Abstract: A power wrench includes a housing inside which an electric motor is mounted. A torque/rotation transmission mechanism is also disposed inside the housing to be coupled to the motor to drive a driving tip thereof extending out of a front end of the housing for engagement with a bolt/nut to be loosened or tightened. The transmission mechanism includes a cylindrical main body with a cylindrical projection concentrically integral therewith to connected to the spindle of the motor so as to transmit rotation to the main body. A coupling member is pivotally mounted on the main body and controlled by a centrifugal clutch to intermittently hit an output shaft along a circumferential direction to apply a torque impulse to the output shaft for loosening or tightening the bolt or nut. A lamp is provided on the front end of the housing to project a light beam to the bolt or nut to allow the operator to monitor the operation of the power wrench in a dark environment.

Abstract: A power screwdriver disclosed includes a housing, a reversible motor, a screw-driving device, a transmitting shaft, and a handle. The screw-driving device includes a centrifugal clutch, a rotor and an engaging set. The shaft is connected to the motor at one end and to the rotor at the other end so as to transmit rotating power from the motor to the rotor. The screwdriver automatically switch screwing actions in accordance with the rotating speed thereof.

Abstract: A mechanical jack comprising a base, on which a fixed frame is fixed. The fixed frame is substantially up-standing, slightly inclining toward one side with a supporting frame attached thereon to maintain the fixed frame in its inclined position. A moveable frame with one end thereof pivotally attached on the fixed frame is rotatable with respect to the fixed frame about the pivot. A threaded rod, which has a threaded portion engaging with an inner-threaded block pivotally mounted on the other end of the moveable frame by means of a replaceable bearing element and a smooth portion running through and secured on a pivot mounted on the fixed frame, retracts and extends, when rotated about the central axis thereof, the moveable frame with respect to the fixed frame so that heighten and lower a vehicle support attached on the moveable frame.

Abstract: A mechanical jack comprising a base with wheels attached thereon for moving the jack, a primary arm of which an end is pivoted on the base so as to be rotatable with respect to the base, a secondary arm of which an end is pivotally mounted approximately on the middle of the primary arm so as to be rotatable with respect to the primary arm, and a threaded rod threadingly connecting between the free ends of the primary and secondary arms so that when the threaded rod is rotated, the free ends of the primary and secondary arms move towards or away from each other, depending upon the rotation direction of the threaded rod. With the pivoted ends as the rotation centers, moving the free ends of the arms will also heighten the free end of the secondary arm so as to lift a vehicle supported thereon.