Abstract:
A modular plastic conveyor belt that is useful in accommodating hinge rods that tend to lengthen during use and an edge module for constructing such a belt. An edge portion of the edge module has an elongated link end that provides an unimpeded growth path for a hinge rod within the confines of the belt. The edge portion of one edge module is hooked to the edge portion of an adjacent edge module by a pivot that is pivotally received in a mating receptacle on the adjacent module.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 12/779,525, “Conveyor Belt and Module Accommodating Rod Growth,” filed May 13, 2010, and incorporated entirely in this specification by reference. 
     
    
     BACKGROUND 
       [0002]    The invention relates generally to power-driven conveyors and more particularly to modular plastic conveyor belts. 
         [0003]    Modular plastic conveyor belts are constructed of a series of rows of one or more belt modules linked together end to end by hinge rods received in the interleaved hinge eyes of consecutive rows. One use for a modular plastic conveyor belt having a lot of open area for good air flow is as a cooling belt for rubber extrusions, such as tire tread and sidewall extrusions. Hinge rods made of polypropylene or acetal are commonly used in modular plastic belts and tend to wear out fairly quickly in abrasive environments, such as in a rubber-processing or tire plant&#39;s cooling line. Hinge rods made of certain nylon materials, such as nylon 6-6, have been shown to markedly increase rod life. As a consequence, nylon hinge rods are sometimes used in cooling belts. But, to hasten cooling, water is sprayed on the tire components as they are conveyed on the cooling belt. The nylon hinge rods absorb water, which causes them to grow in diameter and length. If the ends of the rods are not confined by the belt structure, the ends can grow past the outside edges of the belt and snag people or things alongside the conveyor. If the ends are confined by structure in the edges of the belt, the growing rods can push against and deform or break the edges of the belt. Sometimes the nylon hinge rods are cut short in order to accommodate the expected growth. In this case, the rods could be significantly short on wide belts, which would leave several links on the outside edge of the belt without rods. This leaves those links vulnerable to damage and reduces the effective pull strength of the belt. Thus, there is a need for a conveyor belt that can accommodate hinge-rod growth. 
       SUMMARY 
       [0004]    A conveyor belt module embodying features of the invention comprises a main portion and an edge portion. The main portion extends longitudinally from a first end to a second end of the module and laterally from a first side to a second side of the main portion. Hinge elements are spaced apart along the first and second ends of the module in the main portion. Apertures through the hinge elements are aligned along each end of the module. The edge portion extends outward from the first side of the main portion. The edge portion has an outside edge distal from the first side of the main portion. A receptacle is formed in the edge portion along one end of the module. A pivot member extends from the edge portion along the other end. The pivot member aligns longitudinally with the receptacle and has a pivot axis aligned laterally with the hinge elements along that end of the conveyor belt module. 
         [0005]    In another aspect of the invention, a conveyor belt embodying features of the invention comprises a series of rows of belt modules. Each of the rows extends longitudinally in a direction of belt travel from a first end to a second end and laterally from a first outside edge to a second outside edge. A first set of hinge elements are spaced apart along the first end of the row, and a second set are spaced apart along the second end. Laterally aligned apertures in each set of hinge elements form lateral passageways through the interleaved hinge elements of adjacent rows of modules. Hinge rods received in the lateral passageways hingedly connect the rows together. Each of the rows includes an edge module at each of the outside edges. Each edge module comprises a main portion that forms at least some of the first and second hinge elements of the row and an edge portion that extends laterally from the main portion to the outside edge. The edge portion includes a receptacle aligned with the lateral passageway along the first end of the row and a pivot member longitudinally aligned with the receptacle. The pivot member has a pivot axis laterally aligned with the lateral passageway along the second end of the row. The pivot member at the second end of the row is pivotally received in the receptacle at the first end of an adjacent row to pivotally connect the edge modules of adjacent rows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    These aspects and features of the invention, as well as its advantages, are better understood by reference to the following description, appended claims, and accompanying drawings, in which: 
           [0007]      FIG. 1  is a bottom axonometric view of two belt-edge modules embodying features of the invention; 
           [0008]      FIG. 2  is an isometric view of a portion of a conveyor belt constructed of belt-edge modules as in  FIG. 1 ; 
           [0009]      FIG. 3  is a bottom plan view of the conveyor belt of  FIG. 2 ; 
           [0010]      FIG. 4  is a top plan view of the conveyor belt of  FIG. 2 ; 
           [0011]      FIG. 5  is a top plan view of the full width of a portion of the conveyor belt of  FIG. 2 ; 
           [0012]      FIGS. 6A and 6B  are top and bottom plane views of another version of an edge module embodying features of the invention; and 
