Terminal Strip

Abstract

Terminal strip for use in an interconnection system comprises two spaced-apart parallel carrier strips connected together by transversely extending rungs. Contact sockets are integral with the carrier strips on opposite sides of the rungs and extend laterally therefrom. Portions of terminal strip extending between rungs are folded to shorten the pitch of the strip and adapt it for use in housings in which contacts are close together. Strip may be used for feed-through applications, in which the two sockets of each pair are in axial alignment with each other, or for junction blocks in which strip is bent so that the two contacts of each pair extend parallel to each other on each side of the carrier strips.

Description

BACKGROUND OF THE INVENTION

Our previously issued U.S. Pat. No, 3,456,231, for INTERCONNECTION WIRING SYSTEM, discloses and claims a modular-type terminal junction wiring system which is made up of a plurality of similar modules which are mounted in suitable mounting rails or channels. Each module contains a section, or a plurality of sections, or conducting terminal strip having integral contact sockets. Contact pins are inserted into the modules and into the contact sockets on the strip thereby to connect the wires, to which the pins are attached, to each other.

The terminal strip disclosed in the above-identified application, U.S. Pat. No. 3,456,231 comprises a single central carrier strip having, at spaced intervals, contact sockets integral therewith and extending therefrom on its opposite sides. The pitch of this strip, that is, the spacing between adjacent pairs of contact sockets, is shortened by folding the portions of the carrier strip which extend between adjacent pairs of sockets into a keystonelike form. After this folding operation, the contact terminals will be in side-by-side relationship on each side of the carrier strip with the two terminals of each pair being in axial alignment with each other. The strip in this form, that is, with the terminals in axial alignment, is used in feed-through applications. In feed-through applications, wires extending axially towards each other are connected by inserting the contact terminals on their ends into a pair of contact sockets in the modules. The strip in a module may be of any desired length within the accommodating limits of the module to permit common connections among varying numbers of wires. In an alternative embodiment in the invention disclosed in U.S. Pat. No. 3,456,231, the terminals are bent through an angle of 90.degree. so that the two terminals of each pair in side-by-side relationship and extend normally of the original plane of the strip. The strip in this form is used in junction-type block modules to commonly connect two or more wires.

While the terminal strip disclosed in our above-identified application is highly satisfactory under most circumstances, it has been found that where the strip is made from a relatively thick stock metal as is required for relatively large contact sockets, difficulty is encountered in the bending operation and the deformed portions of the strip, that is, the keystonelike formations between adjacent pairs of contact sockets, are relatively bulky, under such circumstances, it is difficult to fit the strip into the individual modules.

The present invention is addressed to the problem of providing an improved form of terminal strip for use in modular interconnection or terminal junction systems of the general type shown and claimed in our above-identified U.S. Pat. No. 3,456,231. It is accordingly an object of the invention to provide an improved terminal strip for use in terminal junction systems. A further object is to provide a terminal strip which can be used in varying lengths to commonly connect varying numbers of conductors in an interconnection or terminal junction system. A still further object is to provide a terminal strip which initially comprises carrier strip means having pairs of aligned sockets extending from opposite sides thereof which can be drastically deformed to locate the contact sockets of each pair in closely spaced side-by-side relationship. A still further object is to provide a continuous terminal strip comprising carrier strip means and contact sockets extending in opposite directions in which adjacent pairs of contact sockets are closely spaced.

These and other objects of the invention are achieved in a preferred embodiment thereof comprising a pair of spaced-apart parallel carrier strips, the adjacent longitudinal ledges of these carrier strips being connected to each other by transversely extending integral rungs. A plurality of pairs of contact sockets are integral with the carrier strip, the two sockets of each pair being in axial alignment with each other and with one of the rungs and extending from the outside edges of the carrier strips. The spacing between adjacent pairs of contact sockets is shortened, after manufacture of the strip by die stamping and forming methods by folding the portions of the carrier strips which extend between adjacent rungs. The contact sockets can be bent, relative to the original plane of the carrier strip, so that they are parallel to, and beside, each other on each side of the carrier strip. The terminal strip can thus be used either for feed through type interconnection applications or for junction block-type applications.

