US3155809A

US3155809A - Means and techniques for making electrical connections

Info

Publication number: US3155809A
Application number: US361490A
Authority: US
Inventors: Lee M Griswold
Original assignee: Digital Sensors Inc
Current assignee: Digital Sensors Inc
Priority date: 1964-04-21
Filing date: 1964-04-21
Publication date: 1964-11-03
Anticipated expiration: 1981-11-03

Description

Nov. 3, 1964 L. M. GRISWOLD MEANS AND TECHNIQUES FOR MAKING ELECTRICAL CONNECTIONS Filed April 2l, 1964 Mlllumulummw M6. Z. m20

INVENTOR. 5E/1J. 65?/5 WO two ribbon-type cables.

United gStates Patent Ollice 3de-@99 MEANS AND TECHNlQUES FR MAKING ELECTRECAL CQNNECHNS Lee M. -riswold, Pasadena, Calif., assigner to Digital Sensors Inc., Los Angeles, Calif., a corporation of California Filed Apr. 21, i964, Ser. No. 361,490 9 Claims. (Cl. 219-86) The present invention relates generally to a method and apparatus for making an electrical connection to a conductor embedded in insulating material and is particularly useful for making electrical connections to a flexible ribbon-type cable in which the body of the ribbon is a plastic insulating material and parallel-spaced, thin ribbon-type conductors are spaced and embedded in the plastic ribbon. l

The present 'application is a`continuationinpart of -rny copendin'g application Serial No. 176,729, tiled March l, 1962, now abandoned.

Briefly, the arrangement as described herein involves the use of a pair of heated electrodes between which the parts to be electrically connected are disposed. One of such parts is a ribbon-type cable as described above and the other part may, for example, be a similar ribbontype cable or an insulated or an uninsulated wire or terminal pin. The parts .to be electrically connected are squeezed together by the heated electrodes, forcing themselves through the insulation 'by heat softening and owing or crowding of the insulation until those metal parts that are ultimately .to be electrically connected are in physical Contact, after which a welding current is passed between the electrodes and parts to spot-weld or resistance-weld such parts together in a permanent electrical connection. The welding current may be initiated either in accordance with a signal developed when the parts are in metallic Contact or when the pressure betweenl the electrodes exceeds a predetermined amount.

It is therefore an object of the present invention to provide new means and techniques for accomplishing the above-described operations and results.

A specific object of the present invention is `to provide improved means and techniques for making electrical connections to a flexible ribbon-type cable.

Another specific object of the present invention is to provide improved means and techniques for selectively connecting diferent `conductors of different ribbon-type cables together in a permanent electrical connection without appreciably increasing the overall thickness of the Another specific object of the present invention is to provide improved means and techniques for making terminal connections to conductors of a. flexible ribbon-type cable.

The features ofthe present invention whichv are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken connection with the accompanying drawings in which:

FIG. 1 is a top plan view of two ribbon-type cables which are electrically interconnected in accordance with features of the present invention.

FIG. 2 illustrates the apparatus for producing the connection illustrated in FIG. l.

FIG. 3 is an enlarged view of a portion of the two ribbomtype cables illustrated in FIG. l.

FIG. 4 .is a view similar to FIG. 3 and exemplifies other types of connections between the two ribbon-type cables.

tresses Patented Nov. 3, 1964 FIG. 5 is a sectional view generally as indicated by the line 5J-5 in FIG. 4 prior, however, to commencement of the operation performed by the apparatus shown in FIG. 2.

FlG'. 6 is a view like FlG. 5 and serves to illustrate the completion of one electrical connection and also the position of the electrodes at the time the welding current is passed therethrough for bonding adjacent conductors in adjacent cables.

FIG. 7 is a perspective view illustrating one step in the process of connecting a connector pin or tap or wire or solder pin to a conductor of a ribbon-type cable.

FiG. 8 is a perspective View for purposes of illustrating another method and the resulting terminal construction.

The ribbon-type cables referred to herein are commercially available and, as illustrated in FlG. l, comprise an assembly of spaced thin ribbon-type copper conductors l@ embedded in a thin ribbon-shaped plastic ll which may be of polyethylene, a polyester or Mylar. Such insulating material may either be a thermoplastic resin or a thermosetting resin. A like ribbon-type cable, to which electrical connections are made, is illustrated as having conductors 2d and insulating material 2l, and the latter ribbon-type cable, as sho-wn in FIG. l, has four connector pins or solder pins connected thereto using the method illustrated in FIG. 7.

FIG. l illustrates two electrical connections between the two cables, such connections being illustrated at 39 and Si, and such connections are made as now described in connection with FIG. 2.

