Patent Publication Number: US-2010126832-A1

Title: Reinforced cleaning blade and method of manufacturing thereof

Description:
FIELD OF THE INVENTION 
     The invention relates to cleaning blades for conveyor belts and, more particularly, to reinforcement inserts for cleaning blades and methods of manufacturing reinforced cleaning blades. 
     BACKGROUND OF THE INVENTION 
     Cleaning blades for conveyor belts are known that are mounted to elongate support members or poles extending under or adjacent a conveyor belt with the tip of the blade engaged with the belt for scraping material therefrom. Certain cleaners are specifically designed for engaging the conveyor belt as it travels about the head pulley and are called primary cleaners versus those secondary cleaners that engage under the conveyor belt during its return run. In many of these primary cleaner systems, the cleaning blade is mounted to an upstanding flange attached to the support pole adjacent to the head pulley such as shown in the applicant&#39;s assignee&#39;s U.S. Design Pat. No. D482,508. 
     The blade bodies of primary cleaners such as of that in the &#39;508 patent extend along the width of the conveyor belt and have a curved configuration for engaging the belt at a tip end portion thereof. The base portion of the blade body at the lower end is typically thicker or wider for providing additional support where the blade is mounted to the support pole. In addition, as shown in the &#39;508 patent, an extruded support member or insert can be provided in the base portion at the slot opening thereof. As shown in  FIG. 6 , this aluminum insert is provided with a convex configuration including a number of projections and sharp corners to provide a secure connection between the blade body and the insert, particularly during use when exposed to scraping and impact forces. However, this complexly configured aluminum insert has an undesirably high cost associated with the extrusion manufacturer thereof. Accordingly, there is a need for an insert for cleaning blade bodies that can be manufactured economically. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a reinforced conveyor belt cleaning blade is provided including a blade body and a metal insert that is of a substantially constant cross-sectional configuration extending between ends thereof. The ends are surrounded by the molded material of the blade body so that the blade body and insert have a secure connection therebetween. The preferred insert is a formed or bent sheet metal member. The formed sheet metal member is very economical to a manufacturer. In addition, the preferred insert has smooth surfaces extending along its length without projections or sharp corners such as extruded into the prior, more costly aluminum insert. 
     In another aspect, a method of manufacturing a conveyor belt cleaning blade is provided including placing a metallic insert for the cleaning blade in a mold and molding the body of the cleaning blade with polymeric material extending completely around ends of the metallic insert. 
     In one form, the metallic insert is magnetically held at a predetermined position in the mold. Preferably, the insert is magnetically held by supporting the insert on a rail on which magnets are mounted. 
     In another form, the method includes bending the insert to a predetermined configuration prior to placing the insert in the mold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a cleaning blade showing a blade body having an insert molded therein; 
         FIG. 2  is an elevational view of the cleaning blade of  FIG. 1  showing a faceted surface thereof. 
         FIG. 3  is an enlarged elevational view of the insert showing an upper flat portion and depending leg portion thereof; 
         FIG. 4  is a plan view of a mold rail for use in the mold for forming the blade of  FIG. 1 ; 
         FIG. 5  is an enlarged flat, fragmentary elevational view of the rail of  FIG. 4  showing magnets fixed thereto; and 
         FIG. 6  is a cross-sectional view of a prior cleaning blade including an extruded aluminum insert. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIGS. 1 and 2 , a cleaning blade  10  having a body  12  of polymeric material and an insert  14  of metallic material is shown. The cleaning blade body  12  has a configuration similar to the configuration of prior cleaning blade  16  shown in  FIG. 6  provided by applicant&#39;s assignee herein. The main differences reside in the respective base portions  18  and  20  thereof and, more particularly, with respect to the respective metallic inserts  14  and  22  thereof. 
     In this regard, the blade body  12  has an upper tip end portion  24  that is curved for engaging the conveyor belt as it extends around the head pulley such as when the blade  10  is used as a primary cleaner. As can be seen in  FIG. 2 , the blade has a facetted outer surface including a series of flat surface portions  26  with corners or sharp break lines  28  formed therebetween. The inner surface  30  of the blade body  12  that faces the head pulley and belt traveling thereabout has a similar faceted configuration. Other configurations for the corresponding inner and outer surfaces  26  and  30  could be provided. The lower base portion  18  has a slightly greater width than the remainder of the blade body  12  and has the insert  14  embedded therein such as during the molding process, as will be described hereinafter. 
     The base portion  18  has depending leg portions  32  and  34  spaced to form a open ended slot opening  36  therebetween. As is known, the slot  36  opens downwardly and is adapted to receive an upstanding plate or flange attached or welded to the support pole extending along and adjacent to the head pulley, for instance. The blade body  12  is also provided with a series of laterally extending throughbores  38  for receiving mounting pins or bolts that affix the cleaning blade to the upstanding flange of the support pole. 
