GB2235596A

GB2235596A - Improvements relating to electrical connectors

Info

Publication number: GB2235596A
Application number: GB8919168A
Authority: GB
Inventors: John Covell Collier
Original assignee: ITT Industries Ltd
Current assignee: ITT Industries Ltd
Priority date: 1989-08-23
Filing date: 1989-08-23
Publication date: 1991-03-06
Also published as: FR2651383A1; GB8919168D0; DE4024478A1

Abstract

For use in an electrical connector, a pin connector part having pin contacts (12) each of which is provided with a transverse cross-sectional configuration which produces point contact between the pin contact and a co-operating spring contact or contacts of the other connector part at every position of the contacts as the two connector parts move relatively to one another during inter-engagement thereof. During such relative movement between the contacts the location of the contact point moves transversely across the spring contact. The point contact is defined by ridges (12, 14) that produce torsional forces, or matching ridges (15) that do not. This construction reduces debris build-up and grooving of the cooperating spring contact or contacts. <IMAGE>

Description

1 . - -:. '. 5 1, 1 IMPROVEMENTS RELATING TO ELECTRICAL CONNECTORS This

invention relates to electrical connectors and relates more specifically to electrical connectors of the kind comprising co-operating connector parts having respectively a plurality of pin contacts and a plurality of spring contacts for engagement with the pin contacts. The spring contacts comprise spring strips having near their free ends convex portions which engage with one side of the pin contacts or the spring contact connector part may have pairs of opposed spring contacts having inwardly facing convex portions for engaging respective opposite sides of their appertaining pin contacts.

The pin contacts of such electrical connectors are conventionally of rectangular (e.g. square) cross-section so that as the two parts of the electrical connector are brought into engagement the convex portions of the spring contacts ride along the flat surfaces of the rectangular pin contacts. The spread of the spring contact pressure over the full width of the rectangular pin contacts tends to produce an undesirably low Hertz stress and poor electrical contact between the pin contact and the spring contact. Moreover, the movement of the spring contact along the rectangular pin contact tends to cause an adverse build up of surface debris (e.g. surface oxide) which may become lodged between the convex portion of the spring contact and the flat surface of the pin contact thereby giving rise to poor electrical connection.

The foregoing disadvantage may be resolved to some extent by providing the pin contact with a curved 1.

2 surface(s) which reduces the contact pressure area between the spring contact and the pin contact ef f ectively to a point(s), thereby improving the Hertz stress but the same narrow contact path along the centre of the convex portion of the spring contact is followed each time the pin contact is inserted or withdrawn thereby tending to wear a narrow groove or trough in the protective plating in the centre of the spring Contact-. convex section.

The present invention is directed to the provision of an improved electrical connector of the kind generally described which overcomes the aforesaid disadvantages and also provides further improvements.

According to the present invention there is provided for use in an electrical connector of the general kind is hereinbefore described, a pin connector part in which the or each pin contact is provided with a transverse crosssectional configuration which produces effectively point contact between the pin contact and the co- operating strip spring contact of the other connector part at every position of the contacts as the two connector parts move relatively to one another during the inter-engagement thereof and in which the location of the contact point moves transversely across the spring contact during such relative movement.

As will readily be apparent, the configuration of the pin contact or contacts of the connector serves to increase substantially the Hertz stress by concentrating the contact pressure exerted by the spring contact or contacts on the appertaining pin contact or contacts at the points of contact between the pin and spring contacts.

In carrying out the present invention the pin contacts may be provided with a cross-section the general form of which varies progressively along the length of the pin contact so that a ridge is preferably defined along at least one surface of the pin contact which is to be engaged by the spring contact and extends transversely across the surface of the pin contact to provide the aforesaid transversely moving contact between the pin contact and the spring contact as the two connector parts are brought together.

1 1 3 Preferably, opposite surfaces of the pin contact are engaged by the respective spring contacts of a pair of spring contacts having inwardly facing convex portions for engagement with the pin contact.

