Abstract:
The present invention relates to rollers subjected to wear conditions and surface reinforcements for such rollers. More specifically, the present invention relates to the orientation of projections on the rollers or surface segments of such rollers. In one embodiment, the roller includes a hub. The roller also includes a plurality of removable surface segments attachable to the hub so as to form a layer around the hub. Each surface segment has two opposed sides and an exterior surface. The spacing between projections across the exterior surface decreases from each of the opposed sides to an intermediate point between the opposed sides.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of International App. No. PCT/CA2015/050122 entitled “ROLLER AND REPLACEABLE SURFACE SEGMENTS FOR ROLLER” filed on Feb. 18, 2015; which claims priority on U.S. App. No. 61/941,746 entitled “ROLLER AND REPLACEABLE SURFACE SEGMENTS FOR ROLLER” filed on Feb. 19, 2014, and U.S. App. No. 62/076,117 entitled “SEGMENTED ROLLER AND METHOD OF RECONDITIONING SAME” filed on Nov. 6, 2014, all of which are incorporated by reference herein in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to rollers subjected to wear conditions and surface reinforcements for such rollers. More specifically, the present invention relates to the orientation of surface studs on the rollers or surface segments of such rollers. 
       BACKGROUND 
       [0003]    Friction-based rollers are common components of many machines. A frequent problem with such rollers is wear on the roller surface over time, particularly if the roller is subjected to large frictional forces. When the surface of the roller begins to wear out or becomes uneven, the roller must then be replaced or the surface of the roller must be remanufactured in some way. 
         [0004]    Frictional wear is particularly problematic for industrial rollers used to crush, compact, shred, or grind materials. Industrial rollers are used extensively in mining operations to break up rock, ore, and other brittle materials into smaller particles. Industrial rollers can also be used for trash compaction or in other applications where high throughput crushing, shredding, or compaction is required. Two basic types of industrial rollers are commonly used; the first being a single roller operating adjacent to a stationary curved anvil plate and the second being a double counter-rotating set of rollers having parallel axes and a gap between the rollers. 
         [0005]    Particle output size from a roller or pair of rollers is determined by the size of the gap, also known as the ‘nip’, between the roller surface and the opposing surface, such as an anvil plate or opposing roller. Material is drawn into the nip by the rotating motion of the roller surface and exits the nip in a continuing stream of crushed, compacted, or shredded material. 
         [0006]    In many industrial applications, particularly in the mining industry, industrial rollers are subjected to extremely high pressures and/or are used to crush relatively hard materials, both of which can result in significant frictional wear on the rollers. A common symptom of such wear is known as ‘dishing’, in which the surface of the roller develops a concave profile over time. Wear patterns tend to be most pronounced at the centre of the outer surface of the roller and progressively decrease between the centre of the outer surface of the roller and the both edges of the outer surface of the roller. The resulting unevenness in the roller surface can be problematic as it varies the effective size of the nip across the axial length of the roll and the particulate size of the material output by the roller varies accordingly. 
         [0007]    One conventional approach to extending the life of an industrial roller is to reinforce the roller surface with extremely hard materials, such as tungsten carbide. In view of the higher costs of such materials, an outer shell is often applied over an inner drum, rather than manufacturing the entire roller out of the (more expensive) harder material. Nevertheless, even the hardest materials will wear out over time and so this approach can only extend the time required before the roller must be replaced or remanufactured in order to provide an even surface. 
         [0008]    Industrial rollers also often have surface features such as teeth, blades, or studs that assist the roll surface in directing material into the nip and also assist with the crushing or shredding action of the roller. Depressions or grooves on the roller surface can also be used to retain milled material on the roller surface, as a means of reducing wear on the roller surface. However, like the roller surface itself, surface features also wear out over time due to friction, even if they are constructed from relatively hard materials. 
