GB680929A - Improvements in or relating to automatic control apparatus and systems for repetitive operations - Google Patents

Abstract

680,929. Control of motors. WALKER & SON, Ltd., T. March 7, 1951 [March 7, 1950], No. 5717/50. Class 38 (iii) [Also in Groups IX and XIX] Relates to means for automatically causing the termination of a repetitive operation of apparatus such as machinery after a part of the apparatus has executed a predetermined displacement, and for initiating a succeeding operation that is to be terminated after the said part has executed the same or a predetermined different displacement. In Fig. 2 a differential gear 100 has one element 102 coupled to a part of the machine which is under control through a worm 25, and a second element 104 is coupled to a reversible electric setting motor 2 Fig. 3, of the capacitor type through a worm 26. A third element of the differential 100 is cascaded through shaft 115 with the first element 203 of another differential gear 200 which has its second element coupled to a pre-setting handle 332 and its third element associated [with shaft 215 and cam-operated switches 230, 250. A cam-operated switch 130 is associated with the shaft 115 of the cascade connection. The switches 130, 230, 250, are operated by pairs of cams, one cam of each set being driven at a multiple of the speed of the other one of the pair, and the switches are actuated when each cam in a pair is in a predetermined position relative to the other. In order to pre-set the apparatus for a run of pre-determined length the handle 332 is unlocked and rotated until the appropriate indication is shown by pointers 338, 339, The rotation of the handle drives wheel 204, the wheel 203 being locked because the machine and setting motor are stationary. The cams 241, 242; are thus moved to close contacts 254, 252. On release of the handle 332 it is locked, and, upon closure of contacts 71, 72, of switch 70 which is interlocked with the handle, the setting motor runs until switch 230 closes contacts 232, 233, so operating relay 40 to stop the setting motor which hunts before finally coming to rest. The cams which operate the switch 130 are now in a desired predetermined position. The closure of switch 46 allows starting of the machinery so that the wheel 102 is rotated, the wheel 104 being held steady since the setting motor is at standstill. The shaft 115 thus drives wheel 203, the wheel 204 is locked, and the shaft 214 is rotated to displace cams 221, 222, and 241, 242. The displacement of the machine is indicated by pointers 113, 114. When the cam-switch 130 is operated it opens the switch 46 to stop the machine. Reclosure of the switch 45 again starts the setting motor which is driven to its predetermined limit whereupon the system is re-set and conditioned for starting on a similar run unless the pre-setting handle 332 has been re-adjusted. A solenoid-operated ratchet counter 49 advances one step each time the operating-coil 42 of relay 40 is energised. This system may be applied to the control of spinning frames or machines for yarn doubling, the machine being stopped after spinning or doubling a chosen length of yarn as measured by the number of revolutions executed by a roller or shaft of the machine to which worm 25 is coupled. When applied to a wire drawing machine, for example, the resetting of the apparatus by means of the motor 2 involves wastage of time and the modification of Figs 4, 5, (not shown), is used. In this modification, the wheel 102 is connected to the machinery by means of reversible transmission comprising, for example, an electrical position transmitter having delta-connected windings which are connected to the windings of a receiver through a reversing switch. This reversing switch is automatically actuated at the end of each operation of the machine so that the machine makes successive equal runs with small time delay between each operation, and the setting motor is not brought into use unless it is desired to alter the length of run. Specification 934/99, [Class 40], is referred to.