Abstract:
A method and apparatus for reducing the size of wood members, particularly pan-shaped wood members known in the industry as “lilypads”, such that the orientation of the fibers of the lilypads are encouraged to be substantially perpendicular to the longitudinal and rotation axis of a cutting drum having a plurality of cutting members extending from its circumferential surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of prior application Ser. No. 09/356,390, filed Jul. 16, 1999, now U.S. Pat. No. 6,125,897 which is a division of application Ser. No. 08/995,453, which issued on Sep. 28, 1999 as U.S. Pat. No. 5,957,178 on an application filed Dec. 22, 1997 and claimed priority to provisional application No. 60/066,215, filed Nov. 20, 1997. 
    
    
     TECHNICAL FIELD 
     This invention relates in general to materials processing, particularly relates to wood processing, and most particularly relates to the processing of relatively flat pan-shaped “cut-off” members sometimes known in the industry as “lilypads”, which are provided when the ends of logs are “squared off” prior to further log processing. 
     BACKGROUND OF THE INVENTION 
     Wood and other material processing apparatuses and methods have been used for many years. In the instance of wood processing, methods and apparatuses including my U.S. Pat. Nos. 4,444,234, 4,569,380, 4,697,626, 4,776,375, 4,785,860, 4,874,024, (incorporated herein by reference) have been used for great benefit in both debarking, cutting, and “hogging” various wood elements, ranging from rock-laden wood processing “hogs” to specialized “knives” used to provide particular wood shavings. 
     Although such methods and apparatuses have been generally suitable for the tasks with which they are assigned, a new need in the industry has arisen for a suitable means for handling wood “lilypads”, which in certain instances can be provided in large quantities, such as in the case of large wood processing facilities. 
     Due to the scarcity and cost of timber, wood processing facilities (“mills”) have reduced waste by cutting logs more accurately. This is reflected in the creation of much shorter “trim-ends” than were previously cut. These trim-ends are approximately 3 inches and shorter, and have been come to be known as “lilypads”. 
     These lilypads are created when the ends of logs are trimmed to provide an end cut which is substantially “square”. These “lilypads” get their names from their appearances, which are substantially flat and disclike, and include lengths being substantially shorter than their diameters. 
     Prior art apparatuses have not been able to suitably process such wood elements, and tend to “shatter” them due to misalignment of the wood grain relative to the cutting edge as discussed in further detail below. Therefore the mills have instead used the lilypads for fuel by burning. However, there is a surplus of such matter, and burning has been found to pollute the atmosphere. Many scientists claim such burning has reached a critical level and certain governments have correspondingly placed restrictions or controls on such burning. 
     Therefore there is a need in the art for a method and apparatus for handling bulk quantities of lilypads, which will process the lilypad members in an efficient yet effective manner, providing wood chips having desirable characteristics for pulp and paper chip use. Methods and apparatuses are always needed which produce a high quality wood chip, with lower power requirements, which convert waste product to a high dollar item which is recyclable and non-polluting. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes deficiencies in the prior art by providing a method and apparatus for processing lilypad wood members which can handle a large number of lilypad members either sequentially or in batches, with the lilypad members being processed by cutting members to provide wood chips having desired and consistent characteristics. 
     Generally described, the present invention provides an apparatus for reducing the size of wood members, the apparatus comprising a drum rotatable about a longitudinal axis, a cutting member attached to the drum, a hopper including a floor and at least one side wall, a lower reciprocating pusher member configured for reciprocating movement from a retracted position to an extended position, and an upper pusher member configured for movement relative to the lower member and the frame such that the upper member extends above and overhangs the lower member to define a moving cavity. 
     Therefore it is an object of the present invention to provide an improved material processing apparatus. 
     It is a further object of the present invention to provide an improved wood processing apparatus. 
     It is a further object of the present invention to provide an apparatus for processing disclike wood members, sometimes referred to as “lilypads”. 
     It is further object of the present invention to provide a chipping action on a disclike “lilypad” member which is similar to the desired chipping action as if a log was parallel to the longitudinal axis of the chipper drum. 
     It is a further object of the present invention to provide an apparatus for processing wood members which includes a “moving pocket”, which retains the wood members in a desired orientation as the wood members are consumed by a cutting drum. 
     It is a further object of the present invention to provide an apparatus for processing disclike wood members having a wood grain substantially shorter than the longest dimension of said wood members. 
