Patent GB-907195-A (GB)
Title: Suction cleaner hose
IPC: B29D23/18
Filed: 1959-05-22
Abstract: 907,195. Making non-metallic flexible tubes. CANFIELD CO. Inc., H. O. May 22, 1959 [May 28, 1958], No. 17588/59. Class 99 (2). In a method of making a flexible suction cleaner hose, Fig. 23, comprising a cylindrical helical plastic-coated wire coil 1 surrounded by a corrugated, extruded tube 4 of elastomeric thermoplastic material, the coil 1 is inserted into the radially expanded tube 4 which is then allowed to contract on to the coil so as to form corrugations between the convolutions and hold adjacent turns of the coil widely apart. The corrugated tube is then heated to remove stresses therein so that the minimum diameter of the tube is no greater than the internal diameter of the coil and the adjacent turns of the coil are spaced apart by the corrugations a distance several times the cross-sectional diameter of the plasticcoated wire when the heated tube is free of axial restraint. The corrugated tube is then tensioned, cooled and finally allowed to contract axially. As shown in Fig. 3, the coil 1 coated with P.V.C. is mounted on an externally cylindrical horizontal aluminium mandrel 5, the bare ends of the coil being secured to sleeves 16 slidable on the mandrel and held against shoulders 12, 13 thereon by the extended coil. The coil is further extended by moving one of the sleeves 16 away from the shoulder 12 and attaching it by a bayonet type joint to a pin 14 at one end of the mandrel. The tube 4 of P.V.C. is guided from a supply roll 39, Fig. 7, by a roller 40 into a suction cylinder 30 provided with a vacuum connection 31, the free end of the tube 4 being cuffed over one end of the cylinder as at 41 and the other end of the cylinder being sealed by a rubber sleeve 35 secured thereto and which is squeezed on to the tube 4 on application of a vacuum whereby the portion of the tube 4 within the cylinder is radially extended. The mandrel 5 with the coil 1 thereon is introduced into the expanded tube 4 and the vacuum released to allow the tube to contract and grip the coil, the ends of the tube being then cut to the required shape and one of the sleeves 16 released and allowed to move against the shoulder 12. The hose is then heated to shrink the tube 4 into a first normalizing apparatus 44, Fig. 12, which includes a table having a polished aluminium surface and provided on each side with a sprocket driven conveyer chain 47 on which the hose is supported, the hose being rotated by a rack 52 engaging a gear 15 mounted on one end of the mandrel 5 and heat being supplied by radiant heaters 63 mounted above the table and by electric current supplied from a generator 54 through the sleeves 16 to the coil wire. After passing through the apparatus 44 the hose is cooled, removed from the mandrel 5 and placed on a second cylindrical aluminium mandrel 84 on which it rests freely. The mandrel and the hose are then heated in a second normalizing apparatus 66, Fig. 18, comprising a pair of sprocket driven conveyer chains 69 mounted on each side of an aluminium covered table 74 and having rigidly mounted thereon supporting blocks 70, 71 in which the mandrel 84 is rotatably supported, the mandrel being rotated by a tongue 77 on a stub shaft driven by a sprocketchain assembly 80 and heat being supplied by radiant heaters mounted above the table 74. After passage through the apparatus 66, the mandrel and hose are cooled in a cooling apparatus 95, Fig. 20, comprising sprocket driven double chains 69a on which are mounted yokes 98 which support the hose in an axially stretched condition. The hose is finally removed from the yokes 98 and allowed to contract axially.