Patent Publication Number: US-10758915-B2

Title: Material reduction system and processing tools for a material processing machine

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. No. 62/233,392, filed on Sep. 27, 2015, the contents of which are hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     A variety of machines have been developed to recycle, reduce, or otherwise process materials such as trees, brush, and other vegetation. The processing machines chip, cut, grind, shred, pulverize or otherwise reduce the material. Exemplary material processing machines include chippers, grinders, shredders, hammer mills, forestry mulchers, and the like. 
     Forestry mulching is a land clearing method of particular interest and development. The forestry mulcher, also referred to as a masticator or brushcutter, typically comprises a hydraulically-powered mulching attachment removably coupled to a tractor or other implement. The mulching attachment typically comprises a rotary drum equipped with processing tools disposed about the drum. The processing tools reduce the material as the implement forcibly urges the rotating processing tools into direct contact with the material sought to be reduced. Given the operating conditions associated with forestry mulching and similar operations, those having skill in the art readily appreciate the marked mechanical stress and wear endured by many of the components of the processing machine. 
     Due to these demands of forestry mulching and similar operations, the processing tools typically comprise a replaceable tool head—often called a “wear part”—removably coupled to a tool holder fixedly secured to the rotary drum. The tool head is positioned in an operating direction typically the rotational direction of the rotary drum. Relative to the tool holder and rotary drum, the time and expense associated with repair and/or replacement of the tool heads are appreciably less. Thus, during operation of the processing machine, it is desirable to concentrate contact between the material and the tool head, thereby focusing wear on the tool head and limiting wear on the tool holder and rotary drum. 
     Known systems, however, do not adequately limit contact between the material and the tool holder and rotary drum. As the rotary drum rotates in the operating direction, the material undesirably contacts the rotary drum prior to the tool head or after engagement with the tool head. Often, the material also undesirably contacts the tool holder prior to the tool head. In addition to the stress and wear endured by the drum and the tool holder, suboptimal cutting depth to suitably reduce the material often results. 
     Likewise, subsequent to the material “passing” each of the tool heads, known systems do not adequately limit wear to the tool holder adjacent the cutting head opposite the operating direction. In addition to the wear endured by the tool holder, the result often prevents the known systems from using relatively simpler means of connection between the tool head and the tool holder. 
     Therefore, a processing tool system for a material processing machine designed to overcome one or more of the aforementioned disadvantages is desired. 
     SUMMARY OF THE DISCLOSURE 
     According to an exemplary embodiment of the present disclosure, a material reduction system comprises a rotary drum rotatable about a longitudinal axis in an operating direction. The rotary drum has an outer surface spaced from the longitudinal axis by a radius of curvature. A tool holder comprises a base portion fixedly mounted to the outer surface of the rotary drum, and a tool mounting portion extending upwardly from the base portion. The base portion has a leading member extending in the operating direction. The leading member defines a raker surface oriented away from the operating direction at a first predefined angle. The material reduction system further comprises a processing tool having a tool body abutting the tool mounting portion and removably coupled to the tool holder. A reducing member is coupled to the tool body. The reducing member defines a leading face oriented toward the processing direction at a second predefined angle. The first and second predefined angles are such that material is directed into contact with the reducing member to limit contact with the tool body and the tool mounting portion during operation of the material reduction system. 
     According to another exemplary embodiment of the present disclosure, a material reduction system comprises a rotary drum rotatable about a longitudinal axis in an operating direction. The rotary drum has an outer surface spaced from the longitudinal axis by a radius of curvature. A tool holder comprises a base portion fixedly mounted to the outer surface of the rotary drum. The base portion comprises a leading member extending in the operating direction and a trailing member extending in an opposite direction from the leading member. The tool holder further comprises a tool mounting portion extending upwardly from the base portion. The tool mounting portion has a forward surface facing the operating direction, a rearward surface facing an opposite direction from the forward surface, and an upper surface between the forward and rearward surfaces. A processing tool is removably coupled to the tool holder. The processing tool has a tool body directly abutting the forward surface of the tool mounting portion. The process tool has an upper flange directly abutting at least a portion of the upper surface of the tool mounting portion to direct material away from the upper and rearward surfaces of the tool mounting portion during operation of the material reduction system. 
     According to another exemplary embodiment of the present disclosure, a processing tool is configured to be removably coupled to a tool holder of a material reduction system with the tool holder having a projection. The processing tool comprising a top surface, a bottom surface opposite said top surface, and opposing sides separated by said top and bottom surfaces. A leading face of the processing tool faces an operating direction. A tool mounting surface of the processing tool is opposite said leading face for directly abutting at least a portion of the tool holder. The tool mounting surface comprises an upper flange and a lower flange for receiving the projection from the tool holder to prevent rotation of said processing tool relative to the tool holder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of the present disclosure will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a material processing machine comprising a material reduction system in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 2  is a perspective view of the material reduction system of  FIG. 1 ; 
         FIG. 3  is a fragmented perspective view of the material reduction system of  FIGS. 1 and 2 ; 
         FIG. 4  is a perspective view of a processing tool system in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 5  is a side elevation view of the processing tool system of  FIG. 4 ; 
         FIG. 6A  is a side elevation view of the processing tool system of  FIG. 4  mounted on a schematic representation of a rotary drum; 
         FIG. 6B  is a side elevation view of a processing tool system in accordance with another exemplary aspect of the present disclosure mounted on a schematic representation of a rotary drum; 
         FIG. 7  is a side elevation view of the processing tool system of  FIG. 4  positioned in operational engagement with a schematic representation of vegetation; 
         FIG. 8  is a perspective view of the processing tool system of  FIG. 6B ; 
         FIG. 9  is a side elevation view of the processing tool system of  FIG. 6B ; 
         FIG. 10  is a side elevation view of the processing tool system of  FIG. 4  with a schematic representation of an exemplary material path during operation of the material reducing operation; 
         FIG. 11  is a top plan view of the processing tool system of  FIG. 4 ; 
         FIG. 12  is an exploded assembly view of the processing tool system of  FIG. 8 ; 
         FIG. 13  is a perspective view of a tool holder of the processing tool system of  FIG. 4 ; 
         FIG. 14  is a side elevation view of the tool holder of  FIG. 13 ; 
         FIG. 15  is a perspective view of a tool body of the processing tool system of  FIG. 4 ; 
         FIG. 16  is a side elevation view of the tool body of  FIG. 15 ; 
         FIG. 17  is a perspective view of a processing tool of the processing tool system of  FIG. 4  with processing features in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 18  is a perspective view of a processing tool with processing features in accordance with another exemplary embodiment of the present disclosure; and 
         FIG. 19  is a perspective view of a processing tool with processing features in accordance with another exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary material processing machine  30  comprising a material reduction system  34  coupled to an implement  36 . The implement  36  may comprise a multi-purpose vehicle configured to be removably coupled to a variety of powered material reduction operations. The illustrated embodiment comprises a forestry mulcher coupled to the implement  36  comprising a two-tracked vehicle configured to be driven by an operator situated in a cabin. During operation, the implement  36  forcibly urges the material reduction system  34  into direct contact with the material to reduce stumps, trees, brush, and vegetation, and the like. The implement  36  may be powered by an internal combustion engine having 100, 200, 400 or more horsepower. In addition to a forestry mulcher, the present disclosure contemplates that the material reduction system  34  disclosed herein may be implemented into any number of operational contexts, including shredders, chippers, grinders, crushers, and the like. The present disclosure further contemplates that the material reduction system  34  may be incorporated into a generally non-movable implement as opposed to being coupled to a drivable implement  36 . In such an alternative embodiment, the material sought to be reduced may be transported to and fed into the generally stationary apparatus, after which the advantages of the material reduction system  34  described herein are similarly realized. 
