Abstract:
A conveyor belt cleaning device which can handle conveyor belts with damaged areas, mechanical joints, and/or head pulleys with profile spaces causing the conveyor belt to run unevenly, is provided. The scraper blade is attached to a T-shaped element which has pressure applied by an air bladder held within a housing. The T-shaped element moves freely within the housing to permit movement of the scraper blade in a direction tangential to as well as perpendicular to the conveyor belt.

Description:
TECHNICAL FIELD  
       [0001]    The invention relates to the field of scrapers and cleaners for conveyor belts which remove conveyed material which has adhered to the belt on the return path. 
       BACKGROUND  
       [0002]    Conveyor belts are used to move or convey bulk particulate materials. A conveyor belt consists of a face side and a back side. The face side receives the load of product at a load point and carries the product in the conveying direction to a discharge point where the product is then unloaded. A product residue may adhere to the belt, build up over the span of the conveyor belt face, and release onto return rolls and may then drop to the ground and/or body of water. The back side of the conveyor belt is not designed to carry product. The conveyor belt rides on rollers or a deck attached to a conveyor system structure that is ridged, with a starting point (usually a tail pulley) and an ending point (a head pulley). The conveyor belt may have a mechanical joint or a non-profiled seam, to create an endless belt with no start or end. The conveyor belt runs uniformly around the tail pulley and the head pulley, supported between the two pulleys by a deck or rollers on the top face and carrying rolls on the bottom return. With the transfer of product residue to the conveyor structure, a residue build-up can occur causing belt shifting, and resulting in damage to the belt, structure, and/or rollers. 
         [0003]    To address the foregoing problem, scrapers or cleaners are provided to scrape and clean the belt immediately following the discharge point on the head pulley. This has been addressed previously by providing a spring-mounted blade in contact with the belt. A challenge that such current cleaners face is the ability to clean the surface of a belt that contains irregularities or reverses direction. Conveyor belts may have uneven surface wear, mechanical joints or have had cuts patched with rip plates, and there may be abnormalities on the head pulley. Current scrapers and cleaners do not have the ability to handle such irregularities. U.S. Pat. No. 4,290,520 to Rhodes discloses a conveyor belt cleaning device in which the pressure on the scraper blade is applied by a pressurized bag, however the scraper blade can only slide in one direction in the housing and is not free to move in the direction tangential to the surface of the conveyor belt. There is a need therefore for a belt cleaner that can divert product residue off the face of a belt at the off loading point, even if the surface of the head pulley contains ridges and irregularities, or where the belt surface has irregularities such as laced joints, rip plates, and patch repairs, or where the belt reverses direction. 
         [0004]    The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
       SUMMARY  
       [0005]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
         [0006]    The invention provides a conveyor belt cleaning device which can handle reversing conveyor belts and conveyor belts with damaged areas, mechanical joints, and/or head pulleys with profile spaces causing the conveyor belt to run unevenly. The scraper blade is attached to a T-shaped element which has pressure applied by an air bladder held within a housing and which moves freely within the housing to permit movement of the scraper blade in a direction tangential to, as well as perpendicular to, the surface of the conveyor belt. 
         [0007]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS  
         [0008]    Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
           [0009]      FIG. 1  is a front perspective view of the scraper of the invention. 
           [0010]      FIG. 2  is a rear perspective view of the scraper shown in  FIG. 1  with the support bar removed. 
           [0011]      FIG. 3  is a front perspective view of the scraper shown in  FIG. 1  with the cleaning element removed. 
           [0012]      FIG. 4  is a front cutaway view of the scraper shown in  FIG. 1 . 
           [0013]      FIG. 5  is a detail perspective view illustrating the T-bar element in a first position. 
           [0014]      FIG. 6  is a detail perspective view illustrating the T-bar element in a second position. 
           [0015]      FIG. 7  is a cross-section view of the scraper shown in  FIG. 1 . 
