AU2019375922A1 - Screening apparatus - Google Patents

Abstract

A screening apparatus comprises a screen deck, a clip rail (60) attached to the screen deck, first and second screens (10) positioned such that upper parts (88) of upwardly extending parts of the clip rail (130) extend through the openings (38) between the members (28) and respective side edges (16) of the screen (10), and a locking strip (130) has the central downwardly extending portion (148) of the locking strip (130) extending downwardly into a space between the first and second upwardly extending parts of the clip rail (60).

Description

TITLE

Screening Apparatus TECHNICAL FIELD

[0001] The present invention relates to a screen for use in screening apparatus used in mining or mineral treatment operations. The screen may also be referred to as a screen panel or a screen media. The present invention also relates to a screening assembly for use in mining or mineral treatment operations. The present invention also relates to a locking strip for locking screens to a screening apparatus used in mining or mineral processing operations. The present invention also relates to a locking strip for locking screens to a clipping rail used in mining or mineral processing operations.

BACKGROUND ART

[0002] Mining and mineral treatment processes frequently use screening apparatus to separate particles of ore, concentrate, coal or other particulate material according to particle size. Many screening apparatus comprise a deck to which replaceable screens are mounted. The screening deck may have a plurality of screens replaceably mounted thereto. As the screens are operated to separate particulate material according to size or to effect dewatering of a slurry or pulp containing the particulate material, the screens wear and will need to be replaced.

Replacement of screens necessarily entails downtime when the screening apparatus is not in use.

[0003] Replacement of screens may require that operators remove worn screens and replace them with new screens in regions where access is restricted or difficult. This has the potential to considerably increase the time required to replace screens and to cause significant Occupational Health & Safety issues.

[0004] A number of screen assemblies have been proposed in order to enable screens to be replaced on screening decks. As or characteristics of such screen assemblies includes ease of removal of the screens from the screen deck whilst also ensuring that the screens are firmly held in place on the screen deck during screening operations.

[0005] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION [0006] The present invention is directed to a screen, a screening assembly, a locking strip for locking a screen to a screen deck, and a clipping rail, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0007] With the foregoing in view, the present invention in one form, resides broadly in a screen for use with a screening apparatus, the screen being adapted to be replaceably mounted to the screening apparatus, the screen comprising a panel having a plurality of screening apertures, the panel having a first pair of opposed edges and a second pair of opposed edges, the first pair of opposed edges having a member, each member being attached to its respective edge and being spaced from its respective edge such that at least one opening is defined between each member and its respective edge, the opening having an open top and an open bottom.

[0008] As mentioned above, this industry also uses the terms“screen panel” and“screen media” to describe the screen of the first aspect of the present invention.

[0009] In some embodiments, each member comprises an elongate member. In some embodiments, each elongate member extends along a length of its respective edge.

[0010] For convenience, the member on each edge of the first pair of opposed edges will be referred to hereinafter as the elongate member.

[0011] In one embodiment, the opening is adapted to receive an upwardly extending part of a clip rail attached to a screen deck of the screening apparatus. In one embodiment, the opening is adapted to enable the upwardly extending part of the clip rail to pass through the bottom of the opening and extend through top of the opening such that a portion of the upwardly extending part of the clip rail is located above an upper part of the elongate member.

[0012] In one embodiment, each elongate member is attached to the respective side edge at a plurality of points or regions. In these embodiments, a plurality of openings are defined between the elongate member and its respective edge, with each opening being defined by the elongate member, the respective edge, and adjacent attachment points or regions.

[0013] In one embodiment, the elongate members are integrally formed with the panel. For example, the panel and elongate members may be formed by injection moulding or other moulding process. In another embodiment, the elongate members are formed as separate items and are attached to the panel. [0014] In one embodiment, a lower edge of the member is positioned above the lower edge of the screen. In another embodiment, a lower edge of the elongate member includes an upwardly extending recess. In both of these embodiments, a flat blade or hook of a removal tool can be located under the lower edge of the elongate member or in the upwardly extending recess in the lower edge of the elongate member to enable the blade or hook to facilitate removal of the screen from a screening apparatus. In an alternative embodiment, one or more recesses or slots could be formed in the side of the members such that a flat blade or a hook or a plate could be used to engage with those recesses to facilitate removal of the screen from the screen deck.

[0015] In one embodiment, the screen is provided with regions extending outwardly from the opposed edges of the screen. These regions may engage with corresponding or

complementary shaped regions on a locking strip to thereby prevent creep of the locking strip along the screen during use.

[0016] As will be known to person skilled in the art, the panel may be made from a plastic material, such as polyurethane or mbber. The panel may include a frame, such as a metal frame or other reinforcement material, which provides additional strength to the panel. The metal frame may be enveloped by the plastic material. Details of this type construction will be well known to person skilled in the art in the art and need not be described further.

[0017] In a second aspect, the present invention provides a clip rail for attachment to an underlying screen deck of a screening apparatus, the clip rail adapted to facilitate attachment of a screen in accordance with the first aspect of the present invention to the underlying screen deck, the clip rail comprising a first upstanding part and a second upstanding part, the first upstanding part having an upper portion that is spaced from an upper portion of the second upstanding part, the first upstanding part extending through the opening of a first screen, the second upstanding part extending through the opening of a second screen.

