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Patent Searching and Data


Title:
FACEPLATE MADE OF COMPOSITE MATERIAL
Document Type and Number:
WIPO Patent Application WO/2019/104359
Kind Code:
A1
Abstract:
The invention provides a washer (10, 10A) made of a composite material which has a plate-like body (12) with a first surface (14) and a second surface (16), a perimeter edge, a central aperture (20) through the body and a yielding zone (34), circumscribing the aperture and a metal load distributing ring (30) engageable with the first surface to cover at least part of the yielding zone.

Inventors:
ABREU, Rual (109 Adcock Ingram AvenueAeroton, Pty1451 Johannesburg, 1451, ZA)
Application Number:
ZA2018/050056
Publication Date:
May 31, 2019
Filing Date:
November 02, 2018
Export Citation:
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Assignee:
NCM INNOVATIONS (PTY) LTD (109 Adcock Ingram Avenue, Aeroton Johannesburg, 1451 Johannesburg, 1451, ZA)
International Classes:
E21D21/00
Foreign References:
DE19525610A11996-01-18
EP0861969A11998-09-02
EP1933005A12008-06-18
AU1636970A1971-12-23
DE102010010182A12011-10-06
GB2311578A1997-10-01
US4371293A1983-02-01
Other References:
None
Attorney, Agent or Firm:
TABERER ATTORNEYS et al. (14 Kendal Mews, Diep River Cape Town, 7800 Cape Town, 7800, ZA)
Download PDF:
Claims:
CLAIMS

1 . A washer made of a composite material which has a plate-like body with a first surface and a second surface, a perimeter edge, a central aperture through the body and a yielding zone, circumscribing the aperture and a metal load distributing ring engageable with the first surface to cover at least part of the yielding zone.

2. A washer according to claim 1 wherein the composite material is a thermo plastic material.

3. A washer according to claim 2 wherein the thermo-plastic material is polypropylene, polyamide, HDPE, LDPE or PEEK (polyether ether ketone).

4. A washer according to claim 1 wherein the composite material is an injectable resin.

5. A washer according to claim 4 wherein the injectable resin is fibreglass.

6. A washer according to any one of claims 1 to 5 wherein the body includes a tensioning-barrel engaging formation which rises which from the first surface and which is concentric with the aperture and which formation has a cylindrical wall and a recessed seat between the wall and the aperture.

7. A washer according to claim 6 wherein the metal load distributing ring locates within the cylindrical wall, on the recessed seat.

8. A washer according to claims 1 to 7 wherein the body includes a plurality of rigidifying ribs on the first surface that outwardly extend from the cylindrical wall in a radially spaced pattern.

9. A washer according to claims 1 to 8 wherein the yielding zone is formed in at least one surface.

10. A washer according to claims 1 to 9 wherein the yielding zone includes a plurality of yielding formations which are radially spaced from one another.

1 1 . A washer according to claim 10 wherein each yielding formation is a hole formed through the body or a recess or pocket formed within a surface of the body.

Description:
FACEPLATE MADE OF A COMPOSITE MATERIAL

FIELD OF THE INVENTION

[0001 ] The invention relates to a faceplate made of a composite material and used in a rock anchor installation. [0002] Hereinafter, the terms“washer” and“faceplate” are used interchangeably.

[0003] A faceplate, typically, is made of a metal material. This poses a potential problem. In certain mechanised mining operations, a subsequent pass is made through the excavation to recover remaining ore material. This ore material is penetrated with mine support infrastructure such as rock bolt assemblies. When excavated, these rock bolt assemblies will mix with the ore material. These assemblies, and especially the angular faceplates of these assemblies, can damage the tyres of the mechanised mine vehicles.

[0004] To avoid this problem, faceplates can be made of a composite material.

[0005] However, a faceplate of a composite material (“composite faceplate”) has its own problems. It has been found by the applicant, during testing, that a perimeter zone about an aperture of the faceplate is a zone of relative weakness due to the concentration of forces within this zone imposed by a loaded rock-bolt when installed. This load concentrated on the perimeter zone, can cause the washer to fracture and break. [0006] This problem is amplified when the washer abuts an uneven rock wall surface, or the rock hole is not perpendicular to the rock face remiting in an oblique installation. In both instances, the faceplate experiences radially uneven stress.

[0007] The invention at least partially solves the abovementioned problems.

SUMMARY OF THE INVENTION

[0008] The invention provides a washer made of a composite material which has a plate-like body with a first surface and a second surface, a perimeter edge, a central aperture through the body and a yielding zone, circumscribing the aperture and a metal load distributing ring engageable with the first surface to cover at least part of the yielding zone.

[0009] The plate-like body may be any suitable shape, for example square, circular, avoid or rectangular.

[0010] The composite material may be any suitable thermo-plastic material such as, for example, polypropylene, polyamide, HDPE, LDPE, PEEK (polyether ether ketone) or the like. The material is HDPE or polypropylene.

[0011 ] Alternatively, the composite material may be an injectable resin such as, for example, fibreglass. [0012] The body includes a tensioning-barrel engaging formation which rises which from the first surface and which is concentric with the aperture. The formation has a cylindrical wall and a recessed seat between the wall and the aperture.

[0013] The metal load distributing ring may locate within the cylindrical wall, on the recessed seat.

[0014] The body may have a plurality of rigidifying ribs on the first surface that outwardly extend from the cylindrical wall in a radially spaced pattern.

[0015] The yielding zone may be formed in at least one surface.

