AU2311401A - A screen module - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: c Name of Applicant: Lettela Pty Limited Actual Inventor(s): Raymond Maxwell Woodgate Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: A SCREEN MODULE Our Ref: 637521 POF Code: 95/17556 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 2 A SCREEN MODULE The present invention relates generally to screening, separating or grading of particulate or granular material, and in particular to a screen module for support on a screen frame in an ore screening apparatus. Apparatus of this type is currently used in screening, separating and grading mined ores and it will be convenient to hereinafter describe the invention to this exemplary application. It is to be understood, however, that the invention is not limited to this particular application.

Screening apparatus is commonly used in the grading or separation of ore and includes a sub-frame on which a screen system is mounted. One such system provides a plurality of screen panels, each comprising an array of screen modules forming a screening surface and being mounted on a screen frame. The screen frame is secured to the sub-frame along its opposite edge regions, typically using a clamp assembly which places the screen frame in tension. The sub-frame further includes a plurality of support members which :extend beneath the screen frame and are operable to apply an upward force to the screen frame so as to produce a camber over the screening surface.

Apertures are provided in the screen modules for ore screening and separation. The aperture size may vary between the panels and typically 20 increase along the length of the apparatus from a feed to a discharge end so that ore of different sizes may be separated. Alternatively, the aperture size of the panels may be the same throughout the apparatus such that it is operable to only screen one size of material.

Due to the abrasive nature of the ore, individual screen modules and panels require regular removal and replacement. To facilitate replacement and to minimise downtime typically the apparatus is arranged such that the individual modules can be removed whilst the screen frame remains mounted on the sub-frame.

An aim of the present invention is to provide a screen module which can be readily mounted into and removed from a support system of an ore screening apparatus.

According to the present invention, there is provided a screen module for support on a screen frame in an ore screening apparatus, the screen frame W:tateSPECfDivof726837.doc 3 having a plurality of spaced apart elongate frame members, the screen module including: an upper screening surface; ore screening apertures extending through the module and opening onto the screening surface; at least two connection regions; and, an elongate connection recess in each connection region for receiving a respective elongate frame member therealong to releasably connect the screen module to the screen frame for support thereon.

In at least one form, the connection regions are elongate, and the connection recesses extend along the respective connection regions. The connection regions are preferably provided one each at opposite edges of the module. Moreover, preferably at least one further connection region is provided •intermediate the connection regions at the opposite edges. One further connection region may be located midway between the connection regions at the opposite edges.

In one form, the module is rectangular in plan shape. The connection S 15 regions extend transverse to the longitudinal extent of the module, in this form.

In one form, the frame members are frame bars. The connection recesses are connection slots shaped and sized to engagingly receive the o frame bars therein, in this form.

Preferably, the connection slots are shaped and sized to snap 20 engagingly receive the frame bars therein. The connection slots may be key 0. hole shaped in transverse cross section.

In one form, the module has a lower supporting surface spaced from the upper screening surface. The connection slots extend along and open onto the supporting surface, in this form.

Preferably, the connection slots extend entirely along the connection regions and open onto opposite sides of the module. The connection slots may extend parallel with one another.

The screen module may be cast or moulded from plastics material, such as polyurethane. The frame bars are typically composed of metal and, in a preferred form, are rods of constant cross-sectional shape, such as circular, but may be square or hexagonal.

It will be convenient to hereinafter describe an embodiment of the invention in greater detail with reference to the accompanying drawings. The W:*kateSPEClivo f726837.doc 4 particularity of these drawings in the related description is not to be understood as superseding the generality of the preceding broad description of the invention.

In the drawings: Fig. 1 is a plan view of a screen panel incorporating screen modules according to a preferred embodiment of the present invention; Fig. 2 is a plan view of the screen frame of the panel of Fig. 1; Figs. 3 and 4 are plan and end views respectively of one screen module from the panel of Fig. 1; Fig. 5 is a partial transverse cross-sectional side view of a support ~s

I

System incorporating the screen panel of Fig. 1 and installed in a screening capparatus; Figs. 6 and 7 are plan and side elevation views respectively of a support member cover of the support system of Fig. 5; and Fig. 8 a cross-sectional view of the cover of Fig. 6 to an enlarged scale along section lines A-A.

