GB2222034A - Preventing removal of plug from socket - Google Patents

Abstract

An electrical accessory assembly comprises a plug and socket 10, 12 for mechanical and electrical engagement, wherein an abutment plate 20 overfits a face plate 14 of the socket outlet 12F being retained by clips 20P engaging the periphery 14E of plate 14. <IMAGE>

Description

Title: Electrical Accessories DESCRIPTION This invention relates to electrical accessories, particularly to cooperating plug-and-socket type connection devices having mutual mechanical engagement additional to making mutual electrical connection at respective contacts thereof, i.e. not relying solely on gripping between contacts of the devices but achieved during relative movement of the devices effective to achieve both of mutual mechanical engagement and mutual electrical connections.

According to this invention there is provided associated or associatable with the socket device abutment means serving to obstruct movement of a mating plug device out of its electrical connection and mechanical engagement with the socket device.

We make electrical connection devices, presently marketed using the trade mark KLIK, wherein contact pins projecting from one face of a plug device enter apertures in one face of a socket device and electrical contact connection is made only after rectilinear relative movement of the devices at their said one faces then confronting, which movement also secures mutual mechanical engagement preventing separation of the devices without reversal of the rectilinear relative movement. In applying this invention to such connection devices, said abutment means will be operative to obstruct that reverse rectilinear relative movement.

Suitable and advantageously simple abutment means comprises a part securable to and detachable from the socket device after full mating thereto of a plug device. A suitable part will engage an end of the plug device so as to obstruct its movement, or possibly engage an indentation into or projection from some other part of the plug device, typically a side thereof but perhaps even the other end of the plug by suitable cooperating formations thereat and of the abutment part. As an alternative to such a securable and detachable part, a part of or captive to the socket device may be employed, for example of a spring-loaded tooth type, say that requires depression to disable its obstruction of the plug device, perhaps use of a tool for such depression or retraction, maybe even for its extension into obstructing position.

At least where, as is often the case, basic socket units are associated with face plates of outlet electrical accessories, the abutment means may be associated or associatable directly with such face plate. Moreover, a simple securable and detachable abutment part could be so secured using normally provided holes for screw-mounting the plate to an accessory base or mounting box, or, as will be specifically described and illustrated, with a clip-on action -requiring a tool to remove. At least aesthetically, it is then preferred, though not essential, for the abutment part to be as a plate overfitting the face plate and apertured to fit round the mated plug device.

We have located a likely but as yet unsatisfied demand for provisions of this invention at least ' in applications of four-pin versions of our KLIK system to emergency lighting units where it is undesirable for a connection to be and remain unmade, at least unintentionally, in view of battery charging requirements. Test of such a unit is, however, quite easy by disabling the abutment means, say detachment from an accessory base plate and moving back over electric cable or cable for the plug device.

Specific implementation of embodiment of this invention will now be described, by way of example with reference to the accompanying drawing in which: Figure 1A and B show a plug in bottom plan and end views; Figure 2 shows an accessory plate including a socket for the plug of Figure 1; Figure 3 shows a plug locking plate in top and bottom plan, and sectional views C-C and D-D, subscripted A-D, respectively; Figure 4 is an exploded view of a ceiling fitting; and Figure 5 is a fragmental section showing preferred location/securement of the locking plate of Figure 3 to the socket plate of Figure 2.

In the drawing, the illustrated plug 10 is of the 4-pin type known as KLIK AX, which is particularly suited to applications where an additional live connection is required, for example in emergency lighting for assuring battery charging and in dimmer controlled fluorescent lighting for starting purposes.

The socket unit 12 of the accessory plate 14 is of a corresponding type, and the plate 14 is shown as being of a circular type with customary fixing holes 16A, 16B for an accessory base, see 18 in Figure 4, or an outlet box.

The locking plate 20 is shown with an aperture 22 generally matching the exterior of the plug 10 where it meets and mates with the socket unit 12. The plate 20 could have holes at 24A, 24B to register with those 16A, 16B of the socket plate 14 in screw-securing the locking plate 20 thereto. A downturned strengthening rim is shown at 22R about the aperture 22. If desired, interior projections could be mounted about securement holes 24A, 24B to locate in screw-head accommodation of the holes 16A, 16B of the accessory plate 14.

