US3796986A - Interconnection system for reusable gang-type connections between flexible printed circuitry and the like - Google Patents

Abstract

Connections to flexible printed wiring elements and rigid printed circuit board elements are effected by the disclosed interconnection system consisting essentially of a pressure contact type connector block and backing element. Various shapes of pin connectors are disclosed. Add-on features include feedthrough elements, and a variant of backing element in which removable pressure contact wire-wrap terminal elements may be inserted. Non-noble metal, low pressure contact elements are usable.

Description

United States Patent Tamburro 1' Mar. 12, 1974 [54] INTERCONNECTION SYSTEM FOR 3,102,767 9/1963 Schneck 339/176 MF U BL GANG.TYPE CONNECTIONS 3,372,308 3/1968 Norschese et al. 339/17 LM 3,550,062 l2/l97O Drenten et al 339/17 LM BETWEEN FLEXIBLE PRINTED 3,613,049 10/1971 Niedzwiecki 339/176- MF CIRCUITRY AND THE LIKE Inventor: Peter James Tamburro, Morris Plains, NJ.

Assignee: Bell Telephone Laboratories,

Incorporated, Murray Hill, NJ.

Filed: July 3, 1972 Appl. No.: 268,725

Field of Search 339/17, 92, 176, 278

References Cited UNITED STATES PATENTS Rice et a] 339/17 LM I Primary ExaminerJoseph H. McGlynn Attorney, Agent, or Firm-C. E. Graves [5 7] ABSTRACT 3 Claims, 15 Drawing Figures PAIENIEBIAR 1 2 1974 sum 1 ur 5 FIG.

PATENTEUHAR 1 2 m4 3796386 SHEEI 2 OF 5 FIG. 3

PATENTEUHARIZ m4 3796586 SHEEI & 0F 5 FIG. 8

PAIENTEDNAR 12 1924 I 3796 986 sum 5 0F 5 FIG. 3A

INTERCONNECTION SYSTEM FOR REUSABLE GANG-TYPE CONNECTIONS BETWEEN FLEXIBLE PRINTED CIRCUITRY AND THE LIKE FIELD OF THE INVENTION This invention relates to electrical multiconn'ection technology and in particular to connections made with so-called flexible printed wiring or the like.

BACKGROUND OF THE INVENTION As is well known, the main attractiveness of flexible printed wiring (FPW) is in reduced labor costs. Numerous FPW configurations and associated contact structures presently exist or have been proposed. One type ofstructure is a double-sided FPW member having so]- der-fastened through-pins. The double-sided FPW may have other layers of circuitry between the outer layers, thus becoming increasingly inflexible as the number of layers increase. At some point the FPW becomes mechanically equivalent to a hard printed wiring board (PWB).

Many pressure-type connectors are available which rely upon a force contact between a land and a contact element to achieve reliable electrical connection. There are, however, several problems associated with the force-contact pressure connector. For one, it is usually required that both the contact element and the land area be gold-protected because-unlike all other contact metalsgold does not form an oxide coating. Hence, use of gold avoids the condition of contact resistance which other metals in time develop, and which renders the connector unreusable or inferior even if the connection is never distrubed.

Gold-plated contacts are, however, expensive and, if only for this reason, ample incentive exists to devise a satisfactory non-noble metal contacting scheme.

A further problem with present FPW connections is the lack of a standard and versatile system that with relatively few modules, will accommodate rigid boards and FPW elements alike, will permit cross-over interconnections, will provide for wire-wrap terminal connections, and will enable unlimited feed-through from one FPW to another.

This invention is addressed to the general solution of the last-named problem, and takes for its several further inventive objects the following:

to reduce the cost of back-plane wiring;

to enhance the reliability of inexpensive electrical gang-type contacts for use with FPW elements;

to achieve a solder-to-solder contact between FPW apparatus and a solid connector; and

to provide all of the foregoing in a specific design of connector element featuring reusable as well as removable contacts.

