| 摘要 |
PURPOSE: To obtain a line-spacing device having half-step feed by making the snap stopping force of a gripper point smaller than the resistance force reversely directed to the driving by the grip leading end during the feed phase of a gear having a platen in a tangential direction and allowing the interval between both snap stopping end part positions to correspond to the feed process of a half feed step. CONSTITUTION: When a gripper point 20 is engaged with a gear 4 so that tensile motion, for example, the feed motion in the direction shown by an arrow 31 is performed, the resistance force of the gear acts by the tensile motion and advance motion acts outwardly. This force is absorbed perfectly and, when the rotary direction of a line-spacing motor 12 is kept, advance line-spacing having all pitches is performed. If the rotation is reversed, the gripper point 20 is engaged with the gear 4 through a motion phase III and the pressing action opposite to the arrow 31 is performed. When the motion resistance of the gear 4 again acts on the gripper point 20 now, a snap stopping projection 30 is positioned to a groove 27 from a groove 28. Both grooves have a distance corresponding to the half of the pitch (t) of the gear 4 and feed sliding motion by a half pitch is performed.
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