Patent Publication Number: US-7219706-B2

Title: Apparatus having adjustable saws for wood cutting

Description:
FIELD OF THE INVENTION 
   The present invention relates to an apparatus having adjustable saws for wood cutting, particularly for use in log and lumber processing in a lumber mill. 
   BACKGROUND OF THE INVENTION 
   In order to produce squared lumber from a log, curved or wany edges of the log must be removed. To optimize the number of boards that can be obtained from the log, boards of optimum size are identified that will substantially fill the cross-sectional area of the log, leaving a number of such wany edges. In a process known as “profiling,” a cutting head (also known as a “profiling head”) is used to cut or chip away the wany edges, and this may be done before the boards are sawed from the log. Particularly, the cutting head cuts a corner that extends along the length of the log and that defines an outer side of one board and at least part of the upper or lower face of an adjacent board. To cut the corner, the cutting head rotates about an axis and has cutting surfaces oriented at right angles with respect to each other. 
   The cutting head has in the past typically included a knife for cutting the aforementioned upper or lower face in the example given above, the face defining a plane that is parallel to the axis of rotation of the cutting head (“facing cut”), and a saw for cutting the aforementioned outer side (“slicing cut”), which defines a plane that is perpendicular to the axis of rotation. More recently, cutting heads have been provided which employ knives for making both the slicing cut and the facing cut. 
   The speed of the profiling operation is increased if the wany edges for a number of boards can be removed by the same cutting head. A cutting head that can be used to cut away two wany edges at one time has at least one additional set of knives. The knives of the additional set are disposed a different radial distance from the axis of rotation than the first knives and are displaced axially therefrom as well. 
   For example, the first knives may be used to cut a first corner defined by an outer side of a first board and at least part of the upper face of a second board that lies beneath and extends laterally beyond the first board. The additional knives may simultaneously be used to cut an adjacent corner defined by an outer side of the second board and at least part of the upper face of a third board that lies beneath and extends laterally beyond the second board. The difference in radial positioning of the first knives relative to the additional knives, as well as the difference in axial positioning of the first knives relative to the additional knives, may define either the thickness of one of the boards or the difference in width between two adjacent boards. The absolute positioning of all of the knives of the cutting heads used to profile the log, in concert with the positioning of the cutting heads themselves, defines the dimensions of board lumber sawn from the log. 
   Examples of adjustable cutting heads are found in Dietz, Disclosure Document DE 44 19 324 (“Dietz”) and Linck, European Patent Application No. 96107714.6 (“Linck”). Dietz discloses an outer corner milling machine and an inner corner milling machine, each resembling a pot, one lying at least partially within the other. Each of the corner milling machines is adapted to cut a corner and is equipped for this purpose with a cleaver on the circumference surface and a plane blade oriented at right angles to the cleaver. “Adjustment units” are used to adjust the axial spacing between the two corner milling machines. The “adjustment units” are not described, but appear to be electric motors. Radial adjustment is not provided, and axial adjustment appears to require feed-back control of the motors to find and maintain a command spacing. This spacing can change as a result of the forces encountered by the milling machines and at least some time will be required for the controller and feedback mechanism to restore proper spacing, resulting in imprecise cutting. 
   Linck discloses a milling head having a large diameter ring of cleavers and a smaller diameter ring of cleavers. The cleavers have their cutting edges aligned with the axis of revolution of the milling head. The cleavers are attached to cleaver carriers which are fastened with screws to respective cleaver supports. The radial disposition of the cleaver supports can be adjusted by loosening the screws. The cleaver supports can also be moved in axial rails within the carriers and can be locked in at different axial positions with terminal blocks and screws. Disksaw segments are installed between the cleavers in the smaller ring. These are stated as being adjustable but no means for adjusting the disksaw segments is disclosed. Moreover, while the position of the cleavers can be adjusted both axially and radially, holding the cleavers in position depends on frictional forces exerted by tightening screws, so that there is no provision for positively locking the position of the cleavers. 
   Another problem with such cutting heads generally is that they are prone to load up with sawdust. 
   Accordingly, there is a need for an apparatus with adjustable saws for wood cutting that provides for the advantages inherent in the use of saw blades for cutting multiple corners in the wood, outstanding ease of adjustment and positive locking of the saws in their cutting positions, and resistance to the accumulation of sawdust, to minimize required maintenance and maximize the effectiveness of the wood cutting process. 
   SUMMARY OF THE INVENTION 
   The invention disclosed herein is an apparatus having adjustable saws for wood cutting. Within the scope of the invention, there is a cutting head adapted for rotation about an axis, the cutting head having at least two spaced apart disk-saws for producing respective slicing cuts in an article of wood, the saws defining respective distinct outer cutting diameters. The disk-saws may comprise separate disk-saw segments. 
