Patent Publication Number: US-2021185923-A1

Title: Plant Trimming Assembly

Description:
FIELD OF THE INVENTION 
     This concept pertains to the trimming of plants and more particularly pertains to the trimming of plant buds and flowers and various other plant components. 
     BACKGROUND OF THE INVENTION 
     Plant trimming devices are used to trim and separate portions of a plant and/or a bud from other portions of the plant or bud. Traditional plant trimmers normally use a stationary blade to separate plant material. More recently there have been a number of machines and methods for cutting, trimming, and grinding plant materials for a variety of purposes such as for gardening, food processing, agriculture, and composting. 
     One such prior art device is described in US publication #2012/0279193 which is titled ‘Method and Apparatus for Trimming Buds and Flowers’ which was published on Nov. 11, 2012 by the inventor Donald Mosman. This device discloses a method for trimming plants, in particular buds and flowers, to remove unwanted plant material. The apparatus employs a combination of a slotted metal drum and a lawn mower type cutting reel that are rotated in the same direction but at different speeds to create a cutting interface that sheers the unwanted plant material off and then collects the debris through a novel vacuum manifold into a waste collection device. The publication describes a simple mechanical arrangement which allows adjustment of the cutting blades in relationship to the rotating drum in order to adjust the interface between the cutting blades and the drum to a claimed tolerance of between 0.002 and 0.006 inches. The inventors of the present application have learned that such simple mechanical adjusting mechanisms require frequent correction which creates significant downtime of the machine and unfortunately assumes that the slotted drum is relatively concentric and also that the cutting reel is relatively concentric. In practice it is difficult to maintain an adjustment between 2 to 6 thousandths of an inch using a simple mechanical stationary adjustment, as described in the Mosman publication. 
     In practice the inventors have found that the drums that are used in this type of machinery are never concentric and often exhibit run outs greater than 6 thousandths of an inch. This is a major reason maintaining a gap of 2 to 6 thousandths of an inch using the simple mechanical adjustment technique and mechanical arrangement described in the Mosman patent is difficult unless very expensive and practically cost prohibitive methods and materials are used to manufacture drums with extremely high precision. 
     Another piece of prior art is described in US publication #2017/0164557 entitled ‘Plant Trimming Device’ by the inventors Jacob Hawk Harold Et. al. which was published Jun. 15, 2017 and describes a plant trimmer which separates leaves or other peripheral plant material from the body portion of a plant. This publication also describes a rotatable basket having a set of ribs separated by openings in a basket side wall and a cutting assembly having at least one blade. The rotatable basket is configured to spin in the first direction and the cutting assembly may be configured to spin parallel to the rotatable basket in a second direction opposite the rotation direction of the basket. This disclosure describes how plant matter extending through one of the openings of the side wall of the rotatable basket may be sheered by the cutting face of the blade of the rotatable basket. 
     Two embodiments described in the Harold patent are depicted in  FIGS. 11 through 12  which describe a rotatable basket which is positioned concentrically within a cutting assembly. The rotatable basket and the cutting assembly may be configured to counter rotate with respect to one another or they may be configured to rotate in the same direction but at different speeds. The rotation of the rotatable basket causes the plant material to extend through one or more of the openings in the basket and at that point engage the plant material that is extending from the opening with the rotating cutting assembly, thereby trimming off portions of the plant material. 
     Unfortunately, this disclosure does not go into any detail as to how the inventors intend on maintaining a certain separation or distance between the rotatable basket and the cutting assembly other than the use of some internal spacers which are depicted in  FIG. 11   b.    
     This disclosure suffers the same problems and issues that the disclosure in the Mosman patent described above have, namely that the rotatable basket is never perfectly concentric and round nor is it uniform along the longitudinal length of the basket and there&#39;s little within either of these disclosures that takes into account the dimensional variations around the outer circumference of the rotatable basket and along the length of the rotatable basket. In other words, there is no cost effective mechanism that can compensate for radial and longitudinal run outs between the blade and the rotatable basket in either of these two patent disclosures, other then producing an extremely precise basket or drum. 
     The inventors have found through extensive research and development with trials and testing that it is necessary to be able to hold very close tolerances between the cutting surface or the cutting blade and the exterior surface of the “slotted drum” as it is denoted in this application, or the “rotatable basket” as it is described in the Harold patent, or the “slotted drum” as it is described in the Mosman patent. 
