Composite cable and method of making the same

• US 4,034,547 A
• Filed: 07/06/1976
• Issued: 07/12/1977
• Est. Priority Date: 08/11/1975
• Status: Expired due to Term

• Current Assignee: August W. Loos
• Original Assignee: August W. Loos
• Inventors: Loos, August W.
• Primary Examiner(s): Watkins, Donald
• Application Number:
  US05/700,081
• Time in Patent Office: 371 Days
• Field of Search: 57/9, 57/34 R, 57/139, 57/144, 57/145, 57/146, 57/147, 57/148, 57/156, 57/160, 57/161
• US Class Current: 57/211
• CPC Class Codes: D07B 1/005 Composite ropes, i.e. ropes built-up from fibrous or filamentary material and metal wires
• CPC Class Codes: D07B 1/0686 characterised by the core design
• CPC Class Codes: D07B 1/0693 having a strand configuration
• CPC Class Codes: D07B 2201/2056 arranged parallel to the axis
• CPC Class Codes: D07B 2201/2068 having a load bearing function
• CPC Class Codes: D07B 2201/2073 in circumferencial direction
• CPC Class Codes: D07B 2201/2074 in radial direction
• CPC Class Codes: D07B 2205/2046 Polyamides, e.g. nylons
• CPC Class Codes: D07B 2205/205 Aramides
• CPC Class Codes: D07B 2207/209 Tubular strander
• CPC Class Codes: D07B 2801/12 Strand
• CPC Class Codes: D07B 2801/14 Core
• CPC Class Codes: D07B 2801/24 Rope
• CPC Class Codes: D07B 7/025 Preforming the wires or strands prior to closing

Abstract

A cable is disclosed having a wire rope jacket and a synthetic compressible core of yarn filaments with a specific tensile strength greater than the members of the jacket and which serve as a reinforcing component for the jacket to provide a cable construction suited for service conditions requiring a strength greater than a conventional steel cable. A method of making cable is set forth which lends itself to economical and dependable manufacture wherein a yarn core is drawn through a closing die in a substantially zero twist parallel arrangement and drawing a plurality of wires through the die in timed relation to passage of the core to be helically laid about the core to form a twisted wire rope jacket.

Claims

1. A cable comprising a synthetic core and a metal jacket, the jacket being formed of a plurality of continuous wirelike members helically laid in a layer about the core, the core being formed of a bundle of low stretch lightweight continuous fibers having a high tensile strength to density ratio, the core fibers having a specific tensile strength greater than that of the members of the metal jacket and serving as a reinforcing component for the metal jacket, the core fibers constituting a soft compressible bundle to effect maximum concentration of fibers for a given cross-section and filling interstices between the wirelike members of the metal jacket, the jacket including a plurality of individual wires helically laid in a layer about the core with the wires collectively effecting a hoop tension about the core and applying a compressive force to its outer surface radially inward, the outer surface of the bundle being compressively stressed radially inward in an alternating pattern which uniformly varies axially of the bundle form zones of minimum stress between wires to zone of maximum compressive stress intermediate the zones of minimum stress.

2. A cable comprising a synthetic core and a metal jacket, the jacket being formed of a plurality of continuous wirelike members helically laid in a layer about the core, the core being formed of a bundle of low stretch lightweight continuous fibers having high tensile strength to density ratio, the core fibers being in the form of yarn filaments of aromatic polyamide filaments having individual deniers of 1500, the core fibers having a specific tensile strength greater than that of the members of the metal jacket and serving as a reinforcing component for the metal jacket.

3. A cable comprising a synthetic core and a metal jacket, the jacket being formed of a plurality of continuous wirelike members helically laid in a layer about the core, the core being formed of a bundle of low stretch lightweight continuous fibers having a high tensile strength to density ratio, the core fibers having a specific tensile strength greater than that of the members of the metal jacket and serving as a reinforcing component for the metal jacket, the core and jacket being movable relative to one another.

