AU4116099A - Screen deck module - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): POLYSCREEN PTY LTD A.C.N. 008 521 702 Invention Title: SCREEN DECK MODULE a. a a.

The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 SCREEN DECK MODULE This invention relates to a screen panel module for a screen deck.

Screen panel modules generally comprise of polyurethane panel reinforced by a reinforcing frame. The reinforcing frame is embedded within the panel and the panel has apertures of a particular size to screen material. When the screen deck modules are assembled in a screen deck the modules wear due to impact of material which is being screened and from time to time the screen deck must be shut down so that modules can be replaced. The need to replace complete modules is generally expensive.

The present invention may be said to reside in a screen deck module for a screen deck including; a base frame having four side frame members defining a substantially rectangular configuration; at least two of the side members including part circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts 25 are splayed outwardly to secure the modules to a frame of the screen deck; a separate screen member for location on the base frame, the screen member having an aperture configuration for screening material; and aligned holes in the base frame and the screen member for receiving a fastener to releasably connect the screen member to the base frame.

The present invention may also be said to reside in a screen member for coupling with a base frame to form a screen deck module for a screen deck, the base frame having four side frame members defining a substantially H:\pauad\Keep\pei\POLYSCP.EEN-screen-de k-mdu.ledoc 27/07/99 3 rectangular configurations and having a plurality of holes, at least two of the side members including part circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts are splayed outwardly to secure the modules to a frame of the screen deck, the screen member including an outer periphery; an aperture configuration for screening material; and holes in the outer periphery of the screen member for alignment with the holes in the frame member for receiving a fastener to releasably connect the screen member to the base frame.

The present invention may also be said to reside in a base frame for coupling with a screen member to form a screen deck module for a screen deck, the screen member having an 20 outer periphery and an aperture configuration, a plurality of holes in the outer periphery, the base frame including; S* four side frame members defining a substantially rectangular configuration; at least two of the side members including part 25 circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts are splayed outwardly to secure the modules to a frame of the screen deck; and holes in the base frame for alignment with the holes in the screen member for receiving a fastener to releasably connect the screen member to the he base frame.

Because the base screen member is releasably connected to the base, when the screen member wears out the screen member can be removed from the base by removing the H:\paulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07/99 4 connectors and a new screen member located on the base.

Thus, it is not necessary to replace the entire module but only the screen member thereby saving material and therefore costs.

Furthermore, if it is desirable to change the nature of the screen module by providing a different aperture configuration or type, the screen member need only be removed and replaced by a new screen member having the desired aperture configuration or type. Thus, the flexibility of the screen deck is increased as is the ability to reduce down time for repair of the screen deck by replacing screen members or changing the configuration of the screen deck by inserting different types of screen 15 members.

Preferably the screen member has a peripheral frame portion matching the configuration of the base and at least two sides of the peripheral frame portion having semicircular 20 recesses which register with the recesses of the base when the screen member is located on the base.

Preferably the connector comprises a conventional splayed leg type connector or screw.

Preferably the base has a cut out on a lower surface thereof in registry with each of the holes.

Preferably the cut outs on the sides of the base which do not have the skirts and recesses extends for the entire length of those sides.

Preferably the cut out on the sides having the recesses and skirts extends between the semicircular recesses and skirts.

H:\paulad\Keep\speciPOLYSCREEN-screen-deck-module.doc 27107/99 5 A further aspect of the invention may be said to reside in a screen deck module for a screen deck including: a base frame having four side frame members defining a substantially rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members; at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection.

having a reduced diameter neck portion and an enlarged outer end portion; a separate screen member for location on the base frame, the screen member having four side frame members including first and second opposed pairs of frame members 15 and an aperture configuration, the other of the said groove or projection being provided on at least the first pair of opposed frame members; and wherein the separate screen member is releasably coupleable to the base frame by locating the screen member 20 on the base frame so that the projection engages in the groove.

