COMPLIANT CONNECTOR

Abstract: An electrical connector post or pin (11) for insertion into a hole in a printed circuit board to establish contact with a conductive lining in said hole, the connector (11) being constituted by an elongated flat blank of conductive material bent or folded and shaped to have a board engaging zone (12, 22, 34, 35, 42) intermediate its ends.

Description: Description COMPLIANT CQN^ECTOfi Technical Field This invention relates to contact, connector or terminal elements for use with electronic circuit boards having pe rforations which are lined with conductive material, as part of a circuit printed on one or both sides of the board. Back g round Art In the electronic equipment industry, an important problem arises in the rapid and accu rate assembly of perforated printed circuit (PC) boards with connector posts, pins or points for connection to other components in the circuit. The holes in a circuit board are either drilled or punched and some or all of the holes may then b e lined with a plating of conductive material, in electrical contact with one or both of the circuits printed on the adjacent su rfaces. The holes are very small and their diameters may not be uniform, either before or after plating, so that connector posts of a fix ed uniform size cannot be relied on to provide uniformly good electrical contacts, A post which is smaller than the hole may fail to make a good electrical connection, while forcing a post into a smaller hole can damage the board and/or deform the post. Objects of the Invention It is accordingly an object of the invention to provide a connector post or pin having a cross-section of such configu ration and size that it will make good electrical contact with the plating in a circuit board hole having maximum diameter and will also be able to contract as may be required upon introduction into a hole of small size, while continuing to m aintain good electrical contact with the plating in the hole. It is a fu rther object of the invention to provide a connector post or pin having a compliant portion between its end portions, said compliant portion being adapted to make good • electrical contact with the plated surface of any circuit board hole into which it may be introduced. It is another object of the invention to provide a design for the cross-section of an intermediate portion of a connector post or pin which is adaptable both to a post or point intended to engage in a circuit board hole without substantial penetration of the board, and to a pin intended to engage in a circuit board hole and to extend beyond the board for attachment to some other element of the intended circuit. It is a still fu rther object of the invention to provide certain improvements in the form and arrangement of the structu ral featu res by which the above named and other objects may effectively be attained. Disclosure ς>f invention The invention, in each of its embodiments, resides in the provision of an intermediate portion of the connector which is bent or folded, and provided with slits or slots, to form a more or less tubular portion which presents an effective diameter large enough to have a snug interference fit with the wall of a plated hole, of any anticipated diameter, in a printed circuit board. The enlarged intermediate portion may have an outer surface of partial cylindrical form or may be completely cylind rical, or oval in cross-section. In no case does the formation of slits or slots reduce materially the conductive capacity of the connector. Brief Description of the Drawings Practical embodiments of the invention are shown in the accompanying drawings wherein: Fig. 1 represents a detail elevation of a post or point wherein the intermediate portion is provided with longitudinal slots to permit an increase in diameter; Fig. 2 represents a bottom end view of the post or point shown in Fig. 1; Fig. 3 represents a section on the line III-III of Fig. 1 ? Fig. 4 represents a section, as in Fig. 3, of a slightly modified post or point; Fig. 4 represents a section, as in Fig. 4, showing the post or .point of.- Figs. 3 and 4 inserted in a hole in a PC board; F ig . 5 r ep r e s ents a d etail elevation of the intermediate portion of a post or point wherein the increased effective diameter results f rom the bending of spaced wall portions into outwardly projecting ϋ-shaped ridges, separated by longitudinal slots; Fig. 6 represents a section on the line VI-VI of Fig. 5; F ig . 7 r ep re s ents a d etail elevation of the intermediate portion of a post or point wherein a final configuration similar to that shown in Figs. 1 to 3 is achieved from an elongated blank which is folded 180o at the bottom end; Fig. 8 represents a section on the line VIII-VIII of Fig. 7; Fig. 9 represents a bottom end view of the post or point shown in Fig. 7, on an enlarged scale. Modes for Carrying Out the Invention The connector pins illustrated in Figs. 1 to 9 are adapted for use particularly in situations where no connection to the lower end of the pin is required. In each case it will be understood that the upper end of the post is integral with the stem, whether shown or not, to be connected into an electronic circuit. The post or pin 11, shown in Figs. 1 to 3, is made from a flat blank which is formed into a cylinder having a larger diameter portion 12, between shorter sections 13, 14 of an intermediate diameter and a snub-nosed lower end section 15 with the smaller diameter. Tapering transition zones 16 are formed between 12-13, 12-14 and 14-15. The portion 12 is provided with diametrically opposite longitudinal slots 17, 18, the slot 17 being conveniently located along the seam line 19, constituted by the meeting edges of the folded blank. The diameter of the portion 12 is calculated to be slightly greater than the maximum diameter likely to be encountered in a plated hole of a PC board. Since each end of