         [0009]    Conventional crushing rollers used in the mining industry use an array of tungsten carbide studs as a surface reinforcement. The carbide studs are inserted into a plurality of holes distributed across the surface of the roller and the studs are typically welded in place. Thus the positioning of the holes dictates the positioning of the studs upon the roller. In operation, the studs act as teeth to assist in the grinding action and the spaces between the studs retain milled material and so protect the underlying roller surface from wear. Over time, the studs wear out, often in an uneven manner, and the underlying roller surface can also be subjected to uneven wear. 
         [0010]    When an industrial roller reaches the end of its service life, it must be replaced or remanufactured. In many applications, particularly in the mining industry, industrial rollers can be quite large and so remanufacture is often preferred over complete replacement of the roller. 
         [0011]    The remanufacture of a worn roller is not a simple or inexpensive task, involving removal of the entire drum from service, followed by extensive cutting, machining, and rewelding of the surface of the drum. 
         [0012]    For rollers in the mining industry that rely on carbide studs, it is not uncommon to cut off the studs using a lathe and begin the painstaking process of installing new studs on the roller surface. For example, U.S. Pat. No. 8,316,543 to Patzelt et al. describes one process in which the surface of the roller is machined and the reconditioned surface is built back up using a welding process to deposit new surface material. New holes are then drilled in the rebuilt surface and new studs are set into place. U.S. Patent Application No. 2012/0138722 A1 by Brendler describes a similar approach, in which surface features on the worn roller are cut off, a radial groove is machined into the reconditioned roller surface, new features are set into either side of the groove, and a form fitting body is inserted between the features to fill in the machined groove and hold the features in place. 
         [0013]    As can be understood by the person of skill in the art, methods which rely on turning or machining an industrial roller will result in a reduction in the diameter of the remanufactured roller, unless new material is welded onto the surface to replace the material lost during the reconditioning process. For industrial rollers which employ studs, conventional methods require a new array of receiving holes to be drilled on the roller surface. 
         [0014]    Regardless of the method used during remanufacture, the need for secure attachment of the surface reinforcements to the roller drum and the reliance in the art on welding for attaching features to the roller surface makes remanufacture of worn out rollers difficult, expensive, and labour intensive. 
       SUMMARY OF THE INVENTION 
       [0015]    It is an object of the present invention to provide an improved roller incorporating projections that will limit frictional wear upon the roller&#39;s outer surface. 
         [0016]    In the present invention, projections are orientated on the surface of the roller to limit the wear upon the surface of the roller. 
         [0017]    In the present invention, projections are orientated on the surface of the roller to limit the wear upon the central surface of the roller. 
         [0018]    Accordingly, a reinforced roller is provided in one preferred embodiment. The roller has two side edges and a median line between the side edges. The roller also has an outer surface between the side edges incorporating adjacent surface features. The adjacent surface features are each separated by a distance wherein the distance between a first set of two adjacent surface features proximate to one of the side edges exceeds the distance between a second set of two adjacent surface features proximate to the median line. 
         [0019]    In another embodiment, the reinforced roller includes an inner roll. The reinforced roller also includes a plurality of removable outer segments attachable to the inner roll so as to form a layer around the inner roll. Each outer segment has two side edges, a median line between the side edges and an outer segment surface between the side edges. Adjacent surface features projecting above the outer segment surface are each separated by a distance wherein the distance between a first set of two adjacent surface features proximate to one of the side edges exceeds the distance between a second set of two adjacent surface features proximate to the median line. 
         [0020]    In another embodiment there is provided a roller for crushing, grinding, or otherwise contacting a material, the roller comprising:
       a cylindrical body rotatable about a central axis, the body comprising:   a first and second opposed ends; and   a working surface disposed between the opposed sides, the working surface comprising:   a plurality of projections for crushing, grinding, or otherwise contacting a material, wherein the spacing of the projections across the working surface decreases from each of the opposed sides to an intermediate point between the opposed ends.       
 
