US 3670288 A
Disclosed is a connector for receiving the edge of a printed circuit board, ceramic substrate or other circuit boards of the like. The connector contains a plurality of pre-twisted contacts that are untwisted for zero-force insertion of a circuit board after which they are released to return toward their original position making electrical contact with such board.
Description (OCR text may contain errors)
United States Patent Evans 51 June 13, 1972  TORSION CONTACT ZERO-INSERTION FORCE CONNECTOR  inventor: William Robert Evans, Hummelstown, Pa.
 Assignee: AMP Incorporated, Harrisburg, Pa.
 Filed: Feb. 16, 1971 [2 1] App]. No.2 115,358
52 us. Cl. .339/74 12, 339/176 MP  .1101: 13/62  Field of Search ..339/74, 75, 176
 References Cited UNITED STATES PATENTS 3,526,869 9/1970 Conrad et al ..339/75 MP 3,553,630 1/1971 Scheingold et a1 ..339/74 R Primary Examiner-Joseph H. McGlynn Attorney-William J. Keating, Ronald D. Grefe, Gerald K. Kita, Frederick W. Raring, Jay L. Seitchik and John P. Vandenburg  ABSTRACT Disclosed is a connector for receiving the edge of a printed circuit board, ceramic substrate or other circuit boards of the like. The connector contains a plurality of pre-twisted contacts that are untwisted for zero-force insertion of a circuit board after which they are released to return toward their original position making electrical contact with such board.
7 Claims 12 Drawing Figures PATENTEDJUN 13 1972 v sum 2 or 5 PKTEN'TEDJUM 13 m2 SHEET 5 OF 5 TORSION CONTACT ZERO-INSERTION FORCE CONNECTOR BACKGROUND OF THE INVENTION Common in the art today are many connectors for receiving the edges printed circuit boards, ceramic substrates, and/or other such circuit boards. These connectors generally fall into one of two types; the contact is forced against the circuitry on the board after insertion of the board or forced away from the board for insertion of the board, then allowed to spring back into contact with circuitry on the board. In both of these examples each contact moves in a generally single-plane cantilever fashion. These movements require space on either side of the circuit board for such contact movement. This space requires a relatively wide connector housing which, in todays high density packaging requirements, is unsuitable. Moreover, the individual contacts require exact spacing tolerances which limits the connector designs to relatively wide contact-to-con tact spacing. Currently 0.050 inch center-to-center is the practical minimum spacing commonly available for non-precision off-the-shelf use.
The most common drawback of the prior art devices is the relatively long distance of insertion of the circuit board to make contact.
BRIEF DESCRIPTION OF THE INVENTION To overcome the above limitations of the prior art applicant has invented a connector wherein the contacts have their contact portions twisted about the elongated axis of the contact. Prior to insertion of a circuit board, which has slots in the edge or contacts connected to the circuitry thereon, the connector contact faces are untwisted, the circuit board is inserted, and the contact faces allowed to twist back toward their position of rest to engage the circuit board contact or slot. In this manner, rather than resting against a surface, the contact faces are restrained within a slot or contact. In this manner misalignment can be compensated for by cantilever bending of the contacts which still allows full torsion action to take place. Moreover, with torsion action, a very small insertion distance is traveled by the circuit board.
It is therefore an object of the invention to provide a connector having a narrow width suitable for high density packaging.
It is another object of the invention to provide a connector wherein precision spacing of contacts on 0.025 inch centers or less is easily attainable.
A still further object of the invention is to provide a connector for zero-force insertion of a circuit board wherein electrical connection is made by the torsion memory of the connector contacts.
Yet another object of the invention is to provide a connector wherein the insertion distance of a circuit board is very small.
Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.
IN THE DRAWINGS FIG. 1 is a partial perspective view of one embodi of the invention with contact faces in position to receive the shown circuit board;
FIG. 2 is a section view taken along line A-A of FIG. 1 showing the contact faces in position to receive the circuit board;
FIG. 3 is a partial section view taken along line A-A of FIG. 1 showing the circuit board in position but prior to release of the contacts;
FIG. 4 is a diagrammatic section view taken along line 8-8 of FIG. 3;
FIG. 5 is a diagrammatic view similar to FIG. 4 but showing the contact in its released position;
FIG. 6 is a section view taken along line C--C showing the contact and actuating bar in position for receiving a circuit board;
FIG. 7 is a sectional view similar to FIG. 6 but showing the contacts in their relaxed position;
FIG. 8 is a perspective view of a second embodiment of the invention showing a double rack actuation with a blade contact;
FIG. 9 is a section view taken along line D-D of FIG. 8 showing a gear and rack actuating mechanism;
FIG. 10 is a partial perspective view similar to FIG. 8 but showing a narrow width contact suitable for mating with the ceramic substrate shown;
FIG. 11 is a partial section view also taken along line F-F of FIG. 8 showing the contacts in their circuit board mating position; and
FIG. 12 is a partial view similar to FIG. 9 but showing the contacts in position for receiving a circuit board.
