Patent Application
20080224425
The present invention relates to a tool chucking apparatus and particularly to a chucking apparatus to hold cutters or tools of varying specifications.
These days precision metal machining such as drilling, tapping, boring, milling, cutting of inner or outer diameters or surface grinding usually relies on CNC (Computer Numerical Control) machine tools in cooperation with a plurality of cutters or tools. Those cutters or tools mostly have an elongated stem connecting to a driving spindle of the CNC machine tools through a chucking apparatus or chucking structure. The driving spindle rotates in high speed to drive the cutters or tools held by the chucking apparatus to perform machining on a targeted object. Hence the holding condition of the chucking apparatus on the cutters or tools directly affects the machining precision of the targeted object. If clamping is not tight enough during high speed rotation of the machining tool idle rotation of the cutters or tools occurs. Referring to
The clipping member 2 equipped with the pawl structures 5 to hold the cutter or tool has many advantages, such as can hold cutters or tools of varying sizes and specifications. Moreover, when the holding member 3 and the fastening member 1 are screwed together, they automatically clamp the cutter or tool in an optimal condition. However, the pawl structures 5 can hold only a small portion of cutters or tools. In the event that the cutter or tool is shorter, the pawl structures 5 can provide enough clamping power to keep the cutter or tool from skewing during high: speed rotation in the machining process. However, if the cutter or tool is lengthy and the pawl structures 5 can clamp only a distal end thereof, a great portion of the cutter or tool is exposed outside the chucking apparatus. As the targeted object to receive machining usually is a hard article such as metal, and the driving spindle (not shown in the drawing) of the machining tool rotates at the high speed, with a great force applied to the cutter or tool, or the forcing angle being not vertical, the cutter or tool could be skewed. As a result machining precision suffers. It could even cause damage of the tool chucking apparatus or the machining tool and result in a great loss of cost.
The primary object of the present invention is to provide a tool chucking apparatus to enhance holding firmness of a cutter or tool on a machining tool during machining for a targeted metal to prevent suffering of precision and damage of the machining cutter or tool. To achieve the foregoing object the tool chucking apparatus of the invention includes a fastening member, a clipping member, a holding member and an extension member. The fastening member has a first housing space inside to hold the clipping member. The clipping member has a plurality of pawl structures which are spaced in an annular manner and formed in a conical structure. The pawl structures have a top end directing towards the fastening member. The extension member is located between the holding member and the fastening member, and includes a support portion and an anchor portion that are coupled together. The support portion and the fastening member are coupled through a first coupling portion. The support portion and the anchor portion are coupled respectively with the holding member through a second coupling portion and a third coupling portion. In addition, the fastening member has an annular fastening element. The clipping member has an annular groove corresponding to the annular fastening element that can be engaged to form a firm coupling between the clipping member and the fastening member such that the distal end of the clipping member has a sufficient clamping power. The first coupling portion and the second coupling portion are coupled at a juncture which has at least one through threaded passage formed thereon to receive at least one corresponding bolt to strengthen the coupling of the fastening member and the extension member. The fastening member, clipping member, holding member and extension member are hollow in the center and form an installation passage after assembly to hold a cutter or tool. Moreover, varying lengths and specifications of the support portion of the extension member may be selected according to the cutter or tool to be used.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
Please refer to
The inserting cutter or tool is deeply held in the installation passage 13. It has a portion exposed outside the tool chucking apparatus that can be adjusted and anchored through the clipping member 20. The clipping member 20 is the main structure to hold the cutter or tool. The conical structure formed by the pawl structures 21 makes the clipping member 20 elastic. When the cutter or tool of varying specifications is inserted the pawl structures 21 can adjust the internal diameter thereof. After the clipping member 20 has been held in the holding member 40, and the fastening member 10 and the holding member 40 are coupled together, the pawl structures 21 are shrunk naturally inwards to clamp the cutter or tool to prevent the cutter or tool from loosening during machining at high rotation speed. The conical structure of the clipping member 20 has a top end directing towards the fastening member 10 to clamp the front end portion of the cutter or tool. While the front end of the cutter or tool is clamped tightly by the clipping member 20, only a small portion is exposed outside. Thus the impact of external forces decreases. As a result, the machining precision of the cutter or tool on the targeted object increases significantly. Moreover, to increase the clamping force of the bottom end of the clipping member 20 over the inserting cutter or tool, the fastening member 10 has an annular fastening element 14 while the clipping member 20 has a corresponding annular groove 22 to be wedged by the annular fastening element 14 to form a firm coupling between the clipping member 20 and the fastening member 10.
As the machining cutter or tool is not limited to one specification, aside from different sizes, the length could also be different. Although the holding position of the cutter or tool inserted into the installation passage 13 may be adjusted, to provide required firmness by the tool chucking apparatus for a special length specification of cutter or tool could be difficult. This could result in machining deviations.
In response to the cutter or tool of varying length specifications, the support portion 31 may be replaced as desired. Such a design greatly improves applicability and convenience of the tool chucking apparatus. Moreover, the invention provides more strengthening designs that can enhance the firmness of the cutter or tool during machining at high speed rotation, and improve machining precision.
While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other, embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.
