Abstract:
A guard adapted for enclosing an exposed return roller in a conveyor belt system. The guard attachment brackets are adapted to utilize the existing attachment point hardware of the exposed return roller to facilitate guard installation on an existing conveyor system. The attachment brackets provide adjustment of the guard relative the return roller. The guard permits visual inspection to detect accumulation of debris between the guard and return roller. The guard may also be adapted with wiper extensions for cleaning debris from the conveyor belt surface.

Description:
FIELD OF THE INVENTION 
     The present invention is within the general field of conveyor belt transport systems. More specifically, to conveyor belt systems having an exposed return roller extending below the supporting conveyor frame. Most narrowly, the present invention relates to a guard for protecting workers from the hazards associated with exposed return rollers in a mining material production or distribution facility. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to conveyor belt systems used in a mining material production or distribution facility. More specifically, the present invention relates to overhead conveyor belt systems where, by elevation of the conveyor belt systems from the manufacturing or distribution facility floor, valuable floor space is reclaimed. While elevation of the conveyor belt system reclaims valuable floor space for the positioning of additional processing stations or movement of items between different locations in a facility, these elevated conveyor belt systems present operational hazards to workers on the facility floor. 
     Overhead conveyor belt systems are supported by a large frame member, with return roller assemblies supporting the conveyor belts along their return paths. These return rollers are often exposed and extend well below the support frame structures, posing various hazards to workers. The rollers create a pinch point hazard. These extended rollers pose a significant strike hazard to workers walking under the system. These rollers may also fall from the frame members and injure a worker. Additionally, the rollers may fall into other processing machinery causing machinery damage or manufacturing delays. Finally, the exposed rollers may pose a significant pinching hazard, wherein the rollers may draw loose materials or a worker&#39;s limbs between the roller and the belt. These hazards are more pronounced where the rollers extend in close proximity to a work station area where a worker&#39;s attention will be focused on performing a particular mining, manufacturing or distribution task. 
     In operations where the conveyors move significant amounts of loose material, the loose materials may adhere to the belts and accumulate in critical locations along the belt track, subjecting the system to additional wear and tear, and premature equipment failures. 
     Conventional roller guards can protect against many of these hazards. However, these guards often do not permit inspecting the return rollers while the conveyor system is in operation. Thus, the accumulation of debris in the rollers may not be detected until predetermined inspection intervals, which may not be scheduled until after significant damage to the rollers or belt has already been sustained. 
     Therefore, there is a need for a device that protects workers from the hazards of exposed rollers during operation of the conveyor belt system. The device should also prevent the accumulation of debris in the belt system while providing ready inspection means for detecting the accumulation of damaging debris therein. Similarly, the device should be easily removed to assist maintenance personnel with the removal of accumulated debris. 
     Similarly, since the guards are intended to improve the safety and reliability of existing conveyor systems, they should be readily adapted to fit a wide range of existing conveyor systems and configurations. 
     SUMMARY OF THE INVENTION 
     The present invention provides a return roller guard satisfying all the needs described above. Accordingly, the exposed roller guard of the present invention prevents striking the conveyor system exposed roller by means of a rigid guard member substantially enclosing the exposed roller. This aspect of the guard also serves to contain a roller that has either partially or completely separated from the conveyor system. Additionally, by enclosing the exposed roller, the guard substantially reduces the pinch hazard by preventing the roller from guiding objects towards the pinch point at the junction between the roller and the belt. 
     According to the present invention, the rigid guard member is provided with a plurality of holes extending through the guard member. These holes permit visual inspection of the area between the roller and the guard member with the conveyor system operating. Moreover, small debris is permitted to fall through these holes thereby preventing their accumulation within the guard. 
     The roller guard of the present invention may further include a pair of wipers, the wipers cleaning debris from the belt surface before and after encountering the return roller. The wipers further reducing exposure to the pinch hazard of the roller by deflecting obstructions away from the translating conveyor belt. 
     The guard attachment means of the present invention permit adjustment of the guard relative the roller and further permits adjustment of the wipers against the belt surface. Moreover, the brackets of the present invention permit the guard to be readily hung from industry standard roller attachment brackets permitting easy installation of the guard on existing conveyor systems and facilitating maintenance of the rollers during scheduled and unscheduled maintenance procedures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Apparatus embodying features of my invention are depicted in the accompanying drawings, which form a portion of this disclosure wherein: 
     FIG. 1 is a side elevation view of a typical conveyor belt system with the guard of the present invention covering the return rollers; 
     FIG. 2 is a perspective view of a return roller assembly enclosed by the guard of the present invention; 
     FIG. 3 is a sectional view of a return roller and the guard of the present invention; 
     FIG. 4 is a side elevation view of a return roller and the guard of the present invention; and 
     FIG. 5 is an end view of a return roller and the guard of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings for a clearer understanding of the invention, it may be seen that FIG. 1 shows a typical return roller  11  supporting a conveyor belt  12  of a standard conveyor belt system  10 . Return roller  11 , having a shaft  15 , is attached to a frame member  14  of conveyor belt system  10  by attachment means, such as bolts or pins  16  received through return idler brackets  13 . Guard member  21  of the present invention is shown enclosing return roller  11 . 
