Abstract:
A wood cutter assembly includes a saw assembly, a slewing assembly and a skewing assembly. The saw assembly includes a cutter assembly rotated about a drive axis by a drive shaft passing through an open region therein. The cutter assembly includes a cutter mounted to a cutter spindle for rotation about the open region. The cutter assembly is mounted to a spindle housing, which is pivotally mounted to a saw positioner for movement about a pivot axis. The pivot axis passes through the drive shaft transversely to the drive shaft axis. The cutter is slewed so to move the saw positioner, and the spindle housing and cutter assembly therewith, along the drive shaft. The cutter is skewed relative to the drive shaft axis over a range of skew angles by selectively rotating the spindle housing, and the cutter assembly therewith, about the pivot axis.

Description:
CROSS-REFERENCE TO OTHER APPLICATIONS 
       [0001]    This application claims the benefit of provisional patent application number 61/087,416, filed 8 Aug. 2008, attorney docket number MGDC 1006-1, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Many trees do not grow straight so that the logs cut from the trees are swept or curved in shape. Special procedures and equipment must be used to maximize the board feet of lumber cut from these imperfect logs.  FIGS. 1A and 1B  illustrate two typical swept or curved logs  2 ,  3 .  FIG. 2  is an end view of log  2  showing how the swept or curved feature is typically in a single plane. To create lumber from log  2 , side boards  4 , illustrated in  FIG. 3 , are, in this typical example, cut from log  2  by making cuts along lines  6 ,  7  on either side of log  2  so that each side board  4  has parallel, cut surfaces  8 ,  9  and unfinished, uncut edges  10 ,  11 . These cuts are made in a conventional manner. What is left of log  2  is called a center cant illustrated as center cant  12  in  FIG. 4 . 
         [0003]    Center cant  12  has opposite, parallel, cut surfaces  14 ,  15  which correspond to surfaces  9  of boards  4  made at cutting lines  7 . The end  16  of center cant  12  in  FIG. 4  has a number of dashed cut lines  18  corresponding to where cant  12  will be rip sawn to create center cant lumber  20 . See also  FIG. 5 . To maximize the board feet of lumber from center cant  12 , cut lines basically parallel the edges  22  of center cant  12 . While the center cant lumber  20  will originally have the same curved or swept shape as center cant  12 , most, if not all, of this curve can be removed during drying operations. Side boards  4  are cut differently than center cant  12  to maximize the amount of side board lumber  24  as suggested in  FIG. 6 . Using conventional computer-controlled edger optimizing systems, the number, size and position of center cant lumber  20  and side board lumber  24  are determined automatically using appropriate computer programs based upon profile information of the side board  4  or center cant  12  scanned into the computer. 
         [0004]    For example, U.S. Pat. No. 4,239,072 discloses a method and apparatus for edge trimming a side board. A number of overhead pressure rolls engage the side board as the side board passes along a chain conveyor. The side board is centered by sets of centering rolls. A number of scanning gates are positioned above the conveyor to provide a computer with appropriate information on the profile of the side board. The edging assembly includes a pair of adjustable cutting heads designed to chip the unwanted edges from the side board. The cutting heads are slewed in a direction perpendicular to the direction of movement of the board by hydraulic cylinders so that one or more pieces of side board lumber can be cut from a single side board. 
         [0005]    U.S. Pat. No. 4,449,557, assigned to the same assignee as U.S. Pat. No. 4,239,072, uses substantially the same system for delivering partially cut logs to an edging assembly as the &#39;072 patent. However, instead of using angled edge chippers, as in the &#39;072 patent, the &#39;557 patent uses sawing disks or saw blades to make the edge cuts. The entire edger saw system moves as a unit so that the sawing disks can skew, that is change the angle between the axis of rotation of the sawing disks and the direction of feed of the work piece and can slew, that is move laterally along a line generally perpendicular to the direction of feed of the work piece. 
         [0006]    Some conventional edger optimizer systems measure the boards transversely and then position the board onto a feeding mechanism and move the board longitudinally into the edger. This conventional method requires a considerable amount of expensive scanning, positioning and transporting equipment to carry out the process. Conventional systems also commonly create cumulative scanning, positioning and transport errors that make the systems somewhat less than optimal. With regard to the &#39;557 patent, complex board centering mechanisms, multiple scanner heads, complex and high maintenance feeding and tracking devices, and complex high inertia edger rotation devices are all characteristic of the system described in the patent. 
