GB2130272A - Improvements in or relating to mine arch constructions - Google Patents

Abstract

A mine arch construction comprises first and second load-bearing frame members to which are secured a plurality of ribbed deck members so as to define an elongate open-ended enclosure. The frame members have outwardly projecting threaded stud members (40 Fig. 4) which pass through openings in the deck and co-operate with retainer members to secure the assembly. A sheet metal nut member (84, Fig. 10) may be employed to permit relative sliding securement of the nut member to the threaded stud, while resisting relative sliding removal thereof. Male and female lateral edges facilitate joinder of adjacent panel edges and may be provided with gasket materials so as to resist leakage of air through the joint. The assembly which is adapted for disassembly and reuse may advantageously be employed as a mine overcast, as well as for other mine uses. <IMAGE>

Description

SPECIFICATION Improvements in or relating to mine arch constructions This invention relates to a mine arch construction and, more specifically, to a prefabricated construction which is adapted for advantageous use as a mine overcast.

In connection with underground mining activities, such as in coal mines, it is necessary to provide effective ventilation in order to supply fresh air to miners working in the mine and to dilute and remove methane, carbon dioxide, dust particles and other noxious gases.

Where mine passageways intersect and it is desired that one passageway has a supply of fresh air and that the other contains contaminated, return air, it is necessary to provide discrete passageways in order that the two streams of air cannot comingle. It is known to accomplish this objective through the use of an overcast.

In one known form of overcast, a pair of cinderblock walls are constructed adjacent to passageway walls in a first passageway and a plurality of spaced beams, having opposed ends supported on the walls with block or other materials, are employed to define an elongate air passageway. An intersecting passageway passes over the first passageway. In general, a pair of spaced block walls will be so positioned over the first enclosed passageway as to define the lateral limits of the intersecting passageway as it extends over the first passageway. In this fashion, air flowing in either passageway is kept separate from air flowing in the other passageway. Among the problems with such a block and beam overcast are the fact that they are labour intensive, very difficult to make airtight and require the services of skilled labour for masonry work, etc.In addition, they are not particularly strong and do not readily accommodate movement of the underlying and overlying strata which will tend to shift with the passage of time. Further, such constructions are brittle in nature, crack easily and, as a result, tend to develop leaks. Cracking is further enhanced through deflection of the support beams.

It is also known to provide prefabricated overcasts wherein plates which function as a load-bearing skin are assembled to provide an enclosure. See generally, Armco Liner Plate catalogue CP-7880 and Lane Metal Products Company, Inc. catalogue entitled "Corrugated Steel Products Mine Overcast". One of the difficulties with such liner plate assemblies is that the material costs are generally substantially higher than those of the block and beam overcast. In general, they are no stronger than block and beam overcasts.

It is also known to employ a plurality of arch shape support members in combination with metal deck members to establish an overcast, for example, see Stratabolt catalogue entitled "Flowline Prefabricated Overcasts". Constructions of this general type, however, have required the handling of a large number of independent fasteners or reliance on less effective fastening means, and have been found not to provide the strength and air seals desired.

There remains, therefore, a substantial need for an improved mine arch construction.

Thus, the invention provides a mine arch construction comprising: a first load-bearing generally arch-shaped frame member and a second load-bearing generally arch-shaped frame member spaced from and disposed generally parallel to said first frame member, each said frame member having a number of outwardly projecting, externally threaded stud members secured thereto; a plurality of deck members, having alternating ribs and valleys, secured to said frame members to define an open-ended enclosure, said threaded stud members passing through said deck members, and having retainer means secured to said stud means to retain said deck members in place.

Preferably, said retainer means comprise nut means that are adapted to be removed from said stud means by unthreading.

The mine arch construction may be adapted to be disposed in a mine passageway intersection to form a mine overcast. In this case a first ventilation passageway may be defined by said mine arch construction in cooperation with the underlying floor of the mine passageway, and a pair of spaced wall means may be disposed between said metal deck members and the passageway walls and roof to define a second ventilation passage oriented generally transversely with respect to said first ventilation passageway.

