Patent ID: 8905154

Claim:
An impact torque-adjusting device in a hydraulic torque wrench, comprising: a liner having a liner lid and a fluid path formed in said liner lid; a rotor for rotating said liner; a main shaft disposed inside of said liner, said main shaft having a blade insertion part and said main shaft housing having two directions of rotation; blades provided in said blade insertion part inside of said liner, wherein the inside of said liner comprises a high-pressure chamber and a low-pressure chamber in operation, and wherein said high-pressure chamber communicates with said blade insertion part; a working fluid path that communicates with the inside of said liner; a valve body disposed in said working fluid path and biased in a direction of opening said working fluid path, said valve body having a rear back side; and an oil chamber on said rear back side of said valve body, said oil chamber communicating with said blade insertion part of said main shaft through said fluid path formed in said liner lid; wherein said valve body is arranged such that said working fluid path is narrowed in response to an elevation of the pressure of the working fluid in said blade insertion part of said main shaft along with an elevation of the pressure of the working fluid in said high-pressure chamber in both of the two directions of rotation of said main shaft.