AU2003204125A1

AU2003204125A1 - Ore Screening Panel Fixing System

Info

Publication number: AU2003204125A1
Application number: AU2003204125A
Authority: AU
Inventors: Jeff Zubovich
Original assignee: Screenex Australia Pty Ltd
Current assignee: Sandvik Rock Processing Australia Pty Ltd
Priority date: 2002-03-21
Filing date: 2003-05-12
Publication date: 2003-10-16
Anticipated expiration: 2023-03-20
Also published as: AU2003204125B2

Description

AUSTRALIA

Patents Act

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: 20032..

Divisional of 2003201378 filed 20-03-2003 Lodgement Date: 12 t h May 2003 Nominated Patentee: Screenex Australia Pty Ltd Invention Title: Ore Screening Panel Fixing System The following statement is a full description of this invention, including the best method of performing it known to the applicant.

Ore Screening Panel Fixing System This invention relates to improvements in ore screening panels used in the separation and grading of materials in the mining and quarrying industries.

Background to the invention Australian patent 482212 proposed a modular screening panel system for ore screening decks which is now widely used by the mining industry and replaced io the earlier screening cloths, and large wire screening frames. The screening panels were all of the same size [eg. 300mm] and made of reinforced polyurethane. The panels are adapted to be secured to an underlying support frame using dependent spigots which are a force fit into corresponding apertures in the support frame. Patent 517319 provided an alternative method of securing the panels to the frame using a pin expanded fastening concept.

The Australian patent 556953 disclosed the use of a hold down bar which abutted the edge flanges on the panels and had spigots passing through apertures in the edge flanges and into apertures in the underlying support frame.

Australian patent 700843 disclosed a two part hold down bar the first being bolted to the frame and the second being a snap fit into the first part.

Australian patent 559443 improved on this concept by providing a channeled bar which could be bolted to the underlying support frame. The panels had dependent flanges which were a force fit into the channel of the bar. A pair of abutting panels each provided flanges to fit into one channel. Together two abutting edge flanges provided a shape complementary to the cross sectional shape of the channel.

Patent 627919 discloses a modification of that arrangement but still relying on the force fit of the dependent flange or skirt on the edge of the panel, into the channel of the hold down bar. Australian patent 742060 and application 17523/00 are improvements in the dependent flange and channel shaped hold own bar concept.

All of these attachment systems encroach on the margins of the panel and restrict the available screening area of the screening surface.

It is an object of this invention to provide an alternative means of fastening screening panels which enables them to be easily installed and replaced.

It is a further object of this invention to increase available open area of the screening panel.

Brief description of the invention The present invention provides a mining screening assembly which includes a) a plurality of screening panels b) one or more hold down bars adapted to secure edge portions of said screening panels c) a support frame wherein the hold down bars are secured to the support frame by a fasteners that extend upwardly into the lower edge of the hold down bars and the hold down bars are of narrow cross section to increase the available open area of the screening panel.

By securing the hold down bar from underneath the bolt is located below the frame and is therefore protected from abrasion and dirt build up when the bolt is above the frame, usually in the channel of the channel shaped hold down bars or above the screening surface of the panel.

Preferably the hold down bar is T or I shaped so that the edges of the panels fit into the recess formed on either side of the central web of the hold down bar and the frame or the widened base of the hold down bar. In contrast to the prior art the screening panels do not require elaborate edge flange designs to snap fit into the hold down bar.

The hold down bar of this invention includes a) a web having a longitudinal dimension, a vertical dimension complementary to the thickness of a screening panel and a web thickness to provide upper and lower edges to said bar b) the lower longitudinal edge of said web being adapted to seat on a frame member of a screening machine and incorporating vertically extending recesses for receiving fastening means adapted to fasten the hold down bar to said frame c) the upper longitudinal edge having a laterally extending flange adapted to bear down on the edge surface of an ore screening panel.

The hold down bar may seat on a frame cover strip designed to protect the frame from abrasion or alternatively the bar may have the strip moulded into its base. In order to facilitate removal of screening panels the upper flange may include vertical slots which allow a lever or screwdriver access to the edge of the panel to force it past the flange of the hold down bar. The hold down bar is conveniently made from the same class of materials as the screening panels. Hard Rubber or polyurethane of suitable hardness is preferred. The holddown bar is reinforced by the inclusion of a metal, preferably steel, bar in the base of the hold down bar and this reinforcing bar incorporates the fastening recesses preferably screw threaded holes to receive a fastening bolt. The web of the hold down bar may incorporate additional recesses or ribs to engage complementary ribs or recesses respectively of the edges of the screen panel abutting the web.

In another aspect, this invention is also applicable to use in multi-tier screening decks particular those having two layers as described in Australian patents 601052 and 741062.

In this aspect the present invention provides a screening system which includes a) a support frame b) a first lower screening deck consisting of an array of screening panels c) a second upper screening deck consisting of an array of screening panels d) a hold down panel mounted on said support frame by fasteners that extend upwardly into the lower edge of the hold down bars and the edges of the screening panels are adapted to seat in recesses in the vertically extending face of the hold down panel e) each face of the hold down panel having two recesses vertically spaced apart to support the panels of the upper and lower decks.

This arrangement simplifies the design of the panels and the spacer panel which secures and spaces apart the panels of each deck.