         [0025]    In another embodiment there is provided a roller assembly for crushing, grinding, or otherwise contacting a material, the assembly comprising:
       a hub configured for mounting to an axle, said hub rotating about a central axis and having an outer surface comprising one or more engagement structures, and;   a plurality of surface segments configured for attaching to said one or more engagement structures of said hub, said segments each comprising:
           an exterior surface for contacting material at a working surface of the roller assembly;   an interior surface opposed to said exterior surface configured to engage an engagement structure disposed on the outer surface of the hub, thereby covering at least a portion of the outer surface of the hub;   a leading edge and a trailing edge joining the exterior surface to the interior surface;   a first and second opposed sides joining the outer surface to the inner surface; and   a plurality of projections for crushing, grinding, or otherwise contacting a material, wherein the spacing of the projections across the exterior surface decreases from each of the opposed sides to an intermediate point between the opposed sides.   
               
 
         [0033]    In another embodiment there is provided a roller assembly for crushing, grinding, or otherwise contacting a material, the assembly comprising:
       a hub configured for mounting to an axle, said hub having an outer surface comprising one or more engagement structures; and   a plurality of surface segments configured for attaching to said one or more engagement structures of said hub, said segments each comprising:
           an exterior surface for contacting material at a working surface of the roller assembly;   an interior surface opposed to said exterior surface of the surface segment configured to engage an engagement structure disposed on the outer surface of the hub, thereby covering at least a portion of the outer surface of the hub;   a leading edge and a trailing edge joining the outer surface to the inner surface;   a first and second opposed sides joining the outer surface to the inner surface; and   a plurality of projections for crushing, grinding, or otherwise contacting a material, wherein the spacing of the plurality of projections across the exterior surface decreases from each of the edges to an intermediate point between the between the edges.   
               