   In a preferred embodiment of the invention, the cutting head includes in addition at least one set of knives for producing respective facing cuts in the article of wood, the sets of knives defining distinct outer cutting diameters. 
   Preferably, the disk-saws are bolted to the cutting head and spaced apart therefrom adjustable amounts by interdisposed control plates of predetermined thicknesses. 
   Preferably, a first one of the disk-saws defines an annular ring having an inner diameter, and the outer cutting diameter for the first disk-saw is greater than the outer cutting diameter of a second one of the disk-saws. The outer cutting diameter of the second disk-saw is then less than the inner diameter of the first disk-saw, so that the second disk-saw is nested inside the first disk-saw while remaining axially displaceable therefrom. 
   Preferably, the cutting head is relieved behind at least the first disk-saw to permit sawdust that migrates past the cutting teeth of the second disk-saw, into the space defined by the inner diameter of the first disk-saw, the second disk-saw and the cutting head, to exit through the cutting head. 
   Therefore, it is a principal object of the present invention to provide a novel and improved apparatus having adjustable saws for wood cutting. 
   It is another object of the present invention to provide such an apparatus that provides for the advantages inherent in the use of saw blades for cutting multiple corners in the wood. 
   It is a still another object of the present invention to provide such an apparatus providing for ease of adjustment of the cutting position of the saws. 
   It is yet another object of the present invention to provide such an apparatus providing for positive locking of the saws in respective cutting positions. 
   It is a further object of the present invention to provide such an apparatus that minimizes required maintenance and maximizes the effectiveness of the wood cutting process. 
   It is yet a further object of the present invention to provide such an apparatus that minimizes the accumulation of sawdust on the saws. 
   The foregoing and other objects, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the following drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of an apparatus for cutting an article of wood according to the present invention. 
       FIG. 2  is side elevation of the apparatus of  FIG. 1 . 
       FIG. 3A  is a cross-section of a log. 
       FIG. 3B  is a cross-section of the log of  FIG. 3A  as operated on by the apparatus of  FIG. 1 . 
       FIG. 3C  is the cross-section of  FIG. 3B  shown with boards of lumber identified. 
       FIG. 4  is a pictorial view of a cutting head according to the present invention, showing a front side of the cutting head. 
       FIG. 5  is an exploded view of the cutting head of  FIG. 4 . 
       FIG. 6  is a side view of the cutting head of  FIG. 4 , showing a rear side of the cutting head. 
       FIG. 7A  is a pictorial view of a representative knife for use with the present invention, showing a top side of the knife. 
       FIG. 7B  is a pictorial view of the knife of  FIG. 7A , showing a bottom side of the knife. 
       FIG. 8  is an exploded view of a portion of a cutting head having two sets of knives according to the present invention. 
       FIG. 9  is a plan view of a second embodiment of an apparatus for cutting an article of wood according to the present invention. 
       FIG. 10A  is a plan view of the cutting head of  FIG. 4 , showing nested disk-saws in a first relative axial position. 
       FIG. 10B  is a plan view of the cutting head of  FIG. 8A , showing the nested disk-saws in a second axial position. 
       FIG. 11  is an exploded view of the cutting head of  FIG. 4 , showing a rear side of the cutting head. 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , an apparatus  8  for cutting an article of wood  14  is shown with four cutting heads  10 . The article of wood  14  is, in this example, a log shown in cross-section. Corners are being cut from the log by the cutting heads  10  as the log passes the cutting heads in the direction indicated as “flow” in  FIG. 2  in a milling process known as “profiling.” This process configures the log from the roughly circular cross-section shown in  FIG. 3A  to that shown in  FIG. 3B . While such profiling of logs is an exemplary use of the present invention, the apparatus  8  may be used for cutting any article. 
   By cutting wany edges from the log with the cutting heads, the cross-section of the log as shown in  FIG. 3B  has been optimized for cutting pieces  18  of board lumber, as depicted in  FIG. 3C . The cutting heads  10  rotate about respective axes of rotation “L” as shown in  FIG. 1 . The cutting heads may be moved in the direction of the arrows shown in  FIGS. 1 and 2  to accommodate logs of different diameters. 
   Turning to  FIG. 4 , a preferred cutting head  10  having adjustable saws according to the present invention has two disk-saws  11 ,  13  with associated cutting teeth  11   a ,  13   a . Each cutting tooth  11   a ,  13   a  has two perpendicular cutting edges  11   a   1  and  11   a   2 , and  13   a   1  and  13   a   2 , respectively. The cutting edges  11   a   1  and  13   a   1  are parallel to the axis or rotation “L,” and the cutting edges  11   a   2  and  13   a   2  are perpendicular to the axis. 
