[0001] The-present invention generally relates to a Bayonet type socket and in particularly
relates to an improved safety socket according to the preamble of claim 1.
[0002] In the prior art, there are a variety of safety sockets of exposure type. Also, it
has become known that also buried type safety sockets are developed. These sockets
consist of at least one pair of connectors for connecting at least one plug thereto.
In these prior sockets, it is a great disadvantage that a user has to turn off at
first a power switch mounted on an electric apparatus which is connected to the socket
by a plug thereof and then has to pull out the plug from the socket for a safety handling
of the electric system, when it is needed to turn off the electric apparatus. Of course,
these two steps cause much inconvenience to the user.
[0003] For removing the above mentioned inconvenience, it is known from Japanese laid-open
Utility Model publication No. So 56-37835 that a socket of Bayonet type is provided
with a switch, which is a single pole single-throw switch, for switching on/off the
whole power connection thereto. Also, the switch can connect or disconnect only one
of the power terminals. If the technical idea is applied to a single mode socket having
only one pair of connectors this is convenient to user because of one electric apparatus
plugged-in the single mode socket. However, if the technical idea is applied to a
multiple mode socket having two or more pairs of connectors, it is no longer used
to switch off only one electric apparatus plugged-in the socket because turning off
the switch disconnects the whole electric apparatuses plugged therein. In other words,
the function of power control of the socket should be limited to only one pair of
connectors, even when teh socket consists of two or more pairs of connectors. Hereinafter,
for the convenience of the explanation, one of two terminals will be referred as an
ungrounded lead and the other as a grounded lead.
[0004] Also, in the prior art sockets, the grounded power line and the ungrounded power
line are directly connected to the grounded one and ungrounded one respectively and
only one of the power lines can be switched on/off, so that even when the switch is
turned off, the other power line remains always directly connected to the corresponding
lead. Thus, there are always safety problems and especially the danger of an electric
shock to a child or an infant, when they put a finger or an iron stick held in the
hand into the socket eyes.
[0005] It is therefore an object of the present invention to provide for a safety socket
including at least two pairs of connectors avoiding the above mentioned problems in
particular, the safety socket is to prevent from electric shocks even when some connectors
are used while other connectors are not used.
[0006] It is also desirable to provide for a safety socket having a number of indicators
corresponding to the number of pairs of connectors, which can display it there is
an electric voltage applied to.
[0007] This object is solved by the features of claim 1. Further developments and embodiments
of the invention are given in the subclaims.
[0008] The present invention provides for a safety socket for conveniently controlling the
connected electric apparatus without pulling out of the plugs thereof.
[0009] Other detailed features and advantages of the instant invention will become apparent
from the accompanying drawings taken in conjunction with the detailed description
of the presently preferred embodiments of the invention. Also it is noted that the
invention should not be limited by the described preferred embodiments in the drawings
but only by the claims which are attached.
[0010] In the drawings:
Fig. 1 is a perspective view of an embodiment of the instant invention, which includes
three pairs.of connectors, three switches and three indicators;
Fig. 2 is a plan view of inner side of an embodiment of Fig. 1 without a cover of
the socket;
Fig. 3 illustrates an operating status of double-pole single-throw switch which is
utilized in the instant invention;
Fig. 4 schematically illustrates a construction of a change over-strip which is built
in the switch of Fig. 3; and
Fig. 5 illustrates an equivalent circuit for the safety socket in Fig. 1 and Fig.
2.
[0011] Referring to Fig. 1, a safety socket of Bayonet type is perspectively illustrated
as an embodiment according to the present invention, said socket, comprising three
pairs of connectors, three double pole single throw switches and three indicators
such as a light emitting diode, a luminance tube, a neon dischange tube, etc.. The
socket consists of a base 1 and a cover 2, which is made of suitable materials such
as plastics. The cover 2 is provided with three openings for exposing three pairs
of connectors C
1, C
2, and C
3 to exterior, and also with three small openings for exposing knobs of three switches
SW
1, SW
2 and SW
3 to exterior. Between the connectors and knobs of the switches, three indicators I
1, 1
2 and I
3 are mounted.
[0012] Power input lines 3 are respectively connected through the switches SW
1, SW
2 and SW
3 to the three units A, B and C in order to control each connection of input power
thereto. Thus, each three units A, B and C are respectively controlled by the corresponding
switches SW
1, SW
2 and SW
3' respectively, so that the turning on/off of one of switches SW
1, SW
2 and SW
3 controls one power input of the connected electric apparatuses, i. e. electric loads.
[0013] Now, referring to Fig. 2, a plan view of the socket of Fig. 1 without the cover 2
is illustrated as a base 1. On the base 1, three units A, B and C are mounted. The
mechanical construction of each unit is all same. Thus, only the structure of unit
A will be described in detail hereinafter.
[0014] The unit A consists of two connectors C, switch SW
1, power supply lines Ln
1 and Lp
1 and indicator I
1. The switch SW
1 can change over the connection between the connectors C
1 and the power supply lines Ln
1 and Lp
l. The construction of the connectors C is the same as in the prior Bayonet type connectors.
The switch SW
1 is a double-pole single-throw switch and turns on/off respectively the electrical
connections between the connectors C and the power supply lines Ln
1 at the same time. The indicator I
1 may bemounted on the knob of the switch SW
1 or on the outer surface of the cover 2. Also Fig. 3 illustrates that the switch SW
1 consists of two output terminals To
1 and To
2, two input terminals Ti
1 and Ti
2 and a change over-strip 5. The output terminal To
1 is connected to one of the connectors C via the power supply line Lp
1 and then the other one of the connectors C through the power supply line Ln
l. The input terminal Ti
l is connected to a grounded line of a power source and the other terminal Ti
2 is connected to an ungrounded line of the power source and vice versa. The indicator
I
1 is connected between the output terminals To
1 and To
2.
