Woodworking – Special-work machine – Stump removing
Reexamination Certificate
2002-05-07
2004-03-23
Bray, W. Donald (Department: 3725)
Woodworking
Special-work machine
Stump removing
C144S235000, C144S241000, C144S334000, C299S102000
Reexamination Certificate
active
06708743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for use in grinding a tree stump. More particularly, the invention relates to a stump grinding assembly that includes a cutting tooth and a holding block for the cutting tooth.
2. Description of Related Art
It is sometimes desirable to remove a tree stump. Rotary wheel stump grinders are typically employed for this purpose. Conventional rotary stump grinding wheels typically employ a plurality of cutting teeth that extend from the rotary wheel. During normal operation of the stump grinder, the cutting teeth are subjected to large impact and abrading forces. Consequently, the teeth and the wheel may break due to the impact and wear out due to the abrading force. When this occurs, one or more teeth must be replaced. Replacement of stump grinding teeth can be a time consuming process, in part because the radial projection of each tooth must be adjusted to a predetermined, optimum value before fastening the tooth to the wheel.
In some prior art stump grinding devices, cutting teeth are directly fastened to the rotary wheel. If the tooth is fastened to the wheel using a bolt, for example, then the bolt is solely responsible for holding the tooth to the wheel. If the impact force applied to the tooth is larger than the bolt's shear strength the bolt will fail and the tooth will shear away from the wheel. In such arrangements, the wheel can also be damaged when a large impact force is applied to one or more teeth. The impact force on the tooth is communicated directly to inner surfaces of the wheel that define the bolt hole(s) that receive the bolt(s). The impact force may cause the aperture through which the bolt passes to misshape or enlarge. Consequently, the fit of a replacement bolt may become loose and subject the tooth and wheel to additional damage.
Mounting the tooth to a block on the periphery of the wheel does not provide a suitably thick section on which to fasten the tooth. Because there is no thick wheel portion to support the block, and further to support the tooth, there is an increased likelihood that the tooth and block may be sheared from the wheel.
With reference to teeth that fasten directly to the wheel, a proper seat of the tooth against the wheel is desirable. Teeth that are formed from cast metal sometimes have protuberances and bumps that, although small, preclude a flat surface-to-surface contact between the tooth and the wheel. That is, the bumps act as legs between a surface on the tooth and the surface of the wheel. This can allow play between the tooth and the wheel and can exacerbate the effect that the impact force has on the tooth. Also, moisture can wick under the tooth to create rust and corrosion. Rust and corrosion of the teeth has been a reoccurring problem in the use of these types of teeth and wheel assemblies.
SUMMARY OF THE INVENTION
The present invention provides a stump-grinding apparatus for use with a stump-grinding wheel. The apparatus includes a block having an inner surface and an outer surface. The inner surface is adjacent to a side of the wheel between the center of wheel and the peripheral edge. The outer surface defines both a groove and a first aperture in the groove. A tooth is received into the groove. The tooth has a first end and a second end spaced from the first end. The second end defines a second aperture that can align with the first aperture. A fastener extends through the first and second aperture to fasten the tooth to the block.
The present invention also provides a stump-grinding apparatus. The stump-grinding apparatus includes a stump-grinding wheel that is centered on an axis and has a peripheral edge. The stump-grinding apparatus also includes a first cutting assembly that secures to the wheel. The first cutting assembly includes a first tooth that extends beyond the peripheral edge of the wheel. A second cutting assembly, which is also secured to the wheel, includes a second tooth that extends from the side of the wheel at an angle in the range of about 35 to about 55 degrees relative to a plane defined by the side of the wheel.
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Webpages from www.vermeer.com, viewed on Mar. 23, 2002.
Copy of Vermeer Full-Line Catalog, 2001.
Webpages from www.raycomfg.com, viewed on Mar. 4, 2002.
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Bray W. Donald
Bucktooth Grinding Company LLC
Rankin, Hill Porter & Clark LLP
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