Abstract:
Secondary system for cleaning a belt running between conveyor pulleys comprised of a frame bar on which cleaning blades are mounted, two bracket assemblies to which the frame bar is adjustably mounted, and an adjustment system mounted on the external sides of the bracket assemblies. Bracket assemblies each can include a pair of slotted arms over which two or more clamps are joined together. Each bracket assembly can include an inner tube member that telescopes into two outer tube members and an upper member that can be adjustably clamped to the inner tube and a lower tube member to which the frame bar is mounted and attached to the upper member by the adjustment system. Frame bar and bracket assemblies have rectangular cross-section so that when mounted to each other, rotational movement of frame bar about its longitudinal axis is prohibited. This rotational prohibition is independent from the adjustment system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119(e) to Provisional Application Ser. No. 60/998,182, filed Oct. 9, 2007, incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to belt cleaning systems for conveyor belts and, particularly, to secondary belt cleaning systems. More particularly, this invention relates to an improved mounting system for a secondary belt cleaner that does not require a twister or “tensioner” for holding the cleaner blade or blades firmly against a moving conveyor belt. The mounting system of this invention places fine tuning adjusters on the outside or outer edges of a belt cleaner, much more accessible than the interior adjustment means of many prior art cleaners. 
     BACKGROUND OF THE INVENTION 
     It is known to use scraping style cleaners for a conveyor belt to remove debris and other materials from the belt. Such belts function in different capacities depending on their relative belt positions. Those belt cleaners positioned along the forward most belt head pulley are called primary belt cleaners. They are the first in line, meant to remove most of the “carry back” from the belt proper and are considered the most efficient means for effecting conveyor belt cleaning. Dual primary belt cleaners have been conceived and installed for some belt cleaning applications. 
     Further along the conveyor proper, past the belt head pulley, additional (or supplemental) belt cleaning can be accomplished with secondary cleaning systems. Such systems employ one or more metal blade components for removing additional carry back from the conveyor belt return, typically on the underside of same. It is also known to employ additional (tertiary) belt cleaners, belt wipers and/or other belt scraper devices as conditions may require. 
     For most secondary belt cleaner applications, it is critical that the blade components be held, in tension, against the moving conveyor for properly and effectively cleaning same. Numerous tensioner systems have been developed for applying a continuous, spring-like pressure (or tension) of the blades against the belt being cleaned. While most secondary cleaning systems today include an array of metal blades, the metal components of same are usually buffered by, or cushioned in a resilient, blade-holding base of rubber or other material for lessening rigid impact with the belt. Secondary cleaning systems may supplement the cleaning from one or more primary systems. But none of these systems should be so stiff as to risk damaging the belts they are meant to clean “near continuously”. 
     In many situations, the means for holding a secondary system firmly against the conveyor need not be overly sophisticated. Some elaborate tensioner devices are mechanically complex, costly to install, maintain and replace, and vulnerable to attack from the elements. 
     Accordingly, there is a need for a secondary conveyor belt cleaner that is better optimized for cleaning efficiency and cleaning blade wear resistance while not requiring complex cleaner mounting mechanicals. Further, a less sophisticated mounting means should apply proper blade cleaning pressures to the belt it is installed against, but without elaborate, springs and other tensioning systems. Such a simpler, yet still efficient mounting system should be capable of installation from multiple directions, for push-up or pull-up mounting. It would be beneficial if a simple secondary belt mounting means was conceived which could be readily adjusted from at or near the outer edges, rather than the more tedious, inside adjustments required by other secondary belt mechanisms. Preferably, this mounting system is used in conjunction with a rectangular (rather than circular) cleaning blade frame with multiple blade mounting crossbar members extending upwardly from one side of same. 
     SUMMARY OF THE INVENTION 
     In accordance with one preferred embodiment, a secondary belt cleaner and mount is provided having a main blade frame held firmly against the conveyor at opposite ends with side brackets. In one embodiment, each side bracket has two or more slotted arms extending from a base, either upwardly or downwardly depending on the direction of cleaner installation against the belt. These slotted arms are held together, on both sides of the conveyor, with at least two adjustable C-clamps. A first C-clamp (on each side) is bolted through a slot in the side bracket arm before the main cleaning blade frame is positioned against the conveyor belt and over both first C-clamps. A second (usually lower) C-clamp, also on both sides of the conveyor, fits around both slotted arms behind (and usually, below) the first “upper” C-clamp. These second C-clamps, like the first, get bolted through the slotted arms to the mounting means proper. 
