Patent ID: 8888420

Claim:
A tool chucking apparatus for holding a machining cutter or tool, comprising: a holding member and a fastening member that have corresponding coupling structures to form the chucking apparatus, the holding member and the fastening member being coupled to form a grip space, the holding member having a first contact surface in the grip space, the fastening member having a second contact surface, the first contact surface and the second contact surface having respectively a grip angle, wherein the fastening member has an encasing portion, the holding member and the encasing portion having respectively a fifth contact surface and a sixth contract surface corresponding to and forming a closed contact with each other, and wherein the first contact surface has an edge formed on top of the holding member, and the second contact surface has an edge formed in the grip space and corresponds to the edge of the first contact surface; and a collet which is held tightly in the grip space and has a plurality of pawl structures, the pawl structures having a plurality of elastic slots spaced from each other and a third contact surface at one end corresponding to the first contact surface and a fourth contact surface at the other end corresponding to the second contact surface, wherein an annular slot is formed between the third contact surface and the fourth contact surface, and two corresponding edges of the first contact surface and the second contact surface are located directly radially outward of the annular slot, such that the two corresponding edges are within an axial extent of the annular slot; wherein when the holding member and the fastening member are coupled, the third contact surface butts the first contact surface and the fourth contact surface butts the second contact surface, and the collet is moved to shrink the elastic slots so that the first contact surface and the third contact surface are contacted closely and the second contact surface and the fourth contact surface are contacted closely such that the collet and the holding member and the fastening member form a compact coupling and two ends of the collet tightly grip the cutter or tool held in the tool chucking apparatus.