GB2158662A

GB2158662A - Locking means for plug and socket assembly

Info

Publication number: GB2158662A
Application number: GB08510649A
Authority: GB
Inventors: Roger John Murphy
Original assignee: LAP TAB Ltd
Current assignee: LAP TAB Ltd
Priority date: 1984-05-11
Filing date: 1985-04-26
Publication date: 1985-11-13
Also published as: GB8510649D0; GB2158662B

Abstract

A locking means for a plug (11) and socket (13) assembly in which the plug (11) has an electrical lead (12) extending therefrom and the plug (11) and socket (13) when engaged, form an electrical connection therebetween, the locking means comprising a first member (26) engageable with the socket (13) or mountable adjacent the socket (13), and a second member (35) engageable with the first member (26) in an operative position with the plug (11) engaged with the socket (13), to prevent the plug (11) being disengaged from the socket (13), and a lock (41) to prevent the first (26) and second (35) members being disengaged from their relative operative positions. <IMAGE>

Description

SPECIFICATION Locking means for plug and socket assembly This invention relates to a locking means for a plug and socket assembly of the kind in which the plug has an electrical lead extending therefrom and the plug and socket when engaged, form an electrical connection therebetween. Such a plug and socket assembly will hereinafter be referred to as "of the kind specified".

One such assembly is used to connect a plug on the end of a lead of a telephone to a socket outlet.

Because the connection is simple and fast to disconnect, this has led to a number of thefts of telephones. Accordingly, a locking means is required to prevent the plug being disengaged from the socket and the telephone being removed by unauthorised persons. However, the invention is applicable to any plug and socket assembly such as a standard 13 amp electrical mains power socket outlet, where it is desired to prevent removal of the plug from the socket.

It is an object of the present invention to provide a locking means for a plug and socket assembly of the kind specified.

According to one aspect of the invention, we provide a locking means for a plug and socket assembly of the kind specified comprising a first member engageable with the socket or mountable adjacent the socket, and a second member engageable with the first member in an inoperative position with the plug engaged with the socket, to prevent the plug being disengaged from the socket, and a lock (as herein defined) to prevent the first and second members being disengaged from their relative operative positions.

Thus, in the case of a telephone plug and socket assembly, it would be necessary to cut the telephone lead in order to remove the telephone. As telephone plugs are usually moulded to their leads it would not be very easy to reconnect the telephone for use in another location, at least with another socket outlet, and thus the locking means would provide at least a deterrent to a thief for example.

Where the locking means is used, for example with a 13 amp electrical mains power outlet, the socket is preferably unswitched so that the lead would always be live. This would deter a thief from cutting the lead to any appliance to which the lead carries current from the socket, as the knob would risk receiving an electric shock.

By "lock" we mean a key-operable device, a combination operable device or any other device which can only be released by an authorised user having the necessary key or the like, or knowing the correct combination.

In a preferred embodiment, the socket comprises a housing having a base and a front plate secured together by fasteners such as screws or bolts, the first member of the locking means being engageable with the socket with the same fasteners that secure the front plate to the base. The second member of the locking means, at least when engaged with the first member, may include means to prevent access being gained to the fasteners so that the locking means cannot be removed as a whole from engagement with the socket, until the second member is disengaged from its operative position.

In such an embodiment, the first member may comprise a plate-like member and the second member may also comprise a plate-like member hinged to the first member, the lock, in use, preventing the second member being hinged from its operative position.

In another embodiment the first member comprises a plate-like member and the second member comprises a plate member, and the second member may be slidable into an operative position by means of co-operating guide means provided on the first and second members. In each case, the first and/or second member may have an aperture through which the lead extends, the lead becoming trapped in the aperture as the second member is moved to its operative position.

Alternatively, the second member may have an opening through which the plug may be passed when the second member is not in its operative position, but as the second member is moved to its operative position, the edges of the opening in the second member may overlie the plug to prevent its disengagement from the socket.

Alternatively, where the first member is mounted adjacent the socket, the first member may for example surround the socket and be secured by fastenings to a wall or other mounting surface, when the second member may conceal the fastenings when in its operative position. The second member may, in this embodiment, comprise a shroud to partially or completely cover the plug and socket assembly. The second member may again overlie the plug to prevent its disengagement from the socket, or alternatively the second member may engage part of the plug only, to prevent its disengagement from the socket.