This aspect of the invention may also be said to reside in a screen member for a screen deck having a base frame 25 having four side frame members defining a substantially S* rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members, at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection having a reduced diameter neck portion and an enlarged outer end portion, the screen member including: four side frame members including first and second opposed pairs of frame members and an aperture configuration, the other of the said groove or projection H: \paulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07. 99 6 being provided on at least the first pair of opposed frame members; and wherein the separate screen member is releasably coupleable to the base frame by locating the screen member on the base frame so that the projection engages in the groove.

This aspect of the invention may also be said to reside in a base frame for a screen deck module for a screen deck, the base frame including: four side frame members defining a substantially rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members; 15 at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection having a reduced diameter neck portion and an enlarged outer end portion; and 20 the base frame being coupleable to a separate screen member having four side frame members including first and second opposed pairs of frame members and an aperture configuration, the other of the said groove or projection being provided on at least the first pair of 25 opposed frame members by locating the screen member on the base frame so that the projection engages in the groove.

In this embodiment, when the screen member wears out, the screen member can be removed from the base by releasing the groove from the projection and connecting a new screen member to the base. Thus, one again, it is not necessary to replace the entire module but only the screen member thereby saving material and therefore costs.

Preferably the base frame member has part circular recesses on the second pair of opposed frame members, the part circular recesses having downwardly extending skirts so H:\paulad\Keep\speci\POLYSCREEN-screen-de ck-module.doc 27/07/99 7 that when two modules are placed side by side, the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush, the skirts are splayed outwardly to secure the module to a frame of a screen deck.

Preferably the grooves are located on the base frame and the projections on the separate screen member.

Preferably the enlarged outer portion of the projection and the inner portion of the groove are of generally circular cross-section.

Preferably the shape of the groove corresponds to the shape 15 of the projection and the projection slightly deforms a peripheral side edge portion of the raised frame member or screen member so that the projection can enter into the groove to locate in the groove.

Preferably the projection and groove extend the entire length of the respective first pair of opposed frame members.

Preferably the second pair of opposed frame members of the 25 base of the second pair of opposed frame members of the screen member also have a groove and an engaging projection.

A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings in which; Figure 1 is a schematic view illustrating the module of the present invention; Figures 2a and 2b show conventional fasteners used with the embodiment of Figure 1; Figure 3 is a view along the line 33 of Figure 1; H: \paulad\Keep\speci\POLYSCREEN-screen-deck-nmodleFdoc 27/07/99 8 Figure 4 is a view along the line IV IV of Figure 1; Figure 5 and Figure 6 are views showing the coupling of the module using the fasteners of Figures 2a and 2b; Figure 7 is a view of a separate screen member according to a further embodiment of the invention; Figure 8 is a view of a base member for use with the screen of Figure 7; Figure 9 is a cross-sectional view along the line IX-IX of Figure 7; Figure 10 is a cross-sectional view along the line X-X of Figure 8; Figure 11 is a cross-sectional view showing the 15 components of Figures 9 and 10 assembled; Figure 12 is a side view of the base member shown in Figure 8; and Figure 13 is a view of a reinforcing frame used in the embodiment of Figures 7 and 8.

20 With reference to Figure 1 a screen deck module according to the preferred embodiment invention is shown.

The module 10 includes a base frame 12 having four sides 12a 12b 12c and 12d.

25 The sides 12a and 12c have semicircular recesses 14 and depending skirts 16. The configuration of the semicircular recesses 14 and skirts 16 is well known and the skirts 16 are provided with tapering grooves 18. When two like modules are placed side by side the semicircular recesses 14 of the modules form a circular opening and the skirts 16 form a bush having a tapering bore formed from the grooves 18. The bush locates through a hole (not shown) in a frame (not shown) of the screen deck (not shown). A pin (not shown) can be forced into the recess 14 and through the bore so as to cause the skirts 16 to splay outwardly to lock the bush formed from the two skirts 16 to the frame member of the screen deck. This technique is well known H: paulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07/99 9 and therefore will not be described in further detail herein.

The base 12 is provided with holes 20 which pass through the sides 12a to 12d.

A screen member 30 is provided for connection to the base 12 and has a peripheral frame 32 of the same configuration as the base 12. The peripheral frame 32 is provided with holes 40 which register with the holes 20 in the base 12.

