US3426313A - Printed circuit edge connector - Google Patents

Description

Feb.'4, 1969 T. H. WYCHECK 3,426,313

PRINTED CIRCUIT EDGE CONNECTOR Filed April 10, 1967 Sheet of 3 F1611 Fr Filed-April. 10. 1967 v Sheet 2 Fb-4 1969 T.H.WYHEK 3,42 ,313

PRINTED CIRCUIT EDGE CONNECTOR Feb. 4, 1969 1-. H. WYCHECK Q 3,

Filed April 10. 1967 United States Patent 3,426,313 PRINTED CIRCUIT EDGE CONNECTOR Thomas Henry Wycheck, Harrisburg, Pa., assiguor to AMP Incorporated, Harrisburg, Pa. Filed Apr. 10, 1967, Ser. No. 629,438 US. Cl. 339-74 Int. Cl. H01r 13/62, 13/50; Hk 1/06 5 Claims ABSTRACT OF THE DISCLOSURE Background of the invention A common type of printed circuit edge connector comprises an insulating housing having a plurality of contacts therein and having a trough-like opening on the one side which is adapted to receive the edge portion of a printed circuit board or the like. When the housing is mounted on the edge of the board, the contacts engage, and make electrical contact with, the conductors on the surface of the printed circuit board.

When the connector is applied to the board, the contacts, in most connectors of this type, are moved relatively over the surfaces of the printed circuit paths on the board. This effect is desirable to some extent in that the relative movement of the contacts with respect to the printed circuit board scrapes any oxide or dirt film which may exist on the circuit paths and thereby contributes to a low resistance electrical connection between the contacts and the boards. However, this same effect is undesirable in that the contacts and the circuit paths are frequently plated with gold. If the force imposed by the contacts on the paths is unduly high, the gold will rapidly wear off the contact area of the paths and the advantages of the gold plating will be lost. Usually, the contact is designed such that a relatively light contact pressure between the contacts and the conductor paths on the board is achieved so that some cleaning action will be achieved by relative movement of the contacts with respect to the circuit paths without undue wear. Most presently available designs therefor constitute compromises which minimize the wear of the contact while achieving the necessary contact force.

The present invention is directed to the achievement of a printed circuit edge connector which can be applied to the board without relative movement of the contact with respect to the circuit paths if desired. At the same time, the present invention permits the achievement of a very slight amount of relative movement for cleaning purposes if desired. The invention thus achieves a high degree of control over the two variables, contact force and relative movement of the contacts with respect to the board, discussed above.

In accordance with a preferred embodiment of the invention, connector housing has a plurality of tuning sides of the board and make electrical contact with conductors on the board surface. A camming member or spreader member extends through the housing and between the legs of the contacts and is provided with spaced-apart enlarged portions. This camming member is movable relative to the housing in a manner such that when the enlarged portions of the camming member are between the legs of the contacts, the contact legs are resiliently spread apart so that the board can be inserted or the connector can be applied to the edge of the board without any engagement between the contact legs and the surface of the board. After the connector has been applied to the board, the camming member is shifted a relatively short distance with respect to the connector housing to permit the legs to move resiliently towards each other and into engagement with the surface of the board. An additional feature of the invention permits the legs to be moved laterally a short distance after they have engaged the board thereby to lightly scrape the surface of the conductor paths of the board in a controlled manner.

In the drawings:

FIGURE 1 is a perspective view of a preferred embodiment of the invention showing one half of a connector housing and showing a printed circuit board in phantom, the parts being in the positions they occupy when the contact portions of the contacts are in engagement with the conductors on the board;

FIGURE 2 is a view similar to FIGURE 1 but illustrating the manner in which the contacts are mounted in the connector housing;

FIGURE 3 is a view taken along the lines 3-3 of FIGURE 1 but showing a complete connector housing in accordance with the invention;

FIGURE 4 is a view taken along the lines 44 of FIGURE 1 and showing the positions of the parts when the contacts are cammed out of engagement with the printed circuit board by the camming member;

FIGURE 5 is a view similar to FIGURE 4 but showing the positions of the parts when the contacts are in engagement with the board; and

FIGURE 6 is a view taken along the lines 6-6 of FIGURE 1 and showing the end portions of the contacts disposed against the conductors of the board.

Referring first to FIGURE 1, a preferred embodiment of the invention comprises a connector 2 which is adapted for use with a printed circuit board shown in phantom at 4 and which comprises a pair of similar housing sections 10, 10' cemented or otherwise secured to each other along a medial plane. This housing can be made as a unitary molding if desired. The two sections 10, 10' are mirror images of each other and, when secured together, define a trough-like opening 12 on the side of the connector which is adapted to receive the edge portion of the printed circuit board.

A plurality of contact terminals generally indicated at 6 are mounted in the housing in side-by-side parallel relationship, each terminal comprising a pair of coextensive contact legs 14, 16 extending from a yolk portion 17. A post or similar contact end portion 8 extends from the lefthand end of the contact shown in FIGURE 3 and through the suitable opening in the housing. The post is adapted to be electrically connected by any suitable means, for example, by a wrap-type or clip-type connection, to a conductor extending externally of the printed circuit board.

