Rock bolt overload warning device

Claim 2

A mine roof warning device comprising a washer having a base member with at least three corresponding rupturable angular finger like protrusions projecting from at least one surface thereof spaced at equal distances around the periphery of said base, with each of said corresponding respective protrusions having the same height.

Claim 3

The device of claim 1 wherein said angular protrusions comprise a plurality of singular rupturable projecting elements of varying heights spaced at equidistant intervals about the circumference of said washer base such that as said corresponding projections rupture there is always maintained a plane of contact defined by points of contact of at least three of said remaining projecting elements of the same height translated to the mine roof.

Claim 4

The device of claim 2 wherein those projecting elements not of the same height are spatially arranged in a stepwise manner around the periphery of the base of said washer.

Claim 5

The device of claim 2 wherein each of said corresponding projections or projecting elements having the same height are spaced 120° apart.

Claim 6

The device of claim 3 wherein said projections or projecting elements extend from the surface of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm.

Claim 7

A mine roof warning device comprising a washer having a base member with at least three stepped paired rupturable angular finger like projections extending from a surface of said base of said washer, said stepped paired projections being spaced at 120° around the periphery of said base, said projections extending from the surface of the base of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, wherein said at least three paired projections comprise corresponding projecting elements having the same height.

Claim 8

A mine roof warning device comprising a washer having a base member with at least three stepped paired rupturable angular finger like projections extending from a surface of said base of said washer, said stepped paired projections being spaced at 120° around the periphery of said base, said projections extending from the surface of the base of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, wherein said at least three paired projections comprise corresponding projecting elements having the same height.

Claim 9

A mine roof support fixture comprising in combination a roof plate, a bolt having a head and threaded portion, and a washer interpositioned between said plate and the head of said bolt, said washer comprising a base member with at least three corresponding rupturable angular finger like protrusions projecting from at least one surface thereof spaced at equal distances around the periphery of said base with each of said corresponding respective protrusions having the same dimension height.

Claim 10

A mine roof support fixture comprising in combination a roof plate, a bolt having a head and threaded portion, and a washer interpositioned between said plate and the head of said bolt, said washer comprising a base member with at least three corresponding rupturable angular finger like protrusions projecting from at least one surface thereof spaced at equal distances around the periphery of said base with each of said corresponding respective protrusions having the same dimension height.

Claim 11

The mine roof support fixture of claim 7 wherein said angular protrusions comprise a plurality of singular rupturable projecting elements of varying heights spaced at equidistant intervals about the circumference of said washer base, such that as said corresponding projections rupture a plane of contact defined by points of contact of at least three of said remaining projecting elements of the same height is always maintained with the surface of the head of said bolt.

Claim 12

The mine roof support fixture of claim 8 wherein those projecting elements not of the same height are spatially arranged in a stepwise manner around the periphery of the base of said washer.

Claim 13

The mine roof support fixture of claim 8 wherein each of the corresponding projections or projecting elements having the same height are spaced 120° apart.

Claim 14

The mine roof support fixture of claim 9 wherein said projections or projecting elements extend from the surface of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm.

Claim 15

The mine roof support fixture of claim 7 further including a flat washer interposed between said warning washer and said head of said bolt.

Claim 16

The device of claim 4, wherein said projections or projecting elements extend from the surface of said washer at an angle of about 60 degrees to a stepped height of from about 6 mm to 8 mm.

Claim 17

The mine roof support fixture of claim 10, wherein said projections or projecting elements extend from the surface of said washer at an angle of about 60 degrees to a height from about 6 mm to 8 mm.

Claim 18

The device of claim 2 wherein said plurality of singular projecting elements comprises at least three corresponding stepped paired projecting elements extending from said surface of said base member, said paired projecting elements being spaced at 120° around the periphery of said base member, said projecting elements extending from said surface at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, wherein said at least three stepped paired projecting elements comprise corresponding elements having the same height.

Claim 19

The mine roof support fixture of claim 8 wherein said plurality of singular projecting elements comprises at least three corresponding stepped paired projecting elements extending from said surface of said base member, said paired projecting elements being spaced at 120° around the periphery of said base member, said projecting elements extending from said surface at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, wherein said at least three stepped paired projecting elements comprise corresponding elements having the same height.

Claim 20

A mine roof warning device comprising a washer having a base member with six stepped paired rupturable angular finger like projecting elements extending from a surface of said washer, said stepped paired projecting elements being spaced at equal distances around the periphery of said base member with the alternate of said stepped paired projecting elements comprising corresponding elements of the same height spaced at 120° around the periphery of said base member, said projecting elements extending from the surface of the base of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, such that, as said corresponding projecting elements of the same height rupture, there is always maintained a plane of contact defined by points of contact of at least three of said remaining projecting elements of the same height translated to the mine roof.

Claim 21

A mine roof warning device comprising a washer having a base member with six stepped paired rupturable angular finger like projecting elements extending from a surface of said washer, said stepped paired projecting elements being spaced at equal distances around the periphery of said base member with the alternate of said stepped paired projecting elements comprising corresponding elements of the same height spaced at 120° around the periphery of said base member, said projecting elements extending from the surface of the base of said washer at an angle of about 60° to a stepped height of from about 6 mm to 8 mm, such that, as said corresponding projecting elements of the same height rupture, there is always maintained a plane of contact defined by points of contact of at least three of said remaining projecting elements of the same height translated to the mine roof.

Claim 22

The mine roof warning device of claim 1, wherein said washer comprises a material having a high modulus of elasticity.