| 摘要 |
PURPOSE:To improve the reproducibility of head feeding accuracy with a head positioning device composed of a lead screw shaft and a plate spring which forces a needle shaft, by providing solid-state slipping members between the plate spring and/or needle shaft and lead screw shaft. CONSTITUTION:Solid-state slipping members 11 and 11 are provided between a lead screw shaft 8 and needle shaft 9 and between the lead screw shaft 8 and a plate spring 10 and the slipping efficiency between the through section of the lead screw shaft 8 and needle shaft 9 and the contacting surfaces of the outer peripheral surface of the lead screw shaft 8 and plate spring 10 is extremely improved. Therefore, the difference in the feeding direction of a head, namely, so called hysteresis is set at about 4mum and, as a result, the accuracy is improved.
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