Abstract:
A manual tile cutter includes a base adapted to support a tile, a rail connected to the base above the tile and a carriage slidably mounted on the rail. A manually operated lever and a cutting toolholder are independently pivotally mounted to the carriage at a common pivot point. A shaft has one end mechanically coupled to the cutting toolholder and an opposite end extending through the carriage and connected to a manually adjustable knob. A biasing element applies a force on the cutting toolholder toward the tile. A height adjusting device in mechanical communication with the knob and the cutting toolholder adjusts the height of the cutting tool with respect to the tile but independent of the lever to accommodate different tile thicknesses.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to tile cutters and more particularly, to an improved manual tile cutter for maintaining a constant cutting force. 
     With a conventional tile cutter, a cutting or scoring tool, for example, a carbide cutting wheel, is operatively connected to a carriage which slides along a guide bar. The base of the tile cutter has a longitudinally, generally centrally spaced breaker bar or edge on which the tile rests with the breaker bar being positioned beneath the desired tile break line. A manual lever arm is also connected to the carriage and is used to move the carriage and the cutting wheel across the tile surface along a path defining where the tile is to be cut and broken. The cutting wheel cuts a shallow groove or score line in the tile surface along the desired break line. Resilient pads normally support the tile on either side of the breaker bar. After the tile is scored, the lever arm is manipulated to place breaker jaws or plates against the surface of the tile on both sides of the scored line located directly over the breaker bar. As downward pressure is applied to the handle, the breaker plates apply downward forces on the top surface of the tile on both sides of the breaker bar. Continued application of the force is effective to cause the tile to break into two pieces, preferably at a location defined by the score line or groove. 
     For high quality tile cutting, it is necessary that a consistent score line be cut on each and every tile. Thus, it is important that the tile cutter have the capability of providing a constant force on the scoring wheel during the scoring operation. If the scoring groove is of an insufficient depth, that is, is less than other lines of weakness in the tile structure, the tile may fracture and break in directions other than along the scoring line. If the scoring force is excessive, the carbide cutting wheel may be damaged or broken; or the glazed finished surface may chip away from the scoring line; or the tile may be crushed. 
     It is also important that the scoring force be adjusted for different tile thicknesses. As the tile thickness increases, there is a higher probability that lines of weakness within the tile structure will intersect or run close to the score line. And, there is a greater probability that the tile will break along a line of weakness other than the score line. To minimize that probability, the cutting wheel scoring force should be greater to produce a deeper score line so that it is the weakest line of weakness in the tile body. Thus, the cutting wheel scoring force and depth of score line should increase as the tile thickness increases. 
     There are numerous known tile cutter structures providing some regulation of scoring force. However, such known designs are often either complex and expensive to manufacture or somewhat unreliable in not providing a consistent desired scoring force for different tile thicknesses over the useful life of the tile cutter. 
     SUMMARY OF THE INVENTION 
     The present invention provides a manual tile cutter of a simple and inexpensive construction that is easily adjusted to score tiles of different thicknesses and automatically provides the proper scoring wheel cutting force with each tile regardless of the tile thickness. 
     In accordance with the principles of the present invention and the described embodiments, the present invention is a manual tile cutter having a base adapted to support a tile. A rail is connected to the base above the tile and has a carriage slidably mounted thereon. A manually operated lever is pivotally mounted to the carriage at a pivot point, and a cutting toolholder having a rotatably mounted cutting tool is pivotally mounted to the carriage at the same pivot point. The lever and cutting toolholder are not connected together, and therefore, the cutting toolholder is free to pivot independent of a pivoting action of the lever. A shaft has one end mechanically coupled to the cutting toolholder and an opposite end extending through the carriage. A manually adjustable knob is connected to the opposite end of the shaft, and a biasing element applies a biasing force on the cutting toolholder toward the tile. A height adjusting device in mechanical communication with the knob and the cutting toolholder adjusts the height of the cutting tool with respect to the tile independent of the lever to accommodate different tile thicknesses. 
     These and other objects and advantages of the present invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating a preferred embodiment of the tile cutter in accordance with the principles of the present invention. 
     FIG. 2 is a longitudinal cross-sectional view of the carriage taken along line  3 — 3  of FIG. 1 in illustrating the height adjusting device in a first position. 
     FIG. 3 is a cross-sectional view of the carriage similar to FIG.  2  and illustrating the height adjusting device in a second position. 
     FIG. 4 is a cross-sectional end view taken along line  4 — 4  of FIG.  2  and illustrating the pivotal connection of the lever and cutting tool holder to the carriage. 
     FIG. 5 is a disassembled perspective view illustrating one embodiment of a tile height adjusting device in accordance with the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a tile cutter  10  is comprised of a generally rectangular base  12  which has a breaker bar, or breaker edge  14  extending centrally and longitudinally over the base  12 . The breaker bar  14  normally has a length equal at least to the length of the longest tile to be cut on the cutter  10 . The base  12  typically rests on a generally horizontal support surface. The breaker bar  14  projects a predetermined distance above the top surface  16  of the base  12 . On both sides of the breaker bar  14  and extending substantially over the entire upper surface  16  of the base  12  are pads  18 ,  20 , which help support a tile  22  to be cut. The pads  18 ,  20  may be made of any material that provides a resilient support for the tile  22  during the scoring and breaking process. 
