Screening panel and method of fixing

Abstract

A screen panel 15 for mounting to a vibratory screening apparatus that includes a plurality of beams 11 to which screen panels 15 can be mounted. The screen panel 15 comprises a square or rectangular frame 21 including a pair of spaced apart and parallel side frame members 25 and a pair of spaced apart and parallel end frame members 38 connected to the side frame members 25. The frame 21 defines an upper edge and the side and end frame members define a square or rectangular outwardly facing surface. The frame 21 is connectable to a pair of adjacent beams 11 by connectors 20 that connect with the outwardly facing surface of the side frame members 25. The screen panel 15 also comprises a square or rectangular screen 22 connected to the frame 21 which extends over the upper edge of the frame 21 and forms a square or rectangular skirt 33, 36. The skirt 33, 36 overlies the outwardly facing surface of the frame 21 and connects to each of the side and end frame members along the outwardly facing surface to connect the screen 22 to the frame 21. The connection between skirt 36 and the outwardly facing surface of the side frame members 25 is made closer to the upper edge of the frame than where the connection between the connectors 20 and the outwardly facing surface of the side members 25 of the frame 21 is made.

Claims

1. A screen panel for mounting to a vibratory screening apparatus for the purpose of screening, separating or grading materials, the screening apparatus including a plurality of spaced apart, substantially parallel elongate beams to which the screen panel is to be mounted, the screen panel comprising: i. a square or rectangular frame which includes a pair of spaced apart and parallel side frame members and a pair of spaced apart and parallel end frame members connected to the side members, the frame defining a square or rectangular upper edge and the side and end frame members defining a square or rectangular outwardly facing surface, the frame being connectable to a pair of adjacent elongate beams of a vibratory screening apparatus by connectors that connect with the outwardly facing surface of the side frame members, ii. a square or rectangular screen which is connected to the frame, the screen extending over the upper edge of the frame and forming a square or rectangular skirt which overlies the outwardly facing surface of the frame and which connects to each of the side and end frame members along the outwardly facing surface to connect the screen to the frame, iii. the connection between skirt of the screen and the outwardly facing surface of the side frame members of the frame being made closer to the upper edge of the frame than where the connection between the connectors and the outwardly facing surface of the side members of the frame is made.

2. A screen panel according to claim 1, the skirt being defined by a pair of spaced apart and parallel side skirt members and a pair of spaced apart and parallel end skirt members, the outwardly facing surface of the frame having a channel formed in each of the side and end frame members and the side and end skirt members including an inwardly extending projection for receipt within the channels of the side and end frame members.

3. A screen panel according to claim 2, the channels formed in the side frame members being of a greater depth than the channels formed in the end frame members, whereby the channels formed in the side frame members accept the inwardly extending projections of the side skirt members as well as connectors for connecting the frame to the adjacent elongate beams of the screening apparatus.

4. A screen panel according to claim 3, the channels formed in the end frame members having a base and a bearing surface extending from the base for bearing engagement with the projection of the end skirt members, the base and the bearing surface being disposed substantially perpendicular to each other and the bearing surface being substantially planar and perpendicular to the general plane of the end frame members.

5. A screen panel according to claim 4, the projections of the end skirt members including a planer bearing surface for engagement with the planar bearing surface of the channels of the end frame members.

6. A screen panel according to claim 3, the channels of the end frame members being sized to closely receive the projections of the end skirt members.

7. A screen panel according to claim 1, wherein the skirt includes at least one discontinuity to create at least one gap in the skirt.

8. A screen panel according to claim 7, wherein a pair of gaps is formed at diametrically opposed corners of the square or rectangular skirt.

9. A screen panel according to claim 7, wherein four gaps are formed at each corner of the square or rectangular skirt.

10. A screen panel according to claim 9, wherein the four gaps are formed by opposite ends of the side skirt members extending close to but being spaced from adjacent opposite ends of the end skirt members.

11. A screen panel according to claim 2, the projections of the end skirt members extending across the end skirt members from inboard of each end of the end skirt members.

12. A screen panel according to claim 2, the projections of the side skirt members extending across the side skirt members from each of the ends of the side skirt members.