     It is a further object of the present invention to provide an improved method for processing wood. 
     It is further object of the present invention to provide an improved method for processing disclike wood members. 
     Other objects, features, and advantages of the present invention will become apparent upon reading the following detailed description of the preferred embodiment of the invention when taken in conjunction with the drawing and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial illustrative view of an isolated cutting drum  11  having cutting knives  12  mounted thereon. The cutting drum  11  rotates about a substantially vertical axis of rotation “R”, such that a lilypad wood member  50  is consumed by the cutting knives. The lilypad wood member  50  is oriented during the during cutting process as if it was part of an elongate log  52  and the longitudinal axis of the log is parallel to the rotational axis of the cutting drum. 
     FIG. 2 is a pictorial view of an isolated cutting drum  11  (having a cutting drum axis of rotation “R”) shown relative to a lilypad wood member  50  as it is guided towards the circumferential surface of the cutting drum by an upper pusher plate  40  and a lower pusher plate  60 . The respective oscillation paths  42 ,  62 , of the upper and lower pusher plates  40 ,  60 , are also shown. 
     FIG. 3 is side, partial cross-section view of a portion of the apparatus according to the present invention, showing a lilypad wood member  50  (not in cross section) being captured within a pocket defined by the upper and lower pusher plates  40 ,  60  and the floor defining member  32  (all three shown in cross section ), as the lilypad member is urged leftwardly towards the cutting drum  11  (a portion of which is shown but not in cross section). The cutting edges  13  of the cutting knifes  12  are shown generally for illustrative purposes in FIG. 3; more details of the cutting edges are shown in, for example, FIGS. 12A-12C. 
     FIGS. 4A-4E are side views showing various stages of a complete operating cycle of a two-plate system, showing an upper pusher plate  40 , a lower pusher plate  60 , a lilypad  50  being consumed, and a chipping drum  11  doing the consuming. 
     FIGS. 5A-5B are side partial cross-section views of a portion of the apparatus according to the present invention, showing lilypad members  50 A,  50 B, sliding down an inclined hopper wall  34  of the apparatus  10 . Lilypad member  50 B is “tipped” over by the upper pusher plate  40 , and lilypad member  50 B slides off the inclined wall  34  and onto the top of the upper pusher plate  40 , although it will be knocked off later into the paths of the members  40 ,  60 , later upon full retraction of the upper pusher plate  40 . 
     FIGS. 6A and 6B are top illustrative views of an upper pusher plate  40  including retention spikes  70  on its leading edge with FIG. 6A showing the retention spikes  70  not engaging wood, and FIG. 6B showing wood being engaged by the retention spikes. 
     FIG. 7 is a pictorial partial view of the leading arcuate face (also which may be referred to as a leading “edge” or “mouth”) of either of the upper or lower pusher plates  40 ,  60 , showing retention spikes used for wood gripping purposes. The arcuate nature of the leading, “pushing”, face allows the plate to conform substantially to the circumferential surface of the drum as shown in the other drawings. 
     FIG. 8 is a top plan view of the apparatus  10  according to the present invention, showing multiple lilypads  50  within the hopper  30 . 
     FIGS. 9A-9B are side partial cross sectional views of a portion of a second embodiment of an apparatus according to the present invention, showing a tipper plate  90  used in conjunction with an upper and lower pusher plates  40 ,  60 . FIG. 9A shows the tipper plate  40  tipping a lilypad member  50 A over, and then retracting to the position shown in FIG.  9 B. In FIG. 9B a second lilypad member  50 B slides from atop the inclined wall  34  to atop the upper pusher plate  40 , until is it later pushed off by the tipper plate  90  or by the stationary inclined wall  32  upon full retraction of the upper pusher plate  40 . 
     FIGS. 10A-10D are sequential side partial cross-sectional views of a third embodiment of the present invention, showing a four-plate apparatus in operation. FIG. 10A shows a wood lilypad member  50 A in the hopper with all four plates  140 ,  160 ,  40 ′, and  60 ′ fully retracted. FIG. 10B shows the two lowermost “primary” pusher plates  40 ′,  60 ′, fully extended (thus causing the wood lilypad member  50 A to be consumed). At this point, a second lilypad member  50 B has been dropped into the hopper and atop the fully-extended upper pusher member  40 ′. FIG. 10C shows the upper and lower “secondary” pusher plates  140 ,  160 , as they are extended towards the cutting drum (by a single hydraulic cylinder), pushing and containing the wood lilypad member  50 B. FIG. 10D shows all four of the pusher plates  140 ,  160 ,  40 ′ and  60 ′ fully extended. It should be understood that all four plates could be simultaneously retracted. 
