Railway rolling stock – Special car bodies – Dumping
Patent
1994-10-19
1995-10-17
Reese, Randolph A.
Railway rolling stock
Special car bodies
Dumping
4052591, 4052595, E21D 2000
Patent
active
054584426
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the tensile reinforcing members, known as "roof bolts", which are used in underground mining operations for the purpose of stabilisation of the rock strata, for example roof support when tunnelling.
In service the bolts are used in a procedure which comprises:
a) boring holes into the rock strata;
b) introducing bolts which extend axially along the length of the holes; and
c) injecting a settable grouting material into each hole so as to substantially fill the voids between the bolt and the hole.
The depth and direction of the holes are designed so that the bolt extends from potentially unstable rock strata into areas of rock which are known to be stable, thus stabilising the rock (e.g. the roof) which was liable to collapse. This objective may be further advanced by attaching a nut and washer to the inboard end of the bolt so that it directly bears upon and supports the inner rock face. After the grouting material has hardened, the nut may be tightened so as to pre-tension the bolt.
The present invention provides a flexible roof bolt comprising a hollow, stranded rope with a load-bearing termination at one end which is provided with an internal bore (for fluid injection purposes) and an external thread (for tensioning purposes). The hollow rope consists of a plurality of strands extending helically around a central void. Each strand comprises a helically spun assembly of wires. The termination engages an end portion of the rope, and its internal bore communicates with the central void of the rope.
The external surface of the termination may also be advantageously provided with one or more flats (for gripping purposes) and an annular sealing means.
The invention will be described further, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a side view of a flexible roof bolt;
FIG. 2 is a section on line II--II in FIG. 1;
FIGS. 3 and 4 are respectively an elevation and a side view of a bearing plate; and
FIG. 5 is an enlarged axial section through one end of the roof bolt.
A ductile steel cylindrical fitting 1 has a hollow bore 11 extending the full length of it. The bore 11 at the right hand extremity is threaded internally at 12 to accept a connector for fluid injection purposes, and the bore 11 at the left hand end is enlarged at 13 to accept a wire rope 3 or flexible strength member. After introducing the wire rope 3 into this cavity 13, the left-hand shank 14 of the fitting 1 is deformed radially inwards (e.g. by pressing or swaging) using hardened steel dies to effect a permanent interference with, and gripping of the rope 3. The external profile imparted by the dies may be circular or polygonal in cross-section, but a preferred octagonal profile is illustrated in FIG. 2, which also shows an optional liner 18 of softer metal more ductile than the body 19 of the fitting 1. The right-hand end of the fitting is provided externally with a helical thread 16, which will accept a tensioning nut (not shown) capable of transmitting the full tensile strength of the assembly.
A sealing ring 2 of elastically deformable material is located in a shallow circular groove 17 in the fitting 1, and projects above the thread 16 and die-formed shank 14 of the fitting. In use the ring 2 serves to block the annular space between the fitting 1 and the walls of the hole in the rock face.
The rope 3 is a hollow steel wire rope, preferable of six-strand construction and more preferably 6.times.7 (6/1) or similar design, typically with a length of 5, 6, 8, or up to 10 m, although longer lengths may be used if required. The hollow rope may be manufactured for example in accordance with the teachings of U.K. Patent specification 1 373 814, wherein the strands may additionally be compacted or may be deformed into one another during manufacture, where it is desired to provide a more dense and rigid member. This would be particularly advantageous where long lengths of flexible bolting are required, since the premature escape of grouting material will be inhibited.
A beari
REFERENCES:
patent: 3311012 (1967-03-01), Williams
patent: 3389561 (1968-06-01), Taylor
patent: 4139323 (1979-02-01), Brandstetter
Bridon PLC
Lagman Frederick L.
Reese Randolph A.
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