Abstract:
A fragmenting rotor assembly for comminuting waste wood and other fragmentable material. A hammer support is carried by a drive shaft driven in rotation about a longitudinal drive shaft axis. The hammer support projects radially relative to the drive shaft axis and includes a radially outer hammer head. A fragmenting knife is removably secured to the hammer head and has a reducing edge disposed in a radially outer cutting position. A deflecting member is carried by the drive shaft and has a radially outer end that deflects fragments away from at least a portion of the fragmenting knife. The hammer support and/or the deflecting member are carried by at least one rod of a plurality of circumferentially-spaced axially-extending rods that are carried on the drive shaft by axially-spaced rotor members.

Description:
[0001]    This application is a divisional application of application, Ser. No. 11/329,662 filed on Jan. 11, 2006, and claims the priority thereof, and Ser. No. 10/774,548 filed on Feb. 9, 2004 and claims the priority thereof, which is a continuation in part of application, Ser. No. 09/846,937 filed May 1, 2001 and claims the priority thereof and of provisional application Ser. No. 60/203,241 filed May 8, 2000, and also the priority of provisional application Ser. No. 60/246,862 filed Nov. 8, 2000. The application also claims the priority of provisional application Ser. No. 60/446,143 filed Feb. 10, 2003. This invention relates to rotor assemblies for heavy machinery such as hammer mills and wood hogs for fragmenting waste wood and other products, including demolition debris, stumps, pallets, large timbers, and the like into particulate or chips which are useful, for example, as mulch, groundcover, and fuel. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention is directed to improved rotor constructions of rugged and durable character. The present assignee owns U.S. Pat. No. 5,713,525, issued Feb. 3, 1998, for a typical wood hog machine and U.S. Pat. No. 5,419,502, issued May 30, 1995, for a typical tub grinder hammer mill system. Both patents are incorporated herein by reference. The rotor assemblies of the present invention are usable with either type of machine. A cutter tooth assembly for such machines is also disclosed in U.S. Pat. No. 3,642,212 (also incorporated herein by reference), issued Feb. 15, 1972, for a cutter tooth assembly for such grinders or fragmenters. 
         [0003]    Such machines, which usually comprise a rotor having a plurality of teeth that pass through openings formed in anvils or the like, and wear rapidly, must be replaced frequently. As the teeth of the rotor wear, their cutting edges become rounded or blunted and less effective in their grinding or cutting function. When in use in the field, a considerable supply of replacement cutting teeth must be maintained. 
         [0004]    The present rotor assembly is particularly constructed to overcome some of the difficulties experienced with prior art machinery and utilizes longer lived cutters. The construction in some forms also utilizes separately replaceable deflecting lobes or humps which extend radially and new methods of constructing and operating rotor assemblies. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the invention a method is provided for making a fragmenting rotor assembly operable with an anvil surface for comminuting waste wood and other fragmentable material. The method includes providing a drive shaft and mechanism for driving the shaft in a direction of rotation; supporting a plurality of rotor members in axially-spaced relationship along the drive shaft; supporting a series of circumferentially-spaced axially extending rods on and extending between the rotor members; providing a series of radially projecting hammer supports having radially outer hammer heads, the hammer supports being spaced along a rotational axis of the shaft and carried by the rods; providing fragmenting knives that each have a reducing edge, and that are removably secured to respective ones of the hammer heads such that the reducing edge of each knife is positioned in a radially outer cutting position; and supporting a plurality of deflecting members on the rods such that radially outer ends of the deflecting members are disposed in respective positions to deflect wood fragments away from at least portions of fragmenting knives carried by respective hammer heads. 
         [0006]    Alternatively, the method may include mounting separately replaceable deflecting members independently of the hammer heads and radially between pairs of hammer heads, the deflecting members having outer ends moving in circumferential paths of lesser radial extent than corresponding circumferential paths of the knife edges; the deflecting members being provided as generally oblong bodies with a central portion and with lobular outer ends, and providing the hammer heads and deflecting members in helically staggered relation along the axis of the shaft with each deflecting member lobular end in radial plane alignment with a hammer knife. 
         [0007]    Alternatively, the method may include mounting separately replaceable deflecting members independently of the hammer heads and radially between pairs of hammer heads, the deflecting members having outer ends moving in circumferential paths of lesser radial extent than corresponding circumferential paths of the knife edges; providing discs in axially spaced relationship along the drive shaft; and mounting the hammer heads angularly at the sides of the discs so that the knives thereon are of such axial extent that their paths of annular travel axially overlap without interfering. 
         [0008]    Alternatively, the method may include mounting separately replaceable deflecting members independently of the hammer heads and radially between pairs of hammer heads, the deflecting members having outer ends moving in circumferential paths of lesser radial extent than corresponding circumferential paths of the knife edges; providing discs in axially-spaced relationship along the drive shaft; and securing the knives of hammer heads disposed on opposite sides of the same disc in circumferentially displaced positions having a rotary path of axial overlap. 
