GB2134337A

GB2134337A - Releasable cover for electrical plug

Info

Publication number: GB2134337A
Application number: GB08401692A
Authority: GB
Inventors: Stanley Oshry
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-01-25
Filing date: 1984-01-23
Publication date: 1984-08-08
Also published as: GB2134337B; GB8401692D0

Abstract

A cover (2) of multi-pin electrical plug is slideably engageable onto the base plate (6) of the plug by means of co-operating tongue and groove formations and is releasably retained in a closed position by means of a releasable catch (10) and a cooperating stop formation (recess 13). The catch (10) is mounted on a resilient tongue (11) and may be moved manually against the resilience of the tongue for release. Contacts of the plug pins may be formed with thumb screws (16) having cross formations for receiving a screwdriver. <IMAGE>

Description

SPECIFICATION A multi-pin electrical plug This invention relates to a multi-pin electrical plug of the general type used for insertion into wall sockets and the like in order to supply power, by a cable, to electrical apparatus.

Such electrical plugs have been made in numerous different forms, most of which have involved the use of screws of a type which necessitate the use of a screw driver in order to open them and connect electrical conductors thereto.

A recently marketed plug has a cover which hinges at its rear end and is a snap fit onto the plug body by way of interengaging and co-operating latch formations extending into the centre of the body from each of the lid and body. Such interengaging formations must, when the plug body is to be opened, be released with the aid of a screw driver which, at least to a large extent, obviates the advantage to be obtained.

It is the object of this invention to provide an electrical plug assembly of the basic type outlined above and wherein no screw driver or other implement is necessary in order to open the plug. Whilst not being related to this invention, it is also possible to render the terminals associated with the electrical pin such that they can be tightened without the aid of any external implements such as screw drivers, for example.

In accordance with this invention, there is provided a multi-pin electrical plug comprising a base having parallel, electrically conductive pins extending therefrom, terminals associated with such pins on the opposite side of the base, and a cover for said terminal side of the base, the base and cover being provided with co-operating tongue and groove formations extending transverse to the axis of the pins and adapted to co-operate to allow the cover to be slid onto the base, and a manually releasable, integral catch and co-operating stop formation adapted to interengage in the closed condition of the cover relative to the base.

Further features of the invention provide for the base to have two opposite, substantially parallel edges which define tonges co-operating with grooves provided in side walls associated with the cover; for the plug to be a three pin plug; for the catch formation to be integral with the base and to extend transverse to the direction of movement of the cover during installation on the base; for the said catch to be positions at or near the leading end of the base relative to the cover; and for the co-operating stop formation to be a recess formed in the edge of a side wall of the cover.

It is to be understood that, whilst the catch is described as being integral with the base or cover, the term integral is, in this specification, to be interpreted as including arrangements wherein a catch is permanently attached to the base or cover after separate manufacture thereof by solvent or heat welding or untra-sonic welding or any other suitable permanent means of attachment.

It will be understood that as the tongues and grooves extend in a direction transverse to the axis of the plug there is no possibility of the cover coming off the base as a result of a pulling action to remove the plug from a socket. This is highly advantageous when compared with a number of prior art plug assemblies.

In order that the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings in which: Figure 1 illustrates, in longitudinal section a three pin electrical plug base and cover therefor in an exploded condition, Figure 2 is an isometric view illustrating the base in top isometric view and the cover in underneath isometric view in an exploded condition, and, Figure 3 is an isometric view similar to Figure 2, but of a modified embodiment of the invention.

In this embodiment of the invention, an electrical plug comprises a base (1) and a cover (2) therefor.

The base (1) is a substantially flat base having an end wall (3) at one end thereof with a recess (4) therein to accommodate a cable entering the plug. Integral cable grip members (5) are formed adjacent the end wall of the base.

The base is rectangular in plan view and the edges (6) thereof are adapted to co-operate with grooves (7) in side walls (8) of the cover (2). The edges (6) thus define tongues for co-operation with the grooves (7).

The base supports the normal arrangement of three electrically conductive pins (9) extending therefrom with their axis at right angles to the plane of the base.

It will be appreciated that the edges (6) of the rectangular base can be slid into the grooves (7) of the cover in a direction at right angles to the axis of the pins and starting from a position of the nature illustrated in Figure 1.

In order to retain the base in an operative position relative to the cover a catch member (10) supported by an inverted U-shaped support (11) integral with the base is provided at the leading end (12) on one side of the base. This catch member extends laterally outwardly from the side edge of the base and cooperates, in closed condition, with a recess (13) provided the lower edge of the side wall (8) of the cover. The catch member (10) is arranged such that it is manually releasable and the resilience of the material from which the base is made maintains it in its operative cobperating position relative to the recess (13). The front end wall (14) of the cover is also provided with a groove (15) to cooperate with the leading end (12) of the base.In this manner three complete side walls of the cover cooperate with edges of the base to form a secure connection between the two. In the completely closed condition the catch member (10) snaps into cooperating relationship with the recess (13) when the cover is slid onto the base. The catch member in this case, therefore, moves predominantly in a direction transverse to the plane of the base.

Depending on design requirements, it may be necessary to flex the catch member in order to introduce the base member into the grooves (7) in the cover but, it is also within the scope of this invention, that a ramp (not illustrated) be provided for automatically flexing the catch to a position in which it slides along the lower edge of the associated side wall until it snaps into cooperating relationship with the recess (13) therein. Release of the cover from the base is simply achieved by manually flexing the catch member (10) from the recess and sliding the cover off the base. It will be understood that this can, to all intents and purposes, only be achieved when the plug is disengaged from a socket.

