Abstract:
A material removal system enabling the installation of electrical outlet boxes and junction boxes among others, includes a platen for attaching to a vibrating movement, a blade with teeth having any circular or non-circular cutting edge which attaches to the platen that vibrates the teeth multidirectionally. The system enables rapid material removal and produces a clean rectangular aperture requiring little or no modification prior to installing an outlet box.

Description:
FIELD 
       [0001]    The present invention relates generally to hole cutting methods and devices for producing an aperture of a shape and size to receive electrical outlet boxes, junction boxes and other inserts. 
       BACKGROUND 
       [0002]    Outlet boxes are installed typically in drywall or other sheet material, at the time of manufacturing, construction or for remodeling purposes. While determining a cut-out position in drywall for an outlet box is a simple matter during new construction owing to the visibility of the studs and the outlet box itself which is typically affixed to a stud, a number of problems present themselves when installing junction boxes in a remodeling scenarios. While drywall, prior to mounting on studs, can be marked and cut with a saw or utility knife from both sides, once mounted to studs, installation of an outlet box is limited to cutting through the outer facing surface of the drywall which increases the likelihood of a misplaced cut and an irregular aperture that must be repaired before or after insertion of the junction box, causing time loss for a contractor manufacturer or homeowner. Several devices have been described for cutting rectangular holes in drywall in order to mount electrical junction boxes. U.S. Pat. No. 5,797,189 to Gilbert describes a tool for cutting rectangular holes in drywall for new construction that uses a template with guide pins that are inserted into the pre-threaded apertures of electrical outlets and junction boxes in order to properly position and guide the cutting tool. U.S. Pat. No. 5,048,190 to Aurness et al., describes a tool that is chucked to a hand drill for cutting rectangular holes in drywall. While the foregoing devices are no doubt useful for their intended use, multi-bladed configuration introduces complexity and when mounted to a drill, and requires that the user manipulate a device having considerable distance between the power switch or handhold and the cutting edge which reduces control over the material removal process. It would be desirable to provide a motorized means of cutting holes for the installation of electrical outlet and junction boxes that would remove a single portion of material defining an aperture for an outlet box, junction box or other insert. It would also be desirable to produce an aperture possessing clean corners that require no additional modification of the aperture; for example, additional sawing or sanding, which is required with past hole cutting systems. Moreover, it would be desirable for the foregoing tool to be shaped and sized for easy manipulation and control over the cut. 
       SUMMARY 
       [0003]    The present invention relates generally to a system for cutting holes in a material such as drywall or any other construction material for the placement and installation of electrical outlet, junction boxes and other regular and irregularly shaped inserts of various types, and includes a powered blade having a cutting edge without gaps at the corners that produces a circular or non-circular aperture with clean corners that requires little or no additional modification; e.g., clean out or additional trimming prior to box installation. It should be noted that while particular embodiments depicted in this disclosure have a rectangular blade, any circular or non-circular shape can be used, for example, hexagons, octagons and rectangles with rounded corners. It should be noted that while the particular embodiments depicted in this disclosure have a rapid elliptical movement and variable speed RPM, other oscillating or vibratory movement is conceivable. Preferably, the RPM can range from 500-15,000. Also, the blade can possess contiguous teeth, or the teeth can have a slight gap at the corners or bends of the blade of whatever profile or shape. Whatever the shape of the cut, the powered blade agitates serrated teeth through the material being cut. At least one guide pin which is stationary relative to the motorized blade, transfers movement to the blade and stabilizes the cutting edge as it is plunged into the material. Regarding the oscillating movement, those having skill in the art will appreciate that there have been described a number elliptical or orbital movements in the field of sheet sanders. U.S. Pat. No. 3,375,616 to Scott et al., and U.S. Pat. No. 4,744,177 to Braun et al. are incorporated by reference herein. Other devices such as personal massagers possess similar elliptical and or orbital movements. Mechanical movements used in the forgoing, as well as others can be used to produce a multidirectional and/or vibrating movement suitable for use with the present invention. 
         [0004]    In one aspect of the present invention, a cutting assembly includes a replacement platen for a tool such as a motorized sheet sander, and a blade assembly which is attachable to the replacement platen. The ability to retrofit to existing sheet sanders or personal massaging devices is advantageous, as it reduces complexity and cost. 
         [0005]    In another aspect of the present invention, a blade assembly is attachable to an OEM platen for a sheet sander or personal massaging devices. 
         [0006]    In another aspect of the present invention, the cutting assembly includes a platen and a removable saw blade attachable to the platen, as part of a motorized tool with elliptical or orbital movement, similar to the movement employed by electric sheet sanders or personal massaging devices. 
         [0007]    In the foregoing aspects, at least one guide pin, preferably having a tapering end for piercing a material, does not vibrate with the platen, but is connected to the tool body. The pin stabilizes the tool body so that kinetic energy from the motor is transferred to the cutting edge while it is agitated through the material. 