[0018] In one aspect, the first upstanding part and the second upstanding part are resilient, or resilient and flexible.

[0019] The clip rail will have a length and a width and a height, which can vary to suit various screening apparatus (screening apparatus may also be called screening machines) and panel thickness of the replaceable screens. The upper portion of the first upstanding part may suitably be spaced from the upper portion of the second upstanding part in a direction across the width of the clip rail.

[0020] In one embodiment, the clip rail comprises a plurality of clips, with the clips being spaced from each other in a direction along a length of the clip rail, each clip comprising the first upstanding part and the second upstanding part. In this embodiment, the first upstanding part of each of the clips is received in an opening of the first screen and the second upstanding part of each of the clips is received in an opening of the second screen.

[0021] In one embodiment, the first upstanding part has a first lateral projection above a lower part of the first upstanding part and a second lateral projection spaced above the first lateral projection, and the second upstanding part has first lateral projection spaced above the lower part of the second upstanding portion and a second lateral projection spaced above the first lateral projection, the lateral projections of the first upstanding part facing the lateral projections of the second upstanding part. In some embodiments, the first lateral projections are opposed to each other and form a region of reduced space between the first upstanding part and the second upstanding part. Similarly, the second lateral projections are opposed to each other and form a region of reduced space between the first upstanding part and the second upstanding part. In this manner, the elongate members of the first screen and of the second screen may be positioned such that the elongate members are positioned below the first lateral projections and a region of a locking bar or locking strip may be positioned such that it is located below the second lateral projections and above the elongate members of the first screen and the second screen, when the first screen and the second screen mounted to the clip rail.

[0022] In one embodiment, the clip rail comprises a base portion, with the upstanding portions extending upwardly relative to the base portion. The base portion may include attachment regions or attachment means for attaching the clip rail to the screen deck. Suitably, the attachment regions or the attachment means are located underneath the clip rail. This will minimise the potential for damage being caused to the attachment regions or attachment means during use.

[0023] In some embodiments, the upstanding portions are spaced inwardly from each end of the base portion of the clip rail.

[0024] In some embodiments, the first upstanding part and the second upstanding part have an outer surface at which a lower region is further spaced from a longitudinal axis of the clip rail than an upper region is spaced from the longitudinal axis of the clip rail.

[0025] In one embodiment, the ends of the clips are chamfered or radiused or filleted or bevelled to enable a removal tool to be inserted between the clip and the member of the screen.

In one embodiment, a length of an opening in the screen is greater than a length of the clip or clips located in the opening to thereby enable a removal tool to be inserted between the clip and the member of the screen.

[0026] In a third aspect, the present invention provides a locking strip for use with the screen of the first aspect of the present invention and the clip rail of the second aspect of the present invention, the locking strip comprising a central downwardly extending protrusion, a first downwardly extending protrusion located to one side of the central downwardly extending protrusion and a second downwardly extending protrusion located to another side of the central downwardly extending protrusion.

[0027] In one embodiment, the central downwardly extending protrusion is located generally along a centreline of the locking strip.

[0028] In one embodiment, the first downwardly extending protrusion is spaced from the central downwardly extending protrusion and the second downwardly extending protrusion is spaced from the central downwardly extending protrusion.

[0029] In one embodiment of the locking strip, the central protrusion extends downwardly to a greater extent than the first and second downwardly extending protrusions. Other embodiments may have a central protrusion extending downwardly to the same extent as the first and second downwardly extending protrusions, or the first and second downwardly extending protrusions extending downwardly to a greater extent than the central protrusion.

[0030] In one embodiment, the locking strip has a width that is sufficient to span from an edge of the first screen to an edge of the second screen mounted adjacent to the first screen, when the screen is mounted to the screen deck. In one embodiment, the locking strip has a length that is essentially identical to the opposed edges of the first screen and the second screen. In this manner, the locking strip can completely cover the spaces between the opposed edges of first screen and the second screen. This prevents particulate material entering into that region and possibly causing damage to the edges of the screen and the clip rail.

[0031] In one embodiment, the central downwardly extending protrusion extends through the space between the first upstanding part and second upstanding part of the clip rail and abuts onto the members of the first screen and the second screen, and the first and second downwardly extending protrusions that are spaced to the side of the central protrusion come into contact with upper outer surfaces of the respective first and second upstanding parts of the clip rail and forces the first and second upwardly extending parts of clip rail to move towards each other. In one embodiment, the central downwardly extending protrusion of the locking strip has an enlargement and the enlargement is located below the second lateral projections of the upwardly extending parts of the clip rail. In one embodiment, the central downwardly extending protrusion has a neck that, in use, is located between the second lateral projections of the upwardly extending parts of the clip rail and a head region or enlarged region that, in use, is located below the second lateral projections of the upwardly extending parts of the clip rail. In this manner, the upper lateral projections of the clip rail hold the head or enlarged region of the locking strip in position. This is further facilitated by the first and second downwardly extending protrusions of the locking strip forcing the upper parts of the first and second upwardly extending parts of the clip rail towards each other, thereby reducing the space in which the neck of the central downwardly extending protrusion is located. In some embodiments, one or more clips may be placed or formed on the first and/or second downwardly extending protrusions to further assist in holding the locking strip in place.