The frame 32 carries a screen media portion 34. The screen member 30 may be formed from polyurethane and have apertures which define the screen media 34. Alternatively, screen member 30 may be formed from metal and be provided 15 with wires which define the apertures of the screen member 34. In other embodiments the combination of polyurethane and metal configurations can be provided. Thus, the screen member 30 may be a polyurethane member, woven wire member, punch plate member, rubber member, wedge wire member etc.

20 As clearly seen in Figure 1 the peripheral frame portion 32 is provided with semicircular recesses 36 on two opposed sides which register with the semicircular recesses 14 of the base 12.

Figures 2a and 2b show schematic diagrams of conventional, "buy over the counter, connectors which may be used with the embodiment of Figure 1. Figure 2a shows a conventional splayed leg type fastener which has a outer member having legs 45 into which is inserted a pin 46 for causing the legs 45 to splay. Figure 2b shows a conventional screw As shown in Figures 3 and 4 the frame portions 12b and 12d have a cut out 60 which extends along the entire length of the sides 12a and 12b at the lower outer corner of the sides 12a 12b. The holes 20 register with the cut out so that the holes extend from an upper portion 15 of the SH:\paulad\Keep\speci\POLYSCREEN-screen-dck-module.doc 27/07/99 10 sides 12b and 12d down to an upper wall 62 of the cut out The sides 12c are also provided with cut outs 70 in the lower outer corner which extend between the skirts 16 which extend downwardly from the sides 12c and 12a.

In order to secure the screen member 30 to the base 12 the screen member 30 is located on the base 12 with the holes 40 and 20 in registry and with the recesses 30 in registry with the recesses 14. A connector, such as the connector shown in Figure 2a or 2b, is then inserted through the holes 40 and the holes 20. In the case of the connector shown in Figure 2a and 5 the legs 45 extend down into the cut out 60 which provides room for the legs to be splayed apart when the pin 46 is inserted into the fastener so as to lock he fastener in place and therefore lock the screen member 30 to the base 12. In case of the screw shown in Figure 2b and Figure 6 the screw 50 is simply screwed 20 through the aligned holes 40 and 20 and into the polyurethane material of the base 12 so as to couple the screen member 30 to the base 12.

In order to release the screen member 30 from the base 12 the pin 46 is removed from the fastener shown in Figures 2a and 5 so that the fastener can be removed from the holes and 20 and in the case of Figure 6 the screw 50 can simply be unscrewed from the base 12 and screen member 30. Thus, different screen members can be located on the base and secured in place as screen members wear out or as it is desired to change the configuration of the screen deck.

The base 12 may include a metal reinforcing frame or plastics reinforcing frame which is embedded in the polyurethane material of the base 12 as exemplified by reference 70 in Figures 3 and 4. The reinforcing frame may be embedded in the base 12 when the base 12 is moulded.

H: \paulad\Keep\speci\POLYSCREEN-screen-deck-mdule.doc 27/07/99 11 Figures 7 and 8 show a further embodiment of the invention which a base frame 80 and a separate screen member 82 are provided. Once again, the base frame 80 has four side frame members 84, 86, 88 and The opposed frame members 84 and 88 have semi-circular recesses and appending skirts 94 which are the same as those described with reference to the previous embodiment and function in exactly the same way.

In this embodiment, opposed frame members 90 and 86 have a groove 100 which extend all the way along their length.

The other opposed side frame members 84 and 88 also have a groove 102 which extends only between the semi-circular recesses and appending skirts 94.

As-.shown in Figure 7, the separate screen module 82 has a rectangular peripheral frame 104 which includes side frame 20 members 106, 108, 110 and 112. The opposed frame members 108 and 112 have semi-circular cutouts 114 which function *in the same manner as the cutouts 36 described with reference to the previous embodiments. Side frame member 110 and side frame member 106 have an integral depending 25 projection 120 which extend the entire length of the side frame members 110 and 106. The other pair of opposed side frame members 108 and 112 also have a projection corresponding in shape to the projections 120 but which extend only between the semi-circular recesses 114 and which are shown generally in dotted lines in Figure 7. The projections on the sides 108 and 112 are shown by reference numeral 122.

