GB972049A - Electric control circuits for fluid pressure operable clutches - Google Patents

Abstract

972,049. Controlling clutches. I.G.E. CONTROL EQUIPMENT Ltd. May 22, 1963 [June 5, 1962], No. 21613/62. Heading F2L. [Also in Division H2] In an automatic machine of the kind incorporating a switch 7 operable by a part of the machine as the latter nears the end of a cycle of operation to prevent the machine starting a further cycle of operation unless an attendant operable switch associated with an electric control circuit is re-operated, in order to permit " inching " of the machine without shortcircuiting of the safety circuits forming part of the control circuit, a manually operable changeover switch 8 is provided which in the full-line position shown in Fig. 3 connects the machine operable switch 7 in the circuit, and in the dotted-line position connects a fluid-pressure operable switch 5 into the circuit. The circuit controls a pneumatically operated friction clutch having a servo 4 supplied by an air line 1 under the control of a valve 2 operated by an electromagnet 3, and the switch 5 is tapped intermediate the servo by way of a flow regulator 6. The electromagnet 3 is controlled by the circuit of Fig. 3 and is normally de-energized when the switch 7 opens at the end of a cycle of operations. When the switch 8 is operated to include the switch 5 in the circuit the clutch is engaged for as long as it takes the pressure operable switch 5 to open. This period is adjustable by altering the setting of the flow regulator. A normally open switch 9 may be provided in parallel with the switch 5 so that the machine may be run under manual control for longer periods than provided for by the switch 5.