     The tile cutter  10  further includes alignment blocks, for example, a fixed alignment block  24  and an adjustable alignment block  25 . End supports  30 ,  32  have a lower end rigidly connected at each end of the base  12  and extend in a generally perpendicular direction away from the top surface  16  of the base  12 . A pair of guide rails  34 ,  36  are connected to guide rail supports  38 ,  40  which are connected to the upper end of the end supports  30 ,  32 . The guide rails  34 ,  36  are mounted to be substantially parallel to the breaker bar  14  on the base  12 . A carriage  42  is slidably mounted on the guide rails  34 ,  36 . 
     Referring to FIG. 2, a manually operated lever  44  is pivotally connected to the carriage  42  at a pivot axis  46  which is below the elevation of the guide rails  34 ,  36 . One end of a tool holder  50  is pivotally mounted on the pivot axis  46  independent of the lever  44 . Thus, the lever  44  and tool holder  50  rotate independently of each other on pivot axis  46 . A cutting tool, for example, a carbide scoring wheel  48  is rotatably mounted to one end of a tool holder  50 . The height or elevation of the cutting wheel  48  with respect to the tile  22  is controlled by a height adjusting mechanism  52  including a manually rotatable knob  54 . As will be subsequently explained, rotating the knob  54  changes the elevation of an adjusting shaft or screw  56  which in turn moves the tool holder  50  and cutting wheel  48  to a different height as illustrated in FIG.  3 . 
     Referring to FIG. 5, the carriage  42  has shoulders  58 ,  60  which contain respective guide rail bores  62 ,  64 . Each of the guide rail bores  62 ,  64  are sized to receive respective bearings  66 ,  68  which in turn, slide on the respective rails  34 ,  36 . The carriage  42  further includes opposed identical projections  70 ,  72  which extend downward from the perspective shoulders  58 ,  60  toward the base  12 . The pivot axis  46  is implemented using a pivot pin or shaft  80  that extends between and is secured to the projections  70 ,  72  of the carriage  42 . The lever  44  has a forked end with opposed legs  74 ,  76  with respective bores  77 ,  78  that are sized to rotatably receive the pivot pin  80 . The tool holder  50  has opposed shoulders  82 ,  84  which fit between the respective legs  74 ,  76  of the lever  44 . The pivot pin  80  is rotatably received within the bores  86 ,  88  in the respective shoulders  82 ,  84  of the tool holder  50 . Thus, the lever  44  and the tool holder  50  pivot freely and independently on the pivot pin  80 . An opposite end of the tool holder  50  has a forked end  90 . The scoring wheel  48  is rotatably mounted on an axle  92  (FIG.  2 ), and the ends of the axle  92  are securely mounted in the legs  94 ,  96  of the tool holder forked end  90  (FIG.  4 ). Thus, the scoring wheel  48  rotates freely with respect to the tool holder  50 . 
     The height adjusting screw  56  has a lower end that extends between the shoulders  82 ,  84  of the tool holder  50  and is connected to an axle  100  that is rotatably mounted within bores  102 ,  104  (FIGS. 2 and 3) of the respective shoulders  82 ,  84  of the tool holder  50 . Referring to FIG. 2, the lower end  103  of the adjusting screw  56  is threaded into the axle  100 . The upper end of the adjusting screw  56  extends through a hole  106  in the top  108  of the carriage  42  and then through a hole  110  in the bottom of the knob  54 . The upper end of the screw  56  has an enlarged head portion  112  located within a cavity  114  of the knob  54 . The screw  56  passes through a centering washer  116  in the cavity  114  to properly locate the screw  56  with respect to the knob  54 . A second centering washer  118  locates the adjusting screw  56  with respect to the carriage  42 . The centering washer  118  further provides an upper bearing surface for a biasing element, for example, a compression spring,  120 . A lower bearing surface is provided by a washer  122 . The cavity  114  within the knob  54  is covered by a cap  124 . 
     The threaded engagement of the screw  56  into the axle  100  provides two functions. First, rotating the screw  56  raises and lowers the tool holder  50  and cutting wheel  48  with respect to the carriage  42  and the tile  22 . Normally when the cutting wheel  48  is not engaged with the tile as shown in phantom in FIG. 2, the tool holder  50  should be at a height such that as the carriage is moved to the left as illustrated in FIG. 2, the cutting wheel  48  and not the tool holder  50 , engages the edge  126  of the tile. Thus, with continued motion of the carriage  42 , as the cutting wheel  48  engages the edge  126 , it easily rides up onto the upper surface  128  of the tile  22 . Adjusting the screw  56  also adjusts the biasing or scoring force applied by the spring  120  on the cutting wheel  48 , that is, a force resisting motion of the cutting wheel  48  in the upward direction. 
