Patent ID: 6546815
Filing Date: 2003-04-15
Classification: B25B

Abstract:
A method for detecting a wobbling in a controlled tightening of a hand-held powered wrench comprising a rotary member which, after running freely, starts decelerating when it provides a hammering force to a driven shaft side and, after the end of deceleration, rebounds and runs freely again,wherein there is provided detecting means to detect variation in rotation velocity of the rotary member and a rotation angle of the same, wherein on the basis of the variation in the rotation velocity and the rotation angle detected by the detecting means, an angle obtained by subtracting a cumulative total of the rotation angle in the rebounding direction from a cumulative total of the rotation angle in the tightening direction is detected and accumulated as a total rotation angle (P) and a rotation angle formed at the hammering in the course of deceleration is detected as &Dgr;H and accumulated, and a preset design angle Pd for hammering corresponding to the number of hammerings provided until the end of the tightening work is accumulated, and wherein a wobbling angle is calculated from the following Equation: A wobbling angle=Pâˆ’a cumulative total of Pdâˆ’a cumulative total of &Dgr;H, where Pd is a design value of the powered wrench, indicating an angle corresponding to 360Â°/m for the case of the m number of hammerings per rotation of the rotary member.