Patent ID: 7453225
Filing Date: 2008-11-18
Classification: B25B,Y10S

Abstract:
1. An impulse nut runner, comprising: an output shaft, a motor with a rotor, an impulse unit connecting the motor to the output shaft and including an inertia drive member rigidly connected to the rotor of the motor, a rotation detecting device comprising a ring element rigidly secured to the drive member and magnetised with a number of magnetic poles equidistantly distributed along a periphery of the ring element, and a sensing device mounted approximately to the ring element and arranged to deliver electric signals in response to passing of said magnetic poles at rotation of the drive member, wherein said sensing device comprises four Hall-elements each delivering a sinusoidal electric signal at rotation of the drive member, and wherein said Hall-elements are disposed in two pairs, and the Hall-elements in each pair are arranged to deliver signals with a 180 degrees phase lag relative to each other and with a 90 degrees phase lag relative to the Hall-elements of the other pair.