GB2032711A - Electrical plug - Google Patents

Abstract

An electrical plug, particularly for use in a motor vehicle, has a generally cylindrical body composed of two half-shells (1,2) of insulating material within which are mounted the electrical contacts (3,4) for engagement with the co-acting contacts of an associated socket. The conductor leads of a cable are secured in the plug body by tong-like or lever-like terminals (6,7) to establish electrical contact with the plug contacts (3,4). The conductor leads can be secured without opening the body by displacing an internal clamping member (8) attached to an external operating member (9). An externally operable cable clamp (10) is also provided on the plug. The assembly of the components of the plug achieved without the use of detachable securing elements such as screws. <IMAGE>

Description

SPECIFICATION Electrical plug This invention relates to an electrical plug, for attachment to the conductor leads of an electrical cable, in particular but not necessarily exclusive to a plug suitable for known motor vehicle plug sockets.

A known form of electrical plug for use in motor vehicles comprises a body that is composed of half-shell members of insulating material, with contacts in this plug body, and also with a cable grip for relieving the inserted ends of the conductor leads of tension, clamping screws being used for securing the conductor leads to the plug contacts, and a further screw holding together the two halfshell members of the plug being employed to clamp the inserted cable in place through a gripping effect in order to provide the relief from tension stresses.

A plug of this kind comprises a number of parts, and these add to the costs of production, particularly assembly costs. If, as is usual, the plug is sold without an attached cable, for the purpose of installing the cable, the plug must be dis-assembled and re-assembled so that this cable and the means for providing relief from tension stresses can be attached.

According to the present invention, there is provided an electrical plug for attachment to the conductor leads of an electrical cable, comprising electrical contacts in a body of insulating material, wherein the conductor leads are arranged to be secured in the plug body by tong-like or lever-like terminals for establishing connection with said electrical contacts.

Preferably, it is arranged that said terminals face one another and have between them a clamping member which can be operated from outside the plug body to cause them to engage conductor leads inserted into the body. If the plug body comprises two halfshells, it may further be arranged that the clamping member is, together with an external operating member therefor, mounted in one of said half-shells.

An externally operable cable grip can also be provided in a plug according to the invention, said cable grip comprising, for example, an eccentric member pivotally mounted on the plug body.

An electrical plug according to the invention is illustrated by way of example in the accompanying drawings, in which: Figure 1 shows, in partial cross section, a half-shell of the plug body with electrical contacts inserted, Figure 2 is a cross-sectional view of the plug, showing both half-shells, this cross-section being taken in a plane perpendicular to that of Fig. 1.

Figures 3 and 4 are end elevations, of the plug as viewed from the cable end and the contact end respectively, and, Figure 5 shows a detail of one of the body half-shells.

The plug shown in the illustrated embodiment is intended for use in a motor vehicle, and is for example suitable for connecting ancillary equipment, such as manually-held vacuum cleaners or the like, to a motor vehicle plug socket (not shown) which is usually constituted as an elongate socket with a circular cross-section. This form of elongate plug socket has a central connecting contact at the bottom of the socket, and also a second contact which consists of a hollow cylindrical metal sleeve to co-operate with a contact correspondingly provided at the side of the plug.

The plug body proper consists of insulating material and is composed of two half-shells 1 and 2. Inserted in suitably constructed receiving portions of the plug body are a metal contact plate 3 for the central contact, and a metal contact plate 4 for the lateral contact.

The central contact is fixed to the half-shell 1 by means of a rivet 5.

Further, two terminals 6 and 7 are inserted in the plug body and, like the metal contact plates 3 and 4, may consist of metal strips.

The contact 4 and its associated terminal 6 may also be formed as a unit constituted by an elongate metal strip, which is simply folded over at one end. The terminals 6 and 7 lie opposite one another and between them is a clamping member or stud 8 which can be operated from outside the plug body. This clamping member 8 is provided with an elongate operating member 9 in the form of a finger grip and together with this member 9 is mounted rotatably in the half-shell 1. Also in the half-shell 2 is a bearing socket for receiving and supporting a projection of the clamping member 8.

When the operating member 9 points away from the plug body at an angle of approximately 90 , the clamping member 8 is in the position illustrated in Fig. 1 in which the terminals 6 and 7 are in their fully-open positions. After one of the two conductor leads of a two-core cable has been inserted between the end of a contact 4 and the terminal 6, and the other conductor lead has been inserted between the end of contact 3 and terminal 7, the operating member 9 is pivoted into a position in which it lies exactly parallel to the half-shell 1 and is disposed within the peripheral contour or envelope of said half-shell.The clamping member 8 will also have been turned through about 90= and will then urge the terminals 6 and 7 onto the ends of the contacts 3 and 4, as a result of which the conductor leads are secured to make electrical contact therewith.

