Mining or in situ disintegration of hard material – Cutter tooth or tooth head – Rolling or rotatable bit
Reexamination Certificate
1999-03-22
2001-03-06
Bagnell, David (Department: 3673)
Mining or in situ disintegration of hard material
Cutter tooth or tooth head
Rolling or rotatable bit
C299S110000, C299S104000, C299S113000
Reexamination Certificate
active
06196636
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a cutting tool, and more particularly to a cutting bit insert and ring of the type for fixing to a rotable shank where the bit insert is a polygonal pyramid and the bit insert is harder than the ring.
2. Description of the Related Art
Various types of configurations have been used in the past for the bits of abrading or cutting instruments. It is conventional in the art to attach a cutting bit insert made of a blended material, which includes some tungsten carbide, to one end of a shank and to then insert the shank into a block. The block is then pushed along a surface, the force of the surface on the cutting bit insert causing rotation of the bit insert and shank and abrasion or cutting of the surface. The use of this general configuration is old in the art.
Many of the modifications of this general configuration have been made to the cutting bit insert and to the geometry of the juncture between the bit insert and the shank. Examples of these types of modifications can be found in the patents to Den Besten et al., U.S. Pat. No. 4,201,421; Ojanen, U.S. Pat. Nos. 4,497,520 and 4,547,020; Penkunas et al., U.S. Pat. No. 4,725,099; Mills, U.S. Pat. Nos. 4,823,454 and 4,932,723; Stiffler et al., U.S. Pat. Nos. 4,911,503 and 4,940,288; Larsson et al., U.S. Pat. Nos. 4,938,538 and 5,161,859; and Stiffler, U.S. Pat. No. 4,941,711.
Other modifications have been made to the cutting bit insert itself by including radially extending ribs along a portion of the cutting bit insert. Examples of this type of modification can be found in the patents to Maddock, U.S. Pat. No. 3,361,481; Radd, U.S. Pat. No. 3,746,396; Rowlett et al., U.S. Pat. No. 5,131,725; Massa et al., U.S. Pat. No. 5,324,098; and Sollami, U.S. Pat. Nos. 5,484,191 and 5,551,760.
Other modifications have been made to the shank, the block, or the joints between the cutting bit insert and the shank or the shank and the block. These modifications have been designed to increase the durability of the various parts and keep them from deteriorating over time from abrasive contact with the asphalt. Examples of structures which attempt to increase durability are shown in the patents to Dziak, U.S. Pat. No. 4,489,986; Beebe, U.S. Pat. No. 4,561,698; Mills, U.S. Pat. No. 4,660,890; Beach, U.S. Pat. No. 4,725,098, and Graham et al., U.S. Pat. No. 5,417,475.
However, even though there have been numerous designs created and previously used, it is desirable that an improved configuration be used which further increases the abrasion properties of the bit while decreasing the erosion of the remainder of the structure. The present invention is an improvement in this area and includes these and other important features.
SUMMARY OF THE INVENTION
The present invention relates to the configuration of a cutting tool. The cutting tool includes a shank, a cutting bit insert, and a protective ring. The cutting bit insert and the ring are of the type for fixing to the rotatable shank.
The cutting bit insert has a plurality of integrally formed portions. The portions are configured in a polygonal pyramid shape, and there are preferably first, second, and third portions. The polygonal pyramid is provided with a selected number of faces and is preferably octagonal. Adjacent ones of the faces of the pyramid meet at common edges. These common edges intersect at a vertex which forms one end of the cutting bit insert. The faces of the first portion slope away from the vertex at a first angle relative to a longitudinal axis of the cutting bit. The faces of the second portion slope away from the first portion at a second angle relative to the longitudinal axis. In a preferred embodiment, the faces of the third portion slope away from the second portion at a third angle relative to the longitudinal axis.
The cutting bit insert also includes a flange which extends outwardly from the faces of one of the portions, preferably the third portion. A protective ring is mounted in surrounding relationship to the flange. The bit insert has a first hardness and the ring has a second hardness lower than the first hardness.
REFERENCES:
patent: 3356418 (1967-12-01), Healey et al.
patent: 3361481 (1968-01-01), Maddock
patent: 3746396 (1973-07-01), Radd
patent: 3833264 (1974-09-01), Elders
patent: 4201421 (1980-05-01), Den Besten et al.
patent: 4489986 (1984-12-01), Dziak
patent: 4497520 (1985-02-01), Ojanen
patent: 4547020 (1985-10-01), Ojanen
patent: 4561698 (1985-12-01), Beebe
patent: 4660890 (1987-04-01), Mills
patent: 4725098 (1988-02-01), Beach
patent: 4725099 (1988-02-01), Penkunas et al.
patent: 4823454 (1989-04-01), Mills
patent: 4911503 (1990-03-01), Stiffler et al.
patent: 4932723 (1990-06-01), Mills
patent: 4938538 (1990-07-01), Larsson et al.
patent: 4940288 (1990-07-01), Stiffler et al.
patent: 4941711 (1990-07-01), Stiffler
patent: 5131725 (1992-07-01), Rowlett et al.
patent: 5161859 (1992-11-01), Larsson et al.
patent: 5219209 (1993-06-01), Prizzi et al.
patent: 5324098 (1994-06-01), Massa et al.
patent: 5417475 (1995-05-01), Graham et al.
patent: 5484191 (1996-01-01), Sollami
patent: 5551760 (1996-09-01), Sollami
patent: 5823632 (1998-10-01), Burkett
patent: 6019434 (2000-02-01), Emmerich
patent: 870701 (1981-10-01), None
McSweeney Larry J.
McSweeney Lawrence H.
Mills Ronald D.
Bagnell David
Foster James H.
Kremblas, Foster, Millard & Pollick
McSweeney Larry J.
Singh Sunil
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