GB2060280A

GB2060280A - Preventing incorrect connection of complementary electrical components

Info

Publication number: GB2060280A
Application number: GB8030519A
Authority: GB
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1979-10-06
Filing date: 1980-09-22
Publication date: 1981-04-29
Also published as: GB2060280B

Abstract

Two complementary, substantially identical electrical components, such as hermaphroditic connectors, are each modified by the provision of a rigid bar or other protuberance (40), which bars abut each other when an attempt is made at interconnection and hence prevent interconnection. Third similar but unmodified connector (Figure 1, not shown) can still be easily connected to either of the other two connectors. This is of particular application to the connections used in the various power circuits of electrically-propelled battery-powered vehicles such as fork-lift trucks, where it is necessary to avoid connection of the "charger" and "motor" plugs and to restrict connection of the "battery" plug so that it can only be coupled with either the "charger" or the "motor" plug. <IMAGE>

Description

SPECIFICATION Preventing incorrect connection of complementary electrical components This invention relates to a means for preventing the incorrect connection of complementary electrical components, especially plugs, sockets and the like.

The present invention also relates to an electrical component having means to prevent its incorrect connection with a complementary electrical component.

The present invention will hereinafter be described with particular reference to the complementary electrical components conventionally provided on battery-powered electrically-propelled vehicles (especially fork-lift trucks) but is not to be regarded as being limited thereto.

Battery-powered electrically-propelled vehicles include an electrically-driven motor and one or more batteries which can be connected thereto to provide motive power. Unlike vehicles propelled by means of an internal-combustion engine, electrically-propelled vehicles are not provided with means to re-charge the batteries whilst the motor is running and so the batteries require periodic re-charging from a source external to the vehicle.

Thus, battery-powered electrically-propelled vehicles are provided with complementary electrical connections (a) to connect the batteries to a battery-charger and (b) to connect the batteries to the motor. Accordingiy, any one such vehicle must have three connectors, viz. one on the charger circuit, one on the battery circuit and one on the motor circuit.

In most battery-powered electrically-propelled vehicles, especially in fork-lift trucks, all three connectors are identical and are generally of the combined "maie/female" type, knownperse.

There is thus a risk that incorrect connections may be made. For example, if the connector from the battery-charger were to be connected to the motor, there could be serious damage to the motor and/or to the battery-charger. The batteries would, of course, remain uncharged. This would, in turn, lead to the vehicle being out of use while the motor was repaired and the batteries recharged.

The risks of incorrect connection, and the possible damage consequent thereon, are avoided by the present invention.

In one aspect, therefore, the present invention provides means to prevent the incorrect connection of two substantially identical complementary electrical components, the means comprising a rigid bar or other protuberance on each of said components, whereby, when said components are brought together, the bar or protuberance on one component abuts the bar or protuberance on the other component and prevents connection thereof.

In a second aspect, the present invention provides an electrical connector having a rigid bar or other protuberance attached thereto or integrally formed therewith, whereby electrical connection with a substantially identical connector having a similar protuberance is prevented.

In a preferred embodiment of the present invention, each electrical connector comprises a combined "male/female" plug, of a type known per se. The "male" portion of one plug engages the "female" portion of a second, substantially identical, plug and vice versa. Thus, each plug can be considered as having a "male" side and a "female" side. According to the invention, a rigid bar or other protuberance is attached to or integrally formed with the "male" side of one plug and to the "femaie" side of a second plug, so that connection of two plugs, each of which is provided with such a rigid bar or protuberance, is impossible.

The rigid bar or protuberance can be made of a rigid plastics material or other rigid, preferably non-conducting, material. In a preferred embodiment, the bar or protuberance is made from a rigid plastics material and attached to the plug by means of screws or nut-and-bolt assemblies. Alternatively, each plug may be injection-moulded with the rigid bar or protuberance integral therewith.

The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying informal drawings.

In the drawings: Figure 1 is a perspective view of a conventional "male/female" plug, known peruse; Figure 2 is a perspective view of the plug of Figure 1, modified in accordance with the present invention; Figure 3 is a further perspective view of the plug of Figure 1, modified in an alternative way in accordance with the present invention.

The plug shown in Figure 1 has two "male" connectors 10 and 11 and two "female" connectors 20 and 21. Connectors 10 and 11 engage the "female" connectors of a similar plug (not shown), whilst connectors 20 and 21 engage the corresponding "male" connectors.

Referring to Figure 2, a bar 30, made of a rigid material, is attached by means of screws 31 to the "female" side of the plug.

In Figure 3, a similar bar 40 is attached to the "male" side of the plug.

It will be seen that it is possible to connect the plugs of Figure 1 and Figure 2, or to connect the plugs of Figure 1 and Figure 3, but that it is impossible to connect the plugs of Figure 2 and Figure 3.

In the application of the present invention to the electrical system of a fork-lift truck, the plug shown in Figure 1 may be the "battery" plug, the plug shown in Figure 2 may be the "motor" plug, and the plug shown in Figure 3 may be the "charger" plug.

Thus, it will only be possible to connect the "battery" plug and either the "charger" or the "motor" plug. It will not be possible to connect the "charger" and the "motor" plugs, thus avoiding the dangers, described hereinabove, which are inherent in such a connection.

Claims

1. Means to prevent the incorrect connection of two substantially identical, complementary electrical components, the means comprising a rigid bar or other protuberance on each of said components, whereby, when said components are brought together, the bar or protuberance on one component abuts the bar or protuberance on the other component and prevents connection thereof.

2. Means according to Claim 1 , in which each said rigid bar or protuberance is integrally formed with its corresponding electrical component.

3. Means according to Claim 1 or 2, in which the complementary electrical components each comprise a combined "male/female" plug, of a type known per se and in which one of said rigid bars or protuberances is attached to or integrally formed with the "male" side of one of said plugs and the other said rigid bar or protuberance is attached to or integrally formed with the "female" side of the other said plug.

4. Means according to any one of Claims 1 to 3, in which each said bar or protuberance is made of a rigid, non-conducting material.

5. Means according to Claim 4, in which each said bar or protuberance is made of a rigid plastics material.

6. Means according to Claim 1, and to any one of Claims 3 to 5 when dependent upon Claim 1, in which each said bar or protuberance is attached to its corresponding electrical component by means of one or more screws or one or more nut-and-bolt assemblies.

7. Means according to Claim 2 and to any one of Claims 3 to 5 when dependent upon Claim 2, in which each electrical component is injectionmoulded so as to have the rigid bar or protuberance integral therewith.

8. An electrical component provided with means for preventing its incorrect connection with a substantially identical, complementary electrical component, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.