| 摘要 |
PURPOSE:To prevent the generation of vibration and noise of a rod material and to enable execution of high speed rotation, by a method wherein by means of the rotary cylinder piston of the rear part of a lathe main spindle, the grip claw of a collet chuck in a cylinder hole is folded and unfolded simultaneously with the grip claw of the power chuck of the tip thereof. CONSTITUTION:When a lathe completes given machining, rotation of main spindle 3 is stopped, and a piston 23, to which pressure oil is fed through an oil passage 31a by means of a switching valve, is moved. A draw tube 24 is moved to the power chuck 4 side to unfold a grip claw 28. Simultaneously, an inner flange 26b of the piston 23 is brought into contact with a flange 17a, chucking sleeve 16 is moved, and a taper hole 16a, serving to press a collet 19, is separated to open a grip hole 19a. A rod material W is extruded by a given distance by means of a bar feeder device, pressure is fed through the oil passage 31b again, the piston 23 is moved leftward, and a grip claw 28 is folder to grip the portion near the tip of the rod material W. Simultaneously, the inner flange 26b and the flange part 17a are released from engagement with each other, the sleeve 16 is extruded through the force of a spring 18, the hole 16a presses the collect 19 to close the hole 19a, and the rod material W is gripped.
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