Patent GB-763357-A (GB)
Title: Improvements in or relating to apparatus for parting-off predetermined lengths of a helical spring
Inventor: STEGMANN ERNST
IPC: B21F35/00
Filed: 1954-01-15
Abstract: 763,357. Making springs. STORENUND MASCHINENFABRIK E. SCHENKER AKT.-GES. Jan. 15, 1954, No. 1265/54. Class 83 (2). [Also in Groups XXIII and XXIX] Springs are formed by winding continuouslyfed wire into a helix, which rotates and moves forward in a similar manner to a screw, and cutting the helix into lengths by a tool, e.g. a grinding disc, moving with the spring to form flat surfaces at the ends of the springs. An electric motor 105, Fig. 6, drives a main pump 103 and through a continuously-variable speed gear 106 preset in accordance with the rate of feed of the wire to the winding-machine, not shown, drives a variable output pump 108 whose output is regulated by an electromagnet 109 controlled by a feeler 134 in the winding-machine and responsive to the pitch of the spring A. When the spring A passing into the cutting-machine, Figs. 1, 3, engages a feeler 98 on a carriage 13, a valve 110 is actuated to pass the output of the pump 103 through the pump 108 to an hydraulic motor 20 which drives the carriage 13 in the same direction as the spring A. The output of the motor 20 is regulated by an electromagnet 21 controlled by a feeler 136 in the winding-machine and responsive to the diameter of the spring. Slight differences between the speeds of the carriage 13 and the spring are counteracted by a roller 100 mounted on the carriage 13 and movable axially by the spring to control through a potentiometer and an electromagnet 119 a valve 118 adjusting the input to the motor 20. On the carriage 13 for supporting the spring are a fixed support 51, two pairs of movable supports 49, 52 in brackets 57 pivoted on a rod 59, and a spring-loaded support 54 engaging the end turn of the spring A. When a feeler 99 on the carriage 13 adjacent the grinding disc 37 engages a turn of the spring A, it operates a switch 91 and a contact 92 to actuate valves 121, 131 respectively, whereupon the output of pump 103 is fed to a movable cylinder 35 secured to a slide 33 carrying the cutting disc 37. When the turn rotates away from the feeler 99, the contact 92 opens to release valve 131. Thus the grinding disc 37 is fed forward only when the spring turn is in a position to be cut. The speed of movement of the slide 33 is varied as the cutting proceeds by a cam 129 on the carriage 13 which adjusts a valve 126 in the pipe supplying the cylinder 35. Just before the spring is severed the movement of the slide 33 operates switches 89 and 90 actuating a magnet 66 to release a member 65 locking the brackets 57 in position and a valve 123 causing a piston 62 to swing the brackets 57 and the associated supports 49, 52 clear of the spring. At the same time a cam 85 swings the support 54 away from the end of spring which drops clear. The brackets 57 engage a switch 70 which releases valve 123 whereupon the piston 62 and the brackets 57 are returned to their operative position. Continued movement of the slide 33 opens the switch 91 which releases the valve 121 to reverse the slide 33. During return of the slide 33, switch 89 is opened so that the member 65 locks brackets 57 and switch 91 is closed to operate the valve 121. Movement of the carriage 13 continues until a stop 28 on the main frame 10 opens the switch 97 to release the valve 110. The carriage 13 is driven back relatively quickly by the motor 20 which is fed by both pumps 103, 109 in parallel until the oncoming spring A again engages the feeler 98 whereupon the cycle of operations is repeated. If the carriage 13 over-runs in either direction one of switches 29, 31 disconnects the electric motor 105.