Abstract: In combination with a plunger operated device such as a standard pushbutton limit switch (2), an auxiliary rotary actuator (4) having an operating arm (36) attached to a rotary cam(40) having a convex conical cam surface (40c) in contact with a complementary concave conical cam surface (42a) of a reciprocating linear motion cam follower (42), with the cone axes (40d, 42c) being in alignment and offset from the axis of rotation (40e) of the cam. A switch plunger (12) abutting shaft (38) is threaded in a bore (42b) in the cam follower (42) and has a smooth round shaft portion (38b) slidingly guided in a smooth bore (40b) in the cam to be adjustable up or down by a screwdriver slot (38c) in its upper end accessible when the actuating arm (36) mounting screw (46) is removed.