The present application relates to this type cable and the improved mass production and termination of such a cable.
Certain termination methods require a potting material to seal the conductor wires in the terminal connector after connection of the conductors to the pins and/or sockets of the connector is made. If the woven cover is left open, as in its tubular configuration, seepage of the potting material into the cover is possible as is often the case. The potting material hardens on the cable and becomes brittle. Flexing of the cable results in cracking and breaking of the hardened potting material, and, quite often, breaking of the conductors.
The invention relates to flexible woven high frequency transmission cables of the type which are generally flat and include a plurality of conductors extending in the warp direction of the cable which transmit high frequency signals such as utilized in communication and computer systems. In routing the cables through the chassis of the computer or other installation, it is often necessary to flex and distort the cable in reaching to a specific location. The cable also encounters considerable wear and abrasion in use. This wear and abrasion, as well as the distortion of the cable conductors in routing the cable, often cause changes in the cable characteristics which influence the accuracy of the signal being transmitted and the life of the cable.
Moreover, programming of certain looms to make large numbers of the cables, particularly in short lengths, is quite inefficient and requires constant machine attendance.
Accordingly, an important object of the present invention is to provide a flexible woven high frequency transmission cable having a unitary woven cover which may be made in any lengths in large numbers in an efficient manner.
Another important object of the present invention is to provide a flexible one-piece woven electrical transmission cable and jacket wherein the jacket protects both the physical and electrical characteristics of the cable and has improved termination programming capabilities.
Yet another important object of the present invention is to provide a woven high frequency transmission cable having an outer tubular woven cover which terminates in a closed flat weave to prevent seepage of potting material back into the cable and cover from a potted terminal connector.
Summary of the Invention
The above objectives are accomplished according to the present invention by providing a cable structure having jacketed sections consisting of an outer woven tubular cover and an inner electrical transmission cable wherein a common weft yarn is woven between the cover and cable to join them physically as one-piece. Non-jacketed sections are included in the cable structure wherein the open tubular weave of the cover is reduced to a closed flat weave with the conductors broken out. In the method, a plurality of jacketed and non-jacketed sections are provided in a continuous cable length. A cut-line section in which all the conductors are bound is woven between the ending non-jacketed section of a first jacketed cable and the beginning non-jacketed section of a second jacketed cable. The continuous length cable structure is severed across the cut-line sections to produce individual jacketed cables. The closed flat weave closes the tubular cover to the seepage of potting material from the connector which is affixed at the non-jacketed end sections.
Brief Description of the Drawings
The construction designed to carry out the invention will be hereinafter described, together with other features thereof.
The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein:
FIG. 1 is a perspective view illustrating a continuous length of unitary jacketed woven transmission cable and method according to the present invention with alternating jacketed and non-jacketed sections;
FIG. 2 is a partial perspective view illustrating a unitary woven jacketed cable and method therefor according to the present invention;
FIG. 3 is a sectional view illustrating jacketed cable sections, non-jacketed cable sections, and cut-line sections woven in a continuous length cable structure according to the present invention taken along line 3--3 of FIG. 2;
FIG. 4 is a schematic view illustrating a section taken along line 4--4 of FIG. 3 according to the present invention;
FIG. 4A is a schematic view illustrating a section taken along line 4A--4A of FIG. 3 according to the present invention;
FIG. 5 is a perspective view illustrating a unitary woven jacketed cable having a jacketed section and a non-jacketed section and method therefor according to the present invention;
FIG. 6 is a schematic view illustrating the catch cord weave for a typical cable woven on a needle loom, the particular view being a schematic of a closed flat weave in a non-jacketed cable section according to the invention; and
FIG. 7 is a schematic view illustrating a terminated unitary woven jacketed cable and method therefor according to the present invention.