 
         [0041]    In another embodiment there is provided a surface segment comprising:
       an exterior surface for contacting material at a working surface of the roller assembly;   an interior surface opposed to said exterior surface configured to engage an engagement structure disposed on the outer surface of the hub, thereby covering at least a portion of the outer surface of the hub;   a leading edge and a trailing edge joining the exterior surface to the interior surface;   a first and second opposed sides joining the outer surface to the inner surface; and   a plurality of projections for crushing, grinding, or otherwise contacting a material, wherein the spacing of the projections across the exterior surface decreases from each of the opposed sides to an intermediate point between the opposed sides.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0047]    The invention will now be described with reference to the attached drawings, which illustrate, by way of example only, embodiments of the invention contemplated herein: 
           [0048]      FIG. 1  is a perspective view of the roller according to one embodiment of the invention; 
           [0049]      FIG. 2  is a perspective view of one surface segment fastened to the axle and hub according to one embodiment of the invention; 
           [0050]      FIGS. 3A and 3B  are perspective views of the axle ( FIG. 3A ), and inner roll or hub ( FIG. 3B ); 
           [0051]      FIG. 4  is a perspective view of a surface segment of the roller shown in  FIG. 2 ; 
           [0052]      FIG. 5  is a top view of a surface segment according to one embodiment of the invention; 
           [0053]      FIG. 6  is a side view of the surface segment shown in  FIG. 5 ; 
           [0054]      FIG. 7  is an additional side view of a surface segment according to one embodiment of the invention; 
           [0055]      FIGS. 7A and 7B  are sectional views of the surface segment along lines G-G and H-H, respectively, from  FIG. 7 ; 
           [0056]      FIG. 8  is a further top view of the surface segment according to one embodiment of the invention; 
           [0057]      FIGS. 8A to 8D  are sectional views of the surface segment along lines A-A, B-B, C-C and D-D, respectively, from  FIG. 8 ; 
           [0058]      FIGS. 8E and 8F  are detailed views of portions E and F of the surface segment, respectively, from  FIG. 8 ; 
           [0059]      FIG. 9  is a further top view of a surface segment according to one embodiment of the invention; and 
           [0060]      FIG. 9A  is a detailed view of portion M of the surface segment from  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0061]    Referring to the drawings, various embodiments of the invention will now be disclosed. 
         [0062]    Referring to  FIG. 1 , the roller  100  is in general terms a cylindrical body  102  rotatable about a central axis, the body  102  having a working surface  104  for crushing, grinding, shredding, rolling, or otherwise contacting a material (not shown) and a first and second opposed ends ( 106 ,  108 ). 
         [0063]    Referring to  FIG. 1 ,  FIG. 2 , and  FIGS. 3A and 3B , Roller  100  comprises a central hub  120  and a plurality of surface segments  130  which will be discussed in more detail below. Turning to  FIGS. 3A and 3B , hub  120  has an outer surface  122  and a central bore  124 . Roller  100  can be mounted on an axle  110  through bore  124 , whereby rotation of shaft  110  drives roller  100 . Shaft  110  can be rotatably driven by any drive or drive mechanism (not shown) known in the art suitable for driving a roller assembly  100  of the type disclosed herein. Further mechanical components may also be provided as appropriate, such as a gearbox, emergency disconnect and other known components, not shown but conventional. 
         [0064]    Referring to  FIGS. 1 to 4 , the plurality of surface segments  130  are mounted to the outer surface  122  of hub  120 . The surface segments  130  form some, substantially all, or all, of the working surface  104  of the roller  100 . In a preferred embodiment, each of the surface segments  130  has an arcuate form such that the placement of a plurality of surface segments  130  on the hub  120  results in a substantially cylindrical working surface for the roller  100 . In a preferred embodiment, eight surface segments  130  are disposed upon the hub  120 . Each surface segment  130  is disposed as closely as possible to adjacent surface segments  130 , preferably at a gap of 0.25 millimeters apart. 
         [0065]    Referring to  FIGS. 4, 5, 6, and 7 , it will be understood that each surface segment  130  has an exterior surface  132  for contacting material at a working surface  104  of the roller  100 . Opposed to the exterior surface  132  is an interior surface  134  for engagement with hub  120 . The exterior surface  132  and the interior surface  134  of the surface segment  130  are joined together by a leading edge  136  and a trailing edge  138 . When the surface segments  130  are assembled to form the roller  100 , and the roller  100  is made to roll, the leading edge  136  is to be understood as the portion of the surface segment  130  that leads in the direction of rotation and the trailing edge  138  is that portion of the surface segment  130  that trails behind the leading edge  136 . As mentioned above, surface segment  130  has an arcuate form, and in an embodiment, the angle θ subtended by the leading edge  136  and the trailing edge  138  is about 45 degrees. 
         [0066]    Again, with reference to  FIGS. 4, 5, 6, and 7 , the exterior surface  132  and the interior surface  134  of the surface segment  130  are also joined together by opposed first side  140  and second side  142 . It will be understood that when the surface segments  130  are assembled to form the roller  100 , the opposed first  140  and second sides  142 , form portions of the opposed first ends  106  and second ends  108  of the cylindrical body  102 . 