         [0007]    U.S. Pat. No. 5,761,979 and U.S. Pat. No. 5,870,939 describe a saw assembly that includes a rotatable arbor on which two or more saw blades are mounted. The driving interface between the saw blades and the arbor permits the axis of rotation of the saw blades to be collinear with the arbor axis or skewed a few degrees in either direction. A saw blade positioning assembly includes pairs of guide arms which engage the sides of the saw blades to position each saw blade at the proper location along the arbor and at the proper skew angle. The guide arms are moved in unison so that the axial position and the skew angle of each of the saw blades can be changed in unison before and during sawing operations. 
         [0008]    In these designs, the guide arms that engage the sides of the rotating saw blades require constant maintenance and can often lead to problems. These saw guide arms require the use of saw blade lubricants and cooling water that reduce the fuel value of the saw dust and cause environmental and waste water concerns. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    A first aspect of the invention is directed to a saw assembly usable as part of a wood product sawing apparatus. A drive shaft is supported by a frame and is rotatable about a drive shaft axis, the drive shaft comprising a first drive feature, such as an axially extending spline surface in some examples. A cutter assembly includes a cutter rotatably mounted to a cutter spindle. The cutter assembly defines an open region through which the drive shaft passes. The cutter assembly comprises a second drive feature engaging the first drive feature so that rotation of the drive shaft rotates the cutter assembly while permitting the cutter assembly to slide along the drive shaft in the direction of the drive shaft axis. The open region, in some examples a tapered open region, is configured to permit the cutter to be oriented on the drive shaft over a range of skew angles relative to the drive shaft axis. The cutter spindle is rotatably mounted to and supported by a pivoting spindle housing for rotation of the cutter about the drive shaft axis. The pivoting spindle housing is rotatably mounted to a saw positioner body for rotation of the pivoting spindle housing and cutter assembly therewith about a pivot axis. The pivot axis passes through the drive shaft in a direction transverse to the drive shaft axis. A skewing driver is mounted to the saw positioner body and is drivingly connected to the pivoting spindle housing to move the pivoting spindle housing about the pivot axis thereby skewing the cutter relative to the drive shaft axis over at least part of the range of skew angles. A slewing positioner, supported by the frame and connected to the saw positioner body, is operable to move the saw positioner body and the pivotal spindle housing and cutter assembly therewith along the drive shaft axis. In some examples the cutter assembly, pivoting spindle housing and saw positioner body constitute a cutting unit and the saw assembly further comprises a plurality of the cutting units with the drive shaft passing through the open regions of the cutter assemblies of the saw positioners. 
         [0010]    A second aspect of the invention is directed to a wood cutter assembly, usable as part of a wood product sawing apparatus, including a saw assembly, a slewing assembly and a skewing assembly. The saw assembly comprises a cutter assembly having an open region, a drive shaft passing through the open region, a cutter spindle and a cutter mounted to the cutter spindle for rotation about the open region. The cutter assembly is mounted to a spindle housing. A saw positioner is supported by the frame. The spindle housing is pivotally mounted to the saw positioner for movement about a pivot axis. The pivot axis passes through the drive shaft transversely to the axis of the drive shaft. The slewing assembly, used to move the cutter along the drive shaft, comprises a saw positioner driver assembly engaging the saw positioner to move the saw positioner in a direction parallel to the drive shaft axis so the spindle housing and cutter assembly therewith move along the drive shaft. The skewing assembly, for moving the cutter relative to the drive shaft axis over a range of skew angles, comprises a spindle housing rotator assembly pivotally driving the spindle housing and the cutter assembly therewith about the pivot axis. The cutter assembly, spindle housing and saw positioner may be considered to constitute a cutting unit. Some examples comprise plurality of the cutting units with the drive shaft passing through the open regions of the cutter assemblies. In some examples separate saw positioner driver assemblies engage the saw positioner for each of the cutting units. In some examples one spindle housing rotator assembly pivotally drives the spindle housings and the cutter assemblies therewith about respective pivot axes for all of the cutting units. 
