GB2253523A

GB2253523A - Interference fit of contact in connector housing

Info

Publication number: GB2253523A
Application number: GB9104438A
Authority: GB
Inventors: Peter Jordan
Original assignee: ITT Industries Ltd
Current assignee: ITT Industries Ltd
Priority date: 1991-03-02
Filing date: 1991-03-02
Publication date: 1992-09-09
Also published as: GB9104438D0

Abstract

Ears (9, 10, 23, 24) of a socket contact are an interference fit in an aperture of a connector housing. The ears are formed, on part of a metal stamping, a predetermined distance apart. The ears extend transversely of rows of contacts. Contacts may engage along a slot in the connector body, the slot having inward extensions dividing the slot into locations each accommodating a contact. <IMAGE>

Description

IMPROVEMENTS RELATING TO ELECTRICAL CONNECTORS This invention relates to electrical connectors.

The present invention is especially, but not specifically, concerned with electrical connectors of the miniature type having co-operating socket and plug parts each comprising a multiplicity of electrical contact members arranged in rows and retained within individual contactreceiving apertures of an insulating housing.

Hitherto, electrical contact members of socket parts of such miniature electrical connectors have been formed from thin sheet metal (e.g. phosphor bronze) and bent to provide an enlarged section of substantially rectilinear channel shape from which extend a pair of opposed cooperating cantilever socket contacts and between which, in use of the connector, pin contacts of a plug part of the connector will be inserted. For the retention of these socket contact members within the housing, the aforesaid channel-shaped section of each contact member has been dimensioned so that, after fabrication of the contact member, the free ends of the channel section and the web of the section provide an interference fit with opposite side walls of the housing aperture accommodating the contact member.One of the problems experienced with this known contact member retention arrangement is that it is very difficult to ensure consistent precision-forming and thus dimensioning of the channel section so as to provide the requisite precise retentivity. As will be appreciated, variations in the degree of curvature that will inevitably be present in the web of the channel section will produce significant variations in the degree of interference fit of the contact member within the housing.

Another problem that arises with the existing socket connector part described above is that the interference fit forces exerted on the housing by the contact member act in the longitudinal direction of the rows of contacts and only over one part (rear) of the housing embracing the channel section so that the cumulative action of such forces and the unbalanced distribution thereof can tend to produce distortion of the housing.

The present invention is directed therefore to a construction of contact member in or for an electrical connector part which, inter alia, may be applied to miniature electrical connectors of the above-described construction for example, to obviate the aforesaid problems experienced with such connectors.

According to the present invention in its broadest aspect there is provided in or for use in an electrical connector or connector part comprising an insulating housing having at least one contact receiving opening therein, an electrical contact member which is formed with one or more laterally extending ears or the like which co-operate with the insulating housing when the contact member is inserted in the opening to provide an interference fit therewith or otherwise to provide restraint against movement of the contact member in the housing.

In carrying out the present invention the contact member or members of the connector part may be formed, as by stamping, from sheet metal. Such sheet metal contact members may each be bent or otherwise shaped to provide along its length an enlarged section of suitable crosssection which is a clearance fit in a contact-receiving opening of the insulating housing. It is especially envisaged that the enlarged section may have a substantially rectilinear channel-shaped cross-section but it should be appreciated that any other cross-sectional configuration (e.g. box-shaped, C-shaped 0-shaped etc.) could be utilised.

It is convenient to arrange that, during the bending or other shaping of an electrical contact member, the ears of the contact member for providing an interference fit within an opening of the insulating housing, or for otherwise acting to restrain the contact member in the housing, are caused to project outwardly from the enlarged section which will itself be a clearance fit in the appertaining opening of the housing.

In carrying out the invention the openings in the insulating housing will of course be of a shape and size determined in accordance with the configuration of the electrical contact members, rectangular openings being provided for receiving the aforesaid rectilinear channelshaped enlarged sections of contact members.

The configuration of the housing openings for receiving the electrical contact members may, if necessary, be adapted in some way to ensure that the contacts can only be correctly inserted into the housing openings.

The housing openings may comprise separate openings for receiving individual electric contact members, although it is contemplated that an opening, such as a slot, may effectively be divided into a plurality of sections each of which serves to accommodate an individual electrical contact member by providing the slot with projections or recesses for receiving or abutting against the ears of the contact members.

It is especially contemplated that the present invention will be applied to electrical contact members in or for use in miniature electrical connectors having a multiplicity of electrical contact members and the invention lends itself especially well to the socket part of such a connector in which the socket contact members are formed from thin sheet metal by a stamping or pressing operation followed by a bending operation which brings co-operating contacts of the socket member into an opposed position whilst causing the ears of the contact member fabricated during stamping, or pressing, to protrude from the enlarged section of the contact member so that they can provide an interference fit for the contact member within the housing opening.

