Patent GB-870126-A (GB)
Title: Method and apparatus for continuously manufacturing reinforced
IPC: B29C53/74
Filed: 1957-10-08
Abstract: 870,126. Reinforced plastic pipes. COHEN, M. Oct. 8, 1957 [Oct. 8, 1956], No. 31488/57. Class 99(2). Apparatus for making reinforced synthetic plastic pipe comprises a longitudinally extending flexible member or members 86 overlying the surface of a longitudinally extending mandrel 16 and directly engaged by means for moving the member or members longitudinally of the mandrel, and a wrapper 142 helically wound on the mandrel and overlying the member or members. When the flexible member moves longitudinally of the mandrel the wrapper moves therewith, that portion of the wrapper overlying the mandrel and flexible member being adapted to engage the inner surface of the pipe during the formation thereof for moving the pipe therewith and being disengageable from the inner surface of the pipe after formation thereof. As shown, the machine for making the pipe 140 by winding, helically, rovings or woven tapes 122, 124, 126, 128 of fibreglass or other material, comprises a mandrel 16 provided with a number of longitudinal, movable, endless, flexible belts, chains or ribbons 86 engaging rollers or sprockets 88 mounted on a tubular member 60 forming part of the mandrel, the belts extending along the outer surface of the member 60 and in passages defined by splines on a fixed member 56 and between the member 60 and a fixed tubular member 87. The rollers 88, Fig; 10, are mounted between the spaced arms 64 of a fixed member 62 and the belts pass between those rollers and driving rollers 93 formed with worm gears 94 engaged by worm wheels 96 fixed on shafts 98 rotatable in the member 62 and carrying planetary gears 102 meshing with a sun gear 104 secured to the member 87. The member 62 is connected to an adaptor 66 carrying a ring gear 67 driven by a motor via a train of gears ; accordingly, rotation of the members 60, 62 causes the gears 102, 104 to impart rotary motion to the shafts 98 whereby the rollers 93 frictionally drive the belts 86. In a modification, the belts 86 are provided with spaced apertures engageable by teeth on the surface of the rollers 88 which have gears engaging gears on the worm wheels. Spools of glass fibre rovings are mounted on holders 18, 20, 22 and 24, the holder 20 being fixed to a rotatable sleeve 26 provided with a gear 30 meshing with a gear 32 driven by the motor, and the holder 18 being mounted on the inner of concentrically disposed, rotatable members 35, 36, the member 35 carrying a gear 42 in meshed relationship with a gear 44 also driven by the motor ; the holder 22 is supported by a stationary member 14 and the holder 24 is carried by the base of the machine. The rovings 122 are brought on to the member 36 and are disposed in the space 38 between the members 35, 36 the helical path of the rovings being defined by a guide ridge 130, and the rovings 126 are caused to overlie the member 14 in a helical path defined by guide ridge 129, resin from a reservoir 132 being supplied to the rovings 126 through a passage 134. The rovings 124 are wound on to the sleeve 26 in a helical path defined by guide ridge 136, and the rovings 128 are wound directly on to the mandrel 16 after being impregnated with resin supplied from a reservoir 135. Adjacent layers of rovings are wound in opposite directions at a preferred angle of 26 degrees 34<SP>1</SP>, and the layers formed by the rovings 122, 124 are impregnated by the layers of rovings 126, 128. Curing of the thermosetting or thermoplastic resin, e.g. epoxy or polyester resin, is carried out by heating means 139 surrounding the mandrel, or, internal heating means 141 is disposed between the members 60 and 87. To prevent an irregular surface forming on the inside of the pipe due to direct contact between the inner layer of the pipe and the belts 86 a flexible wrapper, preferably of steel, is wound helically on to the mandrel to overlie the belts. The wrapper is taken from a spool and is coated with polytetrafluoroethylene or polytrifluorochloroethylene or a silicone grease to prevent adhesion between the wrapper and resin, the grease being supplied from a reservoir 144 through a channel 146 extending between fixed tubular members 50, 52 and to an applicator pad 152 of felt or foam rubber. Alternatively, an endless wrapper is used and this, when moved off the mandrel, is directed through the member 87. A ribbon of thermoplastic material such as polyvinyl chloride or polyethylene may be substituted for the layer of rovings 122 to provide the pipe 140 with a corrosion and waterproof lining, and the inner and outer surfaces of the pipe may be overlayed by randomly orientated natural or synthetic fibres, e.g. acrylic fibres. The machine may be mounted on a vehicle so that pipe can be manufactured and laid directly. The mandrel may be cylindrical, rectangular or polygonal in cross-section.