Geometrical instruments – Gauge – Collocating
Reexamination Certificate
2002-05-29
2004-04-27
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
Collocating
C033S042000, C033S471000, C033S464000
Reexamination Certificate
active
06725558
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
This invention relates generally to tool guides, and more particularly to an adjustable tool guide that provides accurate set up and guide placement to reduce the time necessary to perform cutting or milling operations by a variety of hand-held power tools.
In woodworking, there are a variety of guides that provide a secure surface on which the edge of a hand-held power tool can slide as it is moved through a cutting or milling operation. These guides can be used to trim large panels or other sheet material. For example, doors are typically manufactured over-sized and trimmed to fit a given door opening in a wall. Carpenters spend considerable time measuring the size and squareness of the opening and then trimming the door to match.
Cutting the door with a circular saw is common practice, and skilled carpenters can cut to a pencil or scribe line marked on the door. Yet even skilled carpenters do not make flawless cuts, and circular saws can cause chipping and splintering of the door. Further, running the platen of the circular saw across a door can cause scratches or other blemishes that must be repaired.
Tool guides can be used to ensure the cut is straight. For example, a product known as Clamp-N-Guide is an aluminum extrusion that incorporates a clamping mechanism to secure it to a flat surface such as a panel or a door. The edge is straight, so a carpenter sets the guide at a distance from the desired cut location so that the spacing from the guide to the cut line equals the spacing from the tool's edge to the saw blade or router bit. Once set, the tool can be operated along the guide's edge to cut a line at the desired location. One of this device's shortcomings is that the guide must be placed at an exact distance from the cut line and that distance varies from tool to tool. Thus, a carpenter must measure the tool and set both ends of the guide at the appropriate distance. This requires careful set up and possibly some trial and error testing to ensure accuracy. Further, using an edge guide of this type provides no protection against splintering of the wood or marring of the surface from the tool's base plate.
This regimen of set-up, testing, and cutting must be completed every time a separate cut is made. On cuts that are uniformly 90° square with adjacent edges it is time-consuming and, if performed inaccurately, leaves a very obviously flawed cut.
Cuts that are greater or less than 90° to adjacent edges require an even greater amount of set up time because different guide-to-cutting edge calculations must be made for each end of the guide.
There are so-called compass guides that can be adjusted to guide a tool at a variety of angles relative to the edge of a board. These guides are short and can only be used to cut framing lumber. Further, these guides still require the carpenter to calculate the distance from the guide edge to the tool's cutting edge for accurate guide placement. Further, a compass guide provides little protection against marring of a surface by the tool as it is pushed along the guide.
One prior art tool guide that has been used, but not mass-marketed, includes a flat base panel, an edge bar, and a tool rail. The panel is first cut by its associated power tool by passing the tool along the tool rail to define a base panel edge that corresponds exactly to the distance from the tool rail to the cutting edge of the tool. This permits the guide to be placed with its cut edge on the exact line of the intended cut. The base plate also protects the piece to be cut from being marred by the sliding tool base.
As a further advantage of this type of tool guide, the edge bar can be placed against an adjacent edge of the piece to be cut. With the cut edge of the base plate set on a single point of the intended cut line, the tool guide will control the tool to cut a line that is at a right angle to the edge bar. In this manner, doors or panels can be cut square with minimal set up or measurement.
This type of tool guide is essentially limited to making right angle cuts. It is also necessary to have a different tool guide for each tool that may be used to make a cut because its base plate's cut edge is unique to match the spacing of the tool rail and cutter for that particular tool. If different tools are used or different cutters (such as different diameter router bits) on the same tool, the cut edge of the base plate will not define a true cut line. This requires calculating the appropriate spacing from the guide to the cut line or a new guide must be used. Either way, the value of such a guide is diminished when a variety of tools are used with it.
Thus, there is a need for a tool guide that can be used with a variety of different tools and cutter sizes to minimize set up and calculations, and give accurate cuts at a variety of angles relative to adjacent edges.
SUMMARY OF THE INVENTION
A tool guide in accordance with the present invention requires little effort to set up and use. It provides accurate guidance for a tool along a desired cut line and eliminates scratch damage to the material being cut. The tool guide of the present invention also reduces splintering of the material being cut. Downward pressure by the hand-held power tool and guide supports wood fibers at the cut line, thereby preventing or reducing splintering.
The tool guide of the present invention includes a base plate, an adjustable tool guide rail, and a pivoting edge control bar. The base plate defines the cut line for the tool and protects the material being cut, as described above.
The adjustable tool guide rail can be moved relative to the edge of the base plate so that tools of various sizes can be used with the guide.
The pivoting control bar can be set at right angles to the base plate edge or at angles to the base plate edge to provide accurate and consistent cut line angles without the need to calculate the resulting dimensions of the material to be cut.
REFERENCES:
patent: 2719548 (1955-10-01), Mitchell
patent: 2773523 (1956-12-01), Hopla
patent: 4125942 (1978-11-01), Horner et al.
patent: 4281572 (1981-08-01), Stovall
patent: 4483071 (1984-11-01), te Kolste
patent: 4607434 (1986-08-01), Francis
patent: 4611407 (1986-09-01), van Gorp
patent: 4901444 (1990-02-01), Maschmeier
patent: 5472029 (1995-12-01), Ketch
Gommper Brion
Pew Rex
Fulton Christopher W.
Smith & Amundsen
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