AU654091B2 - Screen panel fixing system - Google Patents

Description

AUST

Pate rn II: 2:

RALIA

nts Act 6b" 40 9 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Lettela Proprietary Limited Actual Inventor(s): Andrew Lambert Bernadou Raymond Maxwell Woodgate Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: SCREEN PANEL FIXING SYSTEM Our Ref: 339730 POF Code: 95/17556 The following statement is a f description of this invention, including the best method of performing it known to applicant(s): -1- SCREEN PANEL FIXING SYSTEM This invention relates generally to apparatus for screening, separating or grading materials, and in particular to a system for fixing screen panels to a support frame of such apparatus. The apparatus is applicable for screening, separating and grading ores and other materials and iu will be convenient to hereinafter describe the invention in relation to this exemplary application. It is to be appreciated, however, that the invention is not limited to such apparatus.

A variety of systems have been developed for fixing screen panels to a support frame whereby individual panels can be easily and rapidly removed and replaced when worn. In this way, screening effectiveness and efficiency of the apparatus can be maintained during operation without significant 0 .o o "downtime" requirements for screen panel maintenance. More 00 0 o: recently, these developments have concentrated on "no-bolt" systems in which the use of nuts and bolts for fixing the oeo screen panels has been avoided. Such systems have the added advantage of enabling the apparatus to be maintained by relatively unskilled persons, rather than skilled tradesmen in the case of "bolted" systems. In consequence, the cost of 9 maintenance may be minimised.

04 Part of one such "no-bolt" fixing system is disclosed in Australian patent application 27046/88. That application r 6 provides for the fixing of an outer side edge region of screen panels to the frame, the system including a clamp bar extending along a side wall of the frame and overlaying the side edge region so as to sandwich that side edge region between the clamp bar and frame. Wedge means a-e urranged to retain that clamp bar in its clamping position. The wedge means includes a series of reaction brackets mounted along the side wall of the frame above the clamp bar, and wedge members wedged between the brackets and clamp bar. Intermengaging surfaces of the wedge members and clamp bars are transversely angled so that forces applied by the wedge members press the clamp bars against the side edge regions of the screen panels and the side wall of the frame.

Although this wedge means arrangement eliminates the need for clamp bolts in the clamp bars, the wedge members may not satisfactorily retain the clamp bars in all screening 2 recesses, and thus dislocation of the screen panels during a screening operation. However, that stiffness can sometimes make deliberate replacement of individual panels difficult, particularly without damaging the connection ribs, and the edge regions of the replacement panels.

It is an object of the present invention to alleviate one or more of those difficulties through the provision of an improved fixing system.

It is another object to provide a screening apparatus incorporating the improved fixing system.

With these objects in mind, the present invention provides a system for fixing screen panels to a screen deck frame of an ore screening apparatus, the frame including an 00 0 elongate sub-frame structure having longitudinal edge regions .o and side structures extending along the edge regions of the 00000 0 0 sub-frame structure, the fixing system comprising: fixing means having elongate fixing members arranged to extend over 00.0 00. the sub-frame structure along and between opposed side edge regions of adjacent screen panels, each fixing member including a pair of connection portions extending longitudinally of the fixing members and being deflectable oo oo S relative to one another, cooperable connection means on each oo connection portion and an associated side edge region of the *a 0 screen panels for connecting the screen panels to the fixing 2,F o members, the connection portions being deflectable to connect and disconnect individual screen panels to and from, respectively, the fixing members.

00 00 00 0 The present invention also provides ore screening apparatus incorporating the above fixing system.

This invention is described herein with reference to the fixing system in a normal apparatus use orientation on a horizontally extending footing, and terms such as "upper" and "lower" should be construed in the light of this orientation.

However, it is to be appreciated that other orientations may be equally possible and that consequential changes in terms such as those above may be required in the light of those other orientations for a proper and complete understanding of the invention.

Each fixing member preferably includes a base portion from which the connection portions upstand. The connection 3 L? r

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portions are preferably laterally spaced apart and resiliently deflectable, relative to the base portion, toward one another into the space between the connection portions. In one preferred arrangement, each fixing member is a fixing rail of generally U-shaped cross-sectional profile.

Preferably, the connection means includes connection elements at outer side surfaces of the connection portions and on side edge faces of respective adjacent screen panels.

