GB1558633A

GB1558633A - Junper cable

Info

Publication number: GB1558633A
Application number: GB2563077A
Authority: GB
Original assignee: Advanced Circuit Technology Inc
Current assignee: Advanced Circuit Technology Inc
Priority date: 1976-06-21
Filing date: 1977-06-20
Publication date: 1980-01-09
Also published as: JPS6311752B2; FR2356247B1; JPS52156395A; DE7719278U1; DE2727641C2; FR2356247A1; DE2727641A1

Description

(54) JUMPER CABLE (71) We, ADVANCED CIRCUIT TECH NOLOGY, INC., a Corporation organised under the laws of the State of New Hampshire, U.S.A., of Columbia Circle, Congress Industrial Park, Merrimack, New Hampshire, U.S.A., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to electrical connecting devices and to methods of manufacturing the same, and more particularly to improvements in multiple conductor jumper cables and to methods for manufacturing the same.

Various flat multiple conductor jumper cables are well known in the art and are available commercially. At the current state of the art a principal obstacle to wide spread adoption of multiple conductor jumper cables is the relatively high manufacturing cost due primarily to direct labor costs. Another factor limiting wide spread adoption of multiple conductor jumper cables is the inability of known art to simply and economicallv produce jumper cables of other than sim,ple geometrical constructional form.

Shiells U.S. Patent 3601755 proposes forming a multiple conductor jumper cable startin with conventional round wire.

According to Shiells areas of the round wires between the wire ends are rolled flat so as to increase flexibility of the wires in the flattened areas, while the unflattened ends of the wires remain sufficiently strong and rigid to permit direct connection without the need of a special connector assembly. For cabling, Shiells then assembles a plurality of flattened wires in generally parallel spaced relationship and bonds the assembled wires to a plastic laminate. An obvious disadvantage of the Shiells method is the requirement of precision aligning the individual wires which may be somewhat difficult and may add appreciably to production costs. Also, contact design and conductor terminal location are severely limited by the Shiells method.

Another prior art method for forming multiple conductor jumper cables is taught by Key U.S. Patent 3731254. Key discloses a jumper cable comprising a flat multiconductor cable terminated at opposite ends by L-shaped stamped metal terminal posts assembled in a dielectric housing.

Fabrication of the jumper cable disclosed by Key and attachment of the individual terminal posts requires a number of separate precision steps which may add appreciably to manufacturing costs. Another disadvantage of the jumper cable disclosed by Key is the possibility of failure of the connections between the conductor cable and the terminal posts.

It is thus a principal object of the present invention to provide a novel multiple conductor jumper cable having a flexible central portion and rigid terminal ends.

Another object of the present invention is to provide a relatively simple and inexpensive method for producing a cable of the type above described. Yet another object of the invention is to provide a novel multiple conductor jumper cable in which the terminal ends are formed integrally with the conductor central portions, and in which the conductor and contact design and location can be of relatively complicated geometrical constructional form.

According to the invention there is provided a method of manufacturing a jumper cable having a plurality of spaced metallic conductors, including the steps of providing a metallic substrate which comprises a metallic sheet, mechanically and/or chemically removing portions of said substrate so as to define said conductors, and at least partly sandwiching said conductors between sheets of flexible electrically insulating material, whereby each said conductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.

In one arrangement there is provided a method of manufacturing a jumper cable having a plurality of spaced metallic conductors, including the steps of providing a relatively rigid metallic sheet, mechanically and/or chemically removing portions of said sheet so as to define said conductors, and at least partly sandwiching said conductors between sheets of flexible electrically insulating material, whereby each said conductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.

In another arrangement there is provided a method of manufacturing a jumper cable having a plurality of spaced metallic conductors, including the steps of providing a metallic substrate which comprises a metallic sheet having mesas formed on edge regions of said sheet, mechanically and/or chemically removing portions of said substrate so as to define said conductors, and at least partly sandwiching said conductors between sheets of electrically insulating material, whereby each said conductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.

Generally, in accordance with the present invention a jumper cable comprising a plurality of spaced metallic conductors including one or more flexible areas and integral rigid terminals is formed as follows: Method (A): Starting with a relatively rigid metallic sheet, selectively reduce the sheet in cross-section so as to define the conductor patterns and terminal ends, and to render flexible, (at areas of reduced cross-section), areas of the conductors. Reduction may be by chemical milling (i.e. chemical etching) or mechanical milling. Method (B): Starting with a metallic sheet having a thickness approximating that required for the conductor flexible areas, one or more mesas of thickness approximating that required for the terminal ends are formed on the edge regions of the sheet. The mesas may be formed by plating or casting so that the thickened edge regions are integral with the sheet central areas. The resulting contoured substrate is then chemically milled (i.e. chemically etched) or mechanically milled so as to define the conductor patterns and terminal ends. In either method, the metallic conductors are laminated between flexible insulating films which support and maintain the metallic conductors in spaced relation to one another.

The invention also includes a jumper cable manufactured according to the method of the invention.

