Abstract:
This disclosure provides a guard assembly and its individual guards for protecting a conveyor system, such as the center conveyor frame. Related methods of installing or removing the individual guards and the guard assembly are also provided.

Description:
TECHNICAL FIELD  
       [0001]    This disclosure relates, generally, to a guard assembly for protecting parts of a conveyor system from the bulk material being transferred by the conveyor system, and more particularly, to a guard assembly having a plurality of individual guards. 
       BACKGROUND  
       [0002]    A machine may include a conveyor system for receiving material from a source in a hopper and then transferring the material to a predetermined destination. For example, when building roadways, paving machines may be used to deposit significant amounts of paving material. A conveyor system on a paver transfers the paving material from the paver hopper for discharge onto the roadbed. A typical paving material includes asphalt or asphalt concrete. 
         [0003]    An asphalt paver at the construction site is generally a state-of-the-art self-propelled construction machine designed to receive, convey, distribute, profile and partially compact the asphalt material. The paver accepts the asphalt material into a receiving hopper at the front of the machine, conveys the material from the hopper to the rear of the machine with parallel slat conveyors, distributes the asphalt material along the width of an intended ribbon or mat by means of two opposing screw or spreading conveyors, and profiles and compacts the asphalt material into a mat with a free-floating screed. 
         [0004]    Each slat conveyor that moves the asphalt material from the receiving hopper to the rear of the paving machine generally consists of two parallel slat chains with a multitude of transverse slats connected therebetween. Each slat chain is pulled by one of two sprockets mounted on a common shaft which, in turn, is driven by appropriate power transmission chains, gear boxes or the like. 
         [0005]    Asphalt itself is usually a black and highly viscous liquid or semi-solid. It is present in most crude petroleums and in some natural deposits. When used in road construction, asphalt usually functions as a binder for a gravel or rock base. The raw material mixture is referred to as a “bituminous aggregate,” and the finished road surfacing material is usually called “asphalt concrete.” The bituminous aggregate is typically stored and transported at temperatures around 150° C. to prevent hardening. Thus, the asphalt material conveyor system needs to withstand the high-temperature and rough gravel or rock particles bound within the aggregate the mix is being dumped into the hopper, and more particularly, as the abrasive mix moves through the conveyor system. It is also desirable to have a conveyor system with features that facilitate the transfer of the molten aggregate material from the hopper to the roadbed to minimize the amount of leftover asphalt material (which forms cold asphalt build-up) in the conveyor system. 
         [0006]    U.S. Pat. No. 3,453,939 describes two conveyors on a paver that are separated by a horizontal wall and paving material is confined thereon by shield plates inclined downwardly from the side walls and a divider wall between the two conveyors. The shield plates appear to protect the side walls and the divider walls from the paving material. But it is not clear whether or how these shield plates can be readily or individually removed when repair or replacement is needed. 
         [0007]    For other conveyor systems, it may also be desirable to include a shield or guard system to protect certain parts of the conveyor systems from the bulk material they are designed to transfer. 
         [0008]    The present disclosure is directed to addressing one or more needs discussed above. 
       SUMMARY OF THE INVENTION  
       [0009]    A first aspect of the present disclosure provides a guard for protecting a conveyor frame or walls of a hopper wall and diverting material toward a conveyor system. The guard includes a first support member and a diverter member. The diverter member may have an end attached to the first support member and defining a material diverter surface thereon. The material diverter surface is positioned to direct material away from the conveyor frame or the hopper wall and towards the conveyor system. The diverter member defines an access portion therein and is configured to enclose a fastener assembly therein. 
         [0010]    Another aspect of the present disclosure provides a guard assembly for protecting a conveyor frame or a hopper wall. The guard assembly includes at least two individual guards. Each of the individual guard includes a first support member and a diverter member. The diverter member may have an end attached to the first support member and defining a material diverter surface thereon. The material diverter surface is positioned to direct material away from the conveyor frame or the hopper wall and towards the conveyor system. The diverter member defines an access portion therein and is configured to enclose a fastener assembly therein. The at least two individual guards may be situated opposite to each other and attached to either side of the conveyor frame. 
