Abstract:
The present invention relates to a single shaft rotary grinder having a modular and/or split apart configuration. The modular configuration has assembly units and/or component parts that are interchangeable providing ease of construction of a rotary grinder having desired functionality for a specific application and/or providing ease of maintenance with the ability to replace worn or broken assembly units or component parts. The split apart configuration provides for the separation of a rear power head assembly and a front feeder assembly allowing easy access to the rotor and rear inner portion of the feed assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A “SEQUENTIAL LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISC 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a rotary grinder with an improved modular and/or split apart design. 
     2. Description of the Related Art 
     Rotary grinders with forced horizontal feed are known. Typically, they are designed to have a ram compartment with a lower compartment plate serving as a lower portion of a hopper of the grinder. A reciprocating ram, typically horizontally driven by a hydraulic piston system, has a vertically situated ram slidingly resting on the horizontally situated lower compartment plate and forces material from the hopper to a rear power head having a rotor with teeth for reducing the material in the hopper. Other feed systems such as roller feeder systems have been used wherein the material is fed to the rotor between a pair of opposing rollers. 
     Typically, the rotary grinders of the prior art are of a unitary structure wherein sidewalls of the grinder extend from the front compartment to the rear power head. Such a configuration makes it difficult or impossible to custom assemble a rotary grinder having a selected front compartment with a selected rear power head or to change the configuration of the rotary grinder once having been manufactured. Additionally, these unitary rotary grinders have lacked modular components and assemblies that can be replaced with the same or different components for maintenance or reconfiguration of the rotary grinder. Furthermore, the unitary configuration of the prior art rotary grinders makes it difficult to access parts and components for maintenance, repair, or replacement such as replacing teeth on the rotor or adjusting a counter knife. 
     SUMMARY OF THE INVENTION 
     Rotary grinders of embodiments of the present invention are, for example, used to grind plastic, carpet, wood or other solid materials to reduce the size of the material to a desired size. The rotary grinder may also be used to reduce material such as film, fibrous material and other materials which have a tendency to wrap around the rotor. The materials to be shredded are placed into a hopper or other feeding mechanism such as opposed cylindrical rollers. In an embodiment having a hopper, a reciprocating ram is used to drive the material toward a counter knife horizontally situated with the longitudinal axis of the rotor. The rotor has a plurality of cutters removably mounted thereon. When in use, the ram travels from its open position near the front end of the rotary grinder across the hopper floor or lower compartment plate towards the rotor, pushing material towards the rotor and counter knife. As the rotor revolves about its axial shaft, the cutters on the rotor engage the material in the hopper drawing the material downward towards the counter knife. The counter knife has a cutting edge with interstices that closely receive the cutters on the rotor. The material is cut into pieces between the cutters and the counter knife. 
     Embodiments of the present invention for a rotary grinder have an improved modular and/or split apart configuration. The modular configuration has a separate front compartment assembly and rear power head assembly. The front compartment assembly has modular components such as a ram assembly, component sidewalls, and a support frame assembly. Other optional components include a hydraulic system for separating the front compartment assembly from the rear power head assembly and electronic sensors and control component assemblies. The rear power head assembly has modular components such as a rear power head frame supporting a modular right and left power head wall, an anvil, a rotor, a gear box, and a motor. Each of these component parts may have subcomponents and may be removed and replaced with the same or different component, subcomponent, or assembly making the modular rotary grinder transformable for different grinding needs or serviceable by the replacement of component parts. 