For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein like numbers depict like parts, and : - Fig. 1 is a perspective view of one form of multiple conductor jumper cable constructed in accordance with the present invention; Fig. 2 is a block diagram illustrating a process for producing the jumper cable of Fig. 1 in accordance with the teachings of the present invention; Figs. 3-10 are perspective views of jumper cable at various stages of formation in accordance with the process of Fig. 2; Fig. Ii is a perspective view of basic elements of a forming press useful in prac- ticing the process of Fig. 2; Fig. 12 is a block diagram illustrating an alternative process for producing the jumper cable of Fig. 1 in accordance with the teachings of the present invention; Figs. 13-17 are side elevational views partly in section, illustrating some of the basic elements of apparatus for performing the process of Fig. 12; Figs. 18-20 are perspective views of jumper cable at various stages of formation in accordance with the process of Fig.

12; Fig. 21 is a side elevational view of a jumper cable made in accordance with the present invention, and showing exemplary modes of connection, Fig. 22 is a block diagram illustrating still another alternative process for producing the jumper cable of Fig. 1 in accordance with the teachings of the present invention; Figs. 23-28 are perspective views of jumper cable at various stages of formation in accordance with the process of Fig. 22; Fig. 29 is a perspective view of basic elements of a forming press useful in practicing the process of Fig. 22; Fig. 30 is a block diagram illustrating yet another process for producing the jumper cable of Fig. 1 in accordance with the teachings of the present invention; Fig. 31 is a perspective view of jumper cable at an early stage of formation in accordance with the process of Fig. 30; Fig. 32 is a side elevational view partly in section, illustrating basic elements of apparatus for performing the process of Fig. 30; and Fig. 33 is a perspective view of jumper cable at an intermediate stage of formation in accordance with the process of Fig. 30.

As used herein the terms "rigid" and "flexible" are employed in their relative sense and with regard to an intended utility. For example, when the term "flexible" is used for describing selected areas of jumper cable in accordance with the invention, it is intended that the jumper cable have, at such areas, the capacity to be bent, or twisted within predetermined limits without fracture or fatigue. The particular circuit design will determine the required degree of flexibility. The term "rigid" as applied to the cable terminals is intended that the terminals are sufficiently stiff and rigid to permit direct assembly and connection of the terminals (e.g. as by soldering) to a circuit board.

One embodiment of jumper cable in accordance with the present invention is shown in Fig. 1 of the drawings. Referring to Fig. I, for illustrative purposes the jumper cable 20 is shown comprising six spaced metallic conductors 22. It will be understood however, that the jumper cable may comprise any number of conductors as may be desired. Each conductor 22 comprises a flexible central portion 24 extending between rigid terminal ends 26 and 28.

Conductors 22 have dimensions, and shapes corresponding to the required design criteria, e.g. current carrying capacity, flexibility requirements, and cable geometry. Typically, those portions of conductors 22 which are intended to be flexible will have a thickness in the range of 0.03 mm. to 0.1 mm., depending on the degree of flexibility required and the hardness of the metal. Terminal ends 26 and 28 typically will have a thickness in the range of 0.2 mm. to 1.0 mm. or more, depending on the degree of stiffness required and the hardness of the metal.

As seen in Figs. 1 and 21, terminal ends 26 and 28 are integral extensions of the conductor central portions 24. Terminal ends 26 and 28 may be formed or shaped for the particular connection purpose required. Thus for example, terminal ends 26 may be bent at right angles at 30 for insertion into apertures 34 in a circuit board 32, while terminal ends 28 may be bent and formed as at 36 for connection to solder cups 38 of connector 40 (Fig. 21).

Preferably the terminals are offset from one another as shown so as to provide greater isolation between adjacent connection points. Obviously terminal ends 26 and 28 will be sized and spaced to meet design criteria for the desired geometrical constructional form or for mating with standard terminal connectors. The manner by which the terminal ends are formed will be described in detail hereinafter.

The individual conductors 22 are supported and maintained in spaced relation to one another by -sandwiching the conductors 22, between first and second dielectric films 42 and 44, respectively. As seen in Fig. 2, film 42 is bonded to the bottom surface of conductors 22, and preferably also extends partially under the terminal ends, e.g. as at 46 and 48. Film sheet 44 is bonded across the top surface of conductors 22, and preferably extends to and may cover the terminal ends (46, 48).

Films 42 and 44 are also bonded to each other in the areas between conductors 22.

Films 42 and 44 preferably are formed of an electrically insulating polymeric film material such as a polyester, polypropylene, polyimide, cellulose triacetate, polyethylene terephthalate or other readily available flexible film. The film thickness is not critical to the invention and will depend upon the particular film or films employed, required degree of flexibility and electrical insulation requirements. Films 42 and 44 may be bonded to conductors 22 by adhesive means such as a thermoplastic or thermosetting adhesive, or one or both of films 42 and 44 may be formed in-situ on the conductors as by casting in known manner.

One embodiment of the present invention is based in part on mass forming a plurality of metallic conductors from a metallic substrate or sheet by selectively reducing the sheet in cross-section so as to define the conductor patterns, areas of relative flexibility and integral rigid terminal ends.

Another embodiment of the present invention entails mass forming a plurality of metallic conductors from a contoured, metallic substrate by selectively reducing the substrate in cross-section so as to define the conductor patterns and integral rigid terminal ends. In another embodiment the metallic substrate may be reduced by chemical milling, i.e. chemical etching, or by mechanical milling, e.g. grinding or skiving, precision die cutting, or a combination of one or more such techniques.

