1. Field of the Invention
This invention relates to a truss shoe for use with a threaded rod and, more particularly, to a truss shoe having a threaded passageway to receive an end portion of the threaded rod; the truss shoe having a stop member spaced from an exit end of the threaded passageway to pass the end of the threaded rod past the exit end of the passageway for full thread engagement of the threaded passageway.
2. Discussion of the Presently Available Technology
Truss-type mine roof supports are well known in the art of supporting the roof of an underground passageway, such as a mine passage. A basic truss system includes one or more threaded rods extending horizontally the width of the mine passage adjacent the roof and connected at their ends to anchor bolts, which extend at an angle adjacent the ribs of the passage into the rock strata over a solid pillar. The rods are tensioned and vertical components of compressive forces are transmitted into the rock strata over the solid pillars, as opposed to the unsupported rock strata immediately above the passage.
With this arrangement, a truss system shifts the weight of the rock strata from over the mined-out passage back onto the pillars. Conventionally, holes are drilled into the mine roof at a 45° angle from the horizontal adjacent to the mine rib so that the holes extend into the supported rock strata over a pillar.
Once the holes are drilled at an angle into the strata over the pillars at the rib line, anchor bolts are inserted into the drilled holes and are secured in place using mechanical expansion shell assemblies and/or a resin made from a mixture of a resin component and an epoxy component. Before the bolts are inserted in the drilled holes, truss shoes are positioned on the bolt at the emergent end of the bolt from the hole. As the bolts are securely anchored in the drilled holes, the bearing surfaces of the truss shoes are compressed into engagement with the mine roof.
For an uneven mine roof or a roof having severely potted areas, the truss shoe preferably has sufficient bearing surface to contact the mine roof so that the truss shoe is correctly positioned for engagement with the horizontal truss members. Once the truss shoes are securely positioned at the mine roof adjacent the ribs, the horizontal truss members are assembled and connected to the truss shoes. Horizontal truss members are tightened to a predetermined tensioning load so that the weight of the rock strata over the mined-out area beneath the roof can shift along the horizontal truss members upwardly into the solid rock strata over the pillars at the rib line.
The truss hardware is connected under tension to the truss shoes that are held tightly against the mine roof by the anchored angle bolts. A wide variety of truss hardware is commercially available to form a truss system between the anchored angle bolts. For example and not limiting to the discussion, U.S. Pat. No. 7,261,494 (hereinafter also referred to as “USPN '494”) and U.S. Pat. No. 8,057,128 (hereinafter also referred to as “USPN '128”), both of which are assigned to FCI Holdings Delaware, Inc., disclose a cable truss system including a pair of truss shoes, a pair of inclined bolts, and a truss assembly. In general, the truss shoes of USPNs '494 and '128 include a bolt receiving end portion to receive the bolt that attaches the truss shoe to the ceiling or roof, and an opposite cable receiving and retaining end portion to receive an end of a cable to secure the cable to the truss shoe. The cable receiving and retaining end portion includes a tapered passageway for receiving a wedge or cone-shaped retention assembly.
The retention assembly is secured in the passageway by a washer (USPN '494) or a locking tube (USPN '128). The truss shoes of USPNs '494 and '128 are acceptable for use with truss systems that connect the truss shoes with cables, but, as can be appreciated by those skilled in the art, they are not used with truss systems that interconnect the truss shoes with threaded rods.
Truss shoes are available for use with truss systems connecting the truss shoes with threaded rods; however, the truss shoes that are interconnected by threaded bars have limitations. By way of illustration and not limited thereto, a stop member is provided at the exit end of a threaded passageway of the truss shoe. The stop member prevents the end of the threaded rod from passing through the threaded passageway, thereby preventing the threaded passageway of the truss shoe from being fully threaded on the threaded rod.
As can be appreciated by those skilled in the art, it would be advantageous to provide a truss shoe designed to permit a threaded rod to pass through the exit end of a threaded passageway of the truss shoe to provide full thread engagement of the threaded passageway by the threaded rod.
This invention relates to a method of securing a threaded rod in a truss shoe of a mine roof support assembly by, among other things, providing a truss shoe including, among other things, a one-piece body member having a base member having a bearing surface, an opposite surface having a bolt receiving section, a housing spaced from the bolt receiving section, and a stop member; the bolt receiving section having a retention hole; the housing having a passageway, the passageway having a first open end facing the bolt receiving section, an opposite second open end, and a threaded portion extending from the first open end of the passageway toward the second open end, and the stop member positioned between the bolt receiving section and the housing, and spaced from the first open end of the passageway. The threaded rod is moved through the second open end of the passageway to move the first end of the threaded rod through the threaded portion of the passageway, out of the first open end of the passageway and through the space between the first open end of the passageway and the stop member into engagement with the stop member, wherein all of the threads of the threaded portion of the passageway are in facing relationship to the threads of the threaded bar.
Further, this invention relates to a truss shoe for use in a mine roof support system, the truss shoe includes, among other things, a one-piece body member including, among other things, a base member having a bearing surface; an opposite surface having a bolt receiving section, the bolt receiving section having a retention hole; a housing spaced from the bolt receiving section, the housing having a passageway, the passageway having a first open end facing the bolt receiving section, an opposite second open end, and a threaded portion extending from the first open end of the passageway toward the second open end, and a stop member, the stop member positioned between the bolt receiving section and the housing, and spaced from the first open end of the passageway, whereby moving the threaded rod through the second open end of the passageway moves the first end of the threaded rod through the threaded portion of the passageway, out of the first open end of the passageway and through the space between the first open end of the passageway and the stop member into engagement with the stop member.
A complete understanding of the invention will be obtained from the following description when taken in connection with the accompanying drawing figures, wherein, unless indicated otherwise, like reference characters identify like parts throughout. Further, the terminology used herein to discuss the non-limiting embodiments of the invention is for purposes of description and not of limitation.