The sections 10, 10' of the housing are provided with a plurality of spaced-apart barrier ribs 18 on the sides of the opening 12, these barriers having elevated inner end portions 20. The contacts are positioned between adjacent barriers and extend into slots 22 in the rearward portions 25 of the block as best shown in FIGURE 2.

It will be noted that the portions 24 of the slots 22 which are adjacent to the gap 27 are slightly inclined relative to the planes of the contacts mounted in the cavity. The reason for this structural feature will be described more fully below. The contacts 6 can be mounted in the housing 2 by insertion from the left as viewed in FIGURES 2 and 3 until the post portions 8 project beyond the rearward side of that housing.

A spreader member or camming member 26 extends transversely through the block 10 and between the spacedapart legs 14, 16 of the contact members. This spreader member, which is of a suitable firm insulating material, has a generally rectangular cross-section and has a plurality of spaced-apart camming portions 28, 30 on opposite sides. The camming portions 30 are parallel to the sides of the spreader member, the width of the spreader at the portions 30 being substantially equal to the spacing between the opposed ribs or barriers 18. The portions 28 incline inwardly and towards the axis of the spreader member and merge with portions 31 which define a plurality of spaced-apart necks. The downwardly facing shoulders as viewed in FIGURE 5 defined by the enlarged portions 30, are adapted to bear against the sides of the contacts as shown in this figure. The upper end or forward end of the spreader is rounded as shown at 32 to facilitate its insertion through the connector block and its lower end as viewed in FIGURE 1 is enlarged as shown at 34 so that it can be gripped and moved between the position shown in FIGURES 4 and 5. Referring to FIGURE 3, it can be seen that the individual contacts have constricted portions 36, 38 on the legs 14, 16 these constrictions being in the form of ears which define leftwardly facing shoulders against which the spreader member bears.

In use, and when it is desired to assemble the connector to a printed circuit board, the spreader member is moved laterally with respect to the housing until it occupies the relative position of FIGURE 4 in which the legs bear against the sides 30 of the spreader and are resiliently biased away from each other so that their ends are spaced-apart by a distance greater than the thickness of the printed circuit board 4. The board can then be inserted into the opening 12 of the housing as shown in FIGURE 3 and the spreader or camming member 32 can be moved downwardly to the position of FIGURE 5. Such movement of the camming member permits the contact leg portions of the contacts to move resiliently towards each other and into engagement with the conductors on the surface of the board.

As previously noted, it is desirable to achieve a limited and controlled amount of relative movement between the contacts and the conductor paths 5 of the board when the connector is mounted on the board in order to clean the contacts and the conducting paths and thereby achieve an optimum electrical connection. A-limited amount of relative movement can be achieved by merely moving the spreader member 26 downwardly a short distance from the position shown in FIGURE 5 by pulling downwardly on the handle portion 34 of the spreader. Since the contact legs are in engagement with the shoulders 29, the camming member will pull these legs downwardly and over the surface of the conductors 5. When the camming member is released, the contact legs of the contacts will return to their initial positions. The limited relative movement of the contact legs will have the effect of breaking any extremely thin oxide film on the conductor paths and/or removing any dirt or grease which may be on the conductors.

The principles of the invention are, of course, applicable to connectors other than the connector of the type shown. For example, many printed circuit boards have 4 conductors on only one side and it is feasible to utilize the principles of the invention with contacts designed for such boards. The spreader member would be substantially as shown but would bear against the housing on one side rather than against one leg of the contact member.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

What is claimed is:

1. In an electrical connector of the type comprising an insulating housing having a recess on one side thereof for reception of a circuit card or the like and having a plurality of contact terminals therein, said terminals extending into said recess and being adapted to engage said card, the improvement comprising a camming member in said housing extending in said recess transversely of said contact terminals and parallel to said one side of said housing, said camming member having a series of camming means thereon for engagement with each of said contact terminals, said camming member being axially movable between first and second positions relative to said contacts, said contacts being out of engagement with a panel when said camming member is in said first position and being in engagement with said panel when said camming member is in said second position whereby said panel can be assembled to said connector when said camming member is in said first position without engagement between said contacts and said panel, and said camming member can be then moved to said second position to engage said contacts with said panel.

2. A device as set forth in claim 1 wherein said camming means are in engagement with said contacts when said camming member is in said first position, said camming means holding said contacts out of engagement with said panel.

3. A device as set forth in claim 2 wherein said contacts are fork-type contacts having a pair of spaced-apart tines, said camming member extending between said tines of said contacts.

4. A device as set forth in claim 3 wherein said camming member has shoulder means adjacent to each of said camming means, said shoulder means being engageable with said tines to move said tines laterally when said camming member is in said second position and is moved axially thereby to elfect a to-and-fro wiping movement of said tines on said panel.

5. A device as set forth in claim 3 wherein said recess comprises a trough on said one side of said housing, said tines extending along opposite sides of said trough, said camming member extending through said trough and between said tines.

References Cited UNITED STATES PATENTS 2,857,577 10/1958 Vanderpool 339- X 3,022,481 2/1962 Stepoway 33975 3,114,587 12/1963 Herrmann 33975 3,329,926 7/1967 Aksu et al. 339-75 X MARVIN A. CHAMPION, Primary Examiner.

JOHN R. MOSES, Assistant Examiner.

US. Cl. X.R. 339l7, 176

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