Abstract:
A screening module retaining member  10  includes a body member  12  defining a passage  16 . A retaining element  14  is displaceably arranged in the passage  16 . The retaining element  14  is displaceable between a first, non-retaining position in which the retaining member is accessible from a first end of the body member  12  and a second, retaining position in which the retaining element  14  is received within the passage  16  and acts on at least a part  20  of the body member  12  for retaining the body member  12  in position relative to a component of a screen deck. A locating arrangement  22  is associated with the first end of the body member  12  for locating a screening module relative to the screen deck and for inhibiting lateral movement of the screening module relative to the body member  12.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Australian Provisional Patent Application No 2004905590 filed on 27 Sep. 2004, the contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     This invention relates to screening systems. More particularly, the invention relates to a screening module retaining member and to a screening module assembly including such retaining member. 
     BACKGROUND TO THE INVENTION 
     Screening systems are used for classifying ores. These screening systems use foraminous screening members which pass material of a predetermined size and block material of larger size. 
     The screening members are removably attached to a screen deck as they wear rapidly and need to be replaced. Various forms of attachment are used for attaching screening members to the screen deck. These forms of attachment include rails, pins, or other attachment elements which releasably retain the screen members on the screen deck. 
     One problem with these different arrangements is that, if the screen deck is configured to have screening members with an attaching system of a first type attached to the screen deck, the screen deck cannot be used with screening members of a type having a different attaching system. 
     In certain situations, the means by which the screening members are attached to the screen deck stand proud of an upper surface of the screening members. A problem with this arrangement is that it reduces the screening area of the screening members and impedes flow of material over the upper surfaces of the screening members. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, there is provided a screening module retaining member which includes: 
     a body member defining a passage; 
     a retaining element displaceably arranged in the passage, the retaining element being displaceable between a first, non-retaining position in which the retaining member is accessible from a first end of the body member and a second, retaining position in which the retaining element is received within the passage and acts on at least a part of the body member for retaining the body member in position relative to a component of a screen deck; and 
     a locating arrangement associated with the first end of the body member for locating a screening module relative to the screen deck and for inhibiting lateral movement of the screening module relative to the body member. 
     The body member may be a moulding of a resiliently flexible material. For example, the body member may be a moulding of a polymeric material such as a polyurethane material. 
     The body member may comprise a boss defining the first end with an engaging assembly extending from, and formed integrally with, the boss, a free end of the engaging assembly defining a second end of the body member. The passage may be an open passage extending from the first end of the body member to the second end of the body member and, when the retaining element is in its first position relative to the body member, a portion of the retaining element extends outwardly from the first end of the body member. 
     The engaging assembly may comprise a plurality of engaging elements. The engaging elements may be interconnected. Adjacent engaging elements may be interconnected by webbing which defines a zone of weakness between the adjacent engaging elements. 
     The passage may define a first holding formation for holding the retaining element in its first position and a second holding formation, spaced from the first holding formation, for holding the retaining element in its second position. Each of the first holding formation and the second holding formation may be in the form of a radially outwardly extending circumferential groove formed in a wall of the passage. 
     The retaining element may include a complementary structure, in the form of a circumferential rib, which is received in the first holding formation when the retaining element is in its first position and in the second holding formation when the retaining element is in its second position. 
     In one embodiment of the invention, the locating arrangement may be in the form of a radially outwardly extending lip defined proximate the first end of the body member which engages a complementary recess of the screening module. In addition, an opening of the passage at the first end of the body member, after the retaining element has been displaced to its second position, may be configured to receive a locating member of the screening module for inhibiting lateral movement of the screening module relative to the body member and to the screen deck. 
     In another embodiment of the invention, the locating arrangement may comprise at least one clip-like formation which stands proud of the first end of the body member to be engaged by a complementary clip-like formation of the screening module for releasably attaching the screening module to the screen deck and for inhibiting lateral movement of the screening module relative to the retaining element and the screen deck. 
