Earth structure stabilizer

Claim 1

An improved earth structure stabilizer, for insertion into a bore formed in an earth structure such as a roof or side wall of a mine shaft, or tunnel, or a like subterranean opening, for frictionally stabilizing such earth structure, said stabilizer comprising an elongate element having a length taken from, and comprised by, a range of lengths of from two and a half feet to six or more feet, and having a generally annular cross-section of a given, free, and single outside diameter, and formed of material of one uniform thickness, responsive to circumferential compression to facilitate a diminution of said given diameter to another, compressed, outside diameter, whereby said stabilizer can be inserted into and received by an earth structure bore having a diameter generally approximating said another diameter, to cause said stabilizer to engage the surface of such bore and frictionally anchor therewith, to stabilize the earth structure in which such stabilizer-receiving bore is formed, wherein the improvement comprises: stiffener means, of substantially uniform dimension and conformation, extending lengthwise of said element, and projecting radially inwardly thereof only, for stiffening said stabilizer elongatedly; wherein said stiffener means comprises means for diminishing compression resistance of said element circumferentially thereof; said resistance-diminishing means comprises a plurality of circumferentially and substantially uniformly spaced-apart channels formed in the outside surface of said element and extending lengthwise thereof; and each of said channels includes side wall which are spaced apart to define an open cove or recess, in said outside surface, the radially outermost area of which occupies approximately between five and six degrees of arc, said coves or recesses defining means for permitting said stabilizer to be circumferentially compressed in order that it may fit into a smaller earth bore.