It will be understood that absolutely no outside tools or the like are necessary in order to either locate a cover as above described on its associated base or remove it therefrom.

In order to render the remainder of the plug such that no tools are required the terminals, generally indicated by numeral 16, are preferably made as described in our issue South African Patent Number 82/4936 entitled "Terminal Connectors for Electrical Plugs". Such terminal connectors require no outside tools in order to secure them in their operative positions and, if required, cross-shaped slots (18) can be embodied in the electrically insulated thumb screw surface.

Such slots can be engaged by a protrusion (19) on the cover, which is made to cooperate therewith, in order to assist in the mechanical rotation of the thumb screws if a finger tightness proves to be insufficient.

It will be understood that numerous variations may be made to the above described embodiment of the invention without departing from the scope hereof. In particular the nature of the catch can be varied widely so long as it remains manually releasable and automatically moves into cooperating relationship with its associated stop when the cover is fully positioned on the base. In fact, the trailing ends of the side walls could be provided with laterally outwardly extending protrusions which define the catch members and which cooperate, in the fully closed position, with cooperating recesses provided in the edge of the base. Numerous other forms of catch and stop arrangements are possible so long as they are integral with the base and cover, as defined above.

One variation of catch member and co-operating stop formation are illustrated in Figure 3 in which the catch member 20 is co-planar with the base 21 of the plug and located towards the leading end of a side edge 22 of the base in the above described type of arrangement.

The catch member stands proud of the edge member 22 and is made integral with the base through an inverted U-shaped support 23 basically as above described.

However, in this case, the leading end of the catch 20 is bevelled (as indicated by numeral 24) to ensure automatic retraction of the catch member during installation of the cover on the base and with the catch member sliding in the groove 25 accommodating the edge 22 of the plug. Thus, during installation, the U-shaped support is deformed against its natural spring bias-so that the outer edge 26 of the catch member is substantially co-linear with the edge 22.

The cover is provided with a slot 27 through its side wall and communicating with the groove 25 so that the catch member can snap into the slot 27 once the cover has been fully installed on the base.

The end 28 of the slot nearer the entry end of the groove 25 thus cooperates with the trailing end 29 of the catch to prevent the cover from being removed from the base.

A formation (not shown) which projects downwardly from the catch member can be manipulated manually, from the underside of the pipe, in order to withdraw the catch member from the slot against the bias of the support in order to create a sliding action of the cover to remove it from the base. Once the sliding action has commenced the catch member can be released.

It will be understood that the bevelled leading end 24 of the catch member 20 will automatically cause the catch member to move against its bias during reintroduction of the cover onto the base and the catch member will automatically snap into its operative position in the slot 27 once the cover is fully installed.

In this case, accordingly, the catch member moves in substantially the same plane as the base as opposed to the abovedescribed embodiment of the invention where it moved transverse to the base.

The invention provides an extremely simple yet highly effective means of associating a cover with a base of an electrical plug without necessitating the use of any tools to release the cover from the base as and when required.

Claims

1. A multi-pin electrical plug comprising a base having parallel, electrically conductive pins extending therefrom, terminals associated with such pins on the opposite side of the base, and a cover for said terminal side of the base, the base and cover being provided with cooperating tongue and groove formations extending transverse to the axis of the pins and adapted to cooperate to allow the cover to be slid onto the base, and a manually releasable, integral catch and cooperating stop formation adapted to interengage in the closed condition of the cover relative to the base.

2. A multi-pin electrical plug according to Claim 1 wherein the base has two opposite, substantially parallel edges which define tongues cooperating with grooves provided in sidewalls associated with the cover.

3. A multi-pin electrical plug according either Claim 1 or Claim 2 wherein the catch formation is integral with the base and extends transverse to the direction of movement of the cover during installation on the base.

4. A multi-pin electrical plug according to Claim 3 wherein the catch is permanently attached to the base by solvent or heat welding or ultra-sonic welding or any other suitable permanent means of attachment.

5. A multi-pin electrical plug according to any one of the preceding claims wherein the catch is positioned at or near the leading end of the base relative to the cover.

6. A multi-pin electrical plug according to any one of the preceding claims wherein the cooperating stop formation is a recess formed in the edge of a side wall of the cover.

7. A multi-pin electrical plug according to any one of the preceding claims wherein a ramp is provided for automatically flexing the catch to a position in which it slides along the lower edge of the associated side wall unitl it snaps into cooperating relationship with the recess therein.

8. An electrical plug according to any one of the preceding claims wherein three pins are provided.

9. A multi-pin electrical plug according to any one of the preceding claims wherein a recess is provided in an end wall of the base to accommodate a cable entering the plug.

10. A multi-pin electrical plug according to any one of the preceding claims wherein cable grip members are formed adjacent to the end wall of the base.

11. A multi-pin electrical plug according to any one of the preceding claims wherein the terminals require no outside tools in order to secure them in their operative positions.

12. A multi-pin electrical plug according to any one of the preceding claims wherein the cover is provided with protrusions which are adapted to cooperate with slots embodied in electrically insulated thumb screw surfaces of the terminal connections.

13. A multi-pin electrical plug according to Claim 1 and substantially as described in the accompanying description with reference to the accompanying drawings.

14. An electrical plug comprising a base having pins extending therefrom, and a cover, the base and cover being provided with cooperating formations adapted to cooperate to allow cover and base to interengage by sliding action, and a manually releasable locking means having components on the base and cover adapted to engage in the closed condition of the cover relative to the base.