Abstract:
A diverter belt having translatable pushers with article-contacting rollers to push articles across the belt. Cam followers on the pushers follow guides under the belt along an upper carryway run to translate the pushers across the width of the belt along one or more transverse tracks.

Description:
BACKGROUND 
     The invention relates generally to power-driven conveyors and more particularly to pusher-type diverters. 
     Article diverters, such as shoe sorters, are used to translate articles across the width of a conveyor as the conveyor transports the articles in a conveying direction. Typical shoe sorters include shoes, or pushers, that are driven laterally across the conveyor to push articles off one or both sides of the conveyor to one or more outfeed locations. In other article-diverting conveyors, the laterally driven pushers can be used to merge articles to the center of the conveyor and into alignment. Slat conveyors and modular conveyor belts are used as platforms for the pushers, which ride in tracks extending across the widths of the slats or belt modules. The pushers have depending structural elements that keep the pushers in the track or extend below to engage carryway guides that control the lateral positions of the pushers. The pushers are often ramped or have concavely curved lower skirts up which articles can ride when contacted by the pushers as they are driven along the track. In some cases the articles can ride up and over the pushers and not be aligned as required. 
     SUMMARY 
     One version of a conveyor belt embodying features of the invention comprises a top surface and an opposite bottom surface and a plurality of tracks extending across the conveyor belt. Pushers, which have article-contacting rollers above the top surface of the conveyor belt, are arranged to move along the tracks. 
     One version of a conveyor embodying features of the invention comprises a conveyor belt advanceable along an upper carryway run in a conveying direction and a diverter disposed below the bottom surface of the conveyor belt along the carryway run. The conveyor belt includes a top surface and an opposite bottom surface and a plurality of elongated tracks spaced apart in the conveying direction and extending across the conveyor belt. Pushers are arranged to translate along the elongated tracks. The pushers include cam followers that extend below the bottom surface and freely rotatable article-contacting rollers that extend above the top surface. The diverter has a guide surface contacting the cam followers to translate the pushers across the conveyor belt as it advances in the conveying direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1C  are, respectively, top, front elevation, and bottom views of a roller-pusher diverter belt module embodying features of the invention, including left- and right-hand slots with a pusher in each; 
         FIGS. 2A-2D  are, respectively, isometric, side elevation, front elevation, and top plan views of one version of a snap-in roller pusher for a diverter belt module as in  FIGS. 1A-1C ; 
         FIG. 3  is an elevation view of the pusher of  FIGS. 2A-2D  without the roller; 
         FIGS. 4A and 4B  are perspective and side elevation views of a diverter belt constructed of belt modules as in  FIGS. 1A-1C ; and 
         FIG. 5A  is a top plan view of a portion of the diverter belt of  FIGS. 4A and 4B  being guided by a diverting guide, and  FIG. 5B  is a top plan view of the diverting guide with the diverter belt removed for clarity. 
     
    
    