     With continued reference to  FIG. 1 , attachment means  38  removably couple the material reduction system  34  and the implement  36 . The attachment means  38  may take on any known or conventional design. In one example, the attachment means  38  comprise generally U-shaped forks configured to couple with one or more elongated transverse members. The material reduction system  34  is preferably hydraulically powered through means commonly known in the art. The material reduction system  34  and/or the implement  36  may comprise fluid sources, pumps, valves, fluid lines, and other components required to hydraulically operate the material reduction system  34 . 
     The material reduction system  34  in accordance with an exemplary embodiment of the present disclosure is illustrated in  FIGS. 2 and 3 . The material reduction system  34  comprises a rotary drum  40 . Referring to  FIGS. 2 and 3 , the rotary drum  40  is tubular or cylindrical in shape and comprises opposing ends. The rotary drum  40  is rotatable about a longitudinal axis L extending between the opposing ends. The rotary drum  40  further comprises an outer surface  42  spaced apart from the longitudinal axis L by a radius of curvature R as shown in  FIG. 3 . In other words, the distance between the outer surface  42  and the longitudinal axis L defines a radius of curvature R of the rotary drum  40 . Other suitable shapes of the rotary drum are contemplated such as a hexagon, octagon, decagon, and the like. 
     The rotary drum  40  is operably coupled to or otherwise integral with a shaft  44  extending coaxially through the rotary drum  40 , as illustrated in  FIG. 2 . The shaft  44  has opposing ends operably coupled to drive means (not shown) associated with the material reduction system  34 . Via the drive means or otherwise, the rotary drum  40  is configured to rotate about the longitudinal axis L in an operating direction OD. The perspective view of  FIG. 2  shows the operating direction OD in a counterclockwise direction. 
     The material reduction system  34  comprises one or more processing tool systems  46 .  FIGS. 2 and 3  illustrate a plurality of processing tool systems  46  operably coupled to the rotary drum  40 . More specifically, the processing tool systems  46  are operably coupled to the outer surface  42  of the rotary drum  40 . The processing tool systems  46  may be arranged on the outer surface  42  in any number of desired configurations. For example, the illustrated embodiment shows the processing tool systems  46  arranged in a generally spiral configuration between the opposing ends of the rotary drum  40 . Among other advantages, the spiral configuration may optimize “coverage” of the processing tool systems  46  about the rotary drum  40  to limit abrasion of the material on the rotary drum  40  and promote a smoother, shaving-style cutting operation. Further, the spiral configuration may urge the reduced material towards a center (i.e., generally midway between the opposing ends) of the rotary drum  40 , which concentrates the processed material. Directing the reduced material towards the center improves mulching operations and prevents debris from encroaching on the bearings of the shaft  44 . The processing tool systems  46  may be arranged in any advantageous manner based on the application or otherwise. 
       FIGS. 4, 5 and 6A  show an exemplary processing tool system  46 . The processing tool system  46  comprises a tool holder  48  configured to be fixedly mounted on the outer surface  42  of the rotary drum  40 . Preferably, the tool holder  48  is welded to the outer surface  42  of the rotary drum  40 , as described in detail below, but other joining means are contemplated. 
     The tool holder  48  may comprise a main body  50 . With reference to  FIG. 5 , the tool holder  48  comprises a base portion  52  and a tool mounting portion  54 . Each of the base portion  52  and the tool mounting portion  54  may be unitary or monolithic and comprise the main body  50 . Alternatively, the base portion  52  and the tool mounting portion  54  may be discrete structures operably coupled to one another to comprise the main body  50 . As illustrated in  FIG. 5 , the tool mounting portion  54  is positioned superiorly to the base portion  52 . In other words, the tool mounting portion  54  extends upwardly from the base portion  52 . 
     In an exemplary embodiment, the base portion  52  is generally C-shaped and comprises an arcuate drum mounting surface  60  having a radius of curvature R′ substantially equal to the radius of curvature R of the rotary drum  40 . The radius of curvature R′ of the drum mounting surface  60  may be relative to the longitudinal axis L of the rotary drum  40  (see  FIG. 6A ). The drum mounting surface  60  is fixedly mounted to the outer surface  42  of the rotary drum  40 , as best shown in  FIG. 3 . As described below, the drum mounting surface  60  is preferably welded to the outer surface  42  of the rotary drum  40 . 