These connection elements interengage to hold the screen panels in position, deflection of the connection portions disengaging the connection elements to disconnect the screen panels from the fixing members. In one preferred arrangement, the connection elements include at least one connection rib 00 0 0: and connection groove. At least one connection rib may be 0 90 provided on each connection portion and each associated screen o panel. Moreover, at least one connection groove may be 0 0 provided in each connection portion and each associated screen oo0 6000 panel. These ribs and grooves of the connection portions and associated screen panels interconnect to connect the screen panels to the fixing members, in this arrangement.

Preferably, the fixing means further includes a S plurality of retaining members. These members extend along 0 0the fixing members and engage the connection portions to 00 resist their inadvertant deflection. Preferably, each 00 2 5, retaining member includes a retaining strip for projecting into the space between the connection portions and engage the connection portions to prevent their inward deflection. In 00 0 Sone preferred arrangement, each retaining strip includes an elongate plug portion. The plug portion extends along the space between the connection portions of each fixing member, and urges the connection portions outwardly away from one another into connection with the screen panels and laterally urging the screen panels toward a facing side structure. Each retaining strip also includes, in this arrangement, a cover portion for extending along and overlying the fixing member to cover the space between the connection portions thereof. This cover portion may have a lateral extent so as to also overlie the side edge regions of the adjacent screen panels, the cover portion having a pair of lower surfaces each being sealably engageable upon a respective connection portion and associated 4 screen panel. In this way, ingress of ore fines and paste between the fixing member and screen panels is inhibited.

The apparatus preferably further includes dam means extending across the screen deck between adjacent upstream and downstream screen panels. The dam means preferably includes a series of elongate dam members, each extending between an adjacent pair of fixing members. In one preferred arrangement, each dam member includes a dam slat bridging between adjacent screen panels and bearing on the upper surface thereof. Moreover, a mounting strip extends along and depends from the dam slat for projecting between juxtaposed end edge faces of the adjacent screen panels to secure the dam member in position.

•Each dam member extends between spaced apart retaining members and may have ends positioned adjacent respective S retaining members. Where this occurs, the dam means further includes dam elements on the retaining members extending 004* between the ends of adjacent dam members so as to provide a continuous dam between the adjacent dam members over the retaining members.

The following description refers to a preferred embodiment of the fixing system and apparatus of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying tIt 2I drawings where the fixing system and apparatus are illustrated in that preferred embodiment. It is to be understood that the fixing system apparatus are not limited to the preferred 41IC S embodiment as hereinafter described and as illustrated in the drawings.

In the drawings: Fig. 1 is a perspective view of a region of an ore screening apparatus according to a preferred embodiment of the present invention and showing a preferred fixing system of the present invention incorporated therein; Fig. 2 is a part end view of the fixing system in Fig. 1 showing the profile of a fixing rail; Fig. 3 is a part end view of the fixing system in Fig. 1 showing the profile of a side edge region of a screen panel; Fig. 4 is a part end view of the fixing system in Fig. 1 showing the profile of a retaining strip; 5 Fig. 5 is a cross sectional view through Section V-V of the fixing system of Fig. 1 showing the profile of a dam member; Fig. 6 is an underneath perspective view of a clamp bar of the fixing system of Fig. i.

Fig. 7 is an end view if the screening apparatus of Fig, 1 but showing the installation of a screen panel between fixing rails; and, Fig. 8 is a series of end views of part of the screening apparatus of Fig. 1 but showing removal of a screen panel from between fixing rails.

Referring initially to Fig. 1 of the drawings there is o, generally shown an ore screening apparatus 1 for screening, S: separating and grading ores and other materials M. Materials o o M move through the apparatus 1 during screening in the direction of feed arrow F.

e de o 0 0 0 0 00.. The apparatus 1 includes a screen deck frame 2 which has 0000 o an elongate sub-frame structure 3 comprising parallel, spaced apart sub-frame support beams 4 extending along the apparatus I. The sub-frame structure 3 has longitudinal edge regions along which side structures 6 extend. The side structures 6 Seach comprise side beams 7 (only one of which is shown).

06 An array of screen panels 8 are fixed to, and supported by, the screen deck frame 2 to form the continuous screen 0000 2& deck. Each screen panel 8 extends between and is supported by a pair of the support beams 4. Each screen panel 8 is typically flat, and square or rectangular plan shape, with an S upper screening surface 9 for receiving ore or other material M to be screened and a lower bearing surface 10 that bears on the support beams 4. Each screen panel 8 has a pair of opposed side edge regions 11 with side edge faces 12 and a pair of opposed upstream and downstream end edge regions 13 with end edge faces 14. Apertures 15 extend through the screen panels 8 between the screening and bearing surfaces 9, 10 to provide for ore screening and separation.

