Abstract: A three-speed gear shifting box for power-driven tools includes a triple gear fitted on an output shaft of an electric motor, and planetary gears are sleeved respectively on three planetary gear shafts of an intermediate gear disk and are meshed respectively with the triple gear and internal gears. A poking spring makes an internal gear regulating ring move and fix one of the internal gears. Gears on the intermediate gear disk mesh with planetary gears on four planetary gear shafts, on the main shaft, and the planetary gears also mesh with the fixed internal gear.

Abstract: An AC, DC interchangeable multipurpose combination power tool, characterizes in that a main body of AC power tool and a main body of DC power tool are combined with a variety of tool heads in interchangeable way. The combination is accomplished via an outer spline arranged on the main body and an inner spline arranged on the tool head. The main body is provided with locking mechanism to tightly lock up the tool head. The combination power tool can be widely applied at working sites whether power supply network is available or not, and can satisfy different working requirements.

Abstract: A multipurpose combination tool comprises a main body portion with a motor and drive shaft, and an interchangeable tool head portion that can be removably coupled to the main body portion through a locking mechanism and power transmission device for transmitting power from the main body portion to the tool head portion. The locking mechanism includes a thrust ring, a locking ring and a locking pad operably associated with the main body portion and a locking head operably associated with the tool head portion. The power transmission device comprises an internal spline on the main body portion that meshes with an external spline on the tool head portion. In this manner, the tool head portion associated with one task, such as drilling, can be changed for other tool head functions associated with other tasks, such as sanding, grinding, mixing, sawing, and so on to thereby provide multiple tasking with one machine.

Abstract: A charging type multipurpose combination tool comprises a main body portion releasably connectable to a plurality of interchangeable tool head portions through a locking mechanism. The main body portion includes an electric motor, a speed control switch and a battery set, while the interchangeably tool head portion may be arranged to form an electric drill, a sanding machine, an angular grinding machine, a cement mixer, a sawing machine, an engraving machine, and the like. The locking mechanism includes an external spline fixed on the electric motor output shaft for rotation therewith and an internal spline located on the locking head that meshes with the external spline for transmitting power to the tool head portion. A locking piece on the main body portion has wedged-shaped faces that releasably engage a locking head on the tool head portion.

Abstract: A three-speed gear shifting box for power-driven tools, characterized in that on a triple gear is fitted on output shaft of electric motor, and planetary gears are sleeved respectively on three planetary gear shafts of an intermediate gear disk and are meshed respectively with the triple gear and internal gears. A poking spring makes an internal gear regulating ring move and fix one of the internal gears. Gears on the intermediate gear disk mesh with planetary gears on four planetary gear shafts on the main shaft, and the planetary gears also mesh with the fixed internal gear.