GB2081985A - Electrical connector - Google Patents

Abstract

An electrical contact (1) engageable with a terminal by moving the contact in a forward direction into engagement with the terminal comprises a forwardly projecting finger (4) having a rear facing shoulder (8) for latching engagement with an oppositely facing rigid shoulder on the terminal, the finger being connected to the remainder of the contact by a cross beam (5), and an auxiliary (7) for unlatching the connector from the terminal by applying torsional deformation to the cross beam, and displacing the finger to release the latching engagement. <IMAGE>

Description

SPECIFICATION Electrical connector This invention relates to electrical connectors which can be removed from a terminal by applying a small force when required but resist pulling on the cable or other conductor connected to the contact of the connector.

Connectors of this type are known in which the connector includes a forwardly-projecting resilient cantilever finger having a rear facing shoulder tor latching engagement with an oppositely facing rigid shoulder on the terminal, the free-end of the finger having an extension for engagement with a suitable tool for unlatching the connector for the terminal.

This type of connector is described in UK Patent Specification 1 080420.

An alternative form of known connector as described in UK Patent Specification No.

1463751 has a rearwardly projecting resilient cantilever finger. This connector latches to a terminal in a similar manner to the previous connector, but is released by depressing the free-end of the finger, preferably by pulling the connector housing.

Both these connectors have disadvantages.

The first connector requires the use of a special tool to release the connector from a terminal. The second connector has the disadvantage that the extension of the finger needs to be a considerable distance from the rearfacing shoulder on the finger, and hence the free-end of the finger has to be depressed a considerable amount in order to release the latching engagement of the rear-facing shoulder with the terminal.

Another form of connector is described in our European Patent Application No.

79300770.9 (Publication No. 5370) and comprises an electric contact engageable with a terminal by moving the connector in a forward direction into engagement with the terminal, a resilient cantilever finger having a rear-facing shoulder for latching engagement with an oppositely facing rigid shoulder on the terminal, the free-end of the finger having an extension for engagement for unlatching the connector from the terminal by flexing the finger to release the latching engagement, and a housing having a formation so shaped that when the housing moves in the rearward direction with respect to the contact the formation will engage the extension of the finger to release the latching engagement, allowing the connector to be removed from the terminal characterised in that the finger projects forwardly.

According to the invention an electric contact engageable with a terminal by moving the connector in a forward direction into engagement with the terminal comprises a forwardlyprojecting finger having a rear-facing shoulder for latching engagement with an oppositely facing rigid shoulder on the terminal, the finger being connected to the remainder of the contact by a cross-beam, and an auxiliary lever for engagement for unlatching the connector from the terminal by applying torsional deformation to the cross-beam, and displace the finger to release the latching engagement.

Preferably the finger is itself resilient but in some cases it might be substantially rigid and moveable only by torsional deformation of the cross-beam.

Preferably the finger and the auxiliary lever are connected to opposite sides of the crossbeam, the extension projecting rearwardly and being engageable by any suitable mechanical means, or by hand, to release the latching engagement.

Alternatively, or as well, the finger may have, at its free end, a forwardly-directed extension, and the invention also includes an electrical connector comprising an electric contact as hereinbefore described and a housing having a formation so shaped that when the housing moves in the rearward direction with respect to the contact the formation will engage the forwardly-directed extension to release the latching engagement, allowing the connector to be removed from the terminal.

Preferably the engaging formation on the housing has a flat surface oblique to the mating axis for engaging the other.

The invention further includes a two-part electrical coupling comprising a contact as herein before described and a terminal having a forwardly facing rigid shoulder for engagement with it in the manner described. Preferably the cross-beam of the contact is so shaped that when the contact is engaged with the terminal, the terminal abuts a part of the cross-beam to inhibit further relative movement.

This invention does not require the use of a special unlatching tool, and the rear-facing shoulder on the finger can be positioned at the free-end of the finger so that a small amount of movement of the free-end of the finger will release the latching engagement of the rear-facing shoulder with the terminal.

Preferably the contact, including the crossbeam, the auxiliary lever, the finger and, when present, its extension, is stamped and formed in one piece from sheet metal.

Under normal circumstances the housing will be made from insulating material and in this case, one housing may be common to several connectors.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 is a section of a perspective view of an electric contact in accordance with the invention; Figure 2 is a cross-sectional view on the line ll-ll in Fig. 3 of a coupling in accordance with the invention; and Figure 3 is a cross-sectional view on the line Ill-Ill in Fig. 2.