[0016] The yielding zone may include a plurality of yielding formations which are radially spaced from one another.

[0017] Each yielding formation may be a hole formed through the body or a recess or pocket formed within a surface of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 illustrates a view in perspective of a washer in accordance with a first embodiment of the invention;

Figure 2 is a plan view of the washer of Figure 1 ; Figure 3 is an under-plan view of the washer of Figure 2;

Figure 4 is a plan view of a washer in accordance with a second embodiment of the invention with a yielding zone formed with a plurality of yielding formations;

Figure 5 is a sectioned view, through line 5-5 of Figure 4; and Figure 6 diagrammatically illustrates a rock bolt installation which includes a washer in accordance with a second embodiment of the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0019] The Figures illustrate two embodiments of a composite washer, respectively 10 and 10A, in accordance with the invention. [0020] The washer (10, 10A) has a plate-like body 12, made of a composite material.

[0021 ] The composite material can be any suitable composite material that can form the body by injection moulding. This material can be any type of injectable resin or plastics material. Alternatively, the material can be a fibre reinforced thermo-plastic from which the body can be formed through pressing or stamping. [0022] In these examples, the body 12 is square, having a first or outer facing surface

14 and a second, or rock wall facing, surface 16. Four edges, respectively designated 18A, 18B, 18C and 18D, delimit the border of the surfaces. An aperture 20 is centrally formed through the body. The aperture 20 is sized to receive a rock anchor in use (see Figure 6). [0023] The body has a tensioning-barrel engaging formation 22 which rises from the first surface 14 and which includes a cylindrical wall 24, which circumscribes the aperture, and a recessed seat 26 between the cylindrical wall and the aperture 20. The recessed seat is stepped below a rim 28 of the wall. This is best illustrated in Figure 1 . [0024] The washer (10, 10A) includes a rigid steel load distributing ring 30. The ring is complementary to the inner dimensions of the cylindrical wall 24 to engage the recessed seat 26.

[0025] In the first embodiment, illustrated in Figure 2, the washer 10 has a yielding zone 34 which circumscribes the aperture, beneath the recessed seat 26, within the cylindrical wall 24. This zone, unlike the yielding zone 34A of the washer of the second embodiment of the invention described below, is not formed with any yielding formations. In this embodiment, the choice of the material is important. This material, preferably, is an FIDPE or polypropylene, chosen for being highly ductile.

[0026] In a second embodiment of the invention, illustrated in Figures 3 to 5, the washer 10A includes a plurality of yielding formations, within the yielding zone 34A, to aid in the collapse of the zone as will be described below. The yielding formations are, in this particular embodiment, a circular array of rectangular pockets or holes. The pockets or holes are respectively designated 32A, 32B .32N are formed either in or through the body, within the yielding zone. [0027] To rigidity the plate-like body 12 of the washer (10, 10A), and to prevent the body from deforming, by bending in directions transverse to the plane of the body due to forces imposed upon the body in use, the body includes a plurality of radiating buttress formations 36. Each buttress formation extends from an outer side 38 of the cylindrical wall 24. The ribs radiate from the cylindrical wall, evenly radially spaced from one another. [0028] Some of the buttress formations (designated 36A, 36B, 36C and 36D) extend to a corner 40 of the body. On laterally outer parts of each of these specific formations, an attachment member 42 is formed to which, for example, a net attachment hook can be engaged.

[0029] The washer (10, 10A) is part of a rock anchor installation, as is illustrated in Figure 5. The installation includes a cable anchor 44 which passes through the aperture 20 in the washer. The cable anchor is tensioned in preload and keep in preload, in a rock hole 46, by a tensioning assembly such as a barrel and wedge assembly 48. A conical leading end 58 of a barrel 52 of the assembly abuts the load distributing ring 30. The tension in the cable anchor pulls the washer in load supportive contact with a hanging wall 54 of an excavation.

[0030] As is illustrated in Figure 5, the cable anchor 44 is installed obliquely to the plane of the washer 10A. This often occurs in practice, for the reasons described above, causing the barrel to impart radially uneven stress on a perimeter zone about the aperture. In this illustrated example, more force is applied, by the obliquely aligned barrel, to a right side of the washer. This unevenly applied load is graphically illustrated with bidirectional arrows, the respective lengths of which illustrate magnitude. [0031 ] With either embodiment, the rigid steel load distributing ring 30 acts to absorb and circumferentially distribute these asymmetrically applied forces, which are caused by the oblique orientation and the shape of the spherical seat, over the yielding zone (34, 34A). With better load distribution, point loading, and the creation of high radial stresses which would radiate from the aperture, are minimised. This mitigates against the washer body 12 splitting or cracking.

[0032] Another feature of the washer (10, 10A), that lessens the risk of splitting or cracking, is that the body 12 is adapted to absorb uneven compressive load within the yielding zone 34. In the case of the washer 10, the ductile material of manufacture allows this yield.

[0033] In the case of washer 10A, there is the additional structural feature in the circular array of pockets or holes 32 which provide additional yield to the compressive load by collapsing or partially collapsing. This collapse is of greater extent in an arc about the side of the aperture experiencing greater load, i.e. the right side in this example. Figure 5 illustrates this, showing hole 32H in a greater state of collapse than the diametrically opposed hole 32B.

[0034] The risk of damage to washer 10, associated with this uneven application of load, therefore is mitigated by the load distributing ring 34, and the material of manufacture of the structural features within the yielding zone.