The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 17, 1998
Filed:
Nov. 18, 1997
Myron D Tupper, Boring, OR (US);
William Gallentine, Hood River, OR (US);
Other;
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.