GB904120A - Improvements in or relating to control systems for machines which are adapted to perform a plurality of operations sequentially - Google Patents

Abstract

904,120. Sequential switching systems. GENERAL ELECTRIC CO. Ltd., HARRIS, E. S., and WEST, G. M. May 13, 1960 [Feb. 13, 1959], No. 5134/59. Class 38 (4). A sequential control system for a machine comprises a number of identical cold cathode tube circuit units 1-5, each controlling an hydraulic valve through a mercury relay, and a number of other identical bi-stable cold cathode tube circuit units 10-15, the units being connected in an arrangement, so that when a circuit is set up by manual switches 17-19, 23, a single or succession of sequences is performed. The arrangement illustrated controls the operations of an injection moulding machine, unit 1 opening and unit 2 closing a die, unit 3 retracting and unit 4 advancing a plunger, the unit 5 controlling an hydraulic pump. Closure of a manual switch 23 causes through the unit 2 the die to be closed which closes limit switches DCA, DCB energizing through the former a timing circuit 6, and the unit 13, the latter triggering unit 4 causing the machine plunger to advance which opens contacts PI and PRA, the latter energizing the pump unit 5, and timing circuit 9, which subsequently de-energizes the unit 5. The timing circuit 6 then energizes the unit 11 which in turn energizes unit 12 which de-energizes unit 13, also through unit 3 retracts the plunger. Contacts PRA are then returned to the position shown, thus energizing unit 10 which initiates operation of timing circuit 7 which eventually opens the die through unit 1. To perform a succession of operations contacts 16 are closed and 17 opened and for double shot operation contacts 18 are closed and 19 changed over. By a re-arrangement of the circuit the apparatus is stated to be suitable for controlling the operations of a broaching machine. Specificwtions 872,490 and 904,119 are referred to.