     FIG. 11 is a transverse cross section of the pusher plates with upper pusher plate  40  shown by way of example, although this cross sectional configuration is also provided in the lower pusher plate  60  (not shown in FIG.  11 ). This cross section is taken along a plane normal to the reciprocating travel axis of the upper pusher plate, and shows a platelike metal portion  44 , a platelike lower bearing portion  46 , and two striplike side bearing portions  48 . 
     FIGS. 12A-12C show side, leading end, and top views, respectively, of a cutting knife  12  according to the present invention. As may be seen, such a configuration includes a main cutting edge  13   m  (including three shown serrations), a pair of cutting wings  13   w  and three cutting faces  13   f.    
     FIG. 13 is an exploded view of a knife assembly including the knife  13  and upper and lower knife retaining elements  19 ,  18 . The lower retaining element  18  is mounted to the cutting drum and the upper element  19  captures the knife  13  and is retained by an unshown bolt having a longitudinal axis along line L. 
     FIG. 14 shows the knife  13  in its mounted position. As may be seen, the sharpness angle of the main cutting edge is approximately 38 degrees, the clearance angle is approximately 5 degrees (5.315 degrees in one particular instance), and the rake angle is approximately 46 degrees. These approximate angles should total to ninety degrees. 
     FIG. 15 is a hydraulic system illustrative drawing. 
     FIG. 16 is an electrical schematic drawing. 
     FIG. 17 is an illustration of a prior art chipper  120  showing how such chippers can jam through gravity feeding. Disc chippers (not shown) are also known. 
     FIG. 18 is a side plan illustrative view of an alternate embodiment of the present invention, including a chipper disc  180  with a horizontal drive shaft  181 , and upper and lower pusher plates  182 ,  183 , with “square” pushing faces. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference is now made to the drawings, in which like numerals designate like elements throughout the several views. 
     General Construction and Operation 
     Generally described, one embodiment of the present invention includes the use of at least two substantially horizontal “pusher plates”, which are each slidably movable relative to an apparatus including a stationary floor and a horizontal-axis cutting drum. Disclike wood “lilypads” are dropped via conveyor or other suitable means onto the floor, and the two pusher plates are urged towards the lilypads and eventually cause at least some of them to be urged into contact with the cutting drum and to be consumed thereby. The relative positioning of the two plates as they come into the vicinity of the lilypad is important; the upper pusher plate overhangs the other such that a “moving pocket” is defined which tends to capture the disclike members in a desired orientation as they contact the cutting drum. 
     The Desired Orientation 
     Reference is first made to FIG. 1, to illustrate the manner in which the lilypad wood members  50  are oriented relative to a rotating cutting drum  11 . FIG. 1 is a pictorial illustrative view of an isolated cutting drum  11  having cutting knives  12  mounted thereon. The cutting drum  11  rotates about a substantially vertical axis of rotation “R”, such that a lilypad wood member  50  is captured within a pocket is consumed by the cutting knives. The lilypad wood member  50  is oriented the during cutting process as if it was part of an elongate log  52  and the longitudinal axis of the log is parallel to the rotational axis of the cutting drum. 
     As may be seen, lilypad wood members such as  50  are typically cut from the ends of typical elongate wood members such as a source log  52 . As is well known, the wood grain of such source logs runs along the longitudinal axis of the log. In the wood processing art, it has become known to process such logs with prior art knives or other suitable cutting members when the longitudinal axis  53  of the source log  52  is substantially parallel to the longitudinal and rotational axis of the cutting drum  11 . One reason for such desired orientation is due to the fact that such elongate log members lend themselves well to a “cradling” effect in which the log is cradled between the cutting drum and a stationary wall or anvil such as shown in my U.S. Pat. No. 4,785,860, or similarly cradled between a cutting drum and a plurality of toothed wheels drum as shown in my U.S. Pat. No. 4,444,234. 
     However, as noted above, as more accurate wood processing techniques have been developed, less waste is involved (the low-end trim is much shorter) and therefore there is more of a tendency to create “lilypads” such as  50  in FIG. 1, with the average length of the lilypads (also known as cut-offs”) being approximately 3″ thick×6″-36″ in diameter, although other dimensions are contemplated. 