Desirably, said retainer means is a sheet-like nut member having resiliently deformable portions that permit securement of the retainer means to said stud members by relative sliding movement thereover but resist removal by relative sliding movement, and preferably, said nut member engages with the thread of said stud member when in a secured position and is adapted for removal therefrom by unthreading.

Preferably, said nut member has a generally downwardly concave shape, and a pair of opposed generally upwardly and inwardly projecting cantilevered tabs co-operate with a pair of opposed lateral walls to define a central opening. Said cantilevered tabs may each have a generally V-shaped notch adjacent said central opening.

Preferably, said deck members are metal, lateral edges of adjacent said deck members having mating male and female flanges in engagement to establish a joint therebetween, and said stud passes through a preformed opening in a valley portion of each of said adjacent deck members generally adjacent to said male-female joint. Said male flange may be generally upwardly projecting, and said female flange generally upwardly projecting to terminate in a downwardly extending reentrant portion to define a channel, that is adapted to receive said male flange.

Desirably, said deck ribs further comprise a plurality of integrally formed surface irregularities and a coating of sealant material is secured to said metal deck over said irregularities.

Gasket means may also be disposed between adjacent deck members.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an elevational view of a form of frame member used in a mine arch construction in accordance with the present invention; Figure 2 is a perspective view of a mine arch construction of the present invention in the process of assembly or disassembly; Figure 3 is a partial elevation view showing a section of a mine arch construction of the present invention; Figure 4 is a fragmentary view showing a portion of a frame member; Figures 5 and 6 show respectively, a front elevation and a cross-sectional view through VI-VI of Fig. 5 of a component of a frame member; Figure 7 is an elevational view showing another form of frame member component;; Figure 8 is a front elevational view of another frame member component: Figure 9 is a right-side elevational view of the frame member component of Fig. 8; Figure loins a fragmentary illustration of a type of metal deck joint employed in the present invention; Figure ii is a top plan view of one form of nut used in the present invention; Figure 12 is a front elevational view of the nut of Fig. 11.

Figure 13 is a side elevational view of the nut of Fig. 11; Figure 14 is a bottom plan view of the nut of Fig. 11; and Figures 15 and 16 illustrate, respectively, the male and female lateral edges of metal deck members used in a construction of the invention.

When used herein, the term "arch" is intended to refer not only to traditional curved arch shapes, but also to other frames having an inverted generally U-shape, including frames having one or more generally vertical sections and a top section having generally horizontal portions.

As will be discussed in detail below, Fig. 1 shows the structural framework which will form a frame member 9 employed in the present invention, that comprises a lower frame segment 2, intermediate beam segments 4 and 6 and upper segments 8. It will be appreciated that, in general, the mine arch construction of the present invention may be considered to consist of a load-bearing skeleton and associated deck members. The skeleton may be a structural steel framework assembled from a plurality of I-beam, H-beam or tubular segments, which may be secured to each other, by nuts and bolts which are passed through aligned flanges at or adjacent the ends of the frame segments. The metal deck members may conveniently be corrugated galvanized steel or aluminium.For convenience of disclosure, the region confined within the frame member 9 will be referred to as the "inside" 10 and the region exterior to the frame member 9 will be referred to as the "outside" 1 2.

Referring to Fig. 2, a mine arch construction, that is illustrated in a partially completed state, comprises a second frame member 14 spaced from and disposed generally parallel to a first frame member 9, the frame members 9, 1 4 being joined together by a strut member 1 6 which has one of its ends secured to each frame member 9, 14. The strut member 1 6 is not essential to the final structure but does facilitate erection of the construction.

The frame members 9, 10 have a height H and are spaced from each other at a distance X. While it will be appreciated that a wide variety of dimensions may be employed without departing from the present invention, it is generally preferred to employ a height H that is about equal to the seam height. For certain uses this may be about 3 to 8 feet (1 to 2.5 m). Spacing X may be about 4 to 14 feet (1.2 to 4.3 m), and will generally be related to deck strength and load. Also, in some circumstances it may be desirable to employ three or more such frame members with the additional frame members being spaced from and parallel to the first or second frame member.