The screen panels 8 are cast or molded from plastics material, such as polyurethane, and may be internally reinforced with one or more metal elements, such as steel bars (not shown). It should he appreciated that alternative materials and methods of production may be equally suitable.

6

V

The apparatus 1 provides a fixing system 16 for releasably fixing the screen panels 8 to the screen deck frame 2, and in particular the sub-frame structure 3.

The fixing system 16, in this embodiment of the present invention includes a plurality of fixing members 17 which, in this embodiment, are in the form of elongate fixing rails.

Each fixing rail 17 extends along a respective support beam 4 so that the fixing rails 17 are in parallel spaced apart relation and positioned between adjacent screen panels 8.

Each fixing rail 17 includes an elongate base portion 18 and a pair of connection portions 19 extending along and upstanding from the base portion 18. The connection portions 19 are 0 laterally spaced apart so as to define clearance groove 00 0 S therebetween. Thus, in this embodiment, each fixing rail 17 has a generally U-shaped cross sectional profile, providing S the base portion 18 and connection portions 19 with the clearance groove 20 therebetween.

0000 0oo Each fixing rail 17 has a pair of opposite outer side surfaces 21 provided by the base portion 18 and respective connection portions 19, and a pair of opposed inner side surfaces 22 provided by the respective connection portions ee o S 19. Each connection portion 19 also has a free end surface 23 remote from the base portion 18. Each fixing rail 17 is sized relative to the screen panels 8 so that, in use, the upper J screening surface 9 of the adjacent screen panels 8 lie flush with the free end surfaces 23 of the connection portions 19.

As shown, the fixing rails 17 may be the same height as the r0 0 S thickness of the screen panels 8.

The fixing rails 17, or at least the connection portions 19, are composed of resiliently, flexible material to enable the connection portions 19 to deflect relative to the base portion 18 and one another into the clearance groove 20. In this embodiment, the fixing rails 17 are cast or molded in one piece from plastics material, such as polyurethane, and may be internally reinforced with one or more metal elements, such as steel plates (not shown). It should be appreciated that alternative materials and methods of production may be equally suitable.

The fixing rails 17 are mounted on the sub-frame structure 3 through any suitable arrangement. In this i;

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j:; 7 embodiment, the rails 17 are bolted to the underlying support beams 4 fthe sub-frame structure 2 by means of bolts 24 carried by the base portion 18 and depending therefrom through apertures (not shown) in the beams 4.

Connection elements 25 are provided on the outer side surfaces 21 of the connection portions 19 and on a side edge face 12 of respective adjacent screen panels 8, those connection elements 25 interengaging to hold the screen panels 8 in position on the sub-frame structure 2. These connection elements 25 are arranged so that deflection of the connection portions 19 disengages the connection elements 25 to enable disconnection of the screen panels 8 from the fixing rails oo2 17. The connection elements 25 are integral with the fixing Srails 17 and screen panels 8, in this embodiment.

The connection elements 25 are shown in more detail in 0 the fixing rail 17 and screen panel of Figs. 2 and 3, ~o~o~respectively, and include at least one connection rib 26 and .09 connection groove 27, with at least one rib 26 being provided on each connection protion 19 and/or each associated screen panel 8, and at least one groove 27 being provided in each connection portion 19 and/or each associated screen panel 8.

The ribs 26 and grooves 27 extend longitudinally of the connection portions 19 of the fixing rails 17 and the side edge regions 11 of the screen panels 8.

In the emnbodiment shown, each connection portion 19 has one connection rib 26 and one connection groove 27, and each associated screen panel side edge region 11 is similarly 0 4provided with one connection groove 27 and one connect.ca rib 26 for interengagement therewith. In this embodiment, the connection groove 27 of each connection portion 19 is formed in the outer side surface 21 adjacent the base portion 18. In addition, in this embodiment, each outer side surface 21 adjacent the free end surface 23 has a relieved region 28 s0 as to define the connection rib 26 between the connection groove 27 and relieved region 28. Each associated screenJ panel side edge region 11 has the connection groove 27 formed adjacent the upper screening surface 9 of the screen panel 8 for receiving a connection rib 26 therein, and has a relieved region 29 adjacent the lower bearing surface 10 so as to define the connection rib 26 between the connection groove 27 8and relieved region 29 for engaging in a connection groove 27. In this embodiment, the outer side surfaces 21 of the connection portions 19 and screen panel side edge faces 12 are substantially complementarily profiled so as to engage face-to-face over their lateral and longitudinal extent.

