partially covers the first data coil 406, as shown.
The casing 462 at the boundary between the first data coil 406 and the second data
coil 408 may also include a slit or other opening to allow magnetic fields to pass
between the first and second data coils 406, 408.
[0069] The first data coil 406 has a width 416 (also denoted as "W
d"). This width 416 is greater than the width 414 of the power coil 402 in some implementations.
In alternative embodiments, the width 416 may be equal to or less than the width 414
of the power coil 402.
[0070] The second data coil 408 in the depicted embodiment is substantially identical to
the first data coil 406. In particular, the second data coil 408 is a toroid including
tightly-wound windings 424 around a ferromagnetic core 474, such as steel or iron.
The ferromagnetic core 474 of certain embodiments increases the strength of a magnetic
field generated by the second data coil 408, thereby allowing more efficient transfer
of data through the data magnetic field 410, allowing a processor in communication
with the second data coil 408 to operate at a lower frequency and thereby decreasing
the cost of the processor.
[0071] The second data coil 408 in the depicted embodiment has a width 416 equal to the
width 414 of the first data coil 406. In addition, the second data coil 408 may have
an insulating layer (not shown) and may be covered by the casing 454, as shown. However,
in certain embodiments, the second data coil 408 has different characteristics from
the first data coil 406, such as a different number of windings 424 or a different
width 416. In addition, first and second data coils 406, 408 having different widths
may overlap in various ways.
[0072] When a current is transmitted through either the first data coil 406 or the second
data coil 408, the first data coil 406 and the second data coil 408 are inductively
coupled, in a similar manner to the inductive coupling of the power coil 402 and the
interior power coil 418. Data in the form of voltage or current signals may therefore
be communicated between the first data coil 406 and the second data coil 408. In certain
embodiments, data may be communicated in both directions. That is, either the first
or second data coil 406, 408 may initiate communications. In addition, during one
communication session, the first and second data coils 406, 408 may alternate transmitting
data and receiving data.
[0073] Data magnetic field 410 is depicted as including field lines 442, a portion of which
are orthogonal or substantially orthogonal to the data coils 406, 408 along their
width 416. Like the field lines 434, 436 of the power magnetic field 404, the field
lines 442 of the data magnetic field 410 are a model of actual magnetic fields that
may be changing in time. The orthogonal nature of these field lines 442 in certain
embodiments facilitates minimizing the interference between power and data transfer.
[0074] In various embodiments, at least a portion of the data magnetic field 410 is orthogonal
to or substantially orthogonal to the power magnetic field 404 at certain areas of
orthogonality. These areas of orthogonality include portions of an interface 412 between
the first data coil 406 and the second data coil 408. This interface 412 in certain
embodiments is an annular or circumferential region between the first data coil 406
and second data coil 408. At this interface, at least a portion of the data magnetic
field 410 is substantially parallel to the first data coil 406 and second data coil
408. Because the data magnetic field 410 is substantially parallel to the data coils
406, 408, the data magnetic field 410 is therefore substantially orthogonal to the
power magnetic field 404 at portions of the interface 412.
[0075] According to known relationships in the physics of magnetic fields, magnetic fields
which are orthogonal to each other have very little effect on each other. Thus, the
power magnetic field 404 at the interface 412 has very little effect on the data magnetic
field 410. Consequently, the data coils 406 and 408 can communicate with each other
with minimal interference from the potentially strong power magnetic field 404. In
addition, data transmitted between the data coils 406, 408 does not interfere or minimally
interferes with the power magnetic field 404. Thus, data may be sent across the data
coils 406, 408 simultaneously while power is being sent between the power coil 402
and the interior power coil 418.
[0076] FIGURE 10 depicts embodiments of a key circuit 510 and a lock circuit 530. In the
depicted embodiment, the key circuit 510 is shown in proximity to the lock circuit
530. The relative locations of the key circuit 510 and the lock circuit 530 shows
that in certain implementations components of the key circuit 510 interface with components
of the lock circuit 530. Moreover, the key circuit 510 may in certain embodiments
be contained in a key assembly such as any of the keys described above. Likewise,
the lock circuit 530 may be contained in a lock assembly such as any of the locks
described above.
[0077] The key circuit 510 includes a processor 502. The processor 502 may be a microprocessor,
a central processing unit (CPU), a microcontroller, or other type of processor. The
processor 502 in certain embodiments implements program code. By implementing program
code, the processor 502 sends certain signals to the lock circuit 530 and receives
signals from the lock circuit 530. Such signals may include power signals, data signals,
and the like.
[0078] A memory device 526 is in communication with the processor 502. The memory device
526 in certain embodiments is a flash memory, hard disk storage, an EEPROM, or other
form of storage. The memory device 526 in certain embodiments stores program code
to be run on the processor 502. In addition, the memory device 526 may store data
received from the processor 502.
[0079] Data stored on the memory device 526 may include encryption data. In one embodiment,
the encryption data includes one or more encryption keys that when communicated to
the lock circuit 530 effectuate unlocking a lock. Several different encryption schemes
may be used in various embodiments.
[0080] Data stored by the memory device 526 may also include audit data. Audit data in some
implementations is data received from the lock circuit 530 or generated by the key
circuit 510 that identifies past transactions that have occurred between the lock
and other keys. For instance, audit data may include ID numbers of keys used to access
the lock, including keys which unsuccessfully used the lock. This data allows security
personnel to monitor which individuals have attempted to access the lock. The audit
data may further include several other types of information.
[0081] A data coil 512 is in communication with the processor 502 through conductors 504
and 506. The data coil 512 may be any of the data coils described above. The data
coil 512 in certain embodiments receives data from the processor 502. This data may
be in the form of a voltage or current signal which changes with respect to time,
such that certain changes in the signal represent different symbols or encoded information.
Because the signal changes with respect to time, a magnetic field is generated in
the data coil 512 which induces a magnetic field in a corresponding data coil 532
in the lock circuit 530. The magnetic field in the data coil 532 further induces a
voltage or current signal, which contains the same information or substantially the
same information as the voltage or current signal generated in the data coil 512.
Thus, the data coil 512 facilitates communication between the key circuit 510 and
the lock circuit 530.
[0082] In certain embodiments, the data coil 512 receives data in a like manner from the
data coil 532 of the lock circuit 530. A voltage or current signal induced in the
data coil 512 is sent to the processor 502, which processes the information conveyed
in the voltage or current signal. The data coil 512 may also send and receive information
to and from a docking station (not shown), which is described more fully below.
[0083] One or more switches 516 are in communication with the data coil 512 and with the
processor 502. The switches 516 in certain embodiments are transistor switches, relays,
or other forms of electronic switches which selectively direct current flow to different
parts of the key circuit 510. In the depicted embodiment, switches 516 direct current
flow between the data coil 512 and the processor 502. The switches 516 therefore selectively
allow the processor 502 to both send and receive data.