           [0013]      FIGS. 7A and 7B  are top and bottom enlarged axonometric views of the edge portions of two connected edge modules of  FIGS. 6A and 6B . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Two consecutive edge modules embodying features of the invention and suitable for use in a conveyor belt in a cooling line are shown in  FIG. 1 . Each belt module is an edge module  10  having a main portion  12  and an edge portion  14  forming an outside edge  16  of the module. The module extends longitudinally, i.e., in the direction in which a conveyor belt made of the modules would travel, from a first end  18  to an opposite second end  19  of the module. The main portion  12  extends laterally, i.e., along the width of a conveyor belt made of the modules, from a first side  20  to an opposite second side  21 . First and second sets of links  22 ,  23  extend longitudinally from opposite sides of a lateral rib  24  in the main portion  12  of the belt module. The lateral rib forms a central spine of the main portion of the module midway between the first and second ends and can also serve as a drive bar against which teeth of a drive sprocket drive a belt made of these modules. The first and second sets of links  22 ,  23  terminate in link ends that serve as hinge elements  26 ,  27  at the first and second ends  18 ,  19  of the module. The hinge elements  26  along the first end of the module are offset from the hinge elements  27  along the second end so that the first set of hinge elements  26  can be interleaved with the second set of hinge elements  27  in an adjacent module with the outside edges  16  of the modules in longitudinal alignment. Spaces  28  between laterally consecutive hinge elements on each end of the module are greater than the thicknesses of the hinge elements to allow the hinge elements to interleave. Apertures  30  through the hinge elements are aligned laterally and form a lateral passageway with the apertures in the interleaved hinge elements of an adjacent module. A hinge rod  32  received in the lateral passageway between two adjacent modules connects the modules together at a hinge joint at which the modules  10  can articulate about a drive or idle sprocket or a return roller or shoe. 
         [0015]    The edge portion  14  of the edge module  10  is attached to the first side  20  of the main portion  12 . The lateral rib  24  and a lateral stiffening bar  34 , which traverses several of the links  22  between the central rib and the first end  18  of the module, connect the edge portion to the main portion of the module. The stiffening bar, besides increasing the beam stiffness of the module near the first side, provides additional cantilever support to the edge portion  14  to prevent it from twisting about the lateral rib  24 . 
         [0016]    The edge portion  14  extends outward from the first side  20  of the main portion  12  to its distal outside edge  16 , which has an outwardly facing wall  36  that gives a belt made of these edge modules a flush edge. The edge portion is generally rectangular and has a laterally elongated link end  38  at the first end  18  of the module. The elongated link end has a concave inner surface  40 , which nestles the end  42  of the hinge rod. A thickened region  44  extending to the outside edge  16  has an interior surface  46  that is laterally aligned with the hinge rod  32  and the lateral passageway. The surface  46  is spaced from the main portion  12  by a distance great enough to allow the hinge rod to lengthen without contacting the surface and pushing outwardly against it. This distance may be as much as about one inch. 
         [0017]    In a normal belt construction, the end  42  of the headless hinge rod resides in the edge portion  14  to ensure that the rod extends through all the hinge elements. A dry rod extends slightly into the edge portion. A wet rod  32 ′ that has absorbed a lot of water extends farther into the edge portion, but not far enough to contact the surface  46  and cause the module to distort or break. Thus, the edge portion provides an unimpeded axial growth path for a hinge rod. 
         [0018]    The thickened region  44  of the edge portion also provides enough material for a receptacle  48  to be formed in the elongated link end  38  of the edge portion  14 . The receptacle has a slot  50  that opens onto the elongated link end in the bottom  51  of the edge portion. The slot communicates with an open cylindrical cavity  52  that opens onto the bottom of the edge portion and has an axis  54  aligned with the hinge axis  56  of the aligned apertures of the first set of hinge elements  26  along the first end  18  of the module. A complementarily shaped pivot member  58  extends longitudinally outward from the end portion  14  opposite the receptacle. The pivot member and the receptacle are aligned longitudinally in the edge portion of the module proximate the outside edge  16 . The pivot member  58  has a longitudinally extending arm  60  that terminates in a pivot  62 , which has a lateral pivot axis  55  aligned with the hinge axis  57  formed by the aligned apertures through the hinge elements  27  along the second end  19  of the module. The slot  50  admits the arm  60  of the pivot member of an adjacent module, and the cavity  52  receives the pivot  62  and allows it to pivot in the cavity in line with the hinge rod. The pivot connection also hooks the edge portions of adjacent modules together near the outside edge to prevent them from separating. 
         [0019]    The edge portion  14  also includes longitudinal and lateral frame sections  64 ,  65  that join with the outside edge wall  36  and the elongated link end  38  to form an outer frame. A top deck  66  with openings  68  provides a support surface on the conveying side  67  of the edge portion with plenty of open area for air to flow through the edge portion. 