[0032] In one embodiment, the central portion and the first and second downwardly extending portions extend parallel to a longitudinal axis of the locking strip. In one embodiment, the central portion and the first and second downwardly extending portions extend substantially along the length of the locking strip.

[0033] In one embodiment, the locking strip includes one or more recesses that are of complementary shape to one or more regions on the edge of the screen to thereby prevent creep of the locking strip relative to the screen during use. In one embodiment, the locking strip includes one or more protrusions that are of complementary shape to one or more regions on the edge of the screen to thereby prevent creep of the locking strip relative to the screen during use. In one embodiment, the one or more regions on the edge of the screen comprise the attachment regions that attach the elongate member to the screen.

[0034] In a fourth aspect, the present invention provides a screening apparatus having a screen deck, a clip rail as hereinbefore described attached to the screen deck, first and second screens as hereinbefore described positioned such that upper parts of the upwardly extending parts of the clip rail extend through the openings between the members and respective side edges of the screen, and a locking strip as hereinbefore described, the central downwardly extending portion of the locking strip extending downwardly into a space between the first and second upwardly extending parts of the clip rail.

[0035] In some embodiments, the first and second downwardly extending portions of the locking strip force the upper parts of the first and second upwardly extending portions of the clip rail towards each other to thereby hold the members of the screens in place and to also more securely hold the central downwardly extending portion of the locking strip in place.

[0036] The locking strip may have a hole, an eyelet, a recess, a slot or a hook protrusion in order to facilitate removal of the locking strip from the screen assembly.

[0037] Placement of the screening panels in accordance with the present invention onto the screening deck of the screening apparatus is easily achieved by mounting the clip rail to a stringer rail of the underlying screening deck/screen machine and simply pushing the screen panels into place over the clip rail, followed by pushing the locking strip into position. It is not necessary to use a hammer to properly fit the components onto the screening deck. Removal of the screening panel can be achieved by using a tool having a flat blade, hook or plate, such as a screwdriver or a lever, or using a tool having a hook. As a result, the screening panels are easy to fit and replace, thereby reducing the time taken to replace a screening panel and also reducing Occupational Health & Safety issues associated with replacing screening panels. In preferred embodiments, removal of the locking strip may be achieved by engaging a tool with a hole or a similar hook protrusion on the locking strip.

[0038] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0039] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0040] Various embodiments of the invention will be described with reference to the following drawings, in which:

[0041] Figure 1 shows a top view of a screen in accordance with an embodiment of the present invention;

[0042] Figure 2 shows a side view of the screen shown in figure 1 ;

[0043] Figure 3 shows an underneath view of the screen as shown in figure 1;

[0044] Figure 4 shows a perspective top view of the screen shown in figure 1 ;

[0045] Figure 5 shows a perspective view from underneath of the screen shown in figure 1 ; [0046] Figure 6 shows a perspective view of a clip rail in accordance with an embodiment of the present invention;

[0047] Figure 7 shows a top view of the clip rail shown in figure 6;

[0048] Figure 8 shows a side view of the clip rail shown in figure 6;

[0049] Figure 9 shows an end view of the clip rail shown in figure 6;

[0050] Figure 10 shows an expanded view of detail C of figure 6;

[0051] Figure 11 shows a top view of a locking strip in accordance with an embodiment of the present invention;

[0052] Figure 12 shows a side view of the locking strip shown in figure 11;

[0053] Figure 13 shows an end view of the locking strip shown in figure 11;

[0054] Figure 14 shows a perspective view, apart and in line for assembly, showing a clip rail, a screen and a locking strip in accordance with embodiments of the present invention ready for assembly together;

[0055] Figure 15 shows an end cross sectional view of the clip rail, two screens and the locking strip one assembled together;

[0056] Figure 16 is a perspective view of the assembly shown in figure 15;

[0057] Figure 17 is a perspective view of two screens assembled together;

[0058] Figure 18 is a side view of a removal tool for use with the present invention;

[0059] Figure 19 shows the removal tool of figure 18 being used to remove from the screen assembly; and

[0060] Figure 20 shows a perspective view of an alternativeremoval tool.

DESCRIPTION OF EMBODIMENTS

[0061] The skilled person will appreciate that the drawings have been shown for the purposes of illustrating preferred embodiments of the present invention. Therefore, it will be understood that the invention should not be considered to be limited solely to the features as shown in the attached drawings. [0062] In brief terms, an OEM screening apparatus or screening machine is provided that has a surface that, in use, forms the underlying screen deck. A stringer rail, which is generally a steel angle iron rail that forms part of the OEM's screening machine, is mounted to or forms part of the underlying screen deck of the screening machine. The clip rail is then connected to the stringer rail, typically by the use of bolts or studs and washers/nuts. The screens or screen panels are then pushed onto the clip rails and the locking strips and placed into position to lock the screen to screen panels down.