   The disk-saws are spaced apart along the axis “L.” The cutting teeth  11   a ,  13   a  define distinct outer cutting diameters D 11  and D 13  of the disk-saws. The outer cutting diameter of the disk-saw  13  is chosen as being the greater outer cutting diameter for purposes of the discussion herein. While shown as integral parts for simplicity, the flat, circular disk-saws  11  and  13  may comprise any number of separate disk-saw segments, which may facilitate repair and replacement of the disk-saws, as well as maintenance of the apparatus generally. Also, while two disk-saws are shown and described as preferred, any number of disk-saws may be provided. Referring back to  FIG. 1 , the disk-saws  11  and  13  of a particular cutting head  10 , as they are rotated about the axis “L,” produce respective slicing cuts C s11 , C s13 , and facing cuts C f11 , C f13 , on the log  14 . 
   An outstanding feature of the cutting head  10  according to one aspect of the invention is that it provides for adjusting the relative axial positioning of the disk-saws  11 ,  13 , by the inclusion or deletion of one or more control plates  20 , such as shown in  FIG. 5 . Both the absolute and relative axial positions of the disk-saws may be adjusted by appropriate selection and placement of the control plates  20 . In the example shown, a single control plate  20  is interdisposed between the disk-saw  11  and a body portion  10   a  of the cutting head  10 . Additional control plates  20  may be stacked together with the control plate  20 , and any number of similar control plates may be interdisposed between the disk-saw  13  and the body portion  10   a.    
   In a preferred embodiment of the invention, the control plates include apertures  15   c  matching corresponding apertures  15   a  and  15   b , through the disk-saw and the body portion respectively, permitting bolts  15  used to mount the disk-saws to the cutting head  10  to pass therethrough. Other adaptations of the control plates  20  and the cutting head  10  may be employed to achieve the same function without departing from the principles of the invention. 
   As shown in  FIG. 5 , the control plates are flat pieces of metal of predetermined thickness, preferably, though not necessarily formed in an annular configuration. While a single annular control plate is shown for axially positioning the disk-saw, smaller, individual control plates may be employed at selected bolt locations to produce the same result. 
   The difference in the relative axial positioning between the disk-saws  11  and  13  is shown in  FIG. 1  as the distance “a.” Referring to  FIG. 3C , this distance “a” may be used to define either the difference in width between two adjacent boards  18   a  and  18   b , or the thickness of a single board  18   c . The absolute positioning of the disk-saws  11  and  13  of opposed pairs of cutting heads  10  provides the absolute dimensions of the boards  18 . The control plates provide for such positioning in discrete, precisely defined steps, and positioning is positively and accurately maintained without readjustment regardless of the amount of use and wear of the cutting head. 
   The control plates are highly economical to produce, and provide for substantially reducing the mechanical complexity of the cutting head, resulting in further savings in initial cost, maintenance and repair. By use of the control plates  20 , the dimensions of different boards  18  may be optimized to minimize the amount of the wany material that must be removed from the log and thereby to maximize the size of the boards. 
   Turning to  FIG. 6 , according to another aspect of the invention, the cutting head  10  preferably includes in addition to the disk-saws at least one set of knives K. A representative knife K having dual cutting edges  23   a ,  23   b  is shown in  FIGS. 7A and 7B . The knives K as they rotate about the axis “L” produce respective semi-cylindrical facing cuts C K  ( FIG. 1 ) on the log  14 . The outer cutting edges ( 23   a  as shown in  FIG. 6 ) of the knives K define an outer cutting diameter for the knives with respect to the axis of rotation “L.” Additional sets of knives may be employed, and the axial and radial positioning of the knives may be adjustably controlled with control plates similar to the control plates  20 , such as described in the assignee&#39;s patent application Ser. No. 10/081,444. 
   For example, turning to  FIGS. 8 and 9 , a first set of four knives K a  may be provided on a body portion  12   a  that is bolted to the cutting head  10  for producing a facing cut C ka  on the log at a first outer cutting diameter. A second set of knives K b  may also be provided on a body portion  12   b  that is bolted either to the cutting head  10  (not shown in  FIG. 8 ) or the body portion  12   a  for producing a facing cut C kb  on the log at a second outer cutting diameter that is distinct from the outer cutting diameter of the first set of knives K a . Base outer cutting diameters are defined by the radial size of the respective body portions  12 . 