     Therefore, it may be understood that the desired chipping action is similar to the desired chipping action as if a log was parallel to the longitudinal axis of the chipper drum, in that cutting is preferably done by slicing “along the log”, which takes less horsepower than if cutting with the end grain facing the drum. 
     Two-Plate Design Construction 
     As noted above, the wood lilypads must be oriented correctly to make an acceptable chip. It has been determined that there is difficulty in orienting “lilypad” elements, due to their relatively short fiber length. 
     The apparatus according to the present invention achieves such an orientation. Reference is now made to FIG.  2 . 
     FIG. 2 is a pictorial view of an isolated cutting drum  11  (having a cutting drum axis of rotation “R”) shown relative to a lilypad wood member  50  as it is guided towards the circumferential surface of the cutting drum by an upper pusher plate  40  and a lower pusher plate  60 . The respective oscillation paths  42 ,  62 , of the upper and lower pusher plates  40 ,  60 , are also shown. 
     The lower pusher plate  60  is configured to slidably move in a reciprocating fashion relative to the frame of the apparatus  10 . The upper pusher plate  40 , in one preferred embodiment, rests atop the lower pusher plate  60 , although as discussed later in this application, the upper pusher plate  40  is configured to slide relative to the lower pusher plate  60 , as well as to slide relative to the frame of the apparatus  10 . A sliding connection may be made by conventional means known in the art. In the case of the present invention, the sliding connection may be provided by the use of elongate bearing strips made of moly filled nylon or other prior art materials. 
     As described later in further detail, the upper and lower pusher plates  40 ,  60 , each move in a reciprocating manner along substantially horizontal and parallel travel axes. The paths of each of these pusher members are essentially the same length, beginning from a “retracted” position, and ending at a “extended” position. 
     The lower pusher plate is powered by a hydraulic cylinder. However, the upper pusher plate  40  is not powered, but instead rests atop and slides along with the lower pusher plate unless an outside force or object is encountered to overcome friction between the two plates  40 ,  60 , as discussed elsewhere. 
     Two-Plate Design Operation 
     Operation of the apparatus is now discussed in reference to Figs. FIGS. 4A-4E, which are sequential side views showing various stages of a complete operating cycle of a two-plate system, showing an upper pusher plate  40 , a lower pusher plate  60 , a lilypad  50  member being consumed, and a chipping drum  11  consuming the lilypad member  50 . 
     Operation of the apparatus is as follows. Referencing first FIG. 4A, “lilypad” wood members such as  50  are dropped into the hopper onto the floor  32  from a conveyor or other suitable means. The wood members can be dropped in one by one, or in bulk as desired. 
     The upper and lower pusher plates  40 ,  60 , begin their cycle from their positions shown in FIG. 4A. A hydraulic cylinder (not shown in FIGS. 4A-4E) attached between the lower pusher plate and the frame of the overall apparatus is then energized, forcing the lower pusher plate  60  to be urged towards an extended position. The upper pusher plate  40 , which rests atop the lower pusher plate  60 , is pushed along with the lower pusher plate due to the influence of friction between the two plates  40 ,  60 . During this “infeed” stroke, the upper pusher plate  40  extends beyond the lower pusher plate, causing a cavity  51  (see FIG. 4E) to be provided underneath the overhanging upper pusher plate  40 . This cavity  51 , which is eventually closed of and eliminated, is an important feature of the present invention and will be discussed in later detail. 
     As the upper pusher plate  40  nears the end of its stroke, it approaches a stationary stop member (not shown). The upper pusher plate  40  contacts the stationary stop, and is itself stopped from further travel, to remain in the position shown in FIG.  4 B. This is the fully “extended” position of the upper pusher plate  40 . However, as shown in FIGS. 4A- c,  the lower pusher plate  60  continues its travel, closing the cavity  51  provided by the upper pusher member until the lower pusher plate  60  travels to a desired position until it reaches a microswitch (not shown), which causes its travel to be reversed. At the instant of such travel reversal, the lower pusher plate  60  is at its fully “extended” position, which is shown in FIG.  4 C. 
     At the point shown in FIG. 4C at which the lower pusher plate  60  reverses its position from its “extended” position, it may be understood that both of the upper and lower pusher plate  40 ,  60  are fully extended. At this time, their arcuate leading edges are in close proximity to the outer, circumferential, surface of a cutter drum, which in the preferred embodiment includes a plurality of cutting knives such as known in the art. 