According to a second aspect of the invention we provide a telephone, having a body, a lead from the body which terminates in a plug, the plug being, in use, retained in a socket and being prevented from being withdrawn therefrom by a locking means according to the first aspect of the invention, the first and second members of the locking means being in relative operative positions.

The invention will now be described with reference to the accompanying drawings, wherein: Figure l is an exploded perspective view of a first embodiment of a locking means embodying the invention in an inoperative condition and a plug and socket assembly with which the locking means is to be used; Figure 2 is a front view of the locking means and plug and socket assembly of Figure 1, in an operative condition.

Figure 3 is an exploded perspective view of a second embodiment of a locking means embodying the invention, and a socket with which the locking means may be used.

Figure 4 is a front view of the locking means and socket of Figure 3 shown assembled and in an operative position with plug received and located in the socket.

Referring first to Figures 1 and 2 of the drawings, a plug and socket assembly for a telephone 10 comprises a plug 11 which is moulded to and hence permanently connected to a lead 12 of the telephone, and a socket 13 comprising a housing having a base 14 which is secured by screws or other fastenings to a wall or other mounting surface, such as a skirting board, and a front plate 15 which with the base provides a generally box-like housing. The base 14 has internally thereof a pair of turrets 16 moulded integrally therewith, which receive screws 18, only one of which is shown in Figure 1, which pass through openings 19 in the front plate 15. In the present example, the socket 13 is a 67mm square standard telephone socket, the front plate 15 having a socket opening 20 with a resiliently biased flap 21 which automatically closes the opening 20 when the plug 11 is not engaged therein.

The invention is of course equally applicable to other sizes and types of plug and socket assemblies, examples of which are given below.

The plug 11 presents a generally rectangular front face 11', the longest side of which as drawn in Figure 1, is perpendicular to the direction the plug 11 would need to adopt to be inserted in opening 20. The plug 11 has a plurality of electrical connectors 22 which make electrical connection with corresponding connectors (not shown) inside the socket opening 20.

A locking means 25 is provided to prevent the plug 11 being removed from engagement with the socket 13 by an unauthorised person. The locking means 25 comprises a first plate-like member 26 which has an aperture 27, and a pair of holes 28 which are spaced apart the same distance as openings 19 in the front plate 15. Thus the member 26 can be secured to the front plate 15 by passing the screws 18 through holes 28 before passing them through openings 19 of the front plate 15 into the turrets 16 of the base 14. Upon tightening of the screws 18, the first member 26 of the locking means 25, front plate 15 and base 14 will thus provide a rigid unitary structure.

The plate-like member 26 has a first raised part 30 with a key-hole shaped cut-out 31, the purpose of which will become apparent hereinafter, and a second raised part 30' which provides a mounting for a hinge 32.

Hinged to the first member 26, by the hinge 32, is a second plate-like member 35 which has two opposite side parts 36 and a middle part 37, the middle part having an opening 40 and a barrel lock 41 secured thereto.

The opening 40 is rectangular, its width w and length I permitting the plug 11 to be passed therethrough when in a first orientation, i.e. the orientation shown in Figure 1, but as will be described hereinafter with reference to Figure 2, prevents the plug 11 being removed from the socket 13 when engaged with the socket in another orientation.

The lock 41 includes a key-receiving barrel 42 in which a key 43 is shown, and a catch 44 which is rotatable by the key 43 and of corresponding configuration to the key-hole shaped cut out 31 in the first member 26.

Thus the second member 35 can be hinged between an inoperative position as shown in Figure 1, to an operative position shown in Figure 2, when the catch 44 will be received by the key-hole shaped cut out 31 in the first raised part 30 of the first member 26. Thereafter, by rotating the key 43, a projection 44' of the catch 44 will engage behind the periphery of the key-hole shaped cut-out 31 to prevent the second member 35 hinging away from the first member 26.

Referring now particularly to Figure 2, the locking means 25 is shown in an operative position with the second member 35 locked to the first member 26 by the lock 41, and the key 43 has been removed from the barrel 42.

It can be seen that the edges of opening 40 in the second member overlie the plug 11 as the longest side of the rectangular shape thereof is perpendicular to the length of the opening 40 and thus the plug 11 is prevented from being withdrawn from its socket opening 20, whilst the lead 12 extends from the plug 11 through the opening 40.