Still referring to Fig. 2 a pair of elongate metal deck members 24, which have a plurality of alternating ribs 26 and valleys 28, are provided. Each metal deck member 24 has its ends secured, respectively, to one of the frame members 9, 14.

Where, as illustrated in Fig. 2, a third frame member is provided, for example spaced from the frame member 14, its metal deck member 24 has its ends secured to frame member 14 and to the additional frame member, with adjacent edges of the two deck members overlapped. it will be noted that the ribs 26 are generally horizontally oriented, as would also be the case for the remaining portions of the frame member shown, when the metal deck members are in place. It will be appreciated that the final structure will have a com plete covering of the frame members by the metal deck members 24. Preferred orientation of the ribs 26 facilitates safety in the event that miners are required to walk over the top of the arch as, for example, in using the area as a means to escape the mine in an emergency.

In installations employing three or more arches, a single metal deck member may span three or more arches rather than two as is shown in Fig. 2. A continuous span over three arches serves to provide increased balancing of internal bending moments and increased load capacity for a given deck member as compared with a simple span between two arches. For convenience of handling, a single piece of deck may be about 3 feet (1 m) wide and 12 feet (4 m) long.

In general, the interior of the mine arch construction will have a substantially uniform cross-section throughout its length.

Fig. 3 illustrates a fragmentary section of a completed mine arch unit, in which the structural steel frame members 9 are covered by the metal deck members 24 and wherein the enclosed inside region 10 of the construction defines a first passageway for the transport of air. In order to seal the region 36 between the arch and the overlying roof 32, cinder block walls 34 are provided at closed ends or adjacent opposed ends of the arch so as to define the lateral extent of the passageway which overpasses the arch.

As shown in Fig. 4, which illustrates the lower frame segment 2 in greater detail, an externally threaded stud member 40 projects outwardly from the segment 2. As will be described in detail below, the stud member 40 is used to secure metal deck members 24 to the frame 9.

As shown in Figs. 5 and 6, the intermediate beam segment 4 is provided with a pair of outwardly projecting, externally threaded studs 40 adjacent the ends thereof, and, as shown in Fig. 7, the intermediate beam segments 6 also have a plurality of externally threaded, outwardly projecting studs 40. The threads of the studs 40, while preferably being continuous, may be discontinuous thread segments or the equivalent so long as a locking action is achieved. It will be appreciated that the positioning of the studs 40 will be such as to correspond to the desired points of securement of the deck members 24.

In general, it is preferred to provide preformed openings in the metal deck members to receive the studs 40. The ends of each beam segment 6 are tapered to correspond with an adjacent segment to facilitate effective fastening, for example, by nut and bolts (not shown), of the end flanges.

Figs. 8 and 9 illustrate a portion of an upper segment 8. As shown, each segment 8 has an end flange 42 that has a plurality of openings 44 adapted to receive fasteners passing through a like flange of the adjacent segment 8.

Fig. 10, illustrates a portion of a pair of metal deck members 50, 52. The deck member 50 has a valley 54 and a rib 56. Similarly, deck member 52 has a valley 58 and a rib 60.

As best seen in Figs. 10, 1 5 and 1 6 the metal deck member 50 has a male flange 62 that projects upwardly and terminates in a generally outwardly and downwardly projecting curl portion 64 (Fig. 15). The metal deck member 52 has a female flange 66 which projects upwardly and terminates in a downwardly projecting portion 68 which with the flange 66 defines a generally downwardly open channel 70. It will be appreciated that each metal deck member thus formed will have one lateral edge with a male flange and the other lateral edge with a female flange.

Both flanges are preferably substantially continuous and substantially coextensive with the length of the deck member. In order to join two deck members together, the male flange 62 of one metal deck member is inserted into the channel 70 of the adjacent female deck member. If desired, the join between the two deck members may be enhanced by employ ing a crimping tool at various locations along the length of the joint to crimp the female flange 68 so as to provide for more intimate engagement with the male flange 62.