     After both have been completely extended, the upper and lower pusher plates  40 ,  60 , reverse their direction and more together to the positions shown in FIG. 4D under the influence of the double-acting hydraulic cylinder. As before, the upper pusher plate  40 , which rests atop the lower pusher plate  60 , is drawn backward along with the lower pusher plate due to the influence of friction between the two plates  40 ,  60 . 
     As the two plates  40 ,  60 , continue to be drawn backward, the upper plate  40  contacts a stationary stop  98 , which causes the upper pusher plate to stop at its fully retracted position shown in FIG.  4 E. However, the bottom pusher member  60  is moved further rearwardly (against the frictional force between the members  40 ,  60 ) to its final position shown in FIG.  4 E. 
     Upon complete retraction of the upper and lower pusher plates  40 ,  60 , more wood members can fall upon the horizontal sliding floor surface of the hopper. The pusher plates  40 ,  60  then again move from their retracted to their extended positions. The wood members  50  are then consumed by the cutting drum  11 , with the chips falling within the drum and removed as known in the art. 
     Reference is now made to FIGS. 5A-5B, which are side partial cross-section views of a portion of the apparatus according to the present invention. These figures show lilypad members  50 A,  50 B, sliding down an inclined hopper wall  34  of the apparatus  10 , with one lilypad member  50 B being “tipped” over by the upper pusher plate  40 , and lilypad member  50 B sliding off the inclined wall  34  and onto the top of the upper pusher plate  40 , although it will be knocked off later into the paths of the members  40 ,  60 , later upon full retraction of the upper pusher plate  40 . 
     As noted above, the upper pusher plate  40  “leads” the lower pusher plate  60  during the “infeed” stroke. It may be understood that the location of the stop  98  compared to the location of when the lower pusher plate  60  begins its forward motion results in the amount of overhang provided by the upper pusher member  40 . It should also be understood that the stroke paths of the two pusher members  40 ,  60 , differ in the amount of the overhang. 
     FIG. 11 is a transverse cross section of the pusher plates with upper pusher plate  40  shown by way of example, although this cross sectional configuration is also provided in the lower pusher plate  60  (not shown in FIG.  11 ). This cross section is taken along a plane normal to the reciprocating travel axis of the upper pusher plate, and shows a platelike metal portion  44 , a platelike lower bearing portion  46 , and two striplike side bearing portions  48 . 
     The upper pusher plate shown in FIG. 11 fits as snugly as possible within available tolerates between the side walls of the hopper, such that the lower bearing plate portion  46  slides upon the upper surface of the lower pusher plate, and the outwardly-facing surfaces of the side bearing portions  48  slide against inwardly-facing surfaces of the hopper. The lower pusher plate  60  slides a similar matter between the walls of the hopper, but its lower surface slides against the floor of the hopper. 
     As noted elsewhere in this application, molybdenum-impregnated nylon is used as the bearing material for elements  46  and  48 . 
     In one particular embodiment, when the top pusher plate reaches ¾ inches of the drum it is stopped by stops welded or bolted to the sides of the hopper. At this time material less than 3 inches thick (the thickness of the top plate) is trapped below the top pusher; the bottom pusher continues moving toward the chipper drum closing the 9 inch gap until it reaches ¾ inches of the drum. This gives the thin material, (log ends, tie cut offs, etc.), the stability necessary to make a good chip. 
     In the method discussion above, the two pushers come forward accordingly one at a time until the spikes on both are ¾ inches from the drum, whereupon they all withdraw simultaneously. As discussed later, for higher production and utilizing more knives in the drum, a second set of pushers with a powered pusher could be mounted on top of the first set of pushers. 
     Two-Plate Design with Tipper 
     FIGS. 9A-9B are side partial cross sectional views of a portion of a second embodiment of an apparatus according to the present invention, showing a tipper plate  90  used in conjunction with an upper and lower pusher plates  40 ,  60 . FIG. 9A shows the tipper plate  40  tipping a lilypad member  50 A over, and then retracting to the position shown in FIG.  9 B. In FIG. 9B a second lilypad member  50 B slides from atop the inclined wall  34  to atop the upper pusher plate  40 , until is it later pushed off by the tipper plate  90  or by the stationary inclined wall  34  upon full retraction of the upper pusher plate  40 . 