In the embodiment illustrated, the accessory plate 14 has an undercut peripheral edge 14E, normally to be snap-fitted by a cover, and the locking plate 20 is shown with inner projections 20P to snap-fit therewith.

When secured, the edge 22A of the aperture 22 of the locking plate 20 will serve as an abutment preventing sliding of the plug 10 in the direction of the arrow A in order to achieve electrical disconnection and permit disengagement of the plug from the socket unit by clearance of free limbs of its L-shaped pins 10L from under the socket unit face 12F and of ends of its T-shaped earth pin and locating projection 10T and lOP.

In use, the locking plate 20 has the plug 10 threaded through the aperture 22 and is loose on cable or cord to the plug 10. The plug is fitted into the socket unit 12 and slid rectilinearly into electrical connection. Then, the locking plate 20 slid back over the plug and secured in place on the accessory plate 14. Retrofitting of the locking plate 20 into existing accessories maybe facilitated after removal of a said cover if the locking plate 20 has a corresponding exterior undercut (see Figure 5) for the cover to refit.

A plug-and-socket type ceiling fitting is shown in Figure 4 exploded, see base or box 18 for a KLIK socket plate 14 and fixing screws, also (at 10) KLIK plug with internal sheath grip cover and fixing screw, and a cover, further with the position of a locking plate (20) indicated.

It will be appreciated that provision of a locking plate 20 with an aperture 22 matching the plug 20 is as matter of preference, and that any other abutment provision may be made for example secured to engage stepping lOS of the plug 10, or just to engage its end in place of the edge 22A of the aperture 22, or to engage in recessing of a side of the plug 10, or to abut projection from such side. Moreover, an extensible and retractable tooth provision for the accessory plate 14 could be employed, whether requiring positive action for both extension and retraction and or just for retracation, then preferably requiring a tool so to do.

Claims (13)

1. An electrical accessory assembly comprising cooperating plug and socket devices and wherein there is provided associated or associatable with the socket device abutment means serving to obstruct movement of the mating plug device out of its electrical connection and mechanical engagement with the socket device.

2. An assembly as claimed in claim 1 in which the plug and socket devices have mutual mechanical engagement additional to making mutual electrical connection at respective contacts thereof.

3. An assembly as claimed in claim 2 in which contact pins projecting from one face of the plug device enter apertures in one face of the socket device and electrical connection is made only after rectilinear relative movement of the devices at their said one faces then confronting, which movement also secures mutual mechanical engagement preventing separation of the devices without reversal of the rectilinear relative movement and wherein the abutment means is operative to obstruct that reverse rectilinear relative movement.

4. An assembly as claimed in any one of claims 1 to 3 in which the abutment means comprises a part securable to and detachable from the socket device after full mating thereto of a plug device.

5. An assembly as claimed in any one of claims 1 to 4 in which a suitable abutment means part will engage an end of the plug device so as to obstruct its movement or engage on indention into or projection from some other part of the plug device.

6. An assembly as claimed in claim 5 in which the indention or projection is a,t a side of the plug or at its other end by suitable cooperating formations thereat and of the abutment parts.

7. An assembly as claimed in any one of claims l to 3 in which the abutment means comprises a part of or captive to the socket device and/or plug device.

8. An assembly as claimed in claim 7 in which the part is of spring-loaded tooth type that requires depression to disable mutual obstruction of the two devices.

9. An assembly as claimed in any one of the preceeding claims in which the socket is associated with a face plate of an outlet electrical accessory and the abutment means is associated or associatable directly with such face plate.

10. An assembly as claimed in claim 9 in which the abutment means is secured using normally provided holes for screw-mounting the plate to an accessory base or mounting box or with a clip-on action preferably requiring a tool to remove.

11. An assembly as claimed in claim 9 or 10 in which the abutment means is a plate overfitting the face plate and apertured to fit round the mated plug device.

12. An assembly constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. An abutment means serving to obstruct movement of mating plug and socket devices out of their electrical and mechanical engagement constructed and arranged substntially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 3A to 3D.