The present invention relates to a tool for splitting or “breaking” drywall board or similar planar material after the desired cut has been scored. Drywall is a common building material that is typically formed by a layer of gypsum plaster pressed between two thick sheets of paper and then the composite is kiln dried. Drywall is generally used for the finish construction of interior walls and ceilings. Drywall is also commonly known as gypsum board, wallboard, plasterboard, Sheetrock® (a trademark of United States Gypsum Company), or simply board.
The present invention relates to an apparatus which can be utilized for cutting drywall material. More particularly, this invention can be customized to suit a plurality of drywall lengths and sizes. The present invention also has a means for attaching a pole to the existing handle to provide for an extended reach or use of the device.
Typically, a T-square or tape-measure would be set on the top edge of a sheet of drywall in order to establish the required measurement and location of a desired cut on the drywall sheet. A utility knife would then be run along the side of the “T” or held at the end of the measuring tape to score the cut through the outer paper laminate on one side of the board. The user would then “snap” the drywall material backward to break the drywall along the score line. This rather uncontrolled application of break forces often results in debris, broken edge material and otherwise less-than-optimal board edge quality requiring application of time-consuming edge-dressing techniques or resulting in gaps in the adjoining sheets of drywall.
Because of their size, and the large surface area generally being covered by drywall sheets, drywall construction requires multiple sheets to be adjoined together in an abutting manner. To accomplish the necessary multiple flush abutments between adjoining drywall sheets, while accommodating the geometric requirements of the surface being covered, a drywall worker must make repetitive cuts in the drywall that are true, straight and of sound edge structural integrity over long distances. The industry has adopted the typical practice of using some type of cutting “guide” to create a straight score cut line on one side of the drywall in order to just break through the paper laminate and then secondarily applying a force on both sides of the score line while coincidentally applying an opposing force on the drywall board on the opposite side of the drywall and approximately behind the score cut in order to “snap” the interior layer of gypsum plaster. A standard utility knife is utilized to make both the initial score cut and the final cut through the second layer of paper laminate after the snap has occurred to complete the separation.
Many tools, devices and specialized cutters have been designed and manufactured to aid in the cutting of a specified size of drywall. However, these tools and devices are complicated and typically make the scoring or cutting of drywall very cumbersome. Furthermore, these tools and devices generally do not assist in breaking the board after the initial score is made and such tools and devices generally do not improve the quality of the resulting break.
In one example of the prior art, U.S. Pat. No. 5,600,892 to Peugh discloses a rather intricate apparatus for simultaneously cutting both sides of a drywall sheet by adjusting parallel cutter holding support columns at the same distance from a drywall board edge on which a guide assembly is positioned and traversed in order to accomplish the cut. The device must be carefully and evenly slipped over the edge of the drywall board in order to avoid inadvertent board edge breakage or damage causing waste. Such careful manipulations are cumbersome and time consuming for the worker.
In another example of the prior art, U.S. Pat. No. 6,289,594 to Wrobbel discloses a device comprising a U-shaped channel with an integral flat stem section which incorporates a plurality of guide apertures for marking or guiding a utility knife as the U-shaped channel is moved along a drywall board edge. This device is only useful for marking or performing the initial score cut and is not intended to be, nor in practice is, of any aid in the snapping of the board. Similarly, U.S. Pat. No. 7,481,001 to Rao discloses a T-square configured with a plurality of rollers contained in a U-shaped member to facilitate rolling along the edge of a drywall sheet while the measuring “ruler” section, which lies flat on the drywall board surface to be cut, incorporates an adjustable blade holder and cutting blade. Likewise, PCT Pat. Application No. WO 00/35641 to Walker discloses an apparatus comprising a U-shaped board edge locating means which supports a graduated spacer bar in a T-shape on which a slideable cutting device is located. Again, these devices are merely intended for marking and performing the initial score cut and are not intended to be, nor in practice are, of any aid in the snapping of the board. In yet another example of prior art, U.K. Pat. Application No. GB 2307879 to Santucci discloses an upper plate, lower plate and intervening block to define a slot in which the edge of a drywall board may be inserted but only for the purpose of securing a tool such as a spirit level or a ruler.
It is an object of the present invention to allow for making improved edge quality square cuts in a plurality of lengths with a drywall splitter after the board has been scored by positioning the device of the present invention directly onto the edge of drywall material adjacent and parallel to the intended cut. With such a device engaged on the board edge, followed by applying a small amount of force to a centrally located handle, a uniform breaking force is applied perpendicular to the plane of the drywall sheet causing a bending moment which is at all times parallel to the score cut, causing the drywall to snap making a clean cut with minimal debris and/or breakage to the existing drywall material.