     The configuration of FIGS. 9A-9B operates as follows: the tipper plate  90  goes out and back, preferably tipping over lilypads such as the one shown in FIG.  9 A. After the tipper plate&#39;s retraction, the lower two plates operate as discussed in the design not including the tipper plate described earlier, although some dampening or speed reduction may be provided as discussed later with respect to controls and hydraulics. 
     Three or More Plate Designs and Methods of Operation 
     Another alternative to the embodiment is the use of a 3-level configuration, in which an upper pusher element is moved all the way in, and then a middle pusher element is moved all the way in, and then a lower pusher element is moved all the way in. All three can then be retracted. 
     Another embodiment includes the use of a “pair” of elements which interact similar to the two elements shown in FIGS. 10A-D. In this case, the lower “pair” will conduct the action described above, and then, the upper pair will perform a similar action, with the upper surface of the upper pusher member of the lower pair performing the same service of the floor of the hopper. 
     If for instance longer blocks are introduced, for example a dia. of 18″×10′ long the top pusher will set higher on the block making it more stable. If there were resistance in the chipping process the bottom pusher would automatically be moving forward to assist in the feeding process. The pushers can be different thicknesses depending on average block size. 
     The top pusher I described is depending on the bottom pusher for movement or power. The bottom pusher is moved by a hydraulic cylinder. The top pusher I will call the non-powered pusher. The non-powered pushers can be stacked several high depending on material length (thickness). The pushers would resemble inverted stair steps to better trap various size material. 
     Engaging Teeth or “Spikes” 
     Reference is now made to FIG.  7 . which shows that the leading arcuate pushing edges of the upper and lower pusher members can include multiple gripping teeth or “spikes”  70 , which are attached to the metal portion of the pusher plates and tend to “grip” wood members as they are being engaged by the cutting knives of the drum. These teeth, if used, can be a variety of heights and at various spacing. However, they can be 3-4 inches apart, in two rows, and approximately ¼-½ inches high. FIGS. 6A-6B show the spikes as they are mounted and as they engage and retain the wood members. This retention feature, combined with the feed system used can have a significant impact on power consumption, as cradling and “jamming” of the wood material is discouraged. 
     For comparison purposes, a prior art system which includes “crading” is shown in FIG.  17 . This system, which includes a horizontal chipper and accepts to logs via gravity drop, encourages cradling, wedging, and, effectively, jamming. As may be understood, such systems do not include the capability of controlled feeding as provided by the present invention, in which feed can be stopped or slowed upon high loading of the chipper drum. 
     Hopper Configurations 
     The lilypad members  50  can be conveyed or dropped onto the sloping end of the hopper. This will assist the lilypads in falling flat on the floor of the hopper. The sloped end of the hopper could be made of stainless steel, fiberglass or plastic with a magnet attached to the back of the sloped end to capture tramp metal. Screening holes in the floor of the hopper can be provided for sawdust and other small materials. 
     If the pusher assembly is made of stainless steel, fiberglass, or plastic, an electro magnet could be installed under the top layer and capture tramp metal. When the pusher is fully retracted the electromagnet can be turned off and an overhead magnet would attract the metal. The pusher&#39;s magnet would be turned on when it again enters the working area. In lieu of an overhead magnet, a flap type scraper could also be employed when the magnet is shut off on the return stroke. 
     As may be seen in for example FIGS. 5A-B, the shape of the chute tends to prevent wood lilypad members from falling atop the upper pusher member, while still providing efficient use of space. 
     The Knives 
     Reference is now made to FIGS. 12A-12C,  13 , and  14 . 
     FIGS. 12A-12C show side, leading end, and top views, respectively, of a cutting knife  12  according to the present invention. As may be seen, such a configuration includes a main cutting edge  13   m  (including three shown serrations), a pair of cutting wings  13   w  and three cutting faces  13   f.  Three serrations are shown which are each 0.010 inches deep and ⅛ inches wide. These serrations provide fiber-slitting edges. 
     FIG. 13 is an exploded view of a knife assembly including the knife  13  and upper and lower knife retaining elements  19 ,  18 . The lower retaining element  18  is mounted to the cutting drum and the upper element  19  captures the knife  13  and is retained by an unshown bolt having a longitudinal axis along line L. 
     FIG. 14 shows the knife  13  in its mounted position. As may be seen, the sharpness angle of the main cutting edge is approximately 38 degrees, the clearance angle is approximately 5 degrees (5.315 degrees in one particular instance), and the rake angle is approximately 46 degrees. These approximate angles should total to ninety degrees. 