         [0009]    Alternatively, the method may include mounting a deflecting member in substantially axial alignment with a hammer support and reversing the hammer support side for side when it becomes worn. 
         [0010]    Alternatively, the method may include providing discs in axially-spaced relationship along the drive shaft, mounting a series of circumferentially spaced axially extending pairs of rods to extend between the discs, and mounting the hammer heads and deflecting members releasably on the rods to extend between the pairs of rods in radially alternating relation. 
         [0011]    Alternatively, the method may include providing a fragmenting knife having two reducing edges and removably secured to the rotatively leading portions of a hammer head such that one reducing edge of the a fragmenting knife is positioned in a radially outer cutting position and the other reducing edge is positioned in a radially inner stowed position. Further according to this alternative, a deflecting member may be mounted such that a radially outer end of the a deflecting member is positioned to move in circumferential deflecting path radially beyond a circumferential path of the fragmenting knife reducing edge carried in the inner stowed position on the a hammer head and within a circumferential cutting path of the fragmenting knife reducing edge carried in the outer cutting position on the a hammer head to deflect wood fragments away from the fragmenting knife reducing edge in the inner stowed position without impeding the cutting path of the fragmenting knife reducing edge in the outer cutting position. 
         [0012]    Alternatively, the step of supporting at least one deflecting member on the drive shaft may include supporting the at least one deflecting member such that its radially outer end is disposed adjacent a radial plane of rotation of the at least one hammer support. 
         [0013]    Alternatively, the step of supporting at least one deflecting member on the drive shaft may include supporting the at least one deflecting member such that its radially outer end is disposed in the radial plane of rotation of the at least one hammer support. 
         [0014]    Alternatively, the step of supporting at least one deflecting member on the drive shaft may include supporting a plurality of deflecting members on the drive shaft in a helically staggered relationship along the shaft axis. 
         [0015]    According to the invention a fragmenting rotor assembly may be provided for comminuting waste wood and other fragmentable material. The assembly may comprise a drive shaft and mechanism for driving the drive shaft in a direction of rotation about a longitudinal drive shaft axis, a hammer support carried by the drive shaft and projecting radially relative to the drive shaft axis and including a radially outer hammer head, a fragmenting knife removably secured to the hammer head and having a reducing edge disposed in a radially outer cutting position, and a deflecting member carried by the drive shaft and having a radially outer end disposed in a position and configured to deflect fragments away from at least a portion of the fragmenting knife, at least one of the hammer support and the deflecting member being carried by at least one rod of a plurality of circumferentially-spaced axially-extending rods that are carried on the drive shaft by axially-spaced rotor members. 
         [0016]    Alternatively, the deflecting member may be disposed adjacent a radial plane of rotation of the hammer head for motion in a circumferential deflecting path radially short of a circumferential cutting path of the reducing edge of the fragmenting knife carried by the hammer head and radially beyond a circumferential path of at least a radially inner portion of the fragmenting knife extending a radial distance short of the radial distance to the fragmenting knife reducing edge. 
         [0017]    Alternatively, the fragmenting knife may have a second reducing edge and may be removably secured to the hammer head such that one of the reducing edges of the knife is positioned in a radially outer cutting position and the other reducing edge of the knife is positioned in a radially inner stowed position relative to the drive shaft axis of rotation, and the radially outer end of the deflecting member is positioned to move in a circumferential deflecting path radially beyond a circumferential path of the fragmenting knife reducing edge carried in the inner stowed position on the hammer head. 
         [0018]    Alternatively, the deflecting member may be disposed in the radial plane of rotation of the hammer head. 
         [0019]    Alternatively, the radially outer end of the deflecting member may be positioned to move in a circumferential deflecting path radially beyond a circumferential path of one or more bolts holding the fragmenting knife to the hammer head. 
         [0020]    Alternatively, the deflecting member may have a generally oblong body with a lobular outer end. 
         [0021]    Alternatively, a plurality of hammer supports and deflecting members may be carried by the rods on the drive shaft and may be driven in rotation by the drive shaft, a plurality of fragmenting knives may be removably secured to each hammer head of the plurality of hammer supports and may have respective reducing edges disposed in respective radially outer cutting positions, and the deflecting members may have radially outer ends disposed in respective positions to deflect fragments away from at least portions of respective fragmenting knives. 
         [0022]    Alternatively, the deflecting members may be supported in helically staggered positions with respect to the rotational axis of the drive shaft. 
         [0023]    Alternatively, the hammer support may be side-for-side reversible. 
         [0024]    Alternatively, the hammer support and the deflecting member may each be carried by at least one rod of the plurality of circumferentially-spaced axially-extending rods. 