         [0011]    A further aspect of the present disclosure is directed to a conveyor system for receiving bulk material therein and directing the bulk material to a selected destination. The conveyor system includes first and second hopper walls and a moveable conveyor belt positioned thereunder. The conveyor system further includes a conveyor frame to support the moveable conveyor belt. The conveyor system also includes at least one removeable guard defining a material diverter surface, the material diverter surface being positioned to direct the bulk material away from the conveyor frame or the first and second hopper walls and towards the moveable conveyor belt. The at least one guard may be removeably attached to the conveyor frame or the first and second hopper walls through a fastener assembly at least partially recessed relative to the material diverter surface. 
         [0012]    An additional aspect of the present disclosure provides a method for installing a guard for protecting a conveyor frame or a hopper wall and diverting material toward a conveyor system. The guard includes a first support member and a diverter member. The diverter member may have an end attached to the first support member and defining a material diverter surface thereon. The material diverter surface is positioned to direct material away from the conveyor frame or the hopper wall and towards the conveyor system. The diverter member defines an access portion therein and is configured to enclose a fastener assembly therein. The method includes attaching the guard to the conveyor frame or the hopper wall by securing the fastener assembly to the conveyor frame or the hopper wall through the access portion. The first support member of the guard may further include one or more dowels, and the method accordingly includes aligning the one of more dowels to one or more openings on the conveyor frame or the hopper wall configured to receiving the one or more dowels. 
         [0013]    A further aspect of the present disclosure provides a method for removing a guard from a conveyor frame or a hopper wall. The guard includes a first support member and a diverter member. The diverter member may have an end attached to the first support member and defining a material diverter surface thereon. The material diverter surface is positioned to direct material away from the conveyor frame or the hopper wall and towards the conveyor system. The diverter member defines an access portion therein and is configured to enclose a fastener assembly therein. The method includes removing the guard from the conveyor frame or the hopper wall by unfastening the fastener assembly that secures the guard to the conveyor frame or the hopper wall through the access portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]      FIG. 1  is a diagrammatic illustration of a paving machine according to an exemplary disclosed embodiment. 
           [0015]      FIG. 2  is a diagrammatic view of a conveyor system of the paving machine shown in  FIG. 1 , including a guard assembly of four individual guards to protect the center conveyor frame and a guard assembly on either side of the hopper walls. 
           [0016]      FIG. 3  is a perspective view of an individual guard of the conveyor system shown in  FIG. 2 , including a wear strip. 
           [0017]      FIG. 4  is a perspective view of the individual guard of the conveyor system shown in  FIG. 2 , positioned to display the attachment means. 
           [0018]      FIG. 5  is a cross-sectional view of the center guard assembly shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION  
       [0019]    Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same or corresponding reference numbers will be used throughout the drawings to refer to the same or corresponding parts. 
         [0020]      FIG. 1  is an illustration of a paving machine  10 . Although paving machine  10  is depicted in the figures as an asphalt paver, the presently disclosed guard and guard assembly may be used on any kind of conveyor system for transferring bulk material. Exemplary bulk material to be transferred by the disclosed conveyor system may include asphalt, concrete, or loose aggregate materials such as crushed gravel. 
         [0021]    Paving machine  10  may include a tractor  12  having a power source  14 , one or more traction devices  16 , and a hopper  18  for containing paving material. Paving machine  10  may also include a screed  20  attached to tractor  12  by tow arms and towed behind tractor  12  to spread and compact paving material into a mat  24  on a paving surface  26 . 
         [0022]    Paving material may be dumped into hopper  18  from trucks that deliver the paving material to a work site. Paving machine  10  may include one or more conveyors  22  at the bottom of hopper  18 . Conveyors  22  may be positioned side-by-side, shown as conveyors  103  and  105  in  FIG. 2 , and run parallel to one another back to the rear of tractor  12 . Conveyors  22  may transport paving material from hopper  18  to the rear of tractor  12  where it may be dropped behind tractor  12  in front of screed  20  onto paving surface  26  into a pile  28  (shown in a cut away portion  30  of  FIG. 1 ). As paving machine  10  travels forward, pile  30  may be evenly spread and compacted by screed  20 . 
         [0023]    The speed of conveyors  54  may be variable to make pile  28  higher or lower. The pile height may be increased or decreased by varying the conveyor speed relative to the speed at which paving machine  10  is traveling. For example, if the conveyor speed is high, relative to the paving machine speed, then paving material may accumulate behind tractor  12  in front of screed  20 , thus resulting in a higher pile. If the conveyor speed is low, relative to the paving machine speed, then the paving material may be spread over a longer stretch of paving surface  26 , resulting in a lower pile. 