Description of a Preferred Embodiment
Referring now in more detail to the drawings, FIGS. 1 and 2 illustrate a continuous length of jacketed woven cable structure 10 is illustrated which includes a plurality of jacketed sections A, non-jacketed sections B, and cut-line sections C. The jacketed section A includes an outer woven cover 12 and an inner woven high frequency electrical transmission cable 14. Any construction may be had for the woven transmission cable 14 in which electrical warp conductors are bound by weaving. The present invention is particularly advantageous with a construction illustrated in U.S. Pat. No. 4,143,236 for a controlled impedance high frequency transmission cable. The cable 14 and cover 12 may be woven together in a one-piece configuration as disclosed in the above identified parent application, U.S. Pat. No. 4,460,803, issued on July 17, 1984, incorporated herein by reference. Transmission cable 14 includes a plurality of warp elements extending in a warp direction which include a number of warp conductors 16 and warp yarns 18. The warp conductors include signal conductors 16a and ground conductors 16b as can best be seen in FIGS. 4 and 4A. Signal conductors 16a are arranged in a substantially side-by-side relationship for transmitting high frequency electrical transmission signals.
Longitudinally extending ground wires 16b are carried on each side of the signal wires 16a. A ground wire 16b is carried on one side of signal wire 16a and a ground wire 16b is carried on the opposing side of each signal wire 16a along the length of the cable. The configuration of the ground and signal wires in the weave pattern of the woven cable may be had in any configuration such as that illustrated in U.S. Pat. No. 4,143,236.
The cable warp yarns 18 are woven with a cable weft yarn element 20 (FIG. 6). The cable weft yarn 20 is interwoven with the warp yarns 18 as well as the conductors 16 which extend in the warp direction and thus form warp elements. This provides an integral woven cable fabric. The cable may also be constructed in a conventional twill weave pattern wherein the conductor elements 16 are the only warp elements in the cable and are woven with cable weft element 20.
Woven cover 12 includes a cover weft yarn element which in the illustrated embodiments consists of the same weft element 20 of the woven cable. Cover weft yarn 20 is woven with a plurality of warp yarns in an open tubular weave configuration around inner cable 14 (FIG. 3).
Outer cover 12 and inner cable 14 are woven simultaneously on a loom, preferably a narrow fabric needle loom. This type loom is fast and utilizes a catch cord 26 and a knitting needle 28 to knit the weft 20 at one edge of the fabric of the cable and cover such as at edge 30 of the cable structure in FIG. 6. Having been taught the construction and method for a one-piece woven jacket and transmission cable according to the invention, one skilled in weaving would readily be able to program the weaving and making of such a cable on a loom.
In a preferred embodiment, which can best be seen in FIGS. 3, 4 and 4A weft yarn 20 is woven in cover 12 with cover warp yarns 31 exclusive of cable 14 for a number of picks. The weft yarn is then broken out of the cover and woven through the cable 14 for a number of picks. The common weft yarn is then broken out and returned to the weaving of outer cover 12. The cover 12 and cable 14 are thus interwoven with each other and physically attached as one-piece. A more detailed description of this construction may be had by reference to U.S. Pat. No. 4,460,803 described above.
Owing to weaving of cover 12 in tubular form, weft 20 tends to pull in the sides of cable 14 altering the spacing of adjacent conductors thus affecting the cable characteristics. Preferably, the edge wires are 28 gauge where the remaining interior conductors are 34 gauge. The heavier gauge wire is sufficient to resist pulling in of the cable sides by weft 20.
Referring now to non-jacketed section B, as can best be seen in FIGS. 3-5, tubular woven cover 12 is reduced to a closed flat woven fabric structure 32. In the flat weave structure 32 all of the cover and cable warp yarns 31, 18 are woven with the weft yarn 20 and the warp conductors 16 are left unbound and freely floated on either side of the flat fabric structure.
Viewing the cable structure of FIG. 3 as being woven from left to right it can be seen that conductors 16 break out of the tubular jacket 12 of the jacketed section A at 34, which is the beginning of the non-jacketed section B. The conductors 16 are broken out on both sides of the closed flat weave 32. Approximately three-quarters of the way down the non-jacketed section B the ground conductors 16b are woven back into the closed flat weave structure 32 and are woven together with the warp yarns 18, 31 of the jacket end cable in the flat weave 32. The remaining conductors 16 weave back into the cut-line section C at 36.
In the preferred embodiment, the cut-line section C is woven as an auxiliary jacketed section of minor length. The weave of the cut-line section C is then the same as the jacketed section A except that it is of only a minor length so that the continuous length cable structure 10 can be severed across this cut-line section.