[0084] A power coil 514 is in communication with the processor 502 via conductors 508 and
510. The power coil 514 in certain embodiments transmits power to the key circuit
530. In certain implementations, the power coil 514 may be any of the power coils
described above. In one implementation, the power coil 514 receives an alternating
current (AC) signal. This AC signal induces a magnetic field in a corresponding power
coil 534 in the lock circuit 530. In one embodiment, the AC signal oscillates at an
appropriate frequency to effectuate optimal power transfer between the key circuit
510 and the lock circuit 530. For example, the oscillation may occur at 200 kilohertz.
Alternatively, the oscillation may occur at a different frequency which may be chosen
so as to minimize interference with other circuit components.
[0085] One or more switches 518 are in communication with the power coil 514 and a processor
502. Like the switches 516, the switches 518 may be transistor switches, relays or
any other form of electronic switch. The switches 518 in certain embodiments allow
power to be transmitted to the power coil 514 from the processor 502. In such embodiments,
the switches 518 are closed, allowing current to transfer from the processor 502 to
the power coil 514. The switches 518 may be opened when the power coil 514 is receiving
power such as from a docking station. When the switches 518 are open, power received
from the power coil 514 in certain embodiments cannot be transmitted to the processor
502. The switches 518 therefore protect the processor 502 from receiving harmful current
signals while simultaneously allowing the processor 502 to transmit power to the power
coil 514.
[0086] A rectifier circuit 520 is in communication with the power coil 514 via conductors
508 and 510. The rectifier circuit 520 in certain embodiments includes one or more
diodes. The diodes may form a bridge rectifier or other form of rectifier. The diodes
of the rectifier circuit 520 rectify an incoming signal from the power coil 514. Rectification
in certain embodiments includes transforming an alternating current signal into a
direct current signal by converting the AC signal into one of constant polarity. Rectification
may further include smoothing the signal, for example, by using one or more capacitors,
and thereby creating a direct current signal that can power circuit components.
[0087] A recharge circuit 522 is in communication with the rectifier 520. The recharge circuit
522 in certain embodiments recharges a battery 524 when the key circuit 510 is in
communication with a docking station (not shown). The battery 524 may be a lithium
iron battery, a nickel cadmium battery or other form of rechargeable battery. The
battery may also be an alkaline or other non-rechargeable battery. In addition, the
battery 524 may include multiple batteries. In one embodiment, the battery 524 receives
power from the recharge circuit 522 in order to recharge the battery. In addition,
the battery 524 sends power to the processor 502, to the memory device 526, and to
other components in the key circuit 530.
[0088] In some implementations, the key circuit 510 is capable of communicating with a docking
station (not shown) connected to an AC power supply, such as a wall outlet. The docking
station in one embodiment has a power coil and a data coil, similar to a power coil
534 and data coil 532 of the lock circuit 530 described below. The docking station
receives the data coil 512 and the power coil 514 such that the key circuit 510 can
communicate with the docking station. In one embodiment, the power coil 514 receives
power from the docking station and transfers this power to the rectifier 520 and recharge
circuit 522, effectuating recharge of the battery 524.
[0089] In addition, the data coil 512 may receive data from a corresponding data coil in
the docking station. Such information might include, for example, program code to
be stored on the memory device 526, program code to be run on the processor 502, data
to be stored in the memory device 526 including encryption data, data regarding locking
codes and the like, as well as ID data, tracking data, and the like. In addition,
the docking station may transmit data, codes, or the like to the key circuit 510 which
enable the key to be used for a limited time, such as a couple of hours or days. The
data coil 512 may also transmit data to the docking station via a corresponding data
coil. Such data might also include audit information, tracking information, and the
like.
[0090] The docking station may also be connected to a computer. Programs can be run on the
computer which facilitate the docking station communicating with the key circuit 510.
Consequently, the key circuit 510 may be recharged and reprogrammed by the docking
station of certain embodiments.
[0091] Turning to the lock circuit 530, the lock circuit 530 includes a processor 546. Like
the processor 502 of the key circuit 510, the processor 546 may be a microprocessor,
a central processing unit (CPU), or any other type of processor. The processor 546
in certain embodiments implements program code. By implementing program code, the
processor 546 may send certain signals to the key circuit 510 and receive signals
from the key circuit 510. Such signals may include power signals, data signals, and
the like.
[0092] A memory device 548 is in communication with the processor 546. The memory device
548 in certain embodiments is a flash memory, hard disk storage, an EEPROM, or other
form of storage. The memory device 548 in certain embodiments stores program code
to be run on the processor 546. In addition, the memory device 548 may store data
received from the processor 546.
[0093] Data stored on the memory device 548 may include encryption data. In one embodiment,
the encryption data includes one or more encryption keys. When an identical encryption
key is received from a key circuit 510 in certain embodiments, the lock circuit 530
unlocks a lock. The memory device 548 may also include audit data. This data allows
security personnel to monitor which individuals have attempted to access the lock.
[0094] A data coil 532 is in communication with the processor 546 through conductors 536
and 538. The data coil 532 may be any of the data coils described above. The data
coil 532 in certain embodiments receives data from the processor 546 and transmits
the data to the key circuit 510. In other embodiments, the data coil 532 receives
data from the key circuit 510 via magnetic fields generated by the data coil 512.
[0095] One or more switches 544 are in communication with the data coil 532 and with the
processor 546. The switches 544 in certain embodiments are transistor switches, relays,
or other forms of electronic switches which selectively direct current flow to different
parts of the key circuit 530. In the depicted embodiment, switches 544 may be used
to direct current flow between the data coil 532 and the processor 546. Like the switches
516 in the key circuit 510, the switches 544 selectively allow the processor 502 to
both send and receive data.
[0096] A power converter 550 is in communication with the processor 546 and with the power
coil 534. The power converter 550 in one embodiment includes a rectifier circuit such
as the rectifier circuit 528 described above. The power converter 550 may further
include a low drop-out regulator (described in connection with FIGURE 11, below).
In addition, the power converter may include other circuit components common to power
regulation.
[0097] In one embodiment, the power converter 550 receives an oscillating power signal from
the power coil 534. The power converter 550 includes a rectifier circuit, similar
to the rectifier circuit 520 described above, which converts the oscillating signal
into two components, namely an AC component signal and a direct current (DC) component
signal. In one embodiment, the AC component signal is provided to a solenoid 552 through
conductor 574, and the DC component signal is provided to the processor 546 through
conductor 572. Consequently, the power converter 550 enables the lock circuit 530
to run on both AC and DC power.
[0098] The solenoid 552 receives the AC component signal from the power converter 550. The
solenoid 552 in one embodiment is a coil containing one or more windings. The solenoid
552, upon receiving current from the power converter 550, generates a magnetic field
to actuate an unlocking mechanism in a lock, in a manner similar to that which is
described above.
