Abstract: An actuating device for an electrical power wrench includes a base member connected to a motor and an output shaft is rotatably connected to the base member. A pin biased by a spring movably extends through the base member. A ball biased by a spring is received in the base member and engaged with a groove defined in an outside of the pin. A movable frame with a weight movably retained between two blocks on the base member and two springs connected between the two ends of the movable frame and the two blocks. An L-shaped actuating member is rotatably connected between the two blocks and pivotably connected to two lugs of the movable frame. When the base member is rotated by the motor, the movable frame radially moves due to the eccentric force to pivot the actuating member. When the force being put on to the pin by the actuating member overcomes the froce of the two springs, the pin extends to impact a plate extending radially outward from the output shaft to output a sudden and large torque.

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.