Telescopic mine roof support

Abstract

A longitudinally yieldable support for underground roof support includes a first support section with a first elongate outer shell filled with a solid compressible filler material and a second support section filled with a second solid compressible filler material with a second elongate outer shell extending above the first elongate outer shell. The second support section has density that is greater than a density of the first solid compressible filler material. A pair of attachment members are coupled to the second elongate outer shell and are configured for lifting the second elongate outer shell relative to the first elongate outer shell and for securing the second elongate outer shell relative to the first elongate outer shell once lifted.

What is claimed is: 
     
         1 . A longitudinally yieldable support, comprising:
 a first support section comprising a first elongate outer shell filled with a first solid compressible filler material; and   a second support section comprising a second elongate outer shell extending above the first elongate outer shell, the second elongate outer shell having an outer diameter that is different than a diameter of the first elongate outer shell to allow the second elongate outer shell to slide relative to the first elongate outer shell, and the second elongate outer shell filled with a second solid compressible filler material having a density that is at least as great as a density of the first solid compressible filler material.   
     
     
         2 . The support of  claim 1 , further comprising a pair of attachment members coupled to the second elongate outer shell configured for lifting the second elongate outer shell relative to the first elongate outer shell and configured for securing the second elongate outer shell relative to the first elongate outer shell once lifted. 
     
     
         3 . The support of  claim 1 , wherein the first elongate outer shell is comprised of steel and wherein the first solid compressible filler material is cast in the first elongate outer shell. 
     
     
         4 . The support of  claim 3 , wherein the second elongate outer shell is comprised of steel and is movable from a first position in which the second elongate outer shell is at least partially disposed within the first elongate outer shell to a second position in which a portion of the second elongate outer shell is positionable between the first elongate outer shell and a roof of a mine entry with a lower portion of the second elongate outer shell disposed within the first elongate outer shell. 
     
     
         5 . The support of  claim 1 , wherein the second elongate outer shell is comprised of steel and is movable from a first position in which the second elongate outer shell is at least partially disposed over the first elongate outer shell to a second position in which a portion of the second elongate outer shell is positionable between the first elongate outer shell and a roof of a mine entry with a lower portion of the second elongate outer shell disposed over the first elongate outer shell. 
     
     
         6 . The support of  claim 1 , wherein the first compressible filler material has a first density and the second compressible filler material is comprised of a solidified compressible material having a second density that is greater than the first density of the first compressible filler material. 
     
     
         7 . The support of  claim 2 , wherein the pair of attachment members are each comprised of an elongate strap that is coupled to the second elongate outer shell by wrapping around a lower end thereof and further comprises a securing portion for securing the second elongate outer shell relative to the first elongate outer shell. 
     
     
         8 . The support of  claim 7 , wherein the securing portion of each of the pair of attachment members laterally extends relative to a top end of the second elongate outer shell and is configured for attachment to a roof. 
     
     
         9 . The support of  claim 7 , wherein each of the pair of attachment members are bent over a top edge of the first elongate outer shell to maintain the second elongate outer shell relative to the first elongate outer shell. 
     
     
         10 . The support of  claim 6 , wherein the first compressible filler material has a density of between about 40 and 50 lb/ft 3  and the second compressible filler material has a density of between about 50 and 60 lb/ft 3 . 
     
     
         11 . The support of  claim 1 , wherein the first support section will yield first under load until a first yield limit is reached at which time the second support section will begin to yield. 
     
     
         12 . The support of  claim 1 , wherein the first support section is capable of supporting a load of at least 100,000 lbs. 
     
     
         13 . The support of  claim 11 , wherein the first support section is capable of supporting a load of between approximately 100,000 lbs and 300,000 lbs as the first support section yields under load. 
     
     
         14 . The support of  claim 10 , wherein the second outer shell will fold upon itself as the second support section yields. 
     
     
         15 . A longitudinally yieldable support for supporting a roof in an underground mine, comprising:
 a first support section comprising a first elongate outer shell comprised of metal filled with a first solidified compressible filler material;   a second support section comprising a second elongate outer shell comprised of metal extending above the first elongate outer shell, the second elongate outer shell having an outer diameter that is small than a diameter of the first elongate outer shell to allow the second elongate outer shell to slide relative to the first elongate outer shell, the second elongate outer shell filled with a second solidified compressible filler material; and   a pair of attachment members coupled to the second elongate outer shell configured for securing the second elongate outer shell relative to the first elongate outer shell once lifted.   
     
     
         16 . The support of  claim 15 , wherein the second elongate outer shell is movable from a first position in which the second elongate outer shell is substantially disposed within the first elongate outer shell to a second position in which a portion of the second elongate outer shell is positionable between the first elongate outer shell and a roof of a mine entry with a lower portion of the second elongate outer shell disposed within the first elongate outer shell. 
     
     
         17 . The support of  claim 15 , wherein the second elongate outer shell is movable from a first position in which the second elongate outer shell is at least partially disposed over the first elongate outer shell to a second position in which a portion of the second elongate outer shell is positionable between the first elongate outer shell and a roof of a mine entry with a lower portion of the second elongate outer shell disposed over the first elongate outer shell. 
     
     
         18 . The support of  claim 15 , wherein the first compressible filler material has a first density and the second compressible filler material has a second density that is greater than the first density of the first compressible filler material. 
     
     
         19 . The support of  claim 15 , wherein the pair of attachment members are each comprised of an elongate metal strap that is coupled to the second elongate outer shell by wrapping around a lower end thereof and further comprises a securing portion for securing the second elongate outer shell relative to the first elongate outer shell. 
     
     
         20 . The support of  claim 19 , wherein the securing portion of each of the pair of attachment members laterally extends relative to a top end of the second elongate outer shell and includes a hole configured for attaching the securing portion to a mine roof. 
     
     
         21 . The support of  claim 19 , wherein each of the pair of attachment members are bent over a top edge of the first elongate outer shell to maintain the second elongate outer shell relative to the first elongate outer shell. 
     
     
         22 . The support of  claim 15 , wherein the first support section is configured to yield under load until a first yield limit is reached at which time the second support section will begin to yield. 
     
     
         23 . The support of  claim 22 , wherein the second outer shell is configured to fold upon itself as the second support section yields.