[0063] Figures 1 to 5 show various views of a screen 10 in accordance with an embodiment of the present invention. The screen 10 is in the form of a screening panel that is generally rectangular in shape and has a first set of opposed edges 12, 14 and a second set of opposed edges 16, 18. A plurality of screening apertures 20 are provided to enable particulate material sized smaller than the screening apertures to fall therethrough whilst particulate material larger than the screening apertures cannot pass through the screen. The screen 10 includes a plurality of ribs, some of which are numbered at 22, 24 and 26 and are most clearly shown in figure 5, with the plurality of ribs being located beneath the top surface of the screen 10 and providing additional strength to the screen 10. This construction is reasonably common in the art and need not be described further. The skilled person will also understand that the screen 10 will typically be made from a resilient and tough plastic material or an elastomeric material, such as polyurethane or rubber, so that it can absorb the impact of particulate material thereon. To provide increased strength to the screen, a metal or reinforced plastic frame (not shown in figures 1 to 5) may be enveloped within the plastic or elastomeric material. Again, this construction is common in the art and need not be described further.

[0064] The opposed edges 16, 18 are provided with respective member 28, 30. In the embodiment shown in the attached drawing, the members 28, 30 are integrally formed with the screen 10. However, in other embodiments, the members 28, 30 may be separate members that are subsequently attached to the screen 10. As can be seen from figures 2 and 4, the members 28, 30 have a lesser height than the edges 16, 18 at the top of the members 28, 30 is located below the open edges of opposed edges 16, 18. In the embodiment shown in the attached drawings, the lower edges of members 28, 30 are in the same plane as the lower edges of the screen 10. The lower edge of member 30 is provided with upwardly extending recesses 31, 33. These recesses allow a flat blade or a hook of removal tool to be inserted into those recesses to assist in levering up the screen in order to remove the screen from the screening apparatus. In an alternative embodiment, one or more recesses or slots could be formed in the side of the members 28, 30 such that a flat blade or a hook or a plate could be used to engage with those recesses to facilitate removal of the screen from the screen deck.

[0065] The member 28 is attached to the edge 16 of screen 10 at attachment regions 32, 34 and 36. Further, the member 28 is spaced from the edge 16. Accordingly, opening 38 is defined between edge 16, member 28 and attachment regions 32 and 34. Similarly, opening 40 is formed between edge 16, member 28 and attachment regions 34 and 36. A similar arrangement is present at the other end of the panel, where opening 48 is defined between edge 18, member 30 and attachment regions 42 and 44. Opening 50 is defined between edge 18, and the 30 and attachment regions 44 and 46. The openings 38, 40, 48 and 50 have an open bottom and an open top.

[0066] It will be appreciated that the attachment regions 32, 34, 36 and 42, 44, 46 are integrally formed with the screen 10. For example, the attachment regions may be formed as part of the moulding process that forms the panel 10, the attachment regions and the members 16, 18. Further, as best shown in figure 4, the attachment regions 42, 44, 46 have an upper edge that is located above the upper edge of the member 30, but located below the upper edge of screen 10. The attachment regions at the other end of the screen 10 are similar.

[0067] Figures 6 to 10 show various views of a clip rail 60 in accordance with an embodiment of the present invention. The clip rail 60 has a base portion 62. The base portion 62 comprises a central portion 64 and side skirt regions 68, 70 that extend downwardly and outwardly from the edges of the central portion 64. This is best shown in figure 9. The base portion 64 may have an elongate metal strip 70 that is enveloped within plastic material 72. The plastic material 72 also forms the side skirts 66, 68. A plurality of spaced attachment means, some of which are numbered at 74, extend downwardly from the underside of the base portion 62. The attachment means may be in the form of cylindrical members having a bore 76 formed therein. The cylindrical attachment means 74 can extend through appropriate openings in a stringer rail on the underlying screen deck of the screening apparatus and nuts, washers and bolts or other suitable fasteners can then be used to securely fastened the attachment means 74, and hence the clip rail 60, to the screen deck. Again, this method of attaching the clip rail to the underlying screen deck of the screening apparatus will be well understood.

[0068] The clip rail 60 is provided with a plurality of clips. Some of the clips are numbered at 78, 80, 82 and 84. As can be seen from figures 6 to 8, the clips are arranged in pairs, with clips 78, 80 forming a first pair and clips 82, 84 forming a second pair. Clip 78 is spaced

longitudinally from clip 80 and clip 82 is longitudinally spaced from clip 84. However, the longitudinal spacing between clips 78 and 80 is less than the longitudinal spacing between clips 80 and 82. This arrangement is repeated for all of the clips on the clip rail 60. As can also be seen from figures 6 to 8, the end clip 78 is spaced inwardly from the end of the base portion 62 of the clip rail 60. Similarly, the clip 85 at the opposite end of the clip rail 60 is also spaced inwardly from the end 86 of the clip rail 60.

[0069] Figure 9 shows a detailed and view of the clip 78. The clip 78 has a first upstanding part 88 and a second upstanding part 90. First upstanding part 88 and second upstanding part 90 may be considered to be the first clip arm and the second clip arm. First upstanding part 88 is laterally spaced from second upstanding part 90. The upstanding parts 88, 90 may be integrally formed with the base portion 64. An interconnecting web 92 is located between the first and second upstanding parts 88, 90. The upstanding parts 88, 90 of clip 78 are made from a resilient plastic material.