     In a split apart configuration, a front compartment assembly has a front compartment and a ram assembly where the front compartment is defined by a lower compartment plate and upward extending compartment sidewalls proximate each longitudinal edge of the lower compartment plate. The compartment plate and sidewalls are supported with a modularized front compartment frame. A ram assembly has a vertically oriented ram with a lower edge proximate the horizontally situated compartment plate and side edges proximate each sidewall. Each compartment sidewall has a front mating edge for engagement with rear mating edges on sidewalls of a rear power head assembly. An anvil extends between the lower end of the rear mating edges of the power head assembly sidewalls and is engageable with the lower compartment plate. Engagement of the mating edges and the anvil with the lower compartment plate forms a compartment having a rotor in a rear portion thereof and disengagement of the mating edges and anvil from the lower compartment plate provides for working space between the rear power head assembly and the front compartment assembly. A retainer assembly has a portion on the front compartment assembly and a portion on the rear power head assembly for removably retaining the front compartment assembly with the rear power head assembly. 
     The front compartment can be slidingly engageable with the rear power head assembly or the front compartment may be hingedly cooperable at a front of the compartment plate enabling the rear of the compartment plate to swing upwardly providing a working space between the rear power head assembly and the front compartment assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the invention will be had upon reference to the following description in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a modular rotary grinder having a slide apart design showing a rear power assembly and a front compartment assembly having a hopper partially removed and a ram in retracted position; 
         FIG. 2  is a perspective view of the modular rotary grinder of  FIG. 1  having the front compartment assembly slid apart from the rear power assembly; 
         FIG. 3  is a perspective view of the modular rotary grinder of  FIG. 1  having the front compartment assembly slid apart from the power assembly showing a compartment assembly end of a retainer assembly for removably retaining the front compartment assembly to the rear power assembly; 
         FIG. 3A  is a cut-away view of the modular rotary grinder of  FIG. 3  showing the front compartment assembly end of a retainer assembly; 
         FIG. 4  is a perspective view of the modular rotary grinder of  FIG. 1  having the front compartment assembly slid apart from the power assembly showing a rear power head end of a retainer assembly for removably retaining the front compartment assembly to the rear power assembly; 
         FIG. 4A  is a cut-away view of the modular rotary grinder of  FIG. 4  showing the rear power head assembly end of a retainer assembly; 
         FIG. 5  is a rear lower perspective view showing the modular rotary grinder of  FIG. 1 ; 
         FIG. 5A  is a cut-away from  FIG. 5  showing the components of a grinder control system; 
         FIG. 5B  is a rear lower cutaway view of a portion of the compartment assembly and frame showing an embodiment of a slidingly engagement therebetween; 
         FIG. 6  is a perspective view of a rear power head assembly showing rear mating edges and a rear bumper plate; 
         FIG. 7  is a perspective view of a front compartment assembly showing front mating edges and a front bumper plate; 
         FIG. 7A  is a cut-away from  FIG. 7  showing a portion of a retainer assembly; 
         FIG. 8  is a cutaway perspective view of a rear power head assembly and a front compartment assembly showing internal components thereof; and 
         FIG. 9  is a perspective view of an embodiment of the modular grinder having a front hinged compartment assembly. 
     
    
    
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiments in many different forms, there are shown in the Figures and will herein be described in detail, embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention, and is not intended to limit the broad aspects of the invention to the embodiments illustrated. 
     With reference to  FIG. 1 , modular single shaft rotary grinder  100  is shown having a rear power head assembly  103  and front compartment assembly  102  matingly engaged. Rear power head assembly  103  comprises power head frame  116  supporting modular component parts of power head assembly  103 . Component parts of power head assembly  103  include motor  152  attached to a lower part of housing assembly  116  and in mechanical cooperation with gear box  146 . Gear box  146  is also in mechanical cooperation with rotor  106  and transfers power from motor  152  to rotor  106 . Right lower power head wall  105  and left lower power head wall  107  each have an aperture for receiving an axial end of rotor  106 . In this embodiment, right and left power head walls  105  and  107  have a vertical opening above the axial ends of rotor covered with plate  171 . Plate  171  is removable permitting the vertical removal of rotor  106  with left and right power head walls  105  and  107  attached to power head frame  116 . Right power head walls  105  and  107  have a rear mating edge  142 . Moveable anvil  136  (shown in  FIG. 3A ) movably extends between right and left lower power head walls  105  and  107  proximate a front lower portion of rotor  106 . Counter knife  109  moveably attaches to a top surface of anvil  136  and has a contoured blade adjacent rotor  106  closely receiving cutters  131  removably extending from an outer cylindrical surface of rotor  106  as rotor  106  rotates. Upper rear wall  108  is joined with and situated between upper right wall  113  and upper left wall  111  forming a rear portion of a hopper. Upper rear wall  108  is shown in this embodiment as sloping, but may be vertical. 