     The base portion  52  may further comprise a leading member  56  and a trailing member  58 . The leading member  56  extends in the operating direction OD, whereas the trailing member  58  extends in an opposite direction of the leading member  56  or away from the operating direction OD. In other words, the leading member  56  and the trailing member  58  are positioned opposite a central portion  57  of the base portion  52 . Each of the base portion  52 , the leading member  56 , and the trailing member  58  may be unitary or monolithic. Alternatively, one or more of the leading member  56  and the trailing member  58  may be discrete structures operably coupled to the central portion  57  to comprise the base portion  52 . In an exemplary embodiment, each of the leading member  56  and the trailing member  58  is an arm or a wing-like structure of the base portion  52 . Each of the leading member  56  and the trailing member  58  may comprise a portion of the drum mounting surface  60  such that the drum mounting surface  60  comprises a smooth arc along substantially an entirety of the base portion  52 . Among other advantages disclosed herein, the leading member  56  and the trailing member  58  provide wider contact points between the drum mounting surface  60  and the outer surface  42  of the rotary drum  40 , which is desirable based on the demands of the material reduction system  34 . 
     The material reduction system  34 , and more specifically the processing tool system  46 , comprises a processing tool  64  removably coupled to the tool holder  48 . The processing tool  64  comprises a tool body  66  and a reducing member  68  coupled to the tool body  66 . The reducing member  68  is the component of the material reduction system  34  that typically reduces the material during operation of the material processing machine  30 . In other words, the reducing member  68  is fabricated from suitable material and in a suitable shape so as to chip, cut, grind, shred, pulverize or otherwise reduce the material. Those having skill in the art readily appreciate the reducing member  68  is typically fabricated, at least in part, from carbide to meet the demands of the application; however other sufficiently hard and/or hardened materials are contemplated.  FIG. 4  illustrates one exemplary embodiment of the reducing member  68  comprising two processing teeth  70   a  arranged in a side-by-side configuration. Other exemplary reducing members  68  are described in detail below. 
     With continued reference to  FIGS. 4, 5 and 6A , the processing tool  64  is removably coupled to the tool holder  48 , and more particularly to the tool mounting portion  54  of the main body  50  of the tool holder  48 . A fastener  73  couples the processing tool  64  and the tool mounting portion  54 . To that end, a borehole  75  extends through the tool mounting portion  54  of the tool holder  48 . The borehole  75  is configured to receive the fastener  73 . Based on one or more features of the present disclosure, as described in detail below, the fastener  73  may comprise a singular standard Hex bolt commonly known in the art. 
     In the broadest sense, operation of the material processing machine  30  comprises rotating the rotary drum  40  of the material reduction system  34  in the operating direction OD. The processing tool systems  46  coupled to the rotary drum  40  are likewise rotated and forcibly urged into direct contact with the material sought to be reduced. The reducing member  68  of the processing tool  64  reduces the material as the processing tool system  46  sweeps by the material in the operating direction. Yet known systems do not adequately limit contact of the material with the tool holder and/or drum, thereby accelerating undesirable wearing of these components. It is an advantage of the present disclosure to direct, urge, or otherwise guide material into contact with the reducing member  68  to not only limit contact of the material with the tool body  68  (of the processing tool  64 ) and the tool mounting portion  54  (of the tool holder  48 ), but also improve the overall efficiency of the processing operation. 
     As mentioned, the base portion  52  comprises the leading member  54  extending in the operating direction OD, as illustrated in  FIG. 5 . The leading member  54  defines a raker surface  74  oriented away from the operating direction OD. With reference to  FIG. 5  showing a clockwise operating direction, “oriented away” comprises a negative slope when viewed in elevation. Stated differently, raker surface  74  being “oriented away” results in the material translating or moving across the raker surface  74  as the processing tool  46  rotates in the operating direction OD. 
     The raker surface  74  may be positioned in a manner to contact the material prior to the processing tool  64 . The raker surface  74  is configured to direct material into contact with the reducing member  68  of the processing tool  64 . To that end, the raker surface  74  is oriented away from the operating direction OD at a first predefined angle α 1 . In one exemplary embodiment illustrated in  FIG. 5 , the raker surface  74  is planar and aligned with at least a portion of the reducing member  68 . In such an embodiment, the first predefined angle α 1  may be such that the raker surface  74  is substantially collinear with at least a portion of the reducing member  68 . 
     Likewise, the reducing member  68  defines a leading face  72  oriented towards the operating direction OD. With continued reference to  FIG. 5 , the leading face  72  may further be defined by a portion of the tool body  66 . In other words, the leading face  72  may comprise a portion of the tool body  66  facing the operating direction OD, and a portion of the reducing member  68  facing the operating direction OD. More specifically, the reducing member  68  comprises a portion of the leading face  72  of the processing tool spaced apart from the base portion  52  of the tool holder  48  by a portion of the tool body  66 . The leading face  72  is oriented towards the operating direction OD at a second predefined angle α 2 . 
     The first and second predefined angles α 1  and α 2  are such that material is directed into contact with the raker surface  74  and the reducing member  68  to limit contact of the material with the tool body  66  and the tool mounting portion  54  during operating of the material reduction system  34 . In one exemplary embodiment illustrated in  FIG. 5 , the first and second predefined angles α 1  and α 2  may be relative to a line  76  separating the base portion  50  and the tool mounting portion  54  of the tool holder  48 . In such an embodiment, each of the first and second predefined angles α 1  and α 2  may be acute angles. In one example, the first predefined angle α 1  may be between 45 and 75 degrees, and the second predefined angle α 2  may be between 55 and 85 degrees. In another example, the first predefined angle α 1  may be between 55 and 65 degrees, and more particularly 58 degrees, and the second predefined angle α 2  may be between 65 and 75 degrees, and more particularly 72 degrees. In many respects, the first and second predefined angles α 1  and α 2  may be codependent. That is, the second predefined angle α 2  may be selected based, at least in part, on the first predefined angle α 1  such that material is directed into contact with the reducing member  68 . In one example, the leading face  72  of the processing tool  64  is angled relative to the raker surface  74 —the sum of first and second predefined angles α 1  and α 2 —at an angle between 120 and 140 degrees. 