[0070] The first upstanding part 88 has a lower outer surface 94 that is spaced outwardly relative to an upper outer surface 96 of the first upstanding part. In other words, the upper surface 96 of the first upstanding part 88 is positioned closer to the centreline of the clip rail 60 then the lower outer surface 94. With reference to the second upstanding part 90, the outer surface thereof has a lower generally vertically extending wall 97, an inwardly inclined wall 98, a small generally vertical wall portion 99 and an inwardly extending wall 100. The profile of the outer surface of the first upstanding is essentially identical, but in mirror image.

[0071] The inner surface of first upstanding part 88 has a first lateral projection 102 that extends inwardly towards the second upstanding part 90 and a second lateral projection 104 that extends inwardly towards the second upstanding part 90. Similarly, the second upstanding part 90 has a first lateral projection 106 and a second lateral projection 108 that both extend inwardly towards the first upstanding part 88. The opposed lateral projections 102, 106 define a region 110 of reduced cross-sectional area. Similarly, the opposed lateral projections 104, 108 define a region of reduced cross-sectional area 112. A panel retention surface 114 is formed on the lateral projection 102. The profile of the inner surfaces of the respective first upstanding part 88 and second upstanding part 90 includes a lower region 116, the region 110 of reduced cross-section, an intermediate region 118 that has a larger cross-section than regions 110, 112 of reduced cross- section. The functioning of this particular shape or profile will be described in detail hereunder.

[0072] The inner ends of the upstanding portions have chamfered or bevelled ends, as best shown in figure 10, where a chamfer 120 is formed on the inner end. A similar chamfer is formed on the other ends of the clip arms. [0073] Figures 11 to 13 show various views of a locking strip 130 in accordance with an embodiment of the present invention. The locking strip 130 is of generally similar length to the clip rail 60. However, in other embodiments, locking strip 130 may be of a different length to the clip rail 60. The locking strip 130 has a metal strip 132 enveloped in a plastic casing, such as a durable polyurethane casing. This is best shown in figure 13. The locking strip 130 has an eyelet 136 to facilitate easier removal. For example, a hook may be placed into eyelet 136 and the hook pulled to remove the locking strip 130. The locking strip 130 also has a plurality of anti-creep slots or recesses, some of which are numbered at 138. The anti-creep slots or recesses 138 are sized and spaced so that they fit over the upper edges of the attachment regions 42, 44, 46 of the panel shown in figure 4. In this manner, relative movement of the locking strip along the side of the panel is prevented.

[0074] The cross-sectional shape of the locking strip 130 is shown in figure 13. As can be seen from figure 13, the locking strip 130 has a downwardly extending central portion 140, a first downwardly extending portion 142 located to one side of the central portion 140 and a second downwardly extending portion 144 located to the other side of central portion 140. As can be seen from figure 13, the central portion 140 extends downwardly further than the portions 142, 144.

[0075] The central downwardly extending portion 140 comprises a neck 146 and a head 148 located at the end of the neck 146. Outwardly extending regions 150 are located on the side of the upper part of the head and delineate the head 148 from the neck 146. The head 148 includes a tapered region defined by walls 152, 154 and a bottom 156.

[0076] As can also be seen from figure 13, the first and second downwardly extending portions 142, 144 are spaced from and to the side of the central portion 140. Each of the portions 142, 144 tend to taper downwardly. Radiused regions 158 interconnect the downwardly extending portions 142, 144 with the outer surface of the locking strip 130. This reduces stress concentrations in the vicinity of the locking strip near the outer parts of the downwardly extending portions 142, 144.

[0077] Assembly of the screen 10, the clip rail 60 and the locking strip 130 will now be described. Initially with reference to figure 14, the clip rail 60 is attached to a screen deck of a screening apparatus (not shown). It will be understood that a plurality of clip rails 130 are attached at the desired spacing on the screen deck. A panel 10 is then positioned such that the member 28 that is spaced from the edge 16 is positioned to be located inwardly of the first upstanding parts 88 of the clips 82, 84 and clips 78, 80. The first upstanding parts 88 of clips 82, 84 extend through the opening 38 defined between the edge 16, member 28 and attachment regions 32, 34. Similarly, the first upstanding parts 88 of clips 78, 80 extend through the opening 40 defined between the member 28, edge 16, attachment regions 34 and attachment region 36. Another screen is similarly arranged such that the second upstanding parts of clips 78, 80 and 82, 84 extend through the respective openings of that screen. The locking strip 130 is then positioned and pushed downwardly to engage with the upper parts of the clips and to lock the panels in place on the clip rail.

[0078] Figures 15 and 16 show cross-sectional and views and perspective views, respectively of the fully assembled screen assembly. In figure 15, a screen 10A is positioned such that first upwardly extending portion (or first clip arm) 88 extends through the opening defined by between the edge 16A and the member 28A. Similarly, screen 10B is positioned such that the second upstanding portion (or second clip arm) 90 extends through the opening defined between the member 30B and the edge 18B of the panel 10B. As a result, the members 28 A, 30B are positioned inside lower region 116 of the clips 78, 80. As can be seen from figures 15 and 16, the upper surfaces of the members 28A, 30B are in abutment with the panel retention surfaces 114 of the lateral projections 102, 106 of the clips. This assists in retaining the members 28A, 30B in position. As can also be seen from figures 15 and 16, spaces 160, 162 are formed between the edges 16A, 18B and the upper surfaces of first upstanding part 88 and second upstanding part 90.

