Patent Publication Number: US-2006019585-A1

Title: Device for circular grinding, sanding and stripping tools to attach to any power drive

Description:
BACKGROUND AND OBJECT OF THE INVENTION  
      There are many power sanding, grinding and stripping tools used for removing paint and other coatings from wood, fiberglass, steel, and resin surfaces. These tools are designed with cutting head and motor drive as a single unit. The present invention is designed to mount any one of these various cutting tool onto the same power source.  
      The present invention allows the purchase of one power drive or source and allows the purchase of multiple tool accessories that will mount on that power drive.  
      In the invention presented herein, stripping is accomplished by a bar style blade holder having stripping elements capable of stripping two adjacent 90 degree surfaces simultaneously. This is analogous to the stripping action described in the copending patent application Ser. No. 10/671920 in the names of the same inventors named herein. This tool requires a special type of rigid guard housing that also doubles as a dust collector. Because of the specialized type of guard housing, it is necessary to be able to remove the cutting action of the tool with the guard housing and the invention allows the user the ability to do so.  
      There are many rotary-resurfacing tools on the market. All of these are permanently mounted and are unable to be interchanged with spindle type power drives. All of these tools could be interchangeable with spindle type power drives with this invention. One advantage of this device is that since the tool head is not fixed to the body of the motor, it can move in relation to the power drive. Thus, for some applications, the operator can adjust the position of the head and motor body to fit into tight places.  
      There are many prior art rotary-resurfacing tools on the market, but they are cumbersome to handle and are unable to clean coatings from areas next to windows, doorframes, and corner boards. Some examples are discussed below.  
      U.S. Pat. No. 4,544,957, issued to Zayat, describes a rotary resurfacing tool capable of simultaneously resurfacing two surfaces with a rotary disc. The tool is designed to simultaneously to remove a coating from the horizontal surface of a clapboard and the underside butt end of the adjacent clapboard. The mounting assembly for the rotary disk is permanently attached to a power drive.  
      U.S. Pat. No. 5,609,516, issued to Courson, describes a power tool with abrasive sheets enclosed by a circular shroud covering. The shroud covers the abrasive sheets allowing the collection of dust by a vacuum system. While it appears that this device can be mounted on a spindle shaft, it must be noted that the device does not need a housing to adjust the depth of a cutting edge.  
      U.S. Pat. No. 5,791,979 describes a vacuum shroud covering a grinding tool. The flexible bonnet surrounding the grinding disc allows for the collection of stripped debris into a vacuum. While the drive shaft is mounted to the motor by means of a chuck, the flexible bonnet is attached to the motor drive by four machine screws, which do not allow for easy removal.  
      U.S. Pat. No. 6,027,399, issued to Stewart, describes a grinding tool accessory shroud for containing and removing dust into a vacuum. The grinding tool accessory has flexible bristles with two chambers, the inner chamber collects the dust and the outer chamber flexes for contoured portions of a work surface. The arrangement of this tool is like that of Duncan, where a chuck attaches to the drive shaft and the bonnet is attached by machine screws to the motor drive.  
      U.S. Pat. No. 4,765,099, issued to Tanner, describes a sanding and dust collecting apparatus that consists of a flexible curtain for containment of dust around a sanding disc. The curtain is hard mounted to the power drive.  
      U.S. Pat. No. 6,148,880, issued to Dehde et al., describes a flat surface-milling machine with two or more cutters, but no removal system is provided and the machine only grinds one surface at a time. This also is a permanently mounted system and is not suited to an adapter of the type disclosed herein.  
      U.S. Pat. Nos. 4,337,811; 3,731,338; and 6,190,099, issued to Partington, Walsh and Schultze, respectively, all describe circular rotary planers or grinders with no ability to simultaneously grind two surfaces and no dust removal system. All these systems are permanently mounted.  
      U.S. Pat. No. 6,491,575, issued to Sarantits, describes a rotary tool with replaceable blades that can resurface two surfaces simultaneously, a semi rigid guard and a dust collecting system. The cutting depth of the horizontal work surface is set by ball bearings and the dust collection system is a shroud surrounding the entire work surface. The semi rigid guard is permanently mounted to the power drive.  
      U.S. Pat. No. 5,520,076, issued to Junkers, describes a threaded connector for a power tool having a threaded spindle. The arrangement includes a one piece metal device with a female threaded connector end and a hexagonal socket end. It does not allow for the depth control needed for a power cutting, grinding or sanding tool.  
