COMPLIANT PRESS FIT PIN

Abstract: A press-fit electrical connector (10) has a compliant portion (18) formed of two, opposed, T shaped segments (22, 24). The facing legs (26, 28) of the segments are offset from one another and their interior surfaces (34, 36) do not make contact when the segments are compressed by insertion into a hole.

Description: This invention relates to an electrical connector. Modern electronic apparatus makes extensive use of printed circuit boards employing plated through holes (PTH). As an alternative to soldering connectors in these holes, it has been proposed to use connectors which engage the hole by friction only. Such connectors generally employ a compliant section for engagement to provide good mechanical and electrical contact. It is desirable that minimum damage be done to the PTH so that such connectors can be removed and replaced. The compliant connectors generally available take several forms: the "eye-of-the-needle" approach, as shown in U.S. Pat. Nos. 3,545,080; 3,634,819; and 4,206,964: the "split beam" approach, shown in U.S. Pat. Nos. 4,066,326; 4,186,982; and 4,443,053: and the "C" section, as shown in U.S. Pat. No. 4,076,356. Another technique has utilized a straight pin having a quadrangular PTH engaging section whose diagonal exceeds the PTH diameter. The latter approach causes considerable damage to the plating and is not suitable for many applications. From "L'Onde Electrique, Vol. 66 p. 13-16" an electrical connector is known, comprising two rigid portions and a compliant portion which is formed by the provision of two oppositely disposed triangular shaped segments arrayed about the longitudinal axis of the connector. The interior surfaces of the triangular shaped segments are frictionally engaged with each other, that a considerable force must be applied to compress the compliant portion of the connector. While some of the techniques work to a greater or lesser extent, all have one or more problems, such as cost of making; failure to form a good gas tight seal with the PTH; difficulty with insertion; or difficulty of removal. The object of the invention according to claims 1 and 6 is the provision of an electrical connector for PTH's which provides ease of insertion and removal with minimal plating damage. This object is accomplished, in one aspect of the invention, by the provision of an electrical connector which comprises a body having a longitudinal axis with at least one substantially rigid portion. This portion is joined to a compliant portion having a given longitudinal length measured along the longitudinal axis The compliant portion is formed by the provision of two oppositely disposed segments, said segments being substantially T-shaped in a cross sectional view and being arrayed about said axis, said segments having leg portions which project internally from bar portions and which are offset from one another so that their interior surfaces, facing each other, do not come into contact along a major portion of their length, thereby avoiding frictional engagement of said leg portions. This connector provides good mechanical and electrical contact with a PTH. Preferred embodiments are subject to the subclaims. In the following the invention will be explained with the accompanying figures. Fig. 1 is an elevational view of an embodiment of the invention; Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1; Fig. 3 is a sectional view taken along the line 3-3 of Fig. 1; and Fig. 4 is a sectional view showing the connector in a PTH. For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings. Referring now to the drawings with greater particularity, there is shown in Fig. 1 an electrical connector 10 having a longitudinal axis 12. Connector 10 has a first end 14 and a second end 16 which are substantially rigid and spaced apart. These ends may take, at their functional terminations, any desired form. For example, first end 14 may be formed to contact a printed circuit board and second end 16 may be formed as a wire wrap terminal. The spaced apart first and second ends are separated by and joined to a compliant portion 18 which has a given, split, longitudinal length 20, measured along axis 12. The compliant portion 18 is formed to provide two oppositely disposed, substantially T shaped segments 22 and 24 arrayed about axis 12. The segments 22 and 24 have leg portins 26, 28, respectively, which are offset from one another, and bar portions 30, 32, respectively. The bar portions have outer surfaces 34, 36, respectively, which are arcuate in a direction transverse to axis 12. Preferably, the radius of the arcuate surfaces 34, 36 is substantially equal to the radius of the PTH into which the connector 10 is to be inserted. Likewise, the given split length 20 is substantially equal to the thickness of the board carrying the PTH. The compliant portion 18 also is provided with an arcuate surface along the axis 12, as can be seen in Fig. 1. This longitudinal arcuate surface, extending from the first rigid portion to the widest point to the second rigid portion provides a smooth transition area eliminating any sharp corners or angles that could cause hole damage. The first and second ends 14 and 15 may be any desirable cross-section; however, square is preferred. In a preferred embodiment the connector 10 is made from 0.025″ square wire. A suitable material is phosphor bronze. The width of the compliant section 18 at the widest point is about 0.046″, for insertion into a 0.040″ diameter PTH. Thus, arcuate surfaces 34, 36 have a radius of about 0.020″. Fig. 4 shows connector 10, particularly compliant portion 18, inserted into a PTH 38 formed in a printed circuit board 40 and illustrates the substantially even compression of the T sections and good electrical and mechanical contact with the PTH 38. Because of the offset provided to legs 26 and 28, the T shaped segments 22 and 24 can be squeezed toward each other without having the interior surfaces 42 and 44 of the legs 26 and 28 come into contact along a major portion of their length, thus avoiding creating a friction surface means which can destroy or severly limit the spring action of the material. Connectors made in accordance with the teachings herein greatly enhance the art of press-fit connectors. They are simple and economical to fabricate; are easy to insert and remove; cause minimal damage to plated-through-holes; and provide good electrical and mechanical contact.

Claims: An electrical connector comprising: a body having a longitudinal axis (12) with first and second spaced apart, substantially rigid portions (14, 16) separated by and joined to a compliant portion (18) having a given longitudinal length measured along said axis (12), characterized in that, said compliant portion is formed by the provision of two oppositely disposed segments (22, 24), said segments (22, 24) being substantially T-shaped in a transverse cross-sectional view and being arrayed about said axis (12); said segments (22, 24) having leg portions (26, 28) which project internally from bar portions (30, 32) and which are offset from one another so that their interior surfaces (42, 44) facing each other, do not come into contact along a major portion of their length, said bar portions having outer surfaces which are arcuate transversely to said axis. The electrical connector of claim 1 wherein said compliant portion (18) has an arcuate surface along said longitudinal axis (12). The electrical connector of claim 2 wherein said first and second rigid portions (14, 16) are quadrangular in cross-section. The electrical connector of claim 3 wherein said connector is formed to be inserted into a plated-through-hole in a board having a given thickness and said given length is equal to said given thickness. The electrical connector of claim 3 wherein said first and second rigid portions (14, 16) are square in cross section. An electrical connector comprising: a body having a longitudinal axis (12) with a substantially rigid portion (14) joined to a compliant portion (18) having a given longitudinal length measured along said axis (12), characterized in that, said compliant portion is formed by the provision of two oppoisitely disposed segments (22, 24), said segments (22, 24) being substantially T-shaped in a transverse cross-sectional view and being arrayed about said axis (12); said segments (22, 24) having leg portions which project internally from bar portions (30, 32) and which are offset from one another so that their interior surfaces do not come into contact along a major portion of their length, said bar portions having outer surfaces which are arcuate transversely to said axis. The electrical connector of claim 4 wherein said plated-through-hole has a given radius and said bar portion arcuate surfaces have a radius substantially equal to said given radius.

Inventors: MEMCOVSKI, RHONDA L., MOORE, JAMES R., ORBANIC, ROBERT S.
Applicants: GTE PRODUCTS CORPORATION
Application year: 1987
Main classification: H01R9
IPC codes: H01R12, H01R13