Fastener recess
OwnerHilary H. Cunninghaminventor
Life of this patent
Estimating the term…
Abstract
A recess for fasteners such as screws, bolts and the like having, in axial alignment with the shank, a central recess of a conic-frustum shape which serves as a natural center for a driver tool or for a drill bit if it becomes necessary to drill out the fastener. The wrenching elements consist of a plurality of truncated conic segments having their common center line axis coincident with the central recess. The wrenching walls for loosening lying in a plane containing the center line axis of the fastener while the walls for tightening being sloped toward the tightening direction to provide for torque limiting.
Claims7
A rotational fastener having a recess and associated driver tool comprising;
- (a) centrally disposed frusto-conical recess carrier by the fastener surrounding the rotational axis thereof, a plurality of equally spaced wrenching element recesses extending radially outwardly from the frusto-conical recess, each wrenching element recess comprising a first force application face lying in a plane containing the fastener rotational axis and an oppositely disposed second force application face, means carried by the second face to limit the force that can be applied thereto;
- and
- (b) the driver tool comprising a shank, driver head at one end of the shank, said driver head having a convex shape to conform to the fastener recess.
A rotational fastener having a recess comprising:
- (a) a centrally disposed recess surrounding a rotational axis of the fastener;
- and
- (b) a plurality of equally spaced wrenching element recesses extending radially outwardly from the recess, each said wrenching element recess comprising a removal face lying in a plane containing the rotational axis of the fastener and an oppositely disposed installation face substantially radially extending and lying in a plane which intersects said fastener rotational axis, the outer portion of said installation face being tilted in a direction away from the removal face.
A rotational fastener having a recess in a head portion thereof comprising:
- (a) a centrally disposed recess surrounding a rotational axis of the fastener, said recess having frusto-conical walls extending from an outer face of the fastener head and terminating at a base of the recess with a centrally disposed indent;
- and
- (b) a plurality of equally spaced wrenching element recesses extending radially outwardly from the frusto-conical walls of the recess, each said wrenching element recess extending from the base of said frusto-conical wall outwardly to the outer face of the fastener head, each said wrenching element recess comprising a removal face lying in a plane containing a rotational axis of the fastener and an oppositely disposed installation face substantially radially extending and lying in a plane which intersects said fastener rotational axis, the outer portion of said installation face being tilted in a direction away from the removal face.
Dependencies are inferred from the claim text.