[0079] In order to more securely lock the panels 10A, 10B in position the locking strip 130 is then pushed into place. As can be seen from figures 15 and 16, the head 148 of the central portion 140 comes into abutment with the top of the members 28A, 30B. The outwardly extending regions 150 of the head 148 are in abutment with the lower edges of lateral projections 104, 108 of the clips and the neck 146 of the central portion of the locking strip 130 extends through the space 112. Further, the first and second downwardly extending portions 142, 144 of the locking strip are pushed into the spaces 160, 162 and this acts to cause the upper part of the first upstanding part 88 and the second upstanding part 90 to be pushed inwardly so that it thereby more securely locks onto the head and neck of the central portion 140 of the locking strip 130. In this manner, the locking strip is securely held in position by the clips and the locking strip securely holds the panels in place.

[0080] Figure 17 shows a clip rail 60 having a plurality of screens 10A - 10G attached thereto, with the locking strip 130 being used to lock the screens in place. It is believed that the screens and locking strip will be able to be properly positioned by use of hand force alone, although in instances it may be useful to use a hammer or a rubber mallet if the ergonomics of the location of the screens permits. [0081] An advantage of the apparatus of the present invention is that it may be removed without requiring a hammer to drive a tool. Rather, a relatively simple lever-based tool may be used to remove the screens from the screen deck. An example of an appropriate tool is shown in figure 18, in which a tool 170 having a handle 172 and a shank 174 is provided. Shank 174 maybe in the form of a strip of metal having a hook 176. A spreader bar 178 is welded to the shank 174. Openings 180 are formed below torsion bars 184, 186 on the shank 174. A lever 188 has a handle 190 and an angled portion 192. A hook 194 is provided at the end of the angled portion 192. An arcuate rotation surface 196 is attached to an outer part of the lower end of the handle 190.

[0082] In order to remove a screen from the screen deck, a hook is engaged with the eyelet 136 of the locking strip 130 and the locking strip 130 is lifted using a hook to thereby separate and remove the locking strip 130 from the screen assembly. The shank of the tool 170 is then inserted into the space between the clip and the edge of the panel, with the hook 176 of the 174 of tool 170 being inserted in the open region defined by the chamfer 120 on the clips of the clip rail. The hook 176 can then be positioned underneath the member of the screen, as shown in figure 19. The lever 188 is position such that the hook 194 is located in opening 180. The lever is then rotated in a clockwise direction (as shown in figure 19). This causes the lever to rotate the member 28 of the screen 10 outwardly and upwardly, which also causes the upstanding part 88 of the clip to rotate outwardly, thereby widening spaces 110 and 112 and enabling the panel to be released from the clip.

[0083] In another embodiment, the hook of the tool may be able to move upwardly and outwardly, for example, by mounting the tool onto a threaded shank and rotating the shank by use of a socket or a power tool. This also allows the screen/screen panel to be easily removed. Figure 20 shows a perspective view of such a tool.

[0084] The tool 200 of figure 20 has a hollow housing 202 having a slot or opening 204 in one side. A hook 206 having a shank 208 is mounted to body 210 that is, in turn, mounted to a nut 212. A nut 212 is fixed inside body 210 and a shaft 214 that is threadable engaged with the threads of the nut 212 can rotate relative to the nut 212. Shaft 212 and nut 214 have complementary screw threads thereon. The tool 200 is also provided with a handle 218 and a foot 220, both of which are fixed to the housing 202.

[0085] The top of rotatable shaft 212 is provided with a rotation point. In particular, the top of shaft 212 has a universal connection 216 fitted thereto. Universal connection 216 has a socket drive 217 that can engage with a socket or power tool to cause the shaft 212 to rotate relative to the nut 214. This causes the nut 212 to move upwardly or downwardly along the shaft 214, depending upon the direction of rotation. As a result, the hook 206 also moves upwardly or downwardly relative to the housing 202 and the foot 220.

[0086] In order to remove a screen panel, the hook 206 is located underneath the edge of the panel and the foot 220 brought into contact with an adjacent panel or the underlying deck (or other structure). A socket or power tool rotates the socket drive 217 to cause the hook 206 to retract which lifts the edge of the screen panel and removes the screen panel.

[0087] Other ways of causing the extendable shaft 212 to extend or retract relative to the foot 220 could also be used, such as by use of a telescoping mechanism or by use of a lever mechanism or by use of a rotatable shaft threadably engeged inside a hollow shaft.

[0088] As a further alternative, a flat blade screwdriver can also be used to assist in removing the screen from the clip rail.

[0089] The present invention allows screens to be easily and securely mounted to a screening apparatus. The screens can be removed for repair or replacement without requiring use of a hammer to remove the screens. As a result, impact injuries caused to operating personnel by use of hammers are likely to be reduced. The provision of the screens having openings between edges of the screens and the members of the screens enables clip arms to be inserted through the openings. Locking strips can then be used to securely lock the screens, the clip arms and the locking strips securely in place. Desirably, the locking strips extend from the edge of one screen to the edge of another screen that is being held in place by the clips to thereby cover any openings and prevent ingress of particulate material between the panels and the clips. In preferred embodiments of the present invention, the clips are formed as a number of spaced pairs of clips, with each clip having two opposed arms. This can provide sufficient space between each clip in the pair of clips to enable the removal tool to be inserted between the clips to enable the panel to be removed. The panels may be provided with recesses formed in the lower surface of the members to enable the removal to be inserted between the lower edge of the members and the clamping rail.