To ensure that the connection portions 19 do not inadvertently deflect during apparatus operation, and thus accidentally release screen panels 8, the fixing system 16 further includes a plurality of elongate retaining members arranged to extend along the fixing rails 17 and engage the connection portions 19 to resist their deflection.

One retaining member 30 is shown in more detail in Fig.

o 4, and includes a retaining strip 31 arranged to project into the clearance groove 20 between the connection portions 19, o and engage those portions 19 to prevent their inward 0 deflection. Thus, in effect, the strips 31 act to at least substantially fill the groove 21 into which the connection oo portions 19 would otherwise deflect. The strips 31 are removably insertable into the grooves 20, being readily removed when it is desired to remove or replace an adjacent screen panel 8. In this embodiment, the strips 31 are S manually press fitted into and pulled from the clearance 9409 :s grooves Each retaining strip 31 includes an elongate plug portion 32 for extending along and substantially filling the clearance groove 20 in the fixing rail 17. To that end, the plug portion 32 is at least substantially complementarily S shaped to the clearance groove The plug portion 32 of each retaining strip 31 may be an interfering fit in the clearance groove 20 to facilitate its retention during apparatus operation. The retention may be further insured by providing cooperable retaining elements 33 on the plug portion 32 and connection portions 19. In this embodiment, the retaining elements 33 include one or more cooperable retaining ribs 34 and grooves 35 extending along the surface(s) of the plug portions 32 and the inner side surface(s) 22 of the connection portions 19.

The retaining members 30 can also act to cover over joints formed between the screen panels 8 and fixing rAils 17 to inhibit ingress of any ore fines or paste therebetween 9 which could otherwise wear the connection elements 25 causing the screen panels 8 to work loose. To that end, each retaining strip 31 also includes an elongate cover portion 36 arranged to overlie the fixing rail 17 and the side edge regions 11 of the adjacent screen panels 8. Each cover portion 36 is connected to the respective plug portion 32, and in this particular embodiment the cover portion 36 and plug portion 32 of each retaining strip 31 are formed integral with one another. The cover portion 36 has a pair of lower surfaces, each being sealably engageable upon respective free end surfaces 23 of the connection portions 19 and upper screening surfaces 9 of the adjacent screen panels 8.

In this embodiment, the retaining strips 31 have a t S generally T-shaped profile, the upright portion providing the plug portion 32 and the cross portion providing the cover portion 36.

In this embodiment, the retaining strips 31 are cast or St,, molded from plastics material, such as polyurethane, although it should be appreciated that alternative materials and method of production may be equally suitable.

In the event that ore fines or paste do work into the clearance grooves 20, the fixing rails 17 may be provided with drain apertures (not shown) from those grooves 20. The apertures may be provided by drain slots extending through the connection portions 19 and/or the base portions 18 of the fixing rails 17.

Referring again to Fig. i, the fixing system 16, may 4 L also include a plurality of clamp members 37 extending along the side beams 7 so that the outermost side edge regions 11 of the screen panels 8 adjacent the side beams 7 are positioned between the clamp members 37 and the underlying sub-frame structure 2. In this embodiment, each clamp member 37 is in the form of a clamp bar, with upper and lower longitudinal side edge regions 38,39 respectively providing a force transmitting surface 40 and a clamping surface 41 for engaging the side edge regions 11 of the screen panels 8. In this embodiment, each clamp bar 37 is of a generally rectangular cross sectional shape, with inner and outer surfaces 42,43 extending between the side edge regions 38,39, the inner surface 42 facing inwardly toward the screen panels 8 and the 10 outer surface 43 contacting the side beams 7 during fixing system use.

The fixing system 16 also includes force applying means 44 for forcing the clamp bars 37 into contact with their respective screen panels 8 and side beams 7. The force applying means 44 includes a plurality for force applying members 45 which, in this embodiment, are in the form of wedge blocks for wedging against the clamp bar 37 to apply a force thereto. Each wedge block 45 has a lower force transmitting surface 46 for engaging upon the force transmitting surface of a respective clamp bar 37, and an upper force reaction surface 47.