         [0011]    A third aspect of the invention is directed to a method for slewing and skewing a wood cutter of a saw assembly, the saw assembly usable as part of a wood product sawing apparatus. A cutter assembly is rotated about a drive shaft axis by a drive shaft passing through an open region in the cutter assembly. The cutter assembly includes a cutter spindle and a cutter mounted to the cutter spindle for rotation about the open region. The cutter assembly is mounted to a spindle housing. The spindle housing is pivotally mounted to a saw positioner for movement about a pivot axis. The pivot axis passes through the drive shaft transversely to the drive shaft axis. The cutter is slewed along the drive shaft axis so to move the saw positioner, and the spindle housing and cutter assembly therewith, along the drive shaft. The cutter is skewed relative to the drive shaft axis over a range of skew angles by selectively rotating the spindle housing, and the cutter assembly therewith, about the pivot axis. In some examples a plurality of the cutter assemblies are rotated about the drive shaft axis. In some examples the slewing step is carried out by independently selectively moving the saw positioners. In some examples the skewing step is carried out by selectively rotating all of the spindle housings in unison. 
         [0012]    Other features, aspects and advantages of the present invention can be seen on review the figures the detailed description, and the claims which follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIGS. 1A and 1B  are overall views showing two different types of curved or swept logs; 
           [0014]      FIG. 2  is an end view of the log of  FIG. 1A  taken along line  2 - 2 ; 
           [0015]      FIG. 3  is an enlarged view showing a side board cut from the log of  FIG. 2 ; 
           [0016]      FIG. 4  is an enlarged view showing a center cant cut from the log of  FIG. 2 ; 
           [0017]      FIG. 5  is a simplified top plan view of the center cant of  FIG. 4  illustrating dashed cut lines and the resulting center cant lumber to be cut from the center cant; 
           [0018]      FIG. 6  is a simplified top plan of the side board of  FIG. 3  illustrating the outlines of side board lumber to be cut from the side board of  FIG. 3 ; 
           [0019]      FIG. 7  is a simplified top plan view of an example of a sawing apparatus made according to the invention; 
           [0020]      FIG. 8  is a simplified side view of the apparatus of  FIG. 7 ; 
           [0021]      FIGS. 9 and 10  are enlarged front elevation and top plan views of a portion of the saw assembly of  FIGS. 7 and 8  showing a set of three saw positioners and associated saw blades with the saw blades at a 2° cant; 
           [0022]      FIG. 11  is an enlarged front, right side, top isometric view of a portion of the structure of  FIGS. 9 and 10 ; 
           [0023]      FIG. 12  is a front, left side isometric view of the structure of  FIG. 11 ; 
           [0024]      FIGS. 13 and 14  are top and front views of the structure of  FIGS. 11 and 12 ; 
           [0025]      FIG. 15  is a somewhat simplified cross-sectional view taken along line  15 - 15  of  FIG. 14 ; 
           [0026]      FIG. 16  is an enlarged cross-sectional view of a portion of the structure of  FIG. 14  taken through the skewing drive shaft; 
           [0027]      FIG. 17  is an enlarged isometric view of the structure of  FIG. 16  with portions removed to show the engagement of the steering pin roller within the corresponding steering cam profile slot of the steering cam; 
           [0028]      FIG. 18  is an enlarged view of a portion of the structure of  FIG. 11  showing the engagement of the teeth of the spindle drive plate with the spline drive shaft  18 ; 
           [0029]      FIG. 19  is an enlarged rear cross-sectional view of a portion of the structure of  FIG. 14  showing the tapered opening in the saw spindle through which the spline drive shaft passes to accommodate skewing of the saw blade; and 
           [0030]      FIG. 20  is an isometric cross-sectional view of the structure of  FIG. 19 . 