[0099] A switch 554 is in communication with the solenoid 552 through a conductor 576. The
switch 554 is also in communication with the processor 546 through a conductor 580.
In addition, the switch 554 is in communication with ground 578. The switch 554 enables
or disables the solenoid 552 from receiving current, thereby causing the solenoid
552 to lock or unlock. In one embodiment, the processor 546 sends a signal through
the conductor 580 to the switch 554 that closes the switch 554 and thereby creates
a conduction path from the solenoid 552 to ground 578. With the switch closed 554,
the solenoid 552 is able to receive current from the power converter 550 and thereby
effectuate unlocking. At other times, the processor 546 will not send a signal 580
to the switch 554 and thereby cause the switch to be open, preventing current from
flowing through the solenoid 552 and thereby locking the lock. Alternatively, the
processor 546 can send a signal over the signal line 580 to the switch 554 which will
cause the switch to remain open.
[0100] While not shown, in certain embodiments the lock circuit 530 includes a battery in
addition to, or in place of, the battery 524 in the key circuit 500. In such instances,
the lock circuit 530 may provide power to the key circuit 510. This power may recharge
the battery 524. Alternatively, if the key circuit 510 does not have a battery 524,
power transmitted from the battery in the lock circuit 530 may power the key circuit
510.
[0101] FIGURES 11A and
11B depict one specific implementation of a key circuit, referred to by the reference
numeral 600, which is substantially similar in structure and function to the key circuit
510 described above. FIGURES 11A and 11B depict separate portions of the key circuit
600, but these separate portions together constitute one key circuit 600. Certain
components of the key circuit 600 are therefore duplicated on each FIGURE to more
clearly show the relationship between the portion of the key circuit 600 depicted
in FIGURE 11A with the portion of the key circuit 600 depicted in FIGURE 11B. Although
the implementation shown in FIGURES 11A and 11B is depicted, other suitable implementations
may also be used, which may include features alternative or additional to those described
above.
[0102] A processor 602 in the key circuit 600 is in communication with a memory device 626,
similar to the processor 502 and the memory device 526 of the key circuit 510. In
the depicted embodiment, the processor 602 is a microcontroller and the memory device
626 is a flash memory device. While the processor 602 and the memory device 626 are
shown on both FIGURES 11A and 11B, in the depicted embodiment only one processor 602
and one memory device 626 are employed in the key circuit 600. However, in other embodiments,
multiple processors 602 and memory devices 626 may be used.
[0103] A data coil 612, shown in FIGURE 11B, is in communication with the processor 602
through conductors 604 and 606. The data coil 612 in the depicted embodiment is a
coil or solenoid which has a value of inductance (a measure of changing magnetic energy
for a given value of current). In one embodiment, the inductance of the data coil
612 is 100 µH (micro-Henries). In certain embodiments, the data coil 612 sends data
to and receives data from a lock circuit 700 (shown in FIGURE 12).
[0104] Transistors 616 are depicted as switches in FIGURE 11B. Similar to the switches 516,
the transistors 616 selectively direct current flow between the data coil 612 and
the processor 602. Control signals sent on conductors 662 from the processor 602 selectively
allow current to flow through the transistors 616. When the transistors 616 are activated
by control signals from the processor 602, and when the processor 602 is sending signals
to the data coil 612, the data coil 612 transmits the data. Alternatively, when the
data coil 612 is receiving data, the transistors 616 in conjunction with other circuit
components direct the data to the processor 602 through the ACDATA line 664. Consequently,
the key circuit 600 can both send and receive data on the data coil 612.
[0105] Various encoding schemes may be used to transmit and receive data. For example, a
Manchester encoding scheme may be used, where each bit of data is represented by at
least one voltage transition. Alternatively, a pulse-width modulation scheme may be
employed, where a signal's duty cycle is modified to represent bits of data. Using
different encoding schemes may allow the key circuit 600 to contain fewer components.
For example, when a pulse-width modulation scheme is used, such as in FIGURES 13A
and 13B below, fewer transistors 616 may be employed. By employing fewer components,
the key circuit 600 of certain embodiments may be reduced in size, allowing a corresponding
key assembly to be reduced in size. In addition, using a relatively simple modulation
scheme such as Manchester encoding or pulse-width modulation reduces the need for
filters (e.g., low-pass filters), thereby further reducing the number of components
in the key circuit 600.
[0106] A power coil 614 is in communication with the processor 604 through conductors 608
and 610 (see FIGURE 11B). In one embodiment, the inductance of the power coil 612
is 10 µH (micro-Henries). Like the power coil 514 of FIGURE 10, the power coil 614
in certain embodiments transmits power to the lock circuit 700 described in connection
with FIGURE 12, below.
[0107] In the depicted embodiment, the processor 602 generates two oscillating signals which
are provided to the power coil 614. In the depicted embodiment, the oscillating power
signals oscillate at 200 kHz (kilohertz). The relative high frequency of the power
signal in certain embodiments facilitates improved rectification of the power signal
and therefore a more efficient power transfer. In alternative embodiments other frequencies
may be chosen without departing from the scope of the inventions described herein.
[0108] In one embodiment, the power signals sent over power coil 614 oscillate at a higher
frequency than the data signals sent over the data coil 612. When the power signals
oscillate at a higher frequency than the data signals, interference between power
and data signals is further minimized, e.g., the signal-to-noise ratio (SNR) is improved.
In one embodiment, significant SNR improvements occur when the power signal frequency
is greater than 10 times the data signal frequency.
[0109] Diodes 620 are in communication with the power coil 614 through conductors 608 and
610. The diodes 620 in the depicted embodiment form a rectifier circuit, similar to
the rectifier circuit 520 of FIGURE 10. The depicted configuration of the diodes 620
constitutes a bridge rectifier, or full wave rectifier. The bridge rectifier receives
power from the power coil 614 when, for example, the key circuit 600 is in communication
with a docking station. In such instances, the diodes 620 of the bridge rectifier
in conjunction with a capacitor 684 convert an incoming AC signal into a DC signal.
This DC signal is denoted by voltage Vpp 682 in the depicted embodiment.
[0110] The voltage Vpp 682 is provided to a recharge circuit 622 (see FIGURE 11A). The recharge
circuit 622 recharges a battery 624 using Vpp 682. The battery 624 outputs a voltage
Vcc 696, which is sent to various components of the key circuit 600 including to a
voltage regulator 690. The voltage regulator 690 provides a constant voltage to a
supervisory circuit 692, which is in communication with a backup battery 694. If the
battery 624 fails, in certain embodiments, the supervisory circuit 692 provides power
to the circuit through the backup battery 694. Consequently, data stored in the memory
device 626 is protected from loss by the supervisory circuit 692 and by the backup
battery 694.
