Abstract:
A wiper blade for removing material from a conveyor belt attached to the conveyor belt frame near the nose roller such that the belt will not have material on the belt during the return portion of the loop. The wiper blade is easily attached to and removed from the conveyor frame for installing and replacing the wiper blades when they become worn. The wiper blade is slid out from its slot on the support bar and a new blade inserted into the slot and slid into a locking position for a quick and low cost change of blades. The support bar is rotatably attached to the conveyor frame to adjust the edge of the wiper blade to be proximate the conveyor belt. The wiper blade is made of an elastomeric material without any metal parts for ease of recycling.

Description:
BACKGROUND OF THE INVENTION 
   I. Field of the Invention 
   This invention relates generally to conveyor apparatus for transporting bulk materials and more particularly to a conveyor belt cleaner or scraper mechanism that is adapted to be deployed proximate the discharge end of the conveyor for cleaning away material adhering to the conveyor belt. 
   II. Discussion of the Prior Art 
   In many industries where granular material in bulk form must be transported from one point to another, it is common practice to utilize an endless flexible elastomeric belt that is entrained about a plurality of rollers where at least one of the rollers is motor driven to thereby carry the belt in an orbital path about a frame structure in which the rollers are journaled. The products deposited on the belt are carried by it to a discharge location where the material is allowed to fall from the belt as the belt traverses the conveyor&#39;s nose roller. 
   It can be appreciated that with some materials there may be a tendency for them to adhere to the belt and be carried beyond the desired discharge. This causes material to be deposited underneath the conveyor and causes expensive cleanup and unnecessary wear and tear on conveyor rollers and other components. In dealing with this problem, one solution has been to provide an elongated scraper blade usually made of rubber or urethane. Other materials such as metals are also used to scrape material from the conveyor belt surface. When using an elastomer scraper or blade, the blade is typically attached to a steel bracket or tube that extends transversely across the width dimension of the endless belt proximate the nose roller of the conveyor. The blade is allowed to rub against the moving conveyor belt with a predetermined force to thereby remove the majority of the bulk product that would adhere to the conveyor belt. Because of the frictional engagement, the scraper blade is subject to wear and may require frequent spatial adjustment and ultimately replacement. Sometimes two or more scrapers will be used one after another to do a more efficient job of cleaning the belt. Keeping conveyor belt cleaners maintained can be costly for a plant or mine operator not only because of the maintenance time involved but because some of the conveyor belt cleaner replacement blades are quite expensive. 
   In the past, various ways have been devised for mounting conveyor belt cleaners or scrapers to the frame of a conveyor at a location proximate the nose roller thereof. 
   Several manufacturers such as Martin Engineering, Asgco, Argonics, and Flexco provide belt cleaners that consist of a mainframe of either square or round tubing. A flange is typically welded to the tubing and pins are used to attach the belt cleaner to the flange. One of the described cleaners is manufactured by Martin Engineering and assigned U.S. Pat. No. 4,917,231. Typically the cleaning blades used in the most popular cleaners such as those previously mentioned consist of an aluminum extrusion molded into the polymer blade. The aluminum extrusion corresponds to the upstanding flange and provides support to securely attach the polymer blade. It takes several steps to manufacture a polymer blade with an internal aluminum extrusion including cutting, preparing surfaces and bonding agents. It is a time consuming method. Blades that wear out are typically thrown away and disposing of a blade consisting of polymer and metal combined is more expensive as they are not readily recycled or re-used. 
   Several manufacturers provide belt cleaners that have cleaning blades that have no internal metal which attach to the mainframe by means of using internally molded “pockets” which slide over upstanding weldments on the mainframe. One of these cleaners is manufactured by Martin Engineering under U.S. Pat. No. 4,598,823. These belt cleaning systems facilitate easy maintenance but have the disadvantage of not being able to utilize a large percentage of the wear media as a large portion of the blade is used to mount it to the weldments. Sometimes a larger portion of material is thrown away than is used to clean the belt, costing money. Another disadvantage of mounting a blade onto upstanding weldments is that the weldments are prone to damage from contact with the belt on the head pulley, or sometimes the cleaner gets pulled through by the belt because of a bad splice or other defect and the weldments are bent. Manufacturing a belt cleaning system consisting of a mainframe with weldments also costs more in materials and labor. As material handling operations around the world continually try to reduce maintenance and operational costs associated with conveyor belt cleaners, there is a need for a belt cleaner assembly that is simple to maintain, cheaper to manufacture, utilizes more of the cleaner blade and is less expensive to dispose of and recycle. 
