Abstract: A modular rake shaft assembly is provided for attachment to and use the support frame of a bowling pin setting machine which includes three components namely, two rake arms interconnected by a tubular member. Each arm has a transversely extending stub shaft at one end. Each stub shaft has an opening on its outer end and a flange on its inner end. The tubular member has flanges at each end for connection to the respective stub shaft flanges. Each arm is tubular, but is deformed by a longitudinal groove along one side to increase the strength of the arms against bending. An angle member is also mounted on each arm to serve as a stop during movement of the arms and to further minimize the likelihood of breaking due to repeated striking of the arms against the stops. The flanges each have spaced lobes spaced unequally to accommodate swinging movement of the rake shaft assembly with respect to the support frame.

Abstract: An electric switch and signal output device for use in fluid systems. A light source and photosensitive pickup are disposed in aligned positions in a cross bore of the switch body at opposite sides of a main bore that reciprocally receives a piston element. If fluid subjected to differential pressures is introduced to the main bore at one side of the piston or if fluid is introduced to opposite sides thereof, pressure pulses or changes in differential pressure in the fluid system cause movement of the piston away from or toward an interfering position with respect to the light path between said light source and pickup. Incident light at the pickup, which may be a photocell resistor, provides an output electrical signal change that is usable for control, position indicating, counting or logic purposes. The actuation sensitivity is changed by use of different weight pistons and/or by use of adjustable resilient means.