Figs. 2-10 illustrates the formation of a flexible jumper cable in accordance with one embodiment of the present invention employing chemical milling (i.e. chemical etching) techniques.

A metallic sheet 50 preferably of a thickness substantially equal to that required for the terminal ends of the completed cable is provided. In the illustrated case the metallic sheet comprises 0.25 mm. thick copper. Thereafter as shown in Fig. 3 a plurality of registration holes (52 and 54) are formed at spaced positions in the sheet.

The purpose of registration holes 52 and 54 will become clear from the description following. The next step involves coating the metallic sheet top and bottom surfaces 56 and 58, at a coating station 60 (Fig. 2) with conventional acid resist (resistant) materials 62 and 64, respectively. Then one side of the sheet (e.g. top side 56 and layer 62) is exposed, at an imaging station 66, to a negative artwork image of the desired conductor pattern 68 and also including a border area 70 at the edges of the sheet (see Fig. 4). This artwork is regi stered to the metallic sheet using registration holes 52 and 54. Simultaneously layer 64 is entirely exposed to light at imaging station 66. Those areas of resist coating 62 and 64 exposed to light are altered to a lower molecular weight polymer. The purpose of border area 70 will become clear from the following description. The sheet is then immersed in a preferential solvent and developed at a treating station 72, with the result that the exposed bottom resist layer 64, and the exposed portions of resist layer 62 (i.e. the conductor pattern 68 and border area 70) remain intact while the unexposed areas 74 are dissolved away leaving a resist layer 62 in positive image of the desired conductor pattern 68 and border area 70.

The next step involves chemically milling (i.e. chemically etching) the exposed metallic areas by contacting sheet 50 with an acid etching solution at an etching station 76. Etching is controlled so as to remove metal to a depth which substantially equals that desired for the flexible central portions 24 of the conductors. For example, if 0.075 mm. thick flexible conductors are desired, etching should be controlled to a depth of 0.075 mm. Spray etching has been found to be especially suitable for obtaining precision control of the etching step.

Thereafter, the sheet is treated in a stripping station 78 wherein the acid resist material remaining on the sheet is removed from both sides of the sheet. The resulting sheet appears substantially as shown in Fig. 5.

The next step is to partially cover the etched side of metallic sheet 50 with a thin, flexible insulating film such as 3 mil polyimide film 80. As shown in Fig. 6, film 80 is cut to a size and shape so as to cover the central conductor areas of sheet 50, but leaving uncovered end portions 82 of the conductors and of the border areas 70.

Film 80 is applied to sheet 50 at covering station 84 (Fig. 2), and the film is bonded to the metallic sheet by means of a suitable adhesive such as a thermoplastic or thermosetting adhesive.

Metallic sheet 50 is then turned over, and the sheet returned to coating station 60 where the sheet surfaces 56 and 58 (and film 80) are covered with layers of conventional acid resist (resistant) material 88, 90 (Fig. 7). Then, using registration holes 52, 54 to ensure front-to-back image registration, resist layer 88 is exposed to a negative artwork pattern redefining the conductor end portions 82 and border area 70. However, the central areas of the conductor pattern are not masked in this imaging step. The sheet is then treated in treating station 72, with the result that exposed portions of the resist layers 88, 90 remain intact while the unexposed areas are dissolved away as before. The resulting structure appears substantially as shown in Fig. 8.

Sheet 50 is then chemically milled (i.e.

chemically etched) in etching station 76 as before, until breakthrough occurs. This should occur at a depth of 0.175 mm. using the exemplary panel thickness and first etch depth given above. At this point the conductor patterns and the relative thicknesses of the conductor flexible central portions and rigid terminal ends are determined. Both sides are next stripped of all resist at station 78. The resulting sheet appears substantially as shown in Fig. 9.

As depicted in Fig. 10, a thin insulating film such as 3 mil polyimide film 92 is then cut to size and shape and placed in the cavity defined by end portions 82, at covering station 84. Film 92 is then adhesively bonded in known manner to the conductor central portions, and to film 80.

As seen in Fig. 10, the resulting structure is a copper panel comprising a plurality of spaced conductors including relatively thin central portions 24 and relatively thick end portions 82 joined at a relatively thick common border 70, and with the central portions 24 laminated between a pair of thin films 80, 82.

At this point the exposed copper preferablv is plated at a plating station 96 with a tin/lead alloy or a precious metal, using border 70 as a common bus bar. Thereafter, using border 70 for support and registration, the resulting structure is passed to a forming station 98 where end portions 82 are cut free from border 70, and the end portions 82 shaped for the desired connection purpose by means of a forming press 100 (Fig. 11). The resulting structure is a multiple conductor jumper cable. It is to be understood that while only two conductors are depicted in the foregoing processing figures, sheet 50 may have a width suited to provide several jumper cables of a given number of con, ductors. Thus, for example, a hundred conductor wide structure can be produced for cutting, for example, into twenty jumper cables of five conductors each.

An alternative method and apparatus for producing multiple conductor jumper cable in accordance with the present invention is shown in Figs. 12-20. The embodiment of Figs. 12-20 is based upon the use of mechanical milling techniques for selectively reducing a metallic sheet to define the conductor patterns and thickness.

