Clamping mechanism for tool holder
AssigneeFanuc Corporation
InventorsAkihiko Fujimoto, Norio Watanabe, Masahiro Murota
Life of this patent
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Abstract
For a spring sliding on the drawbar, the coil spring is used; the removal work for keeping the inner diameters of the coil springs aligned is performed such that the clearance between the outer diameter of the drawbar and the inner diameter of the coil spring becomes a minimum; and the coil springs are caused to be guided integrally with the drawbar. By doing so, the movement of the center of gravity of the spring that is caused by repeated rotational operation of the main spindle or repeated tool clamping operation will be reduced and the amplitude by vibration will be made smaller.
Claims12
A clamping mechanism for a tool holder in which a drawbar is provided in a hollow part of a substantially hollow cylindrical spring so as to be able to advance and retract and coaxial with the spring, the tool holder is released by compressing the spring, and the tool holder is drawn into within a main spindle by a repulsion force of the spring, wherein
- said spring is a coil spring, the wire of which having a circular cross section;
- and
- said coil spring has been constructed such that a cylindrical removal work has been performed on the spiral inner wall of the coil spring in the spiral axial direction and that the inner diameter of the spring is larger than the outer diameter of the drawbar by a predetermined amount.
A clamping mechanism for a tool holder in which a drawbar is provided in a hollow part of a substantially hollow cylindrical spring so as to be able to advance and retract and coaxial with the spring, the tool holder is released by compressing the spring, and the tool holder is drawn into within a main spindle by a repulsion force generated when the compressed spring is going to restore to an original state, wherein
- said spring is a coil spring, the wire of which having a circular cross section;
- said coil spring has been constructed such that a cylindrical removal work has been performed on the spiral inner wall of the coil spring in the spiral axial direction;
- and
- said coil spring is such that in a compressed state, the inner diameter of the spring is larger than the outer diameter of the drawbar, and moreover, a difference between the inner diameter of the coil spring and the outer diameter of the drawbar is 0.1 mm or less.
A clamping mechanism for a tool holder in which a drawbar is provided in a hollow part of a substantially hollow cylindrical spring so as to be able to advance and retract and coaxial with the spring, the tool holder is released by compressing the spring, and the tool holder is drawn into within a main spindle by a repulsion force of the spring, comprising:
- pressing means for pressing said drawbar against the inner wall of the main spindle at a part in one radial direction;
- wherein said spring is a coil spring, the wire of which has a circular cross section;
- and
- said coil spring has been constructed such that a cylindrical removal work has been performed on the spiral inner wall of the coil spring in the spiral axial direction.
A clamping mechanism for a tool holder in which a drawbar is provided in a hollow part of a substantially hollow cylindrical spring so as to be able to advance and retract and coaxial with the spring, the tool holder is released by compressing the spring, and the tool holder is drawn into within a main spindle by a repulsion force of the spring, wherein
- said spring is a coil spring, the wire of which having a circular cross section;
- said coil spring has been constructed such that a cylindrical removal work has been performed on the spiral inner wall of the coil spring in the spiral axial direction and that the inner diameter of the spring is larger than the outer diameter of the drawbar by a predetermined amount;
- and
- there is provided pressing means for pressing said drawbar against the inner wall of the main spindle in one direction of the direction of the radius of the drawbar.
A method for forming a spring to be used in the clamping mechanism for a tool holder in which a drawbar is provided in a hollow part of a substantially hollow cylindrical spring so as to be able to advance and retract and coaxial with the spring, the tool holder is released by compressing the spring, and the tool holder is drawn into within a main spindle by a repulsion force of the spring, comprising the steps of:
- compressing the coil spring, the wire of which having a circular cross section, to a state in which the tool holder is held;
- and
- performing the removal work on the spiral inner wall of the coil spring in the compressed state in the spiral axial direction in a cylindrical shape, thereby making the inner diameter of the coil spring larger than the outer diameter of the drawbar and making the difference between the inner diameter of the coil spring and the outer diameter of the drawbar 0.1 mm or less.
Dependencies are inferred from the claim text.