GB2121620A

GB2121620A - Connectors pins for printed circuit boards

Info

Publication number: GB2121620A
Application number: GB08315532A
Authority: GB
Inventors: Trevor Armistead
Original assignee: Oxley Developments Co Ltd
Current assignee: Oxley Developments Co Ltd
Priority date: 1982-06-08
Filing date: 1983-06-07
Publication date: 1983-12-21
Also published as: DE3320672A1; DE3320672C2; GB8315532D0; FR2528242A1

Abstract

A metal connector pin for use with printed circuit boards provided with through-plated holes has a plug portion (14) which comprises a plurality of generally axially extending legs (16, 18), at least one of which contains an outwardly directed kink (20) for resiliently engaging the side of the hole. <IMAGE>

Description

SPECIFICATION Connector pins for printed circuit boards The present invention relates to connector pins for use with printed circuit boards and is concerned particularly with such pins for use with printed circuit boards havingthrough- plated holes.

Some printed circuit boards employ through-plated holes whereby metal layers on two opposite side surfaces, and sometimes also one or more intermediate embedded metal layers, of the board can be electrically connected. Such through-plated holes also serve to receive metal connector pins which enable electrical connection to be made to that part of the circuit, for example to act as terminals for receiving connection leads or for receiving the terminal leads of one or more components of the circuit.

Conventional metal pins for this purpose have employed a plain cylindrical shank portion which is force fitted, i.e. an interference fit, into the selected through-plated hole. A disadvantage of this arrangement is, however, that the force fitting of such pins can damage the through-plating and even break the connection altogether between two or more of the metal layers of the board.

It is an object of the present invention to provide a connector pin for use with printed circuit boards having through-plated holes which is less likely to damage the throughplating during insertion and retraction.

In accordance with the present invention, a metal connector pin for use with printed circuit boards having through-plated holes has a plug portion for insertion into the throughplated hole which comprises a plurality of generally axially extending legs, at least one of which contains an outwardly directed kink for resiliently engaging the side of the hole.

Conveniently, the legs are fabricated by making a longitudinal slot in an initially cylindrical portion of the pin, one of the legs then being bent to form the kink.

Preferably, the slot is located slightly off the central longitudinal axis of the pin so that the legs are of unequal cross-sectional area, said one of the legs which is kinked being chosen to be the leg of smaller cross-sectional area.

The pin also has a portion for connection to one or more connection leads or components.

Preferably, the latter portion is separated from the plug portion by a shoulder which serves to limit the penetration of the plug portion into the hole.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of one embodiment of a pin in accordance with the present invention, from beneath and one end; Figure 2 is a perspective view of the pin of Fig. 1 from beneath and the opposite end; Figure 3 is a side view of the pin of Figs. 1 and 2; Figure 4 is an end view of the pin of Figs.

1 to 3; Figure 5 is an opposite end view of the pin of Figs. 1 to 3; Figure 6 is a side view of a second embodiment of a pin in accordance with this invention; Figure 7 is an end view of the pin of Fig. 6; Figure 8 is a cross-sectional view showing a pin in accordance with the present invention inserted into a conventional through-plated hole; and Figures 9 to 13 are a perspective rear view, a perspective front view, a side view, a rear view and a front view, respectively, of a further embodiment in accordance with the invention.

The pin of Figs. 1 to 5 comprises a cylindrical shank 10 which, when the pin is applied to a printed circuit board (not shown), is to project from the board for receiving one or more connecting leads or terminations, for example by soldering, or for receiving a selectably detachable connection such as a flying socket. The shank 10 is connected by a thickened shoulder 12 to a plug portion 14 which is to be inserted into the through-plated hole, the plug portion being fabricated by making a longitudinal slot in an initially cylindrical end portion whereby to form two initially parallel legs 16, 1 8 which are uniformly separated by the width of the slot. Preferably, the location of the slot is displaced slightly from the pin axis so that the cross-sectional area of the leg 1 6 is greater than that of the leg 18.The leg 18 is then bent as shown in the drawings so that it contains a permanent, outward kink 20 at approximately its midlength postion. As best seen in Fig. 3, the kink 20 causes the plug portion 14 to have a local diameter in the region of the kink which is arranged to be slightly greater than that of the through-plated hole into which the pin is to be inserted so that when the plug portion is introduced into the through-plated hole, the kinked leg 1 8 is resiliently deformed inwarldy and engages the side of the hole with a force which holds the pin firmly in position but without damage to the through-plating. The pin can, of course, also be withdrawn easily from the hole, again without likelihood of damage to the through-plating.

