Patent Publication Number: US-2015083503-A1

Title: Weighing Module

Description:
BACKGROUND OF THE INVENTION 
     THIS invention relates to a weighing module. More specifically, the invention relates to a weighing module, which individually or together with other weighing modules, acts as a single idler weighing apparatus for a conveyor belt assembly. 
     Many types of single idler weighing apparatus are known. Most however, are not accurate in that the weight recording is influenced by dynamic forces associated with conveyor movement. 
     It is therefore an object of the invention to provide a more accurate single idler weighing apparatus that minimises the effects of dynamic forces associated with conveyor movement, both simply and cost effectively. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a weighing module for weighing a load applied to an object, the weighing module including:
         at least one first mounting and at least one second mounting being attachable to a primary part of the object such that the first and the second mountings are spaced apart from one another;   at least one third mounting and at least one fourth mounting being attachable to a secondary part of the object such that the third and the fourth mountings are spaced apart from one another;   at least a first bar member having a first end for pivotally mounting to the first mounting and an opposing second end for pivotally mounting to the third mounting;   at least a second bar member having a first end for pivotally mounting to the second mounting and an opposing second end for pivotally mounting to the fourth mounting, each end of the bar members being pivotally mounted on the mounting by a mounting pin passing through correspondingly aligned mounting apertures defined in the respective end of the bar members and the respective mounting so as to retain the first bar and the second bar in a spaced apart and parallel orientation relative to one another; and   one or more load cells attachable between the one or more mountings attachable to the primary part of the object and the one or more mountings attachable to the secondary part of the object   such that in use and under load, the bar members and mountings co-operate with one another to substantially nullify any force component acting in a plane coplanar or substantially parallel to a plane in which the bar members lie, thereby to enable the load cell to measure substantially only a strain caused by the weight of the load on the object.       

