Patent GB-608063-A (GB)
Title: Drawbench
IPC: B21C19/00
Filed: 1946-02-14
Abstract: 608,063. Drawing. AETNA-STANDARD ENGINEERING CO. Feb. 14, 1946, No. 4666. Convention date, Feb. 23, 1945. [Class 83 (iv)] [Also in Group XL (b)] In a draw-bench for tubes or bars having a series of work-discharging arms spaced along the bench and simultaneously movable into and out of operative position transversely across the bench, the means for moving the arms is controlled so that they may be moved into the operative position only after the carriage, during its working traverse, has passed all the said arms. The draw-bench comprises a die stand 16 and a carriage 14 having work-gripping tongs 15 and a hook 18 for engaging the endless chain 17 driven by an electric motor 19 through gearing. After a working traverse, the work falls on to a series of arms 25, 26, 27 and 28 having inclined upper surfaces down which the work rolls clear of the bench. The arms are then swung into a position alongside the bench and the carriage is returned by a second motor 21 with high- and low-speed windings. Each arm is pivotally mounted in a bracket secured to the side of the draw-bench so as to be movable in a horizontal plane and is moved into and out of operative position by means of a depending spindle formed at its lower end with teeth engaging a rack which may be reciprocated by pistons of different sizes operating in cylinders 44, 45 respectively, the corresponding cylinders of all the arm-actuating devices being connected by pipes 73 and 75 respectively to a source of pressure fluid 74. A solenoid-operated valve 76 is inserted in the pipe 75. When the solenoid is energized, pipe 75 is connected to atmosphere and the pressure within cylinders 44 moves the arms into operative position across the draw-bench. When the solenoid is not energized, pressure fluid is supplied to all the cylinders and the greater force exerted on the larger pistons causes the arms to be swung clear of the bench. If comparatively short tubes or bars are being drawn, the last arm 28 may be fixed in the inoperative position as shown in Fig. 1 by manual shut-off valves 71, 72. A movable stand 85 containing a light source 87 and a photo-electric cell 88 is positioned beside the bench beyond the. last of the arms 27 which is to be used. When the carriage 14 passes this stand during its operative traverse, a mirror 92 on the carriage causes light from the source to be reflected on to the cell to operate a contactor 91 and so energize the solenoid of the valve 76 and the arms are moved into the workdischarging position. Operation of a manual switch 95 in the circuit of the contactor 91 serves to move the arms to the inoperative position ready for the return movement of the carriage, and this movement of the arms allows light from a source 96 to fall on a photo-electric unit 97, thus completing a circuit between conductors 98 and 99. If another photo-electric unit 104 is also energized and a contactor 102 is de-energized, circuits will be closed through contacts 113, 114, 115 and the high-speed windings of the motor 21 and the carriage will return towards the die at a high speed until a flag on the carriage interrupts the passage of light between a source 109, a mirror 111 on the side of the bench and the photo-electric cell of the unit 104. This effects the deenergization of a contactor 100 and the breaking of the contacts 113, 114, 115 in the circuit of the high-speed windings and the energization of the contactor 102, thus making the circuits through the low-speed windings of the motor 21. When the flag on the carriage interrupts the passage of light to another cell 133, the motor 21 is stopped and the apparatus is ready for a fresh drawing operation.