Cutlery – Cutting tools – Saw
Reexamination Certificate
2002-03-06
2004-01-20
Payer, Hwei-Siu (Department: 3724)
Cutlery
Cutting tools
Saw
C030S296100, C030S373000, C030S388000
Reexamination Certificate
active
06678960
ABSTRACT:
FIELD OF THE INVENTION
This invention relates in general to undercut saws, and more specifically involves an undercut saw with a centrally located height adjustment mechanism.
BACKGROUND OF THE INVENTION
Undercut saws or flush-cutting saws are used to undercut doors and baseboards, typically by about 0.25 inches to 1.75 inches, to provide sufficient space for floor coverings to fit underneath.
Conventional undercut saws use a cutting assembly including an electric rotary motor driving a shaft rotating a flat, circular cutting blade in a horizontal plane. The cutting assembly is held above a guide surface, such as a floor, by a base that provides a large stable skid surface for sliding the saw along the floor. The base includes an inner portion attached to the cutting assembly, horizontal portion extending radially outward therefrom and past the blade circumference, and an outer generally vertical leg portion extending down from the periphery of the horizontal portion to rest on the floor.
The blade is adjusted vertically by adjusting the height of the leg of the base. Typically, the leg comprises includes inner and outer mating vertically telescopic collars. The relative position of the collars is determined in a manner such as the inner collar having a plurality of spaced protruding studs, the outer collar having slots for receiving the studs, and a plurality of wing nuts, each attached to a stud for clamping the collars together.
This peripheral adjustment approach has several shortcomings. Notably, it is slow because several fasteners require adjustment. More importantly, using the peripheral adjustments, it is difficult to adjust the height so that the blade is level. The blade is only level if each of the peripheral studs and wing nuts, are at the same height. This is not quickly and easily accomplished.
It is desirable that an undercut saw include a vacuum attachment to capture cuttings. Another shortcoming of peripheral height adjustment is that a vacuum cannot be attached to the periphery of the blade shroud because the vertical portion of the shroud must adjust.
At least one attempt has been made to provide central height adjustment using an angled drive, but this resulted in an awkward, unbalanced device requiring a large triangular base.
Therefore, there has been a need for an undercut saw with improved mechanism that quickly and accurately adjusts the cutting height while maintaining the blade level and that does not otherwise detract from the ergonomics of the saw.
SUMMARY OF THE INVENTION
This invention is an undercut saw having a central axis, generally comprising a cutting assembly and a base. The cutting assembly comprises a case that houses an electric motor that drives a shaft upon which a saw blade is mounted to rotate in a plane perpendicular to the central axis. The base supports the cutting assembly above a support surface and comprises a cylindrical sleeve horizontally surrounding the motor case and supporting the case such that the central axis is vertical, and a blade shroud extending radially outward to define a blade cavity covering the majority of the blade except for a cutting area. The cutting assembly and base include cooperative height adjustment means for selectively moving the case vertically within the base so as to adjust the height of said blade relative to the support surface.
A passageway connected to the blade cavity is adapted for attachment to a vacuum device for vacuuming blade cuttings from the blade cavity.
A blade guard assembly is rotatable between a retracted position adjacent said shroud and an extended position covering the cutting area of the blade so as to include the cutting area in the blade cavity.
A wall guide is selectively positionable to align the blade with a workpiece and limit the depth of blade cut.
Other features and many attendant advantages of the invention will become more apparent upon a reading of the following detailed description together with the drawings wherein like reference numerals refer to like parts throughout.
REFERENCES:
patent: 2610658 (1952-09-01), Koeling
patent: 4993243 (1991-02-01), Guinn
patent: 5088865 (1992-02-01), Beth et al.
patent: 5327649 (1994-07-01), Skinner
patent: 5784789 (1998-07-01), Vargas
patent: 5853274 (1998-12-01), Coffey et al.
patent: 5974674 (1999-11-01), Kelly
Payer Hwei-Siu
Tervo Calif
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