GB2193051A - A coding element for a multi- terminal electrical connector - Google Patents

Abstract

Coding of connectors (1, 2) to prevent interconnection of incompatible types is achieved in a readily changeable manner by insertion of a coding element, in the form of a elongate body (13), into at least one of the contact positions (B). If the opposing pin or socket chamber (3, 7, 12, 15) is empty, interconnection of the plugs (1, 2) is possible by plugging of pins 4 into sockets 8 at other contact positions A (Figs. 1, 2), whereas if the opposing chamber is not empty, and contains a terminal (eg 4, Fig. 4) interconnection is not possible. The coding element may replace a pin (as shown), or fill a socket connector (Fig. 5 not shown) to prevent a pin entering the socket. <IMAGE>

Description

SPECIFICATION A coding element for a multi-polar electrical plug-in connector This invention relates to a coding element for a multi-polar electrical plug-in connector of the type wherein contact pins and/or contact sockets are retained within bores formed at defined contact positions.

Coding elements serve to prevent unintentional plug-in combinations of incompatible connectors, e.g. plugs of the same type.

In one known arrangement for multi-pole rectangular plugs, a respective coding pin is arranged on each contact carrier or plug, i.e.

on each side of the contact plane. Each pin has a central region of hexagonal cross-section and, at its end fitting into its plug, a reduced diameter region with an external thread. At its other end each pin is flattened or cut away to the centre of its cross-section over an adequate length in the direction of the pin axis. For reception of the coding pins, the contact carriers or plugs have through-holes which are widened hexagonally at the side of the contact plane. The coding pins are inserted with the hexagonal regions fitting into these widenings and the threaded regions projecting through the holes to be secured on the reverse side of the contact carriers or plugs by nuts. As a result of the hexagonal shape of the central region, each coding pin can be mounted in six different positions as regards the angular disposition of the relevant flattening.Such a plug-in connection can only be put together when the flattened coding pins of the one plug and the relevant ends of the counterplug supplement one another to form the original full cross-section as a result of correct angular positioning. Such plugs already have a specific coding when delivered from the manufacturer. The appropriate operations for changing the coding are very labour-intensive since the relevant coding elements which have already been mounted have to be dismantled and reinstalled in a new position.

In the case of multi-polar round plugs, the coding is usally effected by at least two radial projections which are present on the one plug and which, during the plug-in procedure, are guided in the plug-in direction in appropriately arranged grooves formed in the surface of the other plug. By providing different arrangements of projections and complementary grooves, a large number of different codings can be obtained. However, the store-keeping this necessitates to stock such a wide range is disadvantageous. Moreover, in the case of these plugs, subsequent changing of the coding is not possible.

Accordingly, the object of the invention is to develop a means of coding which is very simple, is applicable to both rectangular and round plugs, is readily changeable, and is effected without appreciable additional expenditure.

With this object in view, the invention provides a multi-polar electrical plug-in connector formed with bores at defined contact positions, and contact pins and/or contact sockets retained within the bores at specific contact positions by means of securing elements, characterised in that a coding element in the form of an elongate body is inserted into the bore at at least one contact position.

The advantage of using such a coding element is that a coding can be produced very rapidly with conventional tools and the storekeeping of the relevant plug-in connectors is considerably simplified.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a fragmentary cross-section illustrating a plug-in connection achieved between connectors having a coding element in accordance with a first embodiment of the invention; Fig. 2 is a view similar to Fig. 1 illustrating a connector combination which cannot be plugged in; Fig. 3 is a fragmentary cross-section illustrating a plug-in connection achieved between connectors having a coding element in accordance with a second embodiment of the invention; Fig. 4 is a view similar to Fig. 3 illustrating a connector combination which cannot be plugged in; Fig. 5 is a fragmentary cross-section illustrating a plug-in connection achieved between connectors having a coding element in accordance with a third embodiment of the invention; and Fig. 6 corresponds to Fig. 5 but shows a combination of connectors which cannot be plugged in.

Figure 1 shows fragmentarily a plug-in connection consisting of a pin plug 1 and a socket plug 2. Of the large number of aligned contact positions which may be provided, the fragmentary view shows only two, namely those designated A and B. Each contact position consists of a chamber or bore in the pin plug 1 which is in alignment with a chamber or bore of the counter-plug or socket plug 2.

A contact pin 4 is inserted into the pin chamber 3 and is held by a securing element 5 which engages behind a collar 6 present on the pin 4. Disposed in the chamber 7 of the socket plug 2 is a socket 8 having a collar 9 which co-operates with a further securing element 5. The pin chamber 3 and the socket chamber 7 have, in their mouth regions, respective constrictions 10 and 11. The contact position B is modified compared to A by having the constrictions 10 and 11 drilled out or otherwise removed to form a coding position.

