Patent GB-1194387-A (GB)
Title: Improvements in or Relating to the Manufacture of Pipes
Inventor: BOSTROM RAYMOND OLIVER
IPC: B31C3/00
Filed: 1968-01-17
Abstract: 1,194,387. Continuous pipe making machine. HAWKER SIDDELEY DYNAMICS Ltd. 30 Dec., 1968 [17 Jan., 1968], No. 45288/67. Heading F2P. DYNAMICS Ltd. A continuous bonded-fibre pipe-making machine includes arrangements for the uninterrupted supply of fibre reinforcement and other pipe making materials whereby pipes of unlimited length can be produced without carrying out pipe-jointing operations at intervals. In a machine in which a layer of plastics 2 is extruded from a head 1 over a stationary mandrel, and axial and helical rovings 3 and 10, 21 respectively are applied to the tubular layer of plastics which is drawn off the mandrel by rollers 25, 128 after passing through a heater 24 to bond the rovings to form the pipe, in order to achieve a high and continuous rate of manufacture, the, or each, rotatable annular support 5, 14 has a plurality of spindles 31, Fig. 2, and each spindle 31 carries a relatively large set of rovings cakes one of which is spare and can be brought into use, automatically, when one of the cakes in the set runs out. A plurality of stationary spindles 7, each with working and spare cakes, may be provided for the axial rovings 3 so as to cover, completely, the extruded plastics tube 2. Rovings 33, Fig. 2, from the cakes on adjacent pairs of spindles 31, after passing through their respective tensioners 34, are led to a single guide 35 and applied to the pipe 36 as bands consisting e.g. of 22 rovings 33. It is preferable that no two cakes on the same spindle contain the same length of roving, the cakes being arranged progressively larger towards the outer end of their support spindle. An arrangement of spring-loaded latches (43) and a rod (40) for operating them, reciprocated e.g. by the machine mechanism, are heated in an axial groove in each spindle (38), Fig. 3 (not shown), to ensure that the cakes (49) are moved sequentially when one runs out and to separate the cakes on the spindle. Where the cakes extend in a vertical stack they may be moved by gravity, but a mechanical linkage, Figs. 4-6 (not shown), is required when, as in the case of the helical rovings, the cakes have to be moved horizontally. A device, Fig. 7, which enables those spindles which have lost a cake, to automatically take up another one comprises spindles 62 which are located on a rotatable annular support 61 and which each have a telescopic end section 65 automatically projected therefrom when the respective spindle is short of a cake, so that it extends into a curved portion 68 of a supply shoot 66 and picks up a cake. Three other arrangements, Figs. 8, 9 (not shown), are also described which can, alternatively, be employed to carry out this pick-up operation. The tension means consists of spring-loaded members 110, Fig. 10, which are shaped to allow the rovings to pass to their new positions when the sequential movement of the associated set of cakes takes place, the rovings also passing across a guide 108 to fit into the correct recess 114, additional shifting means (124, 126, 127), Fig. 12 (not shown), being provided if necessary. The angle of lay up of the rovings can also be altered by changing the position of the gatherer, Fig. 10. When a spare cake moves inwardly for use the end of its roving is adhered to the roving of the cake adjacent its inner side to carry it past its individual tensioning and guide means and to the gatherer. A system, Fig. 13 (not shown), may be provided for continuous pressure testing of the completed pipe. The rovings are formed of glass fibres, tapes, or ribbons, with some metal rovings e.g. for electromagnetic detection. Alternatively, carbon fibres or high tensile steel wires may be used with bonding materials e.g. aluminium, lead and zinc alloys.