CPC B25B 23/108 (2013.01) [B25B 15/004 (2013.01); B25B 15/008 (2013.01); F16B 23/003 (2013.01); F16B 23/0007 (2013.01); F16B 23/0038 (2013.01)] | 5 Claims |
1. A fastener having a head portion with a recessed socket area extending into the head portion and a shank sharing a longitudinal axis with the recessed socket area, comprising:
a sidewall defining the recessed socket area having a top edge and a bottom edge; and
a plurality of driving surfaces and removal surfaces disposed along the sidewall, wherein:
an upper section of the sidewall tapers inwardly towards the longitudinal axis between about one degree and about three and three-fifths degrees from the top edge to a curvilinear transition line; and
a lower section of the sidewall forms a vertical surface parallel to the longitudinal axis and is disposed between the curvilinear transition line and the bottom edge, wherein:
the lower section of the sidewall is offset in the clockwise direction from the upper section of the sidewall by a rotation of between one degree and six degrees causing the curvilinear transition line to vary along a length of the plurality of driving surfaces and removal surfaces between the top edge and the bottom edge; and
a driving surface of the lower section of the sidewall at the bottom edge is aligned with a driving surface of the upper section of the sidewall to form a vertical line of insertion extending from the top edge to the bottom edge.
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