Abstract:
A rodless system for a modular conveying belt where the studs are inserted into the pivot opening by transversally shifting the module with the studs in relation to the module with the pivot opening.

Description:
FIELD OF THE INVENTION 
   The present invention relates to modular belts for use in conveying systems. 
   BACKGROUND OF THE INVENTION 
   Modular belts are usually constructed from modules that are assembled in a bricklayed manner and hinged together with a pivot rod. A disadvantage of this design is the complexity of the assembly process, which is typically done manually. This complexity results in high assembly costs and an inventory needed for the large number of pivot rods. 
   Various attempts have been made to eliminate the pivot rods. The primary motivation for eliminating the pivot rods is to reduce cost. Most of the known rodless systems join the modules by clipped links. The clipped systems are sometimes promoted as being easier to assemble and easy to clean. 
   Most of the clipped systems use molded studs integrated into the link ends on one side of the module to act as a pivot pin. These studs are engaged (or snapped in) through a slotted link on the opposite side of the adjacent module and finally rest in the pivot bore. The slots or gaps, which are provided to introduce the studs into the link, may cause problems for cleaning. Residuals may be collected therein and are difficult to remove. 
   Accordingly, there is a need for a modular belt with a rodless hinge that overcomes the above mentioned shortcomings. 
   SUMMARY OF THE INVENTION 
   The present invention meets the above described need by providing a rodless system where the studs are inserted into the pivot opening by transversally shifting the module with the studs in relation to the module with the pivot bore. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: 
       FIG. 1A  is a bottom perspective view of a module according to the present invention; 
       FIG. 1B  is a top plan view of an alternate embodiment of the present invention; 
       FIG. 1C  is a cross-sectional view taken along lines  1 C- 1 C of  FIG. 1B ; 
       FIG. 2  is a perspective view of a pair of adjacent modules prior to the joining of the modules to form a belt; 
       FIG. 3  is a perspective view of the modules of  FIG. 2  in an intermediate step; 
       FIG. 4  is a perspective view of the modules of  FIG. 2  illustrating a further step in the assembly process; 
       FIG. 5  is a bottom perspective view of a modular belt according to the present invention as it articulates about a sprocket; 
       FIG. 6  is a top plan view of a portion of a belt according to the present invention; 
       FIG. 6A  is a bottom plan view of the portion of the belt shown in  FIG. 6 ; 
       FIG. 7  is a perspective view of a portion of a module with a stud positioned in one of the openings; and, 
       FIG. 8  is a bottom plan view of an alternate embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1A-7  generally and initially to  FIG. 1A , a belt module  10  has a first side edge  13  and a second side edge  16  disposed opposite from the first side edge  13 . The module  10  has a bottom surface  19  that extends from a leading edge  22  to a trailing edge  25 . The bottom surface  19  includes a first curved portion  28  extending from the leading edge  22  to a central portion  31 . With respect to the orientation of  FIG. 1A , a rib  34  extends upward from the central portion  31  between the first side edge  13  and the second side edge  16 . The rib  34  extends transverse to the direction of belt travel indicated by arrow  35 . The central portion  31  extends to a second curved portion  37  that extends to the trailing edge  25 . 
   A first plurality of link ends  40  extend from the bottom surface  19  in the direction of belt travel. The link ends  40  have a bottom surface  43 ; end surfaces  46 ,  49 ; side surfaces  52 ,  55 ; and a top surface  58  ( FIG. 2 ) that is coplanar with a top surface  61  of the module  10 . Each of the link ends  40  has a stud  64  extending therefrom in the transverse direction. The stud  64  may be cylindrical and may have an angled face  67  at its distal end. As shown in  FIG. 1A , the end surface  46  is narrower than end surface  49  and the bottom surface  43  has a thinner portion  44  adjacent end surface  46  and a wider portion  47  adjacent to end surface  49 . Side surface  52  has a recessed portion  70 . 
   A second plurality of link ends  73  extend from the bottom surface  19  in a direction opposite to the first link ends  40 . The second link ends  73  have spaces  76  disposed between adjacent link ends  73 . The link ends  73  are offset from link ends  40  such that the link ends  40  of an adjacent module  10  fit into the spaces  76  between link ends  73 . By intercalating the link ends  40 ,  73  of adjacent modules  10  as shown in  FIGS. 2-5 , a belt  80  ( FIG. 5 ) is formed. The belt  80  has a width that is formed by one module  10  in each row. The belt  80  could also be formed with multiple modules per row and assembled in bricklayed fashion as will be evident to those of ordinary skill in the art based on this disclosure. 
   Returning to  FIG. 1A , the link ends  73  have openings  83  for receiving the studs  64  on adjacent link ends  40  when the modules  10  are intercalated as discussed in greater detail below. The second link ends  73  have a bottom surface  86 ; end surfaces  89 ,  92 ; and side surfaces  95 , 98 . The bottom surface  86  has a wider portion  99  at the distal end and has a narrower portion  101  at the end that connects to the central portion  31 . The side surface  95  curves inward around the opening  83 . A first portion  103  extends inward and around opening  83  where it joins with a second portion  105 . The module  10  may be molded in one piece from a plastic compound that is modified with additives to reduce friction and wear. For example, polytetrafluorethylene (TEFLON) may be added to the base plastic material. As an alternative and as shown in  FIGS. 1B-1C , the module body and the studs may be made from different materials. Studs  66  are constructed of a different material and may be inlayed in the mold prior to the module  68  being molded. 