[0111] FIGURE 12 depicts a specific implementation of a lock circuit, generally referred to by the
reference numeral 700, which is substantially similar in structure and function to
the lock circuit 530 described above. The lock circuit 700 includes a processor 746.
The processor 746, like the processor 602, is a microcontroller. The processor 746
communicates with a memory device 748, which in the depicted embodiment is a flash
memory. Although the specific implementation of the lock circuit 700 illustrated in
FIGURE 12 is one implementation of the lock circuit 530, other suitable implementations
may also be used, which may include alternative or additional features to those described
above.
[0112] In the lock circuit 700, a data coil 732 is in communication with the processor 746
through conductors 736 and 738. The data coil 732 in the depicted embodiment is a
coil or solenoid which has a value of inductance. In one embodiment, the inductance
of the data coil 732 is 100 µH (micro-Henries). The data coil 732 receives data from
and sends data to the data coil 612 of the key circuit 600.
[0113] In one embodiment, data provided by the key circuit 600 and received by the data
coil 732 provides a clock signal to the processor 746, enabling the processor 746
to be synchronized or substantially synchronized with the processor 602 of the key
circuit 600. The clock signal may be provided, for example, when a Manchester encoding
scheme is used to transmit the data. In certain embodiments, this external clock signal
removes the need for a crystal oscillator in the lock circuit 700, thereby reducing
the number of components and therefore the size of the lock circuit 700.
[0114] Transistors 744 are depicted as switches. Similar to the switches 544, the transistors
744 selectively direct current flow between the data coil 732 and the processor 746.
Control signals sent on conductor 782 from the processor 746 control the transistors
744, selectively allowing current to flow through the transistors 744.
[0115] A power coil 734 is in communication with the processor 746 through conductors 740
and 742. In one embodiment, the inductance of the power coil 734 is 10 µH (micro-Henries).
Like the power coil 532 of FIGURE 10, the power coil 734 in certain embodiments receives
power from the key circuit 600. In the depicted embodiment, the power coil 734 provides
an AC voltage signal to power conversion circuit 750.
[0116] Power conversion circuit 750 includes diodes 720, a capacitor 790, and a low-dropout
regulator 760. The diodes 720 of the power conversion circuit 750 form a rectifier
circuit. The depicted configuration of the diodes 720 constitutes a bridge rectifier,
or full wave rectifier. When the diodes 720 receive an AC voltage signal from the
power coil 734, the diodes 720 of the bridge rectifier full-wave rectify the AC voltage
signal. This full-wave rectified signal in certain embodiments still contains a changing
voltage signal with respect to time, but the voltage signal has a single polarity
(e.g., the entire voltage signal is positive). This full-wave rectified signal is
provided as voltage Vcc 784 to a solenoid 752.
[0117] The capacitor 790 converts the full-wave rectified signal into DC form and provides
the DC signal to the low-dropout regulator 760. The low-dropout regulator 760 stabilizes
the signal to a voltage Vdd 772, which is provided to various components in the lock
circuit 700, including the processor 746. Consequently, the power conversion circuit
750 provides a changing or AC voltage Vcc 784 to the solenoid 752 and a DC voltage
Vdd 772 to various circuit components.
[0118] The solenoid 752 receives the voltage Vcc 784 from the power converter 750. The solenoid
752 in one embodiment is a coil containing one or more windings. The solenoid 752,
upon receiving the voltage Vcc 784 from the power converter 550, generates a magnetic
field to actuate an unlocking mechanism in a lock, in a manner similar to that which
is described above.
[0119] A transistor 754 is in communication with the solenoid 752. The transistor 754 is
also in communication with the processor 746 through a conductor 780. In addition,
the transistor 754 is in communication with ground 778. In certain embodiments, the
transistor 754 acts as a switch to enable or disable the solenoid 752 from receiving
current, thereby causing the solenoid 752 to lock or unlock the locking device. In
one embodiment, the processor 746 sends a signal through the conductor 780 to the
transistor 754 that sends current through the transistor 754 and thereby creates a
conduction path from the solenoid 752 to ground 778. With the transistor 754 in this
state, the solenoid 752 is able to receive current from the voltage Vcc 784 and thereby
effectuate unlocking. However, at other times, the processor 746 will not send a signal
780 to the transistor 754, such as when the processor 746 did not receive a correct
unlocking code. In such case, the processor 746 causes the transistor 754 to remain
open, thereby preventing current from flowing through the solenoid.
[0120] FIGURES 13A and 13B depict another specific implementation of a key circuit, referred
to by the reference numeral 800, which is substantially similar in structure and function
to the key circuit 600 described in FIGURES 11A and 11B above. In certain embodiments,
certain elements of the key circuit 600, such as circuit components 860, 872, and
874 (shown in FIGURE 13B), may also be employed in a corresponding lock circuit (not
shown).
[0121] In the depicted embodiment, circuit components 860, 872, and 874 in conjunction with
a processor provide circuitry for a pulse-modulation data-encoding scheme. During
transmission of data from the key circuit 800, transistor switches 860 are selectively
switched on and off to pulse a data signal to a data coil. When the key circuit 800
is receiving data, the comparator 872 receives the data voltage signal from the data
coil.
[0122] The comparator 872 is used to convert the data voltage signal into a two-bit digital
signal which is sent to a processor via data input line 880. In addition, the comparator
872 (or an operational amplifier used as a comparator) may be used to amplify the
voltage signal to a level appropriate for a processor to manipulate.
[0123] A feedback resistor 874 provides positive feedback to the comparator 872, such that
the comparator 872 attenuates small voltage signals and amplifies large voltage signals.
By attenuating and amplifying small and large voltage signals respectively, the comparator
872 and feedback resistor 874 reduce the oscillatory effects of noise on the comparator
872. Thus, wrong-bit detection errors are reduced. In alternative embodiments, a Schmitt
trigger integrated circuit may be employed in place of the comparator 872 and the
resistor 874.
IV. Holding Coil Embodiments
[0124] The cartridge 106 described above includes, in certain embodiments, a single solenoid
122 used for movement of the slide bars 128 (see, e.g., FIGURE 4). Excitation of the
solenoid 122 can create magnetic fields that cause the slide bars 128 to move away
from the extensions 131 of the bolt 130, allowing the lock to be actuated. However,
in some implementations, exciting the solenoid 122 with enough energy to move the
slide bars 128 can consume a substantial amount of current.
[0125] Keeping the slide bars 128 spaced from the solenoid 122 may also expend current.
As the slide bars 128 move farther from the solenoid 122, the magnetic field loses
intensity because the field strength of a magnet can decrease proportionally to 1/r
3, where r is the distance from the face of the magnet. As a result, the farther the
slide bars 128 are from the solenoid 122, the more current may be expended to keep
the slide bars 128 spaced from the solenoid 122.
