AU684644B2

AU684644B2 - Bearer plate

Info

Publication number: AU684644B2
Application number: AU27258/95A
Authority: AU
Inventors: John Gowing Lesslie
Original assignee: Ani Corp Ltd
Current assignee: DSI Underground Australia Pty Ltd
Priority date: 1994-08-02
Filing date: 1995-07-28
Publication date: 1997-12-18
Anticipated expiration: 2015-07-28
Also published as: AU2725895A

Description

-1I-

AUSTRALIA

PATENTS ACT 1990 CO0M PL ET E S P EC I F I CAT TO N FOR A STANDARD PATENT O RI GI N AL :::Name of Applicant: Actual Inventor: Address for Service: Invention Title: Details of Associated THE ANI CORPORATION LIMITED, A.C.N. 000 421 358 John Gowing LESSLIE lMaigairt -Street CGPo Box ?Sqs SYDNBY NZ 2000U Sllo)PiEy N.SW Q061 ADDRESS FOR SERVICE

ALTERED

"BEARER PLATE" Provisional Application No: PM7221. dated 2nd August, 1994 The following statement is a full description of this invention, including the best method of performing it known to us:- 2 The present invention relates to a bearer plate for use with rock bolts or friction rock stabilisers and in particular to a bearer plate having an increased compression resistance for a given material thickness.

Bearer plates, also commonly known as face plates or rock plates, are used with various types of rock bolts or friction rock stabilisers, to bind together rock strata to stabilise the rock formation and inhibit its collapse. The bearer plates act to distribute the load applied by the bolt. The bolts and bearer plates in combination have application in mines, rock cuttings, tunnels and any other excavations where stabilisation of the rock strata is required.

Whilst a wide variety of different bearer plates are available, it has previously been necessary to use relatively heavy gauge materials to achieve the load ratings required.

This adds not only to the material cost, but also to the production cost in terms of the cost of tooling and press capacity required to make the plates.

It is an object of the present invention to provide a bearer plate of increased 1 5 compression strength for a given material thickness.

There is disclosed herein a bearer plate for use with a rock bolt, said bearer plate comprising: a plate formed of rigid sheet material, said plate having a first outer peripheral portion having a substantially planar earth engaging surface, and a second inner Si substantially centrally located portion including an aperture therein having an axis extending substantially transverse to the planar extent of the earth engaging surface; [N:\LIBLL]01077:KEH 3 a substantially frusto-conical wall that circumscribes said second portion and extends generally outwardly away therefrom and to the first portion; said wall including a plurality of spaced apart rib formations that extend in a generally radial direction from the aperture and are indented substantially radially inwardly toward the axis of the aperture.

In a preferred embodiment, the wall surface extends generally outwardly away from the first surface and generally radially inwardly toward the axis of the aperture, preferably at a substantially constant predetermined angle and the rib formations are indented substantially radially inwardly towards the axis of the aperture.

Preferably, a bearer plate as claimed in any one of the preceding claims wherein the wall extends from the first surface to define a generally frusto conical surface that terminates at it's edge remote from the first surface to define an annular bearing surface for a i go °e e :o [N:\LIBLL]01077*KEH 4 engagement with a rock bolt or the like.

In a preferred form, the rim of the aperture comprises an inturned portion of said material, said inturned portion defining said annular bearing surface.

In an embodiment the inturned portion terminates in a substantially cylindrical wall portion extending generally normally to the plane of the first surface.

In another embodiment the periphery of said inturned portion is further inturned into abutment with 10 an inner surface of the wall.

In another preferred form, the bearer plate is welded to a butterfly plate which further distributes the load and helps protect against spalling.

