JPH05234428A - Multicore ribbon cable and its manufacture - Google Patents

Abstract

PURPOSE: To provide a lightweight multicore flat ribbon cable excellent in signal density or the like by bonding a large number of insulated conductors to one side of a carrier sheet of single nonsintered polytetrafluoroethylene. CONSTITUTION: Compression rollers having spaced grooves 6 are rotated on a shaft 5 in opposite directions. A large number of insulated conductors are supplied into a pair of nips 8 of the compression roller together with a carrier sheet of single nonsintered polytetrafluoroethylene. The conductors and the carrier sheet of the nonsintered polytetrafluoroethylene are compressed and combined to configure a single-sided cable. Subsequently, this cable is heated at a temperature of about 327 to 400 deg.C in a predetermined period of time, and is cooled after sintering the nonsintered polytetrafluoroethylene, thereby obtaining a multicore flat ribbon cable.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrical signal carrying multi-conductor ribbon cable having a backing sheet bonded to an insulator of a primary conductor.

[0002]

BACKGROUND OF THE INVENTION Insulated electrical signal conductors, either singly or in pairs or groups, are
Or laminated to a backing sheet of 2, or sandwiched or wrapped with the conductor inside a sheath of insulating material to hold the conductor at predetermined intervals to control the amount of signal on the cable, Alternatively, gaining other benefits is well known in the art. Traditionally, individually insulated conductors or groups of conductors are bonded to a backing sheet by an adhesive by heating the insulation of the backing sheet and the conductor to a melting temperature, where the thermoplastic material is the backing sheet and the conductor. Used for pods, or to bond pods with heat, solvent or adhesive by heating and / or pressure around insulated conductors between grooved compression rollers. The pods are usually bonded together to form webs between pairs or groups of conductors and at the edges of ribbon cables.

Non-thermoplastics that do not melt at normal temperatures, such as polytetrafluoroethylene (PTF)
E) is often used in the form of sheets of unsintered PTFE, which are formed around a conductor and when heated and rolled under pressure, in a sintering process from about 327 ° C to about 400 ° C. It will bond itself between and around the conductors during the specified time at the temperature of to provide insulation and pods for the conductors and hold them at fixed distance intervals. Such methods are described in the following references: R. W. Gore, U.S. Pat. No. 3,082,292; W.
Arnold et al., U.S. Pat. No. 3,380,26.
9 and U.S. Pat. No. 3,540,956, C.I. M.
Mortenson US Pat. No. 3,649,4
34 and G.I. A. Hansell, U.S. Pat. No. 4,412,092. Lapping of a conductor in a tube formed in an insulating semi-rigid sheet formed by pressure around a parallel row of conductors to completely enclose the conductor is described by Cruser in US Pat. No. 2,144,144. 872. Similarly, a twisted set of insulated conductors is enclosed between two sheets of insulation, which are heated and pressed around them to surround them at specified intervals (US Pat. 4,012,577 and U.S. Pat. No. 4,096,006).

Conductors insulated with vinyl resin are arranged in parallel by applying a solvent to the insulator to bond the insulator of each conductor to another while holding the conductors at controlled intervals between them. It has been joined to form a flat ribbon cable (US Pat. No. 3,005,7).
39 and U.S. Pat. No. 3,208,896). Similarly, a ribbon cable heats a thermoplastic-insulated conductor under pressure and heat, actually extruding a rod of resin between each pair of conductors to keep the conductors at a fixed distance apart. It can be manufactured by holding it in place (US Pat. No. 3,836,415). This method was used to form the bulk mounting of wiring.

The method described above uses a non-sintered PTFE insulator under heat and pressure when used with an insulating material of a non-thermoplastic insulator, such as non-porous PTFE or porous expanded PTFE, to provide a conductor Surrounding the TPF at the same time
It is necessary to sinter E. The melting and solvent methods will not work with PTFE due to the non-thermoplastic nature of PTFE.

[0006]

SUMMARY OF THE INVENTION The multiconductor (multicore) flat ribbon cable of the present invention has PTFE insulated conductors individually bonded to a single PTFE backing carrier sheet or film. Unbonded, forming a single-sided ribbon cable. This cable is manufactured by holding the unsintered PTFE insulated primary conductors parallel to each other between the guide wires on both sides while pressing them on a carrier sheet of unsintered PTFE by a system of grooved compression rollers. ..
Polyimide film, for example Kapto
n ^R ) non-tacky release sheet and a non-sintered sheet of PTFE film for covering the release sheet can optionally be used to surround the insulated primary conductor and form a simultaneously formed compression The heated ribbon cable is placed in a heated salt bath or air oven to sinter the PTFE sheet and insulation and then, if a salt bath is used, either pass through a rinse of cooling water or remove the air oven. Pass and then cool in a cold air chamber. The guide wire is then slit from each side of the cable and, if used, the release sheet, and the top layer of PTFE is stripped from the cable, leaving a product on one side of the ribbon cable. The spacing between the primary conductors of the cable is controlled by controlling the spacing and configuration of the grooves in the rollers and the amount of pressure the roller exerts on the material passing through them.

