| United States Patent | 3,888,068 |
| Zambrano | June 10, 1975 |
Hole cutting apparatus
Abstract
An apparatus for cutting holes in wallboard has a handle with a dogleg and a heavy, rectangular, flat anvil connected to the end of the handle. Sharp, straight-walled cutters extend downward from the perimeter of the anvil, forming a rectangular, box-like structure. Holes are formed through the anvil to permit the escape of air during the cutting process and to permit the removal of the cut out piece of wallboard from the cutter box. Two pointed pins, extending downward from the anvil slightly beyond the cutters, help to hold the apparatus in position before the cutters are driven through the wallboard by striking the anvil.
| Inventors: | Zambrano; Damaso P. (Honolulu, HI) |
| Appl. No.: | 05/390,773 |
| Filed: | August 23, 1973 |
| Current U.S. Class: | 30/358 |
| Current International Class: | B26F 1/38 (20060101); B26f 001/32 () |
| Field of Search: | 30/5.5,358,359,361,367,16,316 |
| 1483661 | February 1924 | Hall |
| 2830662 | April 1958 | Marcum |
| 2964882 | December 1960 | Hudson |
| 3381376 | May 1968 | Ames |
Assistant Examiner: Peters; J. C.
Attorney, Agent or Firm:
I claim:
1. A wall board hole cutting apparatus comprising
an anvil plate,
an annular cutting rim, attached to a perimeter of the anvil plate extending perpendicularly downward from a principal plane of the anvil plate, where a lower edge of the annular cutting rim is a cutting edge,
an elongated handle member, with one end attached to the edge of the anvil plate, extending away from the anvil plate in a direction generally parallel to the plane of the anvil plate with a portion of the handle bent upward away from the plane of the anvil plate and with the handle bent a second time to return the configuration generally parallel with the plane of the anvil plate with a distal portion of the elongated handle member displaced upward from the plane of the anvil plate so that the handle may be encircled by a hand with backs of fingers resting on wall board while the annular cutting rim rests on a sheet of wall board, whereby the hole cutting apparatus is held in position on the wall board during a cutting process;
whereby holes are cut in wallboard by manually positioning the hole cutting apparatus with the elongated handle member and by driving the annular cutting rim through the wallboard by impacting an upper face of the anvil plate.
2. The hole cutting apparatus of claim 1 wherein the anvil plate is equipped with apertures passing through the anvil plate; whereby, air trapped between the anvil plate, annular cutting rim, and the wallboard during the cutting process is expelled, and whereby a probe may be inserted through the anvil plate to dislodge wallboard cuttings wedged within the annular cutting rim and the anvil plate.
3. The hole cutting apparatus of claim 1 wherein the elongated handle member extends parallel to the plane of the anvil plate from the elongated handle member's point of attachment with the anvil plate, bends upward so that a portion of the elongated handle member is perpendicular to the plane of the anvil plate, held in position during the cutting process.
4. The hole cutting apparatus of claim 1 further comprising locator pins fixed to the hole cutting apparatus, extending perpendicularly downward to a point below the sharpened cutting edges, and pointed at their extreme lower ends; whereby, the hole cutting apparatus is located in position on a sheet of wallboard prior to cutting by inserting the points of the locator pins into the sheet of wallboard.
5. The hole cutting apparatus of claim 1 further comprising locator pins fixed to the lower face of the anvil plate and extending perpendicularly downward to a point below the sharpened cutting edges, and pointed at their extreme lower ends; whereby, the hole cutting apparatus is located in position on a sheet of wallboard prior to cutting by inserting the points of the locator pins in to the sheet of wallboard.
BACKGROUND OF THE INVENTION
The invention described herein concerns a device for cutting holes in wallboard by driving a hand held, annular cutting edge through the wallboard. Conventional methods for cutting holes in wallboard require steps of marking rectangles and then cutting rectangular holes with wallboard knives. Other known wallboard cutters use receptacle boxes behind sheets of wallboard to position cutting tools. It is the object of this invention to provide a superior hole cutting apparatus employing a simplified method of positioning the cutting edge.
A collection of devices of the type known in the prior art is found in the Official U.S. Patent Office Classification of Patents, particularly in Class 30, subclass 287, 358, 360, 361, 367 and 368. Examples of such devices are found in U.S. Pat. Nos. 2,787,324; 2,830,662; 3,251,130; 3,381,376; and 3,391,460.