The operating member 9 is formed with a slot 9a which resembles the slot in a screw head and which is particularly clearly shown in Fig. 5; this slot 9a can facilitate the control of the operating member 9. As Fig. 5 also shows, a small projection 9b is present on the member 9 and engages in a recess, of complementary shape, in the half shell 1, and serves to securely locate the member 9 in the end position in which the terminals 6 and 7 grip the conductor leads in tong-like or leverlike manner.

The two half-shells 1 and 2, which are made of insulating material, are connected together without the use of screws. The metal contact strip 3 ends in the plate-shaped part 3a, which is secured to the half-shell 1 by a rivet 5. Rivet 5 can also serve as an electrical contact. A projection or appendage 2 a of the second half-shell 2 is introduced into a semicircular opening in the plate-shaped part 3a, and is suitably shaped for this purpose. At the other end of the plug a part 1 a of the halfshell 1 is extended (raised), and engages with a shoulder behind the other half-shell 2. The projection 1 a is provided with an oblique starting or run-in surface, and its wall thickness is chosen such that it can give resiliently and snap-fit behind the hemispherical member 2.This mutually-interlocking engagement can be further assisted by providing for a slight give of the plate shaped part 3a.

The projection 1 a of the half-shell 1 further serves the purpose of carrying an eccentric 10 which is used as a cable clamp for relieving the lead connections of tension stresses that may be applied to the cable. The eccentric 10 is rotatably mounted on a collar stud-shaped extension, i.e. of pin-like shape with an enlarged end, which is secured in a keyhole shaped opening in the extension 1 a. The elongate hole comprises, in a known manner, a larger opening through which the extension of the eccentric can pass, and also a narrower portion in which the shank of said extension is retained in the manner of a bayonet-type joint.

The eccentric 10 can be turned by means of a slot (see Fig. 3) which resembles the slot of a screwhead. This eccentric 10 has, at its periphery, rib-like projections which press on the inserted cable, which is thus gripped between the eccentric 10 and an edge 1 b of the halfshell 1.

For the user of the plug, there is the advantage that he only needs to insert the conductor leads of the cable into the plug, whereupon these leads are securely gripped against the internal contacts, as a result of pivoting the operating member 9a, by means of the clamping member 8. A simple turm of the eccentric 10 then firmly secures the cable so that the lead connections will be free of any tension stresses on the cable. There is no need for opening the plug body or for the manipulation of screws or like detachable securing means, which can easily become lost.

Claims (14)

1. Electrical plug or attachment to the conductor leads of an electrical cable, comprising electrical contacts in a body of insulating material, wherein the conductor leads are arranged to be secured in the plug body by tong-like or lever-like terminals for establishing connection with said electrical contacts.

2. Plug according to claim 1 wherein said - terminals are resilient.

3. Plug according to claim 1 or claim 2 wherein said terminals and said electrical contacts are in the form of metal strips.

4. Plug according to any one of claims 1 to 3 wherein said terminals face one another and have between them a clamping member which can be operated from outside the plug body to cause them to engage conductor leads inserted into the body.

5. Plug according to any one of the preceding claims wherein the body comprises two half-shells.

6. A plug according to claim 4 together with claim 5 wherein the clamping member is, together with an external operating member therefor, mounted in one of said halfshells.

7. Plug according to claim 5 or claim 6 wherein the two half-shells are interconnected by a plate-shaped part of one of the contact members.

8. Plug according to claim 7 wherein the plate-shaped part is fixed to one of the halfshells by riveting and the second half-shell is inserted in an opening of the plate-shaped part.

9. Plug according to any one of claims 5 to 8 wherein the two half-shells are held together through snap-engagement means.

10. Plug according to any one of the preceding claims provided with a cable grip to protect the secured ends of the leads from cable tension.

11. Plug according to claim 10 wherein the cable grip comprises an eccentric member.

1 2. Plug according to claim 11 wherein the eccentric member has ribs ot the like on a peripheral surface arranged to engage the cable.

1 3. Plug according to claim 11 or claim 1 2 wherein the eccentric is rotatably fixed in a key-hole shaped opening in the plug body.

14. Electrical plug constructed and arranged for use and substantially as described herein with reference to the accompanying drawings.