       
    
    
     LIST OF REFERENCE NUMERALS 
       [0000]    
       
           2  Curved Log 
           3  Curved Log 
           4  Side Boards 
           6  Cut Lines 
           7  Cut Lines 
           8  Cut Surfaces 
           9  Cut Surfaces 
           10  Uncut Edges 
           11  Uncut Edges 
           12  Center Cant 
           14  Opposite, Parallel, Cut Surfaces 
           15  Opposite, Parallel, Cut Surfaces 
           16  End of Center Cant 
           18  Dashed Cut Lines 
           20  Center Cant Lumber 
           22  Edges of Center Cant 
           24  Side Board Lumber 
           26  Chipped Face of Center Cant 
           30  Sawing Apparatus 
           32  Infeed Assembly 
           34  Infeed Lug Chain 
           36  Partially Cut Log 
           38  Canted Drive Rolls 
           40  Fence 
           41  Longitudinal or Forward Direction 
           42  Lateral or Infeed Direction 
           44  Scanning Conveyor 
           46  Scanning Assembly 
           48  Scanner 
           50  Controller 
           52  Cutting Assembly 
           54  Pressroll Assembly 
           56  Saw Assembly 
           58  Driven Feed Chain 
           60  Pivotal Press Rolls 
           62  Drum Reman Head 
           64  Driven Exit Rolls 
           66  Sawn Lumber 
           68  Discharge Assembly 
           70  Paddle Picker Outfeed 
           72  Cutter Assembly 
           74  Saw Spindle 
           75  Saw Blades 
           76  Saw Positioner 
           78  Skewing Assembly 
           80  Saw Blade Slewing Assembly 
           82  Saw Positioner Body 
           84  Pivoting Spindle Housing 
           85  Fasteners 
           86  Spindle Bearings 
           87  Clamping Collar 
           88  Annular Side Surface of Saw Blade 
           89  Saw Spindle Drive Plate 
           90  Saw Shift Axis 
           91  Teeth of Spindle Drive Plate 
           92  Vertical Pivot Axis of  84   
           93  Spline Drive Shaft 
           94  Skewing Angle 
           95  Rotation Axis of  93   
           99  Spindle Rotation Axis 
           101  Rotation Axis of Fixed Drive Source 
           114  Skewing Positioner 
           116  Skewing Drive Shaft 
           118  Bell Crank Arm 
           117  Sliding Steering Cam Assembly 
           119  Pivot Bearings 
           120  Steering Arm Retainer 
           121  Thrust Washers 
           123  Skewing Cam Retainer 
           124  Steering Cam 
           125  Steering Pin Roller 
           126  Linear Bearings 
           128  Saw Assembly Frame 
           130  Steering Arm 
           131  Fixed Drive Source 
           132  Steering Pin 
           133  Steering Cam Bushing 
           136  Linear Positioner 
           140  Outer Bearing Retainer 
           141  Feed Path 
           142  Inner Bearing Retainer 
           143  Anti-Collision Pad 
           144  Steering Cam Profile Slot 
           166  Shift Shaft 
           167  Dummy Shift Shaft 
           168  Openings in  82  for  166   
           170  Support Shaft 
           172  Openings in  82  for  170   
           174  Tapered Opening in  74   
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0120]    The following description will typically be with reference to specific structural embodiments and methods. It is to be understood that there is no intention to limit the invention to the specifically disclosed embodiments and methods but that the invention may be practiced using other features, elements, methods and embodiments. Preferred embodiments are described to illustrate the present invention, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a variety of equivalent variations on the description that follows. Like elements in various embodiments are commonly referred to with like reference numerals. 
         [0121]    The present invention is directed to a wood product assembly, such as an improved saw assembly for an edge trimming and board ripping apparatus, and method which provides a greatly simplified approach to, for example, optimally edging and ripping boards. 
         [0122]    The edge trimming and board ripping apparatus includes an improved saw assembly used as a part of a sawing apparatus. The sawing apparatus, in one example, includes an in-feed assembly which delivers side boards or center cants one at a time to a scanning assembly. The side boards and center cants both have two parallel cut surfaces and are referred to generically as partially cut logs, cut logs or just logs. The scanning assembly preferably includes a scanner adjacent to a scanning conveyor. The scanner scans the cut log and provides a profile of the log to a computer which controls the operation of the improved saw assembly. The saw assembly is preferably part of a cutting assembly. The cutting assembly typically includes a press roll assembly which maintains the cut log in the same orientation, passing through the saw assembly, as the cut log had when it passed the scanner. 