Referring firstly to Figs. 1 to 4, there is shown a screen panel 11 which forms part of a screening apparatus 10 (Fig. 5) for use in the screening and separating of ore. The panel 11 is formed from a plurality of screen modules 12 20 mounted in a regular array on a screen frame 13. As best illustrated in Figs. 3 and 4, each screen module 12 has a rectangular plan shape with a pair of opposite side edge regions 14 and a pair of opposite upstream and downstream end edge regions 15. Each screen module 12 has an upper screening surface 16 for receiving ore or other material to be screened and a lower surface 17 which is in facing relationship with the screen frame 13.

Screening apertures 18 extend through the screen module 12 between the upper and lower surfaces 16, 17 to provide for ore screening and separation.

The modules 12 are constructed for releasable mounting onto the screen frame 13 in abutting side-to-side and end-to-end relationship so that their array forms a screening surface 19 of the apparatus As shown in Fig. 2, the screen frame 13 is rectangular and incorporates opposite side edge regions 20 which are interconnected by a plurality of frame members 21. The side edge regions 20 are provided by spaced apart side W:a*teSPECflDivoI726837.doc frame members 22. Each member 22 is of generally L-shaped cross section with a downwardly facing support surface 23 and an inwardly facing abutment surface 24 (see Fig. The frame members 21 in the illustrated form comprise metal rods of constant cross section. Typically the rods are of circular cross section although it is to be appreciated that any other suitable shaped cross section could be used such as hexagonal, square or the like.

The frame members 21 are captured in appropriate shaped slots formed in the side frame members 22 of the screen frame 13. In the illustrated form, a total of six members of approximately 10mm diameter are provided in each frame 13. However, the number and size of the members 21 may vary depending on the application requirements.

The screen frame 13 further includes a central bolt down region S•located intermediate and parallel to the opposite side edge regions 20. The bolt down region 25 is formed from two pairs of fixing plates 26 and 27 with respective pairs being disposed on opposite sides of the frame members 21.

The fixing plates of each pair are in spaced relationship to provide a central recess 28 adapted to receive a fastening assembly as will be described in more detail later.

20 As mentioned above, the screen modules 12 are releasably connected to the screen frame 13. In the illustrated form, the modules 12 incorporate a plurality of connection slots 29 which extend between the opposite side edge regions 14 and which are shaped to inter-engage with the frame members 21 of the screen frame 13. In the illustrated form, the slots 29 are shaped as keyholes to provide a snap-fit engagement with respective frame members 21.

Each module 12 includes three slots 29, one being adjacent a respective upstream and downstream edge region 15 and the other being in a mid region of the module 12. With this arrangement, the modules 12 are arranged to be connected in place on the screen frame 13 under manual pressure and may be released from the frame members 21 by levering off using a suitable tool, such as a screwdriver.

Referring to Fig. 5 of the drawings, the screening apparatus 10 includes a sub-frame 30 on which the screen panel 11 is mounted. The sub-frame W:MateSPECl.Divof726837.doe includes spaced apart side mounting regions 31, central mounting region 32 and intermediate support regions 33. The apparatus 10 is generally symmetrical about the centre line of the central mounting region 32 and for ease of illustration, only one of the side regions 31 and support regions 33 are shown in Fig. Each side mounting region 31 incorporates a side plate 34 extending along the screening surface 19 of the apparatus 10, parallel with a path P along which ore moves during screening by the apparatus 10. The side mounting region 31 also has an inwardly extending support member 35 mounted to the inner face of the side plate 34. The support member 35 is formed as an angled section which is typically mounted to the inner face of the side plate 34 with fasteners or by welding. The support member 35 includes an upwardly facing bearing surface 36 on which bears support surface 23 of corresponding side S•edge region 20 of the screen frame 13. It should be appreciated that that the sub-frame 30 may support one screen panel 11 or alternatively, as is more typical, a plurality of screen panels 11 arranged in abutting relationship along the ore screening path P of the apparatus The side mounting region 31 further includes a clamp assembly 37 for mounting the screen frame 13 in tension across the ore screening path P. The clamp assembly 37 includes a clip 38 which is movably mounted relative to the side plate 34. An upper end 39 of the clip 38 is configured so to be received under a location block 40 secured to the side plate 34 whereas a lower end 41 of the clip 38 abuts the inwardly facing surface 24 of the screen frame 13.

