Patent GB-783352-A (GB)
Title: Improvements in electric switch-gear for the control of machines
Inventor: FRANCE JOSEPH
IPC: D01H1/20
Filed: 1955-02-22
Abstract: 783,352. Gearing for stopping and starting machinery; friction clutches. T.M.M. (RESEARCH), Ltd. March 20, 1956 [Feb. 22, 1955], No. 5291/55. Class 80 (2). [Also in Groups XXXV and XXXVII] A machine having a number of alternative control stations, such as an electrically-driven textile processing machine, comprises a driving motor (not shown), a clutch having a coil K, Fig. 2, energized to engage it, and circuits connecting the control stations to the clutch coil, the arrangement being such that the machine may be started, stopped and " inched " by the operation of a single push-button A at any of the control stations. The clutch coil K, Fig. 2, is supplied with direct current from terminals D, E when a switch 15, 16 is closed on energization of a relay R1. Closing the switch 15, 16 simultaneously opens a switch 13, 14 through which current is supplied to a time-controlled relay R5. On closing the switch 15, 16, current is supplied through a rheostat P to the clutch coil K, the rheostat restricting the current flow to ensure a gentle take-up of the drive through the clutch. A short while after the switch 15, 16 is closed and the switch 13, 14 opened, the time-controlled relay R5 becomes de-energized and closes a switch 11, 12 to shunt out the rheostat P, so that the amount of current flowing through the coil K is increased for full clutch engagement. The relay R1 is in a separate circuit fed with alternating current from terminals B, C. With the clutch coil K de-energized, current flows through the terminal B to switch contacts 8, 9 and a relay R4, to close a circuit through a switch 1, 3, and from the relay R4 through closed switch contacts controlled by a relay R2 to the terminal C. On depressing any one of the press-buttons A, a circuit is completed through the switch 1, 3 and a relay R3 to close two switches 4, 5 and 6, 7. This completes a circuit through the terminal B, the switch 4, 5, the relay R1, and the already closed switch 17, 18 to the terminal C so that the relay R1 operates the switches 13, 14 and 15, 16 to energize the clutch coil K as described above. Simultaneously, the relay R1 has broken the circuit through the switch contacts 8, 9 and made a circuit through the switch contacts 8, 10, so that the relay R1 is now energized through a circuit comprising the parts B, 8, 10, R1, 17, 18, C. Breaking the circuit through the contacts 8, 9 de-energizes the relay R4 which operates the switch 1, &c. to break the circuit through the contacts 1, 3 and make it through the contacts 1, 2. On releasing the push-button A, the circuit through the switch contacts 8, 10 holds the relay R1 energized. When a push-button A is again operated, a circuit is completed from the terminal B, through the push-button, the switch contacts 1, 2 and a relay R2 to the terminal C. Energization of the relay R2 opens the switch contacts 17, 18 in the circuit through which the relay R1 is fed, which accordingly is de-energized and restores the switch contacts 15, &c. to their initial condition. This breaks the circuit through the clutch coil K to. disengage the clutch. On releasing the depressed push-button A, the relay R2 is de-energized to close the switch contacts 17, 18 and complete a circuit through the terminal B, the switch contacts 8, 9, the relay 4 and the switch contacts 17, 18 to the terminal C. Energization of the relay R4 breaks the circuit through the switch contacts 1, 2 and closes it through the contacts 1, 3. The circuit is then pre-set to cause clutch engagement on depression of a push-button A. To "inch" the machine, one of the pushbuttons A is repeatedly pressed and released. A friction clutch for use with this control circuit has a stationary coil 112, Fig. 3 (coil K), on a sleeve 110 fast with the frame 114 of a driving motor. The motor shaft 111 has fast at its end a bushing 115 carrying feather keys 116 by which it is rotatably connected to a clutch member 117. An annular surface on the clutch member 117 can be engaged by a clutch lining 118 secured to a ring 119 adjustably mounted on a driven clutch member 120. A V-belt pulley 121 is secured to the clutch 120. Energization of the coil 112 (coil K) moves the clutch member axially into engagement with the clutch lining 118 against the bias of disengaging springs 122.