     Referring now to  FIG. 6A , the first and second predefined angles α 1 ′ and α 2 ′ may be relative to a line  78  comprising the radius of curvature R of the rotary drum  40  extending through the reducing member  68  or other suitable structure on the processing tool system  46 .  FIG. 6A  shows a processing tool system  46  mounted on the rotary drum  40 . The line  78  extends from the longitudinal axis L of the rotary drum  40  to the reducing member  68  of the processing tool  64 . As shown in  FIG. 6A , the first predefined angle α 1 ′ is defined between the raker surface  74  and the line  78 , and the second predefined angle α 2 ′ is defined between the leading face  72  and the line  78 . In one example, the first predefined angle α 1 ′ may be between 35 and 55 degrees, and more particularly between 40 and 50 degrees, and the second predefined angle α 2 ′ may be between 1 and 15 degrees, and more particularly between 5 and 7 degrees. The present disclosure contemplates other methods for defining the first and second predefined angles α 1 , α 1 ′ and α 2 , α 2 ′ relative to a reference structure, line, or other feature not comprising the processing tool system  46  (e.g., a reference line tangent or normal to the outer surface  42  of the rotary drum, a horizontal reference line when the processing tool system  46  is positioned as illustrated in  FIG. 6 , etc.). 
     An exemplary operation of the material reducing system  34  of the present disclosure will now be described with reference to  FIG. 7 .  FIG. 7  shows a representation of vegetation V that may be encountered during a land clearing operation. The vegetation V may be a tree, stump, branch, brush, mulch, and the like. The vegetation V may be freely floating mulch, as illustrated, or the vegetation V may be rooted in the ground such as a tree stump. As the rotary drum  40  (not shown in  FIG. 7 ) rotates, the processing tools  46  rotate as well, one of which is illustrated in  FIG. 7  for simplicity. The processing tools  46  enter the cutting zone CZ, typically between 4 o&#39;clock and 6 o&#39;clock on the rotary drum  40  when viewed in elevation (see  FIG. 6 ). The processing tools  46  encounter the vegetation V. The leading member  72 , and more particularly the raker surface  74 , comes into contact with the vegetation V. If rooted, the vegetation V may deflect based, at least in part, on the first predefined angle α 1 , α 1 ′. If unrooted, the vegetative debris (e.g., the mulch) is deflected from the raker surface  74  at approximately the first predefined angle α 1 , α 1 ′. In either instance, the material is directed or otherwise guided generally towards the reducing member  68 . 
     Further, the leading face  72  is oriented towards the operating direction OD at the second predefined angle α 2 , α 2 ′. Together with the first predefined angle α 1 , α 1 ′, the second predefined angle α 2 , α 2 ′ directs or otherwise guides into contact with the reducing member  68  as opposed to the tool body  66  adjacent the reducing member  68 . If, for example, the leading face  72  was oriented towards the operating direction OD at less than a suitable second predefined angle α 2 , α 2 ′, the vegetation V may “miss” the reducing member  68 . Conversely, if the leading face  72  was oriented towards the operating direction OD at greater than a suitable second predefined angle α 2 , α 2 ′, the vegetation V may contact the tool body  66  adjacent the reducing member  68 , which is not typically designed to reduce the material. Therefore, in addition to limiting contact with the tool body  66  to minimize wear, the present disclosure may advantageously improve the land clearing operation by controlling the depth at which the reducing member  66  penetrates the material. 
     As mentioned, the first and second predefined angles α 1 , α 1 ′ and α 2 , α 2 ′ are such that material is directed into contact with the raker surface  74  and the reducing member  68 . Consequently, the material reduction system  34  may further comprise a hardened face  82  coupled to the raker surface  74 . The hardened face  82  is configured to provide additional durability to the tool holder  48 .  FIGS. 5, 7 and 14  illustrate an exemplary hardened face  82 . The hardened face  82  may be welded, brazed, or otherwise secured to the raker surface  74 . In one example, the hardened face  82  is carbide-embedded, but other suitable materials are contemplated. The hardened face  82  may be generally roughened as shown in  FIGS. 5 and 7 , or generally smooth as shown in  FIG. 14 . The present disclosure contemplates the hardened face  82  may be raised from the raker surface  74  as shown in the figures, or recessed within the raker surface  74 , after which the hardened face  82  creates a generally flush raker surface  74 . 
     Referring to  FIG. 5 , the leading member  56  may further define a second raker surface  84 . The second raker surface  84  is positioned between the raker surface  74  and the processing tool  64  when the processing tool  64  is coupled to the tool holder  48 . The second raker surface  84  may be continuous with first raker surface  74 , but oriented at a different angle than the raker surface  74 . More specifically, the second raker surface  84  is oriented away from the operating direction OD at a third predefined angle α 3 . The third predefined angle α 3  is preferably less than the first predefined angle α 1  such that the second raker surface  84  slopes away from the operating direction OD to a greater extent than the raker surface  74 . In one example, third predefined angle α 3  is between 15 and 30 degrees, and more approximately 23 degrees relative to the line  76  separating the base portion  52  and the tool mounting portion  54 . In another example and with reference to  FIG. 6 , the third predefined angle α 3 ′ is between 80 and 100 degrees. The raker surface  74  and the second raker surface  84  may be collectively referred to herein as a raker  86 . The second raker surface  84  is configured to direct material into contact with the reducing member  68  as the material moves from the raker surface  74  towards the leading face  72  of the processing tool  64 . 
