Abstract:
A method and apparatus for cutting rigid, brittle articles such as tile used as a building material is improved by the capability to make both straight and curved cuts in tile on a single machine. The machine has both circular and plunge cutting tools and a table for moving the tile in both curved and straight lines in relation to the cutting tool, thereby achieving both curved and straight cuts.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/393,774, filed 15 Oct. 2010. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention is an improved method and apparatus for cutting rigid, brittle articles such as tile used as a building material, the improvements including having the capability to make both straight and curved cuts in tile on a single machine. The machine has both circular and plunge cutting tools and a table for moving the tile in both curved and straight lines in relation to the cutting tool, thereby achieving both curved and straight cuts. 
       BACKGROUND 
       [0003]    Ceramic tile is an example of a planar, rigid, brittle material used as a functional and decorative building material. Other types of generally planar rigid, brittle articles used as building materials include glass and glass-like materials, granite and artificial rock-like materials, and other materials such as concrete or other settable materials. These materials are generally manufactured as sheets or evenly sized squares or shapes that can be applied to a prepared structure to create a hard, decorative surface such as a floor or counter. An issue which applies to all such materials is a need to cut the shape or sheet to fit a particular area or shape on the prepared structure. 
         [0004]    The need to fixture tile for cutting with a power saw has been recognized. U.S. Pat. No. 6,508,244 B2, issued Jan. 21, 2003 to inventor Wy Peron Lee, discloses a table with guides for holding tile to be cut with straight cuts. U.S. Pat. No. 5,832,913, issued on Nov. 10, 1998 to inventor William R. Arends, discloses an improved table for cutting tile that permits tiles to be cut along straight lines at angles which may not be parallel to one of the sides of the tile.  Neither of these discloses a means for cutting tile with curved cuts. U.S. Pat. No. 4,061,126, issued on Dec. 6, 1977 to inventor Ronald F. Schlangen, discloses a band saw arrangement for sawing tile with a circular silicon carbide blade. While this arrangement is capable of making curved cuts, the size and shape of the cut is determined by freehand control of the article on the saw. Likewise, U.S. Pat. No. 6,152,127, issued on Nov. 28, 2000 to inventors Michael D. Fuhrman and Dana E. Fuhrman, discloses a router attached to a table with linear motion capable of making straight cuts or freehand curves. 
       SUMMARY 
       [0005]    What none of the patents cited above disclose is a means for fixturing a tile or other brittle, rigid, planar building material in a machine that will permit a power saw to cut both straight lines or curves with a specified radius. What is needed then is a machine that permits tile to be cut in both straight lines and curves of specified radius with a single power saw on a single table. 
         [0006]    Aspects of this invention improve making straight cuts, curved cuts with specified radius and freehand curves in articles such as building tile with a power saw. The power saw has a table and a saw, with the saw operative to use both circular blades and plunge cutters. The table is provided with both linear and rotary stages, arranged so that a workpiece such as building tile can be moved in both a linear and rotary fashion with respect to the saw blades. The saw is fitted with a rotatable bearing to hold a circular blade perpendicular to the workpiece. By then moving the workpiece with the linear stage, a straight cut is achieved. When a plunge cutter is fitted to the saw, the rotatable bearing is rotated to hold the plunge cutter perpendicular to the workpiece. By moving the workpiece with the rotary stage, a curved cut is achieved. 
         [0007]    Aspects of this invention accomplish compound motion necessary for cutting complex shapes in building materials by combining a linear stage with a rotary stage to hold the workpiece. The rotary stage is mounted on the linear stage by a rotary stage bearing. Either of the stages may be locked to prevent it from moving if purely linear or rotary motion is desired. These stages move a workpiece in relation to an electric saw which is positioned with respect to the table and stages radially on an arm that also pivots. The power saw is connected to a saw bearing that pivots on an axis perpendicular to the axis of rotation of the saw to permit the use of both circular and plunge type blades. The saw bearing is connected to an arm bearing that moves radially along the arm. The entire power saw assembly including the saw, the saw bearing, the arm bearing and the arm is moved up and down and rotated by the arm lift/bearing to move the blades up and down in relation to the surface of the workpiece. The arm lift/bearing, the arm bearing and the motor bearing may be adjusted or positioned manually or with assistance such as gearing, hydraulics or motors. These bearings are fitted with appropriate locks or other ways of preventing movement when desired and appropriate markings, scales, detents or other methods of aligning the various parts. 
         [0008]    In operation, aspects of this invention perform straight cuts in brittle building materials by fitting a circular blade to the power saw and rotating the saw bearing to make the circular blade parallel to the direction of travel of the linear stage and then positioning the circular blade laterally and vertically with respect to the workpiece. The rotary stage is locked and the workpiece is then moved into the circular saw blade with the linear stage to achieve a straight cut. Curved cuts are performed by first fitting the saw with a plunge type blade. The saw is rotated on the saw bearing to make the plunge type blade perpendicular to the surface of the workpiece. The blade is positioned in cooperation with the linear stage to place the blade in relation to the center of rotation of the rotary stage and the linear stage locked. This permits cutting arcs of arbitrary radius. The workpiece is then positioned on the rotary stage and the plunge type blade is lowered by the arm lift/bearing into the brittle material, cutting an arc as the workpiece is rotated under the blade by rotating the rotary stage. In a like manner, freehand shapes may be cut in brittle materials with a plunge type blade by moving both the rotary and linear stages simultaneously. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a tile cutting device. 