     In this application the inventors will describe a very accurate novel method and apparatus for maintaining very close tolerances between the cutting blade and the exterior surface of the slotted drum. 
     SUMMARY OF THE INVENTION 
     The present concept plant trimming assembly for trimming materials from plants includes;
         a frame;   a cylindrical slotted drum rotationally mounted to the frame along a longitudinal axis, the slotted drum includes an exterior surface and a longitudinally oriented internal passageway for receiving plant material there through;   a longitudinally oriented cutting assembly retainer is also rotationally mounted to the frame about the longitudinal axis such that it rotates concentrically around the outside of the exterior surface and along the length of the slotted drum;   a longitudinally oriented blade mounted to a cutting assembly which in turn is mounted to the cutting assembly retainer, the cutting assembly rotates in unison with the retainer around the outside of the exterior surface of the slotted drum; such that the cutting assembly is configured to maintain a pre-selected stand-off gap between a cutting edge of the blade and a circumferential contour of the exterior surface of the drum such that plant material projecting through a slot and beyond the stand-off gap will be trimmed off by the rotating blade cutting edge.       

     Preferably the concept further includes; at least two spaced apart guide cams mounted around the circumferential contour of the exterior surface of the drum; and at least two spaced apart cam followers each mounted to a distal end of the cutting assembly; wherein upon rotation of the cutting assembly retainer, the cam followers maintain contact with their respective guide cam in order to continuously maintain the pre-selected stand-off gap between the cutting edge of the blade and the circumferential contour of the exterior surface of the drum. 
     Preferably the guide cams are a flat band ring shaped strip guide cam with a flat inner side mounted to the circumferential contour of the exterior surface of the drum and a flat follower side for receiving the cam follower thereon. 
     Preferably the cam followers are rollers one operably connected to a left cam adjusting mechanism and the other to a right cam adjusting mechanism, the cam adjusting mechanisms attached to the distal ends of the blade. 
     Preferably wherein the cutting assembly further includes a floating blade assembly which rigidly holds the blade, wherein floating blade assembly is connected to the right and left cam adjusting mechanisms. 
     Preferably wherein the floating blade assembly includes a slotted blade support adjustably attached to a support holder with adjustment bolts for radially indexing the blade support relative to the support holder by turning the adjustment bolts, thereby selectively adjusting the blade longitudinal alignment to ensure blade alignment with the longitudinal contour of the exterior surface of the drum. 
     Preferably wherein the cutting assembly retainer includes longitudinally spaced apart disk shaped cutting assembly holders, the distance between two holders defines a segment which retains cutting assemblies there between, wherein the cutting assembly holders are held apart with longitudinally extending spacers. 
     Preferably the cutting assembly retainer is divided into at least two segments along the length of the drum thereby decreasing the length of each blade to substantially one half of the length of the longitudinal contour of the drum, thereby increasing the number of adjustable blades along the length of the drum which improves the accuracy to align the blades with the longitudinal contour of the drum. 
     Preferably wherein each segment includes at least two cutting assemblies evenly spaced around the circumference of the drum. 
     Preferably wherein the right cam adjusting mechanism is attached to a right cutting assembly bracket to which a first quick release mechanism is attached, and the left cam adjusting mechanism is attached to a left cutting assembly bracket to which a second quick release mechanism is attached, the quick release mechanisms for quick releasable attachment of the cutting assembly to the cutting assembly holders which provides for quick replacement of the cutting assembly and therefore the blade. 
     Preferably wherein the cam adjusting mechanisms include a compression spring  168  with one end of the spring operably attached to the support holder  146 , a threaded spring guide  173  and a roller bracket  182  supporting the roller  172 , and the other end of the spring is operably attached to the cutting assembly brackets  140 ,  142 , wherein turning a spring guide nut  174  about the threaded spring guide  173  adjusts the stand-off  208  distance between the blade cutting edge and the drum exterior surface such that undulations in the drum circumferential surface are followed by the roller cam thereby maintaining the preselected stand-off gap. 
     Preferably wherein the quick release mechanism includes a spring biased pin slid-ably attached to the cutting assembly bracket, the pin engages with a pin aperture in the cutting assembly holder and thereby release ably attaches the distal end of the cutting assembly to its respective cutting assembly holder. 