       
    
    
     DESCRIPTION  
       [0016]    Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
         [0017]    With reference to  FIG. 1-4 , conveyor belt scraper  40  comprises an air bladder housing  14  having end caps  21 , scraper blade  5  mounted on mounting plate  31 , attachment bar  10  and urethane shields  6 . Housing  14  is preferably made of a two-inch by four-inch rectangular steel tube. The end caps  21  are welded on the ends of the steel tube  14  and each end cap has holes  22  for receiving bolts for mounting the scraper  40  to the conveyor. 
         [0018]      FIG. 4  and  FIG. 7  illustrate the different elements of the scraper in cutaway view and cross-section. The housing  14  ( FIG. 1 ) has a lengthwise slot  4  ( FIG. 7 ) which may be divided into two or more slots depending on the length of area to span. Preferably the length of housing  14  is greater than the width of the conveyor belt for which the scraper will be used, preferably about six inches greater. The ends of slot  4  are preferably spaced inwardly from each end of the housing  14 , for example starting five inches from one end of housing  14  and three inches from the other. Slot  4  runs down the center of the top surface of housing  14 . Housing  14  contains air bladders  7 , air manifold  15 , base pad  8  and T-bar  30 , the mounting plate  31  portion of which extends up through slot  4 . Dust shield  11  and bracket  12  are provided on housing  14 . 
         [0019]    The T-bar  30  ( FIG. 3 ,  7 ) is made up of three elements: mounting plate  31 , base  32 , and spacer  33 . Mounting plate  31  extends through the slot  4  of the housing  14  and serves as the means to hold the scraper blade  5  and the urethane shields  6 . Spacer  33  is a flat bar, for example measuring three quarters inch wide by quarter inch thick steel. The length of spacer  33  is preferably slightly less than the length of the scraper blade  5 , for example by about 2 inches. Spacer  33  acts as a spacer and the contact point to the air bladder  7 . Spacer  33  is welded down the center of base  32 . Base  32  is a flat bar, for example measuring one and half inch wide by quarter inch thick steel having the same length as spacer  33 . The purpose of spacer  33  and base  32  is to form the base of the T-bar  30 . Mounting plate  31  is a flat bar, for example measuring three inches wide by one-quarter inch thick steel having the same length as base  32  and spacer  33 . Mounting plate  31  is welded on edge, perpendicular down the center of base  32 . As shown in  FIG. 4 , a steel tab  34 , for example about two inches long by one inch wide by one-quarter inch thick, may be formed on mounting plate  31  such as by welding to the side and level with the top edge of plate  31 . This permits the scraper blade  5  to extend over a greater length and be centered on the housing  14  notwithstanding that a portion of the housing is occupied by the air manifold  15  and connection to air bladder  7 . T-bar  30  has a series of bolt holes  9  ( FIG. 3 ) drilled along the upper edge of mounting plate  31  for attaching the scraper blade  5 . 
         [0020]    T-bar  30  acts as the mounting bracket to which the scraper blade  5  ( FIG. 1 ), urethane shield  6  ( FIG. 1 ,  2 ), and attachment bar  10  ( FIG. 1 ) are attached. As shown in  FIGS. 5 and 6 , when under pressure from the conveyor belt and any irregularities, the T-bar  30  presses against the side wall of housing  14  at A or B and one side near the slot  4  causing a pinch point C or D, allowing the T-bar  30  to tilt slightly forward or back, as represented in  FIGS. 5 and 6 , by an angle E from the vertical which is typically 3 to 5 degrees but may be as much as 10 degrees depending on the dimensions of the belt and scraper and type of application, and the extent of inflation of air bladders  7 . The T-bar  30  has little resistance along the flat walls of housing  14  and with the pressure provided by the air bladder  7 , the T-bar  30  floats independently, with the ability to travel up and down as well as pivot back and forth enabling it to clean a belt that reverses and react to the obstacles that a conveyor belt may encounter. Similarly the mounting plate  31  can travel up and down, without any external bracing on the mounting plate  31 . The T-bar cannot be removed from the housing  14  and is the only element to which the scraper blade  5  is bolted. 
