GB1037855A - Quad construction - Google Patents

Abstract

1,037,855. Quad construction. STANDARD TELEPHONES & CABLES Ltd. April 3, 1964 [April 10, 1963], No. 13823/64. Heading H1A. [Also in Division B5] The four conductors 1 of a quad are spaced from each other by longitudinal insulating webs 2. As illustrated in Fig. 6 (not shown), the quad is made by feeding the conductors from spools 10 to an extrusion press 11 in which a single cylindrical sleeve of thermoplastic material is extruded around the conductors and is drawn inwards under vacuum to form portions 3 between the conductors and portions 4 which may (Fig. 2, not shown) or may not completely surround the conductors depending on the vacuum and the flexibility of the plastic. Alternatively the insulated conductors may be spaced on the external surface of a cylindrical insulating sleeve 8 (Fig. 3, not shown). In each embodiment the conductors 1 may first be insulated individually with a material which may or may not be the same as the sleeve but which is welded to the sleeve during the above extrusion process. To prevent unequal stresses in the conductors and corresponding changes in electrical characteristics when the quad is wound on to a drum 15, a twist is imparted to the quad either by rotating the frame 21 carrying the take-up drum 15 (Fig. 6, not shown) or by rotating the extruder die 12 together with the frame carrying the feed spools 10 (Fig. 4, not shown). The quads may be bunched to form cables in which adjacent quads may have different twist lengths or directions of twist. The insulant may be a foamed or solid thermoplastic material such as PVC, polyethylene or polypropylene.