     Front compartment assembly  102  has front compartment  114  and a ram assembly ( 115 ,  FIG. 5 ) supported by modular front compartment frame  101  having a plurality of compartment supporting legs  104  extending between two longitudinally extending supporting beams. Front compartment  114  is defined by lower compartment plate  112  and an upward extending lower sidewall  118  proximate each longitudinal edge of lower compartment plate  112 . Lower compartment plate  112  has compartment plate lip  134  extending over movable anvil  136 . Lower sidewalls  118  each have a front mating edge  140 . Atop a rear modular section of each lower sidewall  118  extends an upper side wall  121 . Upper hopper assembly  110  is shown removed from upper sidewall  121 . When upper hopper assembly  110  is removably fastened to upper sidewalls  121 , a hopper is formed extending over front compartment plate  112  and rotor  106 . Upper right wall  113 , upper left wall  111 , and upper rear wall  108  form a rear section of the hopper over the rotor. Ram assembly  115  is covered with compartment top cover  128  and ram  119  (shown in  FIG. 5 ) has compartment rear wall  123  extending upward therefrom when ram  119  is in a retracted position as is shown in  FIG. 1 . Ram slide rail  124  longitudinally extends between each lower side wall  118  and upper sidewall  121  wherein an outwardly depending portion of ram  119  slides when ram  119  is longitudinally pushed or pulled to or from rear power head assembly  103  with a ram hydraulic system having ram hydraulic cylinder  138 . Preferably ram slide rails  124  have a polymeric lining reducing friction within ram assembly  115 . Lower side walls  118  modularly extend to the front of front compartment assembly  102  and have an outwardly extending flange  126  slidingly engaging compartment slide rails  127 . Outwardly extending flanges  126  and compartment slide rails  127  enable front compartment assembly  102  to be slidingly separated from rear power head assembly  103 . Preferably, the power to slide front compartment assembly  102  to and from rear power head assembly  103  is hydraulically supplied by an independent hydraulic system. 
     With reference to  FIG. 2 , single shaft rotary grinder  100  is shown having a rear power head assembly  103  and front compartment assembly  102  in a split apart configuration. Rear power head assembly  103  comprises power head frame  116  supporting component parts of power head assembly  103 . Front compartment assembly  102  has front compartment  114  and a ram assembly  115  ( FIG. 5 ) supported by modular front compartment frame  101 . In this split apart configuration, worker  129  is availed space to enter between front compartment assembly  102  and rear power head assembly  103  to perform maintenance operations without the need to empty front compartment  114  of materials being ground. In this embodiment, front compartment assembly  102  slides apart from rear power head assembly  103  on modular front compartment frame  101 . The slide apart feature is provided with lower outwardly extending flange  126  extending outwardly from each lower longitudinal edge of front compartment assembly  102  slidingly engaging a compartment slide rail  127 . Preferably, surfaces of compartment slide rail  127  slidingly engaging flanges  126  are comprised of a polymeric material reducing the friction between front compartment assembly  102  and modular front compartment frame  101  when sliding front compartment assembly fore and aft of modular front compartment frame  101 . In this slide or split apart configuration, rear mating edges  142  and front mating edges  140  are separated and compartment plate lip  134  is removed from a top surface of anvil  136 . Cylindrical hydraulic ram  138  provides the force necessary to slide front compartment assembly  102  fore and aft of modular front compartment frame  101 . 
