Abstract: A combination type electric drill chuck structure is mainly mounted on an electric drill. The chuck includes a drive body having head and tail ends, the middle thereof being provided with multiple inclined grooves for receiving multiple clamp pawls; a fixed shell secured fittingly at the tail end of the drive body; a sleeve threaded seat threadedly provided at head end of the drive body for engagement with the clamp pawls; a percussion ring provided with a spring for engaging the sleeve threaded seat in normal condition; a movable shell that utilizes an adjusting ring to adjust upper and lower positions. When the user turns the adjusting ring, the position of the movable shell can be adjusted to engage or disengage the sleeve threaded seat or fixed shell so as to achieve various operating modes of automatic percussion locking, manual locking and locking positioning of the drill bit.

Abstract: A chuck structure with locking and positioning functions includes a cylindrical body having head and tail ends, the middle thereof being provided with a plurality of inclined channels; a plurality of clamp pawls received in the channels; a limiting ring provided at the middle of the cylindrical body and having a plurality of equidistantly spaced apart through slots annularly provided at the center thereof for passage of the clamp pawls; a drive seat rotatably mounted at the head end of the body for enclosing and engaging the clamp pawls; and an outer shell for enclosing the drive seat. The outer shell includes upper and lower shell bodies. In use, the user turns the upper shell body to cause the clamp pawls to retract inwardly to clamp a tool, with the outer shell and the limiting ring providing a positioning effect so that the clamp pawls will not slip due to vibration or excessive torque, and the tightening force can be maintained.

Abstract: A self locking device for a power tool includes a cylindrical member for receiving a tool member, three or more pawls slidably engaged into the cylindrical member to engage with the tool member and each having a threaded surface, a barrel threaded with the threaded surfaces of the pawls and having one or more teeth extended from one end. A ferrule is rotatably engaged on the barrel and may be forced toward the barrel to hold the barrel in place for allowing the pawls to be rotated relative to the barrel to engage with the tool member when the barrel is secured to the ferrule.