     Preferably wherein the drum is attached to the frame with drum bearings and the retainer is attached to the frame with retainer bearings. 
     Preferably wherein the blade is rigidly attached to and sandwiched between a blade backer and the adjustable blade support. 
     Preferably wherein the blade is angled at an angle theta relative to a tangent of the circumference of the exterior surface of the drum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With the intention of providing demonstration of characteristics of the device or method, an example or examples are given below without restrictive character whatsoever with reference to the corresponding figures of preferred embodiments of the device and method as follows: 
         FIG. 1  is a schematic top isometric view of a plant trimming assembly. 
         FIG. 2  is a side elevational view of the plant trimming assembly shown in  FIG. 1 . 
         FIG. 3  is a schematic side elevational view of the slotted drum together with the retainer and cutting assemblies. 
         FIG. 4  is a cross sectional view taken along the dashed lines shown in  FIG. 3  showing the slotted drum together with the cutting assemblies and the retainer. 
         FIG. 5  is a magnified view showing the interface between the slotted drum and the blade and a portion of the cutting assembly. 
         FIG. 6  is a front plan view of the cutting assembly. 
         FIG. 7  is a schematic isometric front top view of the cutting assembly shown in  FIG. 6 . 
         FIG. 8  is a schematic back isometric view of the cutting assembly shown in  FIG. 6 . 
         FIG. 9  is a schematic end view of the cutting assembly shown in  FIG. 8 . 
         FIG. 10  is a schematic isometric view of the slotted drum. 
         FIG. 11  is a schematic plan end view of the slotted drum shown in  FIG. 12 . 
         FIG. 12  is a schematic side elevational view of the slotted drum shown in  FIG. 10 . 
         FIG. 13  is a schematic isometric view of the cutting assembly retainer shown in  FIG. 14 . 
         FIG. 14  is a side elevational schematic view of the cutting assembly retainer. 
         FIG. 15  is a schematic end view of the cutting assembly retainer shown in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the attached  FIGS. 1 through 15  which depict a plant trimming assembly  100  which is used for trimming materials from plants and includes the following major components namely a frame  102  which includes a front mounting frame bracket  104  and a rear mounting frame bracket  106 . 
     The plant trimming assembly further includes a rotatable slotted drum  108  with a cylindrical exterior surface  204  which is supported by the mounting brackets  104  and  106  where in the slotted drum  108  is open on both ends. 
     The slotted drum  108  is adapted to receive plant material, not shown in the diagrams, namely at input ramp  120  and deliver plant material from the other end, namely at output ramp  122 . 
     At least one cutting assembly  114  is attached to a rotatable cutting assembly retainer  110  which is rotatably supported by the mounting brackets  104  and  106 . 
     A blade  154  is attached to the cutting assembly  114  and is mounted longitudinally and parallel to the cylindrical exterior surface  204  of the drum  108  and rotates around the exterior surface of the drum  108  with the cutting assembly retainer  110  where in the blade  154  cuts plant parts projecting through the slots  206  in the slotted drum  108 . 
     The blade  154  is resiliently biased towards the exterior surface  204  of the slotted drum  108  with a compression spring  168 . Right and left cam adjusting mechanisms  282  and  284  include a compression spring  168  with one end of the spring operably attached to the support holder  146 , a threaded spring guide  173  and a roller bracket  182  supporting the roller  172 , and the other end of the spring is operably attached to the cutting assembly brackets  140 ,  142 , wherein turning a spring guide nut  174  about the threaded spring guide  173  adjusts the stand-off  208  distance between the blade cutting edge  156  and the drum or cylindrical exterior surface  204  such that undulations in the drum circumferential surface namely the circumferential contour is followed by the roller cam thereby maintaining the preselected stand-off  208  gap. 
     Cam followers  172  which are depicted as rollers are mounted to the cutting assembly  114  and follow band ring shaped strip guide cams  190  which are attached to the circumferential contour concentrically around the circumference of the exterior surface  204  of the drum  108 . The cam followers  172  are configured to maintain a preselected standoff gap  208  between the cutting edge  156  of the blade  154  and the circumferential contour of the exterior surface  204  as the blades  154  rotate circumferentially around the exterior surface  204  of the drum  108 . The “circumferential contour” is essentially the outer circumference of drum  108  however the circumference will always exhibit some degree of run out or out of roundness which is reflected in the use of the words circumferential contour 
     The guide cams  190  of the plant trimming assembly are a flat ring shaped strip guide cam with a flat inner side  194  which is mounted adjacent to the circumferential contour of the exterior surface  204  of the drum  108  and a follower side  192  for receiving the cam follower  172  which is a roller thereon. Therefore the guide cam takes in the small variation namely the out of roundness and runout of the circumference of the drum. 