         [0123]    A saw assembly  56 , see  FIGS. 7-12 , includes two or more cutter assemblies  72 . In this example each cutter assembly  72  comprises a saw blade  75  and a saw spindle  74 . Three cutter assemblies  72  are shown in  FIGS. 9 and 10 . Each saw blade  75  is individually supported, positioned and driven by subcomponents of saw assembly  56  as follows. Each saw blade  75  is rigidly attached to saw spindle  74 . Each saw spindle  74  and saw blade  75 , connected and rotating together, is mounted in a pivoting spindle housing  84 . The pivoting spindle housing  84  contains spindle bearings  86  (see  FIGS. 15 and 19 ) that allow free rotational movement of the saw spindle  74 . Each pivoting spindle housing  84  is pivotally mounted to a saw positioner body  82  of a saw positioner  76  through a steering arm  130 . See  FIGS. 12 and 15 . The combination of cutter assembly  72 , spindle housing  84  and saw positioner body  82  is sometimes referred to in this application as a cutting unit. Steering arm  130  is mounted to pivoting spindle housing  84  by fasteners  85 . Steering arm  130  includes a support shaft  170  passing upwardly through a corresponding opening  172  formed in saw positioner body  82  along a vertical pivot axis  92 . Steering arm  130  is retained in place by a steering arm retainer  120 . Thrust washers  121  are positioned at either end of opening  172  between corresponding surfaces of saw positioner body  82 , steering arm retainer  120  and the main body of steering arm  130 . 
         [0124]    Each saw positioner body  82  supports a pivoting spindle housing  84  through steering arm  130  while allowing the spindle housing to turn at a slight angle about vertical pivot axis  92  to facilitate saw skewing (typically approximately ±5 degrees) through the use of two pivot bearings  119  as shown in  FIGS. 15 and 17 . The saw positioner  76  also shifts (repositions) positioner body  82  in a linear motion at a right angle (or transversely) to the log&#39;s direction of travel or feed path  141  to provide the required slewing movement of the saw blade/saw spindle assembly during saw operation. 
         [0125]    Each saw spindle  74  is coupled to and rotatable driven by a splined spindle drive plate  89  engaging a spline drive shaft  93  as shown in  FIG. 18 . The engagement clearance (typically 0.025″) between the female spline of the spindle drive plate  89  and the male spline of the spline drive shaft  93  is sufficient to allow the spindle drive plate to be skewed, that is to rotate about vertical pivot axis  92  approximately ±5 degrees. As seen in  FIGS. 19 and 20 , spindle  74  has a tapered opening  174  to permit this skewing without binding. Spline drive shaft  93  is coupled to a drive source  131 ; drive source  131  is typically fixed. Examples of drive source  131  include a fixed motor  131  or a fixed drive shaft coupled to a remote drive motor  131 . The axis of rotation  101  of drive source  131  is preferably at a right angle to the log&#39;s direction of travel  14 land generally parallel to the saw shift axes  90  (see  FIGS. 10 ,  11  and  12 ). 
         [0126]    The spindle drive plate  89  transmits torque to the saw spindle  74  while allowing both: (1) the axis of rotation of the saw spindle to turn at an angle relative to the axis of rotation of the spline drive shaft  93 , that is skew, and (2) the saw spindle to move closer to or further away from drive source  131 , that is slew. 
         [0127]      FIGS. 9 and 10  show an embodiment of a saw assembly when composed of 3 saw blades. In this example three shift shafts  166  and one dummy shift shaft  167  support and position each saw positioner  76 . Shift shaft  166  and dummy shift shaft  167  pass through openings  168  in saw positioner body  82  (see  FIG. 12 ). Dummy shift shaft  167  would be replaced by a shift shaft  166  if a fourth saw positioner  76  were to be used. Each body  82  of each saw positioner  76  is rigidly connected to one of its shift shafts  166  and slides on the others. The three shift shafts  166  and the dummy shift shaft  167  that support the saw positioners are supported on each end by the saw assembly frame  128  (see  FIG. 9 ). Linear positioners  136 , see  FIGS. 9 and 10 , located outside and connected to the saw assembly frame  128 , are coupled to each shift shaft  166  and individually actuate each shift shaft to provide the required saw positioning and slewing motion for each saw blade  75  along each saw shift axis  90  during saw operation. Linear bearings  126 , see  FIGS. 9 and 10 , are used where the shift shafts  166  intersect the saw assembly frame  128  to provide the proper guidance and support. 
