Abstract: A power tool has a driving shaft for driving a working element and a clamping device for clamping the working element. The clamping device has a clamping position in which the working element may be fixed relative to the driving shaft and a release position in which the working element can be removed from the driving shaft. An operating member is coupled to the clamping device for moving the clamping device between positions. The clamping device also has a rotating position in which the working element can be rotated by an angle relative to the driving shaft and the operating member has an operating position that corresponds to the rotating position.

Abstract: A condenser lens suitable for a laser rangefinder includes a lens body wherein the lens body is formed with or has attached thereto a deviation correction area that is located on the light emitting side thereof for correcting focus deviation upon reception of light scattered by a close range object. A center of the body is located inside the deviation correction area of the lens. The deviation correction area may include one or more deviation correction zones.

Abstract: A chain saw includes a housing, an oil supply system disposed in the housing, a trigger linkage assembly, and a switch controlled by the trigger linkage assembly. The oil supply system includes an oil can and an oil pump assembly connected with the oil can via an oil inlet tube. The trigger linkage assembly includes a switch trigger. The chain saw further includes a pressing member driven by the trigger linkage assembly. When the switch trigger is not activated, the pressing member is located at a first position and can press the oil inlet tube tightly to isolate an oil circuit of the oil supply system. When the switch trigger is pressed down, the pressing member can be driven by the trigger linkage assembly to a second position to release the pressing for the oil inlet tube so that the oil circuit of the oil supply system is allowed to flow.