      U.S. Pat. No. 5,586,847, issued to Mattern, describes a power tool adapter for a motorized screw driver. A metal sleeve that fits over the hexagonal screw driver bit holds a drill bit. This allows for the drill bit to be easily removed. An operator can pre-drill starter holes for screws and easily remove the drill bit, exposing the screw driver head for inserting screws.  
     BRIEF SUMMARY OF THE INVENTION  
      The invention is generally directed to resurfacing tools having various circular sanding, grinding and stripping devices adapted to be coupled to a drive shaft and that require the use of a rigid guard housing for protection of the operator of the tool. A mounting assembly is provided to support the housing from the drive shaft a fixed distance from the resurfacing devices while allowing the drive shaft to rotate freely relative to the housing. Concurrently, the resurfacing devices are rotated by the drive shaft. The above is accomplished in part by a mounting shaft having one end attached to the drive shaft and the other end attached to the resurfacing devices and a bearing for permitting the mounting shaft to rotate freely with respect to the housing. The mounting arrangement also includes adjusting means to change the angle of the housing relative to the axis of the drive shaft so that the exposure of the resurfacing elements to the work surface is adjustable.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The drawings show the best mode of the invention as presently contemplated wherein:  
       FIG. 1A  is an axial view of the threaded mounting shaft;  
       FIG. 1B  is a cross sectional view of the mounting shaft along the lines  1 B in  FIG. 1A ;  
       FIG. 2  is an exploded side elevation view of the mounting assembly of the invention;  
       FIG. 3A  is a side elevation view similar to  FIG. 2  with the blade holder omitted; and  
       FIG. 3A  is a bottom view of the assembled resurfacing tool showing details of the blade holder.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      As best seen in  FIGS. 2-4 , the paint/coating stripping tool  2  of the invention is seen to comprise a power unit  40  which drives a drive shaft  50 . The drive shaft  50  is intended to be coupled to a bar style holder  24  which has mounted thereon two cutting blades  26  held in place by two blade screws  16 ,  FIGS. 2 and 3 A,  
      A mounting shaft  8  attaches to the threaded shaft  5  on one end  8   a  and to the blade holder  24  on the other end  8   c.  The shaft  8  has a tapped threaded cylindrical opening starting near the end  8   a  of the mounting shaft and continuing nearly the entire length thereof, this threaded opening receiving the threaded drive shaft  50 . The other end  8   c  of the shaft  8  is closed by an end wall  8   f  and has a notch or channel  8   d  (seen best in  FIGS. 1B, 3  and  3 A) formed therein for receiving the blade holder  24 . The end  8   c  is also provided with tapped holes  8   e  for receiving screws  16  to hold the blade holder securely in notch  8   d.    
      A rigid guard/dust collector  22  is attached to a bearing block  12  with two rigid dust collector screws  18  which maintain a set distance between the rigid guard/dust collector  22  and the bearing block  12  with two rigid dust collector spacers  28  through which the rigid dust collector screws  18  pass. The rigid guard/dust collector  22  is used to adjust the exposure of the cutting blades  26  to the work surface. This adjustment is made by the face cutting screw  34  and lock nut  34 A. The angle of the rigid guard/dust collector to the cutting blades is changed by rotating the face cutting screw  34  which moves the rigid guard/dust collector  22  up and down relative to the bearing block  12  with the pivot point at an imaginary line between the two dust collector screws  18 . A screw  32 ,  FIGS. 2-4 , is mounted on the housing  22  and extends generally perpendicular to the drive shaft  50 .  
       FIG. 3  shows the exploded view of the best mode of the tool  2  of the invention including a bar style holder which operates as the resurfacing and stripping device portion of the tool. The mounting shaft  8  extends through the rigid guard/dust collector  22  through two bearing rings  13 , is seated in the bearing block  12  and is secured in this position with the snap ring  10  around the threaded mounting shaft indent  8   b.    
      The bearing block  12  serves as an attachment point for the handle assembly consisting of the handle grip  4 , the handle extension  6  and handle screw  20 . The rigid guard/dust collector  22  is attached to the bearing block with two rigid dust collector screws  18  and two rigid dust collector spacers  28 . The rigid guard/dust collector  22  also is the attachment port for the hose connector  37 .  
      The threaded mounting shaft  8  has these distinct features: an indent space  8   b  for attaching the snap ring  10  and the threaded end  8   a  (see  FIG. 1B  for  8   a ) for attaching to the drive shaft  50  of the power source.  FIG. 2  shows the adapter end  8   c  where the mounting shaft attaches to a bar style blade holder  24  of the paint/coating stripping device  2 . The blade holder  24  is attached to the mounting shaft  8  by means of two screws  16 ,  FIG. 2 , and has two cutting blades  26  held in place with two blade screws  14 .