Alternatively, a quartz lamp or furnace can be used in place of the salt bath, and a stream of cooled air is used in place of the rinse of the cooling water, whereby
Eliminates the need for a release sheet and a top layer of unsintered polytetrafluoroethylene that protects the cable during salt bath sintering and water washing and cooling, and can make this method more economical ..

It is not necessary to use a continuous PTFE carrier film. Unsintered PTF of specified length
Strips of E carrier film can be used to form single-sided cables with well-defined compartments that can be easily separated for termination and use.
Fluorinated ethylene - coated with propylene thermoplastic adhesive, Kapton (Kapton ^R) polyimide insulating primary conductor can also be used in the above method.

In the single-sided cable of the present invention, the individual insulated conductors can be easily peeled from the carrier film and branched at any point of the individual conductors without the use of special tools or methods of slitting. Can be made The conductors lie in parallel, without the intervening webs between them, allowing for greater signal density / closer spacing than was previously possible with prior art methods. To increase the flexibility of the cable, the air gap between the conductors should be 0.0025-0.0127 cm
(0.001-0.005 inch) is advantageous.

No gluing is used to join the conductor insulation to the carrier strip, thus allowing the cable to be used in the same extreme environment as a standard PTFE ribbon cable. Single-sided cables are currently used in woven or laced cables or in bundles of well-defined conductors, and in many applications where high density, ease of access, and harsh conditions occur, for example, severe It can be used in automated test equipment harness applications that function under conditions (eg, temperature fluctuations).

[0011]

DETAILED DESCRIPTION OF THE INVENTION With reference to the drawings, specific embodiments of the invention are now described in order to more clearly define and describe the invention. FIG. 1 shows a cross section of a cable according to the invention, in which a conductor 1 is surrounded by a non-sintered PTFE insulator 2, preferably by wrapping a tape, and a sheet 3 of non-sintered PTFE between grooved compression rollers. The insulated conductor supplied together with P, leaving a gap 4 in between.
It is bonded to the TFE sheet. The bonded sheet of conductors and insulation are heated to sinter together and cool to form the cable of the present invention.

As shown in FIG. 2, other types of PTFE insulated cables can be utilized in the present invention. For example, a twisted insulated pair of conductors with conductor 1 surrounded by insulator 2 can be bonded to sheet 3 to form a single-sided ribbon cable. FIG. 3 shows a typical pair of compression rollers useful in making cables. The rollers are rotated in opposite directions on axis 5 to force the insulated conductor and a sheet of unsintered PTFE together into nip 8 between the rollers. The groove 6 carries a guide wire for maintaining a selected spacing between the conductors during the manufacturing process. A small portion of the edge of the guidewire and sheet of PTFE insulation is removed at the completion of this process, leaving the finished cable.

When a conventional ribbon cable manufacturing method is used to manufacture the cable of the present invention using, for example, the method shown in FIG. 4, a metallic solid or pre-insulated with unsintered PTFE and a guide wire (not shown). The conductor of the strand,
Feed from the supply reel 21 over the guide and spacing rollers 9 into the nip between the compression rollers 13 and 14. Into the same nip, below the conductor and guidewire, supply a sheet of unsintered PTFE from supply reel 20. At the same time, from the supply reel 11 over the conductor and the guide wire, hot-resistant polymers, e.g., Kapton (Kapton ^R) a release sheet of a polyimide supplied by adjacent conductors and the guide wire, and the unsintered PTFE cover sheet Are fed into the nip on the outside (or on top) of the release sheet. A sheet of polymer is pressed between rollers 13 and 14 to seal the formed insulated conductor and release sheet and groove assembly of the cable in a hot air oven 15 maintained above about 377 ° C. Are allowed to pass for a length of time to sinter all the PTFE material and bond the insulation 2 of the conductor 1 to the sheet 3. The formed heat-sintered cable is cooled by cooling air 16 and passed through a slitter (not shown) to remove the guidewire along each lip and seal the PTFE top layer and the polyimide release layer. Is stripped from the cable onto reels 17 and 18, leaving one side product cable, which is wound onto supply reel 19. The use of a release sheet as in the conventional method described above is not the preferred method.

The preferred materials for the cable are full-density or porous or stretched porous unsintered PTFE carrier film or sheet 3, and full-density unsintered PTFE primary conductor insulation. Or a jacket. Such sheets and insulating materials are generally well known in the art and available from several manufacturers.
Extruded from E granules or emulsion powder.