         [0025]    Alternatively, the hammer support may be carried by two rods of the plurality of rods and the deflecting member may be carried by two rods of the plurality of rods, and at least one of the rods carrying the deflecting member may be disposed circumferentially adjacent and rotatively preceding at least one of the two rods carrying the deflecting member. 
         [0026]    Alternatively, both rods carrying the deflecting member may rotatively precede both rods carrying the hammer support. 
         [0027]    Alternatively, the hammer support may include two axial through-holes configured to receive two rods of the plurality of axially-extending rods. 
         [0028]    Alternatively, the deflector member may include two axial through-holes configured to receive two rods of the plurality of axially-extending rods. 
         [0029]    Alternatively, the hammer support may be carried between two axially adjacent rotor members and the deflecting member may be carried between the same two axially adjacent rotor members. 
         [0030]    Alternatively, the deflecting member may be spaced radially between the hammer support and a second hammer support may be carried between the same two axially adjacent rotor members. 
         [0031]    Alternatively, the deflecting member may be disposed adjacent a radial plane of rotation of at least one of the two hammer supports carried between the same two axially adjacent rotor members. 
         [0032]    Alternatively, at least a portion of the deflecting member may be disposed in the radial plane of rotation of at least one of the two hammer supports. 
         [0033]    Other aspects of the invention will become apparent with reference to the accompanying drawings and the accompanying descriptive matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    The presently preferred embodiment of the invention is disclosed in the following description and in the accompanying drawings, wherein: 
           [0035]      FIG. 1  is a schematic plan view of the rotor assembly; 
           [0036]      FIG. 2  is an end elevational view thereof: 
           [0037]      FIG. 3  is a schematic end elevational view of a single rotor disc only with pairs of hammers and lobes mounted thereon; 
           [0038]      FIG. 4  is a front elevational view of one of the cutter knives only prior to its coating with wear material; 
           [0039]      FIG. 5  is an end elevational view thereof; 
           [0040]      FIG. 6  is an opposite end elevational view thereof; 
           [0041]      FIG. 7  is a top plan view thereof; 
           [0042]      FIG. 8  is a schematic front elevational view of the cutter knife shown in  FIG. 4  with the wear surfaces shown as applied thereto; 
           [0043]      FIG. 9  is an end elevational view thereof; 
           [0044]      FIG. 10  is a top plan view thereof; 
           [0045]      FIG. 11  is a face elevational view of one of the lobes which mount radially between the hammers; 
           [0046]      FIG. 12  is an end elevational view thereof; 
           [0047]      FIG. 13  is a face elevational view of one of the endmost lobes; 
           [0048]      FIG. 14  is a sectional elevational view taken on the line  13 - 13  of  FIG. 13 ; 
           [0049]      FIG. 15  is an end elevational view of one of the rotor end plate deflect inserts; 
           [0050]      FIG. 16  is a cross-sectional view thereof taken on the line  16 - 16  of  FIG. 15 ; 
           [0051]      FIG. 17  is a schematic side elevational view of one of the deflect inserts which has been wear material coated; 
           [0052]      FIG. 18  is an end elevational view thereof; 
           [0053]      FIG. 19  is a fragmentary plan view of one end of the rotor shaft assembly showing the locking plate in rod locking position, certain parts of the assembly being omitted in the interests of clarify; 
           [0054]      FIG. 20  is an end elevational view thereof; 
           [0055]      FIG. 21  is an exploded reduced scale plan view of parts illustrated in  FIG. 19 ; 
           [0056]      FIG. 22  illustrates an unlocked position of the locking plate; 
           [0057]      FIG. 23  is a schematic side elevational perspective view of a modified rotor assembly, certain parts being omitted in the interests of clarity; 
           [0058]      FIG. 24  is an enlarged end elevational view; 
           [0059]      FIG. 25  is a plan view; 
           [0060]      FIG. 26  is a fragmentary end elevational view of one of the rotor disc assemblies only; 
           [0061]      FIG. 27  is a reduced size end elevational view showing deflector elements in the angular relationship in which they are used in the rotor assembly; 
           [0062]      FIG. 28  is an enlarged side elevational view illustrating another embodiment of a hammer and knife assembly; 
           [0063]      FIG. 29  is a top plan view thereof; 
           [0064]      FIG. 30  is a front elevational view; 
           [0065]      FIG. 31  is an enlarged side elevational view of the rotor body only; 
           [0066]      FIG. 32  is a front elevational view; 
           [0067]      FIG. 33  is an enlarged side elevational view of the knife employed, prior to application of its front end surface coating; 
           [0068]      FIG. 34  is a top plan view thereof; 