     In the split apart configuration as shown in  FIG. 2 , worker  129  has easy access to modular components of power head assembly  103  and compartment assembly  102  for maintenance and/or replacement. For instance, rotor  106  may be cleared of debris, cutters on rotor  106  may be serviced or replaced, anvil  136  may be adjusted, and counter knife  109  may be replaced, serviced, or adjusted without the need to clear front compartment  114  of debris or disassemble portions of rotary grinder  100  to gain access to component parts. Additionally, access to modular parts such as motor  152  and gear box  146  is increased. In this view, removable belt  175  is shown cooperating with motor  152  and gear box  146  wherein motor  152  and gear box  146  are mounted to power head frame  103  in a parallel configuration. However, it is to be understood that motor  152  and gear box  146  may be in a right angle mount, have a fluid coupling and/or have a controlled torque coupling. The optional fluid coupling provides for a soft start while the controlled torque coupling protects against over torque as may be experienced with a rotor lock. 
       FIG. 3  shows modular rotary grinder  100  in a split apart configuration with a retainer assembly shown in detail in  FIG. 3A . Rotary grinder  100  comprises rear power head assembly  103  having a power head frame  116  supporting a right lower power head wall  105 , a left lower power head wall  107 , an anvil  136 , a rotor  106 , a gear box  146  (shown in  FIG. 1 ), and a motor  152  (shown in  FIG. 1 ). Right lower power head wall  105  and left lower power head wall  107  each extend upward from power head frame  116  about each axial end of rotor  106  and have a rear mating edge  142 , anvil  136  movably extends between right and left lower power head walls  105  and  107  proximate a front lower portion of rotor  106  and has counter knife  109  moveably engaged on an upper surface thereof. Counter knife  109  may be adjusted closer to rotor  106  maintaining a close tolerance between cutters  131  and a cutting edge on counter knife  109 . Additionally, in the embodiment shown, counter knife  109  may be serviced or removed, rotated, and reinstalled onto anvil  136  placing an opposite cutting edge of counter knife  109  adjacent cutters  131 . This can be accomplished manually in the split apart configuration without the need to enter the hopper or compartment  114 . 
     Front compartment assembly  102  having front compartment  114  and ram assembly  115  where front compartment  114  is defined by lower compartment plate  112  and an upward extending lower compartment sidewall  118  proximate each longitudinal edge of lower compartment plate  112 . Front compartment assembly  102  is supported with a front compartment frame having supporting beams  117  interposed with supporting legs  104 . Lower compartment sidewalls  118  each have a front mating edge  140  that matingly engage a rear mating edge  142  on rear power head assembly  103 . Anvil  136  and lower compartment plate  112  are shown as being slidingly disengaged. Engagement of mating edges  140  and  142  and anvil  136  with lower compartment plate  112  forms compartment  114  having rotor  106  in a rear portion thereof and sliding disengagement of mating edges  140  and  142  and disengagement of anvil  136  from lower compartment plate lip  134  provides for working space between rear power head assembly  103  and front compartment assembly  102 . A retainer assembly  137  is shown in  FIG. 3A  has a portion on front compartment assembly  102  and a portion on rear power head assembly  103 . Each portion of the retainer assembly  137  is cooperable with the other portion enabling front compartment assembly  102  and rear power head assembly  103  to be securely engaged wherein front and front mating edges  142  and  140  are mated and anvil  136  is mated with compartment plate  112 . The portion of the retainer assembly  137  on front compartment assembly  102  may be a clamp rod sleeve  133  or a clamp rod fastener retainer  130  on an upper portion of each side of power head frame assembly  116  where front compartment assembly  102  has the other of clamp rod sleeve  133  or clamp rod fastener retainer  130  proximate each rear outer corner of compartment plate  112 . Clamp rod  132  extends through clamp rod sleeve  133  into clamp rod fastener retainer  130  and removably cooperates with fastener  135  removably retained in fastener retainer  130 . In the embodiment shown here, clamp rod  132  is a threaded bolt and