[0090] In the present specification and claims (if any), the word‘comprising’ and its derivatives including‘comprises’ and‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0091] Reference throughout this specification to‘one embodiment’ or‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases‘in one embodiment’ or‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment.

Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0092] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims (1)

1. 1. A screen for use with a screening apparatus, the screen being adapted to be replaceably mounted to the screening apparatus, the screen comprising a panel having a plurality of screening apertures, the panel having a first pair of opposed edges and a second pair of opposed edges, the first pair of opposed edges having a member, each member being attached to its respective edge and being spaced from its respective edge such that at least one opening is defined between each member and its respective edge, the opening having an open top and an open bottom.

   2. A screen as claimed in claim 1 wherein each member comprises an elongate member.

   3. A screen as claimed in claim 2 wherein each elongate member extends along a length of its respective edge.

   4. A screen as claimed in any one of claims 1 to 3 wherein the opening is adapted to receive an upwardly extending part of a clip rail attached to a screen deck of the screening apparatus.

   5. A screen as claimed in claim 4 wherein the opening is adapted to enable the upwardly extending part of the clip rail to pass through the bottom of the opening and extend through top of the opening such that a portion of the upwardly extending part of the clip rail is located above an upper part of the elongate member.

   6. A screen as claimed in any one of claims 2 to 5 wherein each elongate member is attached to the respective side edge at a plurality of points or regions whereby a plurality of openings are defined between the elongate member and its respective edge, with each opening being defined by the elongate member, the respective edge, and adjacent attachment points or regions.

   7. A screen as claimed in any one of claims 2 to 6 wherein the elongate members are integrally formed with the panel, or the elongate members are formed as separate items and are attached to the panel.

   8. A screen as claimed in any one of claims 2 to 7 wherein a lower edge of the elongate member is positioned above the lower edge of the screen or a lower edge of the elongate member includes an upwardly extending recess, or one or more recesses or slots are formed in the side of the elongate member.

   9. A screen as claimed in any one of preceding claims wherein the screen is provided with regions extending outwardly from the opposed edges of the screen, the regions engaging with corresponding or complementary shaped regions on a locking strip to thereby prevent creep of the locking strip along the screen during use.

   10. A screen as claimed in any one of the preceding claims wherein the panel is made from a plastic material or rubber and the panel include a metal frame.

   11. A clip rail for attachment to an underlying screen deck of a screening apparatus, the clip rail adapted to facilitate attachment of a screen as claimed in any one of the preceding claims to the screening apparatus, the clip rail comprising a first upstanding part and a second upstanding part, the first upstanding part having an upper portion that is spaced from an upper portion of the second upstanding part, the first upstanding part extending through the opening of a first screen, the second upstanding part extending through the opening of a second screen.

   12. A clip rail as claimed in claim 11 wherein the first upstanding part and the second upstanding part are resilient, or resilient and flexible.

   13. A clip rail as claimed in claim 11 or claim 12 wherein the upper portion of the first upstanding part is spaced from the upper portion of the second upstanding part in a direction across a width of the clip rail.

   14. A clip rail as claimed in any one of claims 11 to 13 wherein the clip rail comprises a plurality of clips, with the clips being spaced from each other in a direction along a length of the clip rail, each clip comprising the first upstanding part and the second upstanding part, wherein in use the first upstanding part of each of the clips is received in an opening of the first screen and the second upstanding part of each of the clips is received in an opening of the second screen.

   15. A clip rail as claimed in any one of claims 11 to 14 wherein the first upstanding part has a first lateral projection above a lower part of the first upstanding part and a second lateral projection spaced above the first lateral projection, and the second upstanding part has first lateral projection spaced above the lower part of the second upstanding portion and a second lateral projection spaced above the first lateral projection, the lateral projections of the first upstanding part facing the lateral projections of the second upstanding part.

   16. A clip rail as claimed in claim 15 wherein the first lateral projections are opposed to each other and form a region of reduced space between the first upstanding part and the second upstanding part and the second lateral projections are opposed to each other and form a region of reduced space between the first upstanding part and the second upstanding part such that, in use, the elongate members of the first screen and of the second screen are positioned such that the elongate members are positioned below the first lateral projections and a region of a locking bar or locking strip is positioned such that it is located below the second lateral projections and above the elongate members of the first screen and the second screen, when the first screen and the second screen mounted to the clip rail.

   17. A clip rail as claimed in any one of claims 11 to 16 wherein the clip rail comprises a base portion, with the upstanding portions extending upwardly relative to the base portion.

   18. A clip rail as claimed in claim 17 wherein the base portion includes attachment regions or attachment means for attaching the clip rail to the screen deck.

   19. A clip rail as claimed in claim 18 wherein the attachment regions or the attachment means are located underneath the clip rail.

   20. A clip rail as claimed in any one of claims 11 to 19 wherein the upstanding portions are spaced inwardly from each end of the base portion of the clip rail.