The clamp assembly 37 further includes a tensioning device 42 which is has a nut and bolt assembly 43 interconnecting the clip 38 and the side plate 34. In the illustrated form, the bolt 44 of the assembly 43 has a head 45 which is in abutting relationship with the clip 38. The shaft 46 of the bolt 44 extends through an aperture 47 in the side plate 34. A nut 48 is threadingly engaged with the bolt 44 and a tapered bush or washer 49 is located between the nut 48 and an outer face 50 of the side plate 34. Typically the bush 49 is formed of a rigid material such as metal, for example, steel. It will be appreciated that, on tightening the nut 48 the clip 38 will be drawn toward the side plate so that the lower end 41 applies a tensioning force through the side edge region 20 to the W:MkateSPECl'DWoU726837.doc screen frame 13. In this way the frame members 21 are placed in longitudinal tension, with the screen frame 13 being placed in tension across the ore screening path P.

The central mounting region 32 of the sub-frame 30 is cooperable with the bolt down region 25 of the screen frame 13 to achieve mounting of the screen frame 13 to the underlying sub-frame 30 at that region 25. The mounting region 32 has a support beam 51. The beam 51 is formed as an angled section and provides an upwardly facing support surface 52. The support surface 52 is engaged by the downwardly bearing fixing plates 27 in the bolt down region A fastening assembly 53 is included in the mounting region 32, which engages the upper fixing plates 26 in the region 25 so as to clamp the screen frame 13 into engagement with the support beam 51. In the illustrated S"arrangement, the fastening assembly 53 includes a nut and bolt assembly with S 15 the shaft of the bolt 54 passing through the central recess 28 formed between the pairs of fixing plates 26 and 27.

An elongate cover strip 55 is removably located over the fastening assembly 53. That strip 55 is configured for fixing engagement about upper fixing plates 26, and overlies adjacent side edge regions 14 of the screen 20 modules 12. The cover strip 55 acts to prevent the ingress of contaminant material such as ore fines and the like into the region of the central mounting region 32.

The intermediate support regions 33, only one of which is shown, extend the length of the ore screening path P of the apparatus 10 at positions intermediate each of the side mounting regions 31 and the central mounting region 32 and operate to apply an upward biasing force against the screen frame 13 of the screening panel 11. This upward force is designed to produce a camber across respective sections of the screening surface 19 of the apparatus 10 to encourage the spread of ore across the screening surface.

The effect of fastening the screen panels 11 at the central mounting region 32 is to produce two cambers across the screening surface 19 between the opposite side mounting regions 31 of the sub-frame W: kateNSPEC~Divof726837.doc 8 In the form shown, each support region 33 has an elongate support member 56 which extends along the ore screening path P of the apparatus and a cover 57 which is seated along an upper end 58 of the support member 56. The cover 57 is configured to engage the transversely extending (relative to the ore screening path P) frame members 21 of the screen frame 13 so as to impart the camber biasing force thereto. Furthermore, the cover 57 includes locating means 59 which engage the frame members 21 so that they are maintained in their correct position.

Figs. 6 to 8 of the drawings illustrate the cover 57 in detail. The cover 57 is elongate and made from a plastics material such as polyurethane or the like, reinforced by a metal strip The locating means 59 is provided at upper region 61 of the cover 57 Sand includes a series of transverse grooves 62. The grooves 62 are shaped S"and sized to inter-engage with respective ones of the frame members 21 of the screen frame 13. In particular, the grooves 62 are dimensioned so that the frame members 21 will sit into them, with the opposing walls 63 of the grooves resisting lateral movement of the frame members 21 along the cover 57 and support member 56. It should be appreciated that the locating means could take other forms, such as clips or projections or the like Furthermore, whilst in the illustrated form the frame members 21 are configured to only sit in the grooves, the locating means could be arranged so that the frame members 21 are positively retained in position through a frictional, interference, or snap fit engagement.