         [0021]    The slot  4  ( FIG. 5-7 ) allows the T-bar  30  to glide up and down, and pivot forward and back. Pulleys containing slide lag, with spaces missing in between and clips holding rips together, do not prevent the scraper from cleaning the conveyor belt surface due to the ability of the T-bar to pivot back and forth. The slot  4  may be, for example, five-sixteenth of an inch wide and cut along the center of the top side of the housing  14 . When used on a conveyor belt greater than thirty-six inches wide, the slot  4 , preferably is split by a one inch bridge of steel which is left between the two sections of slot  4  to maintain the strength of the housing  14 . 
         [0022]    The air bladder  7  ( FIG. 4 ,  7 ) consists of a single bladder folded in half and connected at its ends to air manifold  15 . Air bladder  7  may be constructed for example of one-inch diameter rubber hose. Air manifold  15  which connects to the air in-take mounting bracket  13  to create a double lift system inside the housing  14 . The air bladder  7  spans the length of the housing  14 . The interior base pad  8  ( FIG. 4  and  FIG. 7 ), is a 1.5 inches wide by ½-inch thick rubber material. The interior base pad  8  acts as a spacer and noise damper. It lies along the interior base of the housing  14 . 
         [0023]    The air intake mounting bracket  13  ( FIG. 4 ) is a connector that allows the air supply to be attached to the air bladder  7 . The air intake mounting bracket  13  is preferably positioned on the opposite side of housing  14  in relationship to the slot  4  adjacent an end of housing  14 . The air intake mounting bracket  13  has an air inlet valve that protrudes through a slot and locks in place by mean of a lock nut onto the housing  14 . An air hose (not shown) with a threaded fitting is connected to the air intake valve on the air intake mounting bracket  13  allowing an air pump or regulated controlled air source to be attached to provide air under pressure. A relatively low pressure, such as 5 psi, is sufficient and may be provided by a hand pump such as a bicycle tire pump. Other pressurized fluids, such as hydraulic fluid, may also be used in the bladder  7 . 
         [0024]    The scraper blade  5 , mounted on the T-bar  30  by means of bolts through holes  19 , is the blade or pad that is kept in contact with the face side of the conveyor belt that causes the residue to be removed from the belt. Its construction will vary depending on the application, but it will typically be a rigid rubber material which may have a steel tip for certain applications. Typically it will measure about three inches in height, one-inch in thickness, with its length determined by the conveyor belt width. As the scraper blade  5  wears away, the T-bar  30  extends a maximum height above slot  4  when base  32  contacts the top surface of the interior of housing  14 , for example 1.5 inches, leaving ½-inch of scraper blade  5  so the steel of the T-bar  30  never comes in direct contact with the surface of the conveyor belt. This remaining ½ inch of scraper blade  5  ensures no damage will come to the conveyor belt or any mechanical fasteners on the conveyor belt if applicable and/or the T-bar  30 . Through use, the scraper blade  5  will wear down but can easily be changed. 
         [0025]    The scraper  40  uses two urethane shields  6  ( FIG. 1 ,  2 ) which are mounted on both sides of the T-bar  30 . One urethane shield  6  is secured by an attachment bar  10 , and the other is secured by three-eighth inch washers and nuts  37 . The urethane shields  6 , once fastened to the T-bar  30 , form a steep slope from the scraper blade  5  to prevent diverted residue from accumulating on the sides of the scraper  40 , eliminate build-up of waste and keep dust or debris from invading the unit. The urethane shields  6  are non-stick material flashing, preferably about six inches wide by one-eighth of an inch thick, formed of smooth, highly wear-resistant material such as urethane. They are provided with holes  39  with the same bolting holes pattern as holes  19  and  29  in the scraper blade  5  and the attachment bar  10 , and are held in place by the same bolts  35 . The length of the urethane shield  6  is determined by the width of scraper blade  5  and is preferably somewhat longer, for example one-inch longer than the scraper blade  5  such that the urethane shield  6  extends one-half inch past each end of the scraper blade  5  when installed on the T-bar  30 . Attachment bar  10  ( FIG. 1 ) may be, for example an inch wide and a quarter inch thick flat steel bar. It is drilled with the bolting holes  29  in the same arrangement as holes  9 ,  19  and  39 . It sandwiches one of the two urethane shields  6  and the scraper blade  5  between itself and the T-bar  30 . 
