Screening Arrangement

Abstract

A screening panel 10 comprises a peripheral frame 12 consisting of a pair of mutually laterally spaced side members 14, 16, which are integral with a pair of mutually axially spaced end members 18, 20. The side members 14, 16 and end members 18, 20 define corners of the panel 22.1, 22.2, 22.3 and 22.4 and the peripheral frame 12 where they meet. A plurality of mutually spaced ribs 15 extend across the periphery of the panel 10 to define a screening surface. The side members and end members are rectangular in cross-section, thereby defining substantially flat upper peripheral surfaces 12.1, outer peripheral surface 12.2 and lower peripheral surface 12.3 of the peripheral frame 12 and thus also the panel 10. The panel 10 includes locating recesses 24 provided at or near to the corners 22.1, 22.2, 22.3 and 22.4 of the panel 10. The panel 10 also has separate securing recesses in the form of semi-circular grooves 30 formed in the lower surface 12.3 of the panel 10, around the locating recess 24 and concentrically therewith.

1 . A screening element securing device for securing a screening element to a screen support frame, said securing device including 
 a body portion having a connecting formation for connection to a complementary formation on a screen support member of a screen support frame to render the screening element securing device releasably connected to the screen support member; and    a locating formation, provided on the body portion, for engagement with a complementary formation on a screening element to locate the screening element on the screen support frame.    
     
     
         2 . A securing device as claimed in  claim 1  wherein the body portion comprises an insert for insertion in an opening in the screen support member, the connecting formation being provided on the insert and being for connection to a complementary formation in the opening.  
     
     
         3 . A securing device as claimed in  claim 2  wherein the locating formation is provided on the insert and comprises a locating protrusion for location in a locating recess of a screening element.  
     
     
         4 . A securing device as claimed in  claim 3  wherein the locating protrusion comprises a shank which extends axially away from the body portion, and a head formed at the free end of the shank.  
     
     
         5 . A securing device as claimed in  claim 3  or  claim 4  which includes a securing formation, separate from the locating formation, which is receivable in a complemental securing formation on the screening element.  
     
     
         6 . A securing device as claimed in  claim 5  where the separate securing formation comprises a separate securing protrusion.  
     
     
         7 . A securing device as claimed in  claim 6  wherein the separate securing protrusion comprises an annular ridge which stands proud axially of the insert and around the locating protrusion.  
     
     
         8 . A securing device as claimed in  claim 7  wherein the connecting formation comprises a screw thread for connection to a complementary connecting formation comprising a complementary screw thread.  
     
     
         9 . A securing device as claimed in  claim 8  wherein the insert is substantially cylindrical, the screw thread being provided on its outer surface, and the insert, shank, head and the annular ridge being unitary.  
     
     
         10 . A securing device as claimed in  claim 7  wherein the insert comprises a peripheral flange and a skirt fast with the flange, the connecting formation connectable with a complementary connecting formation on a screen support member being a peripheral radially outwardly facing groove defined in the body portion between the flange and the skirt, the body portion being resiliently deformable, the annular ridge standing proud axially of the peripheral flange, the insert defining an axial bore for receiving a pin which pin includes the shank and the head.  
     
     
         11 . A securing device as claimed in  claim 2  wherein the insert defines a locating formation in the form of a secondary opening for engaging the complementary formation on the screening element for locating and securing the screening element to the screen support member, the connecting formation on the insert comprising an external radially outwardly facing peripheral groove for connection with a complementary connecting formation in the form of an opening in a screen support member.  
     
     
         12 . A securing device as claimed in  claim 11  wherein the insert comprises a peripheral flange and a skirt fast with the flange, the external peripheral groove being defined in the insert between the flange and the skirt, the skirt and the flange defining the secondary opening.  
     
     
         13 . A securing device as claimed in  claim 2  wherein the insert defines a locating formation in the form of a secondary opening for engaging the complementary formation on the screening element for locating and securing the screening element to the screen support member, the connecting formation on the insert being in the form of an external screw thread connectable with a complementary screw thread in an opening in the screen support member.  
     
     
         14 . A securing device as claimed in  claim 13  wherein the insert comprises a peripheral flange and a skirt fast with the flange, the screw thread being provided on the outer surface of the skirt, and the skirt and the flange together defining the secondary opening.  
     
     
         15 . A securing device as claimed in  claim 1 , which is of a hard-wearing synthetic plastics material.  
     
     
         16 . A screening element which has a peripheral frame defining an opening across which a plurality of mutually spaced ribs extend to define a screening surface, the peripheral frame having an upper surface on the same side of the screening element as the screening surface, a lower surface on its side opposite its upper surface and an outer peripheral surface interconnecting the upper and lower surfaces, the peripheral frame being provided on its lower surface with locating formations for engagement with complementary locating formations on a screen support frame to locate the screening element on the screen support frame, and the peripheral frame being provided on its lower surface with separate securing formations for engagement with complementary separate securing formations on the screen support frame to secure the screening element against displacement on the screen support frame.  
     