   Turning to  FIG. 2 , link end  40  has a first width W 1  at the top surface  58 . The link end  40  curves from the top surface  58  along the end surface  49 . The end surface  49  becomes narrower on the right hand side (with respect to the orientation of  FIG. 2 ) where an edge  108  curves inward. Accordingly, the width W 2  at the bottom of the end surface  49  is less than width W 1 . On the opposite side of the link end  40 , the stud  64  extends in the transverse direction. When the module  10  is angled with respect to the adjacent module  10  as shown in  FIG. 2 , the link end  40  and stud  64  can be inserted into the space  76  between the link ends  73  on the adjacent module  10 . The curvature along the right hand edge  108  of link  40  provides clearance for inserting the link end  40  and stud  64  in the direction of arrow  111 . 
   In  FIG. 3 , the next step of the assembly process is shown. The link end  40  is inserted into the space between adjacent link ends  73  until the stud  64  is aligned with the opening  83  in the link end  73 . As shown, the curved edge  108  of the link end  40  nests with the curved side surface  95  of link end  73  to provide clearance for the stud  64 . Once the stud  64  is aligned with the opening  83 , the first module  10  is moved transversally with respect to the second module  10  in the direction of arrow  129  such that the stud  64  is received in the opening  83 . 
   Turning to  FIG. 4 , once the stud  64  is inserted into the opening  83 , the module  10  is rotated about the pivot point in the direction of arrow  114  until the adjacent modules  10  form a belt with a coplanar top surface as best shown in  FIG. 6 . 
   In  FIG. 5 , the assembled belt  80  is shown as it traverses a sprocket (not shown). When the modules  10  are rotated into position to form a belt  80 , the side edges  84 ,  85  of intercalated link ends  40 ,  73  provide an obstruction that prevents any relative lateral motion between adjacent link ends  40 ,  73 . Accordingly, the stud  64  is prevented from moving out of the opening  83  and the adjacent modules are pivotally connected and able to rotate with respect to each other about the pivot axis established by the studs  64 . As shown in  FIG. 5 , the curvature of the link ends  40 ,  73  also provides dynamic hinge gaps  119  that become larger as the belt passes over a sprocket. The dynamic hinge gaps  119  provide for better cleaning of the hinge area. Also, the design of module  10  provides large hinge openings  120  when the belt  80  passes over a sprocket. 
   In  FIG. 6 , a top view of a belt formed according to the present invention is shown. The belt is shown in a flat position with a single module  10  in each row  150 . It will be evident to those of ordinary skill in the art based on this disclosure that the belt could also be formed with multiple modules per row and assembled in a bricklayed fashion. 
     FIG. 6A  is a bottom view of the belt shown in  FIG. 6 . The dynamic hinge gaps  119  are much smaller than in  FIG. 5  and the gaps  120  around the hinge area are closed. The link ends  40 ,  73  are not capable of relative lateral movement in this position and therefore the studs  64  remain in position in openings  83 . 
   Turning to  FIG. 7 , the openings  83  may be provided with an oblong shape to provide better access for cleaning fluids. As shown, the stud  64  may fit into a round portion of the opening  83 , and the remaining portion  124  is open. 
   In  FIG. 8 , an alternate embodiment of the present invention is shown. Module  200  is intended to improve the cleanability of the belt where belt strength can be reduced. The link end pairs  202  are spaced apart by a distance D 1 . Increasing the space between the pairs necessarily reduces the number of link pairs  202  in a belt, which produces a free space  204  between the link pairs  202  that is easier to clean. This arrangement is particularly advantageous because, in contrast to a conventional pivot rod arrangement, the rodless design does not have a length of rod crossing the open space  204  between the link pairs  202 . As shown a first plurality of link ends  210  extends in a first direction. The link ends  210  may be provided with a shape that is similar to the shape of link ends  40  which have been described in detail previously. At the opposite end of the module  200 , a plurality of link ends  220  are shown. The link ends  220  have a pivot opening  223  for receiving a stud  226  on the first link ends  210 . As shown toward the middle of the figure, a cover  233  extends laterally from the link end  220 . The cover  233  enables the module  200  to have fewer link pairs  202  that are spread apart farther than in the other embodiment. Adjacent modules  200  are assembled in a similar fashion as described in connection with  FIGS. 2-4  above. When the modules  200  are angled with respect to each other the shape of the link ends  210 ,  220  allows them to be intercalated and then the link end  210  with the stud  226  can be moved transversally with respect to the link end  220  having the pivot opening  223  such that the stud  226  engages with the opening  223 . After the transversal movement, rotation of the modules  200  about the pivot point brings wider edges on each link end  210 ,  220  into engagement such that lateral movement of the link ends  210 ,  220  relative to each other is prevented and the stud  226  cannot disengage from the pivot opening  223 . 
   While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.