SUMMARY OF THE INVENTION In its broadest aspect, this invention is a gangconnector system comprising a body for mounting of a linear array of contacting pins. The pins are phosphorbronze or beryllium-copper solder-plated to a thickness of about 0.0003 to 0.0005 on that portion which contacts the FPW. A chamber for receiving the end contacts of an FPW element is provided in one side of the body. Into this chamber each pin extends. The opposite face of the connector body is flat, and each pin is looped through the body to lie in planar array a predetermined distance above this flat surface. These ends of the pins are to join to a land area of the FPW or flexible flat cable member, and accordingly are normally disposed slightly above a recessed part of the body.

A feature of the invention is pressure-type contacts using non-noble metals to achieve connection between two elements such as a rigid circuit board and a flexible printed cable.

A further feature of the invention in combination.

with the first-mentioned feature, is the use of single tapes with printed circuitry on one or both sides interconnected vertically and horizontally by the disclosed system, and stacked toform a truly flexible multiple layer circuit.

The invention and its further objects, features, and advantages will be readily understood from a reading of the description to follow of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic perspective view showing the basic connector block; I

FIG. 1A is a type of contact for FIG. 1, perspective view;

FIG. 1B is a sectional side view of the connector block of FIG. 1.

FIG. 2 is an exploded schematic perspective diagram of the connector block of FIG. 1 together with a feedthrough block and a backup block;

FIG. 3 is a variation of the FIG. 1 embodiment in which terminals in the connector blocks are supplied with wire-wrap extensions and the flexible tape is perforated to receive the extensions;

FIG. 3A is a type of contact for use in the FIG. 3 embodiment;

FIG. 4 is a variant demonstrating a further system involving the FIG. 1 connector block, useful to interconnect horizontal and vertical FPW members; and further showing use of removable pressure contacts on a backing block; I I

FIG. 5 is a schematic perspective diagram illustrating multiple use of feed-through blocks to interconnect multilayer boards to an F PW element via the connector block;

FIG. 6 is a two-sided FPW with plural pairs of connector blocks connecting thereto, one member of each seen in side pair per side; and further shows various further interconnect capabilities;

FIG. 7 is a side schematic diagram illustrating use of the FIG. 1 connector block and backup plate to interconnect a rigid PCB to an FPW.

FIG. 8 illustrates two connector blocks of FIG. 1 used in back-to-back fashion in the manner of FIG. 6;

FIG. 9 is a side schematic perspective of several multilayer FPW elements interleaved and perforated to enable remote interior contacts through a pressure contacting element of the connector block;

FIG. 10 illustrates in sectional side schematic diagram a double-connector block and the associated pin element;

FIG. 11 illustrates in similar fashion a double-feedthrough type block; and

FIG. 12 is a side schematic perspective view of contact element of FIG. 10.

In the description to follow, emphasis will be periodically placed on the systems aspects of the interconnection scheme, its flexibilities and add-on features made possible by the overall inventive concept. Where necessary, details of the structural elements involved will be amply set forth; but elsewhere, only so much structural detail as necessary to practice the invention will be supplied.

The basic connector block is shown in FIGS. 1, 2, 8, in detail. The block designated generally consists of an inner cavity 1 1, which includes a bottoming floor 25 and a number of dividing wells 12 rising from floor 25 and terminating in the plane of the top edge of block 10. The walls are about one-half the width of the cavity 1 l, and form a plurality of wells 15, which receive connector pins such as pin 20 illustrated in FIG. 1A. Numerous shapes of pins may be placed in the wells 15 of connector block 10 as will be shown in illustrations to follow. All pins are, however, pressure-type contact members.

