Abstract:
A screen panel assembly is used with a screening machine. The screen panel assembly includes first and second generally planar screen panels and a coupling between the first and second screen panels that includes latching mechanisms to temporarily secure the screen panels together. An overlap region between the first and second screen panels permits lifting of the second screen panel by a lifting force exerted upon the first screen panel while inhibiting the passage of material being screened between the two adjacent screen panels.

Description:
[0001]    This is a continuation in part of U.S. patent application Ser. No. 12/261,117, filed Oct. 30, 2008 and hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to screening machines or separators of the type used to separate or classify mixtures of solid particles of different sizes. 
         [0003]    In screening machines or separators of the type described, a screen (which may be woven, an aperture plate or another design) is mounted and pre-tensioned in what is often called a “screen pane” or “screen deck” that includes a supporting peripheral frame around the perimeter of the screen. The terms “screening machine” and “separator” and respective derivatives thereof are herein used interchangeably. A main housing of the screening machine supports one more of the screen panels, as well as agitating structures that shake or vibrate the solids deposited on the screen panels. 
         [0004]    The screen panels are often removed from the screening machines for cleaning, replacement, readjustment or installation of a screen of a different mesh size or the like. In large commercial screening machines, the screen panels are inserted through and removed from a longitudinal end of the machine. In accordance with this movement of the screen panels, sufficient space must be devoted near the end of the machine, such that the generally horizontal screen panels may be inserted into and removed from the housing of the screening machine. Moreover, screen panels in large commercial screening machines tend to be relatively large, making their insertion and removal difficult or awkward at best, especially for a sole operator in tight working conditions. 
         [0005]    Many machines of this type are used to separate particulate material which, over time, often clogs or blocks the screen mesh. Commonly, an agitating mechanism is included in the machine to unblock the mesh by dislodging the clogging material. Often, the agitating mechanism is a number of balls captured by a ball tray and accessible to the screen mesh. In large commercial screening machines, the agitating structures may be also inserted and removed respectively through the end of the machine, as described above with respect to the screen panels, thereby presenting similar space requirements. Moreover, known agitating structures tend to be large and relatively heavy, making their insertion into and removal from the housing of the screening machine a particularly difficult and work-intensive task for the operators involved. 
         [0006]    It is evident, therefore, that a screening machine and screening machine components are needed that address these and other known problems associated with conventional screening machines. 
       SUMMARY OF THE INVENTION 
       [0007]    These and other shortcomings in the prior art have been addressed in various embodiments of this invention. In a first embodiment, a screen assembly is provided for use with a screening machine. The screen assembly includes first and second generally planar screen panels and a coupling between the first and second screen panels that includes a pair of latches on opposite side edges of the screen panels. The coupling may include an overlap region between the first and second screen panels that is engageable to thereby permit lifting of the second screen panel by a lifting force exerted upon the first screen panel. The first and second screen panels may be juxtaposed to one another along respective confronting end portions thereof, and a seal member is disposed between the end portions. The seal member may be positioned between a contoured feature on a top face of one of the screen panels and end edge of the other screen panel. The first and second screen panels may each include pre-tensioned screens mounted within a frame of the screen panel. The first and second screen panels may be substantially identical and interchangeable with one another. 
         [0008]    In yet another embodiment, a screening machine includes a main housing and a screen panel assembly. The screen panel assembly has first and second generally planar screen panels and a coupling between the screen panels that is configured to permit movement of the first and second screen panels by a force that is exerted upon the first screen panel. The coupling in one embodiment includes a pair of latches on opposite side edges of the screen panels. The screening machine also includes an agitating structure that is supported by the main housing and which is configured to hold a plurality of agitating elements from moving material that is held by the screen panel assembly. 
         [0009]    The agitating structure may include a stopping element for restricting movement of the screen panel assembly relative to the agitating structure. At least one of the first and second screen panels may include a limiting tab that is engageable with the stopping element for selectively restricting movement of the first and second screen panels relative to the agitating structure. The agitating elements may include balls. 
