Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of prior filed copending U.S. Provisional Patent Application Serial No. 60/305,941, Filed Jul. 16, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to wood chippers such as log slabbers and canters, and more particularly, to single-edged wood chipper blades which can be repeatedly removed from a wood chipper and sharpened, as needed, to prevent the need for disposing of multiple conventional blades over a prolonged period of repeated use. Each of the replaceable blades typically includes a blade mount base for engaging a rotary chipping head of the chipper, a clamp plate for engaging the blade mount base, and a blade body interposed between the blade mount base and the clamp plate. A blade edge is shaped in the front end of the blade body, and extends from between the blade mount base and the clamp plate. A blade babbitt is provided in the rear end of the blade body. Accordingly, the blade body can easily and repeatedly be removed from between the blade mount base and the clamp plate and sharpened, and again secured in place between the blade mount base and the clamp plate, as needed for optimum and economical operation of the chipper over a prolonged period. 
     Wood chippers such as log slabbers or canters typically include a pair of spaced-apart, power-rotated chipping heads each having multiple, inwardly-facing, double-edged blades mounted on the respective chipping heads. In operation of the chipper, the cutting edges of the blades are rotated in a circular path against the respective sides of a log as the log is longitudinally advanced between the rotating chipping heads. Accordingly, the blades of the chipping heads cut chips off the respective sides of the log to form planar longitudinal cuts in the log and generate wooden chips which can be used for various applications such as landscaping. Over a prolonged period of repeated uses, the dulled, conventional double-edged blades are typically removed from the chipping heads and, instead of being sharpened and replaced on the chipping heads, are discarded and replaced with fresh blades. Because each of the blades is expensive, discarding and replacement of the blades over time results in substantial costs to the chipper operator. 
     Various blades and blade-mounting techniques for wood chippers are known in the art. Typical of these are the blades detailed in the following patents: U.S. Pat. No. 5,511,597, dated Apr. 30, 1996, to Shantie, et al., describes a “Slabbing Chipper with Replaceable Knives and Wear Plate”; U.S. Pat. No. 5,819,826, dated Oct. 13, 1998, to Schmatjen, details a “Chip Cutting Knife with Spaced Deflector Ridges”; U.S. Pat. No. 5,820,042, dated Oct. 13, 1998, to Robison, discloses a “Wood Chipper Rotor Head Knife Holder and Knife Assembly”; and U.S. Pat. No. Re36,659, dated Apr. 18, 2000, to Toogood, describes a “Chipper with Detachable Facing Knives”. 
     An object of the present invention is to provide replaceable blades for wood chippers, which replaceable blades facilitate efficient and economical operation of wood chippers. 
     Another object of this invention is to provide replaceable blades for a variety of different types of wood chippers, including slabbers, canters and brush chippers. 
     Still another object of this invention is to provide replaceable blades for wood chippers, which replaceable blades can be removed from a wood chipper, sharpened and replaced on the chipper to avoid excessive disposal of chipper blades. 
     Yet another object of this invention is to provide replaceable blades for a variety of different types of wood chippers, which replaceable blades can be constructed in any desired size. 
     A still further object of this invention is to provide replaceable blades for wood chippers, typically including a blade mount base for engaging a rotary chipping head of the chipper; a clamp plate for engaging the blade mount base; a blade body interposed between the blade mount base and the clamp plate, which blade body includes a blade edge shaped in the front end of the blade body and extending from between the blade mount base and the clamp plate, and a blade babbitt provided in the rear end of the blade body. 