     
         17 . A screening element as claimed in  claim 16  wherein the locating formations include locating recesses provided in the lower surface of the peripheral frame, respectively for receiving locating means in the form of locating protrusions on the screen support frame, for locating adjacent screening elements in position on the screen support frame.  
     
     
         18 . A screening element as claimed in  claim 16  wherein the separate securing formations include securing recesses provided in the lower surface of the peripheral frame, respectively for receiving securing means in the form of securing protrusions on the screen support frame, for securing the screening element against displacement on the screen support frame.  
     
     
         19 . A screening element as claimed in  claim 17  or  claim 18 , which is in the form of a screening panel, the peripheral frame comprising a pair of mutually laterally spaced side members which are integral with a pair of mutually longitudinally spaced end members, said side members and end members defining corners of the panel and peripheral frame where they meet.  
     
     
         20 . A screening panel as claimed in  claim 19  wherein the side members and end members of the frame are rectangular in cross-section, thereby defining a substantially flat upper surface, a substantially flat lower surface and a substantially flat outer peripheral surface for the peripheral frame.  
     
     
         21 . A screening panel as claimed in  claim 20  wherein the locating recesses are provided at or near the corners of the panel.  
     
     
         22 . A screening panel as claimed in  claim 21  wherein the locating recesses intersect the outer peripheral surface of the peripheral frame, and are shaped such that when similar locating recesses on adjacent panels are brought into register, they and the similar locating recesses together define a locating socket into which a locating protrusion on the screen support frame is receivable to locate adjacent panels in position on the support frame.  
     
     
         23 . A screening panel as claimed in  claim 22  wherein the separate securing recesses are formed in the panels near the locating recesses.  
     
     
         24 . A screening panel as claimed in  claim 23  wherein the securing recesses are endless grooves formed in the lower peripheral surface of the panel, each extending partly around one of the locating recesses, there being a securing recess for each locating recess.  
     
     
         25 . A screening panel as claimed in  claim 24  where in the grooves are semi-circular in shape such that, when respectively brought into register with similar semi-circular grooves on adjacent panels, they and the similar grooves together define annular grooves around their associated locating recesses, for receiving complementary annular securing protrusions on the support frame.  
     
     
         26 . A screening panel as claimed in  claim 16 , which is of resiliently deformable material selected from the group consisting of plastics materials and elastomeric materials.  
     
     
         27 . A screening panel as claimed in  claim 26  wherein the plastics material is polyurethane and the elastomeric material is rubber.  
     
     
         28 . A screen support frame sub-assembly which includes 
 an elongate screen support member of a screen support frame, the screen support member having connecting formations; and    a plurality of securing devices releasably connected to the connecting formations of the screen support member;    each securing device including a body portion having a connecting formation for connection to the connecting formations on the screen support member to render the screening element securing device releasably connected to the screen support member; and    a locating formation, provided on the body portion, for engagement with a complementary formation on a screening element to locate the screening element on the screen support frame.    
     
     
         29 . A screen support frame which includes a plurality of screen support frame sub-assemblies spaced from and parallel to one another and spaced apart from one other by a plurality of spacer bars, each sub-assembly including 
 an elongate screen support member having connecting formations; and    a plurality of securing devices releasably connected to the connecting formations of the screen support member;    such securing device including a body portion having a connecting formation for connection to the connecting formation on the screen support member to render the screening element securing device releasably connected to the screen support frame; and    a locating formation, provided on the body portion, for engagement with a complementary formation on a screening element to locate the screening element on the screen support frame.    
     
     
         30 . A screening arrangement which includes a screen support frame and a plurality of screening elements secured thereon, each screening element having a peripheral frame defining an opening across which a plurality of mutually spaced ribs extend to define a screening surface, the peripheral frame having an upper surface on the same side of the screening element as the screening surface, a lower surface on its side opposite its upper surface and an outer peripheral surface interconnecting the upper and lower surfaces, the peripheral frame being provided on its lower surface with locating formations for engagement with complementary locating formations on a screen support frame to locate the screening element on the screen support frame, the screen support frame including a plurality of screen support frame sub-assemblies spaced from and parallel to one another and spaced apart from one other by a plurality of spacer bars, each sub-assembly including 
 an elongate screen support member having connecting formations; and    a plurality of securing devices releasably connected to the connecting formations of the screen support member;    each securing device including 
 a body portion having a connecting formation for connection to the connecting formation on the screen support member to render the screening element securing device releasably connected to the screen support member; and  
 a locating formation, provided on the body portion, for engagement with a complementary formation on the screening element to locate the screening element on the screen support frame.  
   
     
     
         31 . A screening arrangement as claimed in  claim 30  wherein the peripheral frame of the screening element is provided on its lower surface with separate securing formations for engagement with complementary separate securing formations on the screen support frame to secure the screening element against displacement on the screen support frame.