     Referring to  FIGS. 6B, 8 and 9 , another exemplary embodiment of a tool processing system  46 ′ is illustrated. In many respects, the tool processing system  46 ′ is similar to the tool processing system  46  previously described. As well understood, the tool processing system  46 ,  46 ′ is coupled to the rotary drum  40 , and more particularly, the drum mounting surface  60  of the tool holder  48  is fixedly mounted to the outer surface  42  of the rotary drum  40 . Those having skill in the art readily appreciate the size the rotary drum  40  may vary based on any number of factors, including the size of the implement  36 , size and/or type of the material to be reduced, and the like. For example, implements  36  with over 200 horsepower may use a drum with a radius of curvature between 25 and 35 inches (e.g., diameter of 64 inches), whereas implements  36  with less than 200 horsepower may comprise a drum with a radius of curvature between 15 and 25 inches (e.g., diameter of 43 inches). Since the drum mounting surface  60  has a shape contoured to the rotary drum  40 , it readily follows that the radius of curvature R′ of the drum mounting surface  60  is dependent on the radius of curvature R of the rotary drum  40  (see  FIGS. 6A and 6B ). 
     The radius of curvature R′ of the drum mounting surface  60  may influence the shape of the leading member  56  and/or the trailing member  58 . For example,  FIGS. 6B and 9  illustrate an exemplary drum mounting surface  60  with a smaller radius of curvature R′ than the embodiment illustrated in  FIGS. 5 and 6A . Consequently, the leading member  56  and the trailing member  58  have differing characteristics than those previously described in the exemplary embodiment of  FIG. 5 . One differing characteristic includes the first and third predefined angles α 1 , α 1 ′ and α 3 , α 3 ′. Stated differently, the shape of the raker  86 , and more particularly the orientations of the raker surface  74  and the second raker surface  84  are different between the two exemplary embodiments. 
     Because the radius of curvature R′ of the drum mounting surface  60  is smaller in the exemplary embodiment of  FIGS. 6B and 9 , the first predefined angle α 1 , α 1 ′ is defined accordingly to direct material into contact with the reducing member  68  of the processing tool  64 . Particularly when referenced relative to the line  78  extending from the longitudinal axis L of the rotary drum  40  extending through the reducing member  68  (see  FIGS. 6A and 6B ), the first predefined angle α 1 , α 1 ′ is less than the similarly defined angle in the exemplary embodiment of  FIG. 5 . In other words, the raker surface  74  is steeper and/or of greater slope. Among other reasons, the steeper raker surface  74  directs the material more rapidly towards the reducing member  68  because the processing tool system  46  is in the cutting zone CZ for a shorter period of time, which is a function of the size of the rotary drum  40  (i.e., the portion of the outer surface  42  of the rotary drum  40  between the same angular positions is based on the radius of curvature R of the drum). Thus, the first predefined angle α 1 , α 1 ′ may be based, as least in part, on the radius of curvature R of the rotary drum  40 . 
     Likewise, the third predefined angle α 3 , α 3 ′ of the exemplary embodiment of  FIGS. 6B and 9  is defined accordingly to direct material into contact with the reducing member  68  as the material moves from the raker surface  74  towards the leading face  72  of the processing tool  64 . Particularly when referenced relative to the line  78  extending from the longitudinal axis L of the rotary drum  40  extending through the reducing member  68  (see  FIGS. 6A and 6B ), the third predefined angle α 3 , α 3 ′ is less than the similarly defined angle in the exemplary embodiment of  FIGS. 5 and 6A . In other words, the second raker surface  84  is shallower and/or of lesser slope based, at least in part, on the steeper orientation of the raker surface  74 . As such, the third predefined angle α 3 , α 3 ′ may be based, as least in part, on the radius of curvature R of the rotary drum  40 . 
     In an exemplary embodiment, the second predefined angle α 2 , α 2 ′ may not be based on the radius of curvature R of the rotary drum  40 . In such an embodiment, the leading face  72  of the processing tool  64  is “standardized” and configured to be coupled to tool holders  48  having raker surfaces  74  defining varied first predefined angles α 1 , α 1 ′. Based on the known characteristics the leading face  72  of the processing tool  64  (i.e., second predefined angle α 2 , α 2 ′ and distance from bottom surface of tool body  66  to reducing element), the raker  86  is designed accordingly and compensates for the radius of curvature R of the rotary drum  40 . Such an example may be particularly appropriate in the context of a catalogue of replaceable wear parts. 
     In another non-exhaustive example, the present disclosure also contemplates that the second predefined angle α 2 , α 2 ′ may be based, as least in part, on the radius of curvature R of the rotary drum  40 . The processing tools  64  may comprise a specific second predefined angle α 2 , α 2 ′ that is tailored for specific tool holders  48  and/or specific sizes or rotary drums  40 . “Pairing” components in such a manner may be particularly appropriate in applications that require increased control over depth in which the reducing member  68  engages the material. 
     As mentioned, the radius of curvature R′ of the drum mounting surface  60  may influence the shape of the trailing member  58 . In one exemplary embodiment, a length of the trailing member is based, at least in part, on said radius of curvature R of the rotary drum  40 . The length L TM  of the trailing member  58  may be defined as a horizontal distance from the rearward most point of the leading member  58  to a line extending from the rearward surface  90 . With reference to  FIGS. 5 and 9 , the trailing member  58  shown in  FIG. 9  has a length L TM  greater than the length L TM  of the trailing member  58  shown in  FIG. 5 .  FIGS. 6A and 6B  illustrate the processing tool systems  46 ,  46 ′ having trailing members  58  of different length and shape based on the radius of curvature R of the rotary drum  40 . Among other reasons, the increase in length is to compensate for a reduction in the radius of curvature R such that the center of gravity of the tool processing system  46  remains aligned with the longitudinal axis L. Those having skill in the art readily appreciate the need for the tool processing system  46  to be radially balanced on the rotary drum. 
     One of the many advantages of the present disclosure is to limit contact between the material and the tool holder (other than the material contacting the raker  86  preferably coupled with the hardened face  82 ). Referring to  FIG. 10 , the tool mounting portion  54  extends upwardly from the base portion  52 . The tool mounting portion  54  comprises a forward surface  88  facing the operating direction OD, and a rearward surface  90  facing an opposite direction from the forward surface  88 . Further, tool mounting portion comprises an upper surface  92  between the forward and rearward surfaces  88  and  90 . The forward, rearward and upper surfaces  88 ,  90 ,  92  generally define the tool mounting portion  54  extending upwardly from the base portion  52 . 