In the drawings:

FIG. 1 is a perspective view of a short section of terminal strip in accordance with the invention and showing, at its left-hand end, the blank from which the contact sockets of the strip are formed;

FIG. 1A is a perspective view of a short section of strip stock material which is used to form the strip of FIG. 1;

FIG. 2A is a perspective view of a section of the strip of FIG. 1 after the pitch of the strip has been shortened by folding the carrier strips;

FIG. 2B is a perspective view of a short section of strip, which has been subjected to a bending operation to position the two contact sockets of each associated pair of sockets in parallel relationship to each other;

FIG. 3 is a perspective exploded view of an interconnection module for feed through applications which utilizes a short section of strip of the type shown in FIG. 2A;

FIG. 4 is a perspective exploded view of a junction block-type module which utilizes a strip of the type shown in FIG. 2B; and

FIG. 5 is a perspective view on an enlarged scale, with parts broken away in the interest of clarity, of a contact socket and illustrating the manner in which a contact pin is inserted into the socket.

A contact strip 2 in accordance with the invention (FIG. 1) comprises a pair of parallel carrier strips 4', 6' which are connected to each other by rungs 8, these rungs extending between, and being integral with, the adjacent edges of the carrier strip. A plurality of pairs of contact sockets 10 are connected to the outside edges of the carrier strips 4', 6' by means of connecting slugs 12 which are integral with the carrier strips on each side of the rungs 8. In FIG. 1, the portions of the carrier strips which extend between adjacent pairs of contact sockets are indicated with primed reference numerals 4', 6' inasmuch as these sections of carrier strips are later folded as shown in FIG. 2A at 4 and 6 to shorten the pitch of the strip, that is, to reduce the spacing between adjacent pairs of contact sockets.

The strip 2 of FIG. 1 is formed from laminated stock material as shown in FIG. 1A comprising a lower layer 14 of a suitable high strength sheet metal having good spring properties such as beryllium copper and a relatively thicker layer 16 of metal having good conducting properties such as electrolytic copper. The high strength material 14 extends laterally beyond the edges of the high conductivity material 16. Beryllium copper is a particularly suitable material for the layer 14 for the reason that it is age hardenable. The strip can thus be stamped and formed when this strip is soft and can be heat-treated to develop spring characteristics in the layer 14. The sockets 10 are formed from generally rectangular blanks 10', the lower layers (as viewed in FIG. 1) 18' of these blanks ultimately forming the outer cylindrical tubelike members 18 of the individual sockets. In addition, a strip 20' of copper (formed from layer 16) is located along the inner side of each blank such that after forming of the sockets, this strip forms a cylindrical liner 20 (FIG. 5). The liner 20 is integral with the copper layer portion of the finished terminal strip which extends across the neck portions 12 and along the carrier strip portions 4, 6, to the next adjacent pairs of sockets and provides a conducting path in the strip of low electrical resistance.

A pair of lances 22 are provided on opposite sides of each socket which function as retainer springs in a manner described below and a single contact spring 24 is provided between these lances which functions to bias an inserted contact pin 26 against the conducting liner 20 of the socket. As shown in FIG. 1, these lances and the contact spring are formed by struckout portions 22', 24' in the flat blanks 10' from which the sockets are formed.

Sockets of the type shown in the drawing are adapted to be used with cylindrical contact terminals 26 which are crimped as shown at 30 onto the ends of the wires 32. The forward cylindrical portions 28, of the sockets are provided with a circumferential collar 34 and the forward end 36 of each pin functions as a contact portion which, after insertion, bears against the inner surface of the liner 20 of the socket. After insertion of an individual contact pin 26 into a socket, the ends of the lances 22 lodge against the leftwardly facing surface 38 of the collar 34 thereby to lock the contact in the socket. The contact spring 24 bears against the surface of the collar 34 and maintains the contact surface 36 in engagement with the surface of the liner 20. These features of the contact pins and sockets are described more fully in the above-identified U.S. Pat. No. 3,456,231.

