| 摘要 |
PURPOSE:To fulfill the function of centering and locking and improve positioning accuracy in a machining position by forming the piston part of a quill inserted in the cylinder chamber of a head and the front and rear ends of a collet type piston, into conical tapers and making each tapered part opposed to another part respectively, CONSTITUTION:When a quill 3 is in an advanced condition, a liquid 31 is led to a passage 29, a piston 4 and a piston part 9 are moved in the advancing direction under pressure, a tapered surfce 11 is brought in contact by pressure with a tapered surface 12 while a tapered surface 13 also being brought in contact by pressure with a tapered surface 14 at the rear. Thereby, indexing into centering position is made automatically, and the axis of the quill 3, i.e., the axis of a spindle 5 and a tool 32 fitted to a tool mounting hole 17, can be positioned with high accuracy, permitting high reproducibility and, therefore, highly accurate positioning can be ensured for a long time. On the other hand, when the piston 4 pushes the piston part 9 of the quill 3 in the advancing direction, since the claws of a collet 15 are deformed so as to spread its diameter against the inner periphery of a cylinder chamber 8, the frictionally stopping force between the collet claws and the inner periphery of the head 2 provides a locking condition. |