     The tool body  66  of the processing tool  64  directly abuts the forward surface  88  of the tool mounting portion  54 , as illustrated in  FIG. 5 . With concurrent reference to  FIG. 14 , the processing tool  64  is positioned within a forward recess  94  defined by or adjacent to the forward surface  88  of the tool mounting portion  54  and a leading upper surface  96  of the base portion  52 . The forward recess  94  is sized and shaped such that the leading edge  72  of the processing tool  64  is adjacent the second raker surface  84  when the processing tool  64  is coupled to the tool holder  48 . 
     During operation of known processing tool systems, processed material often undesirably contacts the tool holder and/or rotary drum behind the processing tool. That is, immediately after the material is reduced by the processing tool, the rotating processing tool causes the upper surface of the tool holder to contact the reduced material. In addition to increased wear on the upper surface of the tool holder, the result is associated with disadvantages remedied by the present disclosure. 
     The processing tool  64  comprising an upper flange  98 . When the processing tool  64  is coupled with the tool holder  48 . The upper flange  98  is positioned adjacent and extends above at least a portion of the upper surface  92  of the tool holder  48 . More specifically, the upper flange  98  may directly abut at least a portion of the upper surface  92  of the tool mounting portion  54 . As illustrated in  FIG. 5 , the upper flange  98  extends rearwardly (i.e., opposite the operating direction OD) above the upper surface  92 . The upper flange  98  directs the processed material away from the upper surface  92  and the rearward surface  90  of the tool mounting portion  48  during operation of the material reduction system  34 . 
       FIG. 10  illustrates a representative material path MP during operation of the material reducing system  34 . The material path MP is generated by the processing tool system  46  moving relative to the material as the processing tool system  46  rotates via the rotary drum  40 . As described in detail above, the material may first contact the raker  86  of the base portion  52 . More specifically, the material contacts the raker surface  74 . The material path MP is altered based on the first predefined angle α 1 , α 1 ′ defined by the raker surface  74 . Further based on the second predefined angle α 2 , α 2 ′ defined by the leading face  72  of the processing tool  64 , the material path MP contacts the reducing member  68  and material contact with the tool body  66  is limited. Preferably, the material path MP engages the reducing member  68  at a predefined depth to optimize the operation, which may be based on the horsepower of the material processing machine  30 , the type of reducing member  68 , and the like. 
     After the material is processed, the material path MP typically trends towards the upper surface  92  of the tool holder  48 . Based on the length (i.e., distance between forward surface  88  and rearward surface  90 ) of the tool mounting portion  54  of the tool holder  48 , the material would contact the tool mounting portion  54  in the absence of the upper flange  98  of the present disclosure. Yet, advantageously, the upper flange  98  sufficiently redirects the material path MP such that at least most of the material is prevented from contacting the upper surface  92  and the rearward surface  90 , as illustrated in  FIG. 10 . 
     The upper flange  98  may comprise any length W and thickness T as necessary. In the exemplary embodiment, the length W of the upper flange  98  extends rearwardly above the upper surface  92  for only a portion of the same. The present disclosure contemplates that the length W of the upper flange  98  may comprise 10, 25, 75, 100 percent or more of the width of the tool mounting portion  48 . In one example, the upper flange  98  directly abuts the entire upper surface  92  and terminates proximate to the rearward surface  90 . In another example, the upper flange  98  may extend beyond the rearward surface  90 . Similarly, the thickness T may be ¼, ½, 1 or more inches. Consideration may be given to the positioning of the reducing member  68  based on different thicknesses T of the upper flange  98 . The present disclosure further contemplates the upper flange  98  may be planar as shown in  FIG. 10 , but alternatively may be curved, tapered outwardly or inwardly, and the like. 
     Based on the anticipated wear to the upper and rearward surfaces of known tool processing systems, the material processing systems known in the art undesirably require complex fastening means to removably couple the processing tool to the tool holder. During repair or replacement of processing tools of known tool processing systems, appreciable time and expense is expended decoupling and/or coupling the replacement processing tool. Furthermore, fabricating components with complex fastening means, including the fastener itself, is also undesirable for obvious reasons. 
     As described, however, the processing tool system  46  of the present disclosure overcomes the above shortcomings by at least minimizing contact between the material and the tool holder  48  after the material has passed the processing tool  64 . Consequently, less complex fastening means can be incorporated, which reduces downtime during repair or replacement. 
     Referring to  FIGS. 10 and 12 , the fastener  73  couples the processing tool  64  and the tool mounting portion  54 . The fastener  73  extends through the borehole  75  within the tool mounting portion  54  of the tool holder  48 . The fastener  73  may comprise a bolt having threads configured to engage internal threads of a bore  103  within the tool body  66  of the processing tool  64  (see  FIG. 14 ). A spacer  102  may be disposed adjacent the head  104  of the fastener  73  as commonly known in the art. The spacer  102  may be a ring washer, spring washer, bushing, and the like. 
     When coupling the processing tool  64  and the tool holder  46 ,  FIG. 10  shows the head  104  of the fastener  73  disposed with a rearward recess  106  defined by or adjacent to the rearward surface  90  of the tool mounting portion  54  and a trailing upper surface  108  of the base portion  52  (see also  FIG. 14 ). The rearward recess  106  is suitably sized and shaped such that the material path MP substantially avoids contacting the head  104  of the fastener  73  during operation of the material reduction system  34 . In the exemplary embodiment illustrated in  FIG. 10 , the rearward surface  90  is oriented at a right angle relative to the trailing upper surface  108 . In another exemplary embodiment illustrated in  FIG. 12 , the rearward surface  90  is oriented at an obtuse angle relative to the trailing upper surface  108 . Typically, the rearward surface  90  is vertical (i.e., when the processing tool system  46  oriented similar to  FIG. 10 ) such that the head  104  appropriately contacts the rearward surface  90  as the fastener  73  extends horizontally through the tool mounting portion  54 . 