         [0067]    The interior surface  134  of the surface segment  130  will now be described in detail with reference to  FIG. 2 ,  FIG. 3B , and  FIG. 4 . Surface segments  130  can be engaged to the hub  120  at engagement structures  126 ,  144 . In  FIGS. 2 and 3B , the engagement structures  126 ,  144  are provided as a male member, in this case a rectangular ridge  126 , on the outer surface  122  of the hub  120 , which interlocks with a corresponding female member, in the case a rectangular groove  144 , on the interior surface  134  (i.e. the underside) of surface segment  130 . The ridge  126  extends radially outwards from the hub  120  and along the axial length of the roller  100 , parallel to its central axis. The ridge  126  is received in a corresponding groove  144  on the interior surface  134  of the surface segment  130 , thereby providing stability to the surface segment  130  when the roller  100  is in motion, particularly with regard to torsional forces. 
         [0068]    As depicted in  FIG. 2  and  FIG. 3B , the engagement structures  126 ,  144  have an interlocking rectangular profile. Alternative interlocking structures are also contemplated, including dovetailed, T-shaped, or similar profiles which limit movement of the surface segment  130  in the radial direction. Similarly, arrangements in which the male member is provided on the surface segment  130  and the female member is provided on the hub  120  are also contemplated. 
         [0069]      FIG. 2  depicts a surface segment  130  fastened to hub  120 . In this example, the connection between the male and female members at the engagement structures  126 ,  144  is secured by a plurality of bolts  145 , which pass through corresponding bolt holes  146  in the surface segment  130  and secures into a corresponding threaded hub hole  128  in the outer surface  122  of the hub  120 . Likewise, although  FIG. 3B  depicts fastening of the surface segments  130  in a radial direction, fastening is also contemplated in an axial direction, particularly where the engagement structures interlock using a profile which prevents movement in the radial direction. 
         [0070]    The number of bolt holes  146  in surface segment  130  can vary, as can the pattern in which the bolt holes  146  appear upon the surface segment  130 . In embodiments, the bolt holes  146  are aligned in two parallel rows of nine bolt holes  146  as shown in  FIG. 5 , or the bolt holes  146  are aligned in two parallel rows of seven bolt holes  146  as shown in  FIGS. 1, 2, and 4 . Various other means of fastening known in the art are also contemplated, such as heat releasable glues, metal screws, heat shrinking and the like. 
         [0071]    The exterior surface  132  of the surface segment  130  will now be described in detail with reference to  FIG. 4 , and  FIG. 5 . Referring to  FIG. 4 , the surface segment  130  incorporates a plurality of projections  150  for crushing, grinding, or otherwise contacting a material. Projections  150  can be studs, pins, blades, teeth or any other protrusion that projects above the exterior surface  132  of the surface segment  130 . The total number of projections  150  may vary depending on the needs and the desired size of the surface segment  130 , and thus roller  100 . 
         [0072]    Projections  150  project outwardly from the working surface  104  of the roller  100  to crush, grind, or otherwise contact a material. In an embodiment, the projections  150  project radially outward from exterior surface  132  of the surface segment  130 . In a preferred embodiment, the projections  150  form rows aligned with the central axis and each row spans from the first side  140  to the second side  142 . In another preferred embodiment, the projections  150  of one row are offset with the projections  150  of adjacent rows in a pattern as depicted more clearly in  FIGS. 4 and 5 . 
         [0073]      FIG. 5  is a top view of one surface segment  130 , and  FIG. 6  is a side view of the first side  140  of the surface segment  130  for a roller  100  in isolation. The surface segment  130  is shown without projections  150 , for illustration purposes. Instead, surface segment  130  is shown having a plurality of apertures  152  bored into the working surface of the surface segment  130 . In the embodiment shown in  FIG. 5 , the apertures  152  are substantially circular and have similar diameters (distances shown in the figures are in millimeters). It will be understood that apertures  152  are dimensioned to receive and solidly fix corresponding projections  150 . The projections  150  are affixed within the apertures  152  by conventional means known in the art, whether by welding, the use of an adhesive or the like. 
         [0074]    The distribution profile of the apertures  152  on the surface segment  130  will now be discussed in greater detail with reference to  FIGS. 5 to 9A . For convenience, it may be understood that each surface segment  130  also has an intermediate point  154  along a line drawn parallel to the central axis of the roller  100  between the first side  140  and the second side  142  as depicted in  FIG. 5 . The intermediate point  154  is not a feature visible upon the surface segment  130  but is used herein merely as reference. Preferably the intermediate point  154  is the midpoint between on a line drawn parallel to the central axis between the first side  140  and the second side  142 . 
         [0075]    As depicted in  FIG. 5 , the apertures  152  form a plurality of rows where each row is aligned parallel to the central axis and each row spans the first  140  and second  142  opposed sides. Reference will now be made to Table 1 below which provides an example of the distribution profile of the apertures  152  on the surface segment  130 . In Table 1, the left and right columns represent the bottom and the top row of apertures  152 , respectively, of the surface segment  130  of  FIG. 5 . The values from top to the bottom of each column represent the distances (in mm) that each of the apertures  152  are from the first side  140  along that particular row. It follows that the values at the top of each column are most proximate to the first side  140  and the values at the bottom of each column are most proximate to the second side  142 . 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Bottom Row 
                 Top Row 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 0 
                 0  
               