Referring to Figs. 12-17, the illustrated process basically comprises a three-step roll-to-roll manufacturing process. The first step involves selectively thinning a roll of metal by grinding the surface of the metal in a grinding station 101. Referring in particular to Figs. 13-14, grinding station 101 comprises a frame in the form of a horizontal base 102, generally vertical paired side members 104 and 106 (only one of each pair is shown) and a grinder frame member 108 disposed on base 102 between members 104 and 106. Disposed within the frame are a supply reel 110, precision grinding means indicated generally at 112, and first recovery reel 114.

As seen in Fig. 13, supply reel 110 is disposed on vertical side members 104 for rotation on a horizontal shaft 111. The latter is supported by members 104 and known bearing means. An elongated strip 115 of metal, e.g. copper, is carried on reel 110. Strip 115 is threaded through grinding means 112 to first recovery reel 114.

The latter is supported on a horizontal shaft 116 side members 106 and known bearing means. Supply reel 110 is mechanically coupled to a brake means (not shown) while first recovery reel 114 is mechanically coupled via a suitable drive and transmission (not shown) to an electrical motor 118.

Grinder frame 108 comprises a main support base 120 fixedly attached to base 102 and a moveable support 122 disposed adjacent main support 120. Moveable support 122 is adapted for vertical movement between (1) a first raised position in which a grinding wheel 124 carried by support 122 is disposed vertically above copper sheet 115, and (2) a second lowered position in which the grinding wheel 124 is in contact with copper sheet 115. The lower limit of movement of support 122 is controlled by adjustable limit means 126 and 128 mounted on supports 120 and 122 respectively. Moveable support 122 in turn is mounted on hydraulic actuatable support piston 123. Grinding wheel 124 is mounted for rotation on a horizontal shaft 130. The latter is supported by support 122, and is mechanically coupled through a suitable drive and transmission (not shown) to motor 118.

Completing grinding station 101 is a vacuum scavenger 134 for collecting metallic fines produced in the grinding operation. Vacuum scavenger 134 is hydraulically connected via a vacuum hose 136 to a reduced-pressure source (not shown).

Operation of the grinding station is as follows: A roll of copper 110 is placed in the feed position in the grinding apparatus.

The copper provided has a thickness substantially equal to the thickness desired for the terminal ends of the jumper cables to be produced. The copper strip 115 is threaded through the apparatus under grinding wheel 124 to recovery reel 114.

Grinding means 112 is adjusted for vertical movement between an upper position in which grinding wheel 124 is disposed vertically above the copper strip 115 under the wheel, and a lowered position in which the grinding wheel will cut into the copper strip 115 to a depth so as to leave a thickness of copper (following grinding) substantially equal to the thickness desired for the flexible areas of the conductors being produced. For example, for producing jumper cables having rigid terminals of about 0.25 mm. thickness and flexible areas of about 0.075 mm. thickness, copper strip 115 should have a thickness prior to grinding of about 0.25 mm. and the round areas should be reduced by grinding to about 0.075 mm.

Once adjusted, the grinding apparatus is activated, and a metered length of copper strip 115 is pulled through the apparatus by recovery reel 114. Metering may be by any linear measuring means known in the art. Preferably, however, one or both side edges of copper strip 115 will be provided with spaced slots 125 (Fig. 18) for engaging with metering sprockets (not shown) on the grinding apparatus. Grinding wheel 124 is then lowered so as to cut into strip 115. Once wheel 124 reaches its lower limit of travel recovery reel 114 is again activated so as to pull a predetermined length of copper under grinding wheel 124.

This results in removal of a predetermined thickness of copper along a predetermined length of strip 115. Grinding wheel 124 then is raised to its upper limit of travel, and the copper strip 115 is advanced a predetermined length by rolling onto recovery reel 114, and the grinding cycle repeated.

The copper is rewound on recovery reel 114 roll in preparation for the next pro cessing step. The copper strip after this first processing step appears substantially as shown in Fig. 18 of the drawings.

The next processing step is designed to produce the circuit pattern by defining the individual conductor width and spacing between the various conductors.

Thus, the copper strip from the first processing step is then slit lengthwise so as to form the individual conductors, and the conductors are then sandwiched between flexible films to form a laminate. These operations are accomplished in apparatus which in a preferred form as shown in Figs. 15-17 comprises a frame having a horizontal base 140, and generally vertical paired from side members 142, 144, 146, 148 and 150 (only one of each pair as shown). Disposed within the frame are a slitting station 152 and a laminating station indicated generally at 154.

Referring in particular to Fig. 15, a supply reel 156 is disposed adjacent the top ends of frame members 142 for rotation on a horizontal shaft 158 (Supply reel 156 constitutes recovery reel 114 from the previous processing step). A take-up reel 160, is mounted adjacent the top ends of frame members 150. Reel 160 is mounted for rotation on a horizontal shaft 162.

The sheet slitting means comprise a pair of opposed cutting wheels 164 and 166, respectively, including a plurality of engaged male and female cutting dies 168 and 170, respectively (see Fig. 16). Cutting dies 168 and 170 are adapted so as to allow portions 172 of the copper strip (i.e. the intended circuit conductors) to pass untouched, while shearing out material between the conductors as waste 174 (see Fig.