     Preferably, both C-clamps are open-ended but still more box-shaped than curvilinear. With at least three, substantially straight sides, the C-clamps can be pushed into place from the sides of the slotted arms to which they will be bolted. Opposite the “open” end of such C-clamps, there is an outwardly projecting lip or ledge. The lip/ledge to the first and second C-clamps are meant to align when duly installed over their respective slotted arms. Once aligned, the outer lip/ledges of the first and second C-clamps can be interconnected by still other, finely adjustable means. In one particular embodiment, one of the two C-clamp lip/ledges has a threaded aperture through which a bolt passes before contacting the non-apertured lip/ledge of the other partnered C-clamp lip/ledge. In this manner, by rotating the threaded bolt, in one direction or the other, the spacing between C-clamps of this secondary cleaner mount can be finely adjusted affecting a better positioning of the main blade frame against the conveyor belt, from either or both sides. 
     In another embodiment, the slotted arms and C-clamp members are replaced by a pair of telescoping structural tube bracket assemblies that each are slotted through two opposing side for interaction with a bolt that holds outer tube members to an inner tube member and allows for adjustment of frame positioning insofar as the frame is mounted on the lower, outer tube member. In addition, the upper and lower outer tube members of the telescoping structuring tube bracket assembly can be adjusted in respect to each other by a bolt or screw adjustment system that interacts with both outer tube members. The main blade frame is attached to the lower external tube and can be adjusted as the position of the two outer tube members is adjusted. 
     In addition, for less rotational possibilities within this invention or a typical clamped and tensioned secondary cleaner mount, preferred embodiments of this invention include a rectangular, more preferably square-shaped, cleaning blade frame. For better engagement with the conveyor belt being cleaned, this rectangular blade frame has two or more mounting crossbar connectors extending upwardly and outwardly from one side. Such mounting is significantly improved in terms of blade contact and sweep when compared with the circular blade frames of the prior art from which only one crossbar connector projects upwardly and outwardly. A main advantage of mounting rubber blades mount between two crossbar connectors atop the blade frame, as opposed to bolting through only one upwardly extended crossbar, is that prior art single connector arrangements apply less forces against the conveyor for fine adjustment at the point of tangency, i.e., where the belt leaves the head (or front) pulley. Preferably, the blades that perform secondary cleaning should push into the conveyor belt about ⅛″ inch or more. Once the conveyor begins running, the cleaning blades will flex back and forth via their rubber mounts. On a single crossbar connector, these blades may fold over too often and too easily. And with excessive “fold over” and “over movement”, the rubber holders of a one blade connector frame are more prone to crack at their weakest points rendering them useless for continuous conveyor belt cleaning. And while these rubber blade holders can be replaced, their replacement is costly in terms of materials and productivity. With the preferred, two crossbar configurations of this invention, rubber blade mount breakage is less likely to happen. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of cleaner mount according to the invention with the cleaning blade frame and several cleaning blades situated therein; 
         FIG. 2  is a front view of a cleaner mount with the mounting base reversed for a push-up type arrangement against a conveyor belt B; 
         FIG. 3  is a perspective view of the left side cleaner mount from  FIG. 1  showing the cleaning blade frame in partial cutaway; 
         FIG. 4  is a left side elevational view of the cleaner mount as would be seen from lines IV-IV of  FIG. 3 ; 
         FIG. 5  is an enlarged front view of the left side cleaner mount from  FIG. 1  with the cleaning blade frame and several cleaning blades in partial cutaway; 
         FIG. 6  is top view of the cleaner mount, partial cleaning blade frame and several cleaning blades from  FIG. 5 ; 
         FIG. 7  is a perspective view of the left side cleaner mount from  FIG. 1  with the cleaning blade frame removed for illustrative purposes; 
         FIG. 8  is a top view of the left side cleaner mount from  FIG. 7 ; 
         FIG. 9  is a front view of a preferred rectangular cleaning blade frame for use with the present invention; 
         FIG. 10  shows top and side views of the cleaning blade frame from  FIG. 9 ; 
         FIG. 11  is a top view of the first and second C-clamp components for one preferred embodiment of this invention; and 
         FIG. 12  is a front view of the first and second C-clamps from  FIG. 11  with the adjustment bolt to be used for joining said C-clamps together. 
         FIG. 13  is a perspective view of another embodiment of the cleaner mount according to the present invention. 