         [0024]    The speed of each conveyor may be independently variable. Independently varying the speed of conveyors  22  may enable an increase or decrease in the pile height toward one side of paving machine  10  or the other. This feature may be used to even out an inadvertently lopsided pile or to purposely create a lopsided pile. 
         [0025]      FIG. 2  depicts a conveyor system  100  according to one disclosed embodiment. The conveyor system  100  includes a center conveyor frame  102 , a first hopper wall  104  and a second hopper wall  106 . The conveyor system  100  also includes conveyors  103  and  105 . A guard assembly  101  of individual guards  108 ,  110 ,  112 , and  114  protects the conveyor frame  102  and diverts material toward the conveyors  103  and  105 . 
         [0026]    As illustrated, the guards  108  and  110  are assembled sequentially along and attached to one side of the center conveyor frame  102 , whereas the guards  112  and  114  are assembled sequentially along and attached to the opposite side of the center conveyor frame  102 . The length of the assembly  101  is sufficient to cover substantially the entire length of the frame  102 . Alternatively, the assembly  101  may be shorter and covers only a portion of the frame  102 , such as for example, the portion corresponding to the part of the conveyors  103  and  105  receiving material from a dump truck. 
         [0027]    A wear strip  122  is positioned at the peak intersection of the guards  108   112 ,  110  and  114 , for the purpose of diverting material away from the centerline of the guard assembly  101  and to protect the center conveyor frame  102 . The wear strip  122  can be sufficiently long to cover the entire length of the frame  102 . Or, the length of the wear strip  122  can be shortened to cover only a portion of the center conveyor frame  102 . The wear strip  122  may be formed of a number of different materials, such as a metal material, a polymer material, or any other material suitable for the bulk material that the conveyor system  100  is designed to receive and transfer. 
         [0028]    In addition, the individual guards  109  and  111  are assembled sequentially along and attached to a side of the first hopper wall  104  facing the conveyor  103 . The individual guards  113  and  115  are also assembled sequentially along and attached to a side of the second hopper wall  106  facing the conveyor  105 . 
         [0029]    Referring now to  FIG. 3 , which provides an amplified view of the individual guard  108  associated with the wear material  122 . The guard  108  includes a first support member  124  and a second support member  128 . These two support members  124  and  128  may be formed from channel material or may include two separate plates attached to each other along one side by welding or other means. In the illustrated embodiment, the second support member  128  is in the form of a plate. In alternative embodiments, the second support member may include a gusset. 
         [0030]    The guard  108  also includes a diverter member  126 , which defines a diverter surface set at an angle  132  relative to the first and second support members  124  and  128 . The angle  132  may be set at a value greater than the angle of repose for the bulk material being transferred by the conveyor system  100  to facilitate such material transfer and reduce the amount of the material being left behind. The angle of repose is usually defined as the angle with a horizontal surface formed when free-flowing material comes to rest, and the material within the angle of repose can be a flow barrier. 
         [0031]    The diverter member  126  of the guard  108  also includes first and second apertures  116  and  118 , which are horizontally aligned with first and second fastening points  130  and  132  on the first support member  124  (as shown in  FIG. 4 ). The fastening points  130  and  132  are each configured to receive a fastener assembly (not shown) to removeably attach the guard  108  to the center conveyor frame  102 . Accordingly, the apertures  116  and  118  provide a window of exposure so that a fastener head can each be engaged through the apertures  116  and  118  by a tool as is customary. This allows the attachment or removal of the guard  108  to the center conveyor frame  102  through a removeable fastener assembly in a recessed position relative to the diverter surface. This recessed positioning reduces the exposure of the hardware relative to the abrasive aggregate as it is transferred by the conveyor system. As a result, the conveyors system can be quickly maintained or serviced without destroying the guards or fastening means. 
         [0032]    The guard  110  shown in  FIG. 2  also includes a diverter member aligned with the diverter member  126  of the guard  108  to form a substantially continuous material diverting surface. An access aperture  120  is included to provide a window of exposure so that a fastener head can be engaged through the aperture  120  by a tool as is customary, thereby allowing the attachment or removal of the guard  110  to the frame  102  through a removeable fastener assembly in a recessed position relative to the diverter surface. In the illustrated embodiment, the guard  110  includes one access aperture  120 , whereas the guard  108  includes two access apertures  116  and  118 . For the guard  110 , additional access is available from the back of the machine including the conveyor system  100 . 
