Abstract:
A scraper plane used in woodworking and providing a blade having an adjustable angle as well as adjustable camber. Varying the camber of the blade creates various sized regions of contact between the cutting edge of the blade and the workpiece. Variable camber provides increased control and improved function.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to U.S. Provisional Patent Application Ser. No. 60/494,238 filed Aug. 11, 2003 entitled “Scraper Plane,” which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to scraper planes used in woodworking. 
   BACKGROUND 
   Edge tools called “scrapers” have long been used in woodworking for removing thin shavings of wood or finish from a workpiece. Scrapers have been used freehand and in a variety of holders such as disclosed in U.S. Pat. No. 5,459,928. Some such prior scraper holders have a sole that contacts the workpiece. 
   SUMMARY 
   An improved scraper plane according to this invention includes a blade having an adjustable angle as well as adjustable camber. The blade is captured between the frog and lever cap, and is held in position by a lever cap screw. The frog includes an aperture adapted to receive a camber screw. The end of the camber screw bears against the blade near the cutting edge of the blade. The camber screw may be adjusted to introduce camber in the blade. 
   It is therefore one feature of this invention to provide variable blade camber to create various sized regions of contact between the cutting edge of the blade and the workpiece. 
   It is another feature of this invention to provide variable blade camber in order to provide increased control and improved function. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the scraper plane of this invention showing the top and left side. 
       FIG. 2  is a side elevation view in partial cross-section of the scraper plane shown in  FIG. 1 . 
       FIG. 3  is an exploded perspective view of the scraper plane shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   As may be seen by reference to  FIGS. 1-3 , the scraper plane  10  of this invention includes generally a plane body or casting  14 , a knob  16  at the front of the plane body  14 , and a handle or tote  18  at the rear. Threaded rods  20  are received in handle bores  22  and pass through the handle  18  to thread into handle base  24 . Knob nuts  26  attach to the other end of rods  20 , so that handle  18  is attached to the body  14 . 
   Blade  28  is captured between frog  30  and lever cap  32 , and is held in position by lever cap screw  34 , which is threaded into lever cap screw aperture  31  in lever cap  32  to contact and exert pressure against blade  28 . Lever cap pivot screws  35  pass through lever cap bushings  36  into apertures  38  in wings  40  of frog  30  and into side apertures  42  of lever cap  32 , securing lever cap  32  to frog  30  so that lever cap  32  can pivot. Frog cap screws  44  and bushings  46  pass through apertures  48  in the side of body  14  and are received in threaded apertures  50  in frog  30 , pivotally securing frog  30  to body  14 . 
   Upstanding brace  52  protruding from body  14  behind the mouth  53  is penetrated by brace aperture  54 , which receives adjustment stem  56 , which passes through brace aperture  54  and is received in threaded aperture  62  of adjustment pin  64  that is pivotably positioned in arms  70  on the backside  65  of frog  30 . Adjustment nuts  60  bear against brace  52  to control the protrusion of stem  56  and thereby control the angle of frog  30  and blade  28  relative to the sole of body  14 . Cone point set screw  66  threaded into one end of pin  64  secures adjustment stem  56 , which has a reduced diameter end  67  of adjustment stem  56  that is threaded into pin  64 . Pin  64  passes through arm apertures  68  of arms  70 , which project from frog  30 . Adjustment nuts  60  control the angle of the blade  28 . 
   Camber screw  72  with a knurled head  73  is received in camber aperture  74  of frog  30  near cutting edge  76  of blade  28 , and the end  75  of screw  72  can bear against blade  28  relatively near its cutting edge  76 . Camber screw  72  may be adjusted to introduce curvature, or camber, in blade  28 . Adjusting the geometry of the blade  28  using camber knob  72  allows adjustment of the amount and shape of the blade surface that contacts the workpiece. For example, increasing the camber of the blade creates a smaller contact region of cutting edge  76  with the workpiece, while decreasing the camber increases the workpiece contact region of edge  76 . This ability to adjust blade camber affords substantially more control over the cutting characteristics of the scraper plane, significantly improving its function. In alternative embodiments, camber may be adjusted using a wedge, a lever, or any other suitable mechanism rather than the screw  72  depicted in the figures. 
   Camber screw  72  may have any alternative head configuration, including a slotted head, phillips head, hex head, allen head, or any other suitable configuration. In one alternative embodiment, a camber screw is inserted into the opposite side of the frog aperture, so that the head of the camber screw bears against the blade after the blade is positioned between the frog and the lever cap. In another alternative embodiment, non-adjustable camber may be introduced using a protrusion or knob on the frog or by using a frog having a curved blade contacting surface, or by any other suitable configuration. 
   Threaded knob rod  78  passes through bore  80  in front knob  16  and is received in front knob base  82 . The upper end of threaded knob rod receives knob nut  84 , securing front knob  16  to the body  14 . 
   All variations of the structures illustrated in the drawings and the materials described above are within the scope and spirit of this invention and the following claims.