   SUMMARY OF THE INVENTION 
   The conveyor belt cleaner in accordance with the present invention includes a mounting bar comprising a length of steel tubing of rectangular cross-section that is sufficiently long to span the width of the conveyor to be cleaned. Formed through one of the sides of the rectangular tube mounting bar are a series of regularly spaced T-slots where the head of the T comprises a square opening of a first dimension and the stem of the T is rectangular and of a width less than the square head. This stem is, of course, contiguous with the head and centered relative to it. 
   Completing the assembly are one or more wiper members, each formed from a tough elastomeric material, such as rubber or polyurethane, and including a base portion and an integrally formed arcuate wiper portion having a somewhat tapered cross-section and terminating in a beveled top edge surface. The underside of the base portion forms a channel having relatively short opposed parallel side edges and generally centered between the outwardly projecting side edges are a series of regularly space lugs appearing as a square in a plan view but T-shaped in an end view. The size of the square lugs projecting from the base of the wiper member is such that they readily fit through the square heads of the T-slots formed in the mounting tube, and they are spaced to conform with the spacing between adjacent heads of the T-shaped slots in the mounting tube member. 
   Being T-shaped in an end view, once the square lugs are inserted through the heads of the T-slots and a longitudinal force is applied to the wiper member, the lugs move into the stem portion of the T-slots. Because the heads of the lugs are wider than the stems of the lugs, the wiper member becomes locked into place. 
   The width of the channel formed in the base of the elastomeric wiper member is only slightly greater than the width dimension of the mounting tube and the opposed side edges of the mounting tube are thus straddled by the outwardly extending side edges defining the channel in the base of the wiper member. The square mounting tube is bolted or otherwise affixed to the frame of the conveyor closely adjacent to the conveyor&#39;s nose roller and with the beveled top edge of the wiper member in rubbing contact with the conveyor belt. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows the belt cleaner of the present invention installed to conveyor near head pulley; 
       FIG. 2  shows side cut a way view of the wiper blade and its mounting tube; 
       FIG. 3  is a view with the parts partially disassembled; and 
       FIG. 4  shows the end view of the present improved invention compared to two other state of the art, widely used belt cleaners. 
       FIG. 5  shows an alternative stub shaft and mounting bar. 
       FIG. 6  shows a rubber wedge plug on the mounting bar. 
       FIG. 7  shows a channel having slots for the wiper member lugs. 
       FIG. 8  shows a mounting bar having provision for mounting two sets of wiper blades. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import. 
   Referring first to  FIG. 1 , there is indicated generally by numeral  10  a conveyor having a frame  12  supporting bearing blocks on opposed sides thereof and journaled for rotation in the bearing blocks is a nose roller  16  about which is wrapped a conveyor belt  18 . Positioned closely adjacent the periphery of the nose roller  16  is the belt cleaning assembly comprising an embodiment of the present invention. 
   The cleaning assembly is indicated generally by numeral  20  and is seen to include a mounting bar  22  of generally rectangular (square) cross-section that spans the width of the nose roller  16  and is secured at opposed ends to the frame  12  by mounting plates  23  with a collar  21  and set screw  25  that permit the mounting bar  22  to be rotated and locked when adjustment of the belt cleaning assembly  20  is required as best seen in  FIG. 3 . Removably attached to the mounting bar  22  are replaceable wiper members, as at  24  and  26 , that are preferably molded or extruded from a synthetic rubber or a urethane elastomer especially formulated to resist wear in its rubbing contact with the exposed surface of the conveyor belt  18 . 