The sheet-metal contact shown in Fig. 1 comprises a part having a channel crosssection 2, the free ends of the arms 3 curved inwards, which engages a blade terminal (not shown). The contact 1 has a forwardly-projecting finger 4 and a cross-beam 5 pressed out from the base of the channel part 2, one end of the finger 4 remaining attached to the cross-beam 5. The finger 4 is bent to form a forward extension 6 at the free-end at an oblique angle away from the mating axis.

Attached to the opposite side of the crossbeam 5 is an auxiliary lever 7 which is also bent at an oblique angle away from the mating axis. A rear-facing tab 8 is pressed down from the forward part of the finger 4 near its free-end, to form a shoulder which can latchingly engage the edge of a hole in a blade terminal.

The forward extension 6 of the finger 4 is engageable by a suitable formation on an insulating housing within which the contact 1 may be housed, to flex the finger and release the latching engagement. When the housing (not shown) is moved backwards with respect to the contact 1 the surface of the formation engages under the forward extension 6 of the finger 4, lifting the tab 8 on the finger 4 out of the hole in the blade terminal, allowing the contact 1 to slide freely from the terminal, in accordance with the above mentioned European patent application. Alternatively, where the contact 1 is not housed in an insulating housing the finger 4 may be flexed be depressing the rearward extension 7 by hand.

By suitable modifications a formation in the housing may engage the rearward extension 7, or the forward extension 6 may be engaged by hand, to flex the finger and release the latching engagement.

The coupling 10 shown in Figs. 2 and 3 comprises a contact 11 which is very similar to that shown in Fig. 1. In this case the shape of the cross-beam 1 5 is slightly different, and the base of the channel part 12 has ridges 1 9 on which a blade terminal 20 rests. A rearfacing tab 1 8 on the finger 14 has a shoulder 21 which latchingly engages the edge of a hole 22 in the blade terminal 20. The shape of the cross-beam 1 5 prevents the blade terminal 20 being inserted too far into the contact 11.

The length of the sheet-metal blank from which these contacts may be made does not have to be increased to allow the addition of a finger, cross-beam and auxiliary lever.

The connection of the finger to a crossbeam considerably reduces the problem of set occurring in the finger where the finger is connected directly to the base of the contact.

Further the cross-beam can be altered in section to achieve the spring rate required and the operational stability of the finger.

Claims (11)

1. An electric contact engageable with a terminal by moving the contact in a forward direction into engagement with the terminal comprises a forwardly projecting finger having a rear facing shoulder for latching engage ment with an oppositely facing rigid shoulder on the terminal, the finger being connected to the remainder of the contact by a cross beam, and an auxiliary lever for engagement for unlatching the contact from the terminal by applying torsional deformation to the cross beam, and displacing the finger to release the latching engagement.

2. A contact as claimed in claim 1, in which the finger is resilient.

3. A contact as claimed in Claim 1 or Claim 2, in which the finger and the auxiliary lever are connected to opposite sides of the cross beam, the auxiliary lever projecting rear wardly and being engageable by any suitable mechanical means, or by hand, to release the latching engagement.

4. A contact as claimed in any one of the preceding Claims, in which the finger has, at its free end, a forwardly directed extension.

5. An electrical connector comprising an electric contact as claimed in Claim 4 and a housing having a formation so shaped that when the housing moves in the rearward direction with respect to the contact, the for mation will engage the forwardly directed ex tension on the finger of the contact to release the latching engagement.

6. A connector as claimed in Claim 5, in which the engaging formation on the housing has a flat surface oblique to the mating axis.

7. A two-part electrical coupling compris ing a contact as hereinbefore described, and a terminal having a forwardly facing rigid shoul der for engagement with the contact in the manner described.

8. A coupling as claimed in Claim 7, in which the cross beam of the contact is so shaped that when the contact is engaged with the terminal, the terminal abuts a part of the cross beam to inhibit further relative move ment.

9. An electric contact as hereinbefore de scribed, with reference to and as shown in the accompanying drawings.

10. An electrical connector as hereinbe fore described, with reference to, and as shown in, the accompanying drawings.

11. An electrical coupling as hereinbefore described, with reference to, and as shown in, the accompanying drawings.