     SUMMARY OF THE INVENTION 
     These and other objects of the invention are provided in single-edged blades which can be removed, sharpened and replaced on wood chippers to prevent the need for disposing of multiple, conventional blades over a prolonged period of multiple uses. The replaceable blades of this invention typically include a blade mount base for engaging a rotary chipping head of the chipper, a clamp plate for engaging the blade mount base, and a blade body interposed between the blade mount base and the clamp plate. A blade edge is shaped in the front end of the blade body, and extends beyond the blade mount base and the clamp plate. A blade babbitt is provided in the rear end of the blade body. Accordingly, the blade body can easily and repeatedly be removed from between the blade mount base and the clamp plate and sharpened, and again secured in place between the blade mount base and the clamp plate, as needed for optimum and economical operation of the chipper over a prolonged period of multiple uses. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood by reference to the accompanying drawings, wherein: 
     FIG. 1 is a top perspective view of an illustrative embodiment of a replaceable blade for wood chippers of this invention, mounted on a wood chipper (in phantom); 
     FIG. 2 is a bottom perspective view of the replaceable blade illustrated in FIG. 1; 
     FIG. 3 is a top perspective view of an elongated embodiment of the replaceable blades for wood chippers; 
     FIG. 4 is a transverse sectional view, taken along section line  4 — 4  in FIG. 3, of a replaceable blade for wood chippers, illustrating a typical bolt technique for removably mounting the blade to a chipper; 
     FIG. 5 is an exploded, perspective view of the replaceable blade illustrated in FIG. 1; 
     FIG. 6 is an exploded, perspective view of the replaceable blade illustrated in FIG. 3; 
     FIG. 7 is a perspective view of a chipping head element of a log chipper, with multiple replaceable blades of this invention mounted on the chipping head; 
     FIG. 8 is a side view, partially in section, of the chipping head illustrated in FIG. 7; 
     FIG. 9 is a front view, partially in section, of the chipping head illustrated in FIG. 7; 
     FIG. 10 is an exploded, perspective view of the replaceable blades of this invention, more particularly illustrating a typical bolt technique for removably mounting the replaceable blades on the chipping head; 
     FIG. 11 is a perspective view of a chipping head for a brush chipper, with the replaceable blades of this invention mounted on the chipping head; 
     FIG. 12 is an end view of the brush chipper-type chipping head illustrated in FIG. 11; and 
     FIG. 13 is an exploded, perspective view of the brush chipper-type chipping head, illustrating a typical wedge technique for mounting the replaceable blades on the chipping head. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to FIGS. 7-10 of the drawings, in an illustrative embodiment the replaceable blades for wood chippers, hereinafter referred to as the replaceable blades, of this invention are each generally illustrated by reference numeral  1 . In typical application, multiple replaceable blades  1  are mounted on each of a pair of chipping heads  28  in a conventional log slabber or cantor (not illustrated), one of which chipping heads  28  is illustrated in FIGS. 7-10. The chipping heads  28  are disposed in spaced-apart relationship with respect to each other on respective rotor head drive shafts (not illustrated), and in operation of the log slabber or canter, a log carriage (not illustrated) advances a log (not illustrated) between the chipping heads  28  in a direction transverse to the rotational axis of the chipping heads  28 , which cut wood chips from the respective side margins of the log that overlap the cutting plane of the chipping heads  28 . Each chipping head  28  typically includes a rotor head  29 , fitted with a circular face plate  30  on the inside face thereof, which face plate  30  abuts against the corresponding side of the log as the log is cut by the rotating chipping head  28 . A shaft hub  31  is typically provided on the opposite, outside face of the rotor head  29 , and a key slot  32  located inside a shaft bore  31   a  which extends centrally through the shaft hub  31  and the rotor head  29  facilitates keyed attachment of the rotor head  29  to the rotor head drive shaft (not illustrated), extending through the shaft bore  31   a,  in conventional fashion. The rotor head  29  illustrated in FIGS. 7-9 is shaped in the configuration of a hexagon and includes six rotor faces  29   a  of substantially equal size, although the rotor head  29  may include three, four, or eight or more of the rotor faces  29   a,  depending upon the application of the log slabber or cantor. Elongated holders  33  extend outwardly from the respective rotor faces  29   a  of the rotor head  29 , and each includes a holder base  34  attached to the corresponding rotor face  29   a  typically by means of holder mount bolts  37 ; a blade mount portion  35  extending from the holder base  34 ; and an angled bracing portion  36  connecting the holder base  34  to the blade mount portion  35  of the holder  33 . As illustrated in FIG. 10, the blade mount portion  35  of each holder  33  is typically triangular in cross-section and is provided with a sloped blade mount surface  35   a,  through which extend multiple mount bolt openings  35   b  which receive respective blade mount bolts  25  that mount the replaceable blade  1  on the corresponding blade mount surface  35   a , as hereinafter described. (FIG. 10) 