The preferred embodiment of the present invention comprises a single J-shaped channel intended to engage the edge of the drywall board, and a substantially perpendicularly affixed handle centrally located on the bottom of the J-shaped channel and extending substantially in the opposite direction from pocket of the J-shaped channel. This J-shaped section comprises a Back Plate, a relatively shorter Front Plate, and a bottom section or Middle Holding Segment; the Back Plate connected to the Middle Holding Segment at a substantially right angle; and the Front Plate connected to the Middle Holding Segment at a substantially right angle and substantially parallel to the Back Plate. The Handle may be fixed to the J-shaped channel by any number of traditional methods such as, but not limited to, being molded in one piece, welded, mating mechanical threads, clamped, bolt and screw or spring loaded detent button. The removable Handle options facilitate ease of transport and storage in typical toolboxes, buckets, etc.
In an alternative embodiment of the present invention, a second J-shaped channel is located back-to-back with the first described single J-shaped channel, along the longer Flange described as the Back Plate above, and more specifically the Central Flange in the double J-shape embodiment, such that the pockets formed are substantially parallel to each other with the pocket openings facing in substantially the same direction. A substantially perpendicularly handle is centrally affixed on the bottom of the double J-shaped channels and extending substantially in the opposite direction from pocket openings of the double J-shaped channels. The double J-shaped embodiment provides for convenient drywall thickness variation accommodation as well as a choice in the optimal engagement Flange length for the cut being performed.
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments therein disclosed merely exemplify the invention which may be embodied in other specific structure. While the disclosed preferred embodiments have been described, the details may be changed without departing from the invention, which is defined by the claims.
Referring to the drawings, wherein like referenced characters designate corresponding parts throughout the several figures, a preferred embodiment of the invention 10 is shown in
As shown in
In a preferred embodiment, the back plate 16 is taller than the frontal plate 18 in order to apply and distribute the snapping force over a large area of the board. The middle holding segment 20 ensures that the splitter 10 is always normal to the edge of the board being cut and parallel to the score line while the shorter frontal plate 18 imposes a clamping force which locks the splitter 10 tool onto the board 30 when a force is applied to the handle 14. The interior surfaces of the back plate 16 and frontal plate 18 may be tapered, draft angled or rounded 19 to aid in guiding the engagement of the device 10 onto the board 30. Further, in the preferred embodiment, the top corners at each extreme end of the back plate 16 and frontal plate 18 have been rounded 17 or incorporate other geometry to guard against inadvertent personal injury and/or scaring or damaging of the board 30 while engaging or manipulating the device 10.
In alternative embodiments, the handle 14 may be removeably joined to the bottom surface 22 of the J-shaped holding head channel 12 by any number of known conventional means such as, for example, a nut and bolt, male/female receptacles, twist lock mechanism, spring locks, etc. to form a hand-tool sized device or simply for ease of packing and transport including inside toolboxes and tool buckets, etc.
The handle 14 configuration is not limited to the depicted hollow tube 21; however, the tube facilitates the easy insertion of and extension pole if desired. Such optional handle 14 extensions can also be accomplished in any number of the traditional methods such as being threaded like a broom handle, pinned, sleeved, keyed or sprung loaded detent button to facilitate extended reach or use of the device. The handle 14 may also incorporate a machined, molded or slip-on style hand-grip such as is used on bicycle handlebars.
When a slight force is applied to the centrally located handle 14, this force is transmitted over the entire square area defined by the length L1 and the height L2 of the back plate 16 of the J-shaped holding fixture 12 to ensure that a uniform breaking force is applied perpendicular to the plane of the drywall sheet 30. As shown in
An alternative embodiment is shown in
The principal advantage of the double J-shaped holding fixture 42 is that each L4 and L5 can be optimised for two different size board 30 thicknesses or range of thicknesses. In the preferred embodiment, the back plate 43 is longer than both the first frontal plate 44 and the second frontal plate 46 in order to apply and distribute the snapping force over a large area of the board 30. Further, first frontal plate 44 length L3 and the second frontal plate 46 length L6 can likewise be varied in length to correspond to their particular board 30 gap width L4 and L5 respectively. The middle holding segment 45 ensures that the splitter 41 is always normal to the edge of the board being cut and parallel to the score line, while the shorter frontal plate 44 or 46 imposes a clamping force which locks the splitter 41 onto the board when a force is applied to the handle 14A.
A preferred embodiment of the device is fabricated from metal, preferably light weight aluminum; however, any suitably rigid material will suffice. A device fabricated from metal may be formed by any number of known means such as by machining, stamping, forming, shaping, casting, extrusion and the like. The device also may be fabricated from suitably hard plastic or resin and formed by any number of known means such as by mold injection, extrusion, and the like.
Priority and benefit of earlier filing date of provisional application Ser. No. 61/212,113 filed Apr. 7, 2009, is claimed.