     As shown in FIG. 2, a tile of a first thickness, for example, 0.250 inches, can be scored and broken. Referring to FIGS. 3 and 5, a tile  129  of greater thickness, for example, 0.375 inches, may be scored and broken. To accommodate the thicker tile  129 , the tile cutter  10  includes a tile thickness adjusting mechanism  52  comprising a fixed cam  130  mounted on the top  108  of the carriage  42  and a movable cam follower  132  mounted within the knob  54 . The fixed cam  130  has an undulating annular cam surface  134  with two diametrically opposed upper positions defined by detents  136  and two diametrically opposed lower positions  38 . The upper positions  136  are angularly separated from the lower positions  138  by approximately 90°. With the knob in the position illustrated in FIG. 2, the cam follower  132  is located at a lower position  138  on the surface  134 . By rotating the knob  54  90° to the position shown in phantom in FIGS. 3 and 5, the cam follower  132  is moved to the upper position detent  136  on the surface  134 . The vertical distance or elevation between the bottom of the detent  136  and lower position  138  on the cam surface  134  corresponds to the difference in thickness between the tiles  22 ,  129 . 
     As the cam follower  132  moves from the lower position  138  along the surface  134  toward the upper position  136 , the knob  54  is lifted vertically upward with respect to the breaker bar  14  on the base  12 . As the knob  54  elevates, the screw  56  also elevates, thereby lifting the tool holder  50  and the cutting wheel  48 . When the cam follower  132  engages the upper position detent  136 , the rotation of the knob  54  is stopped; and the cutting tool  48  is at an elevated position as illustrated in FIG.  3 . As the cutting wheel  48  and tool holder  50  elevate, the compression spring  120  is compressed, thereby applying a greater biasing or scoring force on the cutting wheel  48 . The greater scoring force will provide a deeper scoring groove to facilitate cutting the thicker tile  129 . 
     In use, the lever  44  and carriage  42  are pulled toward the end  32  of the base  12 . A tile is then placed against the alignment block  24  with the desired score line or break line aligned with the breaker bar  14 . The knob  54  is rotated to provide a height of the cutting wheel  48  to match the thickness of the tile being cut. By pushing the handle  44  horizontally but not downward, the carriage  42  is moved along the rails  34 ,  36  toward the end  30  of the base  12 . The scoring wheel  48  initially engages the edge  126  of the tile and rides up onto the upper surface  128  of the tile. The spring  120  provides a downward scoring force on the cutting wheel  48  such that, as the cutting wheel  48  moves across the tile, a scoring groove of the desired depth is cut. A continued pushing on the handle  44  causes the scoring wheel  48  to move completely across the tile and drop into a pocket  134  of the alignment bar  24 . The handle  44  is then lowered so that the breaker plates  156  contact the tile on either side of the breaker bar  14 . Continued downward pressure on the lever arm  44  will cause the tile to break over the breaker bar  14  along the score line. 
     While the invention has been illustrated by the description of one embodiment and while the embodiment has been described in considerable detail, there is no intention to restrict nor in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those who are skilled in the art. For example, while the adjustment screw  56  is disclosed as threadedly engaging the axle  100 , which is rotatably mounted within the tool bar  50 . As will be appreciated, if the springs  120  on different tile cutters have relatively consistent spring constants, the adjusting screw  56  will be adjusted to have the same length between its head  112  and the tool holder  50 . Therefore, alternatively, the adjusting screw  56  can be nonthreadedly fixed into the tool holder  50  to provide the desired length. Further, as will be appreciated, instead of the axle  100  being rotatably mounted in the tool holder, alternatively, the axle can be fixed within the tool holder  50  or eliminated altogether and the lower end of the shaft  56  fixed by welding, adhesives or other connecting agents at its correct length between the shoulders  82 ,  84  of the tool holder  50 . 
     The spring  120  may be any type of device that provides the desired biasing force, that is, a resistance to the cutting wheel  48  moving in the upward direction. Therefore, the spring  120  could be replaced by one or more Belleville washers, a leaf spring, a bushing made from rubber or other elastic material, etc. Further, the height adjusting mechanism  54  is described as having two height adjustments which are separated by a 90° rotation of the knob  54 . As will be appreciated, other cam detents can be provided in the cam surface  134  so that the cutting wheel  48  can be adjusted to three or more heights. Alternatively, the cam  130  and cam follower  132  may be eliminated; and instead, the knob  54  fixed to the adjusting screw  56 . Thus, by rotating knob  54  and adjusting screw  56 , the cutting wheel  48  is raised and lowered to different heights to accommodate different tile thicknesses. With that embodiment, the height of the cutting wheel  48  is infinitely adjustable. 
     Therefore, the invention in its broadest aspects is not limited to the specific details shown and described. Consequently, departures may be made from the details described herein without departing from the spirit and scope of the claims which follow.