     Referring next to FIGS. 1-6 of the drawings, the replaceable blades  1  of this invention can be any desired length depending on the application, wherein a short replaceable blade  1  is shown in FIGS. 1,  2  and  5  and a longer replaceable blade  1  is shown in FIGS. 3 and 6. Each replaceable blade  1  includes a blade mount base  2 , having a substantially rectangular base plate  2   a,  the bottom surface of which is typically provided with a base bevel  3  at the front end thereof. As particularly illustrated in FIGS. 5 and 6, a rectangular base block  5  is mounted on or formed integrally with the upper surface of the base plate  2   a , the rear end of which base block  5 , in combination with an elongated base flange  8  extending upwardly from the rear edge of the base plate  2   a , defines a base channel  4 , typically having a substantially rectangular cross-sectional configuration. The upper surface of the base plate  2   a  further defines a blade seat  7  between the front end of the base block  5  and the bevel  3  end of the base plate  2   a . An elongated base slot  6  extends through the base block  5  and the base plate  2   a  of the blade mount base  2 , for purposes hereinafter described. In the case of the longer replaceable blades  1 , multiple base slots  6  are typically provided in the blade mount base  2 , as illustrated in FIG. 6, the number of base slots  6  depending upon the length of the replaceable blade  1 . A blade body  18 , having a blade bevel  23  and a blade edge  19  shaped along the front end thereof, is provided with multiple spline notches  22  spaced along the rear end of the blade body  18  for receiving respective babbitt splines  21  of a blade babbitt  20 . A clamp plate  10  of the replaceable blade  1  is mounted on the blade mount base  2  to secure the blade body  18  on the blade mount base  2 , as hereinafter described. A plate bevel  10   a , having a bevel edge  10   b , is typically shaped in the top surface of the clamp plate  10 , at the front end thereof, and a clamp plate lip  12  is typically shaped in the bottom surface of the clamp plate  10 , adjacent to the bevel edge  10   b . The clamp plate  10  is typically further provided with a clamp plate flange  11  which extends downwardly from the bottom surface  13  of the clamp plate  10 , adjacent to the rear end thereof, which clamp plate flange  11  typically has a rectangular cross-section and fits in the companion base channel  4  of the blade mount base  2 , as hereinafter described. The upper portion of each of one or multiple bolt openings  15  extending through the clamp plate  10  is typically flared outwardly to form a bolt seat  14  defining a bolt shoulder  14   a . The bolt opening or openings  15  of the clamp plate  10  match in number the base slot or slots  6 , respectively, of the blade mount base  2 . 
     Referring again to FIGS. 1-8 and FIG. 10 of the drawings, in application the replaceable blades  1  are initially removably attached to the respective holders  33  (FIG. 10) of each chipping head  28  by means of one or multiple blade mount bolts  25 . Accordingly, as illustrated in FIG. 10, the blade mount base  2  is initially positioned on the sloped blade mount surface  35   a  of the holder  33 , with the base bevel  3  of the blade mount base  2  overhanging the upper edge of the blade mount surface  35   a , as illustrated in FIG. 4, and the base slot or slots  6  of the blade mount base  2  registering with the respective mount bolt opening or openings  35   b  of the holder  33 , as illustrated in FIGS. 5,  6  and  10 . The blade body  18  is then positioned on the blade seat  7  of the blade mount base  2 , with the blade babbitt  20  typically in contact with or adjacent to the front end of the base block  5  and the blade bevel  23  and blade edge  19  of the blade body  18  extending beyond the front end of the blade mount base  2 , as further illustrated in FIG.  4 . Finally, the clamp plate  10  is rested on the blade mount base  2 , with the bottom surface  13  of the clamp plate  10  disposed slightly above the base block  5  of the blade mount base  2 , the clamp plate lip  12  of the clamp plate  10  resting on the blade body  18  and the clamp plate flange  11  of the clamp plate  10  seated in the companion base channel  4  of the blade mount base  2 . Each of one or multiple blade mount bolts  25 , as required, are then extended downwardly through the respective bolt opening or openings  15  of the clamp plate  10  and the respective registering base slot or slots  6  of the blade mount base  2 , and threaded into the respective mount bolt opening or openings  35   b  in the blade mount portion  35  of the corresponding holder  33 , as illustrated in FIG.  4 . Accordingly, as illustrated in FIG. 8, the blade edge  19  of each blade body  18  protrudes beyond the face plate  30  on the rotor head  29 , to define a circular cutting plane of each chipping head  28  upon rotation of the chipping head  28 . As the chipping head  28  is rotated in the clockwise direction in FIG. 7, the blade edges  19  on the respective blade bodies  18  of the replaceable blades  1  on each chipping head  28  contact the side of a log (not illustrated) advanced between the adjacent chipping heads  28 , and cut wood chips from the corresponding side of the log as each chipping head  28  cuts a plane in the corresponding side of the log, in conventional fashion. After a prolonged period of operation of the log slabber or canter, the blade edge  19  on the blade body  18  of each replaceable blade  1  becomes dull and the cutting quality and efficiency of the chipping heads  28  decreases. Accordingly, the blade body  18  can be removed from the corresponding replaceable blade  1  and the blade edge  19  thereof sharpened using conventional methods in the art. Removal of the blade body  18  is accomplished by unthreading the blade mount bolt or bolts  25  from the respective mount bolt opening or openings  35   b  of the holder  33  and removing the blade mount bolt or bolts  25  from the base slot or slots  6  of the blade mount base  2  and the registering bolt opening or openings  15  of the clamp plate  10 ; lifting the clamp plate  10  from the blade mount base  2 ; removing the blade body  18  from the blade seat  7  of the blade mount base  2 ; sharpening the blade edge  19  of the blade body  18 ; and re-assembling the replaceable blade  1  by means of the blade mount bolt or bolts  25 , as heretofore described. It will be appreciated by those skilled in the art that the blade edge  19  of the blade body  18  can be sharpened multiple times until the blade bevel  23  and blade edge  19  encroach upon the area immediately adjacent to the spline notches  22  spaced along the rear edge of the blade body  18 , at which point the blade body  18  is discarded and another blade body  18  is replaced in the replaceable blade  1 . 