The projections 120 correspond to the grooves 100 in the side edges 90 and 86 of the base 80 and the projections 122 correspond with the projections 102 in the other pair of opposed side frame members 84 and 88 of the base H: \paulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07/99 12 Figures 9 and 10 show the cross-sectional configuration of the projection 120 and the groove 100.

As best shown in Figure 9, the projection 120 has a narrow neck portion 120a and a large generally circular outer end 120b. The groove 100 is shaped correspondingly to the projection 120 and has a narrow neck 100a and an enlarged circular inner portion 100b. The groove 102 and the projection 122 are shaped in exactly the same manner as is shown in Figures 9 and In order to secure the separate screen module 82 to the base 80, the projections 120 and 122 are located within the 15 grooves 100 and 102 as shown in Figure 11. In order to accommodate the enlarged head 120b through the narrow neck 100a of the groove 100, the peripheral side edge portion 140 of the frame member 90 is deflected outwardly in the direction of arrow A as the enlarged head portion 120b 20 passes through the neck 100a. When the enlarged head portion 120b locates within the corresponding shaped S" enlarged inner portion 100b and the neck 100a locates in the neck 100a, then the peripheral side portion 140 can resiliently return to the position shown in Figure 11.

"The separate screen member 82 can be secured to the base by merely forcing the screen member down onto the base so that the projections 120 and 122 locate within the corresponding grooves 100 and 102. This could be done by simply locating the screen member upside down on a floor and locating the base over the screen member and merely standing on the peripheral frame members of the base to force the projection 120 in the grooves 100 (and the projections 122 into the grooves 102).

In order to remove a worn screen member 82, a screwdriver is inserted between the base 90 and screen member 82 and H:\paulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07/99 13 the screwdriver used to merely ply the projections 120 and 122 out of their corresponding grooves 100 and 102. A new screen member can then be located on the base as is required.

In order to strengthen the side frame members 86 and the frame members may be provided with a reinforcing rail 150 which is merely moulded integral with the base member and which is located below the frame members as shown in Figures 8 to 13.

As is evident from Figures 10 to 13, the reinforcing rail 150 extends along the side frame members 86 and 90 which do not have the skirts 94 which facilitate coupling of the panels to the frames (not shown) of the screening machine (not shown). When the screen panels are located on the screening machine the side edges 84 and 88 which do have the skirts 94 will be supported on the frames (not shown) and therefore will be prevented from bowing by virtue of 20 their support on those frames. However, the frame members 86 and 90 traverse the space between adjacent frames (not shown) and it is possible that during screening action the frame members 86 and 90 will bow to an extent which would cause the projections 120 to be pulled or forced out of the 25 grooves 100 and therefore unwantingly release the screen member 82 from the base The reinforcing rails 150 stiffen the frame members 86 and and prevent them from bowing and thereby preventing unwanted release of the projections 120 from the grooves 100.

As clearly seen in Figure 8 and also Figure 12 the rails 150 terminate inwardly of frame members 84 and 88 thereby ensuring they do not interfere with the frames (not shown) of the screening machine (not shown) on which the frame H: \paulad\Keep\speci\POLYSCREEN-screen-d.k-module.doc 27/07/99 14 members 84 and 88 sit when the screen panels are located on the screening machine.

A reinforcing frame 160 (see Figure 13) is imbeded into the base member 80 and comprises sides 161, 162, 163 and 164.

The sides 161 and 162 are imbeded in the frame members and 86 respectively. The sides 161 and 162 are higher than the sides 163 and 164 by being provided with downwardly projecting portions 167 which are defined between cut-outs 165. The cut-outs 165 are formed flush with the bottom of sides 163 and 164 which are welded between sides 161 and 162 and ensure that the reinforcing frame does not interfere with the seating of the frame members 84 and 88 :15 on the frames of the screening machine. The portions 167, as is best shown in Figure 12, project down into the reinforcing rails 150 to further stiffen the frame members 86 and 90. Thus, the frame members 86 and 90 are reinforced by the reinforcing rails 150 which are moulded integral with the frame members 86 and 90 and also by the 20 side walls 161 and 162 of the frame 160 which carry the downwardly extending portions 167 which project into the *reinforcing rails 150.

