Fixed force level bolt

Claim 2

A bolt of ductile material which comprises: a. a first part which includes a bolt head integrally secured to said bolt, the bolt head having an outer wrenching surface, and includes a ring-like extension depending therefrom adjacent to said outer wrenching surface and defining an axially extending internally directed surface; b. a second separate part having an outer wrenching surface, with one end thereof engaging said internally directed surface and abuttingly secured to the extension of said bolt head and extending along said bolt, the other end thereof terminating in a bearing surface; c. said second part having an inner surface spaced apart from the outer surface of the bolt to define therewith a radial clearance; and d. an external radially directed annular groove defined by said outer wrenching surfaces, the external groove being less in axial width than twice the radial thickness between the bottom of the external groove and the inner surface thereby defining an annular section which plastically deforms radially inward with an essentially wedge-shaped cross section when a predetermined force acts on the bolt with resultant reduction of the axial width of the external groove.

Claim 3

The bolt of claim 1 wherein the second part has a sleeve extending therefrom, said sleeve received in mating relationship by the ring-like extension of the bolt head.

Claim 4

The bolt of claim 2 wherein the annular section which plastically deforms radially inward is disposed entirely within the sleeve of the second part.

Claim 5

The bolt of claim 1 wherein the wrenching surfaces of the first and second parts are of equal diameter.

Claim 6

The bolt of claim 1 wherein the other end of the second part terminates in a conical bearing face such that the outer edge of the face first contacts the abutting surface and of an angle at least equal to the rotation of said face when said predetermined bolt force acts on the bolt whereby a uniform bearing stress acts between said lower bearing face and said abutting surface.

Claim 7

The bolt of claim 4 wherein a flowable imcompressible material is disposed within said groove.

Claim 8

The bolt of claim 6 wherein the material is electrically conducting.

Claim 9

A bolt of ductile material which comprises: a first part including a bolt head integrally secured thereto, said bolt head having an outer wrenching surface, a cylindrical extension depending from said bolt head and having an inner surface spaced apart from the outer surface of the bolt; a second part comprising a force ring having an outer peripheral wrenching surface of substantially the saMe diameter as the bolt head and a sleeve extending therefrom, said sleeve having an inner and an outer surface, the outer surface of the sleeve engaging in abutting relationship the inner surface of the cylindrical extension, the inner surface of the sleeve spaced apart from the outer surface of the bolt to define a radial clearance therewith; an external radially directed annular groove formed on said outer wrenching surface by the bolt head and the force ring, the external groove being less in axial width than twice the radial thickness between the bottom of the external groove and the inner surface of the sleeve thereby defining an annular section which plastically deforms radially inward with an essentially wedge-shaped cross section when a predetermined force acts on the bolt with resultant reduction of the axial width of the external groove.

Claim 10

A bolt of ductile material which comprises: a first part including a bolt head integrally secured thereto, said bolt head having an outer wrenching surface, a cylindrical extension depending from said bolt head and having an inner surface spaced apart from the outer surface of the bolt; a second part comprising a force ring having an outer peripheral wrenching surface of substantially the saMe diameter as the bolt head and a sleeve extending therefrom, said sleeve having an inner and an outer surface, the outer surface of the sleeve engaging in abutting relationship the inner surface of the cylindrical extension, the inner surface of the sleeve spaced apart from the outer surface of the bolt to define a radial clearance therewith; an external radially directed annular groove formed on said outer wrenching surface by the bolt head and the force ring, the external groove being less in axial width than twice the radial thickness between the bottom of the external groove and the inner surface of the sleeve thereby defining an annular section which plastically deforms radially inward with an essentially wedge-shaped cross section when a predetermined force acts on the bolt with resultant reduction of the axial width of the external groove.

Claim 11

The bolt of claim 8 wherein the outer surface of the sleeve of the force ring and the inner surface of the cylindrical extension of the bolt head are tapered.

Claim 12

The bolt of claim 8 wherein a flowable imcompressible material is disposed within the external groove.

Claim 13

The bolt of claim 10 wherein the material is electrically conducting.