         [0026]    Scraper blade  5  is removably secured to mounting plate  31  by fasteners such as bolts  35  and associated washers and nuts  37 . The bolting holes pattern is a series of three-eighth inch diameter holes drilled preferably about three inches apart on the T-bar  30  (reference numeral  9  in  FIG. 3 ), the scraper blade  5  (reference numeral  19  in  FIG. 4 ), the attachment bar  10  (reference numeral  29  in  FIG. 4 ), and the two urethane shields  6  (reference numeral  39  in  FIG. 4 ). The bolting holes pattern  9  must line up on all of these components enabling three-eighth inch diameter bolts to secure all of these components to the T-bar  30 . As a result, under the drag and pressure of the scraper  40  in operation, the scraper blade  5  and urethane shields  6  will not pull apart. 
         [0027]    A dust shield  11  ( FIG. 3  and  FIG. 4 ) may be provided to keep dust and residue out of housing  14 . It may be a thin rubber material, such as about one-sixteenth inch in thickness, fitted tightly around the slot  4  creating a gasket seal between the T-bar  30  and housing  14 . It is held in place by a steel bracket  12  ( FIG. 3  and  FIG. 4 ), such as an angle iron steel bracket welded to the housing  14 . 
         [0028]    In operation, the scraper  40  is mounted on the conveyor adjacent wherever it is desired to divert the residue from the belt, such as at the discharge point. The air intake mounting bracket  13  is connected to the air supply and pressurized air is delivered to air bladders  7  to adjust the height and pressure of scraper blade  5  against the belt surface. Periodically the air pressure is increased as scraper blade  5  wears down, until it is necessary to remove scraper  40  to replace scraper blade  5 . 
         [0029]    The end caps  21  ( FIG. 1 ) are preferably rectangular five inch by four inch by quarter inch thick plate steel that have four equal holes spaced in each corner as slots. These slots, measuring one inch by half inch, are positioned a quarter of an inch in from the top and bottom and a quarter of an inch in from either side. The end caps  21  are welded to each end of the steel tube  14 . This weld goes down each side and across the top of the steel tube  14 . The end cap  21  functions as the mounting brackets for the scraper. 
         [0030]    By making housing  14  a two-inch by four-inch rectangular steel tube, preferably of three sixteenth-inch thick steel, the rigidity needed to span lengths up to one hundred inches is provided. On lengths greater than thirty-six inches on the cleaning blade width, a one inch bridge may be provided along the blade slot  4  to add more strength and to keep the square tube from distorting under the scraping action of the removal of product from the face of the belt. The end caps  21  are welded on the ends with a four bolt construction for mounting, so the scraper will not twist under the pressure and force required to clean the conveyor belt. 
         [0031]    The conveyor belt scraper according to the invention is therefore easy to install and maintain on conveyor systems. It can be used for many different diverting applications such as: i) reversing conveyor belts; ii) conveyor belts with head pulleys that have a welded on lagging resulting in gaps that the conveyor belt molds too as it travels; iii) laced joints in the conveyor belt; iv) steel plates that hold conveyor belt repairs together; v) used belts with uneven surfaces; vi) diverting carry back product, water or liquid off the conveyor belt; vii) removal of dry or wet residue. The invention has application to conveyor belts in the food industry, agriculture, waste products, recycling, airports, package handling, mill industry, mining or applications where conveyor belts have oil on them. 
         [0032]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.