4. A cable comprising a synthetic core and a metal jacket, the jacket being formed of a plurality of continuous wirelike members helically laid in a layer about the core, the core being formed of a bundle of low stretch lightweight continuous fibers having a high tensile strength to density ratio, the core fibers having a specific tensile strength greater than that of the members of the metal jacket and serving as a reinforcing component for the metal jacket, the cabl having a breaking strength exceeding by 20% the breaking strength of a comparable conventional metal cable formed of AISI 302 stainless steel.

5. The cable of claim 4 wherein the cable is about 30% lighter in weight than that of said comparable stainless steel cable.

6. A composite cable comprising a core and a jacket, the core being formed of a compressible bundle of aromatic polyamide filaments laid in substantially parallel zero twist relation to one another, the jacket being a plurality of wires helically laid in a layer about the core with the wires collectively effecting a hoop tension about the core and compressively engaging the outer surface of the core bundle, the outer surface of the core bundle being compressively stressed radially inward in an alternating pattern which uniformly varies axially of the core from zones of minimum stress between wires to zones of maximum compressive stress intermediate the zones of minimum stress, the core serving as a unitary reinforcing component for the jacket with the core filaments having a specific tensile strength greater than that of the wires of the jacket.

7. A method of making a cable comprising the steps of supplying a continuous multifilament yarn to a closing die to serve as a cable core, spinning a plurality of reels of wire about a spin axis extending through the closing die, drawing a wire from each of the reels through the closing die to be helically laid about the core, and pulling the yarn core through the closing die in a substantially zero twist parallel arrangement in timed relation to passage of the wires through the die to form a composite cable having a twisted wire rope jacket surrounding a parallel laid multifilament yarn core.

8. The method of claim 7 wherein the spinning, drawing and pulling steps are simultaneously perfomred with the yarn core being pulled toward the closing die with a revolving motion about the spin axis of the wires.

9. The method of claim 7 wherein the pulling step is effected by pulling the yarn core filaments under tension and in parallel no twist alignment through a second closing die upstream of the wire reels and the first die.

10. The method of claim 7 including the additional step of preforming each of the wires to set a predetermined helical twist therein to minimize internal stress, prior to each wire passing through the closing die.

11. A cable comprising at least one strand having a core and a jacket, the jacket including a plurality of continuous wirelike metal members laid about the core, the core including a bundle of low stretch lightweight continuous synthetic fibers having a high tensile strength to density ratio, the core fibers being in the form of yarn filaments of aromatic polyamide filaments having individual deniers of 1500, the core fibers having a specific tensile strength greater than that of the metal members of the jacket and serving as a reinforcing component therefor.

12. A cable comprising at least one strand having a core and a jacket, the jacket including a plurality of continuous wirelike metal members laid about the core, the core including a bundle of low stretch lightweight continuous synthetic fibers having a high tensile strength to density ratio, the core fibers having a specific tensile strength greater than that of the metal members of the jacket and serving as a reinforcing component therefor, the core and jacket being movable relative to one another.

13. A cable comprising at least one strand having a synthetic core and a metal jacket, the jacket being formed of a plurality of continuous wirelike members helically laid in a layer about the core, the core being formed of a bundle of low stretch lightweight continuous fibers having ahigh tensile strength to density ratio, the core fibers having a specific tensile strength greater than that of the members of the metal jacket and serving as a reinforcing component for the metal jacket, the strand having a breaking strength exceeding by 20% the breaking strength of a comparable conventional metal strand formed of AISI 302 stainless steel.

14. The cable of claim 13 wherein the strand is about 305 lighter in weight than that of said comparable stainless steel strand.

15. A composite cable comprising at least one strand having a core and a jacket, the core being formed of a compressible bundle of aromatic polyamide filaments laid in substantially parallel zero twist relation to one another, the jacket being a plurality of wires helically laid in a layer about the core with the wires collectively effecting a hoop tension about the core and compressively engaging the outer surface of the core bundle, the outer surface of the core bundle being compressively stressed radially inward in an alternating pattern which uniformly varies axially of the core from zones of minimum stress between wires to zones of maximum compressive stress intermediate the zones of minimum stress, the core serving as a unitary reinforcing component for the jacket with the core filaments having a specific tensile strength greater than that of the wires of the jacket.

16. The cable of claim 15 wherein the cable is a multistrand cable comprising at least three of said one strand units.