| 摘要 |
A novel drive bit for mounting in a sleeve of a rotary driving tool for driving a slotted screw having a hollow cap with a threaded interior cylindrical wall having an inner minor diameter comprises a driver portion at one end thereof and a sleeve engaging portion at the other end thereof, wherein the driver portion includes a generally cylindrical aligning portion with a predetermined diameter of between about 85% and about 99½% of the inner minor diameter and a pair of laterally opposed concave surfaces tapering at a predetermined radius of curvature of between about 50% and about 150% of the inner minor diameter to a generally rectangular flat headed tip for engaging the slot of the screw while the generally cylindrical aligning portion aligns the cap and the screw substantially coaxially with the bit.
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