Abstract: A method of controlling driving power of a double-solenoid electric percussion tool utilizing the change of energizing time of the first solenoid to control the location of a hammer when the first solenoid is switched to the second solenoid so as to increase the driving power of a percussion tool.

Abstract: A flash light is provided in which the rotary positioning mechanism that retains the lamp head holder to the hollow cylindrical handle at any of a variety of angular positions includes a curved stub tube extending from the sloping bottom wall of the lamp head holder. The stub tube has an internally threaded, straight top end and a straight bottom end. The bottom end extends from the top end at an angle and perpendicularly intersects the sloping bottom wall of the lamp head holder. A plurality of circular recesses are formed in the sloping top wall of the hollow cylindrical handle and radially spaced around the center of the sloping top wall. A spring is mounted within the top end of the curved stub tube. A first steel ball is mounted in the bottom end of the curved stub tube, and a second steel ball is mounted within the top end of the curved stub tube and disposed between the first steel ball and the spring.

Abstract: A flashlight including an elongated housing having a spherical seat at an upper end thereof and containing a battery, the spherical seat being formed with a plurality of grooves on an inner side thereof, a head assembly pivotally mounted in the spherical seat and including a rotatable head carrying a light bulb, the head being provided with a resilient member at a bottom thereof adapted to engage with the grooves, and means for switching the flashlight on and off, whereby the flashlight can be set to keep illuminating a particular place as desired.