In FlG. 2, there is provided heated spot-welding type electrodes ed and 41 between which the ribbon-type cables are disposed. The electrodes lit and il are in the form of pointed rods and are each bolted in heat-conductive relationship to a relatively heavy massive metal bar l2 and 43, respectively, such bars being in heatconductive relationship with corresponding electric heaters stand 45 supplied with heating current through the heater wires illustrated. The lower electrode il is preferably maintained stationary and `serves in the nature of an anvil, while the upper electrode ttl is movable for compressing the adjacent tape sections together in the manner illustrated in FIGS. 5 'and 6. FIG. 5 illustrates the initial position of the electrodes dll and 4l, and FIG. 6 illustrates their nal position wherein the electrodes 40 and fil are in electrical Contact with corresponding conductors in corresponding cables.

It will be seen that FIGS. 4, 5 and 6 have reference to a vditferent arrangement of connections between the conductors of the four-conductor cable 2li, 2l and the sevenconductor cable lil, Il for purposes of demonstrating the versatility of the invention and in such case there are four

electrical connections

32, 33, 34 and 35. Two of the conductors lll, as illustrated, are interrupted as, for example, by piercing or shearing portions out of the tape lll, 11. The interrupted ends of one of the conductors Ill, as illustrated in FIG. 4, are connected at 32 and 33 to different conductors 2G; and likewise, the interrupted ends of a different conductor lil are connected at 34 and 35 to other conductors Ztl.

During the application of pressure between the electrodes 40 and di, heat is transferred from such electrodes lil and 4l to the insulation ll. and 21 to soften and crowd such insulation out of the path of the advancing electrodes 4b and 4l and also to soften and crowd the insulation between conductors It? and 2t) until ultimately there is a metal-to-metal contact between electrode 4G and conductor lt), and also a metal-to-metal contact between electrode lll and conductor 20, and also a metalto-metal contact between the conductors 1t) and 2li. When this condition is achieved, a welding current is caused to flow through this series electrical circuit decasacca .es scribed from source i) which has one of its terminals connected to the electrode lll and the other one of its terminals connected to the electrode 4l. Such welding current is caused to flow automatically when the abovementioned condition is achieved, using eitheroue of two techniques now described. As illustrated in FIG. 2, there is provided a pressure-sensitive switch 5l having its actuating element in the path of movement of the movable electrode structure 4d, d2, ld so as to be actuated thereby when the force or pressure applied to such moving electrode structure exceeds a predetermined amount, in which case the switch 5l is closed to fully energize the source 5d and to produce the above-described ilow of welding current between electrodes lil and lil. For purposes of illustration, such switch 5l is illustrated as being actuateble by the extension 425A of plate 42. A source of welding current so controlled may be, for example, of the type made under the name Weldmatic by Unitek Corporation of Monrovia, California.

An alternative arrangement for initiating the flow of welding current involves an electric sensing circuit which is closed when the condition illustrated in FIG. 6 is established, whereupon such sensing circuit is operative to produce full energization of the welding current source Si? and resulting flow of welding current between electrodes dll and 4l.

The technique is also applicable to welding connector pins or soldering pins E@ to the ends of the four-conductor cable 2li, 2l as illustrated in FlG. 7. ln this case, the connector pin 3@ is a bare wire and the movable electrode llt) is then provided with a conforming arcuate grooved portion drlA at its end for snugly engaging the wire .':lllA when and as it is being heated and being pressed through the insulation El and into metallic engagement with the underlying conductor Ztl. Simultaneously, the lower heated electrode (il also softens the adjacent insulation and crowds itself into metallic contact with the underside of the conductor Ztl. The flow of welding current is then initiated as described above.

Referring to FIG. 8, it illustrates another method of achieving electrical Contact and mechanical connection of a connector pin or soldering pin l@ to each of the ends of a multiconductor cable 120, llZl. In this case, the connector pin lSli is a bare wire which is initially placed in physical contact with a cable conductor l2@ by physically inserting an end of the pin in a sandwiched condition between such conductor and that portion of the insulating material overlying the same. To facilitate such insertion, one end of the pin may be pointed for easy insertion and/or a narrow small cutting tool such as, for example, an end portion of a razor blade may be used to separate the plastic insulating material from the conductor. In any case, the insertion of the pin results in the overlying insulating plastic material being crowded away from the conductor and forming a conforming pocket for the pin which is then self-maintained in such pocket by the stressed or stretched insulating material. While the end connection thus formed by the protruding pin may be used, preferably a better mechanical and electrical connection between the pin and cable conductor is provided using techniques described above and the electrodes 40 and 4l in FIG. 7 which then function to penetrate the insulating material from each side as a result of heat and pressure supplied to each electrode; and when the corresponding electrode 49, dl is in contact with the pin i339 and conductor 12d, the pin and conductor are welded together.

The pins l2@ prior to insertion may be tnned with solder and may in some cases, after being positioned as shown in FIG. 8, be soldered to the protruding end portion of the cable conductor.

The plastic insulating material may he, for example, Tellen in the various embodiments.

The connecting end pins in FIGS. 7 and 8 may be of various gauge, for example, of 2l), 22 or 24 gauge and be silver or gold plated nickel pins. The fusing of the various elements may be accomplished by welding or brazing or by soldering in one form of the invention described in FIG. 8 in some cases.

