| 摘要 |
A screw ( 10 ) has a threaded shank ( 12 ) and a head ( 14 ). The head has a recess ( 18 ) that comprises three lobes ( 18 a,b,c). Each lobe is separated by a curved drive flange ( 20 a,b,c,). A driver ( 100 ) has a drive tip ( 114 ) that fits the recess of the screw.
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