The increased height of the sides 161 and 162 and the 25 reinforcing rails 150 prevent bowing of the side members 86 and 90 to prevent the unwanted release of the projections 120 out of the grooves 100 as discussed above.

As in the previous embodiments, the screen member 82 carries a screen media portion 130 which can be the same as the screen media portion 34 described in the previous embodiment.

Thus, the preferred embodiments of the invention provides a screen deck module which results in less down time on the screen machine, a lower cost wearing surface (as a reinforced base frame can be reused) and the adaptability H: \paulad\Keep\speci\POLYSCREEN-scren-deck-odule.doc 27/07/99 15 of being able to incorporate various different screen media members.

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiments described by way of example hereinabove.

Dated this 27th day of July 1999

POLYSCREEN

By their Patent Attorneys: 15 GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia.

5 0 *5 **oo 6 0 88 HK\paulad\Keep\speci\OLYSCREN-sreen-deck-module.doc 27/07/99

Claims (21)

1. A screen deck module for a screen deck including: a base frame having four side frame members defining a substantially rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members; at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection having a reduced diameter neck portion and an enlarged outer end portion; a separate screen member for location on the base S frame, the screen member having four side frame members 15 including first and second opposed pairs of frame members and an aperture configuration, the other of the said groove or projection being provided on at least the first pair of opposed frame members; and wherein the separate screen member is releasably 20 coupleable to the base frame by locating the screen member on the base frame so that the projection engages in the groove.

2. A screen member for a screen deck having a base 25 frame having four side frame members defining a substantially rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members, at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection having a reduced diameter neck portion and an enlarged outer end portion, the screen member including: four side frame members including first and second opposed pairs of frame members and an aperture configuration, the other of the said groove or projection H: \paulad\Keep\pei\POLYSCREEN-screen-deck-odule.doc 21/07/99 17 being provided on at least the first pair of opposed frame members; and wherein the separate screen member is releasably coupleable to the base frame by locating the screen member on the base frame so that the projection engages in the groove.

3. A base frame for a screen deck module for a screen deck, the base frame including: four side frame members defining a substantially rectangular configuration, the four side frame members including a first pair of opposed frame members and a second pair of opposed frame members; at least the first pair of opposed frame members having one of a an elongate groove which has a narrow neck portion and an enlarged interior portion, or a projection having a reduced diameter neck portion and an enlarged outer end portion; and the base frame being coupleable to a separate screen member having four side frame members including first and second opposed pairs of frame members and an aperture configuration, the other of the said groove or projection being provided on at least the first pair of opposed frame members by locating the screen member on the base frame so that the projection engages in the groove.

4. A screen deck module according to claim 1, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the base frame member has part circular recesses on the second pair of opposed frame members, the ij circular recesses having downwardly extending skirts so that when two modules are placed side by side, the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush, the skirts are splayed outwardly to secure the module to a frame of a screen deck.

H:\paulad\Keep\speci\POLYSCREEN-screen-deck-moduie.doc 27/07/99 18 A screen deck module according to claim 1, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the grooves are located on the base frame and the projections on the separate screen member.

6. A screen deck module according to claim i, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the enlarged outer portion of the projection and the inner portion of the groove are of generally circular cross-section.

7. A screen deck module according to claim 1, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the shape of the groove corresponds to the shape of the projection and the projection slightly deforms a peripheral side edge portion of the raised frame member or screen member so that the projection can enter into the groove to locate in the groove. 20

8. A screen deck module according to claim i, or a .oo. screen deck according to claim 2, or a base frame according to claim 3, wherein the projection and groove extend the *.entire length of the respective first pair of opposed frame members.

9. A screen deck module according to claim i, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the second pair of opposed frame members of the base of the second pair of opposed frame members of the screen member also have a groove and an engaging projection.

A screen deck module according to claim 14, or a screen deck according to claim 2, or a base frame according to claim 3, wherein the second pair of opposed frame members of the screen member are locatable on a frame member of a base frame of a screening machine, and wherein H:\paulad\Keep\speci\POLYSCREE-screen-dek-moduledoc 27/07/99 19 the first pair of opposed frame members include reinforcing means for reinforcing the first pair of frame members to prevent bowing of the first pair of frame members and therefore unwanted release of the projection from the elongate groove.