In FIG. 1 the FPW element, or tape 16, is not supplied with through holes. In consequence, the entirety of both sides of tape 16 may be used for circuit paths. Holes are not needed in this case except for the occasional interconnection between sides. The sectional side view of the connector block is shown in FIG. 1B. In FIG. 3, however, the tape 16' is provided with through-holes in between the land regions 16a. The connector block 10 is substantially the same as that shown in FIG. 1 except that the pin element designated 40 shown in FIG. 3A includes extension 41 which serves as a wire-wrap terminal when such is desired. The pins 40 shown in place in connector block 10 in FIG. 3 need not, of course, be situated in every position; but may be selectively placed where needed. Those pins 40 which are in place are insertable through the holes 16b in tape 16'. To complete the assembly, a backup block 39 similar to block 19 but with holes therein is supplied to accommodate the terminals 41. FIG. 3 thus depicts an embodiment of the invention which receives an FPW tape 16', contacts where necessary its land regions 16a with a cantilevered pad 38 of the pins 40. Then, the same assembly receives a plug-in board 52 which is inserted into the inner cavity 11, shown in FIG, 1, where the board contacting belly 23a of the pin 40 makes contact with extensions of the land areas 32a.

The embodiment of FIG. 4 illustrates the use of a feed-through block 32 which in combination with the pin and a somewhat modified backing block 49 will permit connection of a horizontal FPW 42 to a vertical" FPW 43. Further, the assemblage of FIG. 4 illustrates use of a removable pressure contact element 44,

consisting of an upstanding wire-wrap terminal portion 45, a spring-contact pad 46, and a pair of guide arms 47 with locking ears. Corridors 48 in the backing block 49 each with guide slot pairs are provided to receive the locking ears of guide arms 47.

Thus, the assemblage of FIG. 4 provides capability of receiving a printed wiring board in the connector block 20 in the manner shown in FIG. 3; of receiving and interconnecting also a pair-of flexible printed wiring elements using the feed-through block 32; and then by use of removable pressure contacts provides further capability for interconnection.

The feed-through member 32 is depicted also in FIG. 2 as consisting of a plurality of three-sided hollow-outs 28 in which are inserted connector pin elements 29 which are also three-sided. The elements 29 are contained wholly within the hollowouts, except for the contact surface bulge 29a which occurs twice on each element on opposite sides thereof. Illustrated in FIG. 2 also is a guide flange 26 on the connector block 10 bottom, which engages a locating well 30 in the feed through block 32. In turn, a guide flange 27 on block 32 engages a locating well 30a in the backup block. A threaded pin 33 and nut 34 are the fastening'means for the already axially coordinated assemblage of FIG. 2. The guide flanges also may be used to polarize, that is, fixedly orient, the connector assembly and system assembly with flexible and hard printed boards.

With reference again to FIG. 4, the FPW elements 42, 43 are supplied with lands 35, 36 respectively. Lands 35 are contacted by pressure pad ends of modifled connector pins 20a. The pins 20a are the same as those shown in FIG. 1A and designated '20, except that the ends are cantilevered upward and extend out beyond the connector block body so as to effect springloaded connection to a horizontal FPW such as 42in contrast to the connector pins depicted in FIG. 8 which feature the stationary ears 21 embedded below and within the connector block body.

The lands 36 of FPW 43 are contacted by the spring- I contact elements 46 of the removable pressure contact 44. An interference fit provided between the arms 47 and the guide-slot pairs 50 supply adequate holding force'to maintain position. As in the embodiment of FIG. 3, the upstanding terminal portion 45 of the contact 44 is for wire-wrap connection where needed.

In a further variation of the inventive interconnection system, as seen in FIG. 5, a capability for interconnecting a plurality of multilayer rigid boards is provided by use of the backup block 19 or 49, as many feed-through members 32 as necessary and by connector block 10;

The operation of this configuration is much the same as already described-with respect to the interconnection of several FPW members depicted in FIG. 4. The land areas on the several rigid boards 37 are not shown; but it is seen that connection to lands are effected by the mechanisms already shown in FIG. 4. Similarly, by using a backup member such as 49, removable pressure contacts can be added to the configuration; and the inner cavity 11 of connector block 10 supplies the already described capability of receiving yet another rigid board. I

With respect again to the FIG. 5 embodiment, flexible printed wiring elements (not shown) could be used in place of any or all of the rigid boards 37. Using the add-on capabilities of a backup block 49 with a plug-in board (not shown), for connector block 20 in the assemblage of FIG. 4, it is possible. to interconnect any two circuit paths on either of the F PW elements 42, 43;,

and also to establish one or more connections from any or all of the lands of F PW elements 42, 43 to the outside world.

