S&F Ref: P039029 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address ESS Engineering Services & Supplies Pty Limited, of Applicant: an Australian company, ACN 001 931 746, of Lot 6, Traders Way, Currumbin, Queensland, 4223, Australia Actual Inventor(s): Robert Law Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: A screen assembly Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2011902986 27 Jul 2011 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(6358270_1) 1 A SCREEN ASSEMBLY Technical Field The present invention relates to screen assemblies and more particularly but not exclusively to screen assemblies to be attached to conveyors. Background of the Invention In the mining industry it is preferable that screens are located at the longitudinally extending sides of a conveyor to inhibit material falling from the conveyor, for obvious safety reasons. More particularly the screens are also provided to inhibit personal contact with the conveyor, as is required by various standards. A disadvantage of known screen assemblies is that they are difficult to position relative to the conveyor and are difficult to position at locations where the conveyor changes direction. This often requires individual design and manufacture at high cost. Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages. Summary of the Invention There is disclosed herein a screen assembly for a conveyor having a longitudinal direction of extension, the conveyor including a conveyor frame, the assembly including: at least one screen panel to be fixed to the frame so as to extend upwardly; a plurality of standards, the standards being generally parallel and transversely spaced, and to be fixed to the frame so as to extend longitudinally generally normal to said direction; 2 a plurality of stringers, the stringers being generally parallel and transversely spaced and generally perpendicular to the standards; a set of first securing brackets attached to the standards for fixing the standards to the frame, the first brackets providing for position adjustment of the standards in the longitudinal direction of extension of the standards; a set of second securing brackets, the second brackets being attached to the stringers and attached to the standard so as to provide for position adjustment of the stringers in the longitudinal direction of extension of the stringers; a set of third brackets, the third brackets being attached to the standards and panels to fix the panels to the stringers. Preferably, wherein each bracket includes at least one socket portion through which an associated one of the standards or stringers is slidable until fixed thereto. Preferably. wherein each socket portion has a threaded fastener that is operated to fix the associated stringer or standard to the socket portion. Preferably, wherein each panel includes a frame and mesh fixed thereto. Brief Description of the Drawings A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a schematic isometric view of a conveyor and a screen assembly; Figure 2 is a schematic isometric view of portion of the conveyor frame, a first bracket; Figure 3 is a schematic isometric view of a second bracket; Figure 4 is a schematic isometric view of a third bracket; and 3 Figure 5 is a schematic isometric view of the bracket of Figure 3 in a different orientation. Detailed Description of the Preferred Embodiment In the accompanying drawings there is schematically depicted a conveyor 10 that includes a longitudinally extending conveyor belt 11 supported by a conveyor frame 12. The belt 11 conveys the material in the direction 13, that is the longitudinal direction of extension of the conveyor 10. The frame 12 includes longitudinally extending frame members 14 that would typically support rollers that in turn support the belt 11 for movement in the direction 13. Fixed to the frame 12 is a screen assembly 15. The screen assembly 15 includes a plurality of standards 16 fixed to the frame members 14, with a plurality of stringers 17 fixed to the standards 16. Fixed to the stringers 17 is a plurality of panels 18. Each of the panels 18 is of a square or rectangular configuration and includes a frame 19 to which there is fixed mesh 20. A first set of brackets 21 secure the standards 16 to the frame members 14, a second set of brackets 22 secures the stringers 17 to the standards 16, while a third set of brackets 23 secures the panels 18 to the stringers 17. The brackets 21 include a flange 24 that via threaded fasteners 25 secures the brackets 21 to the frame members 14. Each of the brackets 21 further includes a socket portion 26 through which an associated one of the standards 16 passes so as to be height adjustable in the direction 27, that is the longitudinal direction of extension of the standards 16. Each socket portion 26 has a pair of threaded fasteners 28 that engage the associated standard 16 to secure the standard 16 in position when correctly positioned. Each standard 16 is slidable through its associated socket portion 26 until the associated fastener 28 is operated to fix the standard 16 in the socket portions 26.
4 Each of the brackets 22 includes a first socket portion 29 through which an associated stringer 17 passes, as well as a second socket portion 30 through which an associated standard 16 passes. Engaged with the socket portion 29 is a pair of threaded fasteners 31 that engage the associated stringers 17 to fix the stringers 17 when correctly positioned. Engaged with the second socket portion 30 is a pair of threaded fasteners 32 that engage the associated standard 16 when the bracket 22 is correctly positioned. The standard 16 and stringers 17 are slidable through the associated socket portion 29, 30 until the associated fastener 31 is operated to secure them in position. Mounted on the stringer 17 is a plurality of the third brackets 23. Each of the brackets 23 includes a socket portion 33 that engages the associated stringer 17. The brackets 23 are adjustable in the direction 36, that is the direction of the longitudinal extension of the stringers 17. Threaded fasteners 34 are associated with the socket portion 33 and are operable to secure the brackets 23 to the associated stringer 17 when correctly positioned. Each stringer 17 is slidable through the associated socket portion 33. Once the stringer 17 is in position the associated fastener 34 secures it in position. Each of the frames 19 includes an upper flange 37 to rest upon an associated one of the stringers 17. Each of the flanges 13 includes a plurality of apertures 38. Each of the brackets 23 includes a catch assembly 35. Each catch assembly 35 includes a pair of projections 39 that are spaced so as to provide a slot 43. Located in each slot 43 is a wedge member 41 having a diagonally extending slot 42. A pin 40 passes through each slot 42 and pivotally attaches the associated wedge member 41 to each projections 39. Each wedge member 41 is pivotally movable to a position extending generally normal to its associated stringer 17 (as shown in Figure 3) and a position at which the wedge member 41 extends generally longitudinally parallel to the associated stringer 17. With the brackets 23 positioned as shown in Figure 4, the catch assemblies 35 pass through the apertures 38 to aid in securing the panels 18 in position. With the brackets 23 as oriented in Figure 3, the catch assemblies 35 extend through the mesh 20.
5 The catch assemblies 35 are able to pass through the apertures 38 and mesh 20 when the wedge members 41 are positioned a shown in Figure 3. However once passing through the apertures 23 and mesh 20, the wedge members 41 are pivoted so as to extend longitudinally generally parallel to their associated stringer 17 and the wedge members 41 moved so that the pins 40 pass along the slots 42. As can be seen, the slots 42 are inclined so that the wedge members 41 wedge the panels 18 in position.