In the illustrated form, a lower end 64 of the cover 57 incorporates a pair of downwardly extending legs 65 which define therebetween a longitudinally extending recess 66. The recess 66 receives the upper end 58 of the support member 56 so as to enable the cover 57 to seat thereon. It will be appreciated that other alternative methods of locating the cover 57 on the support member 56 may be used.

With the support member 56 in position engaging the frame members 21, the upper end 61 of the cover 57 is disposed at, or adjacent, to the top of the frame members 21. To avoid interference between the modules 12 which have their lower surface 17 disposed below the frame W:kateSPECI DiYof726837.doc 9 members 21, slots are formed in the modules 12 to accommodate the upwardly extending support members 56 and in particular the covers 57. These slots (not shown) may be pre-formed or can be formed on site by cutting out sections of the modules 12 using a knife or the like.

By having the support member 56 arranged to restrain the frame members 21, additional rigidity is provided to the screen frame 13. In particular, it enables the frame members 21 to be restrained from buckling both in a generally vertical plane by bearing against the upper end 61 of the support cover 57, and in a horizontal plane, by virtue of the rods engaging the opposing walls 63 of the grooves 62. This assists in resisting screen frame distortion. As i a result, it enables the frame members 21 in the screen frame 13 to have a larger free span. This in turn enables the screen frame to be of lighter weight *construction as it enables a reduction in the number and/or size of the frame members 21 in the screen frame 13.

Finally, will be understood that various alterations, modifications and/or additions may be introduced into construction and arrangement of the parts previously described without departing from the spirit or ambit of the invention.

W:kate\SPECI\Dvof726837.doc

Claims (13)

1. A screen module for support on a screen frame in an ore screening apparatus, the screen frame having a plurality of spaced apart elongate frame members, the screen module including: an upper screening surface; ore screening apertures extending through the module and opening onto the screening surface; at least two connection regions; and, an elongate connection recess in each connection region for receiving a respective elongate frame member therealong to releasably connect the screen module to the screen frame for support thereon.

2. A screen module as claimed in claim 1, wherein the connection regions are elongate, and the connection recesses extend along the respective connection regions.

3. A screen module as claimed in claim 1 or 2, wherein the connection S•regions are provided one each at opposite edges of the module.

4. A screen module as claimed in claim 3, wherein at least one further connection region is provided intermediate the connection regions at the opposite edges.

5. A screen module as claimed in claim 3 or 4, wherein a further connection region is located midway between the connection regions at the opposite edges.

A screen module as claimed in any preceding claim, wherein the module is rectangular in plan shape and the connection regions extend transverse to the longitudinal extent of the module.

7. A screen module as claimed in any preceding claim, wherein the frame members are frame bars, and the connection recesses are connection slots shaped and sized to engagingly receive the frame bars therein.

8. A screen module as claimed in claim 7, wherein the connection slots are shaped and sized to snap engagingly receive the frame bars therein.

9. A screen module as claimed in claim 7 or 8, wherein the connection slots are key hole shaped in transverse cross section. A screen module as claimed in any one of claims 7 to 9, including a lower supporting surface spaced from the upper screening surface, and the connection slots extend along and open onto the supporting surface.

W:WateZSPECDivof726837.doc 11

11. A screen module as claimed in any one of claims 7 to 10, wherein the connection slots extend entirely along the connection regions and open onto opposite sides of the module.

12. A screen module as claimed in any one of claims 7 to 11, wherein the connection slots extend parallel with one another.

13. A screen module for support on a screen frame in an ore screening apparatus, substantially as herein described with reference to the accompanying drawings. DATED: 20 February 2000 PHILLIPS ORMONDE FITZPATRICK Attorneys for: LETTELA PTY. LTD. e* 9* W:\ate\SPEC1lDivof726B37.doc