         [0008]    It will be appreciated by those of ordinary skill in the art that the saw blade of the particular depicted embodiments can possess any number of teeth and any tooth profile including flat top teeth, combination teeth, alternate top bevel teeth and high alternate top bevel teeth. Set of the teeth can vary. The teeth can be alternately offset and possess an alternating side rake as well. Gullet dimension and kerf size can vary. The material of the blade can be carbon steel, carbide tipped, hardened steel or any material suited for material removal by cutting, piercing or sawing. Conceivably, the present invention can be adapted to use sanding, milling, piercing and grinding means as part of an agitating cutter. 
         [0009]    The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures wherein the scale depicted is approximate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is an exploded view of one embodiment of the present invention; 
           [0011]      FIG. 2  is an exploded view showing a rectangular blade  210  and blade coupling plate  214 ; 
           [0012]      FIG. 3  is a bottom perspective view of blade  210 , showing lip  211 ; 
           [0013]      FIG. 4  shows the mechanical linkage inside housing  230  with platen removed; 
           [0014]      FIG. 5  is an isometric view of a mechanical linkage housing  230  with attached platen  224 ; 
           [0015]      FIG. 6  is a plan view of one side of blade coupling plate  214 ; 
           [0016]      FIG. 7  is a plan view of the blade coupling plate when nested within blade  210 ; 
           [0017]      FIG. 8  is a top plan view of the platen of ( FIG. 5 ); 
           [0018]      FIG. 9  is a bottom up perspective view of the platen of ( FIG. 8 ); 
           [0019]      FIG. 10  depicts a number of exemplary saw tooth profiles; 
           [0020]      FIG. 11  depicts a bottom facing plan view of one embodiment according to the present invention with a cylindrically shaped blade. 
           [0021]      FIGS. 12   a  and  12   b  depict other embodiments with a tapered blade configuration and a arched blade configuration; 
           [0022]      FIG. 12   c  is an alternate embodiment according to the present invention wherein blade  210  has flanges  223  with fastening apertures for attaching the blade directly to platen  224 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference Listing 
       [0000]    
       
           100  material removal system 
           200  blade assembly 
           210  blade 
           211  blade lip 
           212  cutting edge 
           214  blade coupling plate 
           216  securing studs 
           218  locking fastener 
           220  securing apertures 
           220   a  fastener aperture 
           220   b  fastener aperture—platen 
           220   c  platen securing aperture 
           220   d  platen securing fastener 
           221  dust collection aperture 
           222   a  guide pin apertures 
           223  flange 
           224  platen 
           226  platen apertures 
           228  guide pins 
           230  mechanical linkage housing 
           231  spacer guides 
           232  guide pin support plate 
           233  offset bushing 
           234  bearing seat 
           236  mechanical movement 
       
     
       Definitions 
       [0048]    In the following description, the term “material removal” refers to any material typically used in construction or manufacturing which includes, but is not limited to drywall, sheet rock, plaster board and cement composition board. The term “insert” refers to any inserted item whether an outlet box or other article. The term “outlet box” is used interchangeably with “electrical outlet box”, or “electrical junction box.” The term “motorized” means a fuel powered motor or an electric motor, not depicted in the disclosure. The term “platen” refers to the typically flat element of tools such as vibrating sanders an the like that is connected to the mechanical movement that agitates, vibrates or otherwise moves the platen which is pressed against a workpiece. The terms “move,” “movement,” “agitating movement” or “agitating motion” refer to any orbital, pseudo-orbital, elliptical, oscillating or vibratory movement. It does not refer to linear reciprocating movement—back and forth motion, or so called random orbital movement common to hand held sanders and some personal massaging devices in which the pad or disc is spinning and simultaneously moving in an elliptical path. The term “substantially gapless” refers to the blade of the disclosure, and more specifically to the back of the blade into which teeth are formed having no gaps or only very small gaps at the bends or corners of no more than 3 mm. Unless otherwise explained, any technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The singular terms “a”, “an”, and “the” include plural referents unless the context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. The term “comprises” means “includes.” All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety for all purposes. In case of conflict, the present specification, including explanations of terms, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. 
         [0049]    Referring generally to  FIGS. 1 through 12   c,  a material removal system  100  enabling the installation of electrical outlet boxes, junction boxes and other inserts into drywall and other material, includes a platen  224  attached to an agitating movement  236  inside of housing  230 , a serrated blade  210  of rectangular profile attaches to the platen via blade coupling plate  214 . Studs  216 ,  218  are attached to platen  224  at one end, and at the other end attach to coupling plate  214  via apertures  220  in order to secure blade  210  to the platen. The platen is agitated by a motor driven offset bushing  233  which fits within bearing seat  234  formed on the underside of platen  224 . Blade securing apertures  220  while depicted as having a keyhole shape in  FIG. 1 , can be other shapes suitable for coupling with studs  216 ,  218 . Stud  218  is a locking fastener of similar design to securing studs  216  and passes though aperture  220   a  of the coupling plate, and threads into aperture  220   b  of the platen to secure the blade assembly and platen together in a sandwiched arrangement. Two guide pins  228  with tapering ends emerge from the linkage housing  230  which does not move with the platen. The pins are used to target a cut, pierce the material being worked and stabilize tool body so that energy is transferred to the blade as it vibrates though the material during the cutting process. 