     The Hydraulic Setup 
     As noted within this description, reciprocating movement of various plates is provided by the use of various hydraulic components, although other drive configurations are contemplated without departing from the spirit and scope of the present invention. However, it has been found advantageous to provide a system which moves more rapidly during its “retraction” stroke(s), as this is essentially machine downtime. 
     Assuming the system of FIGS. 9A-9B, reference is now made to the elements of FIG.  15 . 
     Hydraulic cylinder  101  is connected to and is configured to move the lower pusher plate  60 . 
     Hydraulic cylinder  102  (with cushions at both ends) is connected to and is configured to move the tipper plate  90 . 
     Relief valve  103  is used to relieve excessive hydraulic oil pressure allowing the hydraulic cylinder  101  to retract if impact occurs to plate  60 . 
     Adjustable flow control  104  controls speed of the stroke of plate  60  when pushing “lilypads” or other material toward cutting drum  11  and will still give full flow of hydraulic oil to cylinder  102  allowing the tipper plate  90  to move forward at high speed. 
     Adjustable flow control  105  controls the retracting speed of plate  60  and tipper plate  90 . 
     Electric solenoid operated hydraulic valve  106  controls cylinders  101  and  102 . Solenoid operated hydraulic valve to detour hydraulic oil to flow control valve  108 . 
     An adjustable flow control valve  108  is provided. Valves  108  and  107 , when activated, will restrict flow from the hydraulic pump and act as a decelerating valve for hydraulic cylinder  101 . Valves  108  and  107  will be controlled by a limit switch mounted a distance from the end of the return stroke of pusher plate  60 . A variable displacement pressure compensated hydraulic pump  109  is provided the energize the overall system. 
     Controls 
     Reference is now made to FIG. 16, to describe controls used with the configuration of FIGS. 9A-9B. 
     For controls one can use PLC with limit switches, pressure switches and amperage sensors on the drive motors to control feed rates, all safety plugs and emergency stop buttons. 
     Reference is now made to FIG.  16 . As may be seen, this electrical Schematic allows switching between manual (to cycle feed plates with a manual switch) to automatic to energize an automatic feed system. 
     When in the position shown in FIG. 16, Line  1020  is hot. Momentary contact of start switch will energize  1060  which will energize solenoid coil CR 3  and close CR 3 - 1  and CR 3 - 2  energizing line  1090 . Power will then go through LS 1  and to the second level of the start switch. 
     The initial engagement of the start will energize  1070  and energize CR 1  and will close CR 1 - 1  and CR 1 - 2 , energizing  1040  and T 1 . This will energize the valve to move the feed plates forward. 
     When the feed plates are all the way forward, LS 1  will engage and energize line  1130  and CR 2  which will drop out CR 2 - 1  de-energizing CR 1  and will drop out CR 1 - 1  and CR 1 - 2  to  1040  and T 1 . CR 2 - 3  is now closed energizing  1050  and T 2  which will energize the 4 way valve to reverse the Feed Plates. LS 3  will energize the decelerating valve near the end of the reverse stroke. 
     When the Feed Plates reach the reverse end of the stroke LS- 2  will close, energizing CR- 1 , closing CR 1 - 1 , opening CR 1 - 3 , which will de-energize CR- 2 , closing CR 2 - 1  closing CR 1 - 2  to  1040  and T 1  causing the Feed Plates to move forward and continue to Cycle. 
     Therefore it may be seen that when the LS 1  switch is triggered, the pusher plates go into reverse. When hit LS 2  is triggered, they go forward. When they hit LS 3 , they slow down. 
     Dimensions and Specifications 
     As shown in FIG. 11, the pusher plates (the lower pusher plate  60  is shown) in one embodiment include a steel portion  44 , 2 inches thick, with a 1 inch solid “wear plate”  46  of nylon bearing material attached underneath, and two 1 inch by 2 inch side bearing strips  48  running the length of the lower pusher plate  60 . A ¾ inch steel floor is used. 
     The system is a “3000 lb” system capable of a 3000 lb pushing force and 52″ pushing stroke, used in conjunction with a cutting drum of 50″ diameter and driven at approximately 210 RPM by a 100 HP motor, although at the time of filing that was thought to be possibly too much HP. 