FIG. 6 shows a further embodiment of the invention in which a plurality of pairs of connector blocks 10 are placed back-to-back on opposite sides of a two-sided PWB tape designated 16. A desirable characteristic of g the spacing of the pins 20 of block 10 is that the spacing element 60 along the same lateral plane; thus, two back-to-back connector blocks such as blocks a,

10b, can be located and fastened together as already described. Then, a second FPW element 62 can be used to interconnect selected ones of land areas 61 by connection of the opposite ends of element 62 into the connection cavities 11 of the connector blocks 10a and 10c. Additionally, the connection cavities ll of the remaining paired connector blocks depicted in FIG. 6 receive plug-in cards or other kinds of already described connection devices. Circuit packs a, b, and c, of FIG. 6 are examples of such plug-in devices.

Although not shown in FIG. 6, it should be apparent that feed-though blocks such as 32 illustrated in FIG. 4 can also be used with respect to this assemblage, to the same advantage as already described with respect to FIG. 4. Likewise, a backup block such as 19 or 39 or 49, all already described, may be used in place of or in addition to any one of the connector blocks depicted in FIG. 6again in the manner and to the advantage already described.

In a further inventive embodiment depicted in FIG. 7, a rigid printed circuit board 51 may be interconnected with an FPW element 52 by use ofa pair of connector blocks 10 with associated backup blocks 19 and use of feed-through blocks 32. FIG. 7 is intended to illustrate that the interconnection system of the present invention supplies circuit connections between rigid and flexible elements quite simply. The embodiment of FIG. 7 further demonstrates that flexible printed wiring will allow for more manufacturing tolerances than a hard board with fixed locating holes.

In a variation of the use of thebackup block 39 with its removable pressure contacts 44, FIG. 9 depicts a multilayer FPW 55 which has top, middle'and bottom layers 56, 57, 58 respectively. Here, the objective is to make contact to a lower level such as FPW 57. To this end, windows such as 59 are placed between the circuit paths 63 of layer 56, so as to reveal the paths 64 of layer 57 in offset relation with respect to the path 63 of element 56. Then, a pressure contact such as element 44 held in a backup block (not shown) are oriented to protrude through the windows 59 and effect a pressure contact with the paths 64. The windows 59 can occur in recurrent rows along the top layer 56, as shown. This may also be accomplished by any of the contacts in blocks 10, 70 provided there are windows in the printed circuit elements to accept the contacts.

As has already been discussed, a large number of different pin configurations can be envisioned in the general connection system described.

FIG. 10 depicts a double connector block designated 70, which differs from block 10 by its use of two opposing pins 71 in each well 72a and 72b. The wells are opposing and are achieved by opposite rows-of dividers Pin 71 is depicted specifically in FIG. 12 and consists of a heavy central portion 74, anoffset arm 75, and a bow 76 of reduced width. Bow 76 includes a length whose face 77 is rounded to supply a pressure point for interconnection circuitry. The opposite end of central portion 74 supports a pair of contact points 78 formed by an outwardly extending zone of the central region. A slot 79 separates the contact points 78. The arms 80 on which the contact points are built are supported by a spring member 81 from its top portion. The bottom FIG. 11 depicts a double-feed-through block designated which performs the same function as feedthrough block 32, but achieves the feed-through with two separate pin elements for each of numerous longitudinal points along the block 90. The pin elements 91 are generally shaped like a W with a flat 92 separating the central region. It is seen that such a double-feedthrough block as depicted in FIG. 11 supplies the added advantage of increased density of contact and cross-connect points.

