AU726837B2 - Improved screen support system - Google Patents

Description

P/00/0oII Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT .000 g* 0 0 a..

Invention Title: IMPROVED SCREEN SUPPORT SYSTEM a a the best method of performing it known to me: 1

C:\WINWORD\DELILAH\ANDREWVLETFMS.DOC

-2- IMPROVED SCREEN SUPPORT SYSTEM The present invention relates generally to screening, separating or grading of particulate or granular material and in particular to a support system for screen modules forming part of 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.

10 Screening apparatus is commonly used in the grading or separation of ooooo *0000ore and includes a sub-frame on which a screen system is mounted. One such too.o to.: 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 20 separation. The aperture size may vary between the panels and typically 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.

Due to the operational environment of the screen apparatus, it is important that the screen frame is durable and able to withstand substantial DG C:NWMNWORDXDELILAHXCOMPLETE\SCREEN.DOC -3loading. In particular, the screen frame needs to be strong enough to withstand impact loading such as may occur from the discharge of ore onto the panels or from the weight of workers standing on the frames to access the modules and panels for maintenance. As a consequence, in the past, the subframe, and particularly the screen frame, have incorporated a relatively large number of frame members to withstand these loadings.

An aim of the present invention is to provide a support system for screen modules of an ore screening apparatus which is more effective than previous systems in withstanding its design loadings. In this way, the system is able to incorporate lighter weight and/or fewer frame members to thereby reduce the weight of the overall system and, importantly, reduce the cost of manufacture.

In one aspect, the present invention provides a support system for screen modules of an ore screening apparatus, the system including: a screen frame for holding a plurality of screen modules in an array so as to form a screen panel providing an ore screening surface, the screen frame having a pair of opposite edge regions; and a sub-frame for operatively supporting the screen panel in the apparatus, the screen frame being securable to the subframe at the opposite edge regions, the sub-frame including at least one support member engagable with the screen frame intermediate its edge regions so that a camber is produced over the screening surface between the edge regions, and the support member having locating means for engaging the screen frame in order to maintain that frame in a predetermined position relative to the support member.

In a preferred form, the screen frame includes a plurality of frame members extending between the opposite edge regions and wherein the support member includes a plurality of locating means engagable with respective ones of the frame members.

With the present invention, the or each support member not only assists in applying the camber to the screening surface but also maintains the screen frame in the predetermined position. This improves the ability of the frame members to withstand loading thereon as the support members act as bracing DG C:\WINWORD\DELILAHCOMPLETE\SCREENDOC -4so as to inhibit buckling of the frame members which may otherwise cause distortion of the screen frame.

The screen modules may be cast or moulded from plastics material, such as polyurethane, and preferably are adapted to be releasably connected to the screen frame. In one form, the frame members comprise elongate frame bars or rods. These frame members 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.

In one form, the modules include connection recesses which are configured to engagingly receive with the frame members therein to releasably secure the modules to the screen frame. In one form, the recesses are in the form of keyhole slots which are shaped and sized to inter-engage with the rod form frame members in a snap-fit arrangement.

In one form, the locating means for the screen frame members includes locating slots or grooves into which the frame members are received. In one form, the support member is elongate and the locating slots or grooves extend transverse to a longitudinal axis of the support member. In this arrangement, the locating means tends to hold members and support them against lateral 0 buckling or other distortion.

20 In one form, the locating means is integrally formed with the support member which is typically of metal construction. However, in a preferred form, the locating means is included in a cover mounted on the support member.

One advantage of this arrangement is that it simplifies conversion of existing screen apparatus to operate in accordance with the present invention.

Preferably, the cover is cast or moulded from a plastics material such as polyurethane, and may be internally reinforced by one or more metal elements, such as steel strips. It should be appreciated that other alternative materials and methods of production may be equally applicable.

Preferably the locating means are integrally formed in an upper region of the cover. Furthermore, the cover may be mounted on the support member through any suitable arrangement. In one form, the cover includes spaced DG C:\WINWORD\DELtLAH\COMPLETE\SCREEN.DOC slots which are adapted to receive fastening means such as bolts to secure the cover to the support member. However, in a preferred form, the cover includes a pair of downwardly extending legs which define a recess therebetween into which is received the support member. In this way, the cover is adapted to be seated over an upper edge of the support member.

In one form the sub-frame further includes a fixing rail adapted to interengage a mid region of the screen frame. In this arrangement, the sub-frame includes a central fastening area which is cooperable with the fixing rail.

In a further aspect, the present invention provides a screen frame for supporting screen modules of an ore screening apparatus, said apparatus having a sub-frame and said screen frame including a pair of spaced apart side frame members providing opposite edge regions for securing said screen frame to said sub-frame, and a plurality of elongate frame members extending between said opposite edge regions in spaced apart parallel relation and 15 connected to said side frame members, said frame members being o.engageable by a support member of said sub-frame intermediate said edge regions to produce a camber in screen modules supported thereon and to locate the frame members relative to the support member.