         [0050]    Turning to  FIG. 1 , an exploded view shows a preferred arrangement for the various components of one embodiment of the present invention. At the bottom is a housing for mechanical linkage  230  that contains an eccentric cam causing platen  224 , to move. Platen  224  is attached to spacer guides  231  which move in concert with the platen when fasteners  220   d  are threaded into apertures  220   c.  Blade  210  of the particular embodiment depicted has a rectangular cutting profile. To install the blade assembly, blade coupling plate  214  is placed inside of blade  210  to nest against lip  211 . The blade and coupling plate are together placed over the platen so that studs  216  pass through the larger portions of the apertures  220  and the blade assembly is then slid so that the larger radius portions of the studs are over the smaller radius portions of apertures  220 . Fastener  218  is then placed successively through apertures  220   a  and  220   b  in order to secure the components together. Guide pins  228  pass thorough apertures  226  and  222 , which are shaped and sized to permit the platen and the coupling plate to agitate without interference from the guide pins. While apertures  226  and  222  are depicted as elongate in  FIG. 1 , or circular in  FIG. 6 , the size and shape is dependent on the particular path of the platen which varies according to the mechanical movement. While preferably coupling plate  214  is used to join blade  210  to platen  224 , flanges  223  with apertures such as that shown in ( FIG. 12   c ) may be formed in the blade for the reception of locking fasteners that couple the blade to the platen.  FIG. 2  shows the relative position of each blade assembly component.  FIG. 3  shows the inwardly formed lip  211  of blade  210 . 
         [0051]    While blade  210  is preferably continuous, it may be a single blade that is bent or formed to the desired shape or comprised of multiple joined blades by seam welds or other joining means appreciated by those having skill in the art and benefit of this disclosure. It should be noted that among the many benefits accruing to the continuous blade structure is the tendency to the continuous blade to trap dust and loose material of the cutting process and deposit the loose material within the cutting space when the cutter passes through the material to be cut. This greatly reduces any clean up required after the cutting operation. 
         [0052]      FIGS. 4 and 5  show respectively, mechanical linkage housing  230  without and with attached platen  224 . In  FIG. 5 , securing studs  220   d  are shown being threaded through apertures  220   b  of the platen and into the apertures  220   c  of the spacer guides  231 . The spacer guides are generally u-shaped assemblies having a portion of their length beneath the guide pin support plate  232  where they are loosely held. For example, the two spacer guides to the left of the housing are connected beneath support plate  232  which is connected to housing  230 . Guide pins  228  extend from support plate  232  through which offset bushing  233  passes. 
         [0053]      FIGS. 6 and 7  show respectively a top plan view of the blade coupling plate and a bottom plan view of the coupling plate showing apertures  220  and guide pin apertures  222 . 
         [0054]      FIGS. 8 and 9  show respectively, a plan view of the platen  224  showing guide pin apertures  222  and a bottom up perspective view showing a bearing recess, and apertures for the securing studs. 
         [0055]      FIG. 10  depicts a number of exemplary tooth configurations for blade  210  for the vibratory cutting of various materials and should be considered non-limiting. Other tooth profiles will suggest themselves to those having skill in the art and benefit of this disclosure. 
         [0056]      FIG. 11  is a bottom plan view of another embodiment according to the present invention, here shown with a cylindrical blade  210  for cutting circles. The blade has a lip or flanged projection (not shown) like the rectangular blade previously depicted and is attached to the platen  224  in the same way as the rectangular blade, however, with a circular blade coupling plate  214 . 
         [0057]      FIGS. 12   a  and  12   b  show blade  210  with tapered and outwardly curved cutting edges wherein kinetic energy is concentrated on a smaller region of the blade when it is initially plunged into a material. 
         [0058]    It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. For example, a dust gathering system with or without containment similar to those already used with sanding tools can be added without departing from the scope of the present invention. The addition of a light, level, depth indicator or stud locator in any combination can be added without departing from the scope of the invention. The configuration of a handle, handhold or grip for manipulating the tool can be of any design and can be for one or two-handed operation. It is also conceivable that the disclosed hole cutting system may be integrated with a robotic hole cutter. Likewise, persons having skill in the art will appreciate that modifications to OEM platens may be made to make use of particular makes and models of sheet sanders or other tools without departing from the instant invention. Accordingly, it is intended that this disclosure encompass any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments as would be appreciated by those of ordinary skill in the art having benefit of this disclosure, and falling within the spirit and scope of the following claims.