     The cam follower  172  is a roller cam follower  172  for rolling along the flat follower side  192  of guide cam  190 . Therefore the cutting assembly  114  includes a floating blade assembly  160  which is resiliently mounted to right and left cutting assembly brackets  140  and  142  respectively such that the floating blade assembly  160  follows the contour of the flat follower side  192  of the guide cam  190 . The cutting assembly brackets  140  and  142  are mounted to the assembly retainer  110 . 
     The floating blade assembly  160  of plant trimming assembly  100  further includes a support holder  146  with a support surface  186  which is mounted to an adjustable blade support  148  and wherein the support holder  146  is resiliently connected to spring mounts  170  to the cutting assembly brackets namely right cutting assembly bracket  140  and left cutting assembly bracket  142 . 
     The blade  154  is rigidly attached to and sandwiched between a blade backer  184  and the adjustable blade support  148 . The blade support  148  is configured to adjustably align the blade  154  to the blade holder  146 , and ultimately to the cylindrical exterior surface  204  in a longitudinal alignment. Similarly to the circumferential contour there is also a “longitudinal contour” which essentially is a longitudinal line along the length of the exterior surface of the drum which reflects the small variations in the diameter of the drum at any given point along its length. Unfortunately the drum longitudinal alignment of its exterior surface is not exactly true and smooth and straight but rather imperfect, and these imperfections are reflected in the term longitudinal contour 
     The blade support  148  also includes alignment slots  150  and alignment bolts  152  for selectively aligning the blade  154  with the longitudinal contour of the exterior surface  204  and holding the blade  154  in the selected position by tightening the alignment bolts  152 . 
     The blade  154  can also be angled at an angle theta  210  relative to a tangent  157  of the exterior surface  204  of the drum  108 . 
     The cutting assembly retainer  110  includes spacers  13  to mount and space apart the ring-shaped cutting assembly holders  112  which retain cutting assemblies  114  there between. The cutting assembly holders  112  are held apart with spacers  132 . The figures depict three cutting assembly holders namely input holder  224 , center holder  226  and out put holder  228 . 
     The cutting assembly  110  further includes a quick release mechanism  144  which are attached to the cutting assembly right and left brackets  140  and  142  respectively for quick release attachment of the cutting assembly  114  from the cutting assembly holders  112 . This quick release mechanism  144  includes a pin  136  which engages resiliently with a pin aperture  134  in the cutting assembly holders  112 . 
     In Use 
     Plant trimming assembly  100  therefore includes the following major components namely a frame  102  which has mounted thereon a slotted drum  108  and also a cutting assembly retainer  110  which has mounted thereon cutting assemblies  114 . Slotted drum  108  is rotated via any suitable drive mechanism, in this case is depicted as drum drive pully  126  for use with a motor drive and a V-belt for rotating slotted drum  108  at a preselected speed. 
     Likewise cutting assembly retainer  110  includes a retainer pulley  124  for use with a motor and veebelt drive for rotating cutting assembly retainer  110  with its cutting assemblies  114  mounted thereon at a preselected speed. 
     The slotted drum  108  and the cutting assembly retainer  110  may be rotating in the same direction or may be counter rotating relative each other, however in both cases there will be a speed differential between the slotted drum  108  and the cutting assembly retainer  110  in order to ensure that the blades  154  are moving relative to cylindrical exterior surface  204 . 
     Plant material is input into the plant trimming assembly  100  via input ramp  120  and into the open end of slotted drum  108  and moves along an internal passageway  280  in the drum. A spiral auger  230  and paddles  231  which is found within the internal passageway  280  of slotted drum  108  urges material along the longitudinal direction  216  of slotted drum  108  towards the output end  130  wherein material that manages to make it from the input end  128  to the output end  130  is dropped onto output ramp  122  as depicted in  FIG. 2 . 