     As is best seen in FIGS. 2 and 3, in the present embodiment, guard member  21  is formed from expanded metal. However, it will be recognized that guard member  21  can be formed out of many other materials while still providing the benefits disclosed herein. Guard member  21  is substantially U-shaped, defining guard member first  22  and second  23  legs and a guard member arc  24  integrally connecting guard member first  22  and second  23  legs. Guard member arc  24  has a predetermined width corresponding to the diameter of return roller  11 , such that a desired lateral clearance  27  is provided between roller  11  and guard member first  22  and second  23  legs. Similarly, guard member first  22  and second  23  legs have a predetermined length corresponding to the diameter of return roller  11 , such that a desired vertical clearance  28  is provided between roller  11  and guard member arc  24 . Guard member  21  has a predetermined longitudinal length corresponding to the longitudinal length of return roller  11 . 
     End bands  29  are attached by a spot weld, or similar means, to opposite ends of guard member  21 . End bands  29  are substantially U-shaped corresponding to the U-shape of guard member  21 . End bands  29  provide guard member  21  additional structural support and a smooth finished edge. 
     First  31  and second  32  support bars are attached by spot weld, or other attachment means, along the longitudinal length of guard member first  22  and second  23  legs respectively. First  31  and second  32  support bars provide attachment points  33  at each end thereof for attachment of guard member  21  and support bars  31  and  32  to end brackets  41 . 
     End brackets  41  are formed in a bridge-shape, having a central upper length  42  and guard accepting extensions  43  projecting downwardly and normal the ends of upper length  42 . Guard accepting extensions  43  are separated by a distance corresponding to the width between first  31  and second  32  support bars. Guard accepting extensions  43  having a slot  44  for accepting attachment means, such as a bolt or pin  47 , through each support bar attachment point  33  for securing guard member  21  to guard accepting extensions  43 . Slot  44  further provides vertical adjustment of guard member  21  relative to return roller  11 . Upper length  42  has slots  46  for attachment to distal ends  62  of guard mounting brackets  61 . Guard mounting bracket distal ends  62  have a plurality of holes substantially aligned with slots  46  to receive attachment means, such as a bolt or pin  49  for attachment of guard member  21  thereto. Slots  46  provide lateral adjustment of guard member  21  relative return roller  11 . 
     As is best seen in FIG. 5, guard mounting brackets  61  are formed having a step shape with distal end  62  extending substantially horizontal and outwardly from conveyor system  10 . A vertical portion  63  extends downwardly from and normal distal end  62  ending at proximal end  64 . Proximal end  64  has a horizontal portion  65  and vertical portion  66 . Proximal end horizontal portion  65  extends inwardly towards conveyor system  10  and normal vertical portion  63  such that it is positioned between the upper surface of return idler bracket  13 , and conveyor system frame member  14 . Proximal end horizontal portion  65  has a plurality of holes substantially aligned with return roller attachment means  16  for securing guard mounting brackets  61  to conveyor system  10  without modification to conveyor system  10 . Proximal end vertical portion  66  extends downwardly from and normal proximal end horizontal portion  65  such that proximal end vertical portion  66  is in mating contact with the inner face of return idler bracket  13 . Proximal end vertical portion  66  has a vertical slot  67  which permits installation and attachment of guard mounting bracket  61  without the need to completely remove return roller  11  while avoiding interference with return roller shaft  15  rotation during operation of the conveyor system  10 . 
     Referring to FIGS. 2,  3 , and  4 , an optional feature of the present invention can be seen wherein support bars  31  and  32 , have a plurality of attachment points  36  for attachment of first  51  and second  52  wiper members. First wiper member  51  curves upwardly and outwardly from first guard member leg  22 , such that the distal end of first wiper member  51  is in substantially tangential alignment relative belt  12 . Second wiper member  52  curves upwardly and outwardly from second guard member leg  23 , such that the distal end of second wiper member  52  is in substantially tangential alignment relative belt  12 . First  51  and second  52  wiper members have a plurality of attachment points  53  for attachment to support bars  31  and  32 , by attachment means, such as a bolt or pin  54 . In the present embodiment, wiper members  51  and  52  are formed out of urethane and are adjusted in wiping contact with belt  12  by utilizing slot  44  adjustment capabilities. 
     It is to be understood that the form of the invention as shown herein is a preferred embodiment thereof and that various changes and modifications may be made therein without departing from the spirit of the invention or scope as defined in the following claims.