Patent Application
20200047362
This invention relates to cutting drywall generally and more particularly to such a drywall cutting tool which measures and aligns the guides with the cutting tool.
It is known that when scoring or cutting (collectively herein cutting) wallboard materials such as gypsum board, wallboard, plasterboard, insulation board, or like materials particularly in construction applications that time to perform cutting operations can be reduced and quality of cut increased when using cutting tools referenced to an edge of the wallboard material as in the case of a T-Square guided knife.
Cutting of wallboard needs to be quite accurate in most cases as the material is often used in finishing interiors of buildings where fit ultimately affects the quality and appearance of the finish.
Furthermore, the cutting of wall board materials should be quick and easy to maximize installer productivity and reduce overall cost of installation. In most cases, wallboard materials can be cut by first scoring the surface, and then bending the board along the score line to break the board.
Scoring a long line of 4 feet, typical gypsum board width, or even longer lines of 8 to 12 feet or more can be difficult without a referenced guide. Long straight edges often get bent and malformed due to miss-handling during normal construction work and transportation between job sites.
Several attempts aimed at resolving this challenge have been made. One of the attempts was a board cutter including a T-Square and a common utility knife mounted to a slider which rides along the long leg of the T-Square and is fixed at a position by means of a clamp mechanism as in a thumb screw. The common utility knife is connected to the slider by way of a pivotal pin and clamped into a depth of cut position again using a thumb screw arrangement.
One of the primary drawbacks is that is difficult to cut the full face of a wallboard from edge to edge as the T-Square runs out before the knife has scored the whole length of the surface. This is particularly evident when cutting a wallboard while it is standing on end as when leaning against a wall, the leading end of the head of the T-Square is blocked by the floor or ceiling preventing the knife from reaching the edges closest to the obstructing floor or ceiling.
The problem of the guiding member or T-Square head of the scoring tool reaching the end of the wallboard sheet ahead of the cutting tool in either direction has long been problematic that others have attempted to resolve.
Reference will now be made in detail to the present preferred embodiments, examples of which are illustrated in the accompanying drawings. All terms in the plural shall also be taken as singular and vice-versa. Further, any reference to be shall also be applicable to she and vice-versa. With reference to the drawings wherein like numerals represent like parts throughout the figures.
Further, the flanged plate 9 also has a screw-down clamp handle 3 located between the guide tracks 2. The screw-down handle 3 has a threaded portion 4 and a foot 10. The screw-down handle 3 is turned in the clock-wise direction to turn the threaded portion 4 to apply pressure by the foot 10 of the screw-down handle 3. When the screw-down handle 3 is turned counter-clockwise, the threaded portion 4 unscrews and the foot 10 of the screw-down handle 3 away from the flanged plate 9.
The screw-down handle 3 is coupled to the flanged plate 9 by a pivoting arm 6. The pivoting arm 6 has a connecting point to the screw-down handle 3 where the pivoting arm 6 is located at the threaded portion 4 of the screw-down handle 3 at a threaded joint pivoting point 7. The pivoting arm 6 is coupled to the flanged plate 9 by a support post 8. The support post 8 has a hinge 5. The hinge 5 is coupled to the pivoting arm 6 to allow the pivoting arm 6 to be manipulated easily. In the exemplary embodiment, the hinge 5 is coupled to the pivoting arm 6 furthest away from the threaded joint 7.
Referring now to
The ruler handle 21 also has a knife blade 23. This knife blade 23 is used to score drywall as the elongated flat ruler 20 is moved by the ruler handle 21 along drywall at a predetermined length. This coupling of the knife blade 23 and the ruler handle 21 prevents the knife blade 23 from moving in a direction away from the elongated flat ruler 20, thus the drywall scoring is straight and clean.
Moving now to
The support bracket has a flanged plate 9. The flanged plate 9 has a plurality of guide tracks 2 on an upper surface 11. In the exemplary embodiment, the guide tracks 2 are parallel.
Further, the flanged plate 9 also has a screw-down clamp handle 3 located between the guide tracks 2. The screw-down handle 3 has a threaded portion 4 and a foot 10. The foot 10 of the screw-down handle 3 is presented not against the flanged plate 9. The screw-down handle 3 is turned in the clock-wise direction to turn the threaded portion 4 to apply pressure by the foot 10 of the screw-down handle 3. When the screw-down handle 3 is turned counter-clockwise, the threaded portion 4 unscrews and the foot 10 of the screw-down handle 3 away from the flanged plate 9.
The screw-down handle 3 is coupled to the flanged plate 9 by a pivoting arm 6. The pivoting arm 6 has a connecting point to the screw-down handle 3 where the pivoting arm 6 is located at the threaded portion 4 of the screw-down handle 3 at a threaded joint pivoting point 7. The pivoting arm 6 is coupled to the flanged plate 9 by a support post 8. The support post 8 has a hinge 5. The hinge 5 is coupled to the pivoting arm 6 to allow the pivoting arm 6 to be manipulated easily. In the exemplary embodiment, the hinge 5 is coupled to the pivoting arm 6 furthest away from the threaded joint 7.
The knife blades 23a, 23b, 23c are shown attached to the ruler handle 21 at a 15-degree angle 23a, at a 45-50-degree angle 23b and at a 0-degree angle 23c. Although the previous mentioned angles for the knife blade 23a, 23b, 23c are the most commonly used angles when cutting drywall, one could have any angle for the knife blade 23a, 23b, 23c.
Now presenting
The support bracket 1 is placed onto the drywall sheet 30 on one of its long edges. A elongated flat ruler 20 is placed between the guides 2 of the support bracket 1. The first end 24 of the rule 20 is located on the drywall sheet 30. The ruler handle 21 is located at the appropriate length as determined in the previously mentioned measurement. The elongated flat ruler 20 is tightened at the guides 2 to prevent the elongated flat ruler 20 from sliding. The ruler handle 21 is then moved in one direction to score the drywall sheet 30 for later breaking the drywall sheet. Thus, the drywall sheet 30 will be the previously determined dimension.
The drywall cutting tool would, as an exemplary embodiment, be used as follows: The elongated flat ruler 20 has a knife blade 23 with a ruler handle 21 attached to the first end 24 of the elongated flat ruler 20. A support bracket 1 has a flat top portion with a flange 9 along one side. The support bracket 1 has a guides 2 on the top of the support bracket 1 that can receive the second end 25 of the elongated flat ruler 20 and the elongated flat ruler 20 is allowed to slide along the top of the support bracket 1 to any desired measurement length.
A screw-down handle 3 is attached to the top portion of the support bracket and pinches to secure the elongated flat ruler 20 in the guides 2 to keep the elongated flat ruler 20 at the desired measurement length.
The tool allows the support bracket to be placed on an edge of a drywall sheet 30 and the knife blade 23 is positioned at the desired measurement length so that the drywall sheet 30 may be cut at the desired measurement length by moving the support bracket 1 and the knife blade 23 together along the drywall sheet 30.
The features described with respect to one embodiment may be applied to other embodiments or combined with or interchanged with the features of other embodiments, as appropriate, without departing from the scope of the present invention.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