               
                   
                 36 
                 33*  
               
               
                   
                 66 
                 51   
               
               
                   
                 95.78 
                  80.89 
               
               
                   
                 125.35 
                 110.57 
               
               
                   
                 154.70 
                 140.03 
               
               
                   
                 183.84 
                 169.27 
               
               
                   
                 212.76 
                 198.30 
               
               
                   
                 241.46 
                 227.11 
               
               
                   
                 269.95 
                 255.71 
               
               
                   
                 298.22 
                 284.09 
               
               
                   
                 326.28 
                 312.25 
               
               
                   
                 354.12 
                 340.20 
               
               
                   
                 381.74 
                 367.93 
               
               
                   
                 409.15 
                 395.44 
               
               
                   
                 436.34 
                 422.74 
               
               
                   
                 463.31 
                 449.83 
               
               
                   
                 490.07 
                 476.69 
               
               
                   
                 516.62 
                 503.35 
               
               
                   
                 542.94 
                 529.78 
               
               
                   
                 569.06 
                 556   
               
               
                   
                 595.38 
                 582.22 
               
               
                   
                 621.93 
                 608.65 
               
               
                   
                 648.69 
                 635.31 
               
               
                   
                 675.66 
                 662.17 
               
               
                   
                 702.85 
                 689.26 
               
               
                   
                 730.26 
                 716.56 
               
               
                   
                 757.88 
                 744.07 
               
               
                   
                 785.72 
                 771.80 
               
               
                   
                 813.78 
                 799.75 
               
               
                   
                 842.05 
                 827.91 
               
               
                   
                 870.54 
                 856.29 
               
               
                   
                 899.24 
                 884.89 
               
               
                   
                 928.16 
                 913.70 
               
               
                   
                 957.30 
                 942.73 
               
               
                   
                 986.65 
                 971.97 
               
               
                   
                 1016.22 
                 1001.43  
               
               
                   
                 1046 
                 1031.11  
               
               
                   
                 1076 
                 1061    
               
               
                   
                   
                 1079*   
               
               
                   
                   
               
             
          
         
       
     
         [0076]    From Table 1 above, it will be understood generally that within one row, the placement of apertures  152  across the working surface is such that the spacing between adjacent apertures  152  decreases from each of the opposed sides  140 ,  142  to the intermediate point  154  between the opposed sides. In this example, the spacing between adjacent apertures  152  most proximate to either the first  140  or second  142  opposed sides is about 30 mm. The spacing between adjacent apertures  152  progressively decreases during the progression from the first  140  or second  142  opposed sides towards the midpoint. In the region most proximate to the midpoint, the spacing between adjacent apertures  152  is reduced to about 26 mm. Numbers marked with an asterisk (*) represent a relatively small number of apertures  160  having a reduced diameter that are included to accommodate for an irregular surface area imposed by the selection of an offset pattern of rows of apertures  152  in this example. 
         [0077]    To differently illustrate the placement of the apertures  152  across working surface, reference will now be made to  FIGS. 7, 7A and 7B .  FIG. 7  depicts another side view of the first side of the surface segment  130  and  FIGS. 7A and 7B  are sectional views of the surface segment  130  along lines G-G and H-H of  FIG. 7 . As seen in  FIGS. 7A and 7B , within a row as defined by lines G-G or H-H, respectively, the spacing between adjacent apertures  152  most proximate the first and second opposed sides  140 ,  142  is greater than the spacing between adjacent apertures  152  most proximate the intermediate point  154  between the first  140  and second  142  opposed sides. 
         [0078]    The values listed in Table 1 are meant as examples. Persons skilled in the art will understand that range of distances are contemplated. For example, the distance between a set of adjacent apertures  152  most proximate to either the first side  140  or the second side  142  is within a range between 28 millimeters and 32 millimeters and the distance between a set of two adjacent apertures  152  most proximate to the midpoint of the surface segment  130  is within a range between 25 millimeters and 27 millimeters. In a further example, the distance between a set of two adjacent apertures  152  most proximate to either the first side  140  or the second side  142  of the surface segment  130  is 30 millimeters and the distance between a set of two adjacent apertures  152  most proximate to the midpoint of the surface segment  130  is 26.32 millimeters. 
         [0079]    In yet a further embodiment, the distribution profile of apertures  152  on the surface segment  130  can also take a form that will now be described with reference to  FIGS. 8, and 8A-8D .  FIG. 8  depicts another side view of the first side of the surface segment  130  and  FIGS. 8A-8D  are sectional views of the surface segment  130  along lines A-A, B-B, C-C, and D-D of  FIG. 8 , respectively. For convenience, it may be understood that each surface segment  130  has an intermediate point  156  between the leading edge  136  and the trailing edge  138 . This intermediate point  156  between the leading edge  136  and the trailing edge  138  can be understood to divide the surface segment  130  into 2 halves as depicted in  FIG. 8 . The intermediate point  156  is not a feature visible upon the surface segment  130  but is used herein merely as reference. Preferably the intermediate point  156  is the midpoint between the leading edge  136  and the trailing edge  138 . 
         [0080]    With reference to  FIGS. 8A and 8B , along each row of apertures  152  defined by lines A-A or B-B, each aperture  152  can be understood as subtending an angle in relation to the intermediate point  156  or any other aperture  152 . As shown in  FIGS. 8A and 8B , the angle subtended between adjacent apertures  152  most proximate to at least one of the edges  136 ,  138  is greater than the angle subtended between adjacent apertures  152  most proximate to an intermediate point  156  between the edges  136 ,  138 . The result is that the spacing between adjacent apertures  152  most proximate to either the leading edge  136  or trailing edge  138  is greater than the spacing between adjacent apertures  152  most proximate the intermediate point  156  between the leading edges  136  and trailing edges  138 . 
         [0081]    Reference will now be made to Table 2 below which provides an example of the distribution profile of the apertures  152  on the surface segment  130  as depicted in  FIG. 8A . In Table 2, there are 16 apertures  152  where aperture No. 1 is closest to the trailing edge  138  and the aperture No. 16 is closest to the leading edge  136  of the surface segment  130 . The right column lists the angle that each of the apertures  152  subtends with the midpoint between the leading edge  136  and the trailing edge  138 . 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Aperture No. 
                 Degrees from Midpoint 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 1 
                 20.21 
               