As will readily be appreciated from the foregoing, the provision of projecting ears or the like on the electrical contact members for providing an interference fit, particularly when the contacts have bent enlarged sections conforming transversely to the cross-sectional configuration of the housing openings, avoids the need for precision forming of the contact members since the enlarged section will be a clearance fit in the appertaining housing opening rather than an interference fit, as in the case of the existing electrical connectors previously described.

Moreover, in the case of miniature electrical connectors comprising a multiplicity of contact members (e.g. four rows of forty eight contacts each) the interference fit ears of the contact members can be positioned in the housing so that cumulative forces exerted on the housing as a result of the interference fit of the contact members in the housing are kept to a minimum by acting in a direction transversely to the aforesaid rows of contacts. This can significantly reduce any tendency for the insulating housing to distort.

By way of example the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a fragmentary perspective view of the rear of an electrical connector part (i.e. socket part) with one socket contact member of a multiplicity of such members being poised ready for insertion into a contact member receiving aperture of the connector housing; Figures 2, 3 and 4 show the socket contact member of Figure 1 in side elevation, plan and end elevation respectively; Figure 5 shows a plan view of a thin sheet metal stamping or pressing for providing, after bending, a socket contact member according to Figures 1 to 4; Figures 6 and 7 illustrate diagrammatically known and presently proposed methods, respectively, of providing the interference fit between socket contact members and the insulating housing of an electrical connector part.

Referring to Figures 1 to 4 of the drawings, a socket part of a miniature electrical connector comprises an insulating housing 1 having a multiplicity of small rectangular apertures 2 for receiving, from the rear of the housing 1, socket contact members, one only of which is shown generally at 3 poised ready for insertion into one of the housing apertures 2.

The socket contact member 3 is formed from thin sheet or strip material (e.g. phosphor bronze), as by stamping, and comprises an enlarged section 4 which is of substantially rectilinear channel shape and which has integrally formed therewith spring contacts 5 and 6 extending therefrom in opposed relationship. The forward ends of the spring contacts are arranged for receiving between them a contact pin (not shown) of a plug part of a connector when the connector is in use. A connecting terminal for the socket contact member 3 is provided by an integral strip extension 7 of the channel section 4.

The web part 8 of the channel section 4 provides vertically disposed ears 9 and 10 the upper and lower edges 11 and 12, respectively, of which project slightly above and below the upper and lower outer surfaces of the channel section 4.

The socket contact member 3 is so shaped and dimensioned that when it is inserted into a receiving aperture 2 of the insulating housing the channel section 4 is a comfortable clearance fit in the aperture but the upper and lower edges 11 and 12 of the projecting ears 9 and 10 provide an interference fit with the upper and lower wall surfaces, respectively, of the aperture 2 in order to provide the requisite degree of contact member retentivity.

As will readily be understood, the shaping and dimensioning of the channel section 4 is not critical in the present connector construction since it is not itself required to provide for retention of the contact member 3 in the housing 1. Contact member retention is achieved solely by means of the projecting ears 9 and 10. Such a retention arrangement is particularly advantageous when the contact members of the connector are produced by stamping and bending, as can be appreciated from Figure 5 of the drawings which depicts thin stampings or pressings 13 for providing socket contact members as indicated at 3 in Figure 1, the various component parts of the contact member stampings bearing like reference numerals to the parts in Figure 1.

After being stamped out, each contact member stamping 13 is bent at right angles along the chain lines 14 and 15 so that the spring contacts 5 and 6 then face one another, as shown in Figure 1, as the section 4 takes on its channel shape, but the ears 9 and 10 remain in the same plane as the web part 8 with the edges 11 and 12 now projecting slightly beyond the upper and lower surfaces of the channel section 14 as viewed in Figure 1.Consequently, the distance between the edges 11 and 12 of the interference fit projecting ears of the contact member which can be consistently and precisely determined by the stamping operation is unaffected by the subsequent bending operation to form the channel section 4 which can lead to small variations in the shape and dimensions of the channel section which in turn could lead to problems if the free ends and web of the channel section itself were relied upon for the interference fit, as in the previously described known connector construction.

In this known construction it will be seen from Figure 6 that a channel section 16 (shown in cross-section) of a contact member 17 is an interference fit within rectangular aperture 18 of the housing by the free ends 19 and 20 of the channel section 16 bearing against the left side wall of the aperture 18 and the web 21 of the section 16 bearing against the right hand side wall of the aperture 18. As mentioned above, it will be readily apparent that variations in the degree of the inevitable curvature of the web part 21 produced during bending of a stamping 13 to provide the socket contact member will cause variations in the degree of the interference fit.

Turning now to Figure 7 which shows diagrammatically a cross-sectional view of the contact member 3 taken through the channel section of a connector part according to the present invention the web part 22 has upper and lower ears 23 and 24, respectively, which provide an interference fit with the upper and lower walls 25 and 26 of the housing aperture 27 which receives the contact member. The upper and lower limbs 28 and 29 of the channel section 4 are, however, a clearance fit within the aperture 27 thereby avoiding the above referred to problem with the known construction according to Figure 6.