         FIG. 14  is an exploded view of the cleaner mount from  FIG. 13 . 
         FIG. 15  is a perspective of one side of the cleaner mount from  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In  FIGS. 1 through 12 , a secondary cleaning system  10  for a conveyor belt in accordance with one preferred embodiment of this invention is illustrated. The cleaning system, generally  10 , includes a pair of side brackets  12  and  14  for positioning on either side of a conveyor belt, shown for relative positioning as component B in  FIG. 2 . Each side bracket  12  and  14  has a mounting base  16  from which a pair of slotted arms  18  outwardly extends. The slots  20  in each slotted arm pair  18  align for receiving one or more bolts to connect other cleaner mount components to the side brackets  12  and  14 . 
     The slotted arms  18  of preferred embodiments are spaced apart a set distance that should approximate the width of a cleaning blade, frame bar  22 . As best seen in  FIGS. 9 and 10 , frame bar  22  is rectangularly shaped, preferably square in cross section. One embodiment of frame bar  22  is made from a hollow metal extrusion. With a non-circular cross-section, frame bar  22  will not rotate between surrounding frame components thereby adding some directional integrity to the plurality of cleaning blades positioned on that frame bar  22 . 
     The value of a hollow square channel for frame bar  22  is threefold: first, a flat channel will not spin backwards (a round bar, held on by pipe clamps like some prior art devices, is more prone to spinning and, hence, more difficult to install and require more maintenance. Secondly, for some heavier duty applications, a pipe can be further run through the middle of this preferred hollow square channel to frame bar  22 . In that manner, strength may be added to said frame bar as the need arises. A central reinforcement to the outer, square bar can be easily made and shipped. The center reinforcement “rod” can be secured with a bolt on each end, even while the rest of this cleaner is installed, and running. Thirdly, with the aforementioned frame size and shape, a smaller width profile cleaner is possible. By eliminating the need for bulky pipe clamps, the cleaner of this invention can be mounted into smaller, tighter areas including those under the “return side” of an industrial conveyor belt. This design is thinner than prior art equivalents by several inches. And with external adjustment, this invention avoids the problem of most pipe clamp designs which have their adjusters located in the tightest areas to access once they are installed on the conveyor proper. 
     Extending upwardly from a flat plane, typically the top surface  24  of frame bar  22 , are two or more mounting crossbar connectors  26 . Preferably, these connectors  26  have a plurality of apertures  28  for bolting to an array of several cleaning blades  30 . The blades  30  depicted in  FIGS. 1 ,  2 ,  5  and  6  are illustrative only. Each blade  30  has a rubberized base  32  from the top of which a metal component  34  extends for scraping the surface of a conveyor belt against which metal component  34  is tensioned. Preferably, metal component  34  is a tungsten carbide element having a purposefully pitch, or angled top. The blade can also be coated, with a tool coating for example, to improve and reduce the need for and cost of replacements. Rubberized base  32  is preferably comprised of urethane, although other rubber products can be used. 
     As a further alternative, a crush limiter system can be used to help attach the metal blade components to the base and the base to the frame so that the connecting bolts are not over tightened (whereby the base is “crushed”). In particular, as shown in  FIG. 14 , metal blade components  34  are attached to bases  32  and bases  32  are attached to connector  26  by use of threaded bolts  90  and nuts  91 . Bolts  90  and nuts  91  pass through crush limiting sleeves  92  that, in turn, pass through the apertures in the metal components  34 , base  32  and connector  26 . Sleeves  92  are made of a solid material and have a defined length that limits the ability of nuts  91  to screw into and crush base  32 . Limitation on the movement of bolts  90  can also be provided by limiting the length of the threading on the bolt. 
     Referring to  FIGS. 1 through 8 , a pair of C-clamps joins together each side bracket  12  and  14  according to this invention.  FIGS. 11 and 12  depict one preferred embodiment of C-clamps. As shown, there is a first, or upper C-clamp  40 , beneath which is situated a second, or lower clamp  42 . Both clamps are straight edged for better fitting against the outside edges of side brackets  12  and  14 . In an alternative embodiment, not shown, C-clamps could be made more boxlike and not open-ended. Such an alternative clamping means would require installing over the slotted arms of each side bracket  12  and  14  before being raised or lowered in place for mounting. Afterwards, a fully boxed clamp could be slid vertically along the side bracket pair it is connecting, but not move horizontally, laterally, or otherwise fully separate from said side bracket pair. 