     Based on the characteristics of the rearward cavity  106  as well as the altered material path MP due to the upper flange  98  of the processing tool  64 , the head  104  of the fastener  73  may be positioned adjacent and/or external to the tool mounting portion  54  of the tool holder  48 . The borehole  75  does not require a counterbore, a countersink, or other similar structure to recess the fastener  73 , as the contact between the material and the tool holder  48  is already minimized. In addition, the fastener  73  may comprise a standard Hex bolt. Consequently, the fastener  73 , and therefore the processing tool  64 , may be quickly decoupled and coupled, reducing downtime. Further, the incorporation of a standard Hex bolt avoids the need for specialized tools to perform repairs or replacement of the processing tool  64 . Still further, the lack of, for example, the counterbore may decrease fabrication costs of the tool holder  48 . These and additional advantages of the present disclosure are readily apparent to those having skill in the art. 
     As the processing tool system  46  encounters more robust materials such as trees with larger trunks, stumps, and the like, each of the processing tool system  46  may effectively generate a “channel” within the material. The channel comprises a width substantially equal to a width of the processing tool. In known systems, however, the opposing sides of the tool holder undesirably experience significant friction from the channel—a concept known as “wedging”—hampering performance of the material reducing system. Features of the present disclosure provide advantages over these known systems. 
     Referring to  FIG. 11 , the tool holder  48  comprises two opposing sides  110  that define a width W TH  of the tool holder  48 . Likewise, the processing tool  64  comprises two opposing sides  112  that define a width W PT  of the processing tool  64 . The width W PT  of the processing tool  64  may be greater than the width W TH  of the tool holder  48 . 
     The differences in widths W PT , W TH  is such that the reducing members  68  of the processing tool  64  create a wider channel in the material than the width W PT  of the processing tool  64 . In one example, one half of the difference, Δ, may be between 0.05 to 0.5 inches. In another non-exhaustive example, Δ may be between 0.25 and 0.35 inches, but other values are contemplated. The result effectively limits the friction between the processing tool system  46  and the channel to the length (i.e., from the reducing member  68  to the rearmost point of the upper flange  98 ) of the processing tool  64  as opposed to the length of the tool holder  48  (i.e., forward point of leading member  56  to rearward point of trailing member  58 ). The reduction in friction, particularly when aggregated over one, two, three or more dozen processing tool systems  46  disposed on the rotary drum  40 , may greatly improve the overall efficiency of the material reduction system  34 . 
     Efficient decoupling and coupling of the processing tool  64  and the tool holder  48  is one of the many advantages of the present disclosure. In addition to the accessibility and simplicity of the fastener  73 , improved coupling may further be facilitated by an interlock  114  between the processing tool  64  and the tool holder  48  ( FIG. 5 ). Referring to  FIGS. 14 and 16 , a projection  116  extends from the tool mounting portion  54  of the tool holder  48 . More specifically, the forward surface  88  of the tool mounting portion  54  defines the projection  116  facing the operating direction OD. The projection  116  is positioned superiorly to at least a portion of the leading upper surface  96  of the base portion  52 . The projection  116  may further define the forward recess  94  within which the processing tool  64  is positioned when the processing tool  64  and the tool holder  48  are coupled. 
     A lower flange  118  comprises a portion of the tool body  66 .  FIG. 16  shows the lower flange  118  extending from the tool body  66  opposite the leading face  72 . The lower flange  118  may generally extend in the same direction from the tool body  66  as the upper flange  96 . The lower flange  118  may be parallel to the upper flange  96 . The upper flange  96 , the lower flange  118 , and the projection  116  may define the interlock  114 . 
     The lower flange  118  defines a tool recess  120  between the upper flange  96  and the lower flange  118 . In the exemplary embodiment illustrated in  FIG. 16 , the tool recess  120  is generally rectangular in shape, but other suitable shapes are contemplated such as triangular, hemispherical, and the like. The surfaces of the upper flange  96 , lower flange  118 , and tool recess  120  may define a tool mounting surface  122 . The projection  116  is sized and shaped to fit snugly within the tool recess  120 . The projection  116  is configured to removably be disposed within the tool recess  120  when the processing tool  64  is coupled to the tool holder  48 , as illustrated throughout the figures. 
     The positioning of the projection  116  within the tool recess  120  prevents rotation of the processing tool  64  relative to the tool holder  48  during installation, removal, operation, and otherwise. In other words, the projection  116  and the tool recess  120  create an interference fit such that the processing tool  64  is prevented from rotating relative to the tool holder  48 . For example in the context of coupling the processing tool  64  and the tool holder  48 , the processing tool  64  is positioned on the leading upper surface  96  and slidably moved towards the tool mounting portion  54  such that the tool mounting surface  122  directly abuts the leading surface  88  of the tool holder  48 . The lower flange  118  is positioned within the leading recess  94 , and the projection  116  is positioned within the tool recess  120 . The fastener  73  is passed through the borehole  75  such that the fastener  73  engages the bore  103  of the processing tool  64 . As the fastener  73  is tightened, the processing tool  64  is prevented from rotating, permitting the installer to quickly tighten the fastener  73  to the desired torque. 
     Furthermore, during operation of the processing tool system  46 , the interlock  114  may reduce stress on the fastener  73  and/or provide for increased security at the interface between the processing tool  64  and the tool holder  48 . As compared to, for example, known systems where two planar abutting surfaces that may translate relative to one other, the present disclose provides that the upper flange  96 , projection  116  and lower flange  118  interlock to prevent such translation. Thus, as material engages the reducing member  68 , the processing tool  64  experiences significant forces in a direction opposite the operating direction OD. Rather than the fastener  73  bearing substantially an entirety of the forces, the shared surfaces (i.e., the leading surface  88  and the tool mounting surface  120 ) between the upper flange  96  and projection  116  and the projection  116  and lower flange  118  distribute the forces in an improved manner. The likelihood of processing tool failure during operation (i.e., where the tool is decoupled from the tool holder during operation of the machine, and often ejected at high speeds) may be reduced, promoting operational safety of the material reducing operation. 
