Cutlery – Cutting tools – With guard and/or guide
Reexamination Certificate
2000-12-26
2003-09-02
Shoap, Allan N. (Department: 3724)
Cutlery
Cutting tools
With guard and/or guide
C030S294000, C030S287000, C083S745000
Reexamination Certificate
active
06612035
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to hand tools for cutting various articles, and more specifically to a cutting tool including guide means for cutting or scoring across the length and width of a drywall sheet or board. The present tool includes an adjustably installable cutting blade body for installation on a guide in one of two mutually normal orientations to permit cutting or scoring in two mutually perpendicular axes.
2. Description of the Related Art
The use of gypsum wallboard or drywall has become the most common means of finishing the interior structure of most building structures. The installation and finishing of drywall boards or panels takes relatively little time for experienced workers, and provides a smooth surface for further finishing. Cutting drywall panels to size remains one of the more labor intensive aspects of working with the material, due to the different tools generally used in the measuring, marking, and cutting operations.
Generally, the cutting of drywall panels to any given shape or size involves about the same number of steps and time, with the panel being measured and marked for the cut, a straightedge aligned with the mark(s), and a separate cutting or scoring tool being drawn along the mark, as guided by the straightedge. The board is then broken along the scored line to separate the core material along the scored line, and the uncut backing paper is cut through to separate the two panels. This procedure is applicable to both non-rectangular and rectangular panels.
Yet, due to the rectangular configuration of most interior walls and surfaces, most drywall panel cuts are orthogonal and result in rectangular panels of various sizes. Even though forming such rectangular panels should be a relatively straightforward process, the same relatively involved procedure is used as for other panel shapes, resulting in considerable time spent on relatively simple configurations. Also, when the interior of a structure is constructed, the walls are nearly universally a single predetermined height. If this height is different than the length of a standard drywall panel, then the panel must be cut (or an additional piece added) to complete the coverage of the wall. It will be seen that each panel must be cut exactly the same, yet the measuring and cutting process conventionally involves the same number of steps and time for each cut, as for a series of different cuts to form different sizes and shapes of panels. The time spent conventionally in making a series of identically configured panels, adds considerably to the time and expense required for such work.
Accordingly, a need arises for a drywall cutting tool which simplifies the layout of orthogonal cuts to drywall panels. The present tool essentially comprises a T square, with the elongate blade of the square always remaining parallel and perpendicular to the edges of the rectangular board when the crossmember is aligned along one edge. The removable cutting body may be turned in one of two mutually orthogonal directions (four positions), so that the cutting blades are always aligned parallel and perpendicular to the edges of the board, thus guaranteeing a straight and true cut every time. The present tool requires only measuring and marking the board and properly aligning the guide, with the present tool being used for both measuring and guiding the cutting or scoring blade.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 4,956,919 issued on Sep. 18, 1990 to James P. Granger, titled “Drywall T-Square,” describes a device which is not strictly a T-square, due to the relative movement and disassembly of the two blades from one another. One rule is fixed relative to the drywall panel, with a second relatively movable rule having a series of lateral slots therethrough. A conventional utility knife is inserted through the desired slot and the movable rule is drawn over the panel, with the slot through which the knife blade extends, acting as a guide. The knife used with the Granger guide cannot be positioned for orthogonal cuts; the entire assembly must be repositioned along a perpendicular edge of the board.
U.S. Pat. No. 5,083,375 issued on Jan. 28, 1992 to Larry Helm, Sr., titled “Drywall Cutting Device,” describes a T-square like device in which the lower portion of the stem of the device may telescope for extension as required. Two separate tracks are provided, with the cutting head being slidably affixed to the two tracks of the extension and extending thereacross. The device uses a single conventional knife blade, rather than the spaced apart dual roller blades of the present drywall cutting tool. The Helm, Sr. tool is relatively flexible in comparison to the present tool, due to the relatively narrow telescoping arms of the Helm, Sr. tool and their spacing. The positioning of the cutting elements of the present tool outside the channel of the stem portion of the T, results in greater rigidity and more accuracy in forming a cut.
U.S. Pat. No. 5,231,764 issued on Aug. 3, 1993 to Kenneth Chang, titled “Cutter For A Plasterboard Sheet,” describes a cutting device which clamps removably to a conventional T-square. The device is relatively simple, and thus has many limitations in comparison to the present drywall cutting tool. The knife holding body secures to the stem of the T-square in only one direction, with the knife blade always oriented normal to the stem of the square. Thus, the Chang device must be moved to a perpendicular second edge of the drywall sheet or board, in order to make a cut parallel to that edge or perpendicular to the first edge. Only a single conventional utility or drywall knife blade is provided by Chang, as compared to the dual spaced apart roller cutting elements of the present drywall cutting tool invention.
U.S. Pat. No. 5,265,342 issued on Nov. 30, 1993 to Joseph D. Lang, Jr., titled “Drywall Cutting Tool,” describes a device having a relatively short edge guide for sliding placement along one edge of a drywall sheet, with a rod adjustably extending from the guide. A cutting tool is secured to the end of the rod. The relatively short edge guide permits the guide to rock at least slightly, thus resulting in the cutting tool holding rod moving arcuately somewhat relative to the guide edge of the drywall sheet. The cutting tool cannot be rotated relative to its attachment to the rod. All cuts are made parallel to the movement of the guide along one edge of the board, thus requiring the tool to be moved to a perpendicular edge of the board for a cut perpendicular to the first edge. Only a single conventional cutting blade is provided.
U.S. Pat. No. 5,471,753 issued on Dec. 5, 1995 to Bernardo M. Rodrigues, titled “Combination T-Square And Cutter,” describes a square with a stem blade having a relatively wide slot along its center, with a knife holder adjustably riding in the slot. The holder cannot be turned ninety degrees in the slot, due to the provision of locking extensions only in opposite edges of the holder, which engage cooperating notches on each side of the slot of the stem of the square (column 2, lines 44-47). Thus, the device is only capable of making cuts perpendicular to the slotted stem portion of the device; the entire device must be relocated for perpendicular cuts. Moreover, the device includes only an open saddle for holding the knife, with the operator being required to hold the knife in place, unlike the present invention.
U.S. Pat. No. 5,600,892 issued on Feb. 11, 1997 to Glenn H. Peugh et al., titled “Dual Side Drywall Panel Cutter,” describes a tool in which dual opposed arms extend downwardly from a single edge guide component, with each arm carrying a cutting blade. The device provides simultaneous cutting of the backing on opposite sides of wallboard material, when the two blades are positioned directly opposite one another. The cutting plane of the blades is fixed normal
Brown Patrick H.
Good William D.
Litman Richard C.
Prone Jason
Shoap Allan N.
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