Abstract:
A dust shroud for rotary tools includes a front half and a back half which are attachable together along an axis thereof to form a dust shroud. The dust shroud is mountable to a rotary power tool after mounting a mandrel in the power tool, and includes one or more openings to allow a person to lock the shaft of the tool while the dust shroud is mounted thereto to allow a person to change a worn out abrasive pad. The dust shroud is particularly suited for use with die grinders and similar rotary tools.

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Application Ser. No. 61/021,323, filed Jan. 15, 2008, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention relates to dust shrouds. More specifically, the present invention relates to a dust shroud for rotary tools such as die grinders. 
     2. State of the Art 
     Dust shrouds have become more commonly used for many reasons. Die grinders, for example, are commonly used for grinding, paint removal, and other tasks. Without a dust shroud, debris is scattered over a wide area. It is desirable to contain the dust which is created for several reasons. It is desirable to contain the dust and debris to keep the workplace cleaner and to minimize the time necessary to clean up afterwards. Fine dust is often created which can be quite difficult to clean up afterwards. It is also desirable to contain the dust and debris to keep the same from getting into the tool itself, causing premature failure of the bearings, motor, etc. Additionally, debris such as paint dust poses a health risk to the machine operator and others who may breathe it. It is desirable to collect the dust to minimize any exposure. 
     Right angle die grinders are often used to remove paint from airplanes and other objects. In such a situation, it is not desirable that the paint debris is spread over the airplane as it may require extensive cleanup. Airplane paint often contains metals such as chromium and cadmium for corrosion protection. Workers may use a die grinder to remove paint from the airplane to service the airplane, repaint the airplane, etc. It is desirable to collect all of the paint which is removed to avoid environmental contamination or damage to the worker&#39;s health. 
     Paint removal with a die grinder typically involves the use of a mandrel with a backing pad that is mounted in the die grinder and an abrasive disk that is mounted to the backing pad. Commonly used abrasive disks require a half turn to lock the disk into the backing pad. One difficulty in providing dust shrouds for rotary tools is that the dust shroud will likely cover the collet and nut used to hold the mandrel and backing pad into the die grinder. Thus, the mandrel and backing pad are not easily installed after the shroud is in place. The shroud, however, ideally extends around the back of the backing pad and would be difficult to install if the mandrel and backing pad are mounted to the die grinder. Additionally, it is difficult to remove and attach the abrasive disks if a dust shroud is covering the collet, nut, and backing pad. Abrasive disks are typically replaced frequently during use as they wear. 
     The lack of an available dust shroud for rotary tools has resulted in workers being exposed to hazardous materials, or in companies having to create a large dust-sealed environment for performing work. Both of these situations are undesirable as they result in either increased cost or increased exposure to hazardous chemicals. 
     There is thus a need for a dust shroud for a die grinder or similar rotary tools. There is a need for a dust shroud which may be mounted easily to the tool after a mandrel has already been mounted to the tool, and which allows for easy replacement of abrasive disks. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved dust shroud for rotary tools such as die grinders. 
     According to one aspect of the invention, a dust shroud is provided which is split into two halves and which is assembled in place on the rotary tool. This allows the dust shroud to be placed on the tool after a mandrel or backing pad has been attached to the tool. 
     According to another aspect of the invention, the dust shroud allows some access to the collet or collet nut to allow a user to lock the shaft of the tool to facilitate attachment or removal of an abrasive disk from a mandrel. 
     These and other aspects of the present invention are realized in a universal dust shield as shown and described in the following figures and related description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the present invention are shown and described in reference to the numbered drawings wherein: 
         FIG. 1  shows a side view of a prior art right angle die grinder; 
         FIG. 2  shows a perspective view of the front half of a dust shroud of the present invention; 
         FIG. 3  shows a perspective view of the back half of the dust shroud of  FIG. 2 ; 
         FIG. 4  shows a side view of the dust shroud of  FIG. 1  mounted to a tool; and 
         FIG. 5  shows another side view of the dust shroud of  FIG. 1  mounted to a tool. 
     
    
    
