| 摘要 |
PROBLEM TO BE SOLVED: To provide a power screwdriver holding structure for preventing a male screw from being bitten into a tap during starting tightening the screw and preventing a bit of the power screwdriver from being removed from a cross hole of the male screw during completing tightening the screw. SOLUTION: Linear guides 7a, 7b are guided by linear shafts 4a, 4b and fixed to a power screw driver body 50 via an elevation plate 1, a collar 20, and bolts 21a, 21b. Springs 5a, 5b are subjected to the dead weight WO of the screwdriver and shrunk to the minimum length. When a bit 51 is put on a cross hole of a male screw, small thrust P1 which is obtained by subtracting the repulsive force F1 of the springs 5a, 5b from the dead weight WO is applied to the male screw to prevent the male screw from being bitten into a tap during starting tightening the screw. When fixed plates 2, 3 are moved down, springs 6a, 6b are shrink and great thrust P3 which is obtained by adding the repulsive force F2 of the springs 6a, 6b to the dead weight WO is applied to the male screw to prevent the bit 1 from being removed from the cross hole even if the male screw is tightened with great torque.
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