[0126] Conversely, the smaller r is, the stronger the magnetic field strength can be. Thus,
in certain embodiments, one or more holding coils may be provided to assist the solenoid
122 with moving and/or holding the slide bars 128 (see FIGURES 14 through 16). The
one or more holding coils may be positioned to reduce r from at least one face of
a slide bar. Advantageously, in certain implementations, the one or more holding coils
can therefore reduce the current used to move and/or hold the slide bar or bars by
an order of magnitude or more. In one implementation, for example, the current usage
is 1/15th or less of the current used by the solenoid 122 described above. Current
savings provided by the one or more holding coils can enable use of a smaller power
supply, among other benefits (see, e.g., FIGURE 19A).
[0127] Turning to
FIGURES 14A through
14C, several views of embodiments of a coil assembly 900 having holding coils are shown.
In particular,
FIGURE 14A illustrates a side perspective view of the coil assembly 900,
FIGURE 14B illustrates a front view of the coil assembly 900, and
FIGURE 14C illustrates a cross-sectional side view of the coil assembly 900 taken along the
line 14C-14C in
FIGURE 14B.
[0128] The coil assembly 900 may be used in conjunction with some or all of the lock assemblies
described above. For example, the coil assembly 900 can be used in the lock 100 described
above in place of one or more of the cartridge 106, solenoid 126, and slide bars 128,
among possibly other things. Alternatively, the coil assembly 900 may be used in a
different lock assembly. One embodiment of a lock assembly that could use the coil
assembly 900 is described below with respect to FIGURE 21.
[0129] Referring specifcally to
FIGURE 14A, the coil assembly 900 includes a cartridge 906, which may include some or all of
the features of the cartridge 106 described above. Likewise, the coil assembly 900
includes a primary coil 922 positioned around the cartridge 906. The primary coil
922 may include some or all of the features of the solenoid 126 described above. The
coil assembly 900 also includes two holding coils 940a, 940b for assisting with moving
and/or holding slide bars 928a, 928b (FIGURE 14C).
[0130] Each of the coils 922, 940a, 940b includes one or more windings of wire wrapped around
the cartridge 906. The holding coils 940a, 940b are spaced from the primary coil 922
in the depicted embodiment. Other configurations than shown may be used, such as wires
wrapped partially around the cartridge 906. Also not shown, but which may be included,
are connections to a circuit for controlling the coils 922,940a, 940b. An example
circuit for controlling the coils 922, 940a, 940b is described below with respect
to FIGURE 17. In addition, some or all of the circuitry described above with respect
to FIGURES 10 through 13 may be used or adapted to control the coils 922, 940a, 940b.
[0131] The cartridge 906 includes a body portion 908 and extension receiving portions 920.
The body portion 908 preferably is cylindrical or substantially cylindrical. The extension
receiving portions 920 protrude from the body portion 908 and are likewise preferably
cylindrical or substantially cylindrical. Non-cylindrical configurations of the body
and extension receiving portions 908, 920 may be used in other embodiments. The extension
receiving portions 920 may be used to receive extensions of a locking mechanism (see,
e.g., FIGURES 4 and 14-16). For example, the extensions of a locking mechanism may
slide along one or more surfaces 938 of the extensions 920 or otherwise extend into
and/or pass through the extensions 920 (FIGURE 14C).
[0132] Referring to
FIGURE 14C, the body portion 908 in the depicted embodiment houses a core 950 and slide bars
928a, 928b. The core 950 may be made of a soft metal material, such as iron, for example
but without limitation. The core 950 is disposed within the body 908 of the cartridge
such that the core 950 is also positioned within the primary coil 922. As such, the
core 950 may serve to increase the inductance of the primary coil 922 when the primary
coil 922 is energized 922. Some implementations may not include the core 950. In the
illustrated configuration, the core 950 is substantially axially coextensive with
the primary coil 922. Other configurations may be possible.
[0133] In an implementation, the primary coil may have an inductance of about 15 µH without
the core 950. Addition of the iron core 950 may increase this inductance by orders
of magnitude, such as 500 times or more. The inductance of the holding coils 940a,
940b may be, in one implementation, about 8 to 10 µH. However, the inductance values
provided here are mere examples. The inductance characteristics of the various coils
922, 940a,940b may vary widely depending on, among other things, the size of the coils
922,940a, 940b.
[0134] The slide bars 928a, 928b may include a magnetic material, such as neodymium, powdered
metal, steel, iron, an alloy, combinations of the same, or the like. In an embodiment,
the slide bars 928a, 928b include all the features of the slide bars 128 described
above. The slide bars 928a, 928b may move slidably along or within some or all inner
surfaces 912a, 912b of the body portion 908, respectively. For example, the slide
bars 928a, 928b may slide away from the core 950 in response to excitation of the
primary coil 922 and/or excitation of the holding coils 940a, 940b. The slide bars
928a, 928b may come to rest against outer walls 954a, 954b of the body portion 908.
Likewise, the slide bars 928a, 928b may slide toward the core 950 in response to reduced
or no excitation of the primary coil 922 and/or holding coils 940a, 940b. The slide
bars 928a, 928b may come to rest against inner walls 952a, 952b on each side of the
core 950, which greatly reduces the likelihood of the slide bars 928a, 928b actually
touching the core 950. However, the walls 952a, 952b and 954a, 954b might not be provided
in other embodiments. In some embodiments, the walls 952a, 952b and 954a, 954b are
solid. In some embodiments one or more of the walls 952a, 952b and 954a, 954b may
comprise openings or apertures or the like.
[0135] In the depicted embodiment, the slide bars 928a, 928b are each about the same length
as the length of the holding coils 940a, 940b. In certain embodiments, this common
length between the slide bars 928a, 928b and the holding coils 940a, 940b may result
in the holding coils having a desired holding strength. If the lengths of the holding
coils 940a, 940b and the slide bars 928a, 928b do not match, more current might be
used by the holding coils 940a, 940b to assist with moving and/or holding the slide
bars 928a, 928b. However, other configurations of the slide bars 928a, 928b and holding
coils 940a, 940b may be used, including configurations where the lengths are different.
[0136] Moreover, many variations of the coil assembly 900 may be used in other implementations.
For instance, there may be one extension receiving portion 920 and one holding coil
940a, 940b. Also, more than two holding coils 940a, 940b and/or extension receiving
portions 920 may be provided.
[0137] FIGURES 15A through
15C illustrate the coil assembly 900 in the context of a lock assembly 1000.
FIGURE 15A depicts a locked position of the lock assembly 1000,
FIGURE 15B depicts an unlocking position of the lock assembly 1000, and
FIGURE 15C depicts an unlocked position of the lock assembly 1000. Each of FIGURES 15A, B, and
C is also a cutaway view of a portion of a lock, such as the lock of FIGURE 21 below.