     It should be understood that other alternate configurations having different sizes, rates, and power capabilities could also be used without departing from the spirit scope of the present invention. 
     Alternate Configurations 
     In the present invention, it has been noted that the weight of the upper pushing plate  40  tends to cause it to be frictionally engaged atop the lower pusher plate  60  to cause such friction to pull the upper member back simultaneously with the lower pusher plate  60  as the lower pusher plate  60  is retracted relative to the frame. However, a stop attached to the lower member which engages the upper member may also be used in case the upper member tends to bind along its sliding path. 
     Alternately, a hog may be used. If a hog is used, anvil members may also be provided along the wall where wood may be drawn. 
     The 9 inch upper plate overhang of the embodiments show can be different depending on material diameters. The pushers can also be different thicknesses depending on the average material size. 
     Instead of a long tipper plate such as shown in FIG. 5A-B, a shorter tipper plate (not shown) could be used which would only extend out partly towards the cutting drum (for example 1-2 feet from the edge of the infeed sloping member), to “kick” over lilypads which may remain on edge. 
     The feed rate is controllable by the speed of the pusher plate, and can be varied as desired for different material thicknesses. However, one configuration it has been found that for ¼″ thickness chips, with a “dual-flight” cutter confirmation (two cuts per revolution), a feed speed of ½′ per revolution is appropriate. It should be understood that some field adjustments as known in the wood chipping art are always possible; if excessive power consumption or “smoking” is occurring, the feed rate or pressure may be reduced, or if the chips are too thin the feed rate or pressure may be increased. 
     An additional hydraulic cylinder could also be used intermediate the upper and lower pusher plates if relative movement or a “dampening” effect is desired which is not provided by the frictional contact shown. 
     Instead of plastic bearing plates, wheels rollers or rails could also be used. 
     Instead of using hydraulics to push or pull the plates, chains, cable, or lead screws could also be used. 
     The concept of a contained cavity noted above could also be used with a horizontal chipper. 
     As shown in FIG. 18, a chipper disc  180  (having a vertical face) mounted to a horizontal drive shaft  181  (rotating about a horizontal axis) can be fed along the top of a supporting member  187  by a pair of pusher plates  182 ,  183 , (similar to those previously discussed but having “square” pushing faces), such that a wood member  185  (shown captured in a substantially closed cavity) can be turned into wood chips  186 . The knifes on the disc  180  can be as known in the art or as shown previously, and oriented to provide an optimal chip. 
     Power Requirements 
     It has also been found that power requirements for cutting with present vertical axis chipper configuration is less than prior art configurations such as shown in FIG.  17 . As shown in FIG. 17, the prior art configurations include a horizontal chipper spout which includes a wedging action against the drum to keep the wood stable while being chipped. However, such as configuration causes friction, heat, and wear, and uses excessive power. 
     In contrast, the pusher plates on the chipper of the present invention do not depend on wedging, and thus provide a more consistent wood chip. In contrast, the blocks are held by toothlike points and the pusher plate(s) are moved toward the drum at a controlled speed and no wedging is required. A further power saving feature could be the use of an amperage sensor on the motor which would slow or stop the pusher plate until the amperage decreases, followed by more of the pushing action. This “stop and go” feed motion is further facilitated by the design of the one apparatus according to the present invention, which does not depend on gravity for feeding purposes. If feed needs to be stopped, the pusher(s) are simply stopped and there are no wood members which are in a gravity-fed hopper which must still be consumed. 
     Miscellaneous Comments 
     The apparatus  10  according to the present invention is believed to have good possibilities for the medium to large production mills. The lower knives will likely do most of the work. For the larger, higher production mills, the lower pushers may be stacked. The bottom one would forward first, then the one above it moves forward until all pushers are forward. Then all pushers retract at one time and start the cycle over again. This does two things, increases production and distributes wood over more of the working area of the drum, utilizing more knives. The basic idea is that the wood material can be dropped into the hopper from a conveyor and will tend to be oriented when hitting the top of the pusher or the bottom of the hopper. 
     Conclusion 
     Therefore it may be seen that the present invention overcomes deficiencies in the prior art by providing a method and apparatus for handling bulk quantities of lilypads, which will process the lilypad members in an efficient yet effective manner, providing wood chips having desirable characteristics. 
     While this invention has been described in specific detail with reference to the disclosed embodiments, it will be understood that many variations and modifications may be effected within the spirit and scope of the invention as described in the appended claims.