In U.S. Pat. No. 2,830,662 a generally rectangular cutting tool is shown. The cutter has a heavy plate with holes and a perpendicular anvil-handle combination. Two prongs attached to a receptacle box extend through the wallboard from behind the wallboard sheet to guide the cutter.
U.S. Pat. No. 3,251,130 shows a two-part cutter. A rectangular cutting tool with a beveled sharp edge is positioned in a stud-mounted receptacle box. A wallboard is placed against the cutting tool. An anvil is placed on the wallboard opposite the cutting tool and is struck, driving the wallboard onto the cutting tool.
Other patents show complex cutters with pairs of serrated cutting edges which are driven simultaneously through both sides of the wallboard.
A need exists for a hole cutting apparatus for wallboard which can be positioned manually without the aid of devices placed behind the wallboard. A need exists for a simply constructed hole cutting apparatus which is convenient to carry, position, and operate.
SUMMARY OF THE INVENTION
The present invention is an apparatus for cutting holes in wallboard consisting of an anvil plate and an attached elongated handle member. An annular cutting rim with a sharpened lower edge is attached to the perimeter of the anvil plate and extends downward from a principal plane of the anvil plate.
The elongated handle member is attached to an edge of the anvil plate. The handle extends away from the anvil plate in a direction generally parallel to the plane of the anvil plate. A portion of the handle is displaced upward from the plane of the anvil plate so that the handle may be grasped by a hand while the annular cutting edge is contacting a sheet of wallboard. The bend in the handle is of appropriate size so that the backs of the fingers or hand rest against the wallboard to steady the cutter during alignment.
The anvil plate is of sufficiently sturdy construction that it may be struck directly with a hammer or drywall hatchet to drive the annular cutting edge through the wallboard. In a preferred embodiment the anvil plate is formed with apertures permitting the expulsion of air trapped between the anvil plate, annular cutting edge and wallboard during the cutting process. The apertures also permit a probe to be inserted through the anvil plate to dislodge wallboard cuttings wedged within the annular cutting edge and the anvil plate.
The annular cutting rim is a sharpened, straightwall cutter extending downward from the perimeter of the anvil, forming a box-like structure with an open face. In one configuration the sharpened lower edge of the cutting rim is formed by beveling the straight walls of the cutter from both vertical sides. In a preferred embodiment, the outer wall is straight and the innerwall is beveled to meet the outer wall in a sharp lower edge.
In a preferred embodiment the anvil plate and the annular cutting edge are rectangular and are used for cutting rectangular holes for electrical receptacle boxes. In this configuration the hole cutting apparatus is positioned by juxtaposing edges of the rectangular anvil plate with vertical and horizontal measurement lines drawn on a surface of the wallboard.
In another preferred embodiment, pointed locator pins are attached to the cutting apparatus and are extended downward below the cutting edge so that the hole cutting apparatus can be fixed on the surface of the wallboard before cutting, by inserting the points of the locator pins into the wallboard. In one form of the preferred embodiment, two locator pins are attached to the anvil plate within the box-like structure.
An embodiment of the present invention employs a pair of "T" square rules attached to the anvil plate. The cap portions of the preset length T square rules are engaged with edges of the wallboard sheet and are used to determine hole locations on the surface of the wallboard by positioning the cutter predetermined distances from edges of the wallboard.
An annular cutting edge is capable of being employed to cut a hole in wallboard for a receptacle box whose body is larger than the annular cutting edge. To accomplish this, the annular cutting edge is positioned on the wallboard and then is driven through the sheet of wallboard from only one side. The annular cutting edge pierces a first side of the sheet of wallboard and then breaks through the second side of the sheet. The passage of the annular cutting edge through the second side of the sheet of wallboard enlarges the mouth of the hole on the second side by fragmenting the perimeter of the hole. This enlargement permits the hole mouth on the second side to accept a receptacle box whose body is larger than the hole mouth on the first side.
An object of the present invention is to provide a hole cutting apparatus which may be positioned by a hand held handle, vertically and horizontally offset from the anvil plate. The location of the handle facilitates the aligning of the anvil plate with measurement lines drawn on the surface of the wallboard. It also permits the cutting apparatus to be safely held at a point remote from area at which the apparatus is struck by a hammer or drywall hatchet. Because the handle is displaced upward from the plane of the anvil plate, the handle can be encircled by the hand during the time that the annular cutting edge is being driven into the wallboard.