[0138] The lock assembly 1000 includes a case 924 that houses the coil assembly 900. The
lock assembly 1000 also includes a locking mechanism 929, which includes a bolt 930,
extensions 931 from the bolt 930, and springs 932. The bolt 930 may function in the
same or similar manner as the bolt 130 described above. For example, the bolt 930
may have a chamfered lower edge (not shown) that mates with a groove of the lock (see,
e.g., FIGURE 3). Springs 932 tend to urge the bolt 930 into a locked position.
[0139] In the locked position shown in
FIGURE 15A, the slide bars 928a, 928b are attracted to the core 950 and therefore rest against
the inner walls 952a, 952b. In the depicted embodiment, the core 950 is not magnetized
or may be slightly magnetized. Example polarizations (e.g., "+" and "-") are depicted
on the slide bars 928a, 928b. These polarizations may be reversed in other embodiments.
In the unlocking position depicted in
FIGURE 15B, the primary coil 922 has been energized, causing a magnetic field to magnetize the
core 950. Thus, example polarizations are illustrated on the core 950. These polarizations
can cause the slide bars 928a, 928b to move away from the core 950.
[0140] Each holding coil 940a, 940b may be energized in certain embodiments when a corresponding
slide bar 928a, 928b has passed within at least half of the axial length of the holding
coil 940a, 940b. In an embodiment, the holding coils 940a, 940b are energized this
way because the polarization (not shown) of each holding coil 940a, 940b can have
the same orientation as the polarization of the corresponding slide bar 928a, 928b.
Consequently, if the holding coils 940a, 940b were to energize before the slide bars
928a, 928b passed at least halfway within the holding coils 940a, 940b, the holding
coils 940a, 940b might repel the slide bars 928a, 928b toward the core at 950.
[0141] In certain embodiments, a timer is used as a proxy to determine when the slide bars
928a, 928b have passed at least halfway through the holding coils 940a, 940b. The
timer may be implemented in hardware and/or software (see FIGURE 17). The amount of
time used by the timer to determine whether to energize the holding coils 940a, 940b
may be determined experimentally. In one embodiment, the timer is configured such
that the holding coils 940a, 940b are activated when slightly more than 50% of the
slide bars 928a, 928b have passed through the holding coils 940a, 940b. In another
implementation, the timer is configured such that the holding coils 940a, 940b are
activated when about 60% or more of the slide bars 928a, 928b have passed through
the holding coils 940a, 940b. Alternatively, each holding coil 940a, 940b may be activated
when 100% or substantially 100% of the corresponding slide bar 928a, 928b has passed
through the holding coil 940a, 940b. For example, the holding coils 940a, 940b may
be activated in response to the slide bars 928a, 928b contacting the outer walls 954a,
954b. The values described herein are mere examples, and others may be used in other
implementations.
[0142] Once the holding coils 940a, 940b have energized, the magnetic field generated by
the holding coils 940a, 940b can assist the slide bars 928a, 928b with moving away
from the core 950 if the slide bars 928a, 928b have not been moved a sufficient distance
toward the outer walls 954a, 954b to allow passage of the corresponding extensions
931. Additionally, the holding coils 940a, 940b can hold the slide bars 928a, 928b
in a resting or substantially resting position, as shown in
FIGURE 15C. In this position, the slide bars 928a, 928b are no longer blocking the extensions
931 of the bolt 930, thereby allowing actuation of the locking mechanism 929. For
example, movement of the extensions 931 into the body 908 of the cartridge 906 is
now possible due to the movement of the slide bars 928a, 928b.
[0143] The primary coil 922 may be deactivated in response to the holding coils 940a, 940b
being energized. For example, a control circuit (see FIGURE 17) may stop the flow
of current through the primary coil 922 at the same time as the holding coils 940a,
940b are energized or slightly thereafter. The control circuit might also deenergize
the primary coil 922 in response to a portion of or the entire slide bars 928a, 928b
passing through the holding coils 940a, 940b. The holding coils 940a, 940b may be
energized for enough time to allow a user to actuate the locking mechanism 929. After
a predefined time of, for example, two or three seconds, the holding coils 940a, 940b
may be deenergized to conserve power. Many other configurations may also be used.
[0144] In certain embodiments, the distance r from the slide bars 928a, 928b and the energized
primary coil 922 is reduced. In other words, because the holding coils 940a, 940b
may assist with moving and/or holding the slide bars 928a, 928b, the primary coil
922 does not need to push the slide bars 928a, 928b as great of a distance "r" in
certain embodiments. Current may therefore be reduced by using the holding coils 940a,
940b.
[0145] To further illustrate example operation of the primary coil 922 and holding coils
940a, 940b,
FIGURES 16A through
16C illustrate example models of magnetic fields in the context of the lock assembly
of FIGURES 15A through 15C.
FIGURE 16A depicts the locked position of the lock assembly 1000,
FIGURE 16B depicts the unlocking position of the lock assembly 1000, and
FIGURE 16C depicts the unlocked position of the lock assembly 1000. Hatch marks have been removed
to more clearly depict the magnetic fields.
[0146] The magnetic fields include slide bar fields 1010a, 1010b, a primary coil field 1020,
and holding coil fields 1030a, 1030b. In the locked position of
FIGURE 16A, the slide bar fields 1010a, 1010b of the slide bars 928a, 928b attract the slide
bars 928a, 928b to the core 950. The unlocking position of
FIGURE 16B shows that in response to the primary coil 922 being energized, the primary coil
field 1020 is produced, which repels the slide bars 928a, 928b toward the holding
coils 940a, 940b.
FIGURE 16C illustrates the slide bars 928a, 928b having passed within the holding coils 940a,
940b. In this unlocked position, the holding coil fields 1030a, 1030b are energized
for a time. The primary coil field 1020 is deactivated but may alternatively be reduced
in the unlocked position.
[0147] Although the holding coil fields 1030a, 1030b are shown when the slide bars 928a,
928b have passed within the holding coils 940a, 940b, the holding coil fields 1030a,
1030b may also be present when the slide bars 928a, 928b are moving toward the holding
coils 928a, 928b.
[0148] FIGURE 17 illustrates an embodiment of a control circuit 1100 for actuating the coil assembly
of FIGURES 14 through 16. The control circuit 1100 may be included, for example, in
the circuit board 134 or the like (see FIGURE 3). In certain embodiments, the control
circuit 1100 may be used in conjunction with the circuits described above with respect
to FIGURES 10 through 13.
[0149] The control circuit 1100 includes a primary coil 1122 and holding coils 1140a, 1140b.
The primary coil 1122 is in communication with a switch 1112. Likewise, the holding
coils 1140a, 1140b are in communication with a switch 1118. A second switch may be
provided in some implementations so that each holding coil is in communication with
a separate switch. The switches 1112, 1118 may include transistors, such as MOSFETs
or the like. A processor 1102 controls both the switch 1112 and the switch 1118. The
processor 1102 may be, for example, the same processor as the processor 502 described
above.