         [0010]    In another embodiment, a method is provided for moving screening components relative to a main housing of a screening machine. The method includes applying a force on a first of two generally planar screen panels, with such force moving the two screen panels relative to the main housing. A seal is positioned relative to overlapping portions of the two screen panels, and the first screen panel is moved relative to the other screen panel. 
         [0011]    In embodiments having a screen panel assembly that is made up of two or more generally planar screen panels, insertion and removal of the screen panel assembly respectively into and out of the main housing of the screening machine is greatly facilitated. Similarly, in embodiments having an agitating structure that includes segmented co-planar trays, insertion and removal of the agitating structure in conjunction with the screen panels is likewise facilitated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a partially broken-away perspective view of a screen panel assembly being inserted into a screening machine in accordance with one embodiment of this invention; 
           [0014]      FIG. 2  is a perspective view of a pair of screen panels according to one embodiment of this invention; 
           [0015]      FIG. 3  is an enlarged partially broken-away view of the screen panels of  FIG. 2  taken along line  3 - 3  of  FIG. 2 ; 
           [0016]      FIG. 4  is an enlarged partially broken-away view of the screen panels of  FIG. 2  taken along line  4 - 4  of  FIG. 2 ; 
           [0017]      FIG. 5  is an enlarged partially broken-away view of the screen panels of  FIG. 2  taken along line  5 - 5  of  FIG. 2 ; 
           [0018]      FIG. 6  is an enlarged partially broken-away view of the screen panels of  FIG. 2  taken along line  6 - 6  of  FIG. 2 ; 
           [0019]      FIG. 7  is an enlarged partially broken-away perspective view of the latching mechanism joining adjacent screen panels of one embodiment of this invention; and 
           [0020]      FIGS. 8A-8B  are enlarged perspective sequential views of the interaction between the screen panels and ball tray of one embodiment of this invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    With reference to the figures, and more particularly to  FIG. 1 , a screening machine or separator  10  includes a main housing  12  having an access opening  14  located at a longitudinal end of the housing  12  for inserting and removing screening components such as a screen panel assembly  16  and an agitating structure  18  cooperating with the screen panel assembly  16  to segregate solids or other material (not shown) deposited on the screen panel assembly  16 . 
         [0022]    With reference to  FIGS. 1-2 , the screen panel assembly  16  of this exemplary embodiment is in the form of a segmented assembly that includes a first, leading screen panel  20  and a second, trailing screen panel  22  that are substantially identical to and interchangeable with one another. It is contemplated that the screen panel assembly  16  may instead have any number of screen panels other than two including, without limitation, a single screen panel, and still fall within the scope of this invention. Each of the screen panels  20 ,  22  includes a pre-tensioned screen  24  supported about the respective perimeters of the screens by a frame  26  and further includes a top face  28  and an opposite bottom face  30 . The screen panels  20 ,  22  each have spaced longitudinal leading and trailing ends  32 ,  34  and spaced lateral sides  36  and are engageable with one another along adjacent ends to define an overlap a region  38 . The screen panels  20 ,  22  are generally symmetric about a longitudinal center line. 
         [0023]    The screen mesh material is pre-tensioned and mounted between the screen frame according to one embodiment of the screen panel according to this invention and secured to the frame via a cured or baked on enamel around the perimeter of the screen surface of the screen panel. Alternatively, epoxies or other materials may be utilized to secure the pre-tensioned screen material to the frame. 
         [0024]    The overlap region  38  includes a seal member  40  mounted to one of the screen panels and prevents or at least minimizes the likelihood of material deposited on the screen panels  20 ,  22  from falling onto the underlying agitating structure  18 . 
         [0025]    In this exemplary embodiment, the agitating structure  18  is in the form of a segmented tray assembly having multiple, generally coplanar trays  42  that are also engageable with one another through a tray coupling (not shown). Additional details of one embodiment of the agitating structure  16  are detailed in co-pending patent application Ser. No. 12/261,117. Each of the trays  42  in this exemplary embodiment is partitioned into several compartments  44  ( FIG. 1 ). Longitudinal by extending lips  46  of each of the screen panels  20 ,  22  engage respective side walls  48  of the trays  42  and thereby determine a position of the screen panels  20 ,  22  relative to the trays  42  when these components are engaged with one another within the main housing  12  ( FIG. 1 ). Each of the longitudinal lips  46  extends only partially along the respective length of the associated screen panel  20 ,  22  to define a notch  50  between each of the lips  46  and a stopping element in the form of a limiting tab  52 . Each tray  42  also includes a flange  54  projecting vertically adjacent the lips of the screen panels and a longitudinal, generally horizontal projection  56 . 