     Referring next to FIGS. 11-13 of the drawings, in another embodiment the replaceable blades, each generally illustrated by reference numeral  46 , are adapted for attachment to a conventional chipping head  40  for a brush chipper system (not illustrated). Such a chipping head  40  typically includes a generally cylindrical rotor head  41 , provided with multiple, longitudinal blade mount channels  42  which define a rotor head body  41   a  on one side of each blade mount channel  42  and a rotor head arm  41   b  on the opposite side of each blade mount channel  42 . The rotor head  41  is traversed by a central shaft bore  43  which includes a key slot  44  for attaching the rotor head  41  to a rotor head drive shaft (not illustrated). As illustrated in FIG. 13, each replaceable blade  46  typically includes a blade mount base  2 , similar in construction to the blade mount base  2  described above with respect to the replaceable blades  1  illustrated in FIGS. 1-10, but typically lacking the elliptical base slot or slots  6  (FIG.  6 ). The blade body  18  of the replaceable blade  46  is substantially the same in construction to the blade body  18  of the replaceable blades  1 , having the blade bevel  23 , blade edge  19  and blade babbitt  20 . The clamp plate  10  is similar in construction to the clamp plate  10  of the replaceable blades  1 , but typically lacks the bolt opening or openings  15  (FIG. 6) and corresponding bolt seat or seats  14 . As particularly illustrated in FIG. 12, each replaceable blade  46  is held in place in the corresponding blade mount channel  42  by means of an elongated wedge  47 , with the blade mount base  2 , blade body  18  and clamp plate  10  elements of the replaceable blade  46  interposed between the rotor head arm  41   b  and the wedge  47 , and the wedge  47  interposed between the clamp plate  10  and the rotor head body  41   a . Accordingly, as illustrated in FIG. 13, the bottom surface of the blade mount base  2  of the replaceable blade  46  engages the corresponding rotor head arm  41   b  of the rotor head  41 , while the upper surface of the clamp plate  10  engages one side of the wedge  47 , and the opposite surface of the wedge  47  engages the corresponding rotor head body  41   a . The blade body  18  is interposed between the clamp plate lip  12  of the clamp plate  10  and the blade seat  7  of the blade mount base  2 , as heretofore described with respect to the replaceable blades  1  of FIGS. 1-10, with the blade edge  19  and blade bevel  23  of each blade body  18  extending beyond the outer curvature of the rotor head  41 , as particularly illustrated in FIG.  12 . As further illustrated in FIG. 13, the wedge  47  is mounted in the corresponding blade mount channel  42  by means of multiple wedge mount bolts  48 , extended through respective bolt openings  47   a  provided in the wedge  47 , and threaded into respective threaded bolt openings  47   b , provided in the rotor head  41  at the bottom of each blade mount channel  42 . In use, as the chipping head  40  is rotated under power applied to the rotor head drive shaft (not illustrated) in the clockwise direction in FIG. 12, the blade edges  19  of the respective replaceable blades  46  alternately and repeatedly contact sticks, limbs or brush (not illustrated) fed into the brush chipper and cut wood chips from the sticks, limbs or brush, in conventional fashion. Removal of the blade body  18  from the replaceable blade  46  is facilitated as needed, for sharpening as heretofore described, by unthreading the wedge mount bolts  48  from the respective bolt openings  47   a  of the wedge  47 ; removing the wedge  47  from the blade mount channel  42 ; and removing the blade body  18  from between the blade mount base  2  and the clamp plate  10  for sharpening. The sharpened blade body  18  is replaced on the rotor head  41  by re-positioning the blade body  18  between the blade mount base  2  and the clamp plate  10  and again securing the wedge  47  in the blade mount channels  42  by means of the wedge mount bolts  48 . 
     It will be appreciated by those skilled in the art that the replaceable blades of this invention facilitate tremendous savings in costs associated with operating various types of wood chippers, by enabling each blade to be sharpened and re-used multiple times without the necessity of discarding of the blade after it becomes dull through multiple usages. It will be further appreciated by those skilled in the art that the replaceable blades are capable of use on a variety of wood chippers of various design, including but not limited to log slabbers, canters, brush chippers and chip-n-saws. 
     While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications can be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.

Technology Category: 7