   To provide improved wiping action, the top edges  28  of the wipers  24  and  26  are preferably beveled to thereby define a leading edge  30 ,  38  that engages the belt  18  as it rubs past the cleaning members. As wear occurs, spring  51  rotates cylindrical stub shaft  52  to keep the wiper  24 ,  26  against the conveyor belt  80 . The mounting bar  22  can be unlocked, rotated and relocked to reestablish rubbing contracts between the belt  18  and wipers  24 ,  26 . 
   Referring next to  FIG. 2 , there is shown a view of the top surface  40  of the mounting bar  22  and a lower surface of the wiper  24 . It will be seen in  FIG. 3  that the elastomeric wiper member  24  has a base portion  32  and a curved or arcuate profile that is concave along surface  34  and convex along surface  36 . The wiper member  24  also tapers in thickness in progressing from the base portion  32  to the beveled top edge  28 . Thus, the wiper becomes slightly more flexible proximate its upper end when viewed in  FIG. 1  than it is proximate the base. 
   Integrally formed with the wiper member  24  and projecting from the underside of the base  32  are a plurality of lugs  70  that are somewhat T-shaped with a head  77  and a stem  78  as best seen in  FIG. 2 . The lugs  70  have a space  72  between the base portion  32  and the ridge  76  to allow the lug to engage the stem portion  46  of T-slot  42 . 
   The top surface  40  of the mounting bar  22  includes a plurality of T-slots  42  which are stamped or otherwise formed therethrough. The head portion  44  of the T-slot  42  is generally rectangular and of a predetermined width dimension. The stem portion  46  of the T-slot  42  is somewhat narrower than the predetermined width dimension of the head portion  44  and the stem  46  is generally centered with respect to the head portion  44 . 
   The lugs  70  projecting from the underside of the wiper blade  24  have heads  77  sized to fit through the head portion  44  of T-slots  42 . When the wiper blade  24  is moved to the right in  FIG. 3 , the stem portion  78  of lug  70  fits into the stem portion  46  of T-slot  42  with the ridge  76  engaging the stem  46  of T-slot  42  to prevent removal for the lug  70  from the mounting bar  22 . Space  72  between the ridge  76  and the base of the wiper blade  24  is on the order of the thickness of the mounting bar  22  material to insure a snug fit. 
   Referring once again to  FIG. 1 , when the mounting bar  22  is affixed to the frame  12  proximate the nose roller  16 , the concave surface  34  of the wiper members  24 ,  26  accommodates the curvature of the conveyor belt  18  as it rounds the nose roller  16  such that only the upper edge portions  30 ,  38  of the wiper members  24  and  26  are in rubbing contact with the outer surface of the belt  18  to thereby scrape away debris that might otherwise adhere to the belt. Periodically, as the contacting edge of the wiper members become worn, an operator need only loosen the set screw  25  that are shown as extending through a collar  21  that surrounds a cylindrical stub shaft  52  affixed to the opposed ends of the mounting bar  22  and that extends through the frame  12 . The stub shaft  52  can now be torqued to rotate the mounting bar  22  to bring the wipers back into contact with the surface of the conveyor belt  18 . The set screws  25  are then retightened. This adjustment step can be carried out, as needed, until such time as the wipers  24  and  26  are worn to the point that they require replacement. Replacement is easily effected by simply moving the wiper members laterally along the mounting bar until the lugs  70  become realigned with the head portion  44  of the T-slots  42  and then the wipers can then be lifted off from the mounting bar  22  and replaced with an unworn set. 
     FIG. 4  is an end view of the present invention on the right and two prior art belt cleaners to its left. Some of the advantages inherent in the present invention include the fact that a greater portion of the wiper member is an elastomer used for cleaning of the belt and less needs to be thrown away when contrasted with the prior art having embedded metal. Because no metal needs to be molded into the blade of the present invention to achieve mounting, the resulting wiper is less expensive than known prior art arrangements. Further, the wiper members can be changed without the need for tools of any type. The mounting system can be used with primary, secondary or under belt cleaners. A further advantage is that adjustment of the wiping pressure of the wiper member against the conveyor belt is easily achieved in a matter of only a few minutes as has been described above. 