           [0069]      FIG. 35  is a schematic side elevational view of the knife after application of the coating to its front end; 
           [0070]      FIG. 36  is a top plan view thereof; 
           [0071]      FIG. 37  is a front end elevational view; 
           [0072]      FIG. 38  is a fragmentary perspective view; 
           [0073]      FIG. 39  is a fragmentary schematic plan view of a modified rotor assembly with hammers shown out of position to illustrate how the paths of the knives axially overlap in rotary travel; 
           [0074]      FIG. 40  is an enlarged schematic fragmenting end elevational view showing only a set of hammer heads; 
           [0075]      FIG. 41  is an enlarged side elevational view of a modified hammer head used on one side of a rotor disc; 
           [0076]      FIG. 42  is an end elevational view thereof; 
           [0077]      FIG. 43  is a view similar to  FIG. 41  of the hammer head used on the other side; 
           [0078]      FIG. 44  is an end elevational view thereof; 
           [0079]      FIG. 45  is an enlarged side elevational view of a modified spacer screening element; 
           [0080]      FIG. 46  is a schematic enlarged fragmentary plan view, showing an out of position hammer, which illustrates overlapping travel paths, in broken lines; 
           [0081]      FIG. 46A  is a similar view illustrating path overlap; 
           [0082]      FIG. 47  is a schematic diagram illustrating hammer and spacer disposition along the axial length of the rotor assembly; 
           [0083]      FIG. 48  is a fragmentary, schematic side view of a similar rotor assembly having hammers with heads which can mount knife structures on either of their front and rear faces so that when one face is worn, or there is reason to reverse a hammer head for position in a different array, it can be readily accomplished; 
           [0084]      FIG. 49  is a schematic side elevational view of one of the hammer heads with a knife mounted in one cutting position; 
           [0085]      FIG. 50  is an enlarged side elevational view of a typical end reversible hammer head; and 
           [0086]      FIG. 51  is an end elevational view thereof. 
       
    
    
     DETAILED DESCRIPTION 
       [0087]    Referring now more particularly to  FIGS. 1-47  of the accompanying drawings and in the first instance to  FIGS. 1-3 , the rotor assembly illustrated is generally designated RA and comprises a shaft  10  which may have a keyway  10   a  by means of which it is coupled to a drive motor. Typically the drive, in addition to keyway  10   a,  may comprise sprockets and chains, or sheaves and belts, coupled to a drive motor such as a diesel engine. The rotor assembly RA in all embodiments to be disclosed may be employed in any suitable wood comminuting machine such as the hammer mill disclosed in the aforementioned U.S. Pat. No. 5,419,402 or the wood hog disclosed in the aforementioned U.S. Pat. No. 5,713,525. 
         [0088]    Keyed to an enlarged portion  10   c  of the shaft  10  as, for example, at  11 , may be rotors  12   a  for axially adjacent discs or rotor plates  12  between which radially opposite hammer bodies or supports  13  may be mounted on circumferentially spaced axially extending rods R extending through opening  13   a  in the hammer bodies and  13   b  in the discs  12 . In the embodiment shown, discs or plates  12  will have six circumferentially spaced openings  13   b  to snugly slideably receive the mounting rods R.  FIGS. 19-22  illustrate the manner in which the rods R may be releasably locked in position and will later be specifically described. The hammer bodies  13  ( FIG. 3 ) include cutter mounting, radially outer head portions  14  having leading faces  14   a  extending generally radially to the direction of rotation x of the rotor shaft, and trailing faces  14   b.    
         [0089]    Fragmenting or cutting dual edge knives, generally designated  15 , to be later described in more detail, may be secured to the hammer heads  14  by a suitable fastening mechanism such as a pair of bolts  16  which extend through bolt openings  16   a  in the cutters  15  and  16   b  in the hammer heads  14  to be secured by nuts  17 . It will be noted that the hammer head sides and top or outer surfaces may be coated with bands of a wear material such as tungsten carbide  18 . 
         [0090]    Referring now more particularly to FIGS.  1  and  4 - 7 , it will be noted that the cutters, generally designated  15 , may be provided with radially outer and radially inner fragmenting or cutting edges, generally designated  19  and  20  respectively. The radially outer edges coact with the usual anvil edge A ( FIG. 1 ) to cut and fragment the material. Each of these cutting edges  19   20  may include a radially constant portion  21  ( FIG. 4 ) and a radially inclined portion  22 , but, as will be seen, the inclined portions  22  of the respective cutting edges  19 , and  20  may incline in opposing directions. Typically, the edge portion  21  ( FIG. 4 ) may be a half-inch in length when the overall axial width of the cutter is  4  inches. It will be noted that the cutter body may be counterbored as at  23  to receive the heads of bolts  16 . The angle of inclination of inclined portions  22  may typically be 12° to the surfaces  21 . 
