Patent Publication Number: US-2005126361-A1

Title: Motorized wood working tool having a low friction table

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to motorized woodworking tools having a low friction surface for supporting a workpiece to be cut.  
      2. Background Art  
      Motorized wood working tools, both floor mounted or bench types are frequently provided with a generally horizontal table surface to support a wooden work piece to be cut. Representative tools having a planar table top include scroll saws, table saws, band saws, surface planers, joiner planers, belt sanders, disc sanders, router tables, jig saw base plates and miter saw tables. Common to all of these motorized wood working tools is the presence of a generally flat horizontal table top which the user supports a workpiece to be cut by a motor driven cutting element such as a saw blade. Frequently, particularly when making a precise free hand cut using a scroll saw or a band saw, it is highly desirable to minimize the friction between the workpiece and the table top so that the pattern marked on the workpiece can be closely followed. On circular table saws where cutting normally takes place using a fence, it is still desirable to minimize friction between the workpiece and the table so that the workpiece can be smoothly fed relative to the cutting element at a constant speed without sticking and bonding.  
      Traditionally, the table top of a motorized woodworking floor mounted or bench top tool would be a metal plate having a generally flat planar surface which is then machined flat when used in the “as machined” state. In the case of scroll saws and small light duty band saws, the table top will be frequently formed of an aluminum die casting. In such instances, the table top is machined flat and often coated with a clear finish in order to prevent corrosion and staining. Even with this clear coat applied to the machine table top, friction levels between the workpiece and the table top are higher than desired.  
     SUMMARY OF THE INVENTION  
      Accordingly, the motorized woodworking tool of the present invention is provided with a base having a metal table top having a generally planar workpiece support surface with an opening formed therein. The tool further includes a motor which drives a cutting element oriented to extend through the opening in the workpiece support surface. A surface layer is applied directly to the workpiece support surface of the metal table top to create a low friction surface for cooperating with a workpiece placed thereon for sliding contact relative to the surface layer during cutting. The invention is suitable for use with scroll saws, table saws and band saws where the workpiece is slid across the support surface relative to the cutting blade during use. Preferably, the metal table top is formed of cast iron, die cast aluminum or cast aluminum. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a motorized woodworking tool having a low friction table top in accordance with the present invention;  
       FIG. 2  is a cross-sectional view of a wing of the planar workpiece support surface of  FIG. 1  along line  2 - 2  having a low friction surface layer applied thereon;  
       FIG. 3  is a scroll saw having a low friction table top in accordance with another aspect of the present invention; and  
       FIG. 4  is a band saw having a low friction table top in accordance with yet another aspect of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
      Referring now to Figures, a motorized woodworking tool having a low friction table for supporting a workpiece during a cutting operation is shown.  FIGS. 1 and 2  illustrate a table saw  10  providing a first embodiment of the claimed invention. Table saw  10  is provided with a base  12  having a motor (not shown) located internally thereto which drives a circular rotary cutting blade  14 . Blade  14  extends through a slot  16  in a metal table top  18 .  
      A pair of generally planar table wings  20  and  22  which likewise have a flat, generally planar surface are provided coplanar to the metal table top  18 , forming a generally flat planar workpiece support surface  24 . Table top  18  and wings  20 ,  22  are formed from a cast metal such as die cast aluminum, cast iron or the like. Referring additionally to  FIG. 2 , a surface layer  26  is applied to the top surface  28  of at least one of wings  20 ,  22  and table top  18 . Surface layer  26  preferably comprises a plastic laminate, such as Formica, which provides a uniform, low friction, highly durable surface cooperating with a workpiece placed thereon to be cut by a user with the rotary cutting blade  14 . It is understood that the each wing  20 ,  22  and the table top  18  may be covered with a plastic laminate surface layer  26  to reduce friction between the planar workpiece support surface  24  and the workpiece.  
      In one aspect of the invention, the surface layer  26  is bonded to the unfinished top surface  28  of each wing  20 ,  22  of the table saw  10 , reducing the overall production costs. Alternatively, the top surface  28  of wing  22  may be machined flat similar to table top  18  prior to the application of the surface layer  26  to improve the bonding characteristics between the surface layer  26  and wing  22 . Surface layer  26  is relatively is thin, between {fraction (1/32)} and {fraction (1/16)} inch in thickness, and is supported by the top surface  28  of wing  22 .  
      Plastic laminates are firm, highly resistant to scratching and easy to clean after use. The plastic laminate surface layer  26  of workpiece support surface  20  exhibits low, friction, non-stick characteristics, enabling the workpiece to be freely moved relative to the cutting blade  14 . If desired, a plastic laminate surface layer may be applied to the movable fence  29  to provide a low friction surface for engaging a workpiece to be cut on the table saw  10 .  
       FIG. 3  illustrates a scroll saw  30  illustrating another aspect of the claimed invention. Scroll saw  30  is provided with a base  32  having a metal table top  34  pivotally mounted thereto in a conventional manner. Metal table top  34  is provided with a generally planar work support surface  36  having an opening  38  extending therethrough. A motor  40  is attached to base  32  and operatively connected to a saw blade  42  which is affixed to a pair of blade holders; upper blade holder  44  and a similar blade holder not shown located below the underside of the table top  34  in a conventional manner. During operation, motor  40  causes elongate blade  42  to oscillate vertically relative a workpiece placed on the planar workpiece support surface  36  to be slid relative to the blade during cutting.  
      Workpiece support surface  36  includes a surface layer  46  applied to the metal table top  34 . As described above, surface layer  46  is preferably a plastic laminate, such as formica, which exhibits low, friction, non-stick characteristics, enabling the workpiece to be freely moved relative to the saw blade  42 . It is also understood that the extension table  48  of scroll saw  30  may be covered with a plastic laminate surface layer in accordance with the present invention.  
      Another aspect of the motorized woodworking tool of the present invention is illustrated in  FIG. 4 . A band saw  50  is provided with a base  52  having a tiltable metal table top  54  with a generally planar work support surface  56 . The table top  54  is further provided with an aperture  58  extending therethrough to receive band saw blade  60 . Band saw blade  60  is a traditional, endless loop type blade which is entrained about a pair of wheels  62  and  64  shown in phantom outline above and below the metal table top  54  as illustrated.  
      Motor  66  is operatively connected to one of the wheels, preferably, lower wheel  64 , to cause the blade to move in an oval path with the exposed portion of the blade above metal table top  54 , moving downward toward the planar workpiece support surface  56 . As in the other described aspects of the invention, planar workpiece support surface  56  includes a plastic laminate surface layer  68  applied to the metal table top  54  to reduce friction between the workpiece and the surface layer  68  to be freely moved relative to the saw blade  60 .  
      While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention, for example the invention can be used with scroll saws, table saws, band saws, surface planers, joiner planers, belt sanders, disc sanders, router tables, jig saw base plates and miter saw tables. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.