19). The latter is collected in a waste collector 176. One or both cutting wheels 164 and 166 are mechanically connected through a drive 178 to a motor 180. Cutting dies 168 and 170 are adapted for adjustment so as to provide a predetermined number of conductors 172 of predetermined width and spacing.

The laminating station 154 includes upper and lower film dispensing means 182 and 184, respectively. The latter are in the form of reels each containing a supply of flexible dielectric film 186 and 188, (e.g.

3 mil polyimide film). Referring in particular to Fig. 19, upper film 186 and lower film 188 each comprise an elongate prewindowed continuous strip, of width slightly greater than the combined width of spaced conductors 172. Both films 188 and 186 include a plurality of pre-punched slots 190A and 190B for mating the prewindowed film with the flexible areas 172 of the copper conductors. Completing the laminating station are a plurality of opposed laminating rollers 192, 196, and 194, 198, respectively. One or more of the aforesaid rollers may be driven by suitable means known in the art.

In operation, the reel of copper from the first processing step (reel 114) is placed in the supply reel position of the slitting and laminating apparatus. The copper strip 115 is threaded through the apparatus to the recovery reel 160. Cutting wheels 164 and 166 (which had been previously adjusted to define desired conductor width and conductor spacing) are then closed so as to pierce the copper strip. The copper strip is then advanced through slitting station 152 and into laminating station 154.

It should be noted that strip 115 and the individual conductors 172 are maintained under tension between reels 156 and 160 throughout the slitting step and also during the laminating step.

The laminating step is an extension of the cutting step. The slit, i.e. free floating conductors are held in tension between reels 156 and 160 and passed between the pre-punched upper laminating film 186 and pre-punched lower laminating film 188.

Upper laminating film 186 and lower laminating film 188 is aligned with the conductors 172 so that the flexible areas 172 of conductors are registered intermediate slots 190 leaving the thick area 191 completely free of film. The conductors and insulating films are passed between heated nip laminating rollers 192, 196 and 194, 198, respectively, where the insulating films (which had been previously coated with a thermal setting adhesive} are bonded to the conductors, and each other.

The resulting structure is a elongate series of spaced copper conductors 172 having bare raised "finger areas" 191 laminated between dielectric films 186 and 188 as shown in Fig. 19.

Final processing involves passing the Fig. 19 structure to an end forming station 204 where the structure is cut mid-way of the finger areas ill (see Fig. 20), and end shaping will be performed simultaneously as before, by means of an forming press, e.g. press 100, (Fig. 11).

If desired the finger areas 191 may be preplated in known manner to improve solderability prior to final cutting and forming.

Fig. 22-29 illus after as shown in Fig. 23 mesas 252 and 254 are formed on the opposite edges of sheet 250 by selectively plating the sheet, in known manner, at a plating station 255.

Mesas 252 and 254 should have a thickness approximating that required for the terminal ends of the completed cable. For example, for producing jumper cables having rigid terminal ends of about 0.25 mm.

thickness, mesas 252 and 254 should have a thickness of about 0.25 mm.

The next step is to cover partially one side (e.g. side 256) of substrate 250 with a thin, flexible insulating film such as 3 mil polyimide film 4. As shown in Fig. 24, film 44 is cut to a size and shape so as to cover the relatively thin central portion 260 of substrate 250, but leaving uncovered the relatively thick mesas portions 262.

Film 44 is applied to substrate 250 at covering station 264 (Fig. 22), and bonded to the substrate 250 by means of a suitable adhesive such as a thermoplastic or thermosetting adhesive.

Substrate 250 is then passed to a coating station 260 where both surfaces 256 and 257 of the substrate, and also film 44 are covered with layers of conventional acid resist (resistant) material 266 and 268 (Fig.

25). The next step involves exposing one of the resist layers to a negative artwork pattern at an exposure station 267 so as to define desired conductor patterns 270 and also a border area 272. The purpose of border area 272 will become clear from the description following. Simultaneously the entire layer 268 is also exposed to light.

The areas of resist coating 266 and 268 exposed to light are altered to a lower molecular weight polymer. The sheet substrate is then immersed in a preferential solvent or developer at a treating station 274, with the result that the exposed areas of layer 266 and layer 268 remain intact while the unexposed areas of layer 266 are dissolved away exposing surface 257 (see Fig. 26).

The next step involves chemically milling (i.e. chemically etching) the exposed metallic areas by contacting the Fig. 26 coated substrate with an acid etching solution at an etching station 276. Etching is continued until breakthrough occurs. At this point the conductor patterns and the relative thicknesses of the conductor flexible central portions and rigid terminal ends are determined. Both sides are next stripped of all resist at a stripping station 278. The resulting structure appears substantially as shown in Fig. 27. (In Fig. 26, the structure is shown turned over for the purposes of clarity).

As depicted in Fig. 28, a thin insulating film such as 3 mil polyimide film 42 is then cut to size and shape and placed on the uncovered surface 257 of substrate 25Q at covering station 279. Film 42 is then adhesively bonded in known manner to the conductor central portions, and to film 44.

As seen in Fig. 28, the resulting structure is a metallic structure comprising a plurality of spaced conductors 270 including relatively thin central portions 224 and relatively thick end portions 226 joined at a relatively thick common border 272, and with the central portions 224 sandwiched between a pair of thin film 42 and 44 to form a laminate.

