GB780562A - Device for corrugating tubes - Google Patents

Abstract

780,562. Making corrugated tubes; stamping. ROBERTSHAW-FULTON CONTROLS CO. Dec. 20, 1955 [May 27, 1955], No. 36502/55. Classes 83 (2) and 83 (4). A device for corrugating tubes by means of internal hydraulic pressure comprises a plurality of pairs of co-operating forming plates, a frame in which corresponding plates of said pairs are slidably mounted, means for moving at least one of each of said pairs of plates to clamp a tube between co-operating plates, a ram for collapsing the tube axially, means for supplying pressure fluid to the interior of the tube, cam follower means on the ram for automatically controlling the successive steps of operation of the ram, cam means co-operable with the follower means for imparting axial movement thereto and motor means for actuating said cam means. The press comprises a bed 10 on which is mounted a frame 14 carrying parallel rods 16 and 18 on which are slidably mounted forming plates 20 urged apart by leaf-springs 24. A second frame 26 mounted on the rod 18 carries a rod 28 on which are slidably mounted similar co-operating spring-loaded forming plates 30. A latch 34 is provided for clamping the frame 26 to the frame 14. Mounted on the bed adjacent the frame 14 is a laterally-movable spring-loaded carriage 38 carrying spacers 42 on a rod 40 which accurately set the axial distance between the forming plates. Lateral movement of the carriage to withdraw the spacers is effected by a fluid-pressure actuated piston motor 47 through a bell-crank lever 50 (Fig. 4). The bed also carries a reciprocable ram 56 comprising a block 58 slidably mounted on tracks 60 and a shaft 62 adjustably threaded into the block. The end of the shaft adjacent the forming plates has a sealing head 72 (Fig. 5) comprising a casing 74 having a recess 76 closed by a plate 78 provided with an arbor 82 which enters the tube to be corrugated. The plate also has another arbor 84 which engages the bottom wall of the recess 76, said arbot carrying a spring-loaded piston 86. A bevelled edge 90 on the piston engages a split-ring 92 and operation of the piston expands the ring to clamp the sealing head to a collar 106. The ram is biased away from the forming plates by a spring 112 secured to a transverse shaft 114 carrying a pinion engaging with a rack 118 secured to the block 58. A cam-shaft 130 driven from a motor 144 carries first and second cams 128 and 136 respectively. The first cam 128 engages a roller 120 on the block 58 and the second cam 136 a roller 122 mounted in a bracket 124 adjustably mounted on the block 58. The cams are adjustable relative to each other by means of a serrated joint in the cam-shaft. The configuration of the first cam controls the rate of movement of the ram during certain portions of the stroke to control the rate at which the tube is collapsed and thus the rate of cold working. The second cam controls the ram movement necessary to insert the arbor 82 into the tube. A swell between operating portions of the cams permits charging of the tube with fluid pressure. In operation, a tube A is placed between the forming plates which are latched in position. As the frame 26 moves to its clamped position it engages a switch 158 to energize the motor 144 which rotates the cams 136 and 138. When the cam has advanced the ram to position the arbor in the tube another cam 148 on the cam-shaft opens a valve 152 to supply fluid pressure to the sealing head 72 from an air-actuated pressure differential pump 166 via a manually operable valve 176. The fluid pressure to the sealing head causes the piston 86 to clamp the head to the collar 106 and fluid-pressure also enters the tube and forms bulges between the forming plates. A further cam 150 on the cam-shaft opens a switch 154 immediately after the cam 148 opens the valve 152 and stops the motor 144. When the fluid pressure builds up and bulges the tube A it also closes a switch 180 which energizes the fluid pressure operated motor 47 to withdraw the carriage 38 and the spacers 42 from between the forming plates. The carriage 38, towards the end of its travel, engages a switch 194 which energizes the motor 144 and causes resumption of rotation of the cam-shaft to advance the ram and collapse the tube. After completion of the operation the cam 128 allows the ram to return under bias of the spring 112, said movement opening a switch 198 to stop the motor 144. A damper 206 controls the return movement of the ram and when the ram reaches the end of its stroke the cam 148 actuates the valve 152 and connects the interior of the tube to a drain to release the sealing head and permit full return movement of the ram.