FIG. 1 shows the terminal strip as it comes from the stamping and forming die. Prior to use of the strip, the portions 4', 5' of the carrier strip which extend between adjacent rungs 8 are folded as shown in FIG. 2A thereby to substantially reduce the pitch of the strip. The strip shown in FIG. 2A is used in modules of the type shown in FIG. 3, each of these modules comprising a pair of identical insulating housings 40a, 40b in which there are mounted resilient insulating inserts 42 of neoprene rubber or similar material. Contact receiving cavities 43 extend through these inserts and through a block 44 secured to the housing blocks 40a, 40b. The openings 46 being in axial alignment with the cavities 43 of the inserts 42. During assembly of the module of FIG. 3, the desired length of contact strip 2 is positioned between a pair of housings 40a, 40b and the contact sockets of the strip are inserted into corresponding contact receiving cavities 43 of the housings. The two housings are then moved relatively towards each other and cemented or otherwise secured together. The folded portions 4, 6 of the carrier strip will bear against and compress the surface portions 45 of the resiliently deformable inserts 42 of the housings as explained more fully in our above-identified pending application. It will be understood that in FIG. 3, a section of strip will also be positioned in the cavities 43 which appear at the left in these housings and that these sections of strips have been omitted from the drawing in the interest of clarity.

Junction block-type modules (FIG. 4) are produced by bending the rung portions 8 of the carrier strip 2 along bending lines at 56 extending parallel to the longitudinal axis of the strip and on each side of the centerline thereof. After such bending of the strip, the contact sockets will be in parallel side-by-side relationship as shown in FIG. 2B and the folded portions 4, 6 of the strip, will extend laterally outwardly and between adjacent pairs of contact sockets. As shown best in FIG. 4, a junction-type module is made up of a housing block 40 as previously described having a resilient insert 50 therein. The insert 50 differs from the previously described insert 42 in that it is provided with a generally oval-shaped openings 52 adapted to receive a pair of cooperating contact sockets. Each opening 52 is in alignment with a pair of contact receiving cavities which extend through through the insert and through the block 44 and open into the upper surface of the block as shown in FIG. 3. Again, details of junction-type modules of this type are described fully in are previously identified U.S. Pat. No. 3,456,231. After insertion of the terminal strip in FIG. 4, a cover plate 54 is secured against the surface of the block 40 and cemented or otherwise secured thereto. Again, the folded portions of the carrier strips 4, 6 bear against the insert 50 at 58 between adjacent openings 52 in the insert 50 and compress it.

The junction module shown in FIG. 4 adapted to receive 10 individual contact pins to commonly connect 10 electrical conductors. If common connections are desired among a lesser number of conductors, for example, two, four, six, or eight, shorter sections of terminal strip are used and folded portions of the carrier strips are removed and discarded.

A salient advantage of the terminal strip in accordance with the invention is that the folded sections 4, 6 can be formed even if the strip is manufactured from a relatively thick stock material. These folder portions of the carrier strip will moreover be relatively stiff and maintain the contact sockets of adjacent pairs in accurate spaced relationship to each other. The carrier strip can be sent as shown in FIG. 2B with relative ease to form strip material for junction-type modules. When strip of this type is inserted into a module as illustrated in FIG. 4, the material between adjacent openings 52 in the insert 50 is compressed by the bight portions of the carrier strips. Thus, only a short length of the carrier strips bears against the insert 52 and assembly of the terminal strip to a module is a relatively simple operation.

It will be apparent that the folding of the strip will not always be required in the practice of the invention. Under some circumstances, it might be found that the contact terminals will be spaced apart by the required amount without folding the strip. Where the contact terminals take the form of sockets, as in the disclosed embodiment, the spacing between adjacent terminals will be determined by the developed width of the sockets, that is, the width of the blank 18' in FIG. 1, and this dimension will be relatively large for the larger sizes of the sockets.

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.