The space panel includes a) a web having a longitudinal dimension, a vertical dimension complementary to the thickness of a screening panel and a web thickness to provide upper and lower edges to said bar b) the lower longitudinal edge of said web being adapted to seat on a frame member of a screening machine and incorporating vertically extending recesses for receiving fastening means adapted to fasten the hold down bar to said frame c) said web having a first laterally extending flange adapted to bear down on the upper edge surface of the screening panels of the lower deck d) the upper longitudinal edge of said web having a second laterally extending flange adapted to bear down on the edge surface of the screening panels of the upper deck e) said web having a third laterally projecting flange or rib adapted to provide a seat for the lower edge surface of the screening panels of the upper deck.

The web may be thickened between the first and third flanges or ribs.

Detailed description of the invention.

Preferred embodiments of the invention will be described with reference to the drawings in which: Figure 1 is an isometric view of a detail of a single level panel assembly; Figure 2 is a plan view of the holddown bar of figure 1; Figures 3 A and 3 B are two sectional views along the lines A-A and B-B respectively of figure 2; Figure 4 is a plan view of a screen deck using using the hold down bars of figure 1; Figure 5 is an side view of the deck shown in figure 4 Figure 6 is an end view of a two tier hold down panel and frame according to this invention; Figure 7 is a detail perspective of a detail of a screen deck using the panel of figure 6; Figure 8 is a cross sectional view of a further embodiment of the invention; Figure 9 is a cross sectional view of a modified version of the embodiment of figure 8.

As shown in figures I to 5 the screen deck [figure 4] consists of an array of rectangular screening panels 11 extending lengthwise between frame members 13 and being secured in place by hold down bars 20 to the support flanges 14 of the frame members 13. The upper flanges 22 of the hold down bars 20 bear down on the edge surface of the ends of the panels 11. The nut 17 on the shaft 16 secures the hold down bar 20 to the frame flange 14.

The hold down bars 20 as shown, are long enough to extend across four screening panels 13 and are secured to the frame flanges 14 by bolts 17 mounted on the screw threaded shaft 16 which extend up into the body 23 of the bars 20. The screw threaded shafts 16 screw into complementary threaded tubular reinforcements 26 embedded in the body 23 of the hold down bars 20. To protect the frame flanges 14 from abrasive material being screened, cover strips 28 are placed between the panels 11 and the frame flange 14. The cover strips 28 may be integrally moulded with the hold down bars 20. The preferred material is polyurethane similar to the material used for the panels 11. The cover strips 28 incorporate a washer 27 which abuts the shaft 16.

When the hold down bars and panels are initially installed the hold down bars 20 are loosely fastened and then the majority of the panels are inserted except a few which will allow access to the bolts to be tightened to secure the hold down bar. Once the hold down bars are fixed there is no need to remove them to fit or remove panels. The panels are pushed into place by forcing the ends of the panels 11 past the flanges 22 of the hold down bars. To remove the panels a lever such as a screw driver is inserted into the space 24 provided in the hold down bar flange 22 to lever the edge out past the flange 22.

As shown in figures 4 and 5 the side portions of the deck are held in place by the side bars 30 which are tightened in place using the wedges 32 which are forced between the brackets 33 and the side bars A second embodiment of the invention is illustrated in figures 6 and 7 where a two tier hold down panel is used to secure the panels in a double deck screen deck.

The screen deck consists of two arrays of rectangular screening panels 11 extending lengthwise between frame members 43 and being secured in place by hold down bars 50 to the support flanges 44 of the frame members 43. The flanges 52 of the hold down bars 50 bear down on the edge surface of the ends of the panels 11 in the lower deck while the flanges bear down on the edges of the panels 11 in the upper deck. The support flange 53 supports the lower edge of the ends of the panels 11 in the upper deck. The panels of the lower deck seat on the cover strip 58 which is seated on the frame flange 44. The nut 47 on the shaft 46 secures the hold down panel 50 to the frame flange 44.

The hold down bars 50 as shown, are long enough to extend across four screening panels 11 and are secured to the frame flanges 44 by bolts 47 mounted on the screw threaded shaft 46 which extend up into the body 51 of the hold down panels 50. The screw threaded shafts 46 screw into complementary threaded tubular reinforcements 56 embedded in the body 51 of the hold down panels 50. The body 51 of the panel is thickened between the flanges 52 and 53 to strengthen the panel 50. The extension of the shafts 46 past the flanges 53 also add rigidity and vertical strength to the panels.

To protect the frame flanges 44 from abrasive material being screened, cover strips 58 are placed between the panels 11 and the frame flange 44.

The cover strips 58 may be integrally moulded with the hold down panels The preferred material is polyurethane similar to the material used for the panels 11. A washer 57 which abuts the shaft 46 lies between the nut 47 and the frame flange 44.

In both embodiments the loss of available screening surface at the margins io of the panel is less than in prior art panels. The margins may be reduced to compared to 75 mm in prior art hold down bar arrangements. This translates as a 15% increase in the available open screening area of the panels.

The embodiments shown in figures 8 and 9 are for use with panels that have a rib or projection on the end faces that abut the body portion 23 of the hold down bars. The hold down bars of figures 8 and 9 are the same as those described in figures 1 to 3 except that they include a recess 36 (figure 8) or 37 (figure 9) which receives a complementary shaped rib of the screen panel (not shown). The recess 37 is shaped to provide room to manouvre the panel into place.

The arrangement of this invention also has the advantage that no other support frame is required other than the frame of the screening machine itself.

Those skilled in the art will realize that the invention may be put into practice in other embodiments but utilizing the essential elements as defined herein.