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US 4,785,616 AGranted
Manufacture of cables
AssigneeTelephone Cables Limited
InventorClifford Heywood
Life of this patent
Estimating the term…
Abstract
In the manufacture of a cable having a plurality of filamentary members such as wires, optical fibres or the like within an extruded thermoplastic sheath the members are twisted into a periodically reversing helical configuration immediately prior to the extrusion of the sheath around them, and the extruded sheath is rapidly cooled on emergence from the extruder head so as to cause the extrudate to set and thereby retain the members in the twisted condition.
Claims11
A method of manufacturing a cable comprising the steps of:
- (a) twisting a plurality of filamentary members in a periodically reversing helical fashion about a central axis;
- (b) extruding a protective sheath around the twisted members immediately following the twisting step;
- and
- (c) cooling the extruded sheath immediately following the extruding step so as to cause the material of the sheath to set and thereby retain the twisted members in a twisted condition.
1 more element
Apparatus for manufacturing a cable, comprising:
- (a) an extruder head;
- (b) a plate having a plurality of axially directed holes spaced around an axis;
- (c) means for oscillating said plate about said axis within said extruder head;
- (d) means for feeding a filamentary member through each of said holes as said plate is oscillated in use of the apparatus such that, on emergence therefrom, said filamentary members are twisted in a periodically reversing helical fashion;
- (e) means for extruding a sheath of thermoplastic material around the twisted members;
- and
- (f) means for cooling said extruded sheath at a position at which it emerges from the extruder head.
4 more elements
Dependencies are inferred from the claim text.