In this embodiment, the force applying means 44 also includes a plurality of reaction members 48 for mounting on the side beams 7 and between which and an adjacent clamp bar 37 a respective wedge block 45 is wedged, the wedge block oo reacting against the reaction member 48 to apply the clamping oror 9 force to the clamp bar 37.

In this embodiment, each reaction member 48 includes a reaction bracket 49. Each reaction bracket 49 has a reaction leg 50 positioned in spaced relation from a respective clremp S bar 37 so that a respective wedge block 45 wedges between the 41C reaction leg 50 and the clamp bar 37, and a retaining leg 51 spaced from the side beam 7 so that the wedge block 45 fits S between the retaining leg 51 and side beam 7.

Fach wedge block 45 is longitudinally tapered between the force transmitting surface 46 and force reaction surface 0* *I S 47, and the reaction leg 50 of the reaction bracket 49 is compatibly longitudinally angled to achieve the wedging affect. Alternate reaction brackets 49 may be similarly (not shown) or oppositely (as shown) angled.

It should be appreciated that alternative releasable force applying means 44 may be provided. By way of example, that means 44 may provide force applying members 45 including cams (not shown) mounted for movement into and out of force applying engagement with the clamp bars 37. Those cams may be mounted on the side beams 7 for linear or rotational movement to achieve a caming effect similar to the wedging effect of the wedge blocks The force transmitting surfaces 40 and 46 are laterally KW -11 9'

I

profiled to provide separate surface portions 52,53 through which forces are transmitted to urge the clamp bars 37 into contact with the screen panels and into contact with the side beams 7, respectively. In this embodiment, the force transmitting surfaces 40,46 are laterally stepped so as to provide the separate surface portions 52,53. Those surface portions 52,53 are arranged perpendicular to one another, in this embodiment. Moreover, in this embodiment, when the force transmitting surfaces 40,46 are interengaging, horizontal stepped surface portions 52 are provided to urge the clamp bars 37 into contact with the screen panels 8, and vertical stepped surface portions 53 are provided to urge the clamp bars 37 into contact with the side beams 7.

In this embodiment, the lower longitudinal side edge regions 39 of the clamp bars 37 are shaped and sized so as to fit or mate with the side edge regions 11 of adjacent screen panels 8 and thereby facilitate screen panel fixing. To that Poo end, the lower side edge region 39 of each clamp bar 37 is laterally stepped so as to provide a relief recess 54 therealong adjacent the inner surface 42 of the clamp bar 37 and into which an upper corner of the side edge regions 11 of screen panels 8 are received. In this way, the clamp bars 37 4 not only clamp down onto the upper surface 9 of the screen panels 8, but also fit into a gap 55 between the screen panels 544' 2, t 8 and adjacent side beams 7. That fit can be interferance fit so as to apply a force to the panel 8 in the plane of, and transversely of, the panel 8. This acts to press the screen panel 8 into engagement with a fixing rail 17 associated therewith.

The engagement between the clamp bars 37 and side edge face 12 of the screen panels 8 may be continuous (not shown) or discontinuous (as shown) along the length thereof. The clamp bars 37 each have a relief face 56 defining the relief recess 54. That relief face 56 may be flat (not shown) for face-to-face engagement with the side edge faces 17 of the screen panels 8 to achieve continuous engagement. However, for discontinuous engagement, the relief face 56 is provided (as shown) with a series of spaced apart protruberances 57 which engage the side edge faces 12. Those protuberances 57 are positioned so as to be located inwardly of the end edge 12 faces 13 of the screen panels 8.

The apparatus 1 also includes dam means 58 extending across the screen deck between adjacent upstream and downstream screen panels 8, and upstanding from the upper surfaces 9 thereof. In this embodiment, the dam means 58 includes a series of elongate dam members 59, each extending between an adjacent pair of fixing rails 17.

One dam member 59 is shown in more detail in Fig. 5, and includes a dam slat 60 bridging between adjacent upstream and downstream screen panels 8 and bearing on the upper surfaces 9 thereof. Each dam slat 60 is of rectangular cross sectional shape.

