Geometrical instruments – Gauge – Door and window
Reexamination Certificate
1999-11-24
2002-01-29
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
Door and window
C033S429000, C033S482000, C052S749100, C052SDIG001
Reexamination Certificate
active
06341427
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to tools used in building construction. More specifically, an easy-to-use hand-held tool enables rapid and precise location and installation of casing about windows or doors during installation.
2. Description of the Related Art
In the construction of buildings, it is common practice to frame portals such as window openings and doorways with lumber or other structural components. For the purposes of this disclosure, framing will be understood to maintain spacing and provide structural integrity, the framing often extending between an interior surface of a building structure and an exterior surface. Into the framing, a prefabricated door or window may be mounted and rigidly supported relatively quickly and reliably.
Because windows and doors can not be specified to an exact size, but instead will vary in dimension somewhat due to tolerances and other factors, and because further shimming may be required for leveling, the framing material is preferred to have a slightly larger opening than the window or door's outer perimeter. The resulting gap between rough framing and door or window jamb may be relatively large and quite unsightly. Various caulking and insulation may be applied into the gap to improve energy efficiency and building comfort, but this caulk and insulation only further add to the unsightly appearance in the vicinity of the rough framing and jamb. In view of the limitations regarding rough framing and materials adjacent the jamb, it would make little sense to spend the time necessary in preparation and cutting of wall board to be perfectly precise. To save time and to greatly simplify effort, wall board is only rough cut to the approximate dimension of the opening, and may also have an uneven edge. In summary then, the junctions between framing lumber, window and door jambs, and wall boards are quite unsightly.
To improve the otherwise unsightly appearance of an opening, it is common practice to finish the opening with decorative trim pieces that conceal the uneven edges, gaps, caulking and insulation. These decorative trim pieces, for the purposes of this disclosure and also commonly in the trade, are referred to as casing. Casing, usually fabricated from wood, is finished on three sides, while the fourth side will be concealed from view and so is commonly left unfinished. For the purposes of this disclosure, casing will not be limited to wood, but is instead defined herein to include plastics, metals and other materials provided for use as decorative trim about a portal. Where casing intersects or joins to form a right angle with a perpendicular casing piece, the intersection is most commonly cut diagonally, so that each casing is cut at a forty-five degree angle to the long side of the trim. The diagonal cut offers an improved appearance, while further insuring coverage and concealment of underlying seams and other unsightly details.
Because of the more desirable diagonal cut and the need for a well-fit, highly finished appearance, the preparation of casing for portals is quite difficult and undesirably time consuming. Windows are particularly difficult, since all four casing pieces must align perfectly, though doors also require two well-finished intersections and well spaced reveal about three surfaces. In the prior art, there are a limited number of methods and tools available to address this very old problem.
Among the earliest tools used for the installation of casing are rules and squares. These devices are first used to mark the desired location of each component, to next measure from the marks the dimensions that would be necessary, and then to mark raw material for cutting. Once the raw materials are marked, they are cut and placed. As it might appear, there are many opportunities for error and deviation from the exact dimensions using rules and squares. For example, measurement from marks is rarely more accurate than within a thirty-second of an inch, and may deviate by a sixteenth or more, depending upon the skill of the carpenter. Cutting is generally less precise than the measurement, due to kerfs, smoothness or roughness of the kerf, and other similar factors. Final placement will also vary, depending upon the viewing angle of the carpenter. For example, the original mark may have been drawn from a view looking to the right over the rule or square, while placement may occur looking over the casing from the left. This optical variation may be as great as the other possible variants. Finally, during the installation, the carpenter must prevent the casing from moving, which can also be very difficult.
While the deviations between measurement, cut and placement may cancel each other in some instances, in other instances these deviations will be additive. That is, if each individual deviation was one-sixteenth of an inch, the resulting total deviation may be one-quarter of an inch. For many applications in carpentry this deviation may not adversely affect the appearance or quality of the work. However, with casing such as used around windows or doors, where the junctions are at forty-five degree angles, these deviations become quite pronounced. Further complicating the issue is the need, with windows, to form four such junctions around the window. All too often, the intersections may be tight at one edge of the trim, such as the inside perimeter, but then be fully separated by the amount of the deviation at the other edge, such as the outer perimeter, resulting in a visual emphasis of the deviation. Unfortunately, the deviation may not be easily taken up at some other location, since all four corners must align at the same forty-five degree angle. This can lead to a frustrating and time-consuming removal of the casing and additional sawing to bring the individual trim pieces to a more exact fit.
Other more specialized tools have been developed to help with the installation of casings. For example, Erickson in U.S. Pat. No. 2,473,639, the contents incorporated herein by reference, illustrates a tool for marking a doorjamb to show where the door casing should be placed. Like rulers and squares, the Erickson gauge is quite helpful in marking the proper location for the casing. However, as also required with rulers and squares, the measurements must still be taken from those markings and the cuts made from the measurements, and then the casing applied as best as possible in alignment with the markings. Since the Erickson device leaves a scribe in the doorjamb, it is critical that the casing cover the marking as well, which may be fairly difficult to do consistently at a construction site.
More recently, Bear in U.S. Pat. No. 5,349,758, the contents incorporated herein by reference, illustrates a more complex square capable of performing marking in a fashion similar to the Erickson device. In the Bear patent, a pencil may be inserted into one of a number of preselected holes, and the square slid along a door or window jamb to draw a line. While the pencil is an improvement over the scribe of the Erickson device, there is still a need to mark the entire jamb, and subsequently measure and cut the material, and finally very carefully align the material to the marks and secure the material thereto. Furthermore, the Bear square is rather large and unwieldy, making it undesirable to store and transport, and more difficult to use at the construction site than would be preferred.
Born in U.S. Pat. No. 3,293,764, also incorporated herein by reference, provides a construction gauge that clamps into doorways and windows, to assist with placement and also, in one embodiment, cutting of window and doorway casing. A spring clamp holds the gauge on both sides of the opening, and edges are provided for a predetermined offset. In one embodiment, a forty-five degree angle is also provided which ensures accurate placement of casing. Nevertheless, while the Born patent offers many advantages, there still remain several limitations. First, because the Born gauge is spring mounted, seve
Fulton Christopher W.
Watkins Albert W.
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