| 摘要 |
1,076,035. Extrusion / blow - moulding. M. A. J. VERLINDEN. Oct. 9, 1964 [Oct. 10, 1963], No. 41330/64. Heading B5A. [Also in Division B8] A plastics barrel (see Division B8) is formed by moulding, e.g. blowing, a spherical portion from an extruded parison 62<SP>1</SP> and bonding the spherical portion to end members 2 already located in the mould. Polyethylene particles are fed from a hopper (13), Fig. 6, by a screw conveyer (11) between grooves (17), Fig. 6A, in a valve head (16) to fill a duct (14), a bore (19<SP>1</SP>) and a space (24) surrounding the rod of a thickness controller in the form of a piston (26). A stroke regulator (32), operated hydraulically, pneumatically or by means of an eccentric plate, controls the piston (26) during extrusion to vary the thickness of the parison. Increased thickness of the parison wall (at 62<SP>2</SP>), Fig. 8, causes the wall of the moulded barrel to be uniform. The die, formed of two movable halves 33, 34 co-operates with an extrusion head (28). The plastics material, heated by a member (C), is extruded under pressure from a piston (22) which also causes the valve head (16) to close against a seating (16<SP>2</SP>), Fig. 6A. Each half 33, 34 of the die has a movable ring 40, 41 respectively, which holds the respective end member 2 in place. A plug 46, formed with a cone 48, and a plug 51 carrying a pipe 49 form bung-holes, the pipe 49 being connected to a source of compressed air. After extrusion of the parison, the die halves are moved together, edges 63 on the rings 40, 41 cutting off the plastics material. The spherical portion of the barrel is then blown into contact with the die and end members 2 by means of the pipe 49. Alternatively, the spherical portion of the barrel may be formed by injection, casting or centrifuging, the end members 2 being subsequently united thereto. In a modification, the barrel may be formed of glass-fibre reinforced polyester by the following steps. Glass-fibre reinforcing elements are pre-formed by spraying the fibres, with resin, into a rotary mould having a suction wall to hold the fibres in place. These elements are then introduced with polyester resin into a hydraulically operated mould to form the main parts of the barrel. After compression, the parts are cured in an oven before being bonded together. The joint may be further reinforced externally by glass-fibre polyester. |