fastener  135  is a nut threadingly engageable with threaded bolt  132 . Fastener retainer  130  may have a threaded portion therein eliminating the need for threaded bolt  132 . Also shown in  FIG. 3A  is compartment bumper plate  122  centrally depending from a lower side of compartment plate  112  which engages power head bumper plate  120  (shown in  FIG. 5 ) centrally oriented on a front portion of power head frame  116 . Compartment bumper plate  122  engages power head bumper plate  120  when retainer assembly  137  securely engaged. Shown in  FIG. 3  is optional horizontal plate  153  outwardly extending under bumper plate  122  wherein a top surface engages a lower surface of power head bumper plate  120  or other vertically supporting member on power head frame  116 . Also shown here is outer fixed seal ring  179  and inner rotating seal ring  181  having a close tolerance therebetween. Having inner rotating seal ring  181  with a larger diameter than rotor  106  substantially decreases or even eliminates materials being ground from lodging between axial ends of rotor  106  and sidewalls  105  and  107 . Pillow block bearing  177  is shown supporting an axial end of rotor  106  on power head frame  116 , however, any bearing or other friction reducing engaging means as is known in the art may support axial ends of rotor  106 . Preferably, pillow block bearing  177  is horizontally separable wherein a top portion can be removed allowing rotor  106  to be vertically removed. 
       FIGS. 4 and 4A  show retainer assembly  137  having a portion on front compartment assembly  102  and a portion on rear power head assembly  103 . The portion of the retainer assembly  137  on power head frame assembly  116  has clamp rod sleeve  133 . Clamp rod  132  is in the form of a threaded bolt having the head of clamp rod  132  adjacent clamp rod sleeve  133 . 
     It is important to note that the fastening combination of retainer assembly  137  may be in a reverse orientation and still provide the function of fastening front compartment assembly  102  with rear power assembly  103  joining front mating edges  140  with rear mating edges  142  and compartment bumper plate  122  with power head bumper plate  120 . Additionally, other removable fastening combinations as is known in the art may be used to removably secure front compartment assembly  102  to rear power assembly  103 . An alternative embodiment of a power head wall is shown here wherein right and/or left power head walls are modular having an upper power head wall component  173  and a lower power head wall component  175 . The separation of upper power head wall component  173  and lower power head wall component  175  provides for the vertical removal of rotor  106 . 
       FIG. 5  shows a bottom perspective view of modular grinder  100 . In this view, rear power head bumper plate  120  is in an aligning relationship with front compartment bumper plate  122 . When front compartment assembly  102  and rear power assembly  103  are in an engaged position with front mating edges  140  mated with rear mating edges  142 , rear power head bumper plate  120  and front compartment bumper plate  122  become engaged. Therefore, rear power assembly  103  and front compartment assembly  102  are held together in a stable linear relationship with the central engagement of retainer assembly  137 , upper engagement of front mating edges  140  with rear mating edges  142 , and lower engagement of power head bumper plate  120  with front compartment bumper plate  122 . Also shown in this figure and detailed in  FIG. 5  A are components of an embodiment of a grinder control mechanism having a ram position sensor rail  158  with slots  160 . Ram position sensor rail  158  is attached to ram assembly  115  having ram  119  on a rear end thereof and moves fore and aft of front compartment assembly  102  pushing materials toward rotor  106 . Sensor  156  and ram position sensor rail bracket  150  are mounted atop ram position sensor mount  148  and senses the position of ram sensor rail  158  via slots  160  and sends a signal through cable  154  to an external electronic control system (not shown). Ram assembly  115  has ram  19  vertically oriented and extending between lower compartment sidewalls  118  and up from lower compartment plate  112 . Ram sensor rail  158  is attached to ram assembly  115  and moves therewith, therefore ram sensor  156  senses the position of ram  119 . Other embodiments of a grinder control mechanism include laser or sonar sensor mechanisms having limit, velocity, and position controls. 
