GB2291280A

GB2291280A - A plug

Info

Publication number: GB2291280A
Application number: GB9413752A
Authority: GB
Inventors: Snorri Erlendsson
Original assignee: Jo Jo A S
Current assignee: Jo Jo A S
Priority date: 1994-07-07
Filing date: 1994-07-07
Publication date: 1996-01-17
Anticipated expiration: 2014-07-07
Also published as: GB9413752D0; GB2291280B

Abstract

The pins 1 of a plug are snap-locked in insulating tubes 3 which project from the base of the plug housing so that the pins can not be released therefrom. As shown, each tube 3 has an internal boss 8 which is a snap fit in a recess 9 in a pin. A shoulder 11 on the pin is held against the end of the tube. The housing cover may be snap-fitted to the base. <IMAGE>

Description

A plug The invention concerns a plug comprising a housing for reception of one or more plug pins protruding from a face on the housing and means for insulating one or more plug pins in the area of the face where the plug pins protrude, said insulation means being formed by one or more tubes.

Such a plug is known from the PCT application WO 94/06177.

In this prior art the plug pins are secured by inserting them into tubes which are formed on a face engaging with the socket with which the plug pins are to mate. Plug pins according to this known structure are provided with tension relief in that the end protruding into the tube is formed with barbs which, upon insertion of the plug pin, retains it in a constriction in the tube. Further, EP-A-1 164 787 discloses a plug which is constructed such that the plug pins are provided with an insulation in the form of tubes which are retained by means of the plug pins and thus form a unit for insertion into a housing for a plug.

The latter structure is rather expensive to manufacture because of necessary working processes in the form of embedding the plug pins in a plastics tube.

Xn general, the above-mentioned types of plugs have the advantage that they provide a great degree of certainty that the live parts cannot be touched when they are connected to a socket.

The object of the invention is to provide a plug which has the same insulation possibility as the above-mentioned known plugs and is additionally constructed such that an extremely sturdy structure can be obtained, while ensuring a favourable cost price. The object is achieved by the plug mentioned in the opening paragraph in that the tube or tubes are formed with snap locking means for reception of the plug pins.

The provision of snap locking means on the tube or tubes provides the advantage over e.g. the first-mentioned structure that the plug pins cannot be released from the tube once they are inserted into it. The use of a fric- tional coupling like in the prior art cannot exclude the possibility that somehow the plug pins can be released from the tube, which is subjected to stresses by pressure from the barbs.

According to a first embodiment of the invention the tube or tubes protrude out of the housing through the face.

This ensures a high degrae of certaintly as far as insula tion of the line parts is concerned.

According to a second embodiment of the invention the tube or tubes protrude into the housing through the face.

This additionally ensures a more stable retention of the plug pins in the tube or tubes.

In a further embodiment the snap locking means are provided on the internal side of the tube or tubes.

This provides the advantage that, if the tube or tubes should fail or break for some reason, then the plug pins cannot be released again after mounting in the tube or tubes.

Finally, it is advantageous according to an embodiment of the invention that the snap locking means are provided on the internal side of the part of the tube or tubes which protrudes into the housing.

This provides the advantage that, if the part of the tube or tubes protruding from the face should break or fail, then the plug pins will nevertheless be stably and fixedly retained in the plug.

To ensure good retention between the tube or tubes and the plug pins, the internal side of the tube or tubes is formed with a boss, while the plug pin is formed with a recess capable of receiving the boss.

The invention will now be explained more fully with reference to the drawing, in which fig. 1 shows a disassembled plug, fig. 2 shows the plug of fig. I in the assembled state, fig. 3 is a top and partially sectional view of the lower half of the plug, fig. 4 is a partially sectional view of the cover for the plug seen into its interior, and fig. 5 shows a plug pin for reception in the plug.

In fig. 1 the numeral 2 designates a base of the plug which is formed with tubes 3, 6 for reception of plug pins l. As will be seen, the tubes are formed in.a face 19 which, when coupled with a socket (not shown), engages a face on the socket. Further, fig. 1 shows a fuse 19 which can be positioned in a holder in the base of the plug and be connected to a connector 5. A8 will be seen from fig.

3, the tubes 3 are formed with a part 17 protruding outwardly from the face 19 and a part 18 protruding inwardly from the face 19. Further, the inner side of the tube 3 is provided with a boss 8, whose function will described more fully below. Fig. 3 additionally shows tension relief means 14 at the end of the plug where the wire is introduced, and also shows snap locking means 15 adapted to receive, cf. fig. 4, snap locking means from the cover 4 by means of additional snap locking means 16 provided inside the cover 4.

Fig. 5 shows a plug pin generally designated 1. The plug pin has an outer part 20 which is formed with an edge 12 at one end and is formed with an engagement face 11 at the other end which merges into a further extension. The innermost end of the plug is provided with a recess 9 which is adapted to cooperate with the boss 8, cf. fig. 3, on the base of the plug. Fig. 5 additionally shows that a wire 10 may be secured in a hole on the plug pin 1.

It will now be explained how the plug is used. The plug pins 1 are inserted into the tube from the outer side of the tube so that the recess 9 on the plug pin engages the boss 8 on the internal side of the tube 3, and the engage ment face 11 on the plug pin engages the outermost face 13 on the tube 3. When the plug pins are secured on the base of the plug, they form a releasable fit in the base. A wire 10 can now be connected to the plug pins 1, and then the cover 8 is mounted by the snap locking means 16, 15.

As explained above, the foregoing description illustrates a specific embodiment of the plug according to the invention, but it will be appreciated that modifications are conceivable within the scope of the patent claims, such as embodiments having more or fewer than three plug pins.

Claims

Patent Claims.

1. A plug comprising a housing for reception of one or more plug pins (1) protruding from a face (19) on the housing and means (3) for insulating one or more plug pins in the area at the face (19) where the plug pins (1) protrude, said insulation means being formed by one or more tubes (3) protruding from the face (19), c h a r a c t e r S z e d in that the tube or tubes are formed with snap locking means (8) for reception of the plug pins (1).

2. A plug according to claim 1, c h a r a c t e r i z e d in that the tube or tubes (3) protrude out of the housing through the face (19).

3. A plug according to claim 1, c h a r a c t e r i z e d in that the tube or tubes (3) protrude into the housing through the face (19).

4. A plug according to claims 1-3, c h a r a c z e r i z e d in that the snap locking means (8) are formed on the internal side of the tube or tubes.

5. A plug according to claim 4, c ha r a c t e r i z e d in that the snap locking means are formed on the internal side of the part of the tube or tubes which protrudes into the housing.

6. A plug according to claims 1-5, c h a r a c t e r i z B d in that the snap locking means (8, 9) are formed by a boss (8) on the internal side of the tube or tubes (3) and by a recess (9) on the plug pin.

7. A plug substantially as described herein with reference to the description and the claims.