As seen in Fig. 16, in order to improve the leakproof characteristic of the arch beam construction, particularly in respect of air flow, it is preferred to provide a suitable gasket material 72 within the channel 70, the gasket material 72 being compressed on engagement with the curl portion 64 of the male flange 62 to provide an effective seal between adjacent deck members. Among the preferred materials for use as gasket material 72 are resinous polymer foams and neoprene. A suitable neoprene material is that sold by Toyad Corporation of Latrobe, Pennsylvania under the trade name "RP neoprene, LS-200 Low Smoke." To further enhance the air sealing properties of the mine arch construction, metal deck members having integrally formed surface irregularities such as integrally formed ribs, dimples and the like in the rib walls may be employed.These irregularities serve to facilitate mechanical retention of any sealant coatings that may be applied to the deck member surfaces. This in turn facilitates improved air sealing at zones of overlap between deck member and zones of deck member contact with the support frames.

Referring again to Fig. 10, the metal deck members 50, 52 preferably have a series of preformed openings 80 so positioned as to correspond with the positions of externally threaded stud members 40 which are secured to the beam elements defining frame mem bers 9. In the embodiment illustrated, a pair of stud members 40 project through a pair of openings 80 within valleys 54, 58 on opposite sides of the joint connecting the two metal deck members 50, 54. When a deck member has been positioned over a metal stud 40, as is shown in valley 58 (Fig. 10), a nut member, which may take the form of a conventional internally threaded nut or, prefer abiy, a unique form of nut 84 (that will be described in more detail below) so as to provide for intimate securement of the metal deck member to a frame member.

Referring now to Figs. 11 through 14 a preferred nut 84, which may be made of sheet metal, will be described. The nut 84 has a generally rectangular periphery but with a downwardly concave profile. The nut 84 has a main body portion 78 with a central opening 86. A pair of upwardly and inwardly projecting cantilevered tabs 88, 90 each terminate in generally V-shaped notches 92, 94 which co-operate with portions of the body member 78 to define the central opening 76.

When such nuts are used to secure metal deck members to studs 40, engagement of the nut with the free end of the stud 40 will cause resilient upward and outward deformation of tabs 88, 90 thereby permitting the nut 84 to move downward to the desired locking position. At that point the tabs 88, 90 will, due to the resiliency of the material move downwardly and inwardly so as to permit the notches 92, 94 to engage the thread, thereby resisting separation of the deck member from the beam. It will be appreciated, however, that the nut 84 cannot be removed by a simple sliding movement in the reverse direction. Removal of the nut 84 can be effected only by unthreading through relative rotational movement established between the nut 84 and the stud 40.

In order to disassemble the mine arch construction of the present invention the cycle of operation discussed above need merely be reversed.

The present invention has been found to provide an improved, prefabricated mine arch construction that can be adapted for use as an overcast and for other mine purposes.

The present invention has also been found to provide an arch construction which is economical to manufacture, install and disassemble for reuse.

The invention has further been found to provide such an arch construction which has lightweight components and is adapted to maintain effective air seals throughout extended periods of use.

Such a mine arch in accordance with the invention has been found to be adaptable to deflect with movement of adjacent strata without cracking or otherwise losing its structural integrity.

The invention has been found to provide such a construction which establishes air sealing through a combination of improved fastening means, joint construction and specifically positioned gasket means, and to simplify installation of overcasts and the like by minimizing the number of individual parts which mus' be handled during assembly or disassembly.

The invention has been found to provide a mine arch construction which, as a result of the preferred orientation of the metal deck ribs, may be walked on with improved safety by men passing thereover in evacuating a mine.

Thus, it has been found that an embodiment of the present invention provides a prefabricated load bearing skeleton-skin mine arch construction which is economical to manufacture and use, light weight, minimizes the handling of small parts, is capable of ready disassembly and provides the benefit of the unique fastener systems, gasket arrangements and panel joining techniques.