   21. A clip rail as claimed in any one of claims 11 to 20 wherein the first upstanding part and the second upstanding part have an outer surface at which a lower region is further spaced from a longitudinal axis of the clip rail than an upper region is spaced from the longitudinal axis of the clip rail.

   22. A clip rail as claimed in any one of claims 11 to 21 wherein ends of the clips are chamfered or bevelled to enable a removal tool to be inserted between the clip and the member of the screen.

   23. A clip rail as claimed in claim 22 wherein a length of an opening in the screen is greater than a length of the clip or clips located in the opening to thereby enable a removal tool to be inserted between the clip and the member of the screen.

   24. A locking strip for use with the screen as claimed in any one of claims 1 to 10 and the clip rail as claimed in any one of claims 11 to 23, the locking strip comprising a central downwardly extending protrusion, a first downwardly extending protrusion located to one side of the central downwardly extending protrusion and a second downwardly extending protrusion located to another side of the central downwardly extending protrusion.

   25. A locking strip as claimed in claim 24 wherein the central downwardly extending protrusion is located generally along a centreline of the locking strip.

   26. A locking strip as claimed in claim 24 or claim 25 wherein the first downwardly extending protrusion is spaced from the central downwardly extending protrusion and the second downwardly extending protmsion is spaced from the central downwardly extending protrusion.

   27. A locking strip as claimed in any one of claims 24 to 26 wherein the central protrusion extends downwardly to a greater extent than the first and second downwardly extending protrusions, or the central protrusion extends downwardly to the same extent as the first and second downwardly extending protrusions, or the first and second downwardly extending protrusions extending downwardly to a greater extent than the central protrusion.

   28. A locking strip as claimed in any one of claims 24 to wherein the locking strip has a width that is sufficient to span from an edge of the first screen to an edge of the second screen mounted adjacent to the first screen, when the screen is mounted to the screen deck.

   29. A locking strip as claimed in claim 28 wherein the locking strip has a length that is essentially identical to the opposed edges of the first screen and the second screen such that the locking strip can completely cover the spaces between the opposed edges of first screen and the second screen.

   30. A locking strip as claimed in any one of claims 24 to 29 wherein the central downwardly extending protrusion extends through the space between the first upstanding part and second upstanding part of the clip rail and abuts onto the members of the first screen and the second screen, and the first and second downwardly extending protmsions that are spaced to the side of the central protrusion come into contact with upper outer surfaces of the respective first and second upstanding parts of the clip rail and forces the first and second upwardly extending parts of clip rail to move towards each other.

   31. A locking strip as claimed in any one of claims 24 to 30 wherein the central downwardly extending protrusion of the locking strip has an enlargement and the enlargement is located below the second lateral projections of the upwardly extending parts of the clip rail.

   32. A locking strip as claimed in claim 31 wherein the central downwardly extending protrusion has a neck that, in use, is located between the second lateral projections of the upwardly extending parts of the clip rail and a head region or enlarged region that, in use, is located below the second lateral projections of the upwardly extending parts of the clip rail whereby the upper lateral projections of the clip rail hold the head or enlarged region of the locking strip in position.

   33. A locking strip as claimed in any one of claims 24 to 32 wherein one or more clips are placed or formed on the first and/or second downwardly extending protrusions to further assist in holding the locking strip in place.

   35. A locking strip as claimed in any one of claims 24 to 33 wherein the central portion and the first and second downwardly extending portions extend parallel to a longitudinal axis of the locking strip.

   36. A locking strip as claimed in any one of claims 24 to 35 wherein the central portion and the first and second downwardly extending portions extend substantially along the length of the locking strip.

   37. A locking strip as claimed in any one of claims 24 to 36 wherein the locking strip includes one or more recesses that are of complementary shape to one or more regions on the edge of the screen to thereby prevent creep of the locking strip relative to the screen during use.

   38. A locking strip as claimed in any one of claims 24 to 36 wherein the locking strip includes one or more protrusions that are of complementary shape to one or more regions on the edge of the screen to thereby prevent creep of the locking strip relative to the screen during use.

   39. A locking strip as claimed in claim 37 or claim 38 wherein the one or more regions on the edge of the screen comprise the attachment regions that attach the elongate member to the screen.

   40. A screening apparatus having an underlying screen deck, a clip rail as claimed in any one of claims 11 to 23 attached to the underlying screen deck or to a stringer rail of the underlying screen deck, first and second screens as claimed in any one of claims 1 to 10 positioned such that upper parts of the upwardly extending parts of the clip rail extend through the openings between the members and respective side edges of the screen, and a locking strip as claimed in any one of claims 24 to 39, the central downwardly extending portion of the locking strip extending downwardly into a space between the first and second upwardly extending parts of the clip rail.

   41. A screening apparatus as claimed in claim 40 wherein the first and second downwardly extending portions of the locking strip force the upper parts of the first and second upwardly extending portions of the clip rail towards each other to thereby hold the members of the screens in place and to also more securely hold the central downwardly extending portion of the locking strip in place.

   42. A screening apparatus as claimed in claim 40 or claim 41 wherein the locking strip has a hole, an eyelet or a hook protrusion in order to facilitate removal of the locking strip from the screen assembly.