Patent GB-359395-A (GB)
Title: Improvements in or relating to apparatus for drawing metals
IPC: B21C1/16
Filed: 1930-05-20
Abstract: 359,395. Drawing. WHITE, A. E., 5, Quality Court, Chancery Lane, London.- (Aluminium, Ltd. ; 22, Canada Building, Toronto, Canada.) May 20, 1930, No. 15541. [Class 83 (iv).] Grippers &c.-The drawhead of the draw bench shown by joining together Figs. 1a, 1b and 1c is located below the endless drawing chain 38 so as to leave a clear space underneath to allow the drawn tube to drop freely therefrom when released automatically and so allow the drawhead to be returned immediately by the pull of the cable 84. The winding drum 85a is continuously rotated but has a slipping periphery to allow the cable 84 to unwind when under the greater pull exerted by the drawhead when coupled to the chain 38. The tube b is drawn over a bulb and through a die in the die holder 30a by means of the endless chain 38 to which the drawing head is coupled and uncoupled automatically by its hook 56. In the machine there are two drawheads arranged side by side and the drawheads are operated alternately. To start, the operator pushes back the bulb rod 100 until its abutment 133, Fig. 17, engages abutment 138 at the end of plunger 137 and threads on it a fresh tube b from rack bars 44 and then inserts the swaged down end through the die into the jaws 70 of the open tongs of the drawhead. He then admits pressure fluid through inlet 82, Fig. 1c, to top of cylinder 77 which rocks hook 56 up to engage the moving chain 38 thereby starting drawing the tube to the right. When the drawhead starts to move its left hand part 50 is held back by the dashpot plunger 91 thus closing the tongs on the tube end. After the tongs have closed the whole drawhead moves pulling the dashpot plunger 91 out of its cylinder 88, until member 107, Fig. 19, on rod 104 coupled to stem 103 rocks valve lever 124 to right thus admitting pressure fluid through pipe 127 to plunger 137 which moves the bulb rod up to fixed position in the die for drawing. This position is adjustable by hand wheel 117 moving the crosshead 118 to determine the prior place of stoppage of member 107 thus determining the time of opening the valve 126 to allow fluid pressure into the bulb rod cylinder. The drawhead continues its movement to the right until the dashpot plunger fouls the end of its cylinder 88 so that the latch 95 swings down to disconnect the drawhead from the plunger and allow the draw head to continue on until the end of the tube emerges from the die with a jerk. This jerk moves the front part 50 of drawhead in its slots relative to the rear part 49 which opens the tongs and allows the tube to fall down the skids 40 into the trough 42. By the time the jerk is communicated to the rear part 49 which then moves ahead of the chain 38 so that the hook 56 drops out of engagement with the chain, the cable 84 which has been uncoiled from its drum during drawing is now able to return the drawhead to the left. Near the end of the return of the drawhead the pad 98 on the front part 50 strikes the head 91 of the dashpot plunger and pushes it into its cylinder with cushioning effect. The tongs are then held open by the pull of the cable 84 on the part 49 opposed by the dashpot pressure on the part 50. The latter part of the return of the drawhead also allowed the valve lever 124 to spring back to exhaust the left end of bulb moving cylinder 136 to atmosphere and allow pressure fluid to enter the other end of cylinder 136 through inlet 139 and moving the plunger 137 to the left so freeing the rear end of bulb rod 100 so that it can be pushed back by the operator.