FLUIDIC CONTROL CIRCUIT FOR PRESSES

摘要

1,216,435. Fluid logic and switching circuits. E. W. BLISS CO. April 3, 1969 [April 10, 1968], No. 17696/69. Heading F1P. A fluidic control circuit for alternatively actuating a clutch mechanism and a brake mechanism of a press comprises a gate 9NOR having respective output lines 01, 02 connected to the clutch and brake mechanisms and having an input line C 1 connected to the output of a first AND gate 50 having two or more inputs C 2 , C 1 the former being fed by a feedback loop through 64 and 7NOR from the output O 2 of said AND gate 50 (8NOR) and the latter input C 1 being provided with an input signal whilst means 64 is provided for interrupting the signal to at least one input C 2 of gate 50. The press which is crankshaft driven may run continuously or on a single stroke basis or by inching through a 360 degree crank rotation. It is preferably stopped at the top of its stroke but at any position in an emergency. To start the press a momentary C 2 input at 9NOR gate is provided by outlet 01 of 1 AND gate 24 which outlet is obtained by momentarily pressing spring-returned valves 16, 18 in parallel branches 20, 20a of the main air supply line thereby providing a momentary C 2 input at gate 24; there being a continuous C 1 input at 24 from a flip-flop valve 22 having its input C 2 connected to air line 20a. A continuous input C 1 is now applied to 9NOR gate by the output O 2 of 8NOR gate which together with 6 and 7 NOR gates from a latch-in AND gate 50. In order to provide 02/8NOR there must be a continuous input at both 6 NOR and 7 NOR. Continuous input C2/7NOR is provided by the feedback loop 46b from 02/8NOR passing through an emergency stop valve 64 and the required continuous input at C3/6NOR is provided by a seal-in AND gate 48 made up of NOR gates 3, 4 and 5 (52, 54, 56). In operation C1/4NOR receives 1 AND/01 output (start signal) thus producing an 01 output at 4NOR and no input at C 2 /5NOR. Also there is established by means of jet sensor limit switches 32, 34 and NOR gates 38, 43 an input at either C 1 or C 2 of 3NOR thereby providing an 01/3NOR output and no input C1/5NOR. With no input at either C 1 or C 2 of 5NOR an output is maintained in a line 58 leading to C3/6NOR and connected by a line 58b passing through a top-stop valve 65, 66 to C2/4NOR thereby connecting the output thereof to 01 i.e. atmosphere. Limit switch 34 provides a signal at inlet C 1 of 1NOR except for a short time at 180 degrees crank-shaft position when a cam 41 on the crank-shaft obstructs a gap 1, 2 in the switch circuit. Limit switch 32 provides a signal to C 1 of 2NOR except when gap 1, 2 of switch 32 is obstructed by a cam 40 at between 90 degrees and 270 degrees. To stop the press at the top of its stroke button 66 is pressed to terminate the C 2 input to 4NOR. This shifts the output at 5NOR from 02 to 01 thereby terminating the C 3 input to 6NOR. The C 2 input at 6NOR is maintained since in the absence of a C 2 input at a flip-flop 62 the output of the latter remains at 01, but at the 180 degrees crank-shaft position there is a C 2 input at 62 shifting the output thereof to 02 where it remains and terminates C 2 input to 6NOR, and when the crank-shaft reaches the 2706 position the input C 1 to 6NOR is cut off and the press is stopped at the top of its stroke.