Each dam slat 60 has end regions 61 which, in one 0o embodiment (not shown), are shaped to fit partially over the 15 retaining strips 31 to abut end-to-end and so form a 4-00 continuous dam wall across the screen deck.

°o-o In an alternative embodiment (as shown), the end regions 0 bso o9 0 61 of adjacent dam slats 60 terminate spaced from one another over the retaining strips 31. Where that occurs, dam elements 62 are provided on the retaining strips 31 extending between the spaced apart dam slat end regions 61, and so presenting a 00o 0 0 continuous dam wall. Those dam elements 62 each have an 06.q upstream surface 63 which extends straight across the retaining strip 31 in this embodiment, whilst in another 0000 2 embodiment (not shown) is angled so as to divert materials being screened off the retaining strip 31 onto the screen deck. These dam elements 62 are formed integral with the S retaining strips 31. As shown, in this embodiment, additional dam elements 64 may be positioned in spaced relation along the retaining strips 31 between the dam elements 62 so as to further facilitate diversion of screening materials M onto the screen panels 8.

The dam members 59 are removably mounted on the screen i deck. To that end, each dam member 59 also includes a mounting strip 65 extending along and depending from the dam slat 60 for projecting between juxtaposed end edge faces 13 of adjacent upstream and downstream screen panels 8. In this embodiment, each inounting strip 65 has an L-shaped profile so as to extend between the screen panels 8 and then return beneath one of those panels 8.

13 In this embodiment, the dam slats 60 are cast or molded from plastics material, such as polyurethane, with the mounting strips 64 being composed of metal, such as stainless steel, partially embedded into the dam slats 60. It should be appreciated that alternative materials and methods of production may be equally suitable.

Installation of a screen panel 8 into the apparatus 1 using the fixing system 16 is shown in detail in Fig. 7. With the fixing rails 17 mounted on the support beams 4, and the retaining strips 31 removed, a screen panel 8 is orientated so as to be above a space extending between a pair of adjacent fixing rails 17. The screen panel 8 is then manoeuvered until one side edge region 11 is presented to a respective connection portion 19 of one fixing rail 17 and an opposite o side edge region 11 is above the connection portion 19 of the a adjacent fixing rail 17. This position of the screen panel 8 is shown at the left hand side of the Fig. 7 drawing.

The screen panel 8 is then pivoted about the one side edge region 11 so that the other side edge region 11 moves toward the adjacent fixing rail as indicated by arrow A. This causes the connection elements 25 at the one side edge region 11 to pivotably move into engagement, and toward connection •0 with, the connection elements 25 at the respective connection portion 19. This pivoting of the screen panel 8 continues until the opposite side edge region 11 contacts its respective connection portion 19.

Manual downward force is then applied to the screen panel 8 at the opposite side edge region 11. This force transmits to the respective connection portion 19 causing it to deflect into the adjacent clearance groove 20. The connection portion 19 adjacent the one side edge region 11 may also deflect to some extent under this applied force. The connection portion deflection enables the opposite side edge region 11 to move into a final face-to-face position with the respective connection portion 1l the connection portion 19 returning to its non-deflected position as the connection elements 25 at that opposite side edge region 11 interengage with the connection elements 25 of the connection portion 19.

With screen panels 8 connected to both connection portions 19 of the fixing rail 17, the retaining strip 31 is 14 then fitted into position. Orientating the strip 31 as shown in the Fig. 7 drawing, the strip 31 is moved toward the fixing rail 17 in the direction of arrow B. This causes the plug portion 32 to enter clearance groove 20 until interconnection between retaining ribs 34 and grooves 35 secures strip 31 in position. In this position, cover portion 36 overlies fixing rail 17 and the adjacent side edge regions 11 to inhibit ingress of ore fines and paste therebetween. The flexibility of retaining strip 31 allows it to be fitted into, and removed from, clearance groove 20 progressively along the length of the strip 31.

Where the screen panels 8 are located adjacent the side .oo. beams 7 then they will connect with only one fixing rail 17 at 0 0 the one side edge region 11. The opposite side edge region 11 will be fixed with clamp bars 37 and wedge blocks 45. In this case, with the screen panels 8 in position, the clamp bars 37 o 000 are laid along the side structures 6 so as to be positioned ooe flat against the side beams 7 with the lower longitudinal side edge regions 39 fit or mate with the upper corners of the opposite side edge regions 11. Wedge blocks 45 are then driven in beneath the reaction brackets 49 so as to apply 00 *9 S clamping forces to the clamp bars. Those clamping forces S transmit forces through surface portions 52 to clamp the screen panel side edge regions 11 between the clamp bars 37 o' oo and the underlying support beams 4, and through the surface portions 53 to maintain the clamp bars 37 in face-to-face engagement with the side beams 7.