[0015] As in Fig. 1, when the switch SW
1 is in on-position, the change over-strip 5 electrically connects the input terminals
Ti
1 and Ti
2 to the output terminals To
1 and To
2, respectively, so that the indicator I
1 is turned on so as to indicate a voltage applied to the connectors C and when the
switch SW
1 is in off-position, the change over-strip 5 respectively disconnects the electrical
connection between the input terminals Ti
1 and Ti
2 and the output terminals To
1 and To
2. Therefore, when the switch is turned off, no one of the connectors C is connected
electrical apparatus and the indicator I
1 are accordingly turned off, even when the plug of the apparatus has been inserted
into the socket. Hence, it is a great advantage that, in the condition of the turned-off
switch SW
1, even when no plug is inserted into the socket, any user, especially infants can
be fully protected from any electric shocks.
[0016] For more clearly understanding the function of the switch SW
1, the structure of the switch SW
1 will be described with reference to Fig. 3 and Fig. 4. The switch is of the push
operation type and the change over-strip 5 consists of a supporting electrically insulated
member 6 and metal strips 7 and 8. The metal strips 7 and 8 are supported securely
on the supporting insulated member 6 at both sides thereof by a proper common way.
The metal strip 7 and 8 are respectively provided with notches 9 at the intermediate
positions of the both side thereof. The notches 9 of the metal strip 7 and 8 are electrically
connected to pivot on the wall portions 10 of the input terminal Ti
1 and Ti
2.
[0017] The change over-strip 5 is formed as a bow, so that when the knob of the switch SW
1 is slided int the direction toward the output terminals, the knob may press one side
of the strip 5 so that an electric connection between the input terminals and the
output terminals can be accomplished. Accordingly, the desired voltage or current
is supplied to the connected electric apparatus and to the indicator I
1 from the power source. Although the present invention is described on the above prefered
embodiment, it is understood that the instant invention can be altered or changed
without departing from the scope thereof. For example, the invention can be adopted
to include at least two pairs of terminals of Bayonet type.
[0018] In Fig. 5, the equivalent circuit corresponding to the circuit of the safety socket
shown in Fig. 1 and 2 is depicted for more easily understanding the functional effects
of the embodiment. As shown in Fig. 5, if the switches SW
1, SW
2 and SW
3 are all turned off, the output terminals of the switches are not applied with any
potential from the power source, even when plugs of the electric apparatuses have
been inserted into the connectors of the socket, so that no power can be supplied
to the electric apparatuses from the power source. Hereby the electric disconnections
between the electric apparatuses and the socket can be held continuously without extraction
of the plugs therefrom. Therefore, this function can ensure a convenience to the user
and also a safety from the electric shock.
[0019] If all the switches SW
1, SW
2 and SW
3 are turned-on, the grounded line and ungrounded line of the power source can be extended
to the electric apparatuses and the indicator I
1, 1
2 and 1
3 through the switches and the connectors. Also the indicators I
l, I
2 and 1
3 comprise of a circuit or element R
1, R
2 and R
3 for protecting the indicators, respectively.
[0020] Then, when any one of the connected electric apparatuses has to be runed off, it
is only necessary that a switch corresponding to the apparatus is turned off.
[0021] From the above mentioned description, it will be recognized that while the instant
invention has been described as having a pretexed design, it is capable of further
modification without departing from the scope of the invention. The application therefore,
intended to cover any variations, uses, or adaptations of the instant invention following
the general principles thereof and including such depatures from the present disclosures
as come within known or customary practice in the art to which this invention pertains,
and as may be applied to the essential features hereinbefore set forth and fall within
the scope of the instant invention or the limits of the claims.
1. A safety socket characterized by a cover (2), a base (1), and at least two units
(A, B, C) consisting of one pair of connectors (C1, C2, C3), one indicator (I1, I2, 13) and a switch (SW1, SW2, SW3), respectively, the number of said switches and indicators corresponding to the number
of said pairs of connectors in said socket respectively, whereby the electrical connections
between said pairs of connectors and the connected apparatuses are able to be controlled
selectively by said switches.
2. The socket according to claim 1, characterized that said socket comprises at least
two switches (SW1. SW2, SW3) of double pole single-throw type and each of said switches consists of two input
(Ti1, Ti2) terminals connected to a power source, two output terminals (Tol, To2) connected to two connectors and one change over-strip (5).
3. The socket according to claim 1 or 2, characterized in that indicator I1, I2, I3 is mounted on each knob of said switches and the number of said indicators is the
same as the number of said switches.
4. The socket according to claims 1, 2 or 3, characterized in that each indicator
(I1, I2, I3) is located on the outer surface of said cover (2) of said socket.
5. The socket according to anyone of claims 1-4, characterized in that said switches
(SW1, SW2, SW3) are of the sliding type of a double-pole single-throw switch.
6. The socket according to anyone of claims 1-5, characterized in that said switches
(SW,, SW2, SW3) are of push-button type of double pole single-throw switch.
7. The socket according to anyone of claims 1-6, characterized in that said switches
(SW1, SW2, SW3) are of selecting type of double pole single-throw switch.
8. The socket according to claims 1 and 5, characterized in that the change over-strip
(5) of said switch (SW1, SW2, SW3) is of the bow form and consists of a body of insulating material (6) and of two
metal strips (7, 8) supported rigidly on both sides of said body.
9. The socket according to claim 8, characterized in that said change over-strip (5)
has two notches (9) on both metal strips for pivotally supporting it on wall portions
(10) of the input terminal (Til, Ti2).