         [0026]    It is contemplated, however, that an alternative agitating structure may have other shapes and/or include any number of trays other than the two trays of this exemplary embodiment. Such alternatives include, without limitation, an agitating structure having a single tray rather than a segmented tray assembly. Each of the individual trays of the illustrated embodiment includes several compartments  44  that hold agitating elements that move and thereby vibrate the solids deposited on the screen panel assembly  16 . The agitating elements, although not shown, may for example and without limitation include balls made of metal, plastic or other suitable material and are held within the compartments  44 . The agitating elements are supported by a support screen  45  and confined in the compartments  44  by partition walls  47  defining the compartments  44 . 
         [0027]    Referring to  FIGS. 1 and 2 , exemplary screen panels  20 ,  22  according to one embodiment of this invention are shown. Each screen panel  20 ,  22  is substantially identical to each other. The frame  26  of each screen panel includes the downwardly turned lip  46  extending longitudinally on each lateral side edge of the screen panel  20 ,  22 . The lip  46  includes the tab  52  having a generally sloped leading edge  58  and a generally vertically oriented trailing edge  60  adjacent to the notch  50 . 
         [0028]    The adjacent screen panels are joined together by a coupling  62  which in one embodiment includes one or more latching mechanisms  64 . One example of the latching mechanism  64  is shown particularly in  FIGS. 1 ,  2  and  7  is an over-center draw latch. One component of the latching mechanism  64  is a receiving hook  66  on the leading end  32  of each screen panel  20 ,  22 . The receiving hook  66  projects from a base portion  68  and is mounted to the lip  46  via mechanical fasteners  70 , two of which are shown in  FIGS. 1 ,  2  and  7  as bolts, although other mounting mechanisms may be utilized. The base portion  68  is mounted via the bolts  70  to the lip  46  so that the hook  66  is juxtaposed to the adjacent, leading screen panel  20 . On the adjacent screen panel, a latch base  72  of the latching mechanism  64  is likewise mounted via a pair of mechanical fasteners  70  such as bolts to the downwardly turned lip  46 . A generally rectangular-shaped member bail member  74  is pivotally coupled to a latch body  76  which is similarly pivotally coupled to the latch base  72  as is well known according to standard over-center draw latch design. Two latching mechanisms  64  are provided for each pair of adjacent screen panels  20 ,  22 , one on each opposite lateral side edge according to one embodiment of this invention. The latching mechanisms  64  draw the confronting adjacent longitudinal ends  32 ,  34  of the screen panels  20 ,  22  together. 
         [0029]    As shown in  FIGS. 1-7 , the leading longitudinal end  32  of each screen panel  20 ,  22  includes a contoured edge  78  with a generally linear central portion  80  bounded on each end by shoulder portions  82 . The contoured leading edge  78  of each screen panel  20 ,  22  is shaped and configured to mate with a contoured trailing edge  84  of each screen panel which includes a generally linear central portion  86  bounded on each end by jog portions  88 . Each jog  88  is configured to mate with the adjacent shoulder  82  of the adjacent screen panel. The leading and trailing contoured edges  78 ,  84  of the screen panels  20 ,  22  are positioned proximate the top face  28  of each screen panel. However, while the contoured leading edge  78  of each screen panel  20 ,  22  is at a distal end of the respective screen panel, the contoured trailing edge  84  of each screen panel is recessed relative to the distal edge of the screen panel such that a ledge  90  projects forwardly at a recessed level relative to the top face  28  along a substantial portion of the trailing end  34  of the screen panel  20 ,  22 . 