13. A screen panel according to claim 1, the frame including a centre member that extends across the frame between opposite end or side walls and the screen including a channel within which the centre member is disposed, the walls of the channel being a close fit against the side walls of centre member but the channel being movable relative to the centre member upon vibration of the screen panel.

14. A screen panel according to claim 1, the screen including inner walls inboard of the skirt that are in spaced apart facing relationship with the skirt to define a channel for receipt of side frame members and the end frame members of the frame.

15. A screen panel according to claim 14, the inner walls forming a generally square or rectangular shape inboard of the skirt.

16. A screen panel according to claim 14, the inner walls forming a pair of adjacent square or rectangular walls which form a channel between them for receipt of the centre member.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In order that the invention may be more fully understood, some embodiments will now be described with reference to the figures in which:

(2) FIG. 1 illustrates a portion of a screening deck according to one embodiment of the invention.

(3) FIG. 2 is an exploded view of a screen panel according to one embodiment of the invention.

(4) FIG. 3 is a plan view of a frame of a screening panel according to one embodiment of the invention.

(5) FIG. 4 is a plan view of the screen of a screen panel according to one embodiment of the invention.

(6) FIG. 5 is a cross-sectional view through A-A of FIG. 4.

(7) FIG. 6 is a cross-sectional view through B-B of FIG. 4.

(8) FIG. 7 is an underneath isomeric view of the screen of a screen panel according to one embodiment of the invention.

(9) FIG. 8 is a top isometric view of a screen panel according to one embodiment of the present invention, connected to a screen deck.

DETAILED DESCRIPTION

(10) With reference to FIG. 1, a portion of a screening deck and subframe 10 of a vibratory machine is illustrated, comprising a plurality of elongate, longitudinal beams 11 each of which is formed from an angle of steel having a vertical portion 12 and a horizontal portion 13 disposed substantially at right angles. While the beams 11 extend in the longitudinal direction of the vibratory machine, the beams can equally extend perpendicularly to the longitudinal direction of the vibratory machine and the invention applies to that form of vibratory machine as well. The beams 11 can be of any length, such as increasing from 4 to 28 in 2 increments. The width dimensions likewise can be of any length, such as increasing from 2 to 14 in 2 increments.

(11) The deck and subframe 10 illustrated in FIG. 1 is a portion of a vibratory machine only and does not show the side edge beams that define the edge of the screening deck. The portion of the deck and subframe that is shown in FIG. 1 is sufficient however to describe the invention. Six beams 11 are illustrated in FIG. 1. In current machinery, the beams 11 are often spaced an imperial foot apart thus requiring nine beams for an 8 width.

(12) The beams 11 extend parallel to one another and support screen panels 15 on the upper face of the short portion 13 of each beam 11. The panels illustrated in FIG. 1 can be of any suitable size, but a common size is an imperial square foot (304.8 mm304.8 mm). However, alternative sizes of panels can be employed, such as 12 (or 304.8 mm609.6 mm).

(13) As indicated above, the screening deck and subframe is one part of the overall vibratory machinery. The screening deck is supported on a frame and is connected to a vibration generator. The vibration that is generated is significant and requires the panels 15 to be securely fixed to the beams 11. The panels are also subject to wear over time and even though the fixing of the panels to the beams is required to be secure, the preference is also that the panels be easily releasable to facilitate quick and easy replacement.

(14) The panels 15 include a plurality of openings through the top or screening surface thereof for screening product such as mining ore. The openings in the panel 15 can vary from large to very small depending on the size of the screened material which is to be produced. Indeed in some forms of the invention, the panel is completely open rather than having a plurality of openings. That is, the top of the panels 15 are formed to be fully open, with the exception that in some forms, the frame of the panel will include a stiffening bar extending across the panel (referred to herein as a centre member, usually midway between opposite ends or sides of the panel (this is seen in FIG. 3).

(15) Typically, an ore is fed onto one end of the screening deck 10 and a vibrating arrangement vibrates the deck 10 tending to shift the ore from one end to the other, with some of the ore passing through the openings of the panels 15 as it travels over the deck. Ore which does not pass through openings in the panels 15 is collected or transferred at the trailing end of the deck 10 opposite to the feeding end and can be retreated, such as re-crushed, or it can be used for other purposes or discarded.

