Patent GB-878036-A (GB)
Title: Improvements in or relating to the manufacture of reinforced plastics pipes and tubes
Inventor: DAVEY EDWARD LESLIE
IPC: B29C48/15
Filed: 1957-04-12
Abstract: 878,036. Reinforced plastic pipes. BRITISH INSULATED CALLENDER'S (SUBMARINE CABLES) Ltd. April 11, 1958 [April 12, 1957; Nov. 11, 1957], Nos. 12100/57 and 35028/57. Class 99(2). A long length of reinforced plastic pipe without joints is manufactured by extruding a length of plastic tubing to form the inner part 1 of the pipe, Fig. 1, and storing successive parts of the extruded tubing in loops of variable length whilst the curved ends of the individual loops are laterally supported. The tubing is then withdrawn from storage and is progressively helically wound with reinforcing tape 2 whereupon successive parts of the reinforced tubing are stored and thereafter withdrawn from storage for progressively extruding thereon a tube of plastic material to form the outer part 3 of the reinforced pipe. As shown in Fig. 4, the pipe part 1 is produced in a first extrusion machine 4 and is drawn off by a caterpillar haul off drive 5. It passes through a variable storage device 6 and a number of layers of metal reinforcing tape are then applied to it by tape applying heads 7. The tubing then passes through a second storage device 8 and afterwards through a second extrusion machine 9 where the outer part 3 is extruded over the outer layer of tape. The storage devices 6, 8 comprise at least two sets of pulleys 10, 11, one of which is movable to and from the other to maintain tension in the tubing embracing them, the pulleys each having a peripheral groove with a semi-circular base and parallel side walls to accommodate the tubing. The side walls may be discontinuous and may form radially extending fingers and may also be lined with cushions of elastomeric material to accommodate tubings of different diameters. In a modification, Fig. 9, the pulleys are without side walls and have around the periphery embraced by the tubing, or around their entire circumference, a plurality of open bearings 16 which are permanently or detachably secured to the rim 17 of the pulley. In another modification, Fig. 11, light alloy or plastic bearings fitted with readily openable caps 19 are applied to the tubing at short intervals as the latter approaches the first pulley of the storage device and are removed as the tubing leaves the final pulley of the device, or as it leaves the first pulley in which case fresh bearings are applied as it approaches the second pulley and so on. In a further modification, Fig. 12, light metal or plastic open bearings are detachably secured to or moulded in an endless belt 20 of flat strip material, e.g. of fabric reinforced rubber which passes around a power driven pulley 21 of the storage loop and a small guide pulley 22 so as to bring the bearings into engagement with the tubing. Alternatively, the bearings are attached to or form part of chain links of an endless chain. The reinforcing tape 2 is of flat steel strip or steel rod of circular, square, rectangular or other polygonal crosssection and is wound into a single layer or two or more layers separated by an intervening layer of plastics.