PURPOSE: To control the force at gram unit generated by a piston sliding inside of a cylinder by providing a pulley for supporting the weight of a moving body and a balance weight with the torsion generated in a rotary shaft.
CONSTITUTION: Air is supplied to a piston, which is always shaft-supported by the air supplied from a second and a third compressed air ports 47, 48 of a balance weight 3 on a first and a second air bearing parts 49, 50, from a first compressed air port 46, and the pressure of the air is changed to reduce the weight of a piston 42, which is in proportion to a difference of areas of a large diameter part 43 and a small diameter part 45 of the piston 42, and the piston 42 rises. At this stage, the piston 42, namely, the balance weight 3 rises, and the rising force thereof is transmitted to a pulley 6B through a belt 4, and furthermore, transmitted to a pulley 6A and a belt 8 by the torsion generated in a rotary shaft 5, and the moving body 2 is lowered. With the lowering of the moving body 2, a tool 7 arranged in the tip thereof comes in contact with a material to be machined.
WATANABE HIROYA
YUASA AKIHIKO