         [0030]    The frame  26  of each screen panel  20 ,  22  along the leading end  32  thereof includes a hem  92  offset or recessed from the distal edge of the screen panel. The hem  92  includes a jaw  94  which presents an opening facing the leading edge  32  of the screen panel  20 ,  22 . The jaw  94  is sized and configured to receive therein the ledge  90  along the trailing end  32  of the leading screen panel  20  so as to provide one aspect of the coupling  62  between the adjacent screen panels  20 ,  22 . The ledge  90  mating with the hem  92  and jaw  94  of the leading screen panel  20  provides an overlap portion  96  between the adjacent screen panels  20 ,  22  as shown particularly in  FIGS. 3 and 4 . The cross-sectional view of  FIG. 4  shows the ledge  90  seated within the jaw  94  of the trailing screen panel  22 . The seal member  40  is mounted along the contoured edge  84  of the trailing end  32  of the screen panel  20  atop the ledge  90 . When the adjacent screen panels  20 ,  22  are joined together, the seal member  40  is compressed between the contoured edges  78 ,  84  as shown in  FIGS. 3 and 4 . 
         [0031]    Another aspect of the coupling  62  between the adjacent screen panels  20 ,  22  according to various embodiments of this invention are lugs  98  which extend from the ledge  90  along the trailing end  34  of the screen panel  20 . Two such lugs  98  are shown in the drawings. In particular, in  FIGS. 5 and 6 , one of the lugs  98  is shown as a folded under extension from the ledge  90 . Each lug  98  is seated within a seat  100  formed in a gap of the hem  92  of the leading edge  32  of the trailing screen panel  22 . The seats  100  are particularly shown in  FIGS. 1 and 2  and are spaced across the width of the screen panel. The lug  98  positioned within the seat  100  is likewise shown in cross-sectional view of  FIG. 3 . The combination of the lugs  98  and the seats  100  on the adjacent mating ends  32 ,  34  of the screen panels  20 ,  22  helps to center the screen panels in a lateral direction relative to one another as well as providing an additional mechanism for coupling the panels. 
         [0032]    With reference to  FIGS. 8A and 8B , the functionality of the limiting tabs  52  is described in further detail.  FIGS. 8A-8B  show an exemplary motion of the screen panel assembly  16  relative to the agitating trays  42 . As the screen panel assembly  16  is pushed in the general direction of arrow  102 , the screen panel assembly  16  is moved upward relative to the underlying agitating structure  18 . This motion of the screen panel assembly  16  is such that the lip  46  of the screen panel  20 ,  22  rides over the flange  54  of the agitating structure  18 . Further motion of the screen panel assembly  16  requires lifting of the leading screen panel  20  in the general direction of arrow  102  ( FIG. 8A ) as the leading sloped edge  58  rides over the flange  54  results in the flange  54  seating in the notch  50 . Notably, the restriction of the removing motion of the first screen panel  40  provided by the engagement of the trailing edge of the limiting tab  66  with the flange. A natural stopping point at which the operator is signaled to disengage the first screen panel  40  from the second screen panel  42  is indicated as the flange enters the notch and the screen panel dips downwardly onto the tray. 
         [0033]    Removing motion of the screen panel assembly  20  is accomplished in removing motion opposite from arrow  102 , moving away from the main housing  12  and along with the agitating structure  16 . Movement of the screen panel with the pulling force exerted on the screen panel opposite from arrow  102  engages the trailing edge  60  of the tab  52  with the flange  54 . As the screen panel is pulled in this direction, the tab  52  results in pulling (i.e., removing motion) of the agitating structure  18  from the housing. 
         [0034]    In operation, when engagement of the limiting tab  66  with the flange of the agitating structure  30  occurs, the first screen panel  40  is disengaged from the second screen panel  42 . More specifically, the first screen panel  40  is first moved toward the main housing  14  ( FIGS. 1-2 ) in the general direction of arrow  122  until the tab  112  engages the flange. The operator then proceeds to tilt the first screen panel  40  relative to the second screen panel  42 , and then to remove the first screen panel  40  away from the second screen panel  42  in the general direction of arrow  70 . 
         [0035]    From the above disclosure of the general principles of this invention and the preceding detailed description of at least one embodiment, those skilled in the art will readily comprehend the various modifications to which this invention is susceptible. Therefore, we desire to be limited only by the scope of the following claims and equivalents thereof.