Abstract: A screwdriver includes a main part having a connection section, a reception section and an insertion section. A rotary unit is located in the reception section and has a base and a rotary member which has multipole holes and is rotatably located in the base. An end member is connected to the connection section and has a polygonal-hole section and a circular-hole section. A handle is mounted to the insertion section and has a push rod which extends through the main part, the rotary unit and the end member. The push rod has a magnetic connected to the distal end thereof The desired bit can be pushed to the end member by the push rod. The rotary member is replaceable for being cooperated with different types of bits.

Abstract: A calibration tool for a torque wrench includes a measuring head and a deflecting lever. On the deflecting lever are a signal processing unit, a communication unit and a calibration unit. The measuring head has a transducer configured to have a head portion of the torque wrench coupled thereto. The transducer generates measured signals during the calibration. The deflecting lever is provided for exerting a torque on the head portion of the torque wrench. The signal processing unit is electrically coupled to the transducer for processing the measured signals of the transducer. The communication unit associates with a data storage of the torque wrench for a data exchange therebetween. And the communication unit reads out the data storage of the torque wrench for obtaining a preset torque of the torque wrench for a release. The calibration unit calibrates the torque wrench by comparison of the torque exerted in the moment of the release to the preset torque at the torque wrench.

Abstract: A torque wrench includes a wrench body, a wrench head pivotally carried by the arm, a plunger, a pawl, a spring for urging the plunger, and an adjustment assembly. The adjustment assembly is operatively connected to the spring to vary an effective force of the spring on the plunger. The piezoelectric sensor is interposed in between the plunger and the spring for producing an output signal in response to the effective force exerted by the spring. A processor is provided for converting the output signal into an equivalent torque value, the equivalent torque value indicating a preset torque to be applied by the torque wrench to the workpiece. A display is further employed for displaying the equivalent torque value. Application of a torque greater than the preset torque to the workpiece causes the wrench head to pivot relative to the wrench body about a pivot joint.