each slot extends through the adjacent transition zone 16, the remaining walls of the portion 12 are compliant enough to fit readily into any normal PC board holes and to maintain good contact with the conductive lining thereof. The small diameter end section 15 is adapted to lead the post into its intended hole and the tapered transition zones facilitate entry of the posts snugly into holes of varying diameters. Fig. 4 shows a cross-section of a slightly modified post or pin 21 wherein the walls of the portions 22, separated by slots 27, 28, are not concentric with the whole unit, as in Fig. 3, but are defined by arcs on centers 29" offset from the unit center 29'. Each slot 27, 28 is an enlargement of a slit from which no material has been removed, the slit developed into slot 27 being the seam between vertical edges of the blank. Fig. 4A shows the point or pin of Fig. 4 inserted in a PC board hole having a diameter of maximum compatibility, i.e„ the post walls fitting closely against the wall of the hole. The post or pin 31, shown in Figs. 5 and 6, has a compliant portion formed, as in Figs. 1 to 3, from a flat blank which is bent into a cylinder and provided with longitudin ally disposed, diametrically opposite slots, 32, 33. The walls of the cylinder between . the slots are then crimped into 180 o fold ed posts 34, 35 with U-shaped cross-sections, the outer su rfaces of the posts being spaced to project beyond the circumference of the cylinder from which they are formed, as clearly shown in Fig. 6. Above and below the slotted and crimped portion there remain cylind rical zones 36, 37 (comparable to sections 13, 14 in Fig. 1) with an intermediate diameter, and a lower end section 38 (lik e end section 15) is provided below the zone - 37. Tapering transition zones 39 are provided between portions of varying diameters. The post or pin 31 functions lik e post or pin 11 upon introduction into a PC board hole. The resiliency of the posts 34, 35 may be less than that of the compliant walls 12 (Figs. 1-3), but that characteristic can be determined by selecting metal of an appropriate gauge. A somewhat different concept is introduced in the manufactu re of the post or pin 41 shown in Figs. 7, 8 and 9, namely the provision of a blank which can be fold ed on itself endwise to bring formed cong ruent semi-cylindrical shells together in facing relationship where they constitute a cylindrical body. The external appearance of the connector is quite similar to that of the connector shown in Fig. 1 but the difference in manufactu ring technique is well illustrated in Fig. 8. The elongated blank has a narrow portion which, when sharply folded at 42, constitutes the 2-ply lower tail portion 43. Wider portions of the blank are shaped into the semi-cylind rical shells 44, 45 having intermediate diameter portions 46, 47 above and below the larger diameter main body 42. The edges of the shells are cut away in the zone of the body 48 to provide longitudinal slots 49 along the line of cleavage between the facing edges of the folded blank. A stem 50 is integ ral with the shell portion 44 and extends beyond the connector in any desired configuration for association with other elements of the circuit. The body 48 is somewhat flattened to assume an oval cross-sectional shape, as shown in the bottom end view of Fig. 9, the protruding curved ends 51 of the oval assuring good electrical contact with the lining of a PC board hole into which the connector is inserted. In each of the embodiments shown in Figs. 5 to 9, the cylin d r i c al c on n ecto r b ody i s p rov id ed with a non-circular portion having a major outside diameter larger - than the diameter of any plated (lined) hole lik ely to be associated. The- structu re of each connector body is such that it is effectively compliant (resilient) in the direction of its major diameter, such resiliency being a specific form of the multi-directional resiliency (along a plu rality of radii) exhibited by the connectors shown in Application Serial No. 556,775, of which this application is a continuation-in-part. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain ch anges m ay be m ade in the above article without departing f rom the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims: The Claims What I claim is: 1. An electrical connector element for insertion into a hole in a printed circuit board to establlish contact with a conductive lining in said hole, the connector being constituted by an elongated flat blank of cond u ctive material having a board-engaging zone con stituted by segments of substantially arcuate cross-section and of uniform radial thickness, with effective resiliency along at least one diameter, the segments of the board-engaging zone being separated by two diametrically opposite longitudinal slots extending throughout substantially the entire length of said greatest diameter zone. 2. An electrical .connector element according to claim 1 wherein the board-engaging zone has an oval cross-sectional form. 3. An electrical connector element according to claim 2 wherein the board engaging zone is constituted by segments which are folded through substantially 180o to form diametrically opposite posts. 4. An electrical connector element according to claim 1 wherein the flat blank is formed into spaced semi-cylind rical shells having portions of different diameters which are folded together edge-to-edge, the board-engaging zone having the g reatest effective diameter. 5. An electrical connector element according to claim 4 wherein the board-engaging zone is provided with two diametrically opposite longitudinal slots extending throughout substantially the entire length of said greatest diameter zone.

Inventors: SEIDLER JACK, SEIDLER, JACK
Applicants: NORTH AMERICAN SPECIALITIES, NORTH AMERICAN SPECIALTIES CORPORATION
Application year: 1985
Main classification: H01R13
IPC codes: H01R13