         [0091]    As shown in  FIG. 4 , by means such as the grinding of the edges  19  a relief face  24  may be formed on the cutter body and by means such as the grinding of the edges  20  a like face  25  may be formed. The relief angle of inclination of the faces  24  and  25  may typically be 28°. It will also be seen that the end edges  21  and  20  may be relieved as at  19   a  and  20   a  and this angle of relief may typically be 8°. As  FIGS. 8-10  indicate, the cutters may also provided with a welded-on wear material that may be coated on the cutters as shown in  FIGS. 8-10  at  26 . 
         [0092]    Referring particularly to  FIG. 1 , it will be noted that the hammers on adjacent discs or rotor plates  12  may be offset angularly with respect to one another in helically staggered relation and that the edges  19  and  20  may project axially beyond the hammer head portions  14  partially across the intervening spacers  12   a.  Thus, the portions  21  of the edges  19  and  20  on axially adjacent hammer heads at their extreme axially projecting edges may revolve in closely adjacent paths of revolution, so that no appreciable space is left between these paths axially. These edges  19  and  20  on the axially adjacent cutters, which are circumferentially closest (adjacent) may be oppositely inclined as shown at a and b in  FIG. 1 . Because of this, the wood fragments are not progressively forced axially left or right and tend to remain more uniformly dispersed over the length of the cutter head assembly. It will also be observed that the cutters  15  on the axially aligned hammers  13  may have outer cutting edges that incline in opposing directions to provide a more aggressive fragmenting action. In each instance, however, there may be inner edges  20  that are basically held in reserve so that, when the time comes, the knives  15  may simply be rotated 180° once the bolts  16  are removed. The former inner edges will then become the outer “working” edges. 
         [0093]    Lobes or humps  27  of generally delta shape may be provided as shown particularly in  FIG. 3 . These lobes  27  may be situated radially between adjacent hammer bodies  13 . The inner ends of lobes  27  may be curvilinear as at  27   a  to conform to the circumference of the disc hubs  12   a.  As shown in  FIGS. 11 and 12 , rod openings  29  may be provided in the lobes  27 . The distance between a rod opening  29  and one of the openings  13   a  may be the same as the distance between the pair of openings  13   a  in each hammer  13  so that rods R, mounted or supported by discs or plates  12 , may mount both the hammers and the lobes in radial alignment, as  FIG. 2  indicates. 
         [0094]    The interior lobes  27  may be configured as shown in  FIGS. 11 and 12 . The endmost lobes, at each end of the rotor assembly, are designated  30 , and likewise may have openings  29  to receive and pass the mounting rods R. They also, however, may be provided with openings ( FIGS. 13 and 14 ) comprising bores  32  and counterbores  33 . Provided to be received in the openings may be screening or deflecting inserts, generally designated  35  (see  FIGS. 15 through 18 ), which comprise square shaped bodies  35 a that may have wear surface-coated sides  36  as shown. The bodies  35  may have cylindrical portions  35 b that are received in one of the openings  33  and can be secured by screws extending from the opposing opening  33  and threaded into bolt openings  38  in inserts  35 . 
         [0095]    As  FIG. 1  particularly points out, the purpose of the inserts  35  may be to project axially across the rod-locking end plate assemblies generally designated EP and furnish wear material coated surfaces for engaging the work and radially protecting or screening the end plate assemblies EP. 
         [0096]    Referring now to  FIGS. 19-22 , each end plate assembly EP may include an end plate  39  having an outwardly facing cavity or recess  40  in which a locking plate or ring disk  41  may be received for limited rotary adjustment. The end plates  39  may have bores  42  for passing rods R and locking plates  41  having identically circumferentially spaced bores  43  which in the rod-releasing position ( FIG. 22 ) can be aligned with bores  42 .  FIG. 20  illustrates a rod-locking position in which the locking plates  41  have been rotated slightly to block endwise removal of the rods R. Circumferentially spaced bolts  44  projecting endwisely through end plates  39  may also pass through arcuate slots  45  and may have nuts to fix the rotary adjustment of the locking plates  41 . It will be seen that the ends of shaft  10  may have threaded portions  46  that releasably receive lock nuts  47  for fixing the plates  39  in locked position. 
         [0097]    In operation, the assembled rotor assemblies may be provided in either a wood hog or a hammer mill, such as a tub grinder hammer mill, for example, and driven in the direction of rotation x. When the outer radial edges  19  of the cutters  15  require resharpening, the bolts  16  may be removed and the cutters  15  turned end-for-end to dispose the former inner edges  20  radially outwardly. Obviously, other cutters  15  may be carried in inventory so that the need for trips to the cutter resharpening station can be minimized. The cutting edges  19 , which are outermost and may incline in opposite directions on radially in-line hammer heads  14 , provide an aggressive cut in a fragmenting operation. With the provision of portions  21 , however, there are no points to be readily worn or rounded, as may be the case if the edges  22  were to extend from end-to-end of the cutters  15 . 