Looking now at FIG. 1 the first embodiment of the invention is shown. The connector 10 is an elongated box-like structure having flanges 12 with apertures 14 extending from either end for purposes of mounting to a mother circuit board, panel, or the like. The housing has generally upright side walls 16 and end walls 18, horizontal top wall 20 and bottom wall 22.
Located generally centrally between the two side walls 16 is an elongate channel 24 (see also FIGS. 2,3,6, and 7) ending near the top wall 20 in a cavity or recess 26 of a size and shape to receive a printed circuit board 28, or the like. The lower end of channel 24 ends as at surface 30 (FIG. 2) with a plurality of slots 32 extending therefrom to a lower cavity or recess 34. Located within channel 24 are a plurality of contacts 36 of a number equal to the number of slots 32 with each contact having a terminal portion extending into cavity 34 and a con tact portion extending into cavity 26.
The contacts 36 have their elongated axes parallel and aligned in a first longitudinal plane 38. With primary reference to FIGS. 2,3, and 4 each contact 36 is of a wide, flat width relative to its thickness. The contacts are thin enough whereby 0.025 inch center-to'center spacing is easily obtained and 0.010 to 0.015 inch center-to-center spacing is well within design limitations. Each contact is manufactured from a suitable electrically conductive material as is known in the art. Each contact 36 has a terminal portion 40 which in the instant embodiment is a cylindrical barrel suitable for receiving a wire conductor therein to be crimped or suitable for being received by a mating aperture in a mother circuit board or the like. These terminal portions 40 are alternately offset to achieve close spacing of contacts and may take any of several configurations common in the art.
The contact 36, at an intermediate portion 42 (FIG. 1), has cars 44 extending from either side. This portion, with ears 44, is parallel to a first lateral plane. Near the upper end or contact portion 46 a tab 48 extends to the left (F IG. 2). The contact portion comprises an offset two prong fork configuration 48 having a pair of prongs 50 (see also FIGS. 4 and 5) each with a contact face 52.
These contacts have their intermediate portions 42 in slots 32 with the right car 44 (FIG. 2) extending into a notch 54 which prevents vertical movement of the contact. The left ear is located in an elongated channel 56 located in movable wall 58. The tabs 48 are located in individual slots 60 between which are teeth 62. Opposite tab 48 teeth 64 extend one each between the contacts.
The teeth 62 from slots 66 therebetween for receiving the edge of the contact portion. In its position of rest each contact portion 46 including tab 48 is parallel to a second lateral plane which is at an angle both to the first lateral plane and the first longitudinal plane. The two portions lying in different planes is achieved by pre-twisting the contact during the manufacture thereof after which it is placed in the housing. The twisting is confined to the area between portions 42 and 46.
The moveable wall is slidable in the direction of arrows E in FIGS. 6 and 7. As seen also in FIGS. 6 and 7, and FIG. 1, wall 58 is held in alignment by dowel pins 68 or the like which are received in aperture 70 of the connector housing. Wall 58 has an apertured slot 72 at each end for receiving pins 68, the slot allowing for limited sliding movement of wall 58. Also located in the housing through top wall 20 is a rectangular aperture 70 which is aligned with aperture 74 in the bottom wall 22. This aperture 74 need not extend through the wall 22 but need only be a cavity or may not be necessary at all. Offset from aperture 70 in wall 58 is a similar rectangular aperture 76 (FIG. 7). When an appropriately bevel-ended rectangular tool 78 (shown in phantom in FIG. 1 and in FIG. 6) is inserted into aperture 70 and on through aperture 76 the wall 58 is forced to the position of FIG. 6 with teeth 62 causing contact portions 46 to torsion or twist into positions where they are generally parallel to the intermediate portions 42. In this position a circuit board 28 may be inserted into the connector with zero force with each blade contact 80 inserted between offset prongs 50 (FIG. 4). These contacts 80 have fingers 82 suitably connected to respective circuitry on board 24, such as by soldering. After insertion of the board the tool is removed allowing the contact portions 46 to return toward their position of rest causing contact faces 52 to engage blade contacts 80 (FIG.