Removal of a screen panel 8 is generally a reverse of the above outlined installation procedure. However, as shown in the series of drawings of Fig. 8, removal of an individual screen panel 8 involves the use of a screw driver or similar tool T.

The blade of the tool T is initially inserted between one of the connection portions 19 and the cover portion 36 of the retaining strips 31 in order to partially prise the strip 31 from the clearance groove 20 (Fig. The strip 31 can then be manually gripped and pulled away to disconnect it from the fixing rail 17.

The blade of the tool T is then inserted between a side edge face 12 of the screen panel 8 and the associated 15

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connection portion 10 of the adjacent fixing rail 17. That blade enters into the relieved region 28 of the connection portion 19 (Fig. By manoeuvering the tool T, the connection portion 19 can be deflected into the clearance groove 20. This withdraws the connection rib 26 of the connection portion 19 from the connection groove 27 of the screen panel 8 (Fig. Continued manoeuvering of the tool T inserts the blade deeper between the screen panel 8 and fixing rail 17 (Fig. whereupon pivoting of the tool T on the deflected connection portion 19 levers the side edge region 11 of ie screen panel 8 upward and out of engagement with the fixing rail Fig. As the screen panel side edge region 11 clears above the fixing rail 17, the panel 8 can be 0 o 4 manually gripped and drawn away from the fixing rail 17 connecting the opposite screen panel side edge region 11, thus 0 releasing the screen panel 8 from the screen deck.

The fixing system of the present invention provides for simple and rapid removal and replacement of individual screen panels from ore screening apparatus. In particular, that can be achieved by unskilled labour using a minimum of ordinary tools. Moreover, screen panel removal and replacement with S° this fixing system ensures a minimum amount of apparatus "downtime", thereby providing the opportunity of increased 00 apparatus productivity.

Z4j' Finally, it is to be understood tha-at rious modifications and/or alterations may be to the screen panel fixing system and appar without departing from the ambit of the pres invention as defined in the claims appende e o.

16

Claims (14)

1. A system for fixing screen panels to a screen deck frame of an ore screening apparatus, the frame including an elongate sub-frame structure having longitudinal edge regions and side structures extending along the edge regions of the sub-frame structure, the fixing system including: fixing means having elongate fixing members arranged to extend over the sub-frame structure along and between opposed side edge regions of adjacent screen panels, each fixing member including a pair of connection portions extending longitudinally of the fixing members and being deflectable relative to one another, cooperable connection means on each connection portion and an o, associated side edge region of the screen panels for connecting the screen panels to the fixing members, the connection portions being deflectable to connect and disconnect individual screen panels to and from, respectively, the fixing members.

2. A fixing system as claimed in claim i, wherein each fixing member includes a base portion from which the connection portions upstand, the connection portions being laterally spaced apart and resiliently deflectable relative to S the base portion toward one another into the space between the ooconnection portions.

3. A fixing system as claimed in claim 2, wherein each fixing member is a fixing rail of generally U-shaped cross-sectional profile providing the base portion and connection portions with a clearance groove therebetween. S4. A fixing system as claimed in any preceding claim, wherein the connection means includes connection elements provided at outer side surfaces of the connection portions and at side edge faces of respective adjacent screen panels, the connection elements of each connection portion and an associated screen panel interengaging to hold the screen i panels in position, deflection of the connection portions disengaging the connection elements to disconnect the screen panels from the fixing members. A fixing system as claimed in claim 4, wherein the respective connection elements are integral with the connection portions and screen panels.

6. A fixing system as claimed in claim 4 or 5, wherein the KW 17- connection elements include at least one connection rib and connection groove, at least one connection rib being provided on each connection portion and/or each associated screen panel, and at least one groove being provided in each connection portion and/or each associated screen panel, the ribs and grooves of the connection portions and associated screen panels interconnecting to connect the screen panels to the fixing members.

7. A fixing system as claimed in claim 6, wherein each connection portion has one connection rib and one connection groove, and each associated screen panel also has one connection groove and one connection rib for interengagement therewith. S 8. A fixing system as claimed in any preceding claim, wherein the connection portions connectably engage with the associated side edge region of the screen panels and laterally urge the screen panels toward a facing side structure.