         [0098]    The paths of rotation of the outer knife cutting edges are shown at “y” in  FIG. 3 . The paths of the outer edges of the lobes or deflectors  27  are shown at “z”. It is to be noted that the outer edges of lobes  27  traveling in the paths “z” radially protect the inner edges  20  of each cutter knife  15  during operation, along with also protecting or screening the bolts  16  that hold the cutters  15  in respective fixed positions. Because of the disposition of lobes  27  in or adjacent the radial planes of the knives, wood fragments which might otherwise impinge upon the inner edges  20  and the bolts  16 , are deflected in substantial part by the deflector lobes  27 . 
         [0099]    A further assembly, which is modified in several respects, is disclosed in  FIGS. 23-27 . Where the parts or assemblies are generally the same as previously described, the same numerals and letters have been used to designate them. 
         [0100]    In  FIG. 25 , for example, the overall rotor assembly is similar to the rotor assembly RA disclosed in  FIG. 1 , and the hammer assemblies  13  are identical. The rotor assembly RA may operate in conjunction with an anvil A of the character disclosed in  FIG. 1 , and rods R, as previously, may be used to mount the hammer bodies  13  and associated knives  15  in assembled position. The hammer body openings  13   a  may, as previously, be provided along a circle “c” having a constant radius taken from the axis of shaft  10 . In the rotor assembly of  FIGS. 23-27 , however, there are no rotor plates  12  and, as  FIG. 25  indicates, the fragmenting and cutting edges  19  and  20 , which may be provided on hammer heads  13 , may project axially beyond the hammerhead portions  14  to partially axially lap one another. The edges  19  and  20  on the axially adjacent cutters, which are circumferentially closest (adjacent), may not be inclined. The cutter head assembly RA, as previously, may include the rod-locking end plate assemblies EP, including end plates  39  that mount the ends of rod R and the locking plates  41  that lock the removable rods R in position. 
         [0101]    In the prior described rotor assembly, the lobes or humps  27  of generally delta-shape may have curvilinear surfaces  27   a  that may be received by the disc hubs  12   a.  In the present case, the delta-shaped lobes may be replaced by dual deflector lobe members, generally designated  48 , having keyways  49  or  53 , which may secure them on the shaft  10  by way of appropriate keys. Rods R may similarly extend through the openings  50  that may be provided in  180 ° spaced apart relation along circle “c” in the members  48 . It will be noted that the members or deflectors  48  may be shaped such as to provide curvilinear surfaces  51  that match the curvilinear surfaces  13   b  of the hammer bodies  13  on which they are received, and that the screening members  48  may also provided with radially outer lobes  52  having outer peripheral deflecting surfaces  52   a.  The deflector lobe members  48  may have generally the same axial width as the hammer bodies  13  and it will be noted that the peripheral surfaces  52   a  may have the path of rotation previously identified by the letter “z” in  FIG. 3  and may radially protect the inner edges  20  of each cutter  15  during operation, along with also protecting or screening the bolts  16  that hold the cutters  15  in fixed position. 
         [0102]      FIG. 27  illustrates a staggered relationship of axially successive deflector lobe members  48 . It will be noted that the parts  48  may be identical, with the exception that the horizontal disposed member or element  48  at the right end of  FIG. 27  may differ in the configuration of its keyways  29  from the keyway shapes  53  shown in  FIG. 27 , which, may require axially extending keys of the same configuration to mount them on the shaft portions  10   c.    
         [0103]    In operation, the cutter head assembly, disclosed in  FIGS. 23-27 , may also be used in either a wood hog or a hammermill and the hammer bodies may operate in the same manner as previously described. With the circumferential path of rotation of the surfaces  52   a,  wood fragments that would otherwise impinge upon the inner edges  20  and/or the bolts  16  are deflected in substantial part by the dual deflector lobe members  48 . 
         [0104]      FIGS. 28-37  are directed to another hammer knife assembly in which, again, like parts have been identified by the same numerals and letters as previously. In this construction, the front or leading face of each hammer head  14 , generally designated  54 , may be formed with a radially inwardly inclined support surface  55  ( FIG. 31 ) which, for example, can extend at an angle of 125° to the vertical in this figure. A tool base supporting surface  56  leads from surface  55  and can extend at 90° to the surface  55  in  FIG. 31 . The recessed configuration  54  may also include a vertical surface  57  as shown in  FIG. 31 , and a clamping surface  58  which, for example, can extend at 128° to the surface  57 . 
         [0105]    As  FIG. 28  illustrates, it is the surfaces  55  and  56  that may receive the fragmenting or cutting tool, generally designated T, which is provided with a hard surfaced coating  59  for cutting tool edge  60 .  FIGS. 33 and 34  illustrate the configuration of the cutting tool T prior to coating, which is shown as a tool bar in  FIGS. 33 and 34  which is cut away at an angle of, for example, 45° from its upper surface  61  as at  60   a  to define the uncoated cutting edge  60 . It will be noted that the upper surface  61  of tool bar T may be recessed as at  62  at an inclined relief angle of about, for example, 3° from the surface  61  and that the base end wall  63  at its upper end may be relieved as at  64 . 