For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, and derivatives thereof, shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention can assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary non-limiting embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. Further, all numbers expressing dimensions, physical characteristics, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims can vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between, and inclusive of, the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less, e.g., 1 to 6.7, or 3.2 to 8.1, or 5.5 to 10.
Referring to
As is appreciated, the truss system incorporating features of the invention is not limited to providing an uplifting force to the roof 12 of the passageway 14 and can be used to apply a supporting force to the sidewalls 18 and 20.
With continued reference to
One non-limiting roof bolt assembly, e.g., roof bolt assembly 28, that can be used in the practice of the invention and not limiting the invention thereto, includes an elongated roof bolt, e.g., elongated roof bolt 31, having an enlarged head, e.g., nut 33, at one end portion 34, a washer 36 between the enlarged head 33 of the roof bolt 31 and the truss shoe 27, and an opposite threaded end portion 38. A mechanical expansion shell assembly 40 is threadably engaged to the threaded end portion 38 of the bolt 31. As is well known in the art, upon rotation of the roof bolt 31, the shell assembly 40 is expanded into gripping engagement with the wall of the bore hole 29 to exert tension on the elongated roof bolt 31, with the end portion 34 of the bolt 31 bearing against the mine roof 12. To increase the anchorage of the elongated roof bolt 31 of the roof bolt assembly 28 within the bore hole 29, resin can be used in combination with the roof bolt assembly 28 when it is installed, e.g. but not limiting to the invention, as disclosed in U.S. Pat. No. 6,619,888 (hereinafter also referred to as “USPN '888”), incorporated by reference. The use of resin adds additional strength to the anchorage of the roof bolt 31 of the roof bolt assembly 28 in its respective one of the bore holes 29 when torque is applied to the end portion 34 of the roof bolt 31.
With continued reference to
With reference to
The invention is not limited to the shape or the dimensions of the side ribs 70 and 72, however, the side ribs 70 and 72 should be sized to provide structural stability to the truss shoe 27, for example and not limiting to the invention, to prevent bending of the truss shoe 27 at a position between the bolt receiving section 64 and the threaded rod receiving or engaging section 66 (see
Prior to installation of the elongated roof bolt assembly 28 in the bore hole 29 in the rock formation 16, the end portion 38 of the roof bolt 31 is moved through a bolt retention hole 76 in the bolt receiving section 64 of the truss shoe 27, with the enlarged head 33 of the roof bolt 31 and the washer 36 engaging an open end 78 of the bolt retention hole 76 of the truss shoe 27. The expansion shell assembly 40 can be threaded onto the threaded end portion 38 of the roof bolt 31 before the roof bolt 31 is moved through the retention hole 76 of the truss shoe 27, or after the roof bolt 31 is moved through the retention hole 76 of the truss shoe 27. The roof bolt 31 having the expansion shell assembly 40 is then inserted upwardly into the angled bore hole 29 in the rock formation 16. The roof bolt assembly 28 is advanced into the bore hole 29 so that the enlarged head 33 of the bolt 31 moves the washer 36 against the open end 78 of the retention hole 76 of the truss shoe 27 to urge the bearing surface 62 of the truss shoe 27 (see
As can be appreciated, the invention is not limited to the manner in which the truss shoe of the invention is secured against the roof 12 of the passageway 14 (see
With continued reference to
With continued reference to
The threaded rod engaging section 66 of the truss shoe 27 includes a housing 90 extending upwardly or outwardly from the base 60 of the truss shoe 27. In one non-limiting embodiment of the invention, the housing 90 has a rounded outer upper surface 92 (clearly shown in
With reference to
As is appreciated by those skilled in the art, the invention is not limited to the dimensions of the passageway 94 and the height of the riser 112. In one non-limiting embodiment of the invention, the length of the threaded portion 100 of the passageway 94 was 2.37 inches, and the length of the cone-shaped portion 102 was 1 inch. The passageway 94 at the position 104 had a diameter of 1.148 inches, at the first open end 96 a diameter of 1.148 inches, and at the second end 98 a diameter of 0.995 inch. The threads of the threaded portion 100 of the passageway 94 is not limiting to the invention and are sized to received the threaded bar, and the riser 112 had a height of 0.875 inch as measured from the bearing surface 62 of the truss shoe 27, and a centerline 118 of the threaded portion 100 of the passageway 94 is spaced 1.14 inches from the bearing surface 62 of the truss shoe 27.
In the preferred embodiment of the invention, the truss shoe 27 having the base 60, the bolt receiving section 64, the intermediate body section 68, and the threaded rod engaging section 66 is a formed, one-piece truss shoe 27 (see
As can be appreciated, the invention is not limited to the dimensions of the truss shoe 27 of the invention, and the truss shoe should be large enough to provide a bearing surface 62 having an area sufficient to span recesses in the roof 12 (see
With reference to
In general, the truss system 10 using the truss shoe 27 of the invention is assembled in any convenient manner. For example but not limiting to the invention, the elongated roof bolt assemblies 28 are mounted in the roof 12 as discussed above, and the truss shoe 27 is secured on the roof bolt 31 by passing the roof bolt 31 through the retention hole 76 of the truss shoe 27 and securing the enlarged head 33 and washer 36 on the end of the bolt 31 as discussed above (see
The opposite ends 44 of the threaded bars 42 are joined to the coupler 46 (see
It will be understood by those skilled in the art that while the foregoing description set forth in the detailed non-limiting preferred embodiments of the present invention, modifications, additions, and changes can be made thereto without departing from the spirit and scope of the invention as set forth in the following claims.
Number | Date | Country | |
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61585850 | Jan 2012 | US |