Patent GB-843970-A (GB)
Title: Flexible tube manufacture and apparatus
IPC: B21D15/10
Filed: 1957-12-12
Abstract: 843,970. Making corrugated tubes; stamping. STANDARD - THOMSON CORPORATION. Dec. 12, 1957, No. 38707/57. Classes 83 (2) and 83 (4). Apparatus for forming flexible tubing comprises a tube to receive a portion of a tubular workpiece, spaced forming plates for closing around a portion of the workpiece outside the tube and adjacent an end thereof, the tube having means to form an external seal with the workpiece, means for applying hydraulic pressure to the tube, said pressure reaching the inner surface of the portions of the workpiece enclosed by the forming plates and by the tube and the outer surfaces of the portion within the tube and said seal, whereby the workpiece is bulged outwardly against the plates to form partial convolutions, and means for completing said convolutions by compressing the portion of the workpiece enclosed by the forming plates towards the adjacent end of the tube while said pressure is maintained. The tube 13 has a bore 13a, sufficient barely to clear the workpiece and a bore 13b of greater diameter and is mounted in a support 20. After a workpiece 41 has been inserted the ends of the tube are sealed by breech caps 36 and 44. Five forming plates 40 are provided and the completed convolutions are received in a longitudinally-reciprocated tube 42 secured within an hydraulic cylinder 16 (Fig. 3). The workpiece is received loosely over a guide tube 46. Between stationary walls 12 and 18 of the apparatus (Fig. 3) are supported a pair of fixed rods 48 having integral pistons 50 accommodated in cylinders 54 forming part of a reciprocable carriage 52. Application of hydraulic pressure to the cylinders 54 and the cylinder 56, which accommodates the piston of cylinder 16, adjusts the longitudinal movement of the tube 42 as required by successive steps in the forming cycle in which the tube 13 remains stationary while the tube 42 reciprocates longitudinally progressively receiving the convoluted sections of the tubing as they emerge from the forming plates 40. The plates are slidable on longitudinal rods (not shown) and the end-plate 60 has an annular channel 61 and a locking flange 62 to engage a matching flange 64 on the tube 13 which also has a similar channel 65. When the plates are opened the flanges disengage to permit the plate 60 to pass over the outside of the tube 13 (Fig. 6). The chuck 63 comprises three meshing wedge-shaped flanged segments 68 secured to radially-movable plates 72 provided with grooves 74 to receive a rib 76 on the cylinder 16. A rubber seal member 78 is secured to the end of the cylinder 16 to provide a hydraulic pressure seal. The workpiece is provided with a removable end-fitting comprising a flanged member 92 for co-operating with the chuck segment 68 and the workpiece is flared outwardly over the ends of filler pieces 94 as at 96 (Fig. 5) before an end-piece 98 is screwed on to the flanged member. The chuck and the end member co-operate to restrain the workpiece during the formation of the initial set of convolutions. In operation, hydraulic pressure is supplied through an inlet 102 to the space 104 within the tube 42. The pressure-fluid fills the workpiece and the space 106 within the tube 13 and expands the workpiece into the channels 61 and 65 and also between the forming plates, as shown in Fig. 1. Automatic or manual controls (not shown) apply fluid pressure to the forming cylinders 54 to operate the cylinder 16 to compress the convolutions and bring the forming plates together. The forming pressure is removed and the plates and chuck are opened before the feed-cycle is initiated (Fig. 6), by applying fluid-pressure to the cylinder 56 to move the end-forming plate 60 over the stationary tube 13 until the seal 78 snaps against the next-to-last newly formed corrugation. The chuck is now closed over the two end convolutions and the cylinder 16 is retracted to its initial position whilst the forming plates are opened longitudinally and realigned on the workpiece before being closed about the next section of the workpiece to be formed with convolutions. U.S.A. Specification 2,796,109 is referred to.