In accordance with the method, the continuous length cable structure is first severed across the cut-line section C. This produces a number of individual jacketed woven cables having a length corresponding generally to the desired length of the cable in the section A. The woven jacketed cable thus produced will have a non-jacketed section B on each end thereof which is followed by a cut portion of the auxiliary jacketed section C. Thus all the conductors will remain bound in the individually cut and produced woven jacketed cables A. For example, as can best be seen in FIG. 1, the cut cable will include a section A, two sections B on each end thereof and two severed sections C adjacent each section B.
It will be noted, as can best be seen in FIGS. 3 and 7, that the weaving point 34 at the junction of the jacketed section A and the non-jacketed section B on each end thereof will define a closure point where the open interior of the tubular cover 12 is closed. When a terminal connector is fixed to the ends of the jacketed cable A for finishing the cable, as can best be seen in FIG. 7, the interior of the woven cover 12 of the jacketed section A will be closed to the potting material 42. This prevents the tendency of the potting material 42 to flow back into the tubular cover and result in brittleness in the area of the terminal connector and avoids the problems heretofore discussed in connection therewith. The terminal connector 38 is affixed to the end of the jacketed section A and the conductors 16 are terminated in a conventional manner by soldering to sockets 40. In the method, the continuous length cable structure is severed at the cut-line section C. This leaves all the conductors bound at the ends of jacketed sections A. Next, the non-jacketed sections B are severed in the area of line 4A--4A of FIG. 3. This leaves the ground conductors 16b still bound in the flat weave 32, but the signal conductors 16a are cut and free. The signal conductors 16a are thus folded back and positioned for termination. Next, the flat weave 32 may be cut in the area of line 4--4 of FIG. 3. This frees the ground conductors 16b so that they are unbound and available for termination. In this manner, the conductors may be terminated in a programmed and orderly fashion.
In accordance with the method of mass producing unitary jacketed woven transmission cables of the type described herein, a continuous length of cable structure 10 is woven. The continuous length cable structure is best described by viewing it from left to right, as can best be seen in FIG. 1, with an auxiliary jacketed section or cut-line section C as the beginning of the structure or weaving method. Next, a non-jacketed section B is woven on one end of a jacketed section A' and a second non-jacketed B is woven at the other end of the jacketed section A'. The weaving follows with a cut-line section C which is followed by a jacketed section B at the beginning of a second jacketed cable A". At the end of jacketed cable A" is a non-jacketed cable section B followed by a cut-line section C. This weaving pattern is followed along the continuos length of the cable structure 10 until a desired number of individual woven jacketed cables A are produced and severed by cutting the cable structure across the cut-line section C. It will be noted that the non-jacketed section B at the end of woven jacketed cable A' and the non-jacketed section B at the beginning of woven jacketed cable A" define a pair of adjacent non-jacketed sections. There is a cut-line section C between each non-jacketed section in the adjacent pair.
In the method, the jacketed section A is woven to produce a woven jacketed electrical transmission cable as heretofore described. Simultaneously with the weaving of the cable, a woven cover 12 is woven around the woven cable. The woven cover 12 and woven cable 14 are interwoven at selective points of weaving along the length of the cable section 18 so that they are attached together as one piece. In the non-jacketed longitudinal sections B the woven cover 12 is reduced to the flat weave 32 and the warp conductors 16 are broken out of the woven cable and cover at 34 and 36 and extend unbound on either side of the flat weave 32.
While the invention is illustrated as using a single weft system, separate weft systems may be used for the cover and cable with interweaving between the cover and cable being made to effect physical attachment. In this case, a cross-shot shuttle loom may be employed.
The unitary woven electrical transmission cable and jacket have been described and illustrated as woven on a needle loom. In this case, one of the edges of the unitary construction includes the catch cord which catches and is knitted with the weft element along the length of the woven construction on the one side and each pick will include the weft yarn doubled on itself as is conventional with needle loom construction. Other looms and woven constructions may be had while utilizing the invention herein.
While any desired termination of the conductors may be had, FIG. 4 illustrates one such embodiment wherein all of the ground conductors 16b are broken out on top of the closed cover structure for termination to a common bus bar. The signal conductors are floated out on both sides of the flat woven structure for a selected termination.
It will be understood, of course, that while the form of the invention herein shown and described constitutes a preferred embodiment of the invention, it is not intended to illustrate all possible form of the invention. It will also be understood that the words used are words of description rather than of limitation and that various changes may be made without departing from the spirit and scope of the invention herein disclosed.