Mine roof bolt anchor construction

Claim 2

Mine roof bolt anchor construction including: a. a bolt having a threaded shank portion; b. a camming plug threadably engaged with said bolt for advancement along the threaded shank portion; c. an expansion shell mounted on the bolt; d. the expansion shell including a plurality of metal fingers surrounding the bolt and engageable with the camming plug; e. the fingers each having a free end and outer, inner and side surfaces; f. a series of teeth coined in each of said fingers and projecting outwardly from the outer finger surface; g. each finger inner surface having a pair of spaced generally planar bearing strips extending longitudinally adjacent the finger side surfaces engageable with the camming plug, and a single rectangular planar surface extending between said bearing strips; h. the rectangular planar surface being tapered from the finger free end outwardly away from the bearing strips, and the teeth being coined from finger material displaced in forming said tapered planar surface, with the rectangular planar surface constituting a smooth back surface for the series of teeth and forming the entire area between the spaced bearing strips; i. the majority of the teeth include major planar facets extending outwardly downwardly with respect to the outer finger surface and minor planar facets extending outwardly upwardly with respect to the outer finger surface; j. and tooth crests being formed by the junctions of said major and minor planar facets and extending transversely with respect to the shell fingers.

Claim 3

The construction defined in claim 1 in which the fingers each terminate at an end opposite of the finger free end in a collar, and in which each finger includes a stem portion extending between said collar and the teeth.

Claim 4

The construction defined in claim 2 in which the rectangular planar teeth back surface of each finger extends between the outer free end of the finger and the stem portion.

Claim 5

The construction defined in claim 3 in which a rounded shoulder extends between the teeth back surface and stem portion of each shell finger.

Claim 6

The construction defined in claim 2 in which the metal thicknesses of the collar, stem portions, and bearing strips are generally equal; and in which said thicknesses are generally equal to the thickness of a virgin metal strip from which the expansion shell is formed.

Claim 7

The construction defined in claim 1 in which the thicknesses of the teeth measured along corresponding radial lines generally are equal.

Claim 8

The construction defined in claim 1 in which the teeth crests terminate in generally outwardly flared, rounded ends.

Claim 9

An expansion shell for a mine roof bolt anchor construction of the type having a bolt with a threaded shank portion, in which a camming plug is threadably engaged with the bolt, in which the expansion shell is telescopically mounted on the bolt and engageable with the camming plug, and in which the shell is expanded outwardly upon advancement of the plug along the threaded shank portion within the expansion shell; the expansion shell including: a. a collar and a plurality of metal fingers extending from said collar; b. the fingers each having a free end and outer, inner and side surfaces; c. a series of teeth coined in each of said fingers and projecting outwardly from the outer finger surface; d. each finger inner surface having a pair of spaced generally planar bearing strips extending longitudinally adjacent the finger side surfaces engageable with the camming plug, and a single rectangular planar surface extending between the bearing strips; e. the rectangular planar surface being tapered from the free finger end outwardly away from the bearing strips and forming the entire area between the spaced bearing strips and constituting a smooth back surface of the series of teeth, with the teeth being formed from finger material displaced in forming the planar back surface; f. certain of the teeth each includes a major planar facet extending outwardly downwardly with respect to the outer finger surface and a minor planar facet extending outwardly upwardly with respect to the outer finger surface; g. and tooth crests being formed by the junction of said major and minor planar facets, with the metal thicknesses of certain teeth crests being equal.

Claim 10

An expansion shell for a mine roof bolt anchor construction of the type having a bolt with a threaded shank portion, in which a camming plug is threadably engaged with the bolt, in which the expansion shell is telescopically mounted on the bolt and engageable with the camming plug, and in which the shell is expanded outwardly upon advancement of the plug along the threaded shank portion within the expansion shell; the expansion shell including: a. a collar and a plurality of metal fingers extending from said collar; b. the fingers each having a free end and outer, inner and side surfaces; c. a series of teeth coined in each of said fingers and projecting outwardly from the outer finger surface; d. each finger inner surface having a pair of spaced generally planar bearing strips extending longitudinally adjacent the finger side surfaces engageable with the camming plug, and a single rectangular planar surface extending between the bearing strips; e. the rectangular planar surface being tapered from the free finger end outwardly away from the bearing strips and forming the entire area between the spaced bearing strips and constituting a smooth back surface of the series of teeth, with the teeth being formed from finger material displaced in forming the planar back surface; f. certain of the teeth each includes a major planar facet extending outwardly downwardly with respect to the outer finger surface and a minor planar facet extending outwardly upwardly with respect to the outer finger surface; g. and tooth crests being formed by the junction of said major and minor planar facets, with the metal thicknesses of certain teeth crests being equal.

Claim 11

The construction defined in claim 8 in which the metal thicknesses of the collar, stem portions, and bearing strips are generally equal; and in which said thicknesses are generally equal to the thickness of a virgin metal strip from which the expansion shell is formed.

Claim 12

The construction defined in claim 8 in which the teeth crests terminate in generally outwardly flared, rounded ends.

Claim 13

The construction defined in claim 8 in which a rounded shoulder extends between the teeth back surface and stem portion of each shell finger.