Cutlery – Cutting tools – Saw
Reexamination Certificate
2002-02-15
2004-01-13
Watts, Douglas D. (Department: 3724)
Cutlery
Cutting tools
Saw
Reexamination Certificate
active
06675486
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of bandsaws. More specifically, the present invention discloses a portable bandsaw that is balanced so that its center of gravity coincides with the cutting edge of the bandsaw blade.
2. Statement of the Problem
Bandsaws have been used for many years to cut wood, metal, plastics and other materials. A conventional bandsaw has a blade forming an endless loop that extends about two or more transport wheels. One of the wheels is driven by an electric motor to drive the bandsaw blade. The work piece is typically fed on a platen extending outward from the bandsaw blade so that the work piece will intersect the moving blade at a desired location and orientation. Conventional bandsaws are typically large, floor-mounted fixtures, which limits their mobility and also limits their ability to handle very large work pieces due to space constraints in most factories and workshops. In addition, when dealing with very large work pieces (e.g., logs or large timbers), it is much easier to move the saw relative to the work piece, rather than manipulating the work piece relative to the saw.
Therefore, a need exists for a portable bandsaw that can be readily transported for use at remote work sites or used to cut large work pieces. In addition, since there is no longer a large base for supporting the bandsaw, a portable bandsaw must have good handling and safety characteristics. In particular, a portable bandsaw should be carefully balanced so that its center of gravity coincides with the cutting edge of the blade to minimize the forces needed to control and manipulate the saw.
3. Prior Art
The prior art in this field includes a variety of bandsaws that enable the blade to pivot or tilt relative to the work piece, including the following:
Inventor
U.S. Pat. No.
Issue Date
Crane
2,774,131
Dec. 18, 1956
Hack
3,084,723
Apr. 9, 1963
Majus
3,952,622
Apr. 27, 1976
Aoyagi
5,107,738
Apr. 28, 1992
Hansen
5,178,052
Jan. 12, 1993
Moller et al.
5,193,518
Mar. 16, 1993
D'Arcy
5,341,712
Aug. 30, 1994
Jasinski
5,878,644
Mar. 9, 1999
These references show a wide variety of bandsaws with blades that rotate, tilt, or pivot. For example, the bandsaws disclosed in the D'Arcy, Hack, and Jasinski patents have blades that tilt or pivot with respect to the bandsaw frame or the work piece.
Crane discloses a bandsaw with a manually-controllable power-drive feed for the work piece.
Majus discloses a vise-mounted bandsaw that enables the bandsaw blade to cut from the wide range of possible orientations.
Aoyagi discloses a bandsaw that is capable of cutting a work piece along two different directions.
Hansen discloses a bandsaw for cutting items of elastic material, such as foam rubber, in which the cutting mechanism is supported by rocker arms.
Moller et al. disclose a portable wire saw. Wheels attached to the base provide a pivot point so that the wire saw can be pivoted between a cutting position and a non-cutting position.
In addition to these patents, two portables bandsaws have been available on the market for several years. The portable bandsaw marketed under the MAFFELL trademark has two transport wheels with a motor driving the lower transport wheel. The portable bandsaw marketed under the OLIVER trademark has two transport wheels with a motor driving the upper transport wheel. In both cases, most of the weight is on one side of the blade due largely to the position and weight of the motor. This results in a bandsaw that is lopsided, ungainly, and relatively difficult to manipulate.
4. Solution to the Problem
None of the prior art references discussed above show a portable bandsaw having a center of gravity that coincides with the cutting edge of the bandsaw blade. The present invention provides a lightweight three-wheeled bandsaw in which the electric motor is positioned to serve as a counterweight to the frame and the other components of the bandsaw. This configuration results in a portable bandsaw that is well balanced, turns in either direction with little effort, and offers precise control in cutting along a desired path.
SUMMARY OF THE INVENTION
This invention provides a portable bandsaw having a bandsaw blade extending around a plurality of transport wheels driven by a motor. The frame of the bandsaw supports these components such that the center of gravity of the bandsaw coincides with the cutting edge of the bandsaw.
REFERENCES:
patent: 2774131 (1956-12-01), Crane
patent: 3084723 (1963-04-01), Hack
patent: 3952622 (1976-04-01), Majus
patent: 4160320 (1979-07-01), Wikoff
patent: 4212104 (1980-07-01), Wikoff
patent: 4242798 (1981-01-01), Wikoff
patent: 5018492 (1991-05-01), Wolf et al.
patent: 5107738 (1992-04-01), Aoyagi
patent: 5178052 (1993-01-01), Hansen
patent: 5193518 (1993-03-01), Moller et al.
patent: 5251525 (1993-10-01), Galloway
patent: 5341712 (1994-08-01), D'Arcy
patent: 5878644 (1999-03-01), Jasinski
patent: 5992025 (1999-11-01), Fricke
Dorr, Carson, Sloan, Birney & Kramer, P.C.
Watts Douglas D.
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