(16) FIG. 1 shows several portions on the screening deck 10 that do not have panels installed. These vacant portions illustrate that the panels 15 can be removed when they have become worn or otherwise damaged. The portion of the screening deck 10 marked R1 shows four missing panels, but otherwise illustrates fixing rails 20 to which panels 15 are attached. The fixing rails 20 are fixed to the upper surface of the horizontal portion 13 of the beams 11 and more detail on the construction of the fixing rails 20 and their connection to the beams 11 can be found in Applicant's Australian Patent No. 2012201297.

(17) The screening deck 10 includes panels 15 shown in close proximity to each other. The preference is that the panels 15 actually make contact along their edges so that there are no gaps between the panels when they are fitted. Any gaps between adjacent panels 15 can provide an undesirable pathway for the flow of material being screened. In some prior art arrangements, a cover strip has been applied between adjacent panels to overlie the junction at the upper surface of adjacent panels to cover any gaps between them. Applicant's Australian Patent No. 2012201297 provides adjustment for the panels 15 as they are fitted to the screen deck in order to achieve a close fit between the panels

(18) The panels 15 of the screening deck 10 have a particular construction that is unique in relation to prior art panels. FIG. 2 is an exploded view of a screen panel 15 of the kind illustrated in FIG. 1. The screen panel 15 includes a frame 21 and a screen 22. The screen 22 includes a plurality of screening openings through a screening surface for screening mining ores and the like. The invention is not limited to any particular size of opening and in fact, the screen could be completely open to maximise the size of the material that can fall through the screening deck 10.

(19) The frame 21 is shown in plan view in FIG. 3 and shows the frame 21 as having a square external periphery 23 (which measures an imperial square foot or approximately 929 cm.sup.2) and a centre member 24 that extends between opposite side members 25 of the periphery 23. The centre member 24 adds stiffness to the screen panel 15. The section of the screen 22 that overlies the centre member 24 has no openings as the centre member 24 would interfere with the passage of screened media through them if they were provided.

(20) The frame 21 and the screen 22 have a construction that allows interconnection between them. Some of that interconnecting construction can be seen in FIGS. 2 and 3, but a better illustration is made in FIGS. 4 to 6 which shows the frame 21 and the screen 22 connected together in plan and cross-sectional views.

(21) With reference to FIG. 5, the frame 21 includes an outwardly opening elongate recess or channel 26 defined between upper and lower flanges 27 and 28. The screen 22 includes a skirt 36 that extends over the upper flange 27 and to overlie the channel 26. The skirt 36 includes an inwardly depending projection 29 that extends into the channel 26.

(22) A similar arrangement is repeated through the cross-section of FIG. 6 in which the frame 21 includes an outwardly opening elongate recess or channel 30 defined between upper and lower flanges 31 and 32. The screen 22 includes a skirt 33 that extends over the upper flange 31 and to overlie the channel 30. The skirt 33 includes an inwardly depending projection 34 that extends into the channel 30.

(23) Returning to FIG. 2, the respective skirts 33 and 36 can be seen depending from the top surface 35 of the screen 22. Each skirt 33 and 36 can connect with the frame 21 as described above. The respective skirts 33 and 36 represent front and rear skirts (33) and side skirts (36) as the screen 22 is oriented on the screening deck 10 of FIG. 1. The front and rear skirts 33 extend almost fully across the screen 22, while the side skirts 36 extend to a position which is spaced slightly from connection with the skirts 33. This is also seen in FIG. 7 which is an underneath view of the screen 22. In that figure, it can be seen that inner walls 40 and 41 form adjacent or side by side rectangular walls which are spaced inwardly from the skirts 33 and 36 to define channels for receipt of the periphery 23 of the frame 21 and to further define a channel 42 to accept the centre member 24 of the frame. See FIG. 6 which shows the periphery 23 of the frame 21 and the centre member 24 captured within the channels formed between the walls 40 and 41. The fit between the screen 22 and the frame 21 is to be a snug or light fit, not a friction fit. As described earlier, oscillation of the surface of the screen 22 is desirable and a close but not tight fit between the channel 42 and the centre member 24 allows this. The screen 22 is held to the frame 21 by cooperation between the projections 29 and 34 within the channels 26 and 30 rather than by friction engagement between the channels into which the frame 21 is fitted.