At this point the exposed areas of metal preferably are plated at a plating station 280 with a tin/lead alloy or a precious metal, using border 272 as a common bus bar. Thereafter, using border 272 for support and registration, the resulting structure is passed to a forming station 281 where end portions 226 are cut free from border 272, and the end portions 226 shaped for the desired connection purpose by means of a forming press 282 (Fig. 29).

The resulting structure is a multiple conductor jumper cable in which each conductor has a central flexible area and integrally formed rigid terminal ends. It is to be understood that while only three coiiductors are depicted in the foregoing processing figures, sheet 250 may have a width suited to provide several jumper cables of a given number of conductors.

Thus, for example, a hundred conductor wide structure can be produced for cutting, for example, into twenty jumper cables of five conductors each.

Yet another alternative method and apparatus for producing multiple conductor jumper cable in accordance with the present invention is shown in Figs. 3033. The embodiment of Figs. 30-33 is based upon the use of mechanical milling techniques for selectively reducing a metallic substrate to define the conductor patterns.

Referring now to Figs. 23 and 30-33, a metallic substrate 250 having mesas 252 and 254 is provided as before. Then a plurality of metallic substrate members 250 are mounted in spaced relation onto an elongate flexible carrier film 338 (Fig. 31) at a mounting station 355, and the resulting structure is rolled onto a reel 156 (Fig.

32).

The next processing step is designed to produce the actual circuit pattern by defining the individual conductor width and spacing between the various conductors.

Thus, the metallic substrates 250 are slit so as to form the individual conductors, and the conductors laminated between flexible films. These operations are accomplished in a combination slitting and laminating apparatus which in a preferred form as shown in Fig. 32 is substantially identical to the slitting and laminating apparatus shown in Figs. 15-17, supra.

Thus, the slitting apparatus includes a slit- ting station 152 which comprises a pair of opposed cutting wheels 164 and 166, respectively, including a plurality of adjustable, engaged male and female cutting dies 168 and 170, respectively, as before (see Fig. 16). Cutting dies 168 and 170 are adapted so as to allow portions 372 of the metallic substrate (i.e. the intended circuit conductors) to pass untouched, while shearing out material between the conductors as waste 374 (see Fig. 33). The latter is collected in a waste collector 176.

The laminating station 154 includes upper and lower film dispenser means 182 and 184, respectively. The latter are in the form of reels each containing a supply of flexible dielectric film 186 and 188 (e.g.

3 mil polyimide film). Referring in particular to Fig. 33, upper film 186 and lower film 188 each comprise an elongate prewindowed continuous strip of width slightly greater than the combined width of spaced conductors 372. As before, both films 186 and 188 include a plurality of pre-punched slots 190A and 190B for mating the prewindowed film with raised areas 391 of the metallic conductors. Completing the laminating station are a plurality of opposed driven laminating rollers 192, 196 and 194, 198, respectively.

In operation, carrier film 338 is threaded through the slitting station 152 between reel 156 and reel 160. Cutting wheels 164 and 166 (which had been previously adjusted to define desired conductor width and conductor spacing) are then closed so as to pierce carrier film 338, and the film is then advanced through slitting station 152 and into laminating station 154. It should be noted that carrier film 338 is maintained under tension between reels 156 and 160 throughout the slitting step and also during the laminating step.

The laminating step is an extension of the cutting step. The slit, i.e. free floating lengths of carrier film 338 are held in tension between reels 156 and 160 and passed between the pre-punched upper laminating film 186 and pre-punched lower laminating film 188. Upper laminating film 186 and lower laminating film 188 are aligned with the conductors so that the flexible areas 372 of the conductors are registered between slots 190A and 190B, leaving the raised areas 391 completely free of film.

The conductors and insulating films are passed between heated nip laminating rollers 192, 196 and 194, 198 respectively, where the insulating films (which had been previously coated with a thermal setting adhesive) are bonded to the conductors and each other. The resulting structure is a plurality of sets of spaced metallic conductors having bare raised "finger areas" 391 laminated between dielectric films 186 and 188 as shown in Fig. 33.

Final processing involves passing the Fig. 33 structure to a forming station 204 wherein sets of conductors may be cut from one another and the terminal ends shaped as before, by means of a forming press, e.g. press 82 (Fig. 29).

If desired the finger areas 391 may be preplated in known manner to improve solderability.

One skilled in the art will recognize a number of advantages the present invention has over the prior art. For example, the invention permits relatively inexpensive mass production of jumper cables of a desired geometrical constructional form, if desired having random conductor location and varying conductor size (and thus current carrying capacity), and varying terminai size and shape. Moreover, the jumper cable rigid terminal ends are formed integrally with the conductor flexible areas.

Thus problems normally associated with attaching terminal ends, and failure in the field, are eliminated.

Certain changes may be made in the above apparatus and process without departing from the scope of invention herein as will be obvious to one skilled in the art.

For example, precision die flattening and cutting techniques are known from the said Shiells U.S. Patent and from IBM Technical Disclosure Bulletin, Vol. 6, No. 1, June 1963, page 8, and may be adopted for defining the conductor spacing and thickness. Moreover, one skilled in the art will appreciate that it is possible to start with a metallic sheet somewhat thinner than desired for the terminal ends. Processing will be as before except preplating will be used not only to improve solderability, but also to deposit sufficient metal to achieve desired terminal thickness. Moreover, mesas 52 and 54 may be formed by casting metal tabs onto the edges of sheet 50. Still other changes will be obvious to one skilled in the art, and it is therefore intended that all matter contained in the above description shall be interpreted in an illustrative and not in a limiting sense.