Usually, in making the end connections o-f FIGS. 7 and 8, the end connector is fused to the cable conductor at two spaced locations with two successive fusing operations using a single pair of electrodes or in a single operation using two pairs of electrodes.

While the particular embodiments of the present invention have been shown and described, it will be obvi- -ous to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modiiications as fall within the true spirit and scope of this invention.

l claim:

l. Apparatus for making electrical connections .to ilexible ribbon-tape cables wherein conductors irl the form or ribbons are embedded in a plastic material, a pair of pointed electrodes capable of applying pressure in a limited are-a to opposite sides of said tape cable, heating means mounted on each of said electrodes for soften-ing the insulation of said tape cable when and as pressure is being applied to and between said electrodes.

2. ln a method of making electrical connections beltween conductors of two iiexible ribbon-type cables each of which comprise ribbon-type conductors embedded in a plastic insulating material, the steps comprising sandwiching said cables between a pair of heated electrodes, applying pressure between said electrodes to soften and crowd the plastic insulation out of that region between electrodes and adjacent conductors and between adjacent conductors, and applying a welding current through said elements after such heating and application of pressure results in a metal-.to-metal contact between adjacent conductors and between adjacent electrodes.

3. ln the method for making electrical connections between conductors of dilferent ribbon-type cables wherein such conductors rare embedded in a plastic insulating material, the steps comprising superimposing one of such cables on a second cable with the desired conductors to be connected in superimposed relationship, applying heat and pressure simultaneously between the insulating material which overlies such desired conductors to soften and crowd the insulating material away from such desired conductors, and thereafter passing a welding current through the superimposed conductors.

4. Apparatus for making electrical connections to an insulating body having conducto-rs in the form of ribbons in said body, a pair of pointed electrodes capable of [applying pressure in a limited area to opposite sides of said body, heating means on each of said electrodes for softening the insulation on said body when and as pressure is being applied to and between said electrodes.

5. In vthe method of making electrical connections between conductors of two insulating bodies each of which comprise ribbon-type conductors on a plastic insulating material, .the steps comprising sandwiching said bodies between a pair of heated electrodes, applying pressure between said electrodes to soften and crowd the plastic insulation out of that region between electrodes and adjacent conductors and between adjacent conductors, and applying a welding current through said elements after said heating and application of pressure results in a metal-to-metal contact between adjacent conductors and adjacent electrodes.

6. ln the method for making electrical connections between conductors of different insulated bodies wherein said conductors are on plastic insulating material, the steps comprising superirnposing `one of `such bodies on a second body with the desired conductors to be connected in superimposed relationship, applying heat and pressure simultaneously between the insulating material which overlies said conductors to soften and crowd rthe insulating material away from such conductors, and thereafter passing a welding current through the superimposed conductors.

7. Apparatus for making electrical connections to an insulating body having conductors in rthe form of ribbons in said body, a pair of electrodes capable of applying pressure in a limited tarea to opposite sides of said body, heating means mounted on each of said electrodes for softening the insulation on said body when and as pressure is applied to and between said electrodes.

8. Apparatus as set fonth in claim 7 in which one of said electrodes has an arcuate grooved portion at its end for snugly engaging a wire which is to be connected to one of said conductors.

9. In a method for making electrical end connections to flexible ribbon-tape cables wherein conductors are embedded in a plastic material, the steps comprising inserting each of said end connections into one end of said cable in sandwiched relation between a corresponding one of said conductors and the plastic material overlying the same to crowd said overlying material away from the conductor and stress the same with the said material maintaining said end connections against its corresponding conductor, applying heat and pressure to the plastic material on correspondingly opposite sides of said conductor and said end connection by a pair of heated electrodes to soften and crowd the plastic material out of that region between said electrodes and said end connection and said conductor, and thereafter passing a welding current through `said electrodes to weld the end connection to -a corresponding conductor.

References Cited bythe Examiner UNITED STATES PATENTS 584,120 6/ 97 Payne et al. 219-91 1,613,957 1/27 Madden 219-86 2,343,664 3/44 Heiser et a1. 29-15555 2,349,495 5/44 Gilliam et al. 219-78 2,977,672 4/61 Telfer 219-58 2,982,938 5/61 K'lumpp 339-97 RICHARD M. WOGD, Primary Examiner. ANTHONY BARTIS, Examiner.

Claims

1. APPARATUS FOR MAKING ELECTRICAL CONNECTIONS TO FLEXIBLE RIBBON-TAPE CABLES WHEREIN CONDUCTOR IN THE FORM OF RIBBONS ARE EMBEDDED IN A PLASTIC MATERIAL, A PAIR OF POINTED ELECTRODES CAPABLE OF APPLYING PRESSURE IN A LIMITED AREA TO OPPOSITE SIDES OF SAID TAPE CABLE, HEATING MEANS MOUNTED ON EACH OF SAID ELECTRODES FOR SOFTENING