It is to be understood that the embodiments described herein are merely illustrative of the principles of the invention. Various modifications may be made thereto by persons skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A system for making electrical connection to circuit paths contained on at least one side of a flexible tape, comprising:

a connector block comprising:

an interior cavity defined between two elongate closely spaced walls, said cavity having a bottoming floor, plural ribs rising from said floor, each being attached along one of said elongate walls, each rib terminating at a plane substantially half-way to said other elongate wall, adjacent ones of said ribs defining plural pin containers, said block further comprising a sunken flat exterior .surface on the side opposite said interior cavity, said bottoming floor having passages through to a central zone of said flat exterior surface, one said passage occurring between each pair of adjacent ribs; and

a pin element lockably disposed in each said container, each said pin comprising:

a first section extending through said passage and terminating in a spring-loadable cantilevered tapecontacting pad that in the unloaded state extends beyond said sunken surface, said pad being formed by a bow in the cantilevered region formed inwardly of the bitter end of said first section said pin element further comprising a second section housed in each said container and including a spring-loadable midportion that in the unloaded state extends beyond the terminal plane of said ribs,

each saidpad being adapted to pressure-contact a selected circuit path of a flexible tape placed on said sunken flat exterior surface of said connector block and each said midportionbeing adapted to pressure-contact a selected circuit path of an electrical insert element placed in said block interior cavity;

backup block means substantially coextensive in length with said connector block means and comprising a pressure application surface for contacting said tape; and

means for pressably engaging said backup block means and said connector block means to force said tape against 'said pin element pads thereby to spring-load said pad onto said tape.

2. Apparatus pursuant to claim 1, wherein:

each said pin element further comprises an elongate terminal extending through the respective said passage and out substantially beyond said sunken surface at an attitude normal thereto and generally at right angles to said pins said cantilevered pad, said flexible tape including holes for passably receiving I said elongate terminals; and

wherein said backup block further comprises a like number and spacing of holes also for passably receiving said elongate terminals, each said elongate terminal adapted to receive a wire connection on the region exposed beyond s'aid backup block means. 3. Apparatus pursuant toclaim 2, further comprising:

ble tape thereinbetween.

Claims (3)

1. A system for making electrical connection to circuit paths contained on at least one side of a flexible tape, comprising: a connector block comprising: an interior cavity defined between two elongate closely spaced walls, said cavity having a bottoming floor, plural ribs rising from said floor, each being attached along one of said elongate walls, each rib terminating at a plane substantially half-way to said other elongate wall, adjacent ones of said ribs defining plural pin containers, said block further comprising a sunken flat exterior surface on the side opposite said interior cavity, said bottoming floor having passages through to a central zone of said flat exterior surface, one said passage occurring between each pair of adjacent ribs; and a pin element lockably disposed in each said container, each said pin comprising: a first section extending through said passage and terminating in a spring-loadable cantilevered tape-contacting pad that in the unloaded state extends beyond said sunken surface, said pad being formed by a bow in the cantilevered region formed inwardly of the bitter end of said first section said pin element further comprising a second section Housed in each said container and including a spring-loadable midportion that in the unloaded state extends beyond the terminal plane of said ribs, each said pad being adapted to pressure-contact a selected circuit path of a flexible tape placed on said sunken flat exterior surface of said connector block and each said midportion being adapted to pressure-contact a selected circuit path of an electrical insert element placed in said block interior cavity; backup block means substantially coextensive in length with said connector block means and comprising a pressure application surface for contacting said tape; and means for pressably engaging said backup block means and said connector block means to force said tape against said pin element pads thereby to spring-load said pad onto said tape.

2. Apparatus pursuant to claim 1, wherein: each said pin element further comprises an elongate terminal extending through the respective said passage and out substantially beyond said sunken surface at an attitude normal thereto and generally at right angles to said pin''s said cantilevered pad, said flexible tape including holes for passably receiving said elongate terminals; and wherein said backup block further comprises a like number and spacing of holes also for passably receiving said elongate terminals, each said elongate terminal adapted to receive a wire connection on the region exposed beyond said backup block means.

3. Apparatus pursuant to claim 2, further comprising: feed-through block means substantially coextensive in length with said connector block means and comprising plural three-sided hollowout regions spaced in corresponding relation to said spring-loadable contacting pads, three-sided metallic pin connector means disposed within each said hollowout region and including first and second spring-loadable ends, each said end including a midportion that in the unloaded state extends out and beyond the hollowout regions, and means for positioning said feed-through block means upon said connector block means with a first flexible tape thereinbetween.

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