           [0010]      FIG. 2  is a plan view of the tile cutting device of  FIG. 1  set for a straight cut. 
           [0011]      FIG. 3  is a plan view of the tile cutting device of  FIG. 1  set for an arcuate cut. 
           [0012]      FIG. 4   a  is a plan view of a tile with straight cut. 
           [0013]      FIG. 4   b  is a plan view of a tile with curved cut. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Embodiments of this invention are an improved method for cutting both straight cuts and curved cuts with specified radius in brittle building materials with a power saw.  FIG. 1  shows a power saw  10  having a table  12  and a saw  14 , with the saw operative to use both circular blades  16  and plunge cutters  18  (see  FIG. 3 ). The table  12  is provided with both linear  20  and rotary  22  stages, arranged so that a workpiece such as a building tile  50  can be moved in either a linear or rotary fashion with respect to the saw blade  16 . The saw  14  is held in place by a rotatable bearing  40  to position a circular blade  16  perpendicular to the workpiece and parallel to the direction of travel of the linear stage  20 . By then moving the workpiece  50  to intersect the circular blade  16  with the linear stage  20 , straight cuts are performed. When fitting the saw with a plunge cutter  18 , the rotatable bearing  40  is rotated to hold the plunge cutter  18  perpendicularly to said workpiece. Then, moving the workpiece with the rotary stage  22  achieves a curved cut. 
         [0015]    Aspects of this invention achieve compound motion necessary for cutting complex shapes  28 ,  30  in building materials by combining a linear stage  20  with a rotary stage  22  that holds the workpiece. The rotary stage  22  is mounted on the linear stage  20  by a rotary stage bearing  32 . Either of the stages  20 ,  22  may be locked to prevent it from moving if purely linear or rotary motion is desired. These stages  20 ,  22  move a workpiece in relation to a power saw  14  which is positioned with respect to the frame  12  and stages  20 ,  22  radially on an arm  34  that also pivots. The power saw  14  is connected to a saw bearing  40  that pivots on an axis perpendicular to the axis of rotation of the saw to permit the use of both circular and plunge type blades  16 ,  18 . The saw bearing  40  is connected to an arm bearing  38  that moves radially along the arm  34 . The entire power saw assembly including the saw  14 , the saw bearing  40 , the arm bearing  38  and the arm  34  is moved up and down and rotated by the arm lift/bearing  36  to move the blades  16 ,  18  up and down in relation to the surface of the workpiece. The arm lift/bearing  36 , the arm bearing  38  and the motor bearing  40  may be adjusted or positioned manually or with assistance such as gearing, hydraulics or motors. These bearings  36 ,  38 ,  40  are fitted with appropriate locks or other ways of preventing movement when desired and appropriate markings, scales, detents or other methods of aligning the various parts. 
         [0016]    Aspects of this invention perform straight cuts in brittle building materials by fitting a circular blade  16  to the power saw  14  and rotating the saw bearing  40  to make the circular blade  16  parallel to the direction of travel of the linear stage  20  along rails  26  and then positioning the circular blade  16  laterally and vertically with respect to the workpiece  50 . The rotary stage  22  is locked and the workpiece  50  is then moved into the circular saw blade  16  with the linear stage  20  to achieve a straight cut.  FIG. 2  is a plan view of the tile cutting device  10  of  FIG. 1  set for a straight cut.  FIG. 4   a  is a plan view of the workpiece, tile  50 , with straight cut  60 . 
         [0017]    Arcuate cuts are performed by first fitting the power saw with a plunge type blade  18 . The power saw  14  is rotated on the saw bearing  40  to make the plunge type blade  18  perpendicular to the surface  28 ,  30  of the workpiece. The blade  18  is positioned in cooperation with the linear stage  20  to place the blade  18  in relation to the center  52  of rotation of the rotary stage  22  and the linear stage  20  locked. This permits cutting arcs of arbitrary radius. The workpiece is then positioned on the rotary stage and the plunge type blade is lowered by the arm lift/bearing  36  into the brittle material, cutting an arc as the workpiece is rotated under the blade  18  by rotating the rotary stage  22 . In like manner, freehand shapes may be cut in brittle materials with a plunge type blade  18  by moving both the rotary  22  and linear  20  stages simultaneously.  FIG. 3  is a plan view of the tile cutting device  10  of  FIG. 1  set for an arcuate cut.  FIG. 4   b  is a plan view of the tile  50  of  FIG. 4   a  with a curved cut  62 .