         [0106]    The hard tungsten carbide, or other suitable hard surfaced material, which may be applied to the face  60   a  and cutting edge  60 , as shown in  FIGS. 35-38 , may be about one-eighth inch in thickness. As shown in  FIG. 35 , the material may coat a major portion of wall surface  60   a  and the front end of bottom surface  66  to protrude from each. The material, likewise, as shown in  FIGS. 36 and 37  may project laterally beyond the side walls  65  of the tool bar as at  65   a.  It is the flat outer surface  66  of the toolbar, which may be engaged by the wedge plate  67  (shown in  FIGS. 28 and 30 ). Plate  67  may have oppositely disposed, similarly inclined wedging surfaces  68  and  69 , which may respectively engage the toolbar face  66  and the hammer head surface  69  to wedge the toolbar T in rigidly fixed position. A threaded opening  70 , which may be provided in wedge plate  67 , aligns with a bolt opening  71  through head  14  to receive a bolt  72  which, when revolved in one direction, draws the plate  67  inwardly to tightly clamp toolbar T in position. 
         [0107]    In operation, the toolbar T aggressively attacks the wood debris being fragmented or reduced as the rotor assembly RA is revolved at a rapid rate of speed. By loosening bolt  72  and rotating it in the opposite direction, wedge plate  67  may be backed off to permit the ready substitution of a replacement tool T, when wear makes substitution necessary. 
         [0108]      FIGS. 39-47  illustrate a still further modified rotor assembly. Where the parts or assemblies are generally the same as previously shown and described, the same numerals and letters have been used to designate them. As before, the rotor assembly RA operates in conjunction with an anvil (not shown). Its drive shaft  10  is shown as journaled in frame supported bearings B supported by machine frame F, and as being driven by a sheave element, generally designated SH, which may be configured to receive motor drive belts in the usual manner. While not previously shown in the drawings, it is to be understood that all of the rotor assemblies shown herein may be journaled and driven in the manner disclosed in  FIG. 39 . 
         [0109]    Fixed in axially spaced relationship along the shaft  10  may be a series of rod-supporting rotor members which may take the form of discs, for example, and which are generally designated  72 . As  FIG. 40  indicates, the hammer supports or legs  14  may be provided in 180° spaced relation axially adjacent each of the discs  72 , on the rods R, which are replaceably mounted as previously disclosed. In the present instance, however, there may be a total of 8 rods disposed in 45° apart circumferential relationship. The rods R may be locked in position by the elements disclosed in  FIGS. 19-22 . 
         [0110]    The hammer supports or bodies  14  and knife structures  15  may be of the same constructions as previously set forth in any of the drawing figures with the salient difference in this embodiment, however, that the head portions  14  may tilt forwardly with respect to a radial line rl extending from the axis of rotation “r”, in the direction of rotation of the outer knife edge  19 . This forward tilt can be readily ascertained by comparing the radial line rl shown in  FIG. 40  with the like radial line rl shown in  FIG. 41 .  FIGS. 41 and 43  particularly illustrate this configuration wherein the head portions  14  of the hammers may extend at an angle with respect to the hammer body portions  13 . It has been found that with the hammer head in effect tilting forwardly as disclosed a more aggressive bite is obtained by the tilted knife edges. With respect to the hammer heads disclosed in  FIGS. 41 and 43 , it is to be noted that the body portions  13  may include curvilinear shoulders  73  offset an amount 0 to mate with the periphery of discs  72  and that the angle of inclination of the leading face  74  of each of the heads  14  of the modified embodiment may extend at an angle of approximately 7° to the radial line rl. Otherwise, the hammer heads may remain effectively the same as those disclosed in the first embodiment of the invention. 
         [0111]    In  FIG. 45 , a modified form of deflector element or member is disclosed generally at  74 . The element  74  may be referred to as generally chain-link configured, and may include openings  75  permitting its mounting on a pair of the circumferentially adjacent rods R in the axial spaces between rotor discs  72  in radial alignment with hammer legs mounted radially outwardly of the discs  72  on rods R. Element or member  74  may also include arcuate surfaces  76  for enabling it to clear the shaft  10 . One of the members  74  is shown schematically in position in  FIG. 39 . It is to be appreciated that each of the pairs or sets of hammers, which are essentially of any of the configurations described herein, may be disposed 180° apart in the spaces between discs  72  as shown and may be successively helically staggered axially. Thus, the position of the respective hammers shown in  FIGS. 39 ,  46 , and  46 A, in which true axial knife overlap is indicated, may never be reached. These figures are included to illustrate knife path overlap. 