WHAT WE CLAIM IS: 1. A method of manufacturing a jumper cable having a plurality of spaced metallic conductors including the steps of providing a metallic substrate which comprises a metallic sheet, mechanically and/or chemically removing portions of said substrate so as to define said conductors, and at least partly sandwiching said conductors between sheets of flexible electrically insulating material, whereby each said con

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

as shown in Fig. 32 is substantially identical to the slitting and laminating apparatus shown in Figs. 15-17, supra.

Thus, the slitting apparatus includes a slit- ting station 152 which comprises a pair of opposed cutting wheels 164 and 166, respectively, including a plurality of adjustable, engaged male and female cutting dies 168 and 170, respectively, as before (see Fig. 16). Cutting dies 168 and 170 are adapted so as to allow portions 372 of the metallic substrate (i.e. the intended circuit conductors) to pass untouched, while shearing out material between the conductors as waste 374 (see Fig. 33). The latter is collected in a waste collector 176.

The laminating station 154 includes upper and lower film dispenser means 182 and 184, respectively. The latter are in the form of reels each containing a supply of flexible dielectric film 186 and 188 (e.g.

3 mil polyimide film). Referring in particular to Fig. 33, upper film 186 and lower film 188 each comprise an elongate prewindowed continuous strip of width slightly greater than the combined width of spaced conductors 372. As before, both films 186 and 188 include a plurality of pre-punched slots 190A and 190B for mating the prewindowed film with raised areas 391 of the metallic conductors. Completing the laminating station are a plurality of opposed driven laminating rollers 192, 196 and 194, 198, respectively.

In operation, carrier film 338 is threaded through the slitting station 152 between reel 156 and reel 160. Cutting wheels 164 and 166 (which had been previously adjusted to define desired conductor width and conductor spacing) are then closed so as to pierce carrier film 338, and the film is then advanced through slitting station 152 and into laminating station 154. It should be noted that carrier film 338 is maintained under tension between reels 156 and 160 throughout the slitting step and also during the laminating step.

The laminating step is an extension of the cutting step. The slit, i.e. free floating lengths of carrier film 338 are held in tension between reels 156 and 160 and passed between the pre-punched upper laminating film 186 and pre-punched lower laminating film 188. Upper laminating film 186 and lower laminating film 188 are aligned with the conductors so that the flexible areas 372 of the conductors are registered between slots 190A and 190B, leaving the raised areas 391 completely free of film.

The conductors and insulating films are passed between heated nip laminating rollers 192, 196 and 194, 198 respectively, where the insulating films (which had been previously coated with a thermal setting adhesive) are bonded to the conductors and each other. The resulting structure is a plurality of sets of spaced metallic conductors having bare raised "finger areas" 391 laminated between dielectric films 186 and 188 as shown in Fig. 33.

Final processing involves passing the Fig. 33 structure to a forming station 204 wherein sets of conductors may be cut from one another and the terminal ends shaped as before, by means of a forming press, e.g. press 82 (Fig. 29).

If desired the finger areas 391 may be preplated in known manner to improve solderability.

One skilled in the art will recognize a number of advantages the present invention has over the prior art. For example, the invention permits relatively inexpensive mass production of jumper cables of a desired geometrical constructional form, if desired having random conductor location and varying conductor size (and thus current carrying capacity), and varying terminai size and shape. Moreover, the jumper cable rigid terminal ends are formed integrally with the conductor flexible areas.

Thus problems normally associated with attaching terminal ends, and failure in the field, are eliminated.

Certain changes may be made in the above apparatus and process without departing from the scope of invention herein as will be obvious to one skilled in the art.

For example, precision die flattening and cutting techniques are known from the said Shiells U.S. Patent and from IBM Technical Disclosure Bulletin, Vol. 6, No. 1, June 1963, page 8, and may be adopted for defining the conductor spacing and thickness. Moreover, one skilled in the art will appreciate that it is possible to start with a metallic sheet somewhat thinner than desired for the terminal ends. Processing will be as before except preplating will be used not only to improve solderability, but also to deposit sufficient metal to achieve desired terminal thickness. Moreover, mesas 52 and 54 may be formed by casting metal tabs onto the edges of sheet 50. Still other changes will be obvious to one skilled in the art, and it is therefore intended that all matter contained in the above description shall be interpreted in an illustrative and not in a limiting sense.