         [0020]    The modules may be made of thermoplastic materials, such as polyethylene, polypropylene, acetal, or composite polymers in an injection-molding process. The hinge rod is made of a durable, abrasion-resistant material, such as nylon 6-6, which also tends to absorb water and to lengthen. 
         [0021]    The edge modules  10  shown in  FIG. 1  are joined side by side with other edge modules and interior modules  11  which do not include edge portions, to form a belt row  70 , as shown in  FIG. 5 . Consecutive rows of belt modules are joined end to end at hinge joints  72  by hinge rods  32  received in the interleaved hinge elements of adjacent rows to form an endless conveyor belt  74 . 
         [0022]    As shown in  FIGS. 2-4 , which depict one side of the belt, the belt  74  is wrapped around a set of drive sprockets  76  having bores  78  for mounting on a shaft rotated by a motor (not shown). Sprocket teeth  80  on the periphery of the drive sprocket extend into gaps  82  between the lateral rib  24 , or drive bar, and the hinge elements of an adjacent module and push against the drive bar to move the belt in a direction of belt travel  84  as the sprockets rotate. The endless belt loop is trained between drive sprockets  76  and similar idle sprockets (not shown). 
         [0023]    Another version of an edge module that can be connected together with other modules and hinge rods to construct a conveyor belt as in  FIGS. 2-4  is shown in  FIGS. 6A and 6B . The edge module  90  comprises a main portion  92 , which is shown as identical to the main portion  12  of the edge module  10  of  FIG. 1 , and an edge portion  94 , which differs from the edge portion  14  of the edge module of  FIG. 1 . In the edge portion  94 , a horseshoe-shaped receptacle  96  is positioned generally midway along a laterally elongated link end  98 , but it could be closer or farther from the outside edge  99  of the module. The receptacle  96  separates the link end  98  into two segments that extend laterally from opposite side walls  100 ,  101  of the receptacle. The rounded closed end  102  of the horseshoe-shaped receptacle  96  is formed with a strengthening rib  104  that extends laterally across the edge portion  94 . Ears  106 ,  107  at the open end of the receptacle extend toward each other from opposite side walls  100 ,  101 . The confronting faces of the ears are separated by a slot  108  opening into the receptacle. A pivot member  110  extends longitudinally outward from the opposite end of the edge portion  94 . Like the pivot member  58  of the edge module  10  in  FIG. 1 , the pivot member  110  has a longitudinally extending arm  112  that terminates in a pivot  114 . Opposing sides  116 ,  117  of the pivot  114  are angled to converge with distance from the arm  112 . Thus, the pivot is thicker at its junction with the arm. The pivot member&#39;s arm  112  is aligned laterally with the slot  108  at the open end of the receptacle  96 . Although the edge module  90  is shown with one pivot member and one receptacle, the module could have two or more of each spaced along the width of the edge portion. 
         [0024]    As shown in  FIGS. 7A and 7B , the pivot  114  is received in the receptacle  96  of an adjacent edge module with the arm  112  residing in the slot  108 . Hooks  118 ,  119  at the ends of the ears  106 ,  107  retain the pivot in place in the receptacle. Although the hook  119  on the outer side wall  101  is shown on the top side of the module and the hook  118  on the inner side wall  100  is shown on the bottom side, both could be formed on either the top side or the bottom side. The hinge axis  120  through the lateral passageway formed by the aligned apertures  30  in the interleaved hinge elements  26 ,  27  in the main portions  92  of the joined, adjacent modules is aligned with the pivot axis  121  of the pivot  114 . Unlike the pivot  62  in the module  10  of  FIG. 1 , the pivot  114  has an aperture  122  coaxial with the hinge axis  120  and the pivot axis  121 . Apertures  124  through the side walls  100 ,  101  of the receptacle  96  are also aligned with the hinge and pivot axes at the hinge joint. The apertures in the pivot and the side walls of the receptacle facilitate entry of the hinge rod  32  through the edge portion  94  and into the lateral passageway. The converging sides  116 ,  117  of the pivot also aid in guiding the hinge rod into the apertures without catching. And, as shown in  FIG. 7B , even though the hinge rod need extend from the main portion only slightly into the edge portion  94 , the apertures in the pivot and the side walls of the receptacle accommodate growth of a wet rod  32 ′ out to a position closer to the outside edge  99  of the module  90 . A concave inner surface  126  on the segmented elongated link end  98  nestles the end of the hinge rod that extends into the edge portion  94  of the module  90 . 
         [0025]    The details of the specific examples are used to help describe the invention. The scope of the invention is defined by the following claims.