Two preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a first embodiment of a bearer plate according to the invention; Figure 2 is a plan view of the bearer plate shown in Figure 1; Figure 3 is a sectional view of a bearer plate along line 3-3 of Figure 2; Figure 4 is an inverted plan view of the bearer plate shown in Figures 1 to 3; Figure 5 is a perspective view of a second embodiment of a bearer plate according to the invention; Figure 6 is a plan view of the bearer plate shown in Figure 5 Figure 7 is a sectional view of a bearer plate along line 7-7 of Figure 6; Figure 8 is an inverted plan view of the bearer plate shown in Figures 5 to 7; Figure 9 is a plan view of a third embodiment of a bearer plate according to the invention incorporating a service loop; Figure 10 is a sectional view of the bearer plate along line 10-10 of Figure 9; 10 Figure 11 is a plan view of a fourth embodiment of a bearer plate according to the invention •incorporating a service loop; Figure 12 is a sectional view of the bearer plate along line 12-12 of Figure 11; Figure 13 is a plan view of a bearer plate according to the first embodiment of the invention welded to a butterfly plate; .*.Figure 14 is a sectional view of the bearer plate along line 14-14 of Figure 13; Figure 15 is a plan view of a bearer plate according to the second embodiment of the invention welded to a butterfly plate; and Figure 16 is a sectional side view of the bearer plate along line 16-16 of Figure Referring to the Figures 1 to 4, there is shown a first embodiment of a bearer plate according to the invention. The bearer plate 1 comprises a plate shown generally at 2 formed of a rigid sheet material. The 6 plate 2 has a first outer peripheral substantially uni-planar earth engaging surface 3 and a second inner substantially centrally located portion 4 in which is formed an aperture 5. The aperture has an axis 6 which extends substantially transverse to the planar extent of the earth engaging surface 3.

The second portion 4 includes a wall 7 that circumscribes the aperture 5 and which extends generally outwardly away from the plane of the first surface.

10 The wall 7 also includes a plurality of spaced apart indented rib formations 8 that extend in a generally radial direction from the aperture 5, the direction of indentation of the ribs into the wall 7 being opposite to the expected direction of deformation of the wall when it is subjected to a compressive load i applied in the direction of the axis of the aperture.

In the preferred form shown, the wall extends from the first surface to define a generally frusto-conical surface that is preferably inclined at an angle of approximately 1100 to 1200 to the plane of the first surface.

The frusto-conical surface terminates at its edge remote the first surface 3 in an annular bearing surface, shown generally at 9, for engagement with a rock bolt or the like. The rim of the aperture comprises an inturned portion 10 which defines the bearing surface 9. In the embodiment shown, the inturned portion 10 is further inturned into abutment 7 with an inner surface of the wall.

In this first embodiment, the plates each have six equi-angularly spaced rib formations 8 which extend from a position adjacent the bearing surface 9, terminating in a run-out portion 11 that extends substantially tangentially with the earth engaging surface 3. The outer peripheral earth-engaging surface 3 also includes six equi-angularly spaced strengthening ribs 17 of generally U-shaped cross-section angularly 10 intermediate adjacent rib formations 8. The ribs 17 "extend radially from the outer periphery of the second portion to the outer periphery of the first surface.

The abutment of the inturned portion 10 with the 'inner surface of wall 7 provides additional advantages to the bearer plate according to the invention over existing plates.

One of these advantages is that the inturned bearer plate wall is stronger than planar walls of similar dimensions and materials.

Another advantage is the bearer plate has no external sharp edges and thus is safer to handle and results in less operator injury than existing plates.

The bearer plate 1 may be made from a low grade steel. The preferred steel grades are: HA250; XF400: and XF500. The plates are currently produced in a -ariety of thicknesses ranging from 2mm to 6mm and move preferably from 3mm to 5mm. Plate sizes currently envisaged include: round plates of 100mm to 200mm 8 diameter; and square plates having an edge length of 120mm to 150mm. Preferred hole sizes are in the range of 18mm to 59mm. The conical boss section is scaled approximately proportionally for each hole size.

In all embodiments shown, the frusto-conical wall 7 extends approximately 20mm from the upper surface of the first surface 3 and converges from an external diameter at the upper surface of the plate of *.approximately 90mm, to define an aperture opening of 10 approximately 45mm diameter.