       FIG. 5B  shows an alternative embodiment of elements for slidingly cooperation between front compartment assembly  102  and modular front compartment frame  101 . Supporting leg  104  supports supporting beams  117 . Supporting beams  117  support notched slide  162 , preferably comprised of a polymeric material. Outwardly extending flange  126  has longitudinally extending upper slide  159  with longitudinally extending guide  161  attached to a lower surface thereof. Preferably, upper slide  159  and guide  161  are comprised of a metallic material slidingly engaging notched slide  162 . Also shown here is an optional lateral support feature comprising guide  155  and guide retainer  157 . Guide  155  longitudinally extends supporting beam  117  and has an outwardly extending upper end. Guide retainer  157  longitudinally extends and is attached to flange  126  and extends around guide  155  providing slidingly lateral support between front compartment assembly  102  and front compartment frame  101 . 
       FIG. 6  is a perspective view of rear power head assembly  600  showing rear mating edges  142  and power head bumper plate  120 . Rear power head assembly  600  comprises power head frame  116  supporting modular component parts of power head assembly  600 . Right lower power head wall  105  and left lower power head wall  107  are each about an axial end of rotor  106  and have a rear mating edge  142 . Preferably, left and right lower power head walls  105  and  107  each have removable modular upper half or a slot in an upper half allowing for the vertical removal of rotor  106  without the removal of power head walls  105  and  107 . Rotor  106  is shown here as having tool holders  143  extending from an outer cylindrical surface thereof for supporting cutters thereon. Moveable anvil  136  movably extends between right and left lower power head walls  105  and  107  proximate a front lower portion of rotor  106 . Counter knife  109  moveably attaches to a top surface of anvil  136  and has a contoured blade adjacent rotor  106  closely receiving cutters attached to tool holders  143  as rotor  106  rotates. Upper rear wall  108  is joined between upper right wall  113  and upper left wall  111  forming a rear portion of a hopper. Upper rear wall  108  is shown in this embodiment as sloping, but may be vertical. Also shown here is optional guide block  163  extending from upper left power head wall  111  which engages an outer surface of upper side compartment wall  121  when front compartment assembly  102  engages rear power head assembly  103 . 
       FIG. 7  is a perspective view of a front compartment assembly  700  showing front mating edges  140  and front bumper plate  122 . Front compartment assembly  102  has front compartment  114  and a ram  119  supported by modular front compartment frame  101  having a plurality of compartment supporting legs  104  extending between two longitudinally extending supporting beams. Front compartment  114  is defined by lower compartment plate  112  and an upward extending lower sidewall  118  proximate each longitudinal edge of lower compartment plate  112 . Lower compartment plate  112  has compartment plate lip  134  extending beyond lower sidewalls  118 . Lower sidewalls  118  each have a front mating edge  140 . Atop a rear modular section of each lower sidewall  118  extends an upper side wall  121 , also having front mating edge  140 .  FIG. 7A  is a cut-away portion of the front compartment assembly  700  of  FIG. 7  showing ram slide rail  124  longitudinally extending between each lower side wall  118  and upper sidewall  121  wherein an outwardly depending portion of ram  119  slides when ram  119  is longitudinally pushed or pulled to or from a rear power head assembly with a ram hydraulic system. Hydraulic cylinder  139  is a part of an embodiment of a separate hydraulic system for sliding front compartment assembly  102  on front compartment frame  101 . Preferably ram slide rails  124  have a polymeric lining reducing friction within ram assembly  115 . Lower side walls  118  have an outwardly extending flange  126  slidingly engaging compartment slide rails  127 . Optionally, outwardly extending flange  126  is a removable component part of sidewall  118 . Outwardly extending flanges  126  and compartment slide rails  127  enable front compartment assembly  702  to be slidingly separated from a rear power head assembly  103 . 
