| 摘要 |
A fastener driving arrangement in which there is a recess in the head of the fastener, having outwardly extending pockets with parallel sidewalls and bottom walls defined by spherical segments, the driver having blades adapted to fit in the recess pockets, the blades having end walls that are complementary to the inner recess wall and sidewalls which are adjacent the inner bottom corner of each recess pocket and diverge progressively away from the recess sidewall in both the radial and axial directions so that, when torque loads are applied, the recess wall will be caused to deflect to gradually increase the area of contact between the driver and recess.
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