The present invention relates generally to material processors and to methods of processing material, such as asphalt shingles.
It is well known in the art that adding a mixture of 4-10% recycled asphalt shingle by-product to road pavement enhances the pavement's stability, reduces cracking of the pavement, and increases the pavement's durability. Therefore, a demand exists for such by-products of recycled asphalt shingles and it is desirable to efficiently and economically grind asphalt shingles into byproduct for use in road pavement.
It has been previously known in the art to use wood-grinding apparatus to grind asphalt shingles. A wood grinding apparatus generally employs a large rotating drum with grinding heads attached to the outside of the drum. The drum is located inside an outer container having a screened portion. The screened portion allows wood chips to exit through the screen once they are small enough.
The wood grinding heads comprise a body for attachment to the outside of the rotating drum and a grinding tool that attaches to the body. As the drum rotates, the grinding heads also rotate and wood material is fed into the screened container and toward the rotating drum. As the material contacts the rotating grinding heads, the material is ground into by-product. This by-product continues to cycle around the inside of the screened container and be ground until the by-product's diameter is small enough to exit through the screened portion.
These wood-grinding apparatus work well grinding wood, but when grinding asphalt shingles they create excessive frictional heat that melts the shingles, thereby hindering the grinding and causing significant damage to the apparatus, as explained below.
A popular wood-grinding head used to process asphalt shingles is shown in
The excessive heat is produced because the grinding apparatus inefficiently processes the extremely abrasive asphalt shingles. Most of the frictional heat is created when the raker of each head rubs against the shingles. Also, as the shingles must reach approximately one inch in diameter, they cycle around the inside of the screened container, thereby creating more friction. The shingles are cut and raked repeatedly until they are small enough to exit through the screen, thereby creating the excessive frictional heat that melts the shingles.
When the shingles melt inside the processing apparatus, the apparatus becomes bound and damages the drum-driving motor and the cutting heads. Also, the apparatus will not function again until the melted asphalt is removed, which is costly and time consuming. The available wood-grinders are too inefficient and create too much friction, thereby creating high temperatures that melt the asphalt shingles before the desired byproduct is produced.
The above noted problems are clearly evidenced by the fact that it was only commercially viable to use that apparatus to grind asphalt shingles in an extremely cold environment, such as the far northern hemisphere during winter, where extremely low temperatures prevented the shingles from melting during grinding. Thus, it would be desirable to develop a cutting apparatus and method for cutting asphalt shingles that produces the desired product while avoiding the inconveniences caused by melted shingles.
The present invention fills the aforementioned needs by providing a method and apparatus for efficiently cutting asphalt shingles, thereby efficiently producing the desired product without melting the asphalt shingles.
One embodiment of the present invention defines a cutting head adapted to be mounted on a rotating member for travel in a forward direction, comprising a base having a leading area and a trailing area, a cutting tool having a body attached to the front area, and first and second cutting teeth mounted to the body and extending substantially parallel to one another. An opening is disposed between the first and a second cutting teeth, the first and second cutting teeth defining a first and second cutting path, respectively. A rear cutter member is attached to a trailing area for travel in a third cutting path between the first and the second cutting path. The first and second cutting teeth include respective funneling surfaces that are angled inwardly toward the opening in a trailing direction for directing material cut by the teeth through the opening and into the third cutting path.
Many advantages of the present invention will be apparent to those skilled in the art with a reading of the specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein:
In the present invention, the prior art's raker has been replaced by a tool configured to cut the material being processed, and to funnel the cuttings into the path of a rear cutting tool trailing between and behind the teeth. Materials, such as asphalt shingles, can now be cut with less friction, thus minimizing any melting of the shingles.
A wear bit 35 is mounted to the body 10 adjacent to the opening 34 and between the teeth 30. The bit 35 is preferably made from carbide and is brazed to the body 10, but can be made from other suitable materials. As the cutting tool 1 cuts shingles, this bit 35 contacts the shingles and gradually wears away thereby preventing the body 10 from wearing through to the hole 20 and compromising the attachment to the base 5. Preferably, the bit 35 will last long enough so that once it is worn away, the cutting teeth are also worn, thereby requiring replacement of the cutting tool. Now make reference to
The cutting action produced by the tool according to the present invention is unique and capable of cutting asphalt shingles more quickly, thereby generating less frictional heat that would otherwise tend to melt the shingles. Therefore, use of the invention avoids problems created in the prior art when asphalt shingles melt during cutting.
The above are exemplary modes of carrying out the invention and are not intended to be limiting. It will be apparent to those of ordinary skill in the art that modifications thereto can be made without departure from the spirit and scope of the invention as set forth in the accompanying claims.