9. A fixing system as claimed in any preceding claim, wherein the fixing means further has a plurality of retaining members arranged to extend along the fixing members and engage thereby causing disconnection from the screen panels. A fixing system as claimed in claim 9, wherein each retaining member includes a retaining strip for projecting into the space between the connection portions and engage the connection portions to prevent their inward deflection toward one another. S 11. A fixing system as claimed in claims 9 or 10, wherein each retaining strip includes an elongate plug portion for extending along the space between the connection portions of each fixing member and urging the connection portions outwardly away from one another into connection with the screen panels and laterally urging the screen panels toward a facing side structure.

12. A fixing system is claimed in claim 11, wherein each plug portion is shaped and sized so as to be an interfering fit in the space between the connection portions.

13. A fixing system as claimed in claim 11 or 12, wherein each connection portion and plug portion has cooperable retaining elements interacting when the plug portion is in the 18 space between the connection portions of each fixing member to resist retaining strip removal.

14. A fixing system as claimed in claim 13, wherein the cooperable retaining elements are interengageable retaining ribs and grooves extending along surfaces of each connection portion and plug portion. A fixing system as claimed in any one of claims 11 to 14, wherein each retaining strip also includes a cover portion for extending along and overlying the fixing member to cover the space between the connection portions thereof.

16. A fixing system as claimed in claim 15, wherein each cover portion has a lateral extent so as to also overlie the *side edge regions of the adjacent screen panels, the cover it, portion having a pair of lower surfaces each being sealably engageable upon a respective connection portion and associated s screen panel to inhibit ingress of ore fines and paste therebetween.

17. A fixing system as claimed in claim 15 or 16 wherein the plug portion and cover portion of each retaining strip are integral with one another, and each retaining strip is of a generally T-shaped profile. S 18. An ore screening apparatus, including: a screen deck frame including an elongate sub-frame structure having longitudinal edge regions and side structures extending along S the edge regions thereof; an array of screen panels fixed to the screen deck frame to form a continuous screen deck; and, a fixing system as claimed in any preceding claim for fixing the 1,1 .i -h lnaefxn screen panels to the screen deck frame, the elongate fixing members being arranged on the sub-frame structure in parallel spaced apart rows so as to receive screen panels between adjacent fixing member rows.

19. Apparatus as claimed in claim 18, and further including dam means extending across the screen deck between adjacent upstream and downstreem screen panels, and upstanding from an upper surface of the screen deck, the dam means including a series of elongate dam members, each extending between adjacent rows of fixing members. Apparatus as claimed in claim 19, wherein each dam .%AIA 4 member includes a dam slat bridging between adjacent upstream 4 and downstream screen panels and bearing on the upper surface KW 19 *1r I thereof, and a mounting strip extending along and depending from the dam slat for projecting between juxtaposed end edge faces of adjacent upstream and downstream screen panels.

21. Apparatus as claimed in claim 19 or 20 when appended to any one of claims 9 to 17, wherein each dam member extends between spaced apart retaining members and has ends positioned adjacent respective retaining members, and the dam means further includes dam elements on the retaining members extending between the ends of adjacent dam members so as to provide a continuous dam between the adjacent dam members over the retaining members.

22. Apparatus as claimed in claim 21, wherein each dam element is angled between the retaining member ends so as to divert ore materials being screened off the retaining members 1s 15 onto the screen deck. GE .411 00 0 0 0 DATED: 2 September, 1993 PHILLIPS ORMONDE FITZPATRICK Attorneys for: LETTELA PTY. LTD. 0 041~ 9119E 20 ABSTRACT An ore screening apparatus and a system (16) for fixing screen panels to a screen deck frame of the apparatus The fixing system includes: elongate fixing members (17) extending over a sub-frame structure (3) along and between opposed side edge regions (11) of adjacent screen panels Each fixing member (17) includes a pair of connection portions (19) extending longitudinally of the fixing members (17) and being deflectable relative to one another. Cooperable connection means are provided on each 0 connection portion (19) and an associated side edge region 0o4 (11) of the screen panels for connecting the screen panels o: uo to the fixing members The connection portions (19) are deflectable to connect and disconnect individual screen panels to and from, respectively, the fixing members (17). 0 S ^o