The side parts 36 of the second member 35 overlie the holes 28 in the first member and thus prevent access being gained to the screws 18 and hence preventing the locking means 25 being removed from the socket 13 as a whole.

It will be appreciated, that the locking means 25 may be used to prevent access being gained to the socket 13. In this event, the second member 35 would be engaged with the first member 26 in an operative position as shown in Figure 2, but without a plug 11 received in the socket 20. Thus it would be impossible to insert the plug 11 into the socket 20 without having a key 43 to unlock the barrel lock 42 and hence disengage the first and second members 26, 35 from their operative condition.

It will be appreciated that many modifications are possible to the locking means 25 described without departing from the scope of the invention.

For example, instead of the second member 35 being permanently connected to the first member 26 by a hinge and hence being hinged from an inoperative to an operative position, if desired the two members 26, 35 may be relatively slidable, whereby a second member may be slid into engagement with guide means of the first member and thereafter locked into an operative condition, or any other means of engaging and locking a second member in an operative position in engagement with the first member may be used. Such an arrangement is shown and described with reference to Figures 3 and 4 hereinafter.

Instead of passing the plug 11 and lead 12 through an opening 40 in the second member 35, the second member 35 andSor the first member 26 may have an aperture such as a slot which permits the lead 12 to extend from the locking means.

If desired, the side parts 36 of the second mem ber 35 could be of other configurations and could for example conceal a greater or lesser proportion of the front plate 15 of the socket 13, although preferably the side parts 36 would overlie the heads of the screws 18 in the holes 28 so as to prevent their unauthorised removal. The screws 18 preferably have conventional heads and the holes 28 are preferably countershrunk, so that the tops of the heads lie flush with the plate 26.

In another embodiment, in place of a barrel lock 41, a combination or other type of lock may be used. In this event, the lock need not have a catch such as shown at 44, which is rotatable to engage the periphery of a correspondingly shaped cut-out 31 in member 26.

In another example, the first member 26 merely provides a U-shaped stirrup which passes through an opening in the second member 35 through which a padlock can pass to lock the two members together.

In place of the first member 26 being secured to the front plate 15 of the socket 13 by the screws 18, the first member 26 may be secured by any other means to the socket. In an alternative arrangement, the first part 26 may be mounted adjacent the socket, for example attached to a mounting surface surrounding the socket by fastenings, and the second member may be engageable with or co-operate with the first member to again overlie the plug 11 and prevent its withdrawal from the socket 13 when the first and second member are locked together in their operative positions.

The second member may in this embodiment comprise a shroud to completely or substantially completely cover the socket 13, or may comprise a locking bar or the like which extends across the plug to prevent the plug being withdrawn from its socket.

Referring now to Figures 3 and 4, an alternative locking means 25' is shown, corresponding parts to the locking means 25 of Figures 1 and 2 being indicated by the same reference numerals, but with a prime sign added.

The locking means 25' is arranged to prevent the withdrawal of the plug 12' (not shown in Figure 3) from a socket 13' which is again a standard telephone socket similar to socket 13 of Figures 1 and 2.

The locking means 25' comprises a first plate-like member 26' and a second plate-like member 35'.

The first member 26' is like member 26 of Figures 1 and 2, engageable with the socket 13' by screws 18' passing through countershrunk holes 28' into openings 19' of the front plate 15' of the socket 13 so that a rigid unitary structure is achieved, although the first member 26' could be engaged with the socket 13 by any other means as required.

The second member 35' has side parts 36' and a middle part 37', the middle part 37' having an aperture comprising a slot 40' which co-operates with an aperture 27' of the first member 26' to trap the lead 12' as seen in Figure 4.

The second member 35' has at each free edge of the side part 36' a first co-operating fonnation 50 which is received by a corresponding channel guide means 51 at each (vertical as seen in Figures 3 and 4) edge of the first member 26'. Thus the second member 35' may be slid relative to the first member 26' from an inoperative position in which the plug 11' may be passed through aperture 27' in first member 26', into engagement with opening 20' of the socket 13', to an operative position shown in Figure 4.

It can be seen that the first member 26' has an aperture 52 in one of the guide means 51, adjacent the upper end thereof, and that the second member 35' carries a spring biased lug 53 adjacent a lower end thereof. As the second member 35' is slid upwardly to permit the plug 11' to be moved from the socket 13', the lug 53 will spring into the aperture 52 to retain the second member 35' to inhibit removal and hence prevent loss of the second member 35'.