Figures 5 to 8 show a second embodiment of a bearer plate similar to the first but having a square surface 3 without the strengthening ribs 17. Like numerals are used to denote corresponding features in this second embodiment.

As best shown in Figure 7, in this second embodiment the inturned portion 10 terminates in a o. cylindrical wall portion 21 extending generally normally to the plane of the first surface 3.

Referring to Figures 9, 10 and 11, 12 there is respectively shown third and fourth embodiments of bearer plates according to the invention. The main features are essentially the same as the first and second embodiments and like reference numerals have been used to denote corresponding features.

The main difference in these third and fourth embodiments to those discussed previously is that the overall plate size is larger and includes a service loop 9 12 through which cabling and hoses can be secured to the supported surface. The loop is formed by shearing a slit adjacent the end of the plate and pressing out the edge to form a loop.

In all embodiments, the bearer plate complete with rib formations is produced in a multi-stage progressive die in the manner well-known to those skilled in the art.

Turning to Figures 13, 14 and 15, 16 there is 10 shown two similar preferred applications of the bearer S"plate 1 according to previous embodiments of the invention in which the bearer plate is pre-welded to a butterfly plate 13. The butterfly plate illustrated has O two parallel transversely extending reinforcing ribs 14 joined by two interconnecting ribs 15 that extend transversely to the ribs 14. The bearer plate 1 is welded peripherally at 16. The resulting structure combines the advantages of both elements and further reduces the number of stock items to be handled. The operation of fitting the plates is also made faster as one unit replaces two items that were previously handled separately. Furthermore, operator error resulting in incorrect matching of the parts is substantially eliminated.

The bearer plate according to the invention achieves a higher resistance to compression loading than the majority of currently available prior art plates.

In the embodiments described, the expected mode of 10 deformation of the frusto-conical wall section is to deform radially outwardly away from the axis of the aperture.

The raised frusto-conical section is also of a more vertical shape than most other "domed style" products on the market, which not only gives the bearer plate more resistance to deformation, it increases the flat bearing surface available in the base of the plate. By indenting the vertically extending ribs inwardly toward the axis and increasing the inclination of the wall surface, it has been possible to increase the compression loading by up to the order of The plates have been tested to industry standards and have achieved significantly higher tonnages for materials which are thinner than other plates in the market place. This has resulted in the ability to supply a plate which is more versatile in this application and at a substantially reduced cost to operators.

Although the invention has been described with reference to a specific embodiment, it will be clear to those skilled in the art, that the invention may be embodied in many other forms.

Claims

1. A bearer plate for use with a rock bolt, said bearer plate comprising: a plate formed of rigid sheet material, said plate having a first outer peripheral portion having a substantially planar earth engaging surface, and a second inner substantially centrally located portion including an aperture therein having an axis extending substantially transverse to the planar extent of the earth engaging surface; a substantially frusto-conical wall that circumscribes said second portion and extends generally ortwardly away therefrom and to the first portion; said wall including a plurality of spaced apart rib formations that extend in a generall" radial direction from the aperture and are indented substantially radially inwardly toward the axis of the aperture.

2. A bearer plate as claimed in claim 1 wherein the wall extends generally outwardly away from the first surface and generally radially inwardly toward the axis of the aperture.

3. A bearer plate as claimed in claim 2 wherein said wall extends generally outwardly away from the first surface and generally radially inwardly toward the axis °o 0 *°k *°oo [N:\LIBLL]01077:KEH 0 12 of the aperture at a substantially constant predetermined angle.