While a preferred form of male4emale metal deck member joint has been disclosed it will be appreciated that a wide variety of lateral joints with or without interposed sealant may be employed, if desired.

Claims (23)

1. A mine arch construction comprising: a first load-bearing generally arch-shaped frame member and a second load-bearing generally arch-shaped frame member spaced from and disposed generally parallel to said first frame member, each said frame member having a number of outwardly projecting, externally threaded stud members secured thereto; a plurality af deck members, having alternating ribs and valleys, secured to said frame members to define an open-ended enclosure, said threaded stud members passing through said deck members, and having retainer means secured to said stud means to retain said decks members in place.

2. A mine arch construction according to claim 1, wherein said retainer means comprise nut means that are adapted to be removed from said stud means by unthreading.

3. A mine arch construction according to claim 1 or claim 2, wherein said mine arch construction is adapted to be disposed in a mine passageway intersection to form a mine overcast.

4. A mine arch construction according to claim 3, wherein a first ventilation passageway is defined by said mine arch construction in cooperation with the underlying floor of the mine passageway, and a pair of spaced wall means are disposed between said metal deck members and the passageway walls and roof to define a second ventilation passage oriented generally transversely with respect to said first ventilation passageway.

5. A mine arch construction according to any one of claims 1 to 4, wherein said retainer means is a sheet-like nut member having resiliently deformable portions that permit securement of the retainer means to said stud members by relative sliding movement thereover but resist removal by relative sliding movement.

6. A mine arch construction according to claim 5, wherein said nut member engages with the thread of said stud member when in a secured position and is adapted for removal therefrom by unthreading.

7. A mine arch construction according to claim 5 or claim 6, wherein said nut member is formed from sheet metal.

8. A mine arch construction according to any one of claims 5, 6 or 7, wherein said nut member has a generally downwardly concave shape, and a pair of opposed generally upwardly and inwardly projecting cantilevered tabs co-operate with a pair of opposed lateral walls to define a central opening.

9. A mine arch construction according to claim 8, wherein said cantilevered tabs each have a generally V-shaped notch adjacent said central opening.

10. A mine arch construction according to any one of claims 1 to 9, wherein said deck members are metal, lateral edges of adjacent said deck members having mating male and female flanges in engagement to establish a joint therebetween, and said stud passes through a preformed opening in a valley portion of each of said adjacent deck members generally adjacent to said male-female joint.

11. A mine arch construction according to claim 10, wherein said male flange is generally upwardly projecting, and said female flange is generally upwardly projecting but terminates in a downwardly extending reentrant portion to define a channel, that is adapted to receive said male flange.

1 2. A mine arch construction according to claim 11, wherein said male and female flanges are substantially coextensive with said deck member.

1 3. A mine arch construction according to claim 1 2, wherein said deck ribs further comprise a plurality of integrally formed surface irregularities.

14. A mine arch construction according to claim 13, wherein a coating of sealant material is secured to said metal deck over said irregularities.

1 5. A mine arch construction according to any one of claims 1 to 14, wherein gasket means is disposed between adjacent deck members.

1 6. A mine arch construction according to claim 15, wherein said gasket means includes a resinous foam material.

1 7. A mine arch construction according to any one of claims 1 to 16, wherein said deck ribs are oriented generally horizontally.

1 8. A mine arch construction according to any one of claims 10 to 17, wherein said joints have said female channels crimped into intimate mechanical engagement with said male flange at a plurality of locations.

1 9. A mine arch construction according to any one of claims 1 to 18, further comprising at least one additional frame member spaced from and disposed generally parallel to said second frame member.

20. A mine arch construction according to any one of claims 1 to 19, further comprising strut means connecting adjacent said frame members.

21. A mine arch construction according to claim 20, wherein said strut means connect upper portions of said frame members.

22. A mine arch construction substantially as herein described with reference to, and as shown in, the accompanying drawings.

23. Any novel feature and any novel combination of features disclosed herein.