[0150] The processor 1102 may include software and/or firmware for controlling the switches
1112, 1118. For instance, the processor 1102 may include a timer and associated logic
for determining a sequence and/or duration for actuating the switches 1112, 1118.
The processor 1102 may selectively actuate the switches 1112, 1118 in response to
instructions received from an electronic key, such as the key of FIGURE 5 or FIGURE
19A. Alternatively, a separate hardware timer may be provided.
[0151] In response to the switch 1112 being actuated, power from a capacitor 1116 may be
provided to the primary coil 1122. The capacitor 1112 is used in some embodiments
to provide a rapid burst of current. The capacitor 1116 is charged by a power supply
1114, which may receive power from the power coils described above. A tantalum capacitor
1116 may be used for its high charge to size ratio, although other types of capacitors
may also be used. The primary coil 1122 may instead be powered directly by the power
supply 1114 in some implementations.
[0152] The capacitor 1116 may energize the primary coil 1122 for a relatively short period
of time, such as a few milliseconds or the like. As the primary coil 1122 is energized,
the slide bars 928a, 928b may be repelled and move toward the holding coils, as described
above. As the energy of the capacitor 1116 dissipates, or when the processor 1102
opens the switch 1122, the magnetic field generated by the primary coil 1122 may also
dissipate. In response, the processor 1102 may actuate the switch 1118, causing power
from the power supply 1114 (or from another capacitor) to actuate the holding coils
1140a, 1140b. After a predetermined period of time, such as two or three seconds,
the processor 1102 may open the switch 1118 and deactivate the holding coils 1140a,
1140b.
[0153] In an embodiment, a capacitance value of the capacitor 1116 is selected such that
the capacitor 1116 dissipates its energy in a sufficient amount of time for the primary
coil 1122 to be energized. Thus, a separate timer may not be used to control the primary
coil 1122.
[0154] In alternative embodiments, the processor 1102 may perform other sequences. For instance,
the processor 1102 may close the switch 1118 before closing the switch 1112. Or, the
processor 1102 might close both the switches 1112, 1118 at the same time, among other
possible sequences.
[0155] FIGURE 18 illustrates an embodiment of a process 1200 for actuating the coil assembly of FIGURES
14 through 16. The process 1200 may be implemented by the control circuit 1100 described
above. The process 1200 may be used to unlock a multi-coil lock assembly. In an embodiment,
the process 1200 is performed in response to the control circuit 1100 receiving unlocking
instructions from an electronic key.
[0156] At block 1202, a first coil positioned around a cartridge of a lock assembly is energized.
The first coil may be the primary coil 922, 1122 described above. The first coil may
be energized, for example, by the processor 1102 causing power from a power supply
and/or capacitor to be provided to the first coil. The energizing of the fist coil
may generate a magnetic field.
[0157] The magnetic field from the first coil may be used at block 1204 to repel a barrier
in the cartridge. The barrier can be one or more slide bars, such as the slide bars
928a, 928b described above. When magnetically attracted to a core of the cartridge
(e.g., the core 950), the barrier can act to block the locking mechanism 929 from
moving into the cartridge, thereby maintaining a locked position of the lock assembly.
[0158] At block 1206, a second coil positioned around the cartridge and spaced from the
first coil is energized. This block 1206 may be performed by the processor 1102 causing
power from a power supply and/or capacitor to be provided to the second coil. The
second coil may be one of the holding coils 940a, 940b described above. Energizing
of the second coil may cause a magnetic field to be generated in the second coil.
The magnetic field from the second coil may be used at block 1208 to attract the barrier,
such that the locking mechanism 929 that was in communication with the barrier is
now allowed to move.
[0159] The process 1200 has been described in the context of a single holding coil. However,
the process 1200 may also be implemented with lock assemblies that include multiple
holding coils, such as two holding coils.
V. Shear Pin Embodiments
[0160] In some cases, an individual might attempt to break open the locks described above
by applying a torque to a key when the key is mated with a lock. To reduce the chance
of the lock breaking open, one or more shear pins may be provided in the key and/or
in the lock. Upon application of sufficient torque, the one or more shear pins can
break, allowing the key to turn freely within the lock. As a result, the shear pins
can prevent or reduce the chance of the locking mechanism breaking open. In addition,
the one or more shear pins may be easily replaceable.
[0161] FIGURE 19A illustrates an isometric perspective view of an embodiment of a key 1300 having shear
pins 1332. The key 1300 may include some or all of the features of the keys described
above. The key 1300 includes an elongate main body portion 1302 that is generally
rectangular in cross-sectional shape. The illustrated key 200 also includes a mating
portion 1312 of smaller external dimensions than the body portion 1302.
[0162] The body portion 1302 can house the internal electronics of the key 1300 as well
as other components. Advantageously, in certain embodiments, the body portion 1302
of the key 1300 is smaller than the body portion of the key 200 described above. This
reduction in size may be made possible at least in part by using fewer batteries in
the key 1300. Fewer batteries may be used, in certain embodiments, because the holding
coils described above may reduce current usage by the lock and/or key.
[0163] The mating portion 1312 can engage a lock described below with respect to FIGURE
19B. The mating portion 1312 includes a cylindrical portion 1310 that houses a power
coil 1320 and data coil (not shown). On the outer surface of the cylindrical portion
are two tabs 1314 which can rotationally engage the key 1300 relative to the lock
(see FIGURE 19B). These tabs 1314 extend radially outward from the outer surface of
the cylindrical portion 1310 and oppose one another.
[0164] The cylindrical portion 1310 includes a recess 1318 that opens to the front of the
key 1300. Located within the recess 1318 is the power coil 1320 and data coil (not
shown) described above. In addition, two shear pins 1332 are located within the recess.
Each shear pin 1332 is embedded partially in a wall 1311 of the cylindrical portion
1310. The shear pins 1332 are generally cylindrical in shape. Other configurations
may be possible. The shear pins 1332 are located opposite each other in the cylindrical
portion 1310. Although two shear pins 1332 are shown, fewer or more shear pins may
be provided in alternative embodiments.
[0165] The shear pins 1332 may assist with mating the key 1300 to a lock.
FIGURE 19B depicts an embodiment of such a lock 1400. The lock 1400 may include some or all
of the features of the locks described above. The lock 1400 advantageously allows
the shear pins 1332 of the key 1300 to mate with the lock 1400 in certain embodiments,
such that attempted breaking of the lock 1400 via sufficient torque can result in
breaking of the shear pins 1332. When the shear pins 1332 break, the key 1300 may
rotate freely in the lock 1400 and thereby be unable to actuate the locking mechanism.
