Tool driving or impacting – Automatic control of power operated means – Drive means responsive to condition of advance causing or...
Patent
1997-11-18
1998-11-17
Smith, Scott A.
Tool driving or impacting
Automatic control of power operated means
Drive means responsive to condition of advance causing or...
173193, 173208, 91415, 91519, B25F 500, F15B 1518
Patent
active
058364005
ABSTRACT:
A hydraulic tool having a ram or other working element propelled by pressurized fluid. The tool has a lever which is squeezed to develop fluid force in a pump. The fluid circuitry automatically operates the ram selectively at any one of three operating speeds and hence at three different magnitudes of force relative to the input speed of the lever as it is squeezed. The circuitry includes a principal supply subcircuit in which fluid flows directly from the pump to the ram, thereby establishing a normal speed mode of operation. A high speed subcircuit and a low speed subcircuit each operated by respective pressure responsive valves direct fluid ejected as the ram piston and pump piston advance to the respective rear sides of the ram piston and pump piston. This has the effect of accelerating the ram and operating at reduced force, thereby establishing a high speed mode of operation when resistance against the ram is minimal, and of decelerating the pump piston and operating at greater force, thereby establishing a low speed mode of operation when resistance is relatively high. In a preferred embodiment, the hydraulic tool includes a handle enabling grasping in pistol grip fashion and enabling ready squeezing of the lever.
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Gallentine William
Tupper Myron D.
Siemens Terrance L.
Smith Scott A.
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