     To provide the blade  10  with sufficient stiffness, particularly at the base portion  18  thereof where it is mounted to the support pole, a metallic insert  14  is provided, as shown in  FIGS. 1 and 3 . The present insert  14  is of low cost construction and provides manufacturing efficiencies over the manufacturer of the prior blade body  16  along with its extruded aluminum insert  22 . In this regard, the insert  14  has a fairly simple construction being of substantially constant cross-sectional thickness extending between ends  40  and  42  thereof. The low cost insert  14  is molded in the blade body  12  so that the ends  40  and  42  are disposed within and surrounded by the molded material of the base body  12 . The molded material is a polymeric material such as polyurethane. 
     Rather than an extrusion similar to insert  22  having various rib projections  44  and sharp angled corners  46  along its surfaces, the insert  14  extends lengthwise in the blade body  12  and has substantially smooth upper and lower surfaces  46  and  48  extending along its length so that ribs  44  and corners  46  such as in the extruded prior insert  22  are avoided. Instead of relying on projections  44  and sharp corners  46  to provide increased bonding area between the urethane of the blade body  16  and the extruded insert  22 , the insert  14  has both of the ends  40  and  42  embedded completely within the blade body  12 , and specifically the leg portions  32  and  34  thereof. In this regard, the preferred insert  14  has a generally inverted U-shape configuration. As illustrated, the insert  14  has an upper flat portion  50  and depending side leg portions  52  and  54  that extend from the upper portion  50  to the insert ends  40  and  42 . The upper flat portion  50  extends in the base portion  44  across the upper end of the slot opening  36 . The leg portions  52  and  54  extend in the corresponding leg portions  32  and  34  of the blade body base portion  34 . With the insert ends  40  and  42  completely surrounded by molded polymeric material, there is molded material below the leg ends  40  and  42 , as can be seen in  FIG. 1 . In addition, the insert legs  52  and  54  are completely embedded and surrounded by molded polymeric material in the corresponding leg portions  32  and  34 . Accordingly, while there is a sacrifice in the resistance to sheer forces at the interface of the smooth surfaces  46  and  48  of the insert and the molded material of the blade body  12  versus the ribbed and sharply contoured extruded insert  42 , the provision of the leg ends  40  and  42  completely embedded in the blade body  12  with molded material below the leg ends  40  and  42  provides the insert  14  with a secure connection to the blade body  12  and resistance to separation therefrom during scraping operations with the cleaning blade  10  herein. 
     The preferred and illustrated insert  14  is a bent or formed sheet metal member such as of a steel material. As mentioned, there is a substantially constant thickness between the upper and lower surfaces  46  and  48  as they extend along the upper flat portion  50  and the leg portions  52  and  54  of the elongate insert  14 . The leg portions  52  and  54  are bent from the upper portion  50  so that there are radiused or curved transitions along the surfaces  46  and  48  between the upper portion  50  and the leg portions  52  and  54 . As can be seen in  FIG. 3 , the legs  52  and  54  extend downwardly from the upper portion  50  and taper away from each other to the ends  40  and  42 . The sheet metal can be approximately 7 gage or approximately 0.18 inch in thickness between the surfaces  46  and  48  thereof. 
     To form the blade body with the insert  14  therein, the insert  14  is molded in situ with the blade body  12 . In this regard, the insert  14  is placed in the mold for forming the cleaning blade body  12  and the body  12  is molded about the insert  14  such that the ends  40  and  42  are completely surrounded by the polymeric material of the cleaning blade body  12 . The insert  14  is first formed to the generally inverted U-shaped configuration by bending the sheet steel member so that the leg portions  52  and  54  depend from the upper flat portion  50 , as shown in  FIG. 3 . For securely holding the steel insert  14  in the mold, an elongate support rail  56  is provided, as shown in  FIGS. 4 and 5 . The support rail  56  has several magnets  58  mounted along its length so that the insert  14  is magnetically held to the rail  56 . 
     More specifically, the elongate insert  14  is placed into the mold so that the flat upper portion  50  extends along and rests on the rail  56  with the leg portions  52  and  54  extending downwardly in the mold from the rail  56  along either side thereof. For locating the insert  14  on the rail  56 , locating pins and openings can be used on the rail and the insert  14 . With the insert  14  properly located on the rail  56 , the magnets  58  will draw the lower surface  58  at the insert flat portion  50  down into tightly held engagement with the rail  56 . The legs  52  and  54  will extend downwardly from either side of the rail  56  with their ends  40  and  42  positioned in the mold so that when the blade body is molded, molded material of the blade body leg portions  32  and  34  will extend below the insert leg ends  40  and  42 , as previously has been described. 
     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.