Claims

What we claim is:

1. A terminal strip adapted for use in an interconnection wiring system comprising, a pair of parallel spaced-apart carrier strips, said strips being connected to each other by spaced-apart transversely extending rungs, a plurality of pairs of contact terminals, the two terminals of each pair being integral with said carrier strips on opposite sides of rungs, said strips being foldable between said rungs to shorten the pitch of said strip and said carrier strips being bendable relative to said rungs to position the two terminals of each pair in side-by-side parallel relationship, said strip being formed from laminated metal stock, said strip having a first layer of highly conductive metal extending over said carrier strips, over said rungs, and partially over said contact terminals and having a second layer of high strength metal against said first layer and extending laterally beyond said first layer on each side of said strip, said contact terminals comprising, at their extremities, said second layer.

2. A terminal strip as set forth in claim 1 wherein said contact terminals comprise contact sockets.

3. A terminal strip as set forth in claim 1 wherein said contact terminals comprise contact sockets, said second layer comprising the free end portions of said sockets, said first layer forming a liner in said contact sockets and providing a low resistance conducting path in said strip.

4. A strip as set forth in claim 3 wherein said end portions of said sockets have integral contact spring means therein formed from said second layer, said contact springs means being effective to maintain an inserted contact pin in engagement with the surface of said liner.

5. A strip as set forth in claim 3 wherein said end portions of said sockets have integral retainer springs therein formed from said second layer, said retainer springs being effective to retain inserted pins in said sockets.

6. A terminal strip adapted for use in an interconnection wiring system comprising, a pair of parallel spaced-apart carrier strips, said strips being connected to each other by spaced-apart transversely extending rungs, a plurality of pairs of contact terminals, the two terminals of each pair being integral with said carrier strips on opposite sides of said rungs, the portions of said strips between said rungs being folded thereby to reduce the pitch of said strip.

7. A terminal strip as set forth in claim 6 wherein said carrier strips are bent relative to said rungs and lie in parallel planes extending normally of the plane defined by said rungs, the two contact terminals of each pair being in side-by-side parallel relationship with their axes extending normally of said plane defined by said rungs.

8. A terminal strip comprising a continuous carrier strip having a plurality of contact terminals integral with and extending laterally therefrom, said contact terminals having contact surface portions disposed adjacent to said carrier strip, said strip being formed from laminated stock metal comprising a high strength layer and a highly conductive layer, said highly conductive layer extending along said carrier strip and partially onto said contact terminals, said highly conductive layer constituting said contact surface portions of said terminals, said highly conductive layer extending laterally beyond said highly conductive layer and constituting the end portions of said contact terminals.

9. A strip of contact terminals for use in an interconnection system, said strip comprising a central carrier strip, a plurality of pairs of contact terminals integral with said carrier strip, the two contacts of each pair extending laterally of said strip in opposite directions and being in axial alignment with each other, said contact terminals being integral with said carrier strip by means of connecting slugs having a length sufficient to permit said contacts to be bent relative to said strip until the axes of said contacts extend parallel to each other and normally of said strip, each of said terminals comprising a contact socket adapted to receive a contact pin, said strip being of laminated metal comprising a first lamina having a high electrical conductivity and a second lamina of high strength springy material, said first lamina extending over said carrier strip and partially into said sockets and said second lamina extending laterally beyond said first lamina, the portions of said sockets which are remote from said carrier strip being formed of said second lamina.

10. A strip as set forth in claim 9 wherein each of said sockets has a contact spring and a retainer spring struck from its wall, said contact and retainer springs being of said second lamina and extending towards said carrier strip.

11. A strip of contact terminals for use in an interconnection system, said strip comprising central carrier strip means having a plurality of pairs of contact terminals integral therewith, the terminals of each pair being disposed on opposite sides of said strip means said strip means being in a shortened condition as a result of folding parallel to its length at periodic intervals whereby said terminals on each side of said strip means are spaced apart by a distance which is less than the developed width of said terminals as measured along the length of said carrier strip means, said terminals being bent, relative to said strip and extending normally of the plane of said strip.