     Slotted drum  108  is supported at the input end  128  at the input mounting flange  212  with drum bearings  116  and at the output end  130  at the output mounting flange  214  also by drum bearings  116 . As depicted in  FIG. 1  there are a total of four bearings which ride on the input mounting flange  212  and four bearings which ride on the output mounting flange  214  for rotatably mounting and holding slotted drum  108  in position. 
     Similarly cutting assembly retainer  110  is held in position at holder input rim  220  with retainer bearings  118  and at holder output rim  222  also by retainer bearings  118 . Similar to slotted drum  108 , cutting assembly retainer  110  is also supported by four retainer bearings  118  at input rim  220  and by four retainer bearings  118  at output rim  222 . In this manner both the slotted drum  108  and the cutting assembly retainer  110  has the freedom to rotate about a central longitudinal axis which is common or concentric to both the slotted drum and the cutting assembly retainer. 
     Slotted drum  108  is cylindrical in shape and includes a cylindrical exterior surface  204  which has a variety of different sizes of slots  206  and a cylindrical exterior surface  204 . 
     The inventors have found in practice that it is very difficult to produce a slotted drum  108  which is true meaning exhibits little to no runout in the transverse direction  218  namely a circumferential contour, and is 1764 straight and true along the longitudinal direction  216  namely a longitudinal contour, at a reasonable cost. In other words, it may be possible to make an almost perfectly concentric and true slotted drum  108  however the cost in producing such a drum becomes impractically high. Therefore, the inventors in this disclosure accept that there is a significant amount of non-trueness such as runout in the transverse direction and variations along the longitudinal length of the slotted drum  108 . In other words there is a circumferential contour and a longitudinal contour. 
     The inventors have also found that it is very crucial that the distance between the cutting edge  156  of blade  154  and the cylindrical exterior surface  204  of slotted drum  108  must be maintained at an extremely tight tolerance of no more than 2 to 4 thousandths of an inch to maintain trouble free trimming of plant material which is projecting through the slots  206  of slotted drum  108 . The gap or distance between the cutting edge  156  of the blade and the cylindrical exterior surface  204  is denoted as standoff gap  208  in  FIG. 5  which is a magnified view depicting the almost imperceivably small gap between the cutting edge  156  and the cylindrical exterior surface  204 . 
     The inventors have also found that in addition to the runout exhibited by the cylindrical exterior surface  204 , the run out changes or varies as one moves from the input end  128  to the output end  130 . For example at the input end which is proximate the input holder  224 , the runout may be one value whereas the runout proximate the center holder  226  may be another value and the runout at the output holder  228  may be yet another value and therefore the runout conditions or amount of runout of the slotted drum  108  may vary as one moves from the input end  128  to the output end  130  along the longitudinal direction of slotted drum  108 . 
     In order to maintain as consistent a standoff  208  as possible between the cutting edge  156  of blade  154  and the cylindrical exterior surface  204 , a floating blade assembly  160  has been devised and created by the inventors which is depicted more particularly in  FIGS. 6 through 9 . 
     Cutting assemblies  114  which include the floating blade assembly  160  includes a blade  154  which is mounted longitudinally and parallel adjacent the cylindrical exterior surface  204  of slotted drum  108 . 
     In  FIGS. 3   13 , and  14  the reader will note that two segments of cutting assemblies  114  are mounted to cutting assembly retainer  110 . The first segment  273  of cutting assemblies  114  is mounted between the input holder  224  and the center holder  226  and the second segment  275  of cutting assemblies is mounted between the center holder  226  and the output holder  228 . All of these cutting assemblies rotate about the slotted drum  108  in unison since they are securely mounted to cutting assembly retainer  110  which itself is rotating around slotted drum  108 . 
     The trueness or the longitudinal contour of slotted drum  108  along the longitudinal direction  216  to some extent determines the number of sets of cutting assemblies  114  which are used along the longitudinal direction  216 . 
     The greater the longitudinal variation of slotted drum  108 , the more sets of cutting assemblies  114  will be needed since the greater number of sets for a given slotted drum  108  will reduce the length of blade  154  and therefore allow for more precise adjustment of the standoff gap  208  between the cutting edge  156  of blade  154  and the cylindrical exterior surface  204 . At the extreme an infinite number of blades will allow for infinite adjustment. 