     According to a second aspect of the invention, there is provided a screening assembly which includes: 
     at least one retaining member, as claimed in any one of the preceding claims; and 
     at least one screening module releasably attachable to the retaining member, the screening module including at least one complementary formation for engaging the locating arrangement of the at least one retaining member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention are now described by way of example with reference to the accompanying drawings in which: — 
         FIG. 1  shows a three dimensional, exploded view of a screening module retaining member, in accordance with an embodiment of a first aspect of the invention; 
         FIG. 2  shows a plan view of the retaining member of  FIG. 1 ; 
         FIG. 3  shows a bottom view of the retaining member of  FIG. 1 ; 
         FIG. 4  shows a side view of the retaining member of  FIG. 1 ; 
         FIG. 5  shows a sectional end view of part of a screening assembly in accordance with a first embodiment of a second aspect of the invention, the side view of the retaining member of the assembly being taken along line V-V in  FIG. 4  of the drawings; 
         FIG. 6  shows an end view of the screening assembly; 
         FIG. 7  shows, on an enlarged scale, the circled part of the screening assembly of  FIG. 6 ; 
         FIG. 8  shows an end view of a screening assembly in accordance with a further embodiment of the second aspect of the invention; and 
         FIG. 9  shows a sectional end view of a part of the screening assembly of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring to the drawings, reference numeral  10  generally designates a screening module retaining member in accordance with an embodiment of the invention. The retaining member  10  includes a body member  12  and a retaining element  14  displaceably arranged in a passage  16  of the body member  12 . 
     As shown most clearly in  FIG. 5  of the drawings, the body member  12  of the retaining member  10  includes a boss  18  with an engaging assembly  20  extending from the boss  18 . 
     The body member  12  also defines a locating arrangement  22  for locating a screening module  24  relative to a screen deck  26  ( FIG. 6 ) and the retaining member  10 . 
     The engaging assembly  20  comprises a plurality of discrete engaging elements  28  arranged in a substantially petaloid fashion. Adjacent engaging elements  28  are separated from each other by webbing defining a zone of weakness in the form of a groove or a slot  30  to facilitate insertion of the engaging assembly  20  into a rail  32  of the screen deck  26 , as will be described in greater detail below. 
     The passage  16  defines a first holding formation, in the form of a radially outwardly extending groove  34 , proximate its first end and a second such holding formation, also in the form of a groove  36 , inwardly of its second end. 
     The retaining element  14  is a substantially cylindrical spigot-like member, or pin,  38  having a radially outwardly extending circumferential rib  40  proximate a second end of the pin  38 . When the retaining element  14  is in its first position relative to the body member  12 , part of the pin  38  stands proud of an upper surface  42  at a first end of the body member  12  with the rib  40  received in the first groove  34 . This enables a first end  44  of the pin  38  to be engaged by an installation tool (not shown) for driving the pin  38  from its first position to a second, displaced position as shown in  FIG. 5  of the drawings in which the rib  40  of the retaining element  14  is received in the second groove  36 . The Applicant envisages using a special installation tool (not shown) configured to displace the pin  38  from its first position to its second position in which the rib  40  is received in the second groove  36  of the passage  16  but not to drive the pin  38  too far into the passage to a position where the rib  40  would overshoot the second groove  36 . 
     Thus, in use, the retaining member  10  is provided with the pin  38  in its first position. The body member  12  is inserted through an opening  46  in the rail  32  of the screen deck  26 . In this regard, it will be noted that the openings  46  are arranged at regularly spaced intervals along each rail  32  of the screen deck and a retaining member  10  is received in each opening  46 . Once the retaining members  10  have been placed in position on the rails  32  of the screen deck, the pin  38  of each retaining member  10  is driven to the position shown in  FIG. 5  of the drawings. This causes the engaging elements  28  of the engaging assembly  20  of the body member  12  to splay slightly outwardly securely locking the body member  12  to the rail  32 . In this position, the boss  18  sits on a horizontal surface  48  of each rail  32 . The locating arrangement  22  stands proud of the surface  48  of the rail  32 . A feature of the retaining member  10  is that, to remove the retaining member  10  from the rail  32 , the pin  38  is driven all the way through and out of the second end of the passage  16 . This releases the engaging elements  28  allowing the body  12  to be withdrawn from the opening  46  in the rail  32 . Hence, there is no need to replace or change the rail  32  when it is necessary or desired to replace the retaining members  10 . 
