Abstract:
The present invention is directed to a conveyor belt cleaning apparatus comprising a frame having a front side, a rear side, two lateral sides and one or more openings located between the front side, the rear side and the lateral sides; a first scraping blade and a second scraping blade, wherein each of the scraping blades is positioned between the lateral sides of the frame, and wherein the second scraping blade is rearward of the first scraping blade; and means for securing the frame to the underside of a conveyor belt assembly such that the first scraping blade and the second scraping blade make contact with the conveyor belt of the conveyor belt assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to conveyor belt cleaning apparatus for attachment near the discharge end of a conveyor belt assembly for cleaning away debris adhering to the conveyor belt. 
     2. Description of Related Art 
     A primary function of conveyor belt cleaners is to remove debris that remains on the conveyor belt after the belt has rounded the drum at the discharge end of the conveyor (i.e., “carry-back debris” or simply “carry-back”) so as to cause the conveyor belt apparatus malfunction or clog. The main drawback of previously known conveyor belt cleaners is that either they do not remove sufficient “carry-back” from the underside of the conveyor belt or that the debris removed tends to accumulate on the body and/or blade of the cleaner itself and thereby reduces its effectiveness. In either case, the conveyor operation must be stopped repeatedly so that maintenance operations can be performed to allow service personnel to clean the conveyor belt or the conveyor belt cleaner, as the case may be. 
     U.S. Pat. No. 5,014,844 describes a conveyer belt cleaner that is made of body and a plurality of cleaner elements attached side by side to the body. Each cleaner element has a blade, a blade holder attached to the body and a torsion spring located between the blade and the blade holder. The blade consists of an upper part that is pressed against the underside of the conveyer belt and a lower part that is attached to the torsion spring. The described conveyor belt cleaner consists of a single row of cleaning blades. 
     U.S. Pat. No. 5,222,589 describes a conveyer belt cleaner that consists of a single blade. The blade is curved and positioned at the underside of the discharge end of the conveyer belt. The curved shape of the blade not only scrapes the conveyer belt but also protects against the blade damaging the belt. 
     U.S. Pat. No. 5,031,710 describes a conveyer belt cleaner that is attached to the belt and employs the use of a scraper and several nozzles that dispense liquid. A beam that acts as a liquid reservoir carries liquid from a liquid source to the nozzles. Theses nozzles are placed transversely below the conveyer belt along with the scraper. The liquid is sprayed to remove debris from the conveyer belt before the scraper removes carry-back debris. 
     U.S. Pat. No. 4,269,301 describes a conveyer belt cleaner that consists of three scraper blades positioned against a conveyor belt at the discharge end drum. Each blade is secured to an operating lever which may be rotated by an air cylinder and thereby flex the scraper blade against the conveyor belt. The pressures in the three separate air cylinders are adjusted so that the first scraper blade receives the greatest flexing force, the second scraper blade a lesser flexing force, and the third scraper blade the least flexing force. The differential flexing forces is accomplished by supplying the air cylinders through progressively differently set pressure reducing valves connected to a common compressed air main. 
     Thus, there exists a need for a simple, conveyer belt cleaner without moving parts or power supply that effectively removes carry-back debris without itself requiring frequent maintenance to remove accumulated debris. The present invention substantially fulfills this need. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a conveyor belt cleaning apparatus comprising a frame having a front side, a rear side, two lateral sides and one or more openings located between the front side, the rear side and the lateral sides; a first scraping blade and a second scraping blade, wherein each of the scraping blades is positioned between the lateral sides of the frame, and wherein the second scraping blade is rearward of the first scraping blade; and means for securing the frame to the underside of a conveyor belt assembly such that the first scraping blade and the second scraping blade make contact with the conveyor belt of the conveyor belt assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
         FIG. 2  1 is a top view of a conveyer belt cleaning apparatus of the invention. 
         FIG. 2  is an enlarged view of scraping blade of the invention. 
     
    
    
     In the following description of the invention similar reference characters refer to similar parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
       FIG. 1  shows Conveyer belt cleaning apparatus  100  of the present invention. Frame  105  has forward side  130 , rearward side  140  and lateral sides  150 . First scraping blade  110 , which includes a base  114  and a plurality of fingers  118 , is secured to forward side  130  using a mounting plate  170  and mounting plate bolts (not shown). As shown, conveyor belt cleaning apparatus  100  includes a plurality of first scraping blades  110 , positioned side-by-side, secured to forward side  130 . Second scraping blade  120 , which includes a base  124  and a plurality of fingers  128 , is secured to rearward side  140  using mounting plates  170  and mounting plate bolts  172 . Likewise, as shown, conveyor belt cleaning apparatus  100  includes a plurality of second scraping blades  120 , positioned side-by-side, secured to rearward side  140 . In operation, frame openings  160  allow debris removed from the conveyor belt by first scraping blade  110  to fall through frame  105  and thereby not accumulate on frame  105 . 
     Conveyor belt cleaning apparatus  100  further includes a pair of frame mounting assemblies  200 , which facilitate mounting frame  105  to a conveyor belt. Each frame mounting assembly  200  includes a frame support tube  210  secured to frame  105 , a mounting arm  220  secured to frame support tube  210  and a support tube bracket clamp  230  secured to mounting arm  220 . Mounting bracket  240  is secured to mounting arm  220  by support tube bracket clamp  230  and to the conveyor belt using mounting bracket bolt holes  248  and bolts (not shown). Clamp attachment openings  244  facilitate proper adjustment of first and second scraping blades  110  and  120 , respectively, against the conveyor belt. 