       FIG. 8  is a cutaway perspective view of a rear power head assembly and a front compartment assembly showing internal components thereof. Modular single shaft rotary grinder  800  is shown having a rear power head assembly  803  and front compartment assembly  802  in a split apart configuration. Rear power head assembly  803  comprises power head frame  116  having gear box  146  attached thereto. Gear box  146  is in mechanical cooperation with rotor  106  and transfers to rotor  106 . Moveable anvil  136  movably extends between right and left lower power head walls proximate a front lower portion of rotor  106 . Counter knife  109  moveably attaches to a top surface of anvil  136  and has a contoured blade adjacent rotor  106  closely receiving cutters depending from an outer cylindrical surface of rotor  106  as rotor  106  rotates. Upper left wall  111  and upper rear wall  108  form a rear portion of a hopper. Power head bumper plate  120  is shown centrally oriented within power frame  116 . 
     Front compartment assembly  802  has front compartment  114  and ram assembly  115  supported by modular front compartment frame  101  having a plurality of compartment supporting legs  104  extending from longitudinally extending supporting beams  117 . Front compartment  114  is defined by lower compartment plate  112  and an upward extending lower sidewall  118  proximate each longitudinal edge of lower compartment plate  112 . Lower compartment plate  112  has compartment plate lip  134  which extends over movable anvil  136  when front compartment assembly  802  is mated with rear power assembly  803 . Lower sidewalls  118  and upper sidewalls  121  each have a front mating edge  140 . Ram assembly  115  is covered with compartment top cover  128  and ram  119  has compartment rear wall  123  extending upward therefrom when ram  119  is in a retracted position as shown. Ram slide rail  124  longitudinally extends between each lower side wall  118  and upper sidewall  121  wherein an outwardly depending portion of ram  119  slides when ram  119  is longitudinally pushed or pulled to or from rear power head assembly  803  with a separate hydraulic ram system. Hydraulic cylinder  139  is a component part of a hydraulic system for sliding compartment assembly  102  for and aft front compartment frame  101 . Front compartment bumper plate  122  is shown centrally depending downward from a rear portion of compartment plate  112  for engagement with rear power head bumper plate  120 . 
     Also shown here are optional ram and compartment wiper assemblies. Rear wiper plate  149  is hingedly attached to compartment rear wall  123  with hinge  189 . Wiper  151  wipes an upper surface of ram assembly  115  when ram  119  is moved for and aft compartment plate  112 . Compartment cover  128  is modular in sections wherein a rear section can be removed allowing access to wipers  149 . Wipers  147  are adjacent an upper rear surface of ram  119  and have an outward force applied thereto wiping an inner surface of lower compartment side wall  118 . Wiper  145  extends a lower inner edge of ram  119  and wipes the upper surface of compartment plate  112 . Ram  119  can be extended beyond compartment  112  allowing access to pipers  147  and  145 . 
       FIG. 9  shows an alternative embodiment of the modular grinder of the present invention. Modular grinder  900  has front compartment assembly  902  and rear power assembly  903 . In this embodiment, front compartment assembly  114  rotates upward wherein front compartment plate lip  134  is raised from anvil  136  and the front lower corners of modular lower compartment sidewalls  118  are hingedly attached with hinges  926  to upper longitudinal supporting beams  117 . Upper supporting beams  117  horizontally extend atop compartment supporting legs  104  from front hinge attachments  926  and have front compartment assembly supports  927  thereon to engage outwardly extending flanges  126 . The upward rotation of front compartment assembly  902  provides working space between front compartment assembly  902  and power assembly  903  wherein rotor  106 , counter knife  109 , and other components of rotary grinder  900  can be serviced or replaced without the need to remove materials in front compartment  114  or the need to disassemble rotary grinder  900 .