     It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The embodiments shown accomplish various aspects and objects of the invention. It is appreciated that it is not possible to clearly show each element and aspect of the invention in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the invention in greater clarity. Similarly, not every embodiment need accomplish all advantages of the present invention. 
     DETAILED DESCRIPTION 
     The invention and accompanying drawings will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawings and descriptions are exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims. 
     Turning now to  FIG. 1 , a side view of a prior art right angle die grinder  10  is shown. The die grinder  10  typically includes a body  14  which houses an air turbine (not shown), an air inlet  18 , a handle  22  for controlling the tool, a right angle gearbox  26 , an output shaft  30 , a collet  34 , and a collet nut  38 . The collet  34  and collet nut  38  are tightened with wrenches to mount a cutting or abrasive bit in the collet  34 . The die grinder  10  rotates the cutting bit. A common use for die grinders  10  is to remove paint or otherwise clean or dress a surface. To perform this task, a mandrel  42  with a backing pad  46  is commonly used. The mandrel  42  is mounted into the collet  34  by tightening the collet nut  38 . 
     An abrasive pad  50  is mounted to the backing pad  46  via a mounting post  54  with a coarse screw thread  58 . The backing pad  46  has a corresponding receptacle. The abrasive pad  50  and backing pad  46  are designed to allow the abrasive pad to be easily mounted without tools. A user simply twists the abrasive pad  50  relative to the backing pad  46  with their hands. The user needs sufficient access to either hold the backing pad  46  or lock the shaft  30  to do so. 
     Turning now to  FIGS. 2 ,  3 ,  4 , and  5 , a dust shroud for rotary tools according to the present invention is shown.  FIGS. 2 and 3  show perspective views of the front and back of the shroud, and  FIGS. 4 and 5  show the shroud mounted to a die grinder. As has been discussed, many uses of the die grinder  10  are for removing paint or otherwise preparing a surface. This type of work often generates debris which is hazardous. The dust shroud  100  is designed for use with an abrasive pad  50  and mandrel  42  as shown. The dust shroud  100  is shown for use with a right angle die grinder  10 , but it will be appreciated that it may also be used with a straight die grinder by modifying the top of the shroud to exit straight instead of at a right angle. 
     The dust shroud  100  includes a front half  104  and a back half  108  which attach together. The shroud halves  104 ,  108  include tabs  112  which have holes  116  or threaded inserts  120  which receive bolts to connect the halves together. The front half  104  of the shroud includes flanges  122  which receive a portion of the back half  108  of the shroud to make the shroud  100  stronger and more secure during use. The upper body portion  124  of the shroud halves  104 ,  108  is shaped to fit snugly around the die grinder  10  to hold the shroud  100  in place. The shroud  100  includes an enlarged portion  128  which extends around the backing pad  46  and abrasive pad  50 . The enlarged portion  128  includes a horizontally extending top  132  and a skirt  136 . 
     As is seen, the back half  108  of the shroud  100  has an angled upper portion  110  which extends backwards at a right angle to the axis of the die grinder collet  34  and abrasive pad  50 . The angled upper portion  110  extends along the handle portion of a right angle die grinder to help secure and stabilize the dust shroud  100 . The dust shroud  100  is particularly used with a right angle die grinder since this die grinder is commonly used in applications which may generate hazardous dust, such as removing paint, and because such a dust shroud has been unavailable for such a die grinder. 
     As shown in  FIG. 4 , the skirt  136  may be tapered so as to be shorter at the front of the die grinder  10  and longer at the back of the die grinder. This allows a user to more easily use the abrasive pad  50  and die grinder  10 , and promotes the proper positioning of the die grinder during use to allow the debris to be collected by a vacuum port  140 . The vacuum port  140  is open to the enlarged portion  128  of the dust shroud  100  via opening  142  and connected to a vacuum so as to draw air from around the abrasive pad  50 . 
     It will be appreciated in viewing the shroud  100  that it is difficult to mount a mandrel  42  with backing pad  46  in the collet  34  after a shroud is installed on the die grinder  10 . This is because the die grinder obstructs access to the collet  34  and collet nut  38 . The shroud  100  thus includes a front half  104  and back half  108  which may be assembled to the die grinder  10  after mounting the mandrel  42  in the collet  34 . The shroud  100  provides a design which is easy to install on a die grinder or other similar tool after mounting a mandrel  42  in the collet  34  while still providing a shroud which is strong and not easily broken during use. 
     It is generally not problematic to require removal of the shroud  100  in order to remove the mandrel  42  and backing pad  46 , as the mandrel is not frequently changed while a person is using the die grinder  10 . As has been discussed, however, the abrasive pad  50  is changed frequently during use as the abrasive wears out. It is thus desirable to be able to change the abrasive pad  50  without removal of the shroud  100 , thus promoting worker compliance in using the shroud. If a worker had to remove the shroud  100  in order to change the abrasive pad  50 , many workers would simply leave the shroud off of the die grinder and not use the shroud. 
     The front half  104  of the shroud  100  is provided with holes  144  which allow a thin wrench to be inserted to engage the collet  34  or collet nut  38 . The holes  144  could also be provided in the back half  108  of the shroud  100  if desired.  FIG. 5  shows another side view of the shroud  100  and die grinder  10 . The die grinder  10  and mandrel  42  are visible, but not all structures are numbered for clarity. A thin and elongate wrench  148  may be inserted through the holes  144  to engage the collet  34  or collet nut  38 , as shown at  148   a . The holes  144  allow the wrench  148  to be used to lock the shaft  30  and facilitate removal of the abrasive pad  50 . 
     While the abrasive pad  50  is relatively easy to remove by hand, it can not be removed if the shaft  30  is freely spinning. The holes  144  and wrench  148  are beneficial as they provide a safe way to lock the shaft  30  and replace the abrasive pad  50 . Without a convenient way to lock the shaft  30 , a user may choose to not use the shroud  100 , or may try to push a finger or other object between the backing pad  46  and shroud skirt  136  to lock the shaft  30 . Both of these situations results in increased safety risks to the user. 
     There is thus disclosed an improved dust shroud for rotary tools. It will be appreciated that numerous changes may be made to the present invention without departing from the scope of the claims.