     Frame  105  may be made of any suitable material including, for example, steel, aluminum, carbon graphite, iron or combinations thereof. In one embodiment frame  105  is made of stainless steel. In another embodiment frame  105  is made of aluminum. In still another embodiment frame  105  is made of carbon graphite. In yet another embodiment frame  105  is made of iron. 
     Frame  105  may include or more frame openings  160  which allow debris removed from the conveyor belt by first scraping blade  110  to fall through frame  105  and thereby not accumulate on frame  105 . In certain embodiments frame  105  has one frame opening  160 , while in other embodiments frame  105  has a plurality of frame openings  160 . In one such embodiment frame  105  has two frame openings  160 . The size and orientation of frame openings  160  should be such as to maximize debris clearance from frame  105  without having a significant adverse effect on the strength of frame  105 . 
     The size of frame  105  may vary in accordance with the size of the conveyor belt to be cleaned. Typically, frame  105  is from 4 inches to 24 inches in length (i.e., from front to back) and from 12 inches to 96 inches in width (i.e., from side to side). In one embodiment frame  105  is from 8 inches to 16 inches in length and from 24 inches to 48 inches in width. In one such embodiment frame  105  is from 8 inches to 16 inches in length and about 24 inches in width. In another such embodiment frame  105  is from 8 inches to 16 inches in length and about 32 inches in width. In still another such embodiment frame  105  is from 8 inches to 16 inches in length and about 40 inches in width. In yet another such embodiment frame  105  is from 8 inches to 16 inches in length and about 48 inches in width. In certain such embodiments frame  105  is from 10 inches to 12 inches in length. For example, in one embodiment wherein frame  105  is 11 inches in length and 32 inches in width, frame  105  has two frame openings  160  located 1 inch apart from each other and each being 6 inches in length by 12 inches in width. 
       FIG. 2  is an enlarged view of scraping blade  110  of the present invention. Scraping blade  110  includes base  114  and fingers  118 , and is attached to frame  105  using a pair of mounting plates  170  and mounting plate bolts  172  (see  FIG. 1 ). Base  114  includes a pair of mounting plate bolt holes  116 . 
     Scraping blades  110  and  120  may be made from any suitable flexible material having a durometer rating between 60 and 100. Ideally, such materials also are easily pourable into a mold at elevated temperatures and solidify upon cooling to room temperature. Such materials include, for example, polyurethane, rubber and mixtures thereof. In one embodiment each of scraping blades  110  and  120  is made of polyurethane. In one embodiment each of scraping blades  110  and  120  has a durometer rating of from 65 to 95. In one such embodiment each of scraping blades  110  and  120  has a durometer rating of from 85 to 95. In one such embodiment each of scraping blades  110  and  120  has a durometer rating of about 90. 
     As mentioned above, conveyor belt cleaning apparatus  100  may include a plurality of first scraping blades  110  positioned side-by-side, and a plurality of second scraping blades  120  similarly positioned side-by-side. Each scraping blade may be from 4 inches to 24 inches in width and from 4 inches to 16 inches in length. In one embodiment scraping blades  110  and  120  are 8 inches in width by 8 inches in length. In another embodiment scraping blades  110  and  120  are 12 inches in width by 8 inches in length. In still another embodiment scraping blades  110  and  120  are 12 inches in width by 12 inches in length. 
     As mentioned above, first and second scraping blades  110  and  120 , respectively, are comprised of a base and a plurality of fingers. In certain embodiments the base and the corresponding plurality of fingers of a scraping blade are equal in length. Thus, in one embodiment scraping blades  110  and  120  are 8 inches in length by 8 inches in width, wherein the base of each of the blades is 4 inches in length and the corresponding fingers also are 4 inches in length. In certain embodiments the base of a scraping blade is greater in length than its corresponding fingers, and in other embodiments the fingers of a scraping blade are greater in length than their corresponding base. The distance between the fingers of a scraping blade may be from one-sixteenth of an inch to one-fourth. In one embodiment the distance between the fingers of scraping blades  110  and  120  is one-eighth of an inch. In another embodiment the distance between the fingers of scraping blades  110  and  120  is one-tenth of an inch. In another embodiment the distance between the fingers of scraping blades  110  and  120  is one-twelfth of an inch. The thickness of the scraping blades may be from one-eighth of an inch to 1.5 inches. In certain such embodiments the present invention includes scraping blades having a thickness of one-fourth inch to one inch. In certain embodiments the present invention includes scraping blades having a thickness of one-fourth inch to three-fourths inch. In one such embodiment the present invention includes scraping blades having a thickness of one-half inch. 
     In operation, the fingers of first and second scraping blades  110  and  120 , respectively, contact the conveyor belt surface and specifically the cleated portion of the conveyor belt as the belt passes over conveyor belt cleaning apparatus  100 . This effectively brushes much of the carry-back debris that is adhered to the conveyor belt to be removed from the conveyor belt before it returns to the loading zone, thereby reducing clogging and potential safety hazards for workers. 
     While particular embodiments of the present invention have been shown and described herein for purposes of illustration, it will be understood that the invention is not limited thereto. Modifications may be made by persons skilled in the art, particularly in light of the foregoing teachings, without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. 
     All of the U.S. patents and published U.S. patent applications referred to in this specification are incorporated herein by reference in their entirety to the extent not inconsistent with the present description.