[0166] The lock 1400 includes a body portion 1404 and a mating portion 1408. The body portion
1404 may at least partly house one of the coil assemblies described above. The diameter
of the mating portion 1408 is larger than the diameter of the body portion 1404.
[0167] The mating portion 1408 includes a cylinder 1446 and a raised cylindrical portion
1460 disposed within the cylinder 1446. An annular groove 1448 or key recess is formed
between the cylinder 1446 and the raised cylindrical portion 1460. The annular groove
1448 is capable of receiving the tabs 1314 of the key 1300. A cup 1452 is disposed
within the raised cylindrical portion 1460, which is capable of receiving the power
coil 1320 of the key 1300. The raised cylindrical portion 1460 also includes shear
pin slots 1462, which can receive the shear pins 1332 of the key 1300. The shear pin
slots 1462 are concave in the depicted embodiment to facilitate placement of the shear
pins 1332 and removal of broken shear pins. The number of shear pin slots 1462 may
correspond to the number of shear pins 1332 on the key. In some embodiments, more
slots may be provided than shear pins. The shear pin slots 1462 may be enclosed, rather
than concave, in some embodiments.
[0168] In certain implementations, the key 1300 may mate with the lock 1400 by placement
of the tabs 1314 in the annular groove 1442, by placement of the power coil 1320 in
the cup 1452, and by placement of the shear pins 1332 in the shear pin slots 1462.
The key 1300 may provide data to the lock 1400, allowing a locking mechanism of the
lock 1400 to be actuated. The key 1300 may then be turned by an operator of the key.
As the shear pins 1332 grip against the walls of the shear pin slots 1462, the shear
pins 1332 may turn the raised cylindrical portion 1460, causing the locking mechanism
to actuate. The tabs 1314 of the key 1300 may slide under tabs 1470 of the lock 1400.
Locking may proceed, for example, by turning the key 1300 in a reverse motion.
[0169] If, however, the key 1300 does not provide suitable data to the lock 1400 (e.g.,
because the operator of the key 1300 does not have a suitable combination), the locking
mechanism of the lock 1400 does not actuate. If the operator of the key 1300 attempts
to turn the key with enough force to break the locking mechanism, the shear pins 1332
may shear instead. With the shear pins 1332 broken, turning of the key 1300 may no
longer be able to turn the raised cylindrical portion 1460, thereby preventing actuating
of the locking mechanism.
[0170] Further detail of the shear pins 1332 is shown in
FIGURE 20, which is a cross-sectional view of the key 1300 along the section lines shown in
FIGURE 19A. In
FIGURE 20, the shear pins 1332 are depicted extending past a surface 1392 at the bottom of the
recess 1318. More than half of each shear pin 1332 extends below the surface 1392.
The amount that the shear pins 1332 extend past the surface 1392 may vary in some
embodiments. The shear pins 1332 may, for instance, not extend below the surface 1392
at all.
[0171] FIGURE 21 illustrates a side cross-section view of an embodiment of the lock 1400, taken along
the line 21-21 in FIGURE 19B. The raised cylindrical portion 1460 of FIGURE 19B has
been rotated 90 degrees for clarity, so as to show the shear pin slots 1462.
[0172] The body portion 1404 of the lock 1400 is shown to the right of the FIGURE, and the
mating portion 1408 is to the left. The lock assembly 1000, including the coil assembly
900, is included in the body portion of the lock 1400. In the depicted embodiment,
the coil assembly 900 is not axially aligned with the axis of the lock 1400, unlike
the lock 100 described above. Rather, the coil assembly 900 is offset from the axis.
This non-axial alignment may allow a larger bolt 930 to be included in the lock 1400.
In other embodiments, the coil assembly 900 may be axially aligned with the lock 1400.
VI. Conclusion
[0173] While various embodiments of key and lock circuits have been depicted, the various
illustrative logical blocks, modules, and processes described herein may be implemented
as electronic hardware, computer software, or combinations of both. To clearly illustrate
this interchangeability of hardware and software, various illustrative components,
blocks, modules, and states have been described above generally in terms of their
functionality. However, while the various modules are illustrated separately, they
may share some or all of the same underlying logic or code. Certain of the logical
blocks, modules, and processes described herein may instead be implemented monolithically.
[0174] The various illustrative logical blocks, modules, and processes described herein
may be implemented or performed by a machine, such as a computer, a processor, a digital
signal processor (DSP), an application specific integrated circuit (ASIC), a field
programmable gate array (FPGA) or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination thereof designed
to perform the functions described herein. A processor may be a microprocessor, a
controller, microcontroller, state machine, combinations of the same, or the like.
A processor may also be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of microprocessors or processor
cores, one or more graphics or stream processors, one or more microprocessors in conjunction
with a DSP, or any other such configuration.
[0175] The blocks or states of the processes described herein may be embodied directly in
hardware, in a software module executed by a processor, or in a combination of the
two. For example, each of the processes described above may also be embodied in, and
fully automated by, software modules executed by one or more machines such as computers
or computer processors. A module may reside in a computer readable medium such as
RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard
disk, a removable disk, a CD-ROM, memory capable of storing firmware, or any other
form of computer-readable (e.g., storage) medium known in the art. An exemplary computer-readable
medium can be coupled to a processor such that the processor can read information
from, and write information to, the computer-readable medium. In the alternative,
the computer-readable medium may be integral to the processor. The processor and the
computer-readable medium may reside in an ASIC.
[0176] Depending on the embodiment, certain acts, events, or functions of any of the processes
or algorithms described herein can be performed in a different sequence, may be added,
merged, or left out all together. Thus, in certain embodiments, not all described
acts or events are necessary for the practice of the processes. Moreover, in certain
embodiments, acts or events may be performed concurrently, e.g., through multi-threaded
processing, interrupt processing, or via multiple processors or processor cores, rather
than sequentially.
[0177] Conditional language used herein, such as, among others, "can," "could," "might,"
"may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood
within the context as used, is generally intended to convey that certain embodiments
include, while other embodiments do not include, certain features, elements and/or
states. Thus, such conditional language is not generally intended to imply that features,
elements and/or states are in any way required for one or more embodiments or that
one or more embodiments necessarily include logic for deciding, with or without author
input or prompting, whether these features, elements and/or states are included or
are to be performed in any particular embodiment.
[0178] While the above detailed description has shown, described, and pointed out novel
features as applied to various embodiments, it will be understood that various omissions,
substitutions, and changes in the form and details of the logical blocks, modules,
and processes illustrated may be made without departing from the spirit of the disclosure.
As will be recognized, certain embodiments of the inventions described herein may
be embodied within a form that does not provide all of the features and benefits set
forth herein, as some features may be used or practiced separately from others. The
scope of certain inventions disclosed herein is indicated by the claims rather than
by the foregoing description. All changes which come within the meaning and range
of equivalency of the claims are to be embraced within their scope.