To provide a compact and lightweight valve driving device, for which no restriction on an installation place and no installation of a carriage is required, by using compressed air or instrument air at a comparatively low pressure as power.
In a valve driving device, in which a hydraulic type operation machine 2 is actuated when hydraulic oil whose pressure is increased by feeding instrument air and the like into a booster 1 is fed out, a large diameter piston 18 is inserted into a cylinder 17 in the booster 1, a small diameter cylindrical column part, 19 concentrically arranged on one side of the piston 18 penetrates an end wall 22 sealingly so as to be protruded to the outside. When the hydraulic oil is filled in one side 20 of the cylinder 17 while instrument air and the like is fed into the other side 21, the hydraulic oil, whose pressure is increased in inverse proportion to the operation area ratio between the air and the oil working on the piston 18, is fed out, while an air-oil booster 5 is connected to the one side 20, and the booster 1 is restored when the hydraulic oil, whose pressure is increased by feeding the instrument air and the like to the air-oil booster 5, is fed to the one side 20.
SATO KOJI
FUKUNAGA AKIO
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