Patent ID: 6110045
Filing Date: 2000-08-29
Classification: B25B,Y10S

Abstract:
A hydraulic torque impulse generator for a power wrench having a rotation motor, said hydraulic torque impulse generator comprising:a drive member adapted to be connected to the rotation motor, said drive member having a hydraulic fluid chamber with two opposite end walls;an impulse receiving output member extending coaxially into said hydraulic fluid chamber, said impulse receiving output member being coupled to said drive member via a hydraulic pressure pulse generating device dividing said hydraulic fluid chamber into at least one low pressure section and at least one high pressure section; anda variable volume accumulator chamber connected to said hydraulic fluid chamber via a communication passage, said variable volume accumulator chamber including a yieldable member;wherein:i) said accumulator chamber is formed partly by a depression in one of said opposite end walls of said drive member and partly by a closure rigidly secured to said end wall,ii) a bore extends from outside said end wall (30), said bore being adapted to receive at least partly said closure,iii) said depression is formed at a bottom of said bore, and an annular shoulder is formed around said depression,iv) said yieldable member comprises an elastically deflectable membrane which is secured by clamping between said closure and said annular shoulder, andv) said communication passage is arranged to connect said accumulator chamber to said at least one low pressure section so as to prevent pressure impulses repeatedly generated in said at least one high pressure section from reaching said accumulator chamber.