PUSHBUTTON SWITCH

PROBLEM TO BE SOLVED: To surely perform an emergency stop of a load by pressing a pushbutton to transmit the pressure to a push rod through a spring and at the same time moving the push rod when spring force exceeds a predetermined value and after moved, preventing the push rod from returning. SOLUTION: When a pushbutton 2 is pressed down in order to make an emergency stop of a load, a coil spring 8 and a return spring 20 are instantaneously compressed in the bottom surface of a rotary cylinder 4. When the pushbutton 2 is sufficiently pressed down and spring force stored in the spring 8 exceeds a predetermined value, the projecting part 51 of a pushing rod 5 climbs over the projecting part 61 of a guide cylinder 6, and the moving contact of a switch part 10 is driven to open while climbing thereover to stop a load. Since the movable quantity of the moving contact is set larger than the sliding length in the axial direction of the projecting parts 51, 61, the push rod is made to abut on a stopper and is stopped after the projecting part 51 climbs over the projecting part 61 and slightly goes beyond. When a hand is released from the pushbutton 2, the projecting part 51 is engaged with the projecting part 61 through a spring 20 to come to a standstill. The return of the pushbutton to the original state is performed by rotating the pushbutton 2 about its axis, removing the engagement of the projecting parts 51, 61, returning the push rod 5 to the original state by the restoring force of the spring 20, and removing the hand from the pushbutton 2.