     Therefore the number of sets of cutting assemblies  114  will be affected by the absolute length of slotted drum  108  along the longitudinal direction  216  as well as the accuracy or the consistency of the runout along the length of the slotted drum  108 . For example a very short slotted drum  108  or a highly consistent slotted drum  108  which has very uniform runout along the entire length of the longitudinal direction  216  may only require one set of cutting assemblies  114  rather than the two sets of cutting assemblies as depicted in the drawings. 
     The initial standoff gap  208  between the cutting edge  156  and the cylindrical exterior surface  204  along the longitudinal contour is adjusted using the alignment slots  150  in adjustable blade support  148  and is ultimately locked into position using the alignment bolts  152 . 
     To help the user obtain a precise alignment, adjustment bolts  164  and stop nuts  166  are adjusted such that the proper circumferential contour standoff gap  208  is obtained between the cutting edge  156  of the blade  154  and the cylindrical exterior surface  204 . The floating blade assembly  160  is connected to the right cutting assembly bracket  140  and left cutting assembly bracket  142  via a compression spring  168  which terminates one end at a cam follower namely depicted as a roller  172  on either end of the support holder  146 . In the rest or the adjusting position, the blade cutting edge  156  is adjusted such that there is approximately a two thousandths per inch standoff gap  208  between the cutting edge  156  of blade  154  and the cylindrical exterior surface  204 . As the cutting assembly retainer  110  rotates about a slotted drum  108  thereby rotating the cutting assemblies  114  about the slotted drum  108 , the cam followers namely rollers  172  of the floating blade assembly  160  ride along flat follower side  192  of strip guide cams  190  which are rigidly mounted around the outer circumference of cylindrical exterior surface  204  as depicted in  FIG. 11 . The strip guide cams  190  closely follow the circumferential contour of the cylindrical exterior surface  204  and therefore adjust for runout which may be present in slotted drum  108 . As the roller cam follower  172  rolls along flat follower side  192  of the strip (or radial) guide cam  190  causes the blade  154  (or radial) to move upwardly in the transverse direction or downwardly in the transverse direction in order to maintain a consistent standoff gap  208  between the cutting edge  156  of blade  154  and the cylindrical exterior surface  204 . 
     In other words, as compression spring  168  is compressed and relaxed, it will maintain a consistent gap and/or a standoff gap  208  between the blade  154  and the cylindrical exterior surface  204 . 
     Therefore, the reader will note that the floating blade assembly  160  essentially compensates for circumferential contour and longitudinal contour of the slotted drum  108  and maintains as consistent as possible standoff gap  208  between cutting edge  156  of blade  154  and the cylindrical exterior surface  204 . 
     Eventually blade cutting edge  156  will wear and again a manual readjustment will be required. The tolerance or the standoff gap  208  consistency one is able to achieve with the presently described device we believe is significantly better and in many cases an order of magnitude better than any of the prior art devices known and/or described in the prior art. Put another way, a much greater circumferential contour and longitudinal contour can be tolerated and yet maintain a consistent stand off gap  208  compared to prior art devices. 
     In practice the inventors have found that they are able to hold a very close tolerance with a minimal amount of manual adjusting. The close tolerance has reduced gumming up of the blades significantly and overall improvements in efficiency of operation. 
     Typically the length of slotted drum  108  is 18 to 48 inches and preferably around 30 inches. Typically the diameter of slotted drum  108  is 6 to 24 inches and preferably around 12 inches. The dimensions may vary considerably however the inventor has found that a slot length of 3 to 8 inches and preferably about 5 inches works best and a slot width of 1 to ⅛ inches and preferably about ½ to ⅜ inches works best. Preferably the slot width is reduced from input end  128  of about ½ inch to the output end  130  of about ⅜ inch. 
     The width of the cutting assemblies  114  may vary depending upon the dimensional uniformity of the slotted drum  108 . In practice the width of cutting assembly  114  may range from 6 to 24 inches and preferably from 8 to 15 inches. As depicted in  FIG. 6  the width of blade  154  is somewhat less than the width of the cutting assemblies  114  by about 2 to 5 inches. 
     The drum  108  and the cutting assemblies  114  which are mounted to the cutting assembly retainer  110  are driven by independent drives known in the art and not shown via drum drive pulley  126  and retainer drive pulley  124 . The cutting assemblies  114  rotate at about 100 to 500 RPM and preferably at about 250 RPM. The drum  108  rotates at about 20 to 100 RPM and preferably at about 40 RPM.