PURPOSE: To control smoothly and effectively by a method wherein a pushtype simple switch means is put ON or OFF by a cam member, reciprocated and slid intermittently under a frictional resistance caused by a predetermined energizing means.

CONSTITUTION: A pivot member 90 effects alternately pushing and releasing of the input unit 68 of a microswitch 66, and is pivoted to the reverse direction intermittently in accordance with the reciprocating motion of a mounting bracket 16, thus, pushing and releasing of the input unit 68 of the microswich 66 is effected by the reciprocating pivot of the pivot member 90. The pivot member 90 is pushed against the stepped surface of a boss 100 by a disc spring fixed by a screw 104 and is kept effectively by a frictional resistance caused by the disc spring, thus, the switching operation of the microswitch 66 is effected smoothly and stably by the pivot member 90. The structure is simple, the cost is inexpensive, troubles are reduced and the durability thereof may be improved.