Stone working – Sawing – Rotary
Reexamination Certificate
2002-04-18
2004-05-18
Nguyen, Dung Van (Department: 3723)
Stone working
Sawing
Rotary
C125S014000
Reexamination Certificate
active
06736126
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to cutting saws, and more specifically to saws for cutting concrete.
When concrete is poured it is typically in a watery or flowing state which allows the concrete to be spread evenly over floors. After a period of time, varying with the mixture of the concrete, the temperature, and the moisture availability, the concrete attains a workable plasticity that permits the surface of the concrete to be formed and finished, typically, by troweling, rubbing, or brushing.
After the concrete is finished, it is allowed to stand for a period of time during which the concrete cures to obtain a rock-like hardness. As the concrete cures it undergoes thermal stresses causing the concrete to expand and contract in various manners depending on the shape and thickness of the concrete, and the type of concrete. These thermal stresses can cause cracking. The fully cured and hardened concrete also expands and contracts due to temperature changes with the result that cracks form in the concrete.
It is common practice to provide slots or grooves, commonly referred to as control joints, at predetermined intervals in the concrete. If the grooves extend all the way through the concrete, they can act as an expansion or contraction joint to help prevent cracking of the concrete. If the grooves are only on the surface of the concrete, then the grooves cause the cracks to form along the grooves so that they occur at regular intervals and are not visible. The grooves, but not the cracks, are visible.
One advantage to placing the grooves in the soft concrete is that a weakened plane is provided by the groove and that weakened plane is now installed before the concrete starts to cure and shrink. The concrete slab will typically seek out the weakened plane to crack in, if the plane is prematurely there. Although these grooves can be provided in the wet concrete just after it is poured by forming or grooving a slot with a grooving trowel, manually grooving the freshly poured concrete is impractical or very inconvenient and expensive for very large slabs of concrete.
For such large slabs, cutting saws have been provided for cutting finished concrete while it is in its “green” state before the concrete attains its rock like hardness and, preferably, before the concrete has shrunk sufficiently to cause cracking along planes other than those planes defined by the cut grooves. These conventional concrete saws commonly have a base plate on which are mounted two wheels and a skid plate, each of which contacts the concrete to provide a three point support on the concrete. A motor is pivotally mounted on the base plate and drives a circular saw blade that extends through a slot in the platform, and through a corresponding slot in the skid plate, in order to project into and cut the concrete below the skid plate.
The skid plate is a slotted metal sheet, typically made of steel, that skids along the surface of the concrete and acts as blade guide that applies a downward pressure as the cutting saw passes through the concrete, preferably with an upward cutting motion. During operation, however, the slotted area in the metal sheet, which widens due to wear, degrades the quality of the cut achieved by the cutting saw. When the quality of the cut made by the cutting saw is no longer acceptable, the skid plate is commonly discarded and replaced with a new skid plate.
Thus, the use of conventional skid plates leads to frequent repair of these component parts which is both costly from the standpoint of replacement parts, labor intensive maintenance, and lost production due to downtime. Moreover, the practice of using skid plates is wasteful in that they are disposed of once they are worn.
The foregoing illustrates limitations known to exist in present cutting saws. Thus it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, an alternative glide plate overlay and glide plate assembly for a cutting saw assembly are provided including the features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
A glide plate assembly is provided for a cutting saw having a cutting blade, including a glide plate bracket attachable to a cutting saw and having a substantially planar portion with a longitudinal aperture located therein. A glide plate overlay made of a material penetrable by the cutting blade is configured for attachment over the aperture in the glide plate bracket, such that upon attaching the glide plate bracket to the cutting saw with the glide plate overlay attached over the aperture and operating the cutting saw, a slot is formed in the glide plate overlay by the cutting blade. A glide plate overlay for attachment to the underside of a cutting saw having a cutting blade is also provided that includes a substantially planar portion disposed between two mounting portions, the mounting portions being configured to secure and position the glide plate overlay over a cutting slot located on the underside of the cutting saw.
A retrofit method is also provided for manufacturing a glide plate assembly for a cutting saw having a cutting blade. The retrofit method includes the steps of providing a skid plate of a concrete cutting saw, the skid plate having a planar portion with a longitudinal cutting slot dimensioned for a cutting blade. A glide plate overlay is provided and attached over the longitudinal cutting slot of the skid plate. The cutting saw is then operated so that a slot is formed in the glide plate overlay by the cutting blade.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with accompanying drawing figures.
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Michael G. Schroer (EarlyCut Diamond Products) letter to Leon Nigohosian, Jr. dated Jul. 2nd, 2002 in reference to Patent Application Titled “Glide Plate Overlay and Glide Plate Assembly for a Cutting Saw and Retrofit Method for Manufacturing Same”, 1 Page.
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Schroer Mark G.
Schroer Michael G.
Michael & Best & Friedrich LLP
Nguyen Dung Van
LandOfFree
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