Patent ID: 6341533
Filing Date: 2002-01-29
Classification: B25B

Abstract:
A torque impulse delivering power tool for tightening a screw joint to a predetermined torque level by delivering a plurality of torque impulses, said power tool comprising:a rotation motor, an output shaft connected to said motor for delivering the plurality of torque impulses, a rotational movement detecting device, a torque transducer for generating a signal in response to each of the torque impulses delivered via said output shaft, and a control unit connected to said rotational movement detecting device and said torque transducer, said control unit including a device for setting a desired torque target value, a comparing circuit arranged to be activated by said rotational movement detecting device to compare said torque target value with a value of the delivered torque at the very instance said rotational movement detecting device indicates that a rotational movement of the screw joint ceases at each delivered torque impulse, and a motor power shut-off circuit connected to said comparing circuit and arranged to interrupt a power supply to said motor as the value of the delivered torque equals said torque target value.