         [0033]    As shown in  FIG. 4 , the first support member  124  also includes first and second attachment points  134  and  136 , which may each include a hole. A pair of dowels  138  and  140  press fit into the holes at the attachment points  134  and  136  to provide rigid support. This feature is further illustrated in  FIG. 5 , a cross-sectional view of the guard assembly  101 . Accordingly, during installation of the guard  108  to the center conveyor frame  102 , each of the dowels  138  and  140  aligns with and extends into corresponding holes  142  and  144  on the frame  102 . The dowels  138  and  140  then provide additional vertical support for the guard  108  when the conveyor system  100  is receiving bulk material for transfer. The dowel design also facilitates the guard to be piloted onto the dowels for each assembly, and regarding removal of the guard from the frame, there is no fastener to remove rather the dowels pull out directly from the holes in the frame. 
         [0034]    In certain embodiments, the guard  112  can be attached to the frame  102  with the same removeable fastener assemblies (through the access apertures  116  and  118 ) and dowels  138  and  140  that attach the guard  108  to the frame  102 . In these embodiments, the guard  112  may include a diverter member that does not have any access apertures. This reduces the number of access apertures of the guard assembly. 
         [0035]    Similarly, the guard  114  can be attached to the frame  102  with the same removeable fastener assembly (through the access aperture  120 ) and dowels that attach the guard  110  to the frame  102 . In these embodiments, the guard  114  may include a diverter member that does not have any access apertures. This further reduces the number of access apertures of the guard assembly. 
         [0036]    Alternatively, the guard  112  may be a mirror image of the guard  108 . The guard  112  may include a diverter member that defines its own access apertures. Fastener assemblies different than those used for attaching the guard  108  to the frame  102  may be employed to attach the guard  112  to the frame  102 . This may allow completely separate attachment or removal of the guards  108  and  112 . Similarly, the guard  114  may be a mirror image of the guard  110  and use a different fastener assembly, thereby allowing separate attachment or removal of these two guards. 
       INDUSTRIAL APPLICABILITY  
       [0037]    Referring to  FIG. 2 , the guard assembly  101  of four individual guards  108 ,  110 ,  112 , and  114  is used to protect, and divert material to the conveyors  103  and  105  away from, the center conveyor frame  102 . In addition, an assembly of two guards ( 109  and  111 , or  113  and  115 ) is used to protect, and divert material to the conveyor  103  or  105  from the first hopper wall  104  or the second hopper wall  106 ; these two-guard assemblies can be attached or removed to their respective hopper walls by accessing from outside of the machine including the conveyor system  100 . 
         [0038]    Although the illustrated embodiments are directed to an asphalt paver, the disclosed guard and guard assembly can be adapted to any conveyor system transferring bulk material that may cause wear of certain parts of the conveyor system. The disclosed guard and guard assembly facilitate material transfer by including a diverter member defining a material diverter surface. The material diverter surface is set an angle relative to the conveyor surface, which angle can be configured to be greater than the angle of repose of the material being transferred to facilitate material flow through the conveyor system, reduce the amount of leftover material, and reduce the need to remove build-up leftover material in the conveyor system. 
         [0039]    Further, the hardware responsible for attaching and supporting the guard and guard assembly to the conveyor system (e.g., the fastening assembly utilizing the fastening points  130  and  132 , and the dowels  138 ,  140  and their corresponding attachment points  134  and  136 ) is at a position recessed relative to the material being transferring, thus reducing wear or other damage of the hardware by the material. The use of an assembly of individual guards also allows for individual replacement or repair, which may reduce cost and machine downtime. 
         [0040]    For the illustrated asphalt paver, the disclosed guard and guard assembly substantially eliminate hardware (e.g., hardware used to attach the guards to the conveyor system) exposed to asphalt, which decreases the time necessary for cleaning up around the hardware before it can be removed so as to detach the guards from the paving machine. The recessed location of the hardware also reduces its exposure to asphalt, which reduces its wear or damage. The use of dowels in addition to the fastening assemblies also facilitates the installation and removal of the guards. 
         [0041]    Further, the guard assembly (including the guards  108 ,  110 ,  112 , and  114 ) for the center conveyor frame  102  includes a wear material  122 , which provides further protection for the frame  102 . 
         [0042]    It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed paving machine output monitoring system without departing from the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the invention being indicated by the following claims and their equivalents.