4. A bearer plate as claimed in claim 3 wherein said predetermined angle is between approximately 1100 and

1200. A bearer plate as claimed in any one of the preceding claims wherein the rib formations are indented substantially radially inwardly towards the axis of the aperture. 6. A bearer plate as claimed in any one of the preceding claims wherein the wall extends from the first surface to define a generally frusto conical surface that terminates at it's edge remote from the first surface to define an annular bearing surface for engagement with a rock bolt or the like. 7. A bearer plate as claimed in claim 6 wherein th rim of the aperture comprises an inturned portion of said material, said inturned portion defining said annular bearing surface. 8. A bearer plate as claimed in claim 7 wherein said inturned portion terminates in a substantially cylindrical wall portion extending generally normally to the plane of the first surface. 9. A bearer plate as claimed in claim 7 wherein the periphery of said inturned portion is further inturned into abutment with an inner surface of the wall. A bearer plate as claimed in any of the preceding claims wherein said bearer plate includes six 13 equi-angularly spaced said indented rib formations on the wall. 11. A bearer plate as claimed in any one of the pr, ",ding claims wherein "aid first surface includes a plurality of generally U-shaped ss-section strengthening ribs extending radially from the outer periphery of the second portion to the outer periphery of the first surface. 12. A bearer plate as claimed in claim 11 wherein said bearer plate includes six said equi-angularly spaced strengthening ribs. 13. A bearer plate as claimed in claim 11 wherein said strengthening ribs on said first surface are disposed angularly intermediate said six indented rib formations on said- wall. 14. A bearer plate as claimed in any one of the preceding claims wherein said plate includes a service loop to receive cabling, hoses and/or the like. A bearer plate as claimed in claim 14 wherein said service loop extends normally from the first surface at or adjacent the periphery thereof. 16. A bearer plate as claimed in claim 15 wherein said service loop is formed by shearing a slit adjacent the periphery of the plate and pressing the slit normally outwardly from the first surface to form a loop. 17. A bearer plate as claimed in any one of the preceding claims wherein said bearer plate is formed C ee ee* ee \L7 QS7K [N:\LILL]01077:KE[ 14 from steel plates having a thickness between approximately 2mm and 6mm. 18. A bearer plate as claimed in claim 17 wherein said thickness is between approximately 3mm and 19. A bearer plate as claimed in any one of the preceding claims wherein said first surface has a diameter approximately ranging from 100mm to 200mm. A bearer plate as claimed in any one of the claims 1 to 18 wherein said first surface is 10 substantially square shaped and has an edge length approximately ranging from 120mm to 150mm. 21. A bearer plate as claimed in any one of preceding claims wherein said aperture internal diameter is approximately between 18mm and 59mm. 22. A bearer plate as claimed in any one of the preceding claims wherein said bearer plate is formed from any one of the following steel grades: HA250; XF400; or XF500. 23. A bearer plate as claimed in any one of the preceding claims wherein the bearer plate is welded to a butterfly plate. 24. A bearer plate as claimed in claim 23 wherein the periphery of said bearer plate is welded I said butterfly plate. 25. A bearer plate as claimed in claim 23 or 24 wherein said butterfly plate includes two parallel transversely extending reinforcing ribs joined by two interconnecting ribs extending transversely to said reinforcing ribs. 26. A bearer plate substantially as hereinbefore described with refe,-.ence to Figures i to 4; 5 to 8; 9 and 10; 11 and 12; 13 and 14; or 15 and 16. Dated 28 August, 1997 The ANt Corporation Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON a. a a S a. a a a. a a. a a K I 4 JJ [N:\LIBLL]01077.-KtH Abstract A bearer plate for use with a rock bolt or the like, said bearer plate comprising a plate (2) formed of rigid sheet material. The plate has a first outer peripheral substantially uni-planar earth engaging surface and a second inner substantially centrally located portion including an aperture therein. The aperture has an axis extending substantially transverse to the planar extent of the earth engaging surface The second portion including a wall S* 10 that circumscribes the aperture and extends generally outwardly away from the plane of the first surface The wall includes a plurality of spaced apart indented rib formations that each C C extend in a generally radial direction from the o. 15 aperture, The direction of indentation of said ribs into the wall is opposite to the expected direction of deformation of the wall when it is subjected to a compressive load applied in the direction of the axis of the aperture