The remaining dimensions of the chambers 3 and 7 remain the same as in A. Inserted into the coding chamber 12, which has been created from the chamber 3 is a coding element 13 having a collar 14. The corresponding coding chamber 15, created from the chamber 7 of the socket plug 2, is empty.

The pin plug 1 can be combined with the socket plug 2, because the coding chamber 15 is not occupied by a coding element, and this enables the projecting end of the element 13 to be inserted therein as the plugs 1 and 2 are brought together.

Obviously, if several coding positions are provided on a specific type of plug a large number of coded plug combinations can be produced. In this respect it will be noted that at least one coding element is always provided per coding position.

Figure 2 shows the pin plug 1 exactly as in Fig. 1 and arranged opposite to this a socket plug 16 of the same type as in Fig. 1. However, since the coding position B of this latter plug 16 also contains a coding element 13, this combination cannot be fitted together. In other words plugging of the pin into its complementary socket is prevented by the presence of the coding element in the socket plug 16.

Figure 3 shows contact position C of a pin plug 17 and of a socket plug 18 in the assembled state. In this instance the pin chamber 3 is empty, whilst a coding element 19 having a collar 20 is inserted into the chamber 7 of the socket plug 18. As the coding element 19 is formed with reduced diameter end regions, it does not require a special (drilledout) coding chamber and, assuming similarity of type, it can be inserted into any socket chamber.

Figure 4 shows the socket plug 1 8 exactly as in Fig. 3, and standing opposite to this a pin plug 21 of the same type as in Fig. 3.

However, since the contact position C of this plug 21 is occupied by a contact pin 4, this combination cannot be fitted together. In other words, insertion of the pin 4 into the complementary socket chamber 7 isprevented by the presence of the coding element 1 9 in said chamber 7.

The coding element 19 has a reduced diameter region 22 at each end, and, at the end adjacent the contact plane of the relevant plug, this region 22 projects into the constriction 11. In this way, the coding of a plug is perceptible by a visual check.

All the aforesaid coding elements can in principle be installed and removed in similar manner to the corresponding contact elements, i.e. the pins and sockets, by using the same tools as are intended for that purpose.

In this respect, the securing elements 5 present in both the pin and socket chambers 3, 7 are also used for -fixing the coding elements 13, 19. All the aforedescribed coding elements have a preferred shape which is symmetrical with respect to the collar 14, 20. In this way, installation of the coding elements is facilitated, in that checking for correct orientation of the elements is not needed. In this respect, it will be understood from Fig. 3 that as a result of the two reduced diameter regions 22 the element 19 will always be correctly installed, whichever end thereof is inserted first into the chamber 7.

Figure 5 shows a socket plug 24 assembled with a pin plug 23. In this instance a coding element 25 is inserted into the actual socket 8. This combination will fit together since there is no pin in the pin chamber 3.

Figure 6 shows the socket plug 24 with the coding element 25 exactly as in Fig. 5, and standing opposite this a pin plug 26 of the same type as in Fig. 5. However, since in this case the relevant pin chamber 3 is provided with a projecting contact pin 4, this combination cannot be fitted together. In other words piugging of the pin 4 into the socket 8 is prevented by the presence of the coding element 25 in the socket 8. This element 25 has, at its ends, concentric bores (not shown), so that it can be removed with an appropriate tool, similar to a corkscrew.

The aforedescribed coding elements can be produced from plastics material or from metal or from any other suitable material. Also the shape of the coding elements, particularly the shape of their cross-sections may vary so long as they are capable of functioning in the manner described above.

Claims (6)

1. A multi-polar electrical plug-in connector formed with bores at defined contact positions, and contact pins and/or contact sockets retained within the bores at specific contact positions by means of securing elements, characterised in that a coding element in the form of an elongate body is inserted into the bore at at least one contact position.

2. An electrical connector as claimed in claim 1 wherein the coding element has a collar which co-operates with a securing element disposed within the bore.

3. An electrical connector as claimed in claim 2, wherein the collar is arranged approximately in the centre of the longitudinal extent of the coding element.

4. An electrical connector as claimed in claim 2 or 3 wherein the coding element has a reduced diameter region at at least one end.

5. An electrical connector as claimed in claim 1, 2 or 3 wherein the coding element has a concentric bore at at least one end.

6. A multi-polar electrical plug-in connector substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2, or Figs. 3 and 4, or Figs. 5 and 6 of the accompanying drawings.