         [0112]    In  FIGS. 39 ,  46 , and  46 A, the rotor members involved in these figures have been designated as  72   a  and  72   b.  The hammer supports involved have been designated as  13 A,  13 B, and  13 C. It will be assumed that in  FIG. 46A , only the hammer support  13 A is shown in its true position. Hammer support  13 B is shown in a broken line position and, of course, would truly be circumferentially displaced from hammer body  13 A. However, by showing hammer body or support  13 B in a rotated position, it is possible to show the three quarter inch axial path overlap that may be achieved. 
         [0113]    With particular attention now to  FIG. 46  and with the hammer support  13 A again being shown in its true position, it is possible to show that when hammer support  13 A is in true position, and hammer support  13 C is rotated out of true position to the broken line position in  FIG. 46 , an axial path overlap of a quarter of an inch is achieved. This means that the entire axial surface of the work may be covered during rotation of the knives, which, along the axis r of the rotor assembly, have paths of rotation that may be entirely axially overlapping, while being displaced circumferentially with respect to one another. The overlap may be created by shouldering or insetting the hammer bodies at  73  an amount 0 on one side of the hammer bodies to achieve the overlap desired. 
         [0114]    The diagram,  FIG. 47 , illustrating a further arrangement discloses the various rods or support members designated  1 - 8  at the left end and illustrates these positions in clockwisely arranged vertical position in the hammer-spacer designation part of the diagram. The hammers of  FIGS. 46 and 46A  are indicated by the letters X and the deflector members  74  termed spacers by the letters O on the diagram, and the disposition of the members  74  and hammers is well indicated in the spaces g between rotor members or the disc or plate representations  72 . As will be seen, there may be a deflector member spacer  74  indicated at O for each hammer X and such spacers may be arranged as indicated in the axial spaces g between the rotor discs or spacers  72 , which are numbered 1-18. The disposition of the hammers and deflectors  74  circumferentially is portrayed in the diagram. In this embodiment the hammers are not in true radial alignment in the gaps or spaces g. 
         [0115]    In operation, the offset tilted hammer heads  14  may operate as previously but may take a more aggressive bite and the cutting edges may have an overlapping path of travel. 
         [0116]    In  FIGS. 50 and 51 , a modified hammer support is disclosed, which may include the same body portion as shown in  FIGS. 43 and 44  with the inset or recessed shoulder portion  73 . The present hammer support may differ from the forwardly tilted hammer head  14  disclosed in  FIGS. 43 and 44  in that it may be symmetric on each side of its center line rl, which is a radial line generally bisecting the axis of shaft  10 . In this case, the same pair of rod openings  16   a  may be provided in the hammer support head  14  and the leading and trailing faces  1  and t may be parallel to one another, and parallel to line rl. With this configuration, the knife structure or hammer, generally designated previously as  15 , may be mounted on either the face  1  or, if the hammer support is axially reversed, on the face t. 
         [0117]    In  FIG. 48 , each disc or rotor  72  is shown as carrying a pair of hammer supports including an upper hammer support  13  on one side of a disc  72  and a similarly disposed lower hammer support  13  on the opposite side of the disc  72 , 180° apart. The deflector members or plates  74  may be provided axially between each hammer support  13  and the adjacent disc or rotor  72 , and may also function to hold each hammer support away from the rotor disc  72  it is not to rest against. At the ends of the rotor assembly, it will be noticed that hammer supports  13  may be provided which rest on each end plate assembly, generally designated EP, with the construction disclosed in  FIGS. 48 and 49 . The hammer supports  13  may be 180° reversible on the rods R, and when their leading faces are worn or damaged, the hammer supports may be reversed in the sense that formerly trailing faces t become the leading faces and the formerly leading faces  1  become the trailing faces. On any one rotor disc, the disposition of the hammer supports may simply be reversed with respect to the disc  72 . For example, considering  FIG. 48 , the upper hammer supports would then be mounted on the rods R to abut the opposite sides of the disc  72  on which they are shown mounted in  FIG. 48  and the lower hammer supports  44  simply reversed to mount on the opposite side of the discs  72  on which they are shown in  FIG. 48 . Also, the position of the reversible plates  74  may be changed to accommodate the new position of the hammer supports and hammers that are driven in rotation by rods R, end plates EP and shaft  10 . In  FIG. 48 , the hammer supports are shown at h in reversed position. While in  FIG. 48 , only one pair of the hammer supports is shown in 180° spaced relationship, it is to be understood that they may be used in many other desired relationships. For example, in  FIG. 49 , the rods R are so disposed that two pairs of knives may be provided and the pairs may be disposed in an axially staggered or helical array, as disclosed in previous embodiments in a manner to preserve dynamic balance. 
         [0118]    The disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive thereof. The invention is defined in the claims.