Before sliding the second member 35' down to the operative position, it is necessary to disengage lug 53 from the aperture 52 by depressing lug 53 against the force of its spring.

Middle part 37' of the second member 35' carries a barrel lock 41' similar to the lock 41 of Figures 1 and 2, a catch 54 thereof, when the second member 35' is in operative position, being engaged under a projection 54' provided on the first member 26', as shown in Figure 4, upon operation of the lock with a suitable key (not shown).

When the second member 35' is in an operative position, the screws 18' are concealed and so the locking means 25' cannot be removed from engagement with the socket 13'.

Various modifications may be made to the embodiments shown in Figures 3 and 4 without departing from the scope of the invention. For example, the first and second members need not be of the exact configuration shown, but the first and second members may be of alternative configurations. For example, the second member 35' may be provided with a channel guide means to receive a flange or the like provided on the first member 26'.

Instead of the second member 35' being slid downwardly from an inoperative to an operative position, if desired an arrangement may be provided in which the second member 35' slides laterally relative to the first member 26' from the inoperative to the operative position.

Again, instead of the barrel lock 41' a combination lock or another type of lock altogether may be provided.

Although as described, with reference to the drawings, the invention has been applied to a 67mm square telephone socket, the invention could of course be applied to other sizes of telephone socket and to other types of plug and socket assembly altogether. In each case, the second member of the locking means need not overlie the plug as described, but could for example engage a part provided on the plug for example an outwardly extending lip, to prevent its withdrawal from the socket.

For example, the invention could be applied to a conventional 13 amp mains power socket outlet where it is desired to prevent withdrawal of a plug from its socket. In this event, preferably the socket would be unswitched so that the lead to the plug would remain permanently live and hence deter anyone from cutting through the lead in order to interfere with the appliance to which the lead is carrying current.

Claims

1. A locking means for a plug and socket assembly of the kind specified comprising a first member engageable with the socket or mountable adjacent the socket, and a second member engageable with the first member in an operative position with the plug engaged with the socket, to prevent the plug being disengaged from the socket, and a lock (as herein defined) to prevent the first and second members being disengaged from their relative operative positions.

2. A locking means according to claim 1 wherein the socket comprises a housing having a base and a front plate secured together by fasteners such as screws or bolts, the first member of the locking means being engageable with the socket with the same fasteners that secure the front plate to the base.

3. A locking means according to claim 2 wherein the second member of the locking means, at least when engaged with the first member, includes means to prevent access being gained to the fasteners so that the locking means cannot be removed as a whole from engagement with the socket, until the second member is disengaged from its operative position.

4. A locking means according to any one of claims 1 to 3 wherein the first member comprises a plate-like member and the second member also comprises a plate-like member hinged to the first member, the lock, in use, preventing the second member being hinged from its operative position.

5. A locking means according to any one of claims 1 to 4 wherein the first member comprises a plate-like member and the second member com prises a plate-like member, the second member being slidable into an operative position by means of co-operating guide means provided on the first and second members.

6. A locking means according to any one of claims 1 to 5 wherein the first and/or second mem ber has an aperture through which the lead extends, the lead being engaged in the slot as the second member is moved to its operative position.

7. A locking means according to claim 1 wherein the first member is mounted adjacent the socket.

8. A locking means according to claim 7 wherein the first member surrounds the socket and is secured by fastenings to a mounting surface, the second member concealing the fastenings when in its operative position.

9. A locking means according to claim 8 wherein the second member comprises a shroud to partially or completely cover the plug and socket assembly.

10. A locking means according to claim 8 or claim 9 wherein the second member overlies the plug to prevent its disengagement from the socket.

11. A locking means according to claim 8 or claim 9 wherein the second member engages part of the plug to prevent its disengagement from the socket.

12. A locking means as hereinbefore described with reference to and as shown in the accompanying drawings.

13. A telephone, having a body, a lead from the body which terminates in a plug, the plug being, in use, retained in a socket and being prevented from being withdrawn therefrom by a locking means according to any one of the preceding claims, the first and second members of the locking means being in relative operative positions.

14. A telephone substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

15. Any novel feature or novel combination of features disclosed herein andlor as shown in the accompanying drawings.