WHAT WE CLAIM IS: 1. A method of manufacturing a jumper cable having a plurality of spaced metallic conductors including the steps of providing a metallic substrate which comprises a metallic sheet, mechanically and/or chemically removing portions of said substrate so as to define said conductors, and at least partly sandwiching said conductors between sheets of flexible electrically insulating material, whereby each said con

ductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.
2. A method of manufacturing a jumper cable having a plurality of spaced metallic conductors, including the steps of providing a relatively rigid metallic sheet mechanically and/or chemically removing portions of said sheet so as to define said conductors, and at least partly sandwiching said conductors between sheets of flexible electrically insulating material, whereby each said conductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region. of relative flexibility to thereby afford said relative rigidity of those ends.
3. A method according to Claim 2, wherein said removal comprises: a partisl removal of some portions of said metallic sheet so as to thin those portions so as to provide said regions of relative flexibility, and a total removal of other portions of said metallic sheet.
4. A method according to Claim 3, wherein said removal is effected by chemical etching and comprises the steps of chemically etching said metallic sheet so as to remove metal from selected portions on one face of said metallic sheet to a first partial depth so as to partially define said conductors, thereafter bonding a said sheet of insulating material to said one face, thereafter removing metal from selected portions on the other face of said metallic sheet by chemical etching so as provide both said thin portions and also total removal and thereby define said conductors, and thereafter bonding a further said sheet of insulating material to said other face.
5. A method according to Claim 3, wherein said removal is effected mechanically and comprises the steps of grindingaway portions of said metallic sheet and thereafter cutting-away portions of said metallic sheet, so as to define said conductors, and there after effecting said sandwiching.
6. A method of manufacturing a jumper cable having a plurality of spaced metallic conductors, including the steps of provide ing a metallic substrate which comprises a metallic sheet having mesas formed on edge regions of said sheet, mechanically and/or chemically removing portions of said substrate so as to define said conductors, and at least partly sandwiching said conductors between sheets of electrically insulating material, whereby each said conductor of said cable includes a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in cross-section than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.
7. A method according to Claim 6, wherein said mesas are formed by plating said edge regions of said metallic sheet.
8. A method according to Claim 6, wherein said mesas are formed by casting metal tabs onto said edge regions of said metallic sheet.
9. A method according to any one of Claims 6-8, wherein said removal is effected by chemical etching and comprises the steps of bonding a said sheet of insulating material to one face of said metallic substrate, thereafter removing metal from selected portions on the other face of said metallic substrate by chemical etching to thereby define said conductors, and thereafter bonding a further said sheet of insulating material to said other face.
10. A method according to any one of Claims 6-8, wherein said removal is effected mechanically and comprises the steps of cutting-away portions of said metallic substrate so as to define said conductors, and thereafter effecting said sandwiching.
11. A method according to - Claim 10, wherein a plurality of said metallic substrate are mounted in spaced relation onto an elongate flexible carrier film, whereby said cutting-away and said sandwiching can be effected sequentially for those substrates.
12. A method according to any preceding Claim, wherein said metallic sheet comprises a metal selected from the group consisting of copper and alloys in which copper is a major constituent.
13. A method according to any preceding Claim, which includes the step of plating exposed portions of said conductor ends so as to increase the thickness of those ends and therefore the relative rigidity thereof, and to improve the electrical conductivity of those ends.
14. A method according to any preceding Claim, wherein said conductor ends are formed as generally flat.
15. A method according to Claim 14, which includes the step of shaping said generally flat conductor ends.
16. A method according to any one of Claims 1-14, wherein, during the manufacture of said cable, said spaced conductors are temporarily maintained in spaced relation by a border portion of said metallic substrate, the method including the step of treating said metallic substrate so as to substantially simultaneously remove said border portion and also shape said conductor ends.
17. A method according to Claim 4 or Claim 9, or according to any claim dependent upon Claim 4 or Claim 9, which includes a step of masking predetermined portions of said metallic substrate so as to prevent chemical etching of those portions.
18. A method of manufacturing a jumper cable, substantially as specifically described herein with reference to at least Figure 2, and/or at least Figure 12, and/or at least Figure 22, and/or at least Figure 30 of the accompanying drawings.
19. A jumper cable manufactured according to any one of Claims 1-18 and comprising a plurality of spaced metallic conductors at least partly sandwiched between sheets of flexible electrically insulating material to thereby maintain said conductors supported in spaced relation to one another, each said conductor of said cable including a pair of spaced, relatively rigid ends and at least one region of relative flexibility between said ends and integral therewith, said ends being thicker in crosssection than said at least one region of relative flexibility to thereby afford said relative rigidity of those ends.
20. A jumper cable according to Claim 19, wherein said conductors are separated portions of a metallic sheet.
21. A jumper cable according to Claim 19, wherein said conductors are separated portions of a metallic substrate comprising a metallic sheet having mesas formed on edge regions of said metallic sheet.
22. A jumper cable according to Claim 21,-wherein said mesas comprise plating upon said metallic sheet.
23. A jumper cable according to Claim 21, wherein said mesas comprise metal tabs cast onto said metallic sheet.
24. A jumper cable according to any one of Claims 19-23, wherein said conductors comprise copper or an alloy in which copper is a major constituent.
25. A jumper cable according to any one of Claims 19-24, wherein said conductor ends have an average cross-section thickness in the range of about 0.2 to 1.0 millimetres, and said at least one region of relative flexibility has an average cross-section thickness in the range of about 0.03 to about 0.1 millimetres.
26. A jumper cable according to any one of Claims 19-25, wherein said insulating material comprises a polymeric film material.
27. A jumper cable according to any one of Claims 19-26, wherein one of said sheets of insulating material covers at least in part at least one of said conductor ends.
28. A jumper cable substantially as specifically described herein with reference to at least Figure 1 and/or at least Figure 21 of the accompanying drawings.