GB1176095A - Method of and Apparatus for Starting a Machine Line. - Google Patents

Abstract

1,176,095. Clutch control systems. L. SCHULER G.m.b.H. 31 July, 1968 [1 Aug., 1967], No. 36539/68. Heading F2L. [Also in Division G1] In a method of starting cyclically operating machines required to work synchronously in predetermined phase relationships to one another the starting of each machine is initiated when the point in its cycle at which the machine is resting is appropriately in advance of its correct phase relationship having regard to the starting behaviour of the machine for the latter to drop into synchronism on reaching its operating speed. Presses 4 are operated with a phase difference at 45 degrees between presses and are driven by a control motor 1 via shaft 2. The motor 1 may be replaced by the drive shaft of a control machine for the press line, e.g. an eccentric shaft of the control press. The shaft 2 drives synchros 3, each adjusted to give the required phase difference and each driving a rotating brush set 5 over a commutator 7 having contacts 6. Each contact 6 is connected to a contact of a second commutator 8 over which a brush set 9 rotates, the latter being rotated synchronously with the ram drive and synchro 10. When a predetermined voltage is achieved in line 11 and circuit 12 a starting signal acts on a control means 20, e.g. a coupling, which is interposed between a drive motor 18 and the press. The voltage may be adjusted by potentiometers 13 and a tachogenerator 19 rotating with the control motor 1 feeds a voltage corresponding to the speed of rotation to the circuit 12. The signals produced by synchros 10 have a voltage varying with the phase difference or the phase difference could be signalled by the duration of a pulse or by the frequency of an alternating current. Operation.-When brush set 5 runs on a contact 6 corresponding to the contact on the commutator 8 on which the brush set 9 is standing a circuit 14 operates a relay 15 which closes a normally-open switch 16 to close the synchro supply circuit 17. Since brush set 5 is 90 degrees in advance of synchro 3 the latter has a phase difference of 90 degrees in relation to brush set 9 and synchro 10 and this causes a maximum voltage in line 11 which decreases as the position of synchro 3 approaches that of synchro 10, the starting signal being initiated when the voltage has decreased to the predetermined value.