Moreover, it will be appreciated from Figure 6 that the cumulative forces resulting from the interference fit are in the longitudinal direction of the contact rows whereas in the construction of Figure 7 the cumulative forces due to the interference fit of the socket contact members in the apertures of the housing are in a direction transverse to the direction of the contact rows and are thus significantly lower in the case where there are a relatively low number of rows (e.g. 4) and a relatively high number (e.g. 48) of contact members in each row. This factor is very significant in reducing the tendency for the housing of the connector part to distort due to the rear part only of the housing being subjected to these interference fit forces.

As will readily be understood from the foregoing the principles of the present invention can be applied to electrical contact members for use in many different constructions of electrical connectors including the plug and socket parts of such connectors.

Moreover, the configuration of the enlarged section part of the contact member and/or its manner of fabrication could be different (e.g. C-shaped, box-shaped or O-shaped) and the ears of the contact member could additionally or alternatively be utilised to retain a contact member in a particular position, as by restraining the contact against lateral movement within an insulating housing, by the respective ears engaging recesses provided in the walls of a slot for receiving a plurality of contact members of a row of contacts. Instead of providing the recesses for receiving the ears, the slot may include dividing projections which effectively divide the slot into a plurality of locations each of which receives a single contact member.

Claims

CLAIMS:

1. In or for use in an electrical connector or connector part comprising an insulating housing having at least one contact-receiving opening therein, an electrical contact member which is formed with one or more laterally extending ears or the like which co-operate with the insulating housing when the contact member is inserted into the opening of the housing to provide an interference fit therewith or otherwise to provide restraint against movement of the contact member in the housing.

2. An electrical contact member as claimed in claim 1, in which the contact member is formed from sheet metal.

3. An electrical contact member as claimed in claim 2, in which the contact member is formed by stamping.

4. An electrical contact member as claimed in claim 2 or 3, in which the contact member is bent or otherwise shaped to provide along its length an enlarged section of suitable cross-section which will be a clearance fit in the contact-receiving opening of the housing.

5. An electrical contact member as claimed in claim 4, in which the enlarged section has a substantially rectilinear channel-shaped cross-section.

6. An electrical contact member as claimed in claim 4, in which the enlarged section is box-shaped, C-shaped or Oshaped.

7. An electrical contact member as claimed in any of claims 4 to 6, in which during bending or shaping of the contact member a precisely pre-dimensioned part of the contact member located in the region of the enlarged section for providing the ears remains dimensionally unchanged but end portions thereof are caused to protrude from the section for engagement with the housing.

8. An electrical contact member as claimed in any preceding claim, in which the contact member comprises a socket member having a pair of opposed spring contacts for receiving between them a contact pin of a plug part of a connector.

9. An electrical contact member as claimed in claim 8 as dependent on any of claims 4 to 7, in which the pair of opposed contact members are brought into their opposed position during bending of the sheet metal contact members to form the enlarged section.

10. An electrical connector or connector part comprising a plurality of electrical contact members as claimed in any preceding claim, in which the contact members are received by individual openings of appropriate shape in the housing and arranged in one or more rows.

11. An electrical connector or connector part as claimed in claim 10, in which the transverse shape and dimensions of the contact member receiving openings in the housing and the corresponding shape and dimensions of the contact members are such that the engagement of the ears of the contact members with the insulating housing to provide an interference fit therewith is in a direction transverse to the row or rows of contacts.

12. An electrical connector or connector part of the miniature type having a multiplicity of rectangular openings arranged in rows and each accommodating an electrical contact member as claimed in claim 5, and in which the enlarged channel-shaped section of the contact member has two ears projecting laterally from opposite sides thereof which present edges making an interference fit with the opposite walls of the appertaining receiving opening so that the directions of the resultant forces are transverse to the rows of rectangular openings.

13. An electrical connector or connector part as claimed in claim 12, in which the respective configurations of the housing openings and contact members prevent incorrect insertion of the contact members in the openings.

14. An electrical connector or connector part comprising a plurality of electrical contact members as claimed in any of claims 1 to 9, in which an insulating housing of the connector or connector part has a slot therein for receiving the contact members in row formation with the laterally extending ears of the contact members engaging recesses in the walls of the slot in order to retain and/or restrain the contact members in the housing,.

15. An electrical connector or connector part comprising a plurality of electrical contact members as claimed in any of claims 1 to 9, in which an insulating housing of the connector or connector part has a slot therein for receiving the contact members in row formation the slot being provided with inwardly extending projections for effectively dividing the slot into a plurality of locations each accommodating a contact member.

16. An electrical contact member according to claim 1 substantially as hereinbefore described with reference to the accompanying drawings.

17. An electrical connector socket part substantially as hereinbefore described with reference to the accompanying drawings.