Pneumatic/hydraulic remote power unit

Apparatus for supplying high pressure hydraulic fluid to a hand tool comprising:

• an intensifier having a first relatively large diameter pneumatic cylinder and a second relatively small diameter hydraulic cylinder containing hydraulic fluid, a first piston operatively positioned in said pneumatic cylinder and mechanically coupled to a second piston operatively positioned in said hydraulic cylinder;
• switching means connectable between a source of pressurized air and said pneumatic cylinder, said switching means having a first air outlet port connected to a first end of said pneumatic cylinder and operative in a pressurizing mode for supplying air pressure to drive said first piston in a direction to pressurize the hydraulic fluid and having a second air outlet port connected to a second end of said pneumatic cylinder and operative in a depressurizing mode for supplying air for retracting said first piston and depressurizing the hydraulic fluid;
• and
• pressure responsive means coupled for sensing pressure of the hydraulic fluid and responsive thereto for affecting switching of said switching means from said pressurizing mode to said depressurizing mode when the pressure of the hydraulic fluid reaches a preselected value.

A method of operating a control for actuating a remote tool, the control comprising a piston having a pair of opposed effective areas respectively subjected to air and hydraulic pressures, the method comprising the steps of:

• selectively applying the air pressure onto one of the opposed effective areas of the piston;
• moving the piston in response to the selectively applying step;
• creating a hydraulic pressure acting on the other of the opposed effective areas in response to the piston movement during the moving step and actuating the remote tool in response to the hydraulic pressure established during the creating step;
• sensing the hydraulic pressure created during the creating step;
• and
• exhausting the air pressure acting on the one opposing effective area when the sensed hydraulic pressure attains a preselected value.