DRIVE SYSTEM FOR THREADED FASTENERS

摘要

The invention provides a threaded fastener having a head (20) with a driving recess (22), the recess being of generally cruciform shape in cross-section transverse to the axis of the fastener to provide four driving segments (24) uniformly spaced around the axis of the fastener, each segment having a driven face extending axially for engagement by a corresponding driving face (8) of a driver (2) of complimentary form engageable within the recess, whereby when the driver of complimentary form is engaged within the recess (22) with driving ribs (4) of the driver located in the segments (24), the ribs of the driver will be wedged between the peripheral surfaces (26) of the diametrically opposed segments and the opposed driven and trailing faces (28, 30) of each segment. The design of the recess avoids "cam out" and wobbling of the driver. The invention also provides a driver of complimentary form to that of the recess.