   The embodiment shown in  FIG. 3  only contemplates placement of a single wiper member on one surface  40  of the mounting bar  22  ′. As shown in  FIG. 8 , it is also contemplated that T-slots, like T-slots  42 , can be provided on two or more sides of the mounting bar  22 ′ so that when one set of wiper members becomes worn down, an operator need only rotate the bar  22 ′ in the locking collars  21  on opposed sides of the frame  12  to bring a fresh wiper member up and into engagement with the conveyor belt  18  as it travels about the nose roller  16 . 
   Summarizing the advantages of the present invention, with no internal metal in the design of the blade, it is less costly to produce and to dispose of, as many governmental agencies now require, separating of polymer from metals and proper disposal of materials for recycling. 
   With the mounting method of the present invention using lugs  70  inserted through T-slots  42  in a mounting bar  22 , more of the wiper members  24 ,  26  are used for cleaning the conveyor belt  18  and less is thrown away after the wear limit is achieved. Only a small portion of the wiper members and some lugs are disposed of. 
   Long length blades can be manufactured and easily cut to length so one size wiper can be inventoried to reduce cost if necessary. 
   The manufacturing cost of the belt cleaner is greatly reduced by eliminating the weldments on the mounting tube required by the prior art designs. 
   If bracing  60  or strengthening of mounting tube is needed for a longer length belt cleaner application, it can be strengthened internally as shown in  FIG. 4  because of the ability to weld an angle or piece of metal internally, reducing the “footprint” of the tube. This is advantageous in allowing a smaller volume to ship, and the tube can be installed closer to the head pulley and still not have any external weldments interfere with the conveyor surface in the possibility of blade “pull through” from a conveyor splice or flaw grabbing the cleaner. Alternatively the bracing  60  could be on the outside of mounting bar  22 . 
   With the present invention, cylindrical stub shaft  52  mounting ends can be easily “internally mounted” as shown so there are no lock nuts or pins outside of the mounting tube. This reduces shipping cost, chance of lock nut or fastener damage, and makes the whole cleaner assembly more compact for installation in tight areas. 
   Alternatively as shown in  FIG. 5  a cylindrical stub shaft  152  with rectangular plates  120  can have an open portion of the shaft exposing set screw or bolt  125  for threading into nut  126  attached to stub shaft  152 . The bolt extends through an aperture in the stub shaft  152  to engage mounting bar  22  and can be tightened by a socket or other tool through slot  42  which provides an opening in the mounting bar for tightening the bolt  125  for fixing the stub shaft in a desired position in mounting bar  22 . In this manner the bolt  125  is inside of the mounting bar  22  and protected from damage, debris or corrosion making it easier to remove for maintenance. 
   With the present invention, securing the cleaning blade can be achieved by a retainer pin  55  held in place by wire  53  as seen in  FIG. 1 . The pin  55  adjacent a lug  70  blocks the lug  70  from moving in the T-slot  42 . If internally mounted reinforcement is used as in  FIG. 4 , apertures can be used on two opposed sides of the mounting bar  22  for a double bladed cleaner that can be simply rotated 180 degrees when one blade is worn out to bring the other into play. 
   With the present invention, securing the cleaning blade can be achieved by a retainer wire  53  as seen in  FIG. 1  or rubber plug/retainer or wedge plug  65  as shown in  FIG. 6  can be inserted in the open portion of the head  44  of slot  42  in the mounting bar  22  to prevent debris form entering the interior of the mounting bar  22  and may also be used to prevent the wiper member  24  from sliding out of position in the slots  42  particularly if pin  55  is not used. If pin  55  is used with retainer wire  53  the retainer wire can hold the wedge plug  65  in place. 
   Alternatively, instead of the mounting bar  22  being a rectangular tube it could be a channel  122  with slots  42  as shown in  FIG. 7 . 
   If desired, the narrowed portion of the conveyor belt cleaner lugs can be manufactured of a softer or more elastic material and the narrow portion of the lugs would stretch and could be used as a tensioning device. 
   With the present invention, installation and removal is greatly simplified as there is no metal to corrode or seize up, as with other prior art cleaners where the aluminum and dissimilar metals sometimes corrode and jam up.