11. A screen deck module according to claim 10, or a screen deck according to claim 10, or a base frame according to claim 10, wherein the reinforcing means comprises a reinforcing rail formed below and integral with the first pair of opposed frame members.

12. A screen deck module according to claim 11, or a "screen deck according to claim 11, or a base frame "15 according to claim 11, wherein the reinforcing rail terminates inwardly of ends of the first pair of opposed frame members so that the reinforcing rail does not prevent seating of the second pair of frame members on the frames of the screening machine.

13. A screen deck module according to claim 11 or 12, or a screen deck according to claim 11 or 12, or a base frame member according to claim 11 or 12, wherein a reinforcing frame in embeded in the base frame member, the reinforcing frame having a pair of opposed sides which are embeded in the first pair of opposed frame members respectively, the sides of the reinforcing frame having extension portions which locates in the reinforcing rail, and cut-outs at the ends of the first and second opposed sides of the reinforcing frame which define the extension portions and prevent the first and second portions from interfering with location of the second opposed pair of frame members on the frames of the screening machine.

14. A screen deck module for a screen deck including; a base frame having four side frame members defining a substantially rectangular configuration; H:\paulad\Keep\speci\POLYSCREEN-scren-deck-modul.doc 27/07/99 20 at least two of the side members including part circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts are splayed outwardly to secure the modules to a frame of the screen deck; a separate screen member for location on the base frame, the screen member having an aperture configuration for screening material; and aligned holes in the base frame and the screen member for receiving a fastener to releasably connect the screen member to the base frame.

15 15. A screen member for coupling with a base frame to form a screen deck module for a screen deck, the base frame having four side frame members defining a substantially rectangular configurations and having a plurality of holes, at least two of the side members including part circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts are splayed outwardly to secure the modules to a frame of the screen deck, the screen member including an outer periphery; an aperture configuration for screening material; and holes in the outer periphery of the screen member for alignment with the holes in the frame member for receiving a fastener to releasably connect the screen member to the base frame.

16. A base frame for coupling with a screen member to form a screen deck module for a screen deck, the screen member having an outer periphery and an aperture H:\pulad\Keep\speci\POLYSCREEN-screen-deck-module.doc 27/07/99 21 configuration, a plurality of holes in the outer periphery, the base frame including; o four side frame members defining a substantially rectangular configuration; at least two of the side members including part circular recesses and downwardly extending skirts so that when two modules are placed side by side the part circular recesses form an opening and the skirts form a bush so that when a pin is inserted into the opening and bush the skirts are splayed outwardly to secure the modules to a frame of the screen deck; and holes in the base frame for alignment with the holes in the screen member for receiving a fastener to releasably connect the screen member to the he base frame.

17. A screen deck module according to claim 14, or 16, or a screen deck according to claim 14, 15 or 16 or a-base frame according to claim 14, 15 or 16, wherein the screen member has a peripheral frame portion matching the configuration of the base and at least two sides of the peripheral frame portion having semicircular recesses which register with the recesses of the base when the screen member is located on the base.

18. A screen deck module according to claim 14, or 16, or a screen deck according to claim 14, 15 or 16 or a base frame according to claim 14, 15 or 16, wherein the connector comprises a conventional splayed leg type connector or screw.

19. A screen deck module according to claim 14, or 16, or a screen deck according to claim 14, 15 or 16 or a base frame according to claim 14, 15 or 16, wherein the base has a cut out on a lower surface thereof in registry with each of the holes.

H: \paulad\Keep\speci\POLYSCREEN-screen-deck-modue.doc 27/07/99 22 A screen deck module according to claim 19 or a screen deck according to claim 19 or a base frame according to claim 19, wherein the cut outs on the sides of the base which do not have the skirts and recesses extends for the entire length of those sides.

21. A screen deck module according to claim 20 or a screen deck according to claim 20 or a base frame according to claim 20, wherein the cut out on the sides having the recesses and skirts extends between the semicircular recesses and skirts. e H:\paulad\Keep\speci\POLYSCREEN-screen-deck-moduLe.doc 27/07/99