Turning now to the second embodiment illustrated in FIGS. 8 12 there is shown a connector 84 of a generally elongated box-like configuration having top 86, bottom 88, side 90, and end walls 92 with side walls 90 parallel to a first longitudinal plane. A plurality of contacts 94 are fixedly located in the housing bottom wall 88 with the elongated center lines of the contacts being parallel to and oriented in the afore-mentioned first longitudinal plane (see FIG. 12) which is common with the connectors longitudinal centerline G These contacts extend into a cavity 96 formed by the side and bottom walls. The contacts each have a terminal portion 98 parallel to a first lateral plane and a contact portion 100, which includes laterally extending ears 102 and contact faces 104, and which is parallel to a second lateral plane at an angle to the first longitudinal and first lateral planes. To achieve this construction the contacts are pre-twisted during manufacture prior to placement in the housing.
Located in a channel 106 in each of the side walls and facing the cavity is a rack-type member 108 having slots 110 therein for receiving ears 102. The rack-type members at one end have teeth 112 thereon for engagement with a gear 114. The gear is concentrically carried on a shaft 116 having a slot 118 in the end for receipt of a tool blade (not shown) such as a screw-driver. In the position of FIG. 9 the contacts 94 are in their normal relaxed twisted position. In FIG. 12 the gear 114 and rack-type member 108 are actuated to twist the contact portions 100 to a position of parallelism with the afore-mentioned first lateral plane thus allowing for zero-force insertion of the circuit board 120. Circuit board 120 has edge contacts similar to those of FIGS. I and 4. After insertion of the circuit board the tool is removed and the contacts are allowed to relax as in FIG. 11. The circuit board contacts 122 are engaged by the contact faces 104 and prevent the contact portion from assuming its position of FIG. 9 thus ensuring adequate contact force.
The variation of contact shown in FIG. 10 is a narrower width contact more suitable for engaging the slotted edges 124 of a ceramic substrate 126. Each interior face of slot 124 is a continuation of respective circuitry 128 on the substrate. Blade contact is made similar to that of FIG. 11.
It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it
should be emphasized that the particular embodiments of the invention, which are shown and described herein, are intended as merely illustrative and not as restrictive of the invention.
What is claimed is:
1. A connector for receiving a printed circuit board, ceramic substrate, or the like comprising an elongated box-like structure, a plurality of elongated contacts communicating between a top wall and a bottom wall of said connector, said contacts having their elongated dimension generally aligned along a first longitudinal plane, each said contact being twisted about its elongated dimension, a portion of each contact intermediate the upper and lower ends thereof being generally parallel with a first lateral plane generally nonnal to said first longitudinal plane, contact portions at said upper end of each said contact being parallel with a second lateral plane that is at an angle to said first lateral and first longitudinal planes, movable means engaging said contact near said upper end for imparting torsional movement to said upper end, and actuating means engaging said movable means whereby torsional movement can be imparted to said contact upper end to twist it to a position generally parallel with said first lateral plane.
2. A connector as claimed in claim 1 wherein said movable means includes at least one elongated rack-type member having a plurality of slots in one side thereof, each slot receiving one of said contacts, said rack-type member being slidable in a path parallel to said first longitudinal plane and said first lateral plane.
3. A connector as claimed in claim 2 wherein said contact portions each include plural contact faces, said faces of each contact engaging a single circuit on a circuit board or substrate received by said connector.
4. A connector as set forth in claim 3 wherein said contact portion has a blade-like configuration with opposite sides being contact faces for mating with a slot.
5. A connector as set forth in claim 3 wherein said contact portion has an offset two prong fork configuration with contact faces in parallel ofi'set planes for mating with a blade.
6. A connector as set forth in claim 3 wherein said actuating means includes a gear member in toothed engagement with mating teeth on one end of said rack-type member, said gear member concentrically located on a shaft.
7. A connector as set forth in claim 3 wherein said actuating means includes a first rectangular aperture in said connector housing and an underlapping and misaligned second rectangular aperture in said rack-type member, whereby insertion of a bevel-ended rectangular tool through said first aperture into said second aperture will move the second aperture into alignment with said first aperture thus moving said rack-type member.