Self-retained bolt assembly

Claim 2

A self-retained bolt assembly including a bolt shank having a free threaded end portion, a circumferentially compressible ring of a synthetic resinous material carried in an annular groove in said shank at or adjacent the last thread on said end portion and a nut member having an axial bore including a first threaded section adapted to be threadably engaged with said threaded end portion and a second unthreaded section having a larger diameter than said first section, said nut member further including a castellated annular section defining a portion of said first threaded section and said threaded end of said shank including a transverse bore adapted to receive a cotter pin whereby said pin and castellated section of the nut cooperate to prevent rotation of the nut, said ring having a larger outside diameter than the diameter of said second unthReaded section and said second unthreaded section being adapted to surround and circumferentially compress said ring when said nut member is threaded on said threaded end portion of said bolt, whereby a frictional engagement is created between said nut and the ring which is operative to resist rotation of said nut.

Claim 3

A self-retained bolt assembly as defined in claim 1, wherein said ring is deformed by said second unthreaded section to substantially conform to the contours of said second unthreaded section and a portion of said ring is constrained between said second unthreaded section, the unthreaded portion of said shank and said groove to provide an enlarged frictional contact area between said ring and said nut whereby resistance to nut rotation is increased.

Claim 4

The self-retained bolt assembly as defined in claim 1 wherein said ring is made from a polyamide.

Claim 5

The self-retained bolt assembly as defined in claim 1 wherein said ring is made from a plastic selected from the group consisting of polyethylene, polypropylene and Teflon.

Claim 6

A joint comprising: a plurality of workpieces having aligned apertures passing through said workpieces, a self-retained bolt installed in said aligned apertures including a bolt having a threaded shank and an enlarged head and a circumferentially compressible ring of a synthetic resinous material carried by said bolt in an annular groove positioned at or adjacent the thread runout, the bore diameter of the uncompressed ring being larger than the groove diameter but smaller than the major thread diameter, the maximum external diameter of the uncompressed ring being greater than the diameter of said aperture in said workpiece closest to said ring, the maximum external diameter of the circumferentially compressed ring is no greater than said diameter of said aperture in said workpiece closest to said ring, said ring having a slot throughout the axial extent thereof of sufficient width to provide for the circumferential compressibility, said bolt positioned so that the full shank length is in bearing and said ring is outside said aperture in said workpiece closest to said ring, a nut turned on to said self-retained bolt and holding said self-retained bolt in clamping engagement and said nut being counterbored at its bearing face to a diameter less than the maximum external diameter of said uncompressed ring.

Claim 7

A joint comprising: a plurality of workpieces having aligned apertures passing through said workpieces, a self-retained bolt installed in said aligned apertures including a bolt having a threaded shank and an enlarged head and a circumferentially compressible ring of a synthetic resinous material carried by said bolt in an annular groove positioned at or adjacent the thread runout, the bore diameter of the uncompressed ring being larger than the groove diameter but smaller than the major thread diameter, the maximum external diameter of the uncompressed ring being greater than the diameter of said aperture in said workpiece closest to said ring, the maximum external diameter of the circumferentially compressed ring is no greater than said diameter of said aperture in said workpiece closest to said ring, said ring having a slot throughout the axial extent thereof of sufficient width to provide for the circumferential compressibility, said bolt positioned so that the full shank length is in bearing and said ring is outside said aperture in said workpiece closest to said ring, a nut turned on to said self-retained bolt and holding said self-retained bolt in clamping engagement and said nut being counterbored at its bearing face to a diameter less than the maximum external diameter of said uncompressed ring.

Claim 8

A joint as defined in claim 5 wherein said nut has a castellated annular section, said bolt has a transverse bore extending through its threaded end, and a cotter pin extends through said transverse bore and said castellated annular section.