If required, the pin can then be soldered or otherwise permanently affixed in its inserted position. The shoulder 1 2 acts, of course, to limit the penetration of the plug portion 14 into the through-plated hole.

The pin can be made of any suitable metal.

For example, it can be made of brass in which case the kink 20 can be formed by simply bending beyond the elastic limit of the material and no other treatment is necessary. If the pin is made from a material such as spring beryllium copper, on the other hand, heat treatment would be required to set the kink.

The abovedescribed pin thus has the advantage over the known interference fit device that the pin can be inserted and withdrawn with considerably less likelihood of damage to the trough-plating.

Another advantage of the present pin is that the tolerance on the hole size into which it can be fitted is less important than in the case of interference fit pins where hole diameter is critical. Thus, the need for high tolerance machining of printed circuit board holes is reduced by the use of the present pin.

The pin shown in Figs. 6 and 7 differs from that of Figs. 1 to 5 only in that the plain shank portion 1Q of the latter embodiment is replaced by a pair of legs 22, 24 which together form a generally U-shaped socket.

The legs are both bent inwardly at about their mid-lengths to form a construction 26 for holding components in place in the socket.

This socket can, for example, facilitate socalled "select on test" applications by accommodating the axial lead of the component being selected, the axis of the component lead being disposed perpendicular to the axis of the pin in this case.

Other socket or shank configurations for the portion 10 could equally well be used with the plug portion of the present invention.

Fig. 8 shows a pin 28 in accordance with this invention (which can be, for example, of the type shown in Figs. 1 to 5 or Figs. 6 and 7) when inserted into a conventional throughplated hole 30. In this case, the hole 30 is formed in a board 32 fabricated from three electrically conductive metal layers 34, 36, 38 which are separated electrically by means of electrically non-conductive sheets 40, 42.

The through-hole 30 in this structure has a metal plated surface 44 which electrically interconnects the metal layers 34, 36, 38.

Thus, when the pin 28 is inserted into the hole 30 it becomes electrically connected to all three layers 34, 36, 38.

The pin of Figs. 9 to 13 differs from that of Figs. 1 to 8 in that it has two kinked legs 50a, 50b disposed on opposite sides respec- tively of a central, elongate spigot 52. The spigot has shank portion 52a of rectangular section and an outer end portion 52b of circular section, the latter portion providing a location for the connection of further compo- nents, as required.

Claims

1. A metal connector pin for use with printed circuit boards having through-plated holes, the connector pin having a plug portion for insertion into the through-plated hole which comprises a plurality of generally axially extending legs, at least one of which contains 3n outwardly directed kink for resiliently engaging the side of the hole.

2. A connector pin as claimed in claim 1, wherein the legs are fabricated by making a longitudinal slot in an initially cylindrical portion of the pin, one of the legs then being bent to form the kink.

3. A connector pin as claimed in claim 2, wherein the slot is located slightly off the central longitudinal axis of the pin so that the legs are of unequal cross-sectional area, the leg which is kinked being the leg of smaller cross-sectional area.

4. A connector pin as claimed in claim 1, 2 or 3 wherein the pin also has a portion for connection to one or more connection leads or components, the latter portion being separated from the plug portion by a shoulder which serves to limit the penetration of the plug portion into the hole.

5. A connector pin as claimed in claim 4, wherein said connection portion comprises a pair of legs which together define a generally U-shaped socket, the latter legs being both bent inwardly at about their mid-lengths to form a construction for holding components in place in the socket.

6. A connector pin as claimed in claim 1 having two said kinked legs, whose kinks are oppositely directed for engaging opposite sides of said hole.

7. A connector pin as claimed in claim 6 wherein said two kinked legs are disposed on opposite sides of a third, straight leg disposed on the longitudinal axis of the connector pin.

8. A connector pin as claimed in claim 7 wherein the third leg has an inner shank portion of rectangular section and an outer portion of circular section.

9. A connector pin constructed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.