Roof bolt anchor

An improvement in roof bolt anchors for securing a roof bolt within a hole preformed within a rock strata, said improvement comprising:

• (a) a plurality of stacked plastic leaves, each having an aperture therethrough in which said roof bolt is received and each being bent transversely to form a crest proximal said aperture and two inclined portions defining two curved edges on either side of said crest and adjacent a defining face of said hole;
• and
• (b) compression means threadably connected to said mine roof bolt for compressing said stacked plurality of plastic leaves to a flattened position such that said edges are urged laterally from said mine roof to engage said defining face and permeate said rock strata thereby gripping said strata and securing said mine roof bolt within said hole, wherein said compression means includes a support nut threadably connected to said roof bolt below, said stacked plurality of plastic leaves;
• a stirrup loosely engaging said mine roof bolt and supported by said support nut for supporting said stacked plurality of plastic leaves, said stirrup having two vertical members extending alongside said plurality of leaves on opposite sides thereof and in snugly received abutment with said defining face such that said stirrup does not rotate responsive to the rotation of said mine roof bolt when received within said hole;
• and a compression nut movably connected to said mine roof bolt superjacent said stacked plurality of plastic leaves and seated intermediate and in nonrotating relation to said vertical members, such that rotation of said mine roof bolt in a selected direction will urge said compression nut downwardly to compress said stacked plurality of plastic leaves against said supporting stirrup and into said flattened position, wherein said compression nut includes a horizontal member slidably connected to said bolt and supported thereon by said plurality of plastic leaves, wherein said horizontal member has a pair of opposing flanges integrally connected to opposing margins thereof and extending downwardly therefrom in substantially normal relation thereto, wherein said compression nut further includes an upper portion threadably connected to said bolt superjacent said horizontal member, such that rotation of said bolt in a selected direction will urge said upper portion downwardly against said horizontal member to compress said plurality of plastic leaves adjacent said support means to reduce the inclination of said inclined portions and thereby urge said curved edges from said roof bolt and against said defining face of said hole.

An improvement in roof bolt anchors for securing a mine roof bolt within a hole preformed within a rock strata, said improvement comprising:

• (a) a stacked plurality of plastic leaves each having a central aperture therethrough in which said roof bolt is received and each being bent transversely proximal to said central aperture to form a pair of inclined portions connected at and forming a common crest and defining two opposing curved edges adjacent a defining face of said hole;
• (b) support means connected to said bolt below said stacked plurality of leaves for supporting said plurality of leaves and maintaining a minimal inclination of said inclined portions;
• (c) a horizontal member having an aperture therethrough through which said bolt is slidably received wherein said horizontal member is supported by said plurality of leaves and includes a pair of downwardly extending flanges integrally connected thereto;
• and
• (d) a biasing member threadably connected to said roof bolt above and adjacent to said horizontal member for urging said horizontal member and flanges thereon downwardly against said plurality of plastic leaves responsive to rotation of said roof bolt to compress said plastic leaves against said support means to reduce the inclination of said inclined portions and thereby urge said curved edges from said roof bolt and against said defining face of said hole.