In a further aspect, the invention provides a support member for use in a 20 support system for supporting screen modules of an ore screening apparatus, said support member having an elongate form and including locating slots in an upper region of said member for receiving and locating frame members of said support system, said locating slots extending transverse to the elongate extent of said support member.

In yet a further aspect, the present invention provides a cover for the above support member. The cover includes the locating means in this aspect.

In a further aspect, the present invention provides a screening apparatus including the above support system.

It will be convenient to hereinafter describe an embodiment of the invention in greater detail with reference to the accompanying drawings. The Sparticularity of these drawings in the related description is not to be understood KW W:\kate\SPECI\SCREENdoc -6as superseding the generality of the preceding broad description of the invention.

In the drawings: Fig. 1 is a plan view of a screen panel for a screening apparatus according to one 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 a screen module of the panel of Fig. 1; Fig. 5 is a partial transverse cross-sectional side view of the support system according to one embodiment of the present invention installed in a screening oo oi apparatus; 0. 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 a. 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 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 to 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 DG C:\WINWORD\DELILAHkCOMPLETE\SCREEN.DOC -7members 21. The side edge regions 20 are provided by spaced apart side 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 "i 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.

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The screen frame 13 further includes a central bolt down region 15 located intermediate and parallel to the opposite side edge regions 20. The °9 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.

As mentioned above, the screen modules 12 are adapted to be 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 interengage 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 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 DG C:\WIMNORD\DELILAHOMPLETE\SCREEN.DOC -8under 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 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 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 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 20 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 DG C:\WINWORD\DELILAH\COMPLETE\SCREEN.DOC -9through 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 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.

10 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 **aframe 13 into engagement with the support beam 51. In the illustrated 20 arrangement, the fastening assembly 53 includes a nut and bolt assembly with .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 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 DG C:WWINWORD\DELILAH\COMPLETE\SCREEN.DOG 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 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

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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 and includes a series of transverse grooves 62. The grooves 62 are shaped °e 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.

DG CAWWINWORD\DELILAHCOMPLETE\SCREENDOC -11 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 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 see.

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 20 walls 63 of the grooves 62. This assists in resisting screen frame distortion.

As 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.

Accordingly, the present invention provides a support system for screen modules which is more efficient in accommodating its design loadings.

Further, by incorporating the locating means as part of a separate cover, for mounting on the support members, the invention enables the system to be easily retro-fitted to existing screening apparatus.

DG C:\WINWORD\DELILAHCOMPLETE\SCREEN.DOC 12- 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.

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Claims (18)

1. A support system for screen modules of an ore screening apparatus, the system including: a screen frame for holding a plurality of screen modules in an array so as to form a screen panel providing an ore screening surface, the screen frame having a pair of opposite edge regions; and a sub-frame for operatively supporting the screen panel in the apparatus, the screen frame being securable to the sub-frame at the opposite edge regions, the sub-frame including at least one support member engagable with the screen frame intermediate its edge regions so that a camber is produced over the screening surface between the edge regions, and the support member having locating means for engaging the screen frame in order to maintain that frame in a predetermined position relative to the support member.

2. A support system according to claim 1, said screen frame including a plurality of frame members extending between said opposite edge regions, and said support member including a plurality of locating means engageable with respective ones of said frame members.

3. A support system according to claim 2, said screen modules including connection recesses which are configured to engagingly receive said o frame members therein for releasably securing said modules to said screen frame.

4. A support system according to claim 2 or 3, said frame members having the form of elongate frame bars, and said connection recesses having the form of keyhole slots which are shaped and sized to inter-engage in a snap-fit arrangement with said frame members.

5. A support system according to claim 4, said elongate frame bars being of substantially constant cross-section.

6. A support system according to any one of claims 2 to 4, said locating means including locating slots which receive respective ones of said frame members. DG C:\WINWORD\DELILAH\COMPLETE\SCREEN.DOC -14-

7. A support system according to claim 6, wherein said support member is elongate and said locating slots extend transverse to the elongate extent of said member.

8. A support system according to any one of claims 2 to 7, said locating means being integrally formed with said support member.

9. A support system according to any one of claims 2 to 7, wherein said locating means is formed in a cover mounted on a support bar of said support member.

A support system according to claim 9, wherein said cover is cast or moulded from a plastics material.

11. A support system according to claim 9 or 10, wherein said cover 0 :ol is internally reinforced by one or more metal elements.

12. A support system according to claim 11, wherein said metal elements are metal strips.

13. A support system according to claims 9 to 12, wherein said locating means are formed in an upper region of the cover.

14. A support system according to claims 9 to 13, said cover including spaced slots, suitable to receive fastening means to secure said cover to said support member.

15. A support system according to claim 14, said fastening means including bolts.

16. A support system according to any one of claims 9 to 13, said cover including a pair of downwardly extending legs defining a recess therebetween into which at least a part of said support bar is received.

17. A support system according to any one of claims 1 to 16, wherein said sub-frame includes engagement means for engaging and securing a mid region of said screen frame.

18. A support system according to claim 17, said engagement means including clamping means to clamp said screen frame mid region to said sub- frame. DG C:WNWORD\DELILAHCOMPLETE\SCREEN.OC