Expanded PTFE is described in US Pat. No. 3,953,
566, US Pat. No. 4,187,390, US Pat. No. 3,962,153, US Pat. No. 4,096,22.
7 and U.S. Pat. No. 4,902,423, in which PTFE is rapidly drawn into a porous material. In addition, the primary conductor is insulated by a two-layer insulator, and the PTFE layer is outside the two-layer insulator, for example, a combination of expanded PTFE and PTFE, a polymer of polyetheretherketone (PEEK) and P.
Using a combination of high temperature resistant plastics compatible in cables of full density unsintered PTFE such as TFE, where the outer PTFE insulating layer is sintered to a full density unsintered PTFE carrier sheet, Cables can be manufactured.

The manufacturing method was modified to predetermine, for termination, for example by termination of an automated machine, utilizing a fixed length carrier sheet instead of a continuous carrier sheet. A cable can be formed that is easily separable in length. Grooved compression rollers 13 and 14 control the amount of pressure applied to the primary conductors to bond the conductors to the PTFE carrier sheet and control the spacing between the primary conductors. The strength of the bond and the width of the bond contact area used between the conductor and the carrier sheet are controlled by the contour of the groove in the lower roll and the width of the nip 8 between the rollers. The flatter the groove in the lower roller (adjacent to the carrier sheet 3), the lower the bond strength. This is because the contact area between the primary conductor and the carrier sheet will be minimal. Also, decreasing the sintering time will affect the bond strength.

The preferred method of making the cable of the present invention is:
This is schematically illustrated in FIG. The insulated primary conductor is fed from the supply reel 21 across the guide roller 9 into the nip of the compression rollers 13 and 14. Unsintered PTF
A single sheet of E carrier film is fed from the supply reel 20 into the nip below the conductor. After compression, the one-sided cable is passed through an air oven heated to about 327 ° C. to about 400 ° C., for example by an infrared or microwave heating lamp, to burn the conductor insulation to a carrier sheet. Conclude. The cable is cooled, for example by cooling air supplied from the supply vent 23 or in an air-cooled chamber, and the reel 1
Roll up to 9.

The advantage of a one sided ribbon cable is that it provides easy access to each conductor for termination and that any one or group of conductors can be branched to branch out the cable. It is easy to decide the route of. This cable is lighter than a standard PTFE ribbon cable, has a high signal density or minimal center-to-center conductor spacing (does not connect the insulating bars between the conductor's insulation), and has no glue in the cable. do not need. The resulting cable on one side has the maximum usable temperature range of any cable success or failure of that type.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a cable of the present invention in which a single insulated conductor is bonded to a carrier sheet.

FIG. 2 is a cross-sectional view of a cable of the present invention having a pair of insulated stranded conductors bonded to a carrier sheet.

FIG. 3 is a side view of a pair of contoured compression rollers for making a cable of the present invention.

FIG. 4 is a side view of a schematic representation of a method of making a cable of the present invention.

FIG. 5 is a side view of a schematic representation of a preferred method of making the cable of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductor 2 ... Non-sintered PTFE insulator 3 ... Non-sintered PTFE, sheet 4 ... Gap 5 ... Shaft 6 ... Groove 7 ... Groove 8 ... Nip 9 ... Guide and spacing roller 11 ... Supply reel 12 ... Supply reel 13 ... compression roller 14 ... compression roller 15 ... hot air furnace 16 ... cooling air 17 ... reel 18 ... reel 19 ... supply reel 20 ... supply reel 21 ... supply reel 23 ... supply vent

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Claims (10)

[Claims] 1. A multi-core flat ribbon cable comprising a number of insulated conductors self-adhesively bonded to one side of a single unsintered polytetrafluoroethylene carrier sheet. 2. The cable of claim 1, wherein the conductor insulation comprises non-sintered polytetrafluoroethylene. 3. The cable of claim 2, wherein the non-sintered polytetrafluoroethylene insulator is non-porous. 4. The cable of claim 2, wherein the non-sintered polytetrafluoroethylene insulator is porous. 5. The cable of claim 1, wherein the polytetrafluoroethylene carrier sheet comprises full density polytetrafluoroethylene. 6. The cable of claim 1, wherein the conductor comprises a solid or strand metal conductor. 7. The cable of claim 5, wherein the conductor insulator comprises an inner layer of a refractory polymer insulator and an outer layer of a non-sintered polytetrafluoroethylene insulator. 8. A process comprising: (a) placing a number of insulated conductors in a single sheet of non-sintered full density into a pair of nips of a compression roller having spaced grooves. Supplied with polytetrafluoroethylene, (b) compressing said conductor and said sheet into a bonded single-sided cable, (c) said unsintered polytetrafluoroethylene of said cable for a specified time. A sintering process by heating to a temperature of about 327 ° C. to about 400 ° C., and (d) cooling the cable. 9. The method of claim 8, wherein the conductor insulator comprises at least an outer layer of unsintered polytetrafluoroethylene. 10. The method of claim 8, wherein the sintering step is performed by heating the radiation and the cooling step is performed by a cooled gas medium.