| 摘要 |
<p>An air driven hydraulic pump having an excellent responsiveness at the time of quick opening of a pilot air supply valve. The air driven hydraulic pump comprises a plunger pump mechanism (10), an air cylinder (20) for driving the pump mechanism, and an air supply/exhaust switch-over mechanism (30) which automatically switches over between an air supply state of supplying pressurized air to an air-operated chamber (23) of the air cylinder and an air exhaust state of exhausting pressurized air out of the air-operated chamber (23). The air supply/exhaust switch-over mechanism includes a pilot air supply valve (41) and a pilot air release valve(42) for switching a movable valve body (35) between the air supplying position and the air releasing position. The pilot air supply valve consists of a guide shaft (38) which is an integral part of a plunger (15) of the pump mechanism, a cap member (39) slidably fitted on the guide shaft, and the movable valve body. When a piston comes close to the advance limit position, the cap member is relatively moved by a set distance (G) with respect to the guide shaft to quickly open the pilot air supply valve.</p> |