     Referring once again to  FIG. 5  of the drawings, it is to be noted that a side  50  of the screening module  24  has a receiving zone or recess  52  which has a shape that approximates half of the boss  18  of the retaining member  10 . The end  50  of the screening module  24  is thus clipped into position over the boss  18  of the body member  12  of the retaining member  10 . A downwardly projecting tab  54  at the side  50  of the screening module  24  is received in the first end of the passage  16 . This assists in securing the screening module  24  laterally relative to the retaining member  10  and to the rail  32  of the screen deck  26 . The surface  42  defines a land against which a horizontal surface  56  of the recess  52  at the side  50  of the screening module bears which assists in stabilising the module  24  relative to the retaining members  10 . 
     Adjacent screening modules  24  are arranged in side-by-side abutment, as shown in  FIG. 6  of the drawings, with the side  50  of one screening module  24  overlying one half of the boss  18  of the retaining member  10  with the other side of the adjacent screening module  24  overlying the other half of the boss  18  of the retaining member  10 . The tabs  54  of the abutting sides  50  of the screening modules  24  are received in the passage  16  of the retaining member  10  and abut against each other to assist in lateral retention of the screening modules  24 . 
     Thus, a screening system  60  comprising a plurality of the retaining members  10  received in rails  32  of the screen deck  26  with screening modules  24  secured to the retaining members  10  is provided. 
     Referring to  FIGS. 8 and 9  of the drawings, yet another embodiment of a screening system  60  is illustrated. With reference to  FIGS. 1 to 7  of the drawings, like reference numerals refer to like parts, unless otherwise specified. 
     In this embodiment of the invention, the retaining arrangement  22  of the boss  18  of the retaining member  10  includes a pair of opposed clip-like formations, or clips  62 , standing proud of the surface  42  of the boss  18 . These clips  62  are rectilinear and the boss  18  is square or rectangular as opposed to the circular boss  18  of the retaining member  10  shown in  FIGS. 1 to 7  of the drawings. 
     The retaining member  10  of the embodiment of the invention shown in  FIGS. 8 and 9  of the drawings is for use with a screening module  24  having a clip-like formation  64  running along each side  66  of the screening module  24 . Thus, in this embodiment of the invention, the screening module  24  is retained in position relative to the retaining member  10  by clipping engagement between the clips  62  of the retaining member  10  and the clip-like formation  64  of the screening module  24 . It will be appreciated that, with this arrangement, the clips  62  engaging with the clip-like formation  64  of each screening module  24  serve also to retain the screening module  24  laterally with respect to the retaining members  10  and, as a result, the screen deck  26 . 
     Although the body member  12  and retaining member  14  are moulded separately, prior to use the retaining element  14  is driven into its first position relative to the body member  12  and is retained in that position by the rib  40  engaging the groove  34  at the first end of the passage  16  of the body member  12 . The retaining member  10  is supplied in this configuration. As described above, once the body member  12  has been inserted into the hole  46  in the rail  32 , the retaining element  14  is driven into its second position where the rib  40  engages the groove  36  inwardly of the second end of the passage  16  of the body member  12  to hold the retaining element  14  in its second position relative to the body member  12 . 
     It is therefore an advantage of the invention that a retaining member  10  is provided with the retaining element  14  secured relative to the body member  12 . Hence, there is no necessity to locate a separate pin in order to insert and retain the retaining member in position relative to the rail  32 . It will be appreciated that screen decks  26  are often used in hostile environments and it is very easy to lose small, separate pieces. The provision of the retaining member  10  in accordance with an embodiment of the invention largely overcomes this problem. 
     It is a further advantage of the invention that a screening system  60  is provided which is more versatile in that, by use of the retaining member  10 , a screen deck  26  can be modified to accept screening modules  24  which are either of the pin-attaching type or of the rail/clip-attaching type. Hence, with the provision of the retaining member  10  screening modules  24  can be used with either a pin-type screen deck or a rail-type screen deck. 
     It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.