This invention involves an improved method and apparatus for maintaining a cutting blade aligned with a previously cut groove and is typically used to more uniformly and precisely shape the edges of grooves previously cut in concrete surfaces.
Concrete surfaces are commonly used for roads, driveways, sidewalks, flooring and to form other flat surfaces. As the concrete cures a chemical reaction occurs and the concrete shrinks and cracks. Grooves are cut in the concrete to form weakened planes and to cause the cracks to form along the grooves rather than randomly cracking. These crack control grooves were typically cut the day after the concrete was poured and finished, and cut from ¼ to ⅓ the thickness of the concrete slab being cut. More recently the grooves are often cut shortly after the concrete surface is finished using processes and equipment described in patents to Chiuminatta, et al., and the depth of the groove is less than ¼ the thickness of the concrete being cut, and sometimes as shallow as half an inch. In addition to these crack control grooves, grooves are sometimes cut or formed for decorative purposes. The depth of these decorative cut grooves will vary.
But whether cut early or the next-day after finishing, these cut grooves have a sharp corner on each edge of the groove. These sharp corners tend to break over time and that is not attractive. For aesthetic and structural reasons, there are advantages to rounding or altering the otherwise sharp corners on these grooves which are cut in the concrete surface. This is currently done by grinding or cutting the corners to the desired shape with a blade at least partially coated with abrasives and which is configured to form the desired shape on the edges of the groove. The more common shapes for the exterior edges of the groove are V-shaped notches which put a flat bevel on opposing edges of the groove, or rounded edges on the groove.
Unfortunately, as the abrasive blade cuts or forms the corners of the groove, the blade moves up and down as the concrete surface varies or as the operator moves the saw driving the blade. Further, the abrasive blade is guided along the pre-cut groove by the operator, and that results in the blade weaving back and forth along the groove. The weaving occurs even though a guide may be placed on the saw which follows or extends into the groove in the front of the abrasive blade. Each movement of the blade relative to the concrete surface or away from the centerline of the pre-cut groove causes the shaped edges to vary and that is undesirable. There is thus a need for a better way to cut or form the edges of these pre-cut grooves in a more consistent manner.