   In addition, the radial positioning of the knives may be further adjusted from their base radial positioning as defined by the body portions  12  themselves, by the use of one or more control plates  21  ( FIG. 9 ) interdisposed between clamping mechanisms  30  for the knives and the body portions  12  and held in place such as by the use of bolts  15 . Like the control plates  20 , the control plates  21  are flat pieces of metal of predetermined thickness that provide for such positioning in discrete, precisely defined steps, and positioning is positively and accurately maintained without readjustment regardless of the amount of use and wear of the cutting head. 
     FIG. 8  also illustrates the use of a control plate  22  providing for relative axial positioning of the two sets of knives K a  and K b . One or more of the control plates  22  may be interdisposed between the body portions  12   a  and  12   b  and held in place such as by the use of bolts  15 . As will be readily appreciated, suitably disposed control plates  22  may also be used to adjust the absolute axial positions of the two sets of knives. Like the control plates  20 , the control plates  22  are flat pieces of metal of predetermined thickness that provide for such positioning in discrete, precisely defined steps, and positioning is positively and accurately maintained without readjustment regardless of the amount of use and wear of the cutting head. 
     FIG. 9  also illustrates the use of three disk-saws,  11 ,  13  and  9 , to show how the concept may be generalized. The disk-saws produce respective slicing cuts C s11 , C s13 , and C s9 , and respective facing cuts C f11 , C f13 , and C f9 , on the log  14 . The facing cut C f9 , in particular, is aligned with the facing cut C ka  of the adjacent set of knives K a , i.e., the outer cutting diameter of the disk-saw  9  is the same as the outer cutting diameter of the set of knives K a . Additional disk-saws may also be employed as desired, along with any number of sets of knives or any other desired elements. 
   Turning to yet another aspect of the invention, as mentioned, the disk-saws define respective outer cutting diameters D. In  FIGS. 4-6 , the disk-saw referred to as  13  is shown as having a greater outer cutting diameter D 13  than the outer cutting diameter D 11  of the disk-saw  11 . In that case, the disk-saw  13  is preferably provided as an annular ring having a corresponding inner diameter d 13  (see  FIG. 5 ). As seen most clearly in  FIG. 4 , the outer cutting diameter D 11  of the disk-saw  11  is preferably less than the inner diameter d 13  of the disk-saw  13 , so that the disk-saw  11  may be nested axially within the disk-saw  13  and may therefore be adjusted to extend axially beyond the disk-saw  13  any desired amount. For example, comparing  FIGS. 10A and 10B , the disk-saw  11  is shown in a first relative position ( FIG. 10A ) in which the disk-saw  11 , nested in the disk-saw  13 , extends axially beyond a front face “f” of the disk-saw  13  an amount “d 1 ” and a second relative position ( FIG. 10B ) in which the disk-saw  11  extends beyond the front face of the disk-saw  13  a lesser amount “d 2 ” while remaining nested within the disk-saw  13 . 
   In addition, also as best seen in  FIG. 4 , it is preferable that the diameter D 11 , of the disk-saw  11  is just slightly less than the inner diameter d 13  of the disk-saw  13 , so that the space available therebetween for conducting sawdust into the cutting head  10  is minimized. Preferably, the radial clearance between the nested disk-saws is no greater than about 0.020″, to minimize packing of sawdust between the disk-saws. 
     FIG. 11  illustrates still another aspect of the invention in which, preferably, the cutting head  10  is relieved such that there is an aperture  31  therethrough (also shown in  FIG. 6 ), and there is a route as shown at  32  behind at least the cutting teeth of the smaller diameter disk-saw  11  to the aperture  31 , for conducting sawdust entering the space between the disk-saws into the cutting head to the exterior of the cutting head. For example, even where the two cutting heads are nested together and the clearance between the outer cutting diameter D 11  ( FIG. 4 ) of the cutting head  11  and the inner diameter d 13  ( FIG. 5 ) of the cutting head  13  is essentially zero, sawdust may still enter the cutting head through the spaces between the cutting teeth  11   a . The reliefs  31  and  32  cooperate with the maximum radial clearance indicated above to minimize or prevent packing of sawdust around the disk-saws. 
   Referring back to  FIG. 2 , it may be noted that the log  14  may be curved, having a curved elongate axis  24 . In that circumstance, the heads  10  may all be moved together, upwardly or downwardly in the direction of the arrows, to follow the curvature of the log as it is fed along the direction of flow. This permits profiling a curved log according to the invention in such manner as to follow the grain, which optimizes the strength of the resulting lumber. The curved boards resulting from profiling the curved log may be straightened in subsequent processing with known techniques. 
   It is to be recognized that, while a particular adjustable profiling head for a wood cutting apparatus has been shown and described as preferred, other configurations and methods could be utilized, in addition to those already mentioned, without departing from the principles of the invention. 
   The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.