| 摘要 |
PROBLEM TO BE SOLVED: To always smoothly perform a rotating work, even at a bending angle of≥30°, for improving a box wrench. SOLUTION: One recessed groove part 2 and the other recessed groove part 4 having a recessed arc surface 3 formed at a deep wall are provided in one part and the other part of a box member 1, respectively. A small recessed groove 7 is provided in a center part outside a chamfering projecting part 6 of a joint 5 fitted to the other recessed groove part 4. An extension spring 8 is fitted and inserted into the small recessed groove 7 and a ball 9 is arranged at the outer end part. The ball 9 is brought into pressure contact with the recessed arc surface 3 of the deep wall of the other recessed groove part 4 of the box member 1. A joint 13 is mounted and supported between the one recessed groove part 2 of the box member 1 and one recessed groove part 12 of a lever member 11. One chamfering projecting part 14 and the other chamfering projecting part 15 of the joint 13 are arranged in the one recessed groove part 2 of the box member 1 and the one recessed groove part of the lever member 11, respectively. A middle groove part 19 provided in the lever member 11 includes an extension spring 20 having one end part brought into pressure contact with a bottom of the middle groove part 19 and the other end part fixed to the chamfering projecting parts of the joint 13. COPYRIGHT: (C)2011,JPO&INPIT
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