               
                   
                 2 
                 17.42 
               
               
                   
                 3 
                 14.63 
               
               
                   
                 4 
                 11.85 
               
               
                   
                 5 
                 9.06 
               
               
                   
                 6 
                 6.27 
               
               
                   
                 7 
                 3.48 
               
               
                   
                 8 
                 .70 
               
               
                   
                 9 
                 2.09 
               
               
                   
                 10 
                 4.88 
               
               
                   
                 11 
                 7.66 
               
               
                   
                 12 
                 10.45 
               
               
                   
                 13 
                 13.24 
               
               
                   
                 14 
                 16.02 
               
               
                   
                 15 
                 18.81 
               
               
                   
                 16 
                 21.60 
               
               
                   
                   
               
             
          
         
       
     
         [0082]    Reference will now be made to Table 3 below which provides an example of the distribution profile of the apertures  152  on the surface segment  130  as depicted in  FIG. 8B . Similar to the Table 2, in Table 3, there are 16 apertures  152  where aperture No. 1 is closest to the trailing edge  138  and aperture No. 16 is closest to the leading edge  136  of the surface segment  130 . The right column lists the angle that each of the apertures  152  subtends with the midpoint between the leading edge  136  and the trailing edge  138 . 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Aperture No. 
                 Degrees from Midpoint 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 1 
                 21.60 
               
               
                   
                 2 
                 18.81 
               
               
                   
                 3 
                 16.02 
               
               
                   
                 4 
                 13.24 
               
               
                   
                 5 
                 10.45 
               
               
                   
                 6 
                 7.66 
               
               
                   
                 7 
                 4.88 
               
               
                   
                 8 
                 2.09 
               
               
                   
                 9 
                 0.70 
               
               
                   
                 10 
                 3.48 
               
               
                   
                 11 
                 6.27 
               
               
                   
                 12 
                 9.06 
               
               
                   
                 13 
                 11.84 
               
               
                   
                 14 
                 14.63 
               
               
                   
                 15 
                 17.42 
               
               
                   
                 16 
                 20.21 
               
               
                   
                   
               
             
          
         
       