     In a first preferred embodiment, each of the mountings is a fork-like mounting formation for receiving the respective end of the respective bar member, the mounting pin pivotally capturing the end of the bar member within the fork-like mounting formation. 
     In an alternative embodiment, each of the mountings comprise a male mounting formation and each of the ends of the bar members are fork-like formations for receiving the male mounting formation therein, the mounting pin pivotally capturing the male mounting formation of the mounting within the fork-like mounting formation of the bar members. 
     The first and second mountings are typically opposing ends of a common primary mounting member, the common primary mounting member being attachable to the primary part of the object. Furthermore, the third and the fourth mountings are generally opposing ends of a common secondary mounting member, the common secondary mounting member being attachable to the secondary part of the object. Preferably, the mounting pins ride on bearings mounted in the mountings, in the ends of the bar members or in both. 
     The common primary mounting member may be mounted to a primary mounting body and the common secondary mounting member may be mounted to a secondary mounting body, the primary and the secondary mounting bodies being attachable to the primary and secondary parts of the object respectively. 
     Generally, the primary and the secondary mounting bodies are primary and secondary housings for housing the common primary and secondary mounting members respectively, the primary and the secondary housings being spaced apart from one another by the bar members extending there between, so as to define a gap between the primary and the secondary housings. 
     Typically, the one or more load cells are connected between the primary and secondary housings across the gap defined there between. 
     Preferably, the each of the primary and the secondary housings include a base member and a cover member, the base member comprising a base with sidewalls extending outwardly there from, the cover member being engagable with the sidewalls to define, between the base, the sidewalls and the cover member, an inner cavity for housing the common mounting members and respective ends of the bar members mounted thereto. 
     In a preferred application of the invention, the object is a conveyor belt assembly, the primary part of the object being an idler assembly and the secondary part of the object being a runner structure running between the multiple idler assemblies on the conveyor belt assembly. Preferably, the primary housing is attachable to the primary part of the object and the secondary housing is attachable to the secondary part of the object, the primary and the secondary housings being attachable to the object by fasteners. More preferably, the fasteners are nuts and bolts. 
     In accordance with a second aspect of the invention, there is provided a weighing apparatus including a pair of weighing modules in accordance with the preceding description thereof, the secondary housings of the weighing modules being connected to each other on opposing ends of a cross member, such that the primary housings of each of the weighing modules are attachable to opposing ends of the idler assembly and the secondary housings of each of the weighing modules are attachable to opposing sides of the runner structure of the conveyor belt assembly. 
     In accordance with a third aspect of the invention, there is provided an idler assembly for weighing a load passing there over including:
         a support bracket for supporting one or more idler mounting sub-brackets on which idlers are supportable;   a pair of weighing modules in accordance with any one of claims  11  to  13 , the primary housings of each of the weighing modules being attached to opposing ends of the support bracket; and   a cross member attached at each opposing end to the secondary housings of the weighing apparatus, the secondary housings being attachable to opposing sides of a runner structure of a conveyor belt assembly.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a weighing module in accordance with the present invention; 
         FIG. 2  is a front view of the weighing module of  FIG. 1 ; 
         FIG. 3  is a rear view of the weighing module of  FIG. 1 ; 
         FIG. 4  is a side view of the weighing module of  FIG. 1 ; 
         FIG. 5  is a top view of the weighing module of  FIG. 1 ; 
         FIG. 6  is a bottom view of the weighing module of  FIG. 1 ; and 
         FIG. 7  is a perspective view of the weighing apparatus made up of a pair of weighing modules fitted on an idler assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     A weighing module according to a preferred embodiment of the invention is designated generally with reference numeral  10  in  FIG. 1 . The weighing module  10  comprises mountings  12 , 14 , first and second bar members  16 , 18  extending between the mountings  12 , 14  and a load cell  20 . Although the mountings  12 , 14  have been illustrated in the accompanying figures as common primary and secondary mounting members  12 , 14 , each of the mountings may be separate and individual mountings. 
     The common primary mounting member  12  comprises fork-like mounting formations  12 A, 12 B. Similarly, the common secondary mounting member  14  comprises fork-like mounting formations  14 A, 14 B. The fork-like mounting formations  12 A, 12 B, 14 A, 14 B are sized and shaped to receive respective ends of the bar members  16 , 18 . The respective ends of the bar members  16 , 18  are pivotally captured in the respective fork-like mounting formations  12 A, 12 B, 14 A, 14 B in mounting pins (not shown) passing through correspondingly aligned mounting apertures  22  defined in the common primary and secondary mounting members  12 , 14  and the bar members  16 , 18 . In this configuration, the bar members  16 , 18  are retained in a spaced apart, parallel orientation with respect to each other. 
     Although the common primary and secondary mounting members  12 , 14  have been illustrated with fork-like mounting formations  12 A, 12 B, 14 A, 14 B, it will be appreciated that in an alternative embodiment, the common primary and secondary mounting members  12 , 14  could comprise male mounting formations pivotally captured within fork-like formations on the opposing ends of the bar members  16 , 18 . In either embodiment, it is preferable for the mounting pins to ride on bearings (not shown) mounted in the common primary and secondary mounting members  12 , 14  and/or the bar members  16 , 18   
     The common primary mounting member  12  is mounted on a primary mounting body in the form of a primary housing  24  having a base  26 , sidewalls  28  and a cover member (not shown), the cover member being engagable with the sidewalls  28  to define, between the base  26 , the sidewalls  28  and the cover member, an inner cavity for housing at least the common primary mounting member  12  and the respective ends of the bar members  16 ,  18 . 
     The common secondary mounting member  14  is mounted on a primary mounting body in the form of a secondary housing  30  having a base  32 , sidewalls  34  and a cover member (not shown), the cover member being engagable with the sidewalls  34  to define, between the base  32 , the sidewalls  34  and the cover member, an inner cavity for housing at least the common secondary mounting member  14  and the respective ends of the bar members  16 ,  18 . The bar members  16 , 18  space the primary and the secondary housings  24 , 30  from one another so as to define a gap  36  between there between, across which the load cell  20  is operative. 
     It will be appreciated that the weighing module  10  may be retrofitted directly to an object for the purposes of weighing the load applied to the object. Alternatively, a pair of weighing modules  10  may be fixed to one another to form a weighing apparatus  200  for weighing the load passing over a single idler assembly  300  on a conveyor belt assembly. 
     With reference now also to  FIGS. 2 to 7 , the weighing apparatus  200  is made up of a pair of weighing modules  10  fixed to one another across a cross member  38 , fastened to cross member brackets  40  extending outwardly from the secondary housing  30  of each of the weighing modules  10 . To further support the weighing modules  10 , brace members  42  are secured between a brace support bracket  44  extending outwardly from the primary housing  30  of each of the weighing modules  10  and the cross member  38 . 
     Extending outwardly from each of the primary housings  24  are idler assembly support brackets  46  onto which an idler assembly  300  is supportable. It will be appreciated that the weighing apparatus  200  may be retrofitted to an existing idler assembly on a conveyor belt assembly or purpose built onto an idler assembly, mountable to runners  400  of the conveyor belt assembly on mounting brackets  48  extending outwardly from the secondary housings  30  of each of the weighing modules  10 . 
     In use, the bar members  16 , 18  and mountings  12 , 14  co-operate with one another to substantially nullify any force component acting in a plane coplanar or substantially parallel to a plane in which the bar members  16 , 18  lie, thereby to enable the load cell  20  to measure substantially only a strain caused by the weight of a load on the idler assembly  300  (or other object). 
     Although the invention has been described above with reference to preferred embodiments, it will be appreciated that many modifications or variations of the invention are possible without departing from the spirit or scope of the invention. 
     For example, it will be appreciated that the mounting pins could be affixed directly to primary and secondary housings  24 , 30 , with the bar members  16 , 18  pivotally mounted thereon. However, the direct mounting of the mounting pins  22  to the primary and secondary housings  24 , 30  is a contributing factor to the possible inaccuracy of the weighing module  10 . 
     As a result, it has been found that the accuracy of the weighing module  10  can be increased by pivotally mounting the bar members  16 , 18  on mounting pins passing through correspondingly aligned mounting apertures  22  in the bar members  16 , 18  and precision manufactured common mounting members  12 , 14  being fixed to the primary and secondary housings  24 , 30 . Under this new method of manufacturing the weighing module  10 , the mounting pins float in a spaced apart relationship relative to the primary and secondary housings  24 , 30 . It will be appreciated further that the bearings on which the mounting pins ride, further increase the accuracy of the weighing module  10 .