     As mentioned, the time and expense associated with replacing or repairing the processing tool is typically a fraction of the time and expense associated with repairing or replacing the tool holder and/or the rotary drum. The additional time and expense is often due to the repairs or steps associated with welding or otherwise securing the tool holder to the rotary drum in a suitable manner. If tool holders fail during operation, it is typically a result of structural failure at or proximate to the weld fixedly securing the tool holder to the rotary drum. Most known tool processing systems comprise welding at the junction between the opposing sides of the tool holder and the outer surface of the rotary drum. The lack of suitable weld penetration often increases the likelihood of structural failure at or proximate to the weld. 
     The material reduction system  34  comprises set offs  124   a ,  124   b  extending from the tool holder  48 . Referring to  FIG. 14 , the set offs  124   a ,  124   b  comprise a portion of the base portion  52  of the tool holder  48  and extend inferiorly from the base portion  52 . The set offs  124   a ,  124   b  are preferably integral or unitary with the base portion  52 , but discrete set offs that are coupled to the base portion are also contemplated. In the exemplary embodiment illustrated in  FIG. 14 , the set offs  124   a ,  124   b  comprise one set off  124   a  extending from the leading member  56 , and another set off  124   b  extending from the trailing member  58 . While two set offs  124   a ,  124   b  are shown, any number of set offs may be included. Further, the present disclosure contemplates the set offs  124   a ,  124   b  may be positioned as shown in  FIG. 14  or at any point along the mounting surface  60 . 
     In many respects, the set offs  124   a ,  124   b  function as legs of the tool holder  48 . That is, the set offs  124   a ,  124   b  are configured to be positioned in direct contact with the rotary drum  40  when the tool holder  48  is fixedly mounted on the rotary drum  40 . The set offs  124   a ,  124   b  define a gap  126  between the mounting surface  60  of the tool holder  48  and the outer surface  42  of the rotary drum  40 . In one example, the gap  126  may be between 0.05 to 0.15 inches. In another non-exhaustive example, the gap  126  may be between 0.0625 and 0.09 inches, but other values are contemplated. The size of the gap  126  is typically equal to the height of the set offs  124   a ,  124   b . Likewise, the width W SO  of the set offs  124   a ,  124   b  may be any suitable width desired such as ¼, ½, 1 or more inches. 
     When positioned in direct contact with the outer surface  42  of the rotary drum  40 , the gap  126  may extend along the mounting surface  60  between the set offs  124   a ,  124   b . During the welding process, the weld is able to penetrate the gap  126  and weld or otherwise fuse greater areas of the mounting surface  60  and the outer surface  42  as opposed to only the edges shared between the tool holder and the rotary drum. Those having skill in the art readily appreciate the increase in strength associated with greater weld penetration. 
     In addition to increased weld penetration, the present disclosure contemplates an improved method for welding the tool holder  48  to the rotary drum  40 . The tool holder  48  may be comprised of hardened steel, whereas the rotary drum  40  may be comprised of softer steel such as SAE 1010, 1020 or 1026 that is electric resistance welded (ERW) or drawn over mandrel (DOM). As known in the welding art, softer steel draws the weld to a greater extend than hardened steel. Consequently, the method comprises the step of heating the tool holder  48  prior to welding the tool holder  48  to the rotary drum  40 . The heating of the tool holder  48  softens the hardened steel, thereby drawing a greater relative amount of the weld for improved weld strength. 
     Referring now to  FIGS. 15 and 16 , an exemplary embodiment of the tool body  66  is shown. The tool body  66  comprises a top surface  128  opposite a bottom surface  130 . The opposing sides  112  are separated by the top and bottom surfaces  128 ,  130 . As mentioned, the tool body  66  may comprise a portion of the leading face  72  facing the operation direction OD. The tool mounting surface  122  is opposite the leading face  72  and configured to directly abut at least a portion of the tool holder  48 , and more particularly the forward surface  88  of the tool mounting portion  56 . The leading face  72  may be substantially planar and oriented towards the operating direction OD. The upper flange  96  may comprise a portion of the top surface  128 , and the lower flange  118  may comprise a portion of the bottom surface  130 . The upper flange  96  and the lower flange  118  define the tool recess  120 . 
     The processing tool  64  further comprises a cavity  132  as shown in  FIGS. 15 and 16 . The cavity  132  is disposed within the tool body  66 . More specifically, the cavity  132  is defined by a portion of the top surface  128  and a portion of the leading face  72 . The cavity  132  is configured to receive the reducing member  68 . In other words, the reducing member  68  are positioned or disposed within the cavity  132  when coupled to the processing tool body  66 . The reducing member  68  is typically welded or brazed to the tool body  66  when disposed within the cavity  132 , but other joining means are contemplated. 
       FIGS. 17-19  illustrate exemplary embodiments of the reducing member  68  comprising two processing teeth  70   a - 70   c  arranged in a side-by-side configuration. Referring first to  FIG. 17 , the processing teeth  70   a  are generally rounded and configured to handle impact and abrasion. The processing teeth  70   a  may each be approximately two inches wide, but the present disclosure contemplates any suitable width. The processing teeth  70   a  of  FIG. 17  may be designed primarily for forestry mowers with greater than 200 horsepower. A narrower version of the processing tool  64  of  FIG. 17  may be designed for applications with less than 200 horsepower. 
       FIGS. 18 and 19  illustrate processing teeth  70   b ,  70   c  directed to chipping material. The processing teeth  70   b ,  70   c  comprise generally planar surfaces not particularly suited for abrasive applications. The processing teeth  70   b  of  FIG. 18  are typically designed for forestry mowers having greater than 200 horsepower such that the processing teeth  70   b  “push thru” the material. The processing teeth  70   b  of  FIG. 18  comprise indents and are typically designed for forestry mowers having less than 200 horsepower. Other sizes and shapes of the processing teeth are contemplated consistent with the objects of the present disclosure described herein. 
     Several embodiments have been discussed in the foregoing description. However, the embodiments discussed herein are not intended to be exhaustive or limit the invention to any particular form. The terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the invention may be practiced otherwise than as specifically described.