In the case where two pin surfaces are engaged by the spring contacts each pin surface may effectively be provided with a ridge which extends diagonally across the pin contact surface from one end to the other to provide transversely moving point contacts between the pin contact and the spring contacts on the respective sides of the pin as the pin is moved relative to the spring contacts.

With the arrangement according to the present invention the surfaces of the pin contact on the respective sides of the ridge will act like snow plough elements which divert any surface debris to one side of the point contact between the spring contact and the pin contact as the two contacts move relatively to one another.

The diagonally disposed ridges on the respective pin contact surfaces may extend in the same direction or it may be arranged advantageously that the diagonally disposed ridges may extend in opposite directions. In the latter case torque will be exerted on the pair of spring contacts by the associated pin contact due to the spacing between the points of contact and the resultant turning effect on the pair of spring contacts. This torque will not only tend to hold the pin and spring contacts and thus the connector parts together but it will take up any slack between the spring contacts and the contact connector body part in which they are mounted.

By way of example the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 shows spring contacts of an electrical connector engaging a pin contact of a co-operating connector part; Figure 2 shows a so-called tandem spring contact arrangement of an electrical connector engaging a pin contact of the pin part of the connector; Figure 3 shows a section through the square pin 4 contact of Figure 1 engaged by the spring contacts; Figure 4 shows a section through a known arrangement in which the pin contact has convex sides engaged by the respective spring contacts; 5 Figure 5 shows an elevational view of one pin contact configuration according to the present invention; Figure 6 shows an elevational view of another pin contact configuration according to the present invention; Figure 7 shows a perspective view of a pin contact according to Figure 5 or Figure 6; Figures 8, 9 and 10 show cross-sectional views of the pin contact of Figure 5 taken in the planes A. B and C of Figure 7; and, Figures 11, 12 and 13 show transverse cross-sectional is views of the pin contact of Figure 6 taken in the planes A, B and C of Figure 7.

Referring firstly to Figure 1 of the drawings this is a diagrammatic representation of a square section pin contact 1 of an electrical connector part (not shown) which will comprise a plurality of such pin contacts spaced along and projecting from the side of an insulated connector body. The pin contact has a tapered end 2 which f orces its way between the convex ends of the opposed spring contacts 3 and 4 accommodated within connector body part 5 when the two connector parts are mated together.

An alternative connector arrangement is depicted diagrammatically in Figure 2 in which a square pin contact 6 of a pin connector part is engaged by the convex portions of tandem spring contacts 7 and 8 as the pin contact is inserted into the cavity 9 of the connector part 10.

As will be appreciated, in both of the known arrangements of Figures 1 and 2. the pin contact 1 or 6 is of square cross-section and one or both surfaces of the pin contact are engaged across the full width thereof by the strip spring contact(s). This can- be seen in Figure 3 in which the square pin contact 1 of Figure 1 is shown in section and engaged by the strip spring contacts 3 and 4.

This contact arrangement suffers from a low Hertz stress since the contact pressure exerted on the sides of j i the pin contact 1 by the spring contacts 3 and 4 is distributed across the full width of the pin contact. Additionally, as the pin contact 1 moves between the spring contacts 3 and 4 any debris on the pin and/or spring contact surfaces will tend to build up in front of the sliding spring contacts and may finally become lodged between the pin contact 1 and the spring contacts 3 and 4 in the fully inserted condition of the pin contact thereby leading to electrical connection problems.

Pin contacts having convex sides as illustrated in Figure 4 may alleviate the situation to some extent since the contact pressure between the pin contact 11 and the spring contacts 3 and 4 is concentrated into the small areas or points of engagement between the pin contact and the spring contacts and the build up of debris (e.g. surface oxides) during insertion of the pin is unlikely to be significant. However, the contacting area of the pin 11 with each of the spring contacts 3 and 4 is constant and in time will tend to produce a central groove or trough in the protective plating (e.g. gold) on convex parts of the spring contacts 3 and 4. 1 Referring now to Figure 5, 7 and 8, 9 and 10 of the drawings these show one embodiment of the invention. As will be appreciated from Figure 5, opposite sides (i.e. top and bottom sides as viewed in Figure 5) of the pin contact 12 have oppositely inclined or pared away sections which provide surface ridges or spines 13 and 14 on these opposite pin sides. The cross-section of the pin 12 in the planes A, B and C of Figure 7 can be seen in Figures 8, 9 and 10, respectively. The effect of the progressive change in cross-section as will be apparent from the Figures by the diagonally disposed ridges 13 and 14 is to cause the points of contact between the pin sides and the spring contacts 3 and 4 to move transversely across the spring strip contact as the pin is inserted between or withdrawn from the spring contacts. This transverse shifting of the points of contact serves to distribute wear across a substantial part of the spring contact strip whilst maintaining the high Hertz stress by concentration of the spring contact pressure at 1 6 is the points of contact between the pin and the strip spring contacts.

