Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
440 words
A self holding screw comprising an elongated threaded screw shank having a conical side wall, a leading end for entry into a work piece and a trailing engagement end for driving engagement with a screw driving tool, an elongated cavity in said screw shank opening to said trailing engagement end and closed at its opposite end, a retaining member positioned in said cavity for reciprocal movement therein toward said leading end and toward said trailing end, said retaining member including a solid elongated body portion, the cross-sectional configuration of said solid elongated body portion corresponding to the cross-sectional configuration of said elongated cavity, a plurality of integrally formed projecting fingers on said retaining member extending diagonally from said retaining member at an acute angle facing toward said trailing end, aperture means through said conical side wall of said screw shank opening to said elongated cavity in registration with said fingers of said retaining member seated in said elongated cavity for reception of said fingers through said aperture means and movement of said fingers relative to said aperture means wherein said fingers project outwardly beyond the said conical side wall of said screw shank in an extended position and wherein said fingers are withdrawn completely within the circumferential surface and boundary of said screw shank in a retracted position, and reciprocating means to move said retaining member and fingers between said extended and retracted positions, wherein said elongated cavity in said screw shank includes a circular internally threaded portion extending inwardly from said trailing engagement end for a short distance, an externally threaded set screw of short longitudinal dimension to threadedly engage with said internally threaded portion of said cavity and to seat therein, said reciprocating means including a compression spring seated at the opposite end of said elongated cavity, said spring being movable longitudinally between a compressed and a released position, said compression spring requiring mechanical advantage means to compress and having sufficient force when released to move longitudinally toward said released position to force said retaining member toward said trailing engagement end and said fingers outwardly of said aperture means to said extended position thereof for penetration into said work piece, said retaining member extending from abutment against the inner surface of said set screw at one end to abutment against said compression spring at the opposite end, said compression spring being moved to its compressed position by said retaining member when said set screw has been fully seated at the opposite end, said mechanical advantage means including said externally threaded set screw threadedly engaged with said internally threaded portion of said cavity at said trailing engagement end thereof.
Claim 2
Dependent Claim
440 words
A self holding screw comprising an elongated threaded screw shank having a conical side wall, a leading end for entry into a work piece and a trailing engagement end for driving engagement with a screw driving tool, an elongated cavity in said screw shank opening to said trailing engagement end and closed at its opposite end, a retaining member positioned in said cavity for reciprocal movement therein toward said leading end and toward said trailing end, said retaining member including a solid elongated body portion, the cross-sectional configuration of said solid elongated body portion corresponding to the cross-sectional configuration of said elongated cavity, a plurality of integrally formed projecting fingers on said retaining member extending diagonally from said retaining member at an acute angle facing toward said trailing end, aperture means through said conical side wall of said screw shank opening to said elongated cavity in registration with said fingers of said retaining member seated in said elongated cavity for reception of said fingers through said aperture means and movement of said fingers relative to said aperture means wherein said fingers project outwardly beyond the said conical side wall of said screw shank in an extended position and wherein said fingers are withdrawn completely within the circumferential surface and boundary of said screw shank in a retracted position, and reciprocating means to move said retaining member and fingers between said extended and retracted positions, wherein said elongated cavity in said screw shank includes a circular internally threaded portion extending inwardly from said trailing engagement end for a short distance, an externally threaded set screw of short longitudinal dimension to threadedly engage with said internally threaded portion of said cavity and to seat therein, said reciprocating means including a compression spring seated at the opposite end of said elongated cavity, said spring being movable longitudinally between a compressed and a released position, said compression spring requiring mechanical advantage means to compress and having sufficient force when released to move longitudinally toward said released position to force said retaining member toward said trailing engagement end and said fingers outwardly of said aperture means to said extended position thereof for penetration into said work piece, said retaining member extending from abutment against the inner surface of said set screw at one end to abutment against said compression spring at the opposite end, said compression spring being moved to its compressed position by said retaining member when said set screw has been fully seated at the opposite end, said mechanical advantage means including said externally threaded set screw threadedly engaged with said internally threaded portion of said cavity at said trailing engagement end thereof.