(24) The channels into which the frame 21 is received advantageously provide several advantages already discussed above. One major advantage is that the close fit of the frame 21 within the channel between the skirts 33 and 36 and the walls 40 and 41 more securely connect the screen 22 to the frame 21. This arises because capturing the frame 21 in a channel reduces the available flex of the screen 22 at the edges of the screen 22 and reduced flex at the edges means that the screen is less likely to disconnect from the frame 21. However, oscillation of the screen inboard of the edges is not affected.

(25) Also, capturing the frame in a channel reduces the likelihood of fines or coarse ore becoming trapped between the frame and the facing surface of the screen as described earlier. The channels thus effectively act as shedders to shed fines or coarse ore away from the frame 21.

(26) The gap G (see FIG. 2) is an important aspect of the screen panel 15, as it facilitates easier connection and disconnection of the screen 22 from the frame 21. The gap G allows each of the skirts 33 and 36 to flex outwardly to allow the respective projections 29 and 34 to ride over the upper flanges 27 and 31 of the frame 21 and to thereafter enter the respective channels 26 and 30 and thus to fix the screen 22 to the frame 21.

(27) The gap G also allows a tool to be inserted beneath one of the skirts 33 and 36 to lift them away from the frame to remove the screen 22 from the frame 21.

(28) Despite that the gap G provides advantages as discussed above, the invention extends to screens that do not have a gap, or that have a gap at a different position. Screens that do not have a gap could fit more tightly on the frame 21, but be more difficult to fit and remove. Screens that have a gap at a different position than at the corners of the screen 22 could have a gap inboard of the ends of one or more of the skirts 33 and 36, such as towards the middle of the skirts. Only one of the skirts, or one pair of skirts might include a gap. For example, two gaps might be provided at diametrically opposed corners of the screen and no gaps at the other corners.

(29) Moreover, FIG. 2 illustrates that the channel 30 into which the projection 34 (see FIG. 6) of the skirt 33 enters does not extend fully across the end wall 38. Rather, the channel 30 terminates just prior to each end of the end wall 38. This provides tooling advantages for post moulding part dress up.

(30) In a similar manner, the channels 26 also terminate within the length of the side walls 25, but this is to ensure proper connection with the fixing rails 20 to fix the screen panels to the screening deck. As seen in FIG. 8, the fixing rails 20 engage within the channels 26 below the bottom of the skirt 36 of the screen 22 and the ends of the fixing rails 20 abut against the facing surfaces of the respective channels 26 to form a close fit within the channels 26. The space for receipt of the fixing rails 20 below the bottom of the skirt 36 can be seen in FIG. 5. This arrangement is more fully illustrated in Applicant's Patent No. 2012201297.

(31) It can also be seen in FIG. 2 that the channel 26 is formed in a recessed portion 43 between end walls 44. The skirt 36 is received closely within the recess 43.

(32) FIG. 8 also illustrates the use of shedders 45 between the horizontal portions 13 of the beams 11 of the screening deck 10 and the underneath of the screen panel 15 and the fixing rails 20 to prevent or minimise the ingress of screened media between the screen panel 15 and the fixing rails 20 and the horizontal portions 13 of the beams 11.

(33) The illustrated embodiments have been described in relation to a screening deck 10 that includes beams 11 of 90 angle, however it is to be noted that the invention can equally apply to screening decks of other construction, such as that disclosed in Applicant's Patent No. 2012211453 and as particularly shown in FIG. 2 of that application. Such a construction is known in the industry as a pipe-top construction.

(34) The illustrated embodiment also shows that each of the skirts 33 and 36 include a respective projection 29, 34 for entry into a respective channel 26, 30 of the frame 21. It must be appreciated that the invention extends to arrangements in which the projections extend from the frame and the skirts of the screen include the channels into which the projections extend.

(35) Throughout the description and claims of this specification the word comprise and variations of that word, such as comprises and comprising, are not intended to exclude other additives, components, integers or steps.