     DETAILED DESCRIPTION 
     One version of a pusher module for a conveyor belt is shown in  FIGS. 1A-C . The module  10  has two transverse tracks in the form of elongated slots  12 ,  13  that extend through the thickness of the module. A pusher  14  translates along the length of each slot. The slots  12 ,  13  in this example are shown aligned, of the same length, and elongated in the width direction of the module  10 . But the slots could be offset from each other in the conveying direction  16  and could be of different lengths. Or a module could be made with a single slot or more than two slots. 
     The pusher  14 , as also shown in  FIGS. 2A-D  and  3 , has an upper axle portion  18  and a lower cam follower portion  20  joined by an intermediate shank portion  22 . The upper axle portion  18  extends from a shoulder  24  that slides along the top conveying surface  26  of the module  10 . The narrow shank portion  22  extends through the slot  12 ,  13 . The lower cam follower portion  20  rides along the slot just below the bottom of the module&#39;s drive bar  28 . A roller  30  is rotatably mounted on the axle portion  18  received in a central bore  32  of the roller. The axle portion  18  defines a vertical axis  34  of rotation for the roller  30 . The axle portion  18  comprises a pair of prongs  36 ,  37  extending upward from the shoulder  24  at a proximal end to distal domed tabs  38 ,  39  with a maximum outer dimension greater than a maximum outer dimension of the prongs  36 ,  37  in a cross section perpendicular to the vertical axis  34 . The outer diameter of the distal domed tabs  38 ,  39  is greater than that of the central bore  32  to retain the roller  30  on the pusher  14 . The prongs  36 ,  37  are separated across a slot  40 . Together, the two prongs  36 ,  37  form a flexible split axle  35  that allows the roller  30  to be snapped in place and easily removed. The pairs of prongs  38 ,  39  in this example have half-moon cross sections with facing flat faces and outer circular curved bearing surfaces  41  on which the roller  30  rides. The outer bearing surfaces  41  of the two prongs  36 ,  37  lie on the same imaginary circular cylinder when the prongs are unflexed. 
     As shown in  FIG. 3 , the proximal bases of the prongs  36 ,  37  have slight bottom skirts  44 ,  45  that taper concavely from the outer bearing surfaces  41  to the shoulder  24  of the pusher  14 . The widening skirts  44 ,  45  elevate the roller  30  slightly above the shoulder  24  across a space  47  to eliminate frictional contact between the shoulder  24  and the bottom side face  46  of the roller, as shown in  FIGS. 1B and 4B . On insertion of the split axle  35  into the roller&#39;s bore  32 , the domed tabs  38 ,  39  are pushed toward each other into the intervening space  40  enough to enter the bore. The compressed split axle  35  is pushed through the bore  32  until the tabs exit the other end of the bore. The tabs  38 ,  39  spring outward by snap action upon clearing the bore  32  and retain the roller  30  in place on the relaxed split axle  35 . The roller  30  is easily removed by manually compressing the split axle  35  by pushing the two tabs  38 ,  39  toward each other until they fit in the bore  32 . Once the tabs  38 ,  39  are in the bore  32 , the roller  30  can be slid off the split axle  35 . 
     The pusher  14  less the roller  30  in this example is realized as a monolithic element homogeneously formed as a single piece by molding, for example. The height of the shank  22  is slightly greater than the thickness of the module  10  at the slot  12 ,  13 . The outer dimensions of the pusher  14  slightly above the top conveying surface  26  and slightly below the bottom surface  27  of the module are slightly greater than the width of the slot—enough to retain the pusher in the slot. The narrow portion  43  of the plastic module  10  between the slots  12 ,  13  and the first end  42  and shown hatched in  FIG. 1A  is flexed upward or downward to temporarily widen the slots to admit the pusher into place. Once the pusher  14  is in place, the narrow portion  43  is released, and the module  10  returns to its natural relaxed state retaining the pusher. Then the roller  30  can be snapped in place on the split axle  35 . 
     A portion of a diverter belt is shown in  FIGS. 4A and 4B . The belt  50  is constructed of rows  52  of belt modules  10  connected end to end at hinge joints  54  by hinge rods  57  received in aligned rod holes  58  through interleaved hinge elements  59  of adjacent belt rows. The belt  50  is driven by a female sprocket (not shown) with gullets receiving the belt&#39;s drive bars  28 . Although the belt  50  is shown with a single module  10  in each row  52 , a belt could be constructed of more than one module per row. 
     One example of a diverting unit usable with the diverter belt  50  is shown in  FIGS. 5A and 5B . The pushers  14  are translated as the belt  50  advances in the conveying direction  60  by a diverter unit  62  disposed below the conveyor belt and supported in the conveyor frame. In this example the diverter unit  62  includes two vertical guide surfaces  64 ,  65  on guide members  66 ,  67 . The guide members  66 ,  67  are mirror images of each other about the centerline  56  of the belt  50 . Each of the guide surfaces  64 ,  65  is stepped with four parallel segments  68 A-D extending in the conveying direction  60  joined to each other and to side rails  70 ,  71  by oblique segments  69 A-D. The downstream-most parallel segment  68 D is connected to a central beam  72  by a cross link  74 . The guide unit  62  is strengthened by cross members  76 . The entire diverter unit  62  may be molded or machined as a single monolithic piece to avoid crevices at joints that could harbor bacteria, dirt, and other contaminants and to eliminate snag points that could form at misaligned joints in a multi-piece design. In this example, the top surfaces  75  of the guide members  66 ,  67 , the side rails  70 ,  71 , the oblique segments  69 A-D, and the central beam  72  are coplanar. The top surfaces  77  of the cross members  76  and the cross links  74  are recessed at a level far enough below the plane of the top surfaces  75  of the guide members, the side rails, the oblique segments, and the central beam to avoid snagging the underside cam followers on the pushers. Other surfaces  79 ,  81  on the diverter unit are oriented oblique to the conveying direction to avoid snagging. The coplanarity of the top surfaces  75  provides for lower-pressure contact with the cam followers and allows the diverter unit  62  to serve as the carryway supporting the belt  50 . The diverter unit  62  could alternatively be divided into two monolithic halves about the centerline  56  of the belt. Or the guide members, the side rails, the oblique members, the central beam, and the cross members could be manufactured as separate pieces held together by tie rods to ensure coplanarity of the top surfaces. The central beam  72  of the diverter unit  62  is further shown with generous openings  78  for easier drainage and cleaning, as well as for reduced weight. 
     As shown in  FIG. 5A , the diverter unit  62  is used to center conveyed articles on the conveyor belt  50 . Before encountering the diverter  62 , the pushers  14  are typically positioned at home positions near the outside ends of the slots  12 ,  13 . As the pushers  14  encounter the first and longest oblique guide segments  69 A, they are moved a majority of the distance toward the centerline  56  of the belt  50 , but the orientation of the articles is skewed by the obliquely arranged pushers. Along the longer parallel segments  68 A-C, the pushers  14  are aligned in the conveying direction  60 . Each consecutive parallel segment  68 B-D downstream is closer to the centerline  56 . Each consecutive oblique diverting segment  69  B-D downstream is shorter in length and diverts a lesser distance inward. The stepped guide surfaces tend to bump conveyed articles, such as rectangular packages, straight, out of skew. Operating the pushers  14  to follow a stepped guide path, rather than a continuously curved guide path, centers conveyed articles while maintaining their original orientations. Downstream of the stepped centering portion, the diverter  62  has a pair of reset guides  80  that guide the pushers  14  back to their home positions near the outside ends of the slots  12 ,  13 . 
     Although the only one version of the roller pusher was described in detail, other versions are possible. For example, a one-piece axle with an enlarged roller-retaining head could be used instead of the split axle. The enlarged head could be unitarily formed as part of the axle or could be a separate piece that snaps or screws into a cavity at the distal top end of the one-piece axle to permit replacement of the roller. Other structures for retaining the roller are also possible. And although the roller pusher was shown in a modular conveyor belt, it could also be used in other kinds of diverter belts, such as slat conveyors. And the diverter belt could be used with diverter units other than the exemplary one shown in  FIGS. 5A and 5B .