Severing by tearing or breaking – Breaking or tearing apparatus – Combined with preliminary weakener or with nonbreaking cutter
Reexamination Certificate
1999-05-12
2001-08-07
Rachuba, M. (Department: 3724)
Severing by tearing or breaking
Breaking or tearing apparatus
Combined with preliminary weakener or with nonbreaking cutter
C225S096000, C125S023020, C083S886000
Reexamination Certificate
active
06269994
ABSTRACT:
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.
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North American Tile Tool Company
Rachuba M.
Tran Kim Ngoc
Wood Herron & Evans L.L.P.
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