     
         [0083]    In one embodiment, a first angle subtended between adjacent projections  150  proximate to at least one of the edges  136 ,  138  is 0.01 degrees greater than a second angle subtended between adjacent projections  150  proximate to intermediate point  156  between the edges  136 ,  138 . 
         [0084]    The surface segment  130 , and thus roller  100 , may have any dimension known by those skilled in the art suitable for crushing, grinding, or otherwise contacting a material. The total number of projections  150  formed on the surface segment  130  can vary depending on the desired size of the surface segment  130 , and thus the roller  100 . 
         [0085]    Projections  150  may have any desired height or diameter. With reference to  FIGS. 1, 4, 5, 7, 7A-7B, 8, 8A-8F, 9, and 9A , while the majority of protrusions  150 , and thus apertures  152 , are of similar diameter across the working surface of the roller  100 , it will be understood that a relatively small number of protrusions  150 , thus apertures  152 , may have slightly smaller diameters, such as for example apertures  160  and/or different spacing between apertures  152  and  160  to accommodate for other structures. In particular, as shown in  FIGS. 5, 7, 7A-7B, 8, 8A-8F, 9, and 9A , apertures  160  located proximate to the first  140  or second sides  142 , or between bolt holes  146 , or between the bolt holes  146  and the first  140  or second sides  142  may have a different sized diameters and spacing than that for the majority of the protrusions  150  and apertures  152  shown, for example, in  FIGS. 1, 4, 5, and 8 . 
         [0086]    Furthermore, projections  150  can have the repeating pattern as shown, for example, in  FIG. 5  where apertures  152  in one row are offset in relation to the apertures  152  of an adjacent row. Alternatively, the projections  150  may form any other repeating pattern and apertures  152  in one row can be in-line with the apertures  152  of an adjacent row. 
         [0087]    In operation, a roller assembly  100  according to the present invention may be used in the conventional manner. For example, the roller assembly  100  may be positioned opposite to a fixed anvil (not shown) or an opposing counter-rotating roller (not shown) to crush, compact, or shred materials fed to the roller  100 . In some embodiments, the counter-rotating roller is also manufactured according to the present invention. Material fed into the roller  100  enters the nip, where the surface segments  130 , either alone or in combination with projections  150 , crush, shred, or compact material as it passes through the nip. 
         [0088]    If the surface segments  130  are bolted in place, the surface segments  130  may be removed by extracting the bolts  145  from the hub holes  128  and bolt holes  146 . If the surface segments  130  are glued in place or shrink-fit, the roller  100  or the segments  130  being removed may be heated to a sufficiently high temperature to destroy the glue or release the shrink-fitting. In any event, hammering may also be required to free the surface segments  130 , particularly if the roller  100  has been fouled with dirt or ground material during its operation. 
         [0089]    If the surface segments  130  also carry projections  150  such as studs, teeth, depressions, grooves, paddles, or blades, the replacement of the surface segments  130  also results in the replacement of the projections  150  on the roller  100 . Accordingly, the remanufacture process can also be used when the projections  150  are worn, before the underlying surface segments  130  which carry them also become worn. 
         [0090]    While the orientation of the apertures  152  and the corresponding projections  150  has been described in reference to a surface segment  130 , the same orientation disposed directly on a roller  100  without a plurality of surface segments  130  is contemplated. Additionally, while the surface segments  130  have straight edges so that they are easily interconnected with sides  140 ,  1 . 42  corresponding with a cylindrical shaped hub  120 , surface segments  130  appearing in any shape which may be interconnected to substantially cover a cylindrical shaped hub  120  are contemplated. Included within such shaped segments are the segments  130  which are the subject of a co-pending U.S. provisional application by CSP Innovative Engineering Ltd. entitled “Roller With Replaceable Surface Segments and Method of Reconditioning Same”, filed Feb. 19, 2014, which is incorporated herein by reference. 
         [0091]    The embodiments of the present application described above are intended to be examples only. Those of skill in the art may effect alterations, modifications and variations to the particular embodiments without departing from the intended scope of the present application. In particular, features from one or more of the above-described embodiments may be selected to create alternate embodiments comprised of a subcombination of features which may not be explicitly described above. In addition, features from one or more of the above-described embodiments may be selected and combined to create alternate embodiments comprised of a combination of features which may not be explicitly described above. Features suitable for such combinations and subcombinations would be readily apparent to persons skilled in the art upon review of the present application as a whole. Any dimensions provided in the drawings are provided for illustrative purposes only and are not intended to be limiting on the scope of the invention except to the degree that such dimensions are reflected in any claims. The subject matter described herein and in the recited claims intends to cover and embrace all suitable changes in technology.