Another object of the present invention is to provide a hole cutting apparatus consisting of a box-shaped anvil plate and cutting edges equipped with apertures for relieving air pressure built up within the box-like structure as the apparatus is driven into the wallboard. The same apertures may be used to insert probes to dislodge trapped wallboard cuttings.
Another object of the present invention is to provide a hole cutting apparatus with T square appendages which are used to precisely position the annular cutting edge.
Another object of this invention is to provide a method for fitting receptacle boxes to holes cut in wallboard. A fragmented hole mouth on the side of the wallboard where the cutting edge exits accomodates a receptacle box body larger than the hole mouth on the side of the wallboard that the cutting edge first pierces.
These and other objects and features are apparent in the drawings, specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of the hole cutting apparatus of the present invention showing the apparatus driven into a sheet of wallboard.
FIG. 2 is a perspective view of a sheet of wallboard showing measurement lines on the surface of the wallboard.
FIG. 3 is a perspective view of a sheet of wallboard showing two types of cut holes which may be made with the hole cutting apparatus of the present invention.
FIG. 4 is a perspective view of the hole cutting apparatus of the present invention.
FIG. 5 is a cross-sectional side elevation of the hole cutting apparatus of the present invention.
FIG. 6 is a bottom elevation of the hole cutting apparatus of the present invention showing the locations of the cutting edge and locator pins.
FIG. 7 is a detail of T square rules attached to an anvil plate of the cutting apparatus.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1, a hole cutting apparatus is generally denoted by the numeral 1. The anvil plate 2 is attached to the annular cutting rim 3. The sharpened cutting edge 4 of the annular cutting rim is shown contacting the outer covering 13 of a laminated wallboard sheet 12. An elongated handle member 7 is attached to the anvil plate. The handle member is formed with a dogleg bend 6 to permit the apparatus to be hand held during the positioning of the apparatus and the driving of the cutting edge through the wallboard. A drywall hatchet 20 is shown impacting the anvil plate. The head and handle of the hatchet are denoted by numerals 21 and 22 respectively.
FIG. 2 is a perspective view of a sheet of wallboard 25, showing a vertical measurement line 27 and a horizontal measurement line 29. A rectangular anvil plate of a preferred embodiment of the present invention would be positioned over the intended location for the hole 30 by juxtaposing edges of the anvil plate with the measurement lines.
In FIG. 3 a sheet of wallboard is denoted by the numeral 35. A hole cut by driving an annular cutting edge completely through the sheet from one side is denominated 36. The fragmented hole mouth or "blast" 39, caused by the exit of the annular cutting edge, will accept a receptacle box with a body larger than the entrance hole mouth on the opposite side of the sheet of wallboard. A hole 40 cut by driving an annular cutting edge into the wallboard sheet from both surfaces of the sheet has side walls which are roughly perpendicular to the principal surfaces of the sheet.
FIG. 4 is a perspective view of a hole cutting apparatus 50 showing a preferred embodiment of the present invention with two apertures 51 in the anvil plate. The apertures permit the escape of air trapped between the anvil plate 53, annular rim 55, and wallboard during cutting. The apertures also permit a probe to be inserted through the anvil plate to dislodge wallboard cuttings wedged within the anvil plate and annular cutting rim. The figure also shows a preferred point 52 for impacting the anvil plate to drive the annular cutting edge 57 through a sheet of wall board. The elongated hangle member 59 with a dogleg bend 58 is attached to the anvil plate.
FIG. 5 shows the shape and position of the locator pins 56 of the preferred embodiments which are attached to the anvil plate. The locator pins extend below the cutting edge 57 so that they may be inserted into the wallboard to position the hole cutting apparatus before the cutting operation begins. The figure also shows the structure of cutting edges where the straight, vertical walls of the annular cutting rim are beveled from both the interior and exterior vertical walls to form a cutting edge.
FIG. 6 is a bottom view of the hole cutting apparatus showing the approximate location of the apertures 51 and locator pins 56 of the preferred embodiment.
FIG. 7 is a detail of T square rules attached to an anvil plate of the cutting apparatus. The anvil plate 60 is attached to rule 62 of T square 64 for precisely positioning the anvil plate 60 on wall board 35.
While the invention has been described with reference to specific embodiments, it will be obvious that modifications and variations may be constructed without departing from the spirit and scope of the invention. The scope of the invention is described in the following claims.
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