The location of the points of contact along the ridges 13 and 14 between the pin contact 12 and the spring contacts 3 and 4 and the contact pressure exerted at these points produce a torsional force except when the contacts are at position shown in Figure 9. This torsional force will assist in maintaining the connector -partS in engagement whilst taking up any play between the spring contacts 3 ancr4 and the appertaining insulated connector body part.

In the other embodiment of the invention depicted in Figures 6, 7 and 11, 12 and 13 the ridges 15 on the contact pin 16 follow the same diagonal path and consequently the points of contact between the pin and the respective spring contacts throughout insertion of the pin contact are correspondingly positioned along the width of the spring contact convex portions and thus no torsional forces are produced as in the case of the previously described embodiment. As will readily be appreciated from the foregoing description of the invention, pin contact configurations of other forms could alternatively be used in order to embrace the principl and spirit of the present invention by which the points of contact between the pin contact(s) and the co-operating spring contact(s) move transversely relative to the direction of insertion and withdrawal of the pin connector part into or from the spring contact part of the connector.

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Claims

CLAIMS:

1. For use in an electrical connector, a pin contact connector part, in which the or each pin contact is provided with a transverse crosssectional configuration which effectively produces point contact between the pin contact and a convex portion of a co-operating spring strip contact of another part of the connector at every position of the respective contacts as the two connector parts move relatively to one another for the inter-engagement therebetween and in which the location of the point contact effectively moves transversely across the spring strip contact during such relative movement.

2. A spring contact connector part as claimed in claim 1, in which the transverse cross-sectional configuration of the pin contact varies progressively along the length of the pin contacts so that a ridge is def ined on at least one surf ace thereof which is to be engaged by a spring strip contact and the ridge extends transversely across the pin contact surface to provide the transversely moving point contact between the pin contact and the spring contact.

3. A pin contact connector part as claimed in claim 2, in which the ridge is formed by the pin contact surface being pared away or otherwise declining on both sides of the ridge.

4. A pin contact connector part as claimed in claim 2 or claim 3, in which the ridge extends diagonally across the pin contact surface.

5. A pin contact connector part as claimed in any preceding claim, in which the pin contact is engaged on opposite sides by inwardly facing convex portions of opposed spring strip contacts and in which the transverse crosssectional configuration of the pin contact provides for transversely moving the point contacts between the pin contact and the respective spring strip contacts on opposite sides of the pin contact.

6. A pin contact connector part as claimed in claims 4 and 5, in which ridges extend across the opposite sides of the pin contact to provide the transversely moving point contact action.

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7. A pin contact connector part as claimed in claim 6, in which the ridges on the opposite sides of the pin contact extend diagonally across the the pin contact in the same direction.

8. A pin contact connector part as claimed in claim 6, in which the ridges on the opposite sides of the pin contact extend across the pin contact in opposite directions.

9. Ail electtrical connector pj-n part substantially as hereinbefore described with reference to Figures 5, 7, 8, 9 and 10 of the accompanying drawings.

10. An electrical connector pin part substantially as hereinbefore described with reference to Figures 6, 71 11, 12 and 13.

11. An electrical connector including a connector pin 15 part as claimed in any preceding claim.

Published 1991 at The Patent Office. State House. 66/71 High Holborn. London WCIR4TP. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point, Cwmielinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid, St Mary Cray, Kent