         [0128]    In this embodiment, a skewing drive shaft  116 , see  FIGS. 11 and 17 , is used to skew the saw blade/saw spindle assembly  74 ,  75  during saw operation. Skewing drive shaft  116  extends parallel to saw shift axes  90  (see  FIG. 9 ). A single skewing positioner  114  actuates the rotation of the skewing drive shaft. The skewing drive shaft  116  is linked to the pivoting saw spindle housing  84  through a sliding steering cam assembly  117  (see  FIGS. 15-18 ) including a steering cam  124  rotating in bushing  133  in saw positioner  82 . Steering cam assembly  117  is coupled to steering arm  130  through steering pin  132  and roller  125  engaging steering cam profile slot  144 . Pivoting spindle housing  84  attaches to steering arm  130  with fasteners  85 . The sliding steering cam assemblies  117  move along the skewing drive shaft  116  because they are captivated in the saw positioner bodies  82  by retainer plates  123  (following the slewing motion of the saw positioner  76  specific to each saw blade  75 ) and also rotate with the skewing drive shaft  116  (through a splined or keyed connection). The sliding steering cam assembly  117  is connected by steering pin  132  and roller  125  to the steering arm  130 . Steering arm  130  is rigidly connected to the pivoting spindle housing  84  by fasteners  85 . Therefore, rotation of skewing drive shaft  116  by skewing cylinder  114  rotates sliding steering cam assembly  117  which drives roller  125  along steering cam profile slot  144  causing steering arm  130  and spindle housing  84  therewith to pivot about axis  92  to provide the required saw blade skewing or angular motion. 
         [0129]    With the present invention, side board lumber can be cut from side boards by edge trimming the side board and, optionally, rip sawing the side board to create one or more pieces of side board lumber. Also, center cants can be simultaneously edge trimmed and rip sawed to create center cant lumber from the center cant using the saw assembly made according to the invention. 
         [0130]    One of the primary advantages of the invention is its simplicity. The partially cut log  36  need not be centered on the scanning conveyor  44  or the feed chain  58  of the press roll assembly  54  but rather simply placed somewhere on the scanning conveyor. Therefore, no centering rolls, as are used with conventional edger systems, are needed. Also, the present invention is designed to be used with only a single scanner, as opposed to the multiple scanners used with conventional systems, thus reducing cost. In addition, the present invention is adapted for use for both edge trimming and board ripping of both side boards and center cants making it very flexible. 
         [0131]    An additional advantage is that the saw blade slewing assembly  80 , which includes linear positioners  136 , shift shafts  166  and linear bearings  126 , is used to both initially position the saw positioners  76  and saw blades  75  therewith at the desired locations as well as slew, in unison, the saw blades while sawing the log. Also, the same structure, that is saw positioner  76 , used to laterally position the saw blades is used to keep the saw blades at the proper skewing angle. Thus, of the actual sawing components (motor  131 , arbor  93 , saw blades  75 , support frame  128 ), the only components which must move during sawing operations are the saw blade positioner assemblies  76 ; the electric motor  131 , or other drive source, which drives the saw spindles  74  as well as the support frame  128  which supports the motor and spindle assemblies, can remain stationary. The complicated slewing and skewing schemes used with conventional edger systems are eliminated. 
         [0132]    Another advantage of the invention is that the saw blades  75  require no guide arms to provide the positioning and stabilization. The use of saw guide arms adds complexity to the sawing system along with requiring constant maintenance. The sawing accuracy of the invention is higher than with a system using saw guide arms because of the rigid mounting of the saw assembly. The guide arms require a complex lubricating and cooling system to properly guide, position and stabilize the saw blades. The use of this saw blade lubricating and cooling system increases operating cost and causes the saw dust to be wet reducing its value as a fuel. Excess saw blade cooling water can find its way into storm drains, streams and rivers and cause environmental damage and well as contaminate ground water. 
         [0133]    The above descriptions may have used terms such as above, below, top, bottom, over, under, et cetera. These terms are used to aid understanding of the invention are not used in a limiting sense. 
         [0134]    While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims. For example, the proportions and numbers of center cant  12 , center cant lumber  20 , side boards  4 , and side board lumber  24  illustrated in  FIGS. 2-6  are simply one example for one particular log  2 ; some logs may produce no side board lumber. Different configurations of the invention can be used to allow varying numbers of saw blade positioners  76 . Various types of cutters, such as wood chippers, can be used instead of or in addition to saw blades  75 . 
         [0135]    Any and all patents, patent applications and printed publications referred to above are incorporated by reference.