     As seen in  FIGS. 11 and 12 , clamps  40  and  42  each have an aperture  44  through which a threaded bolt  46 , washer  47  and nut  48  (see  FIG. 1 ) are cumulatively used for attaching same through the slot  20  (see  FIG. 1 ) in each respective side bracket  12  and  14  (see  FIG. 1 ). Clamps  40  and  42  further interconnect to one another, external to the conveyor belt mounting system proper. Particularly, upper clamp  40  has an external ledge or lip  50  with a correspondingly positioned ledge or lip  52  on the exterior to lower clamp  42 . Preferably, one of those two lips has a threaded aperture  54  through which a bolt  56  extends for finely adjusting the distance clamp  40  is spaced from clamp  42 . By gradually turning bolt  56  in one direction or the other, the relative position of frame bar  22  against the conveyor belt can be manually adjusted. More importantly, such adjustments can be performed from a region external to the conveyor belt, while the belt is in motion. In this manner, the invention may keep the blades  30  on its frame bar  22  duly tensioned against the belt, without the need for spring-like tensioner systems of the prior art. In alternative embodiments, both upper clamp lip  50  and lower clamp lip  52  may be threaded for extending threaded bolt  56  there through. Still other interconnecting means may be employed for finely adjusting the preset gap between the uppermost ledge  60  (see  FIG. 1 ) of upper clamp  40  against which the lower end of frame bar  22  “rides”. 
       FIGS. 13-15  show an alternative embodiment of the present invention wherein the slotted arms and C-clamp bracket design are replaced by a pair of telescoping structural tube assemblies or brackets  71  and  75  that serve as a mount for the main blade frame bar  22  and allow for adjustment of frame positioning. In particular, each telescoping structuring tube assembly or bracket  71  and  75  is comprised respectively of inner tube members  72  and  76  that slidably telescopes into upper tube members  73  and  77 , respectively, and lower outer tube members  74  and  78 , respectively. The main blade frame bar  22 , along with blades  30 , bases  32  and metal components  34  remain the same in each embodiment. Tubular mounts  81  and  86  are attached, respectively, to lower outer members  74  and  78  and receive the ends of frame bar  22  so as to mount frame bar  22  to lower outer members  74  and  78 . Preferably, tubular mounts  81  and  86  have a rectangular cross section and thereby interact with the rectangular cross section of frame bar  22  to prevent rotation of the frame bar  22  and the attached blades  30 . 
     Inner tube members  72  and  76  each have a slot  80  and  85 , respectively, on the sides of these members that faces mount frame bar  22 , as well as slots on the opposite sides of members  72  and  76 . Slots  80  and  85  and the opposite slots on the back of members  72  and  76  allow clamping bolts  82  and  87  to pass through inner tube members  72  and  76  and upper tube members  73  and  77  respectively and attach these upper tube members  73  and  77  to these inner tube members  72  and  76 . Slots  80  and  85  allow for adjustment of the position of upper tube members  72  and  76  before they are secured to inner tube members  73  and  77 . 
     Lower tube members  74  and  78  slide on inner tube members  72  and  76  and the position of the lower tube members  74  and  78  in respect to upper tube members  73  and  77  is adjusted by for that can be adjusted in respect to each other by a bolt or screw adjustment that interacts with both outer tube members. The main blade frame bar  22  is attached to the lower tube members  74  and  78  and can be adjusted as the position of the two outer tube members  73  and  77  is adjusted by adjustment systems  83  and  88 . Referring to  FIG. 15  as an example, adjustment system  83  is comprised of mounts  83   a  and  83   b  that are attached to upper and lower tube members  73  and  74 , respectively. Threaded bolt or screw  85  passes through mounts  83   b  and threadably attaches to mount  83   a  such that turning of bolt or screw  85  causes the horizontal location of mount  83 b, along with lower tube member  74  and frame bar  22  to adjust. This same operation applies to adjustment system  88  and lower tube member  78 . Adjustment systems  83  and  88  are preferably mounted on the outside of tube assemblies  71  and  75  and away from the blades  30  mounted on frame bar  22 . This allows for fine adjustment of the frame position and is easily accessed by a user. Also this adjustment means is independent of the means by which frame bar  22  is mounted to the tube assemblies  71  and  75  (and the anti-rotation mounting system associated therewith). 
     Significantly, in this second embodiment, the tube brackets can be mounted upright or upside down thereby allowing for a universal application. Preferably the tube brackets are comprised of metal, such as steel or steel alloys. 
     While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.