Fluid-operated wrench
Patent 4974476 Issued on December 4, 1990. Estimated Expiration Date: 
July 29, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 29, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesUniversally usable hydraulic wrench for simultaneously tightening or loosening two threaded connectors or for tightening or loosening a single threaded connector with a greater force Hydraulic wrench Joint connection for space framework, made of rods and joint members Fluid-operated wrench Fluid operated wrench Patent #: 4706526 InventorApplicationNo. 226407 filed on 07/29/1988US Classes:81/57.39Step by stepExaminersPrimary: Smith, James G.Attorney, Agent or FirmForeign Patent References
International ClassB25B 013/00AbstractA fluid-operated wrench as comprising a cylinder-piston unit with a cylinder having a guide and a piston performing an active stroke in one direction and a reverse stroke in an opposite direction, an engaging member arranged to engage a threaded connector to be tightened or loosened, and formed so that its one circumferential portion engages the threaded connector while its remaining circumferential portion is open, and a reaction member arranged to abut against an adjacent object and spaced from the engaging member in the direction of the active stroke so that a reaction force during the active stroke tends to push the guide onto the engaging member and to reliably hold the latter on the threaded connector. | |
