Patent Publication Number: US-2009227188-A1

Title: Vacuum Sander Having a Porous Pad

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to sanding mechanisms, and, is more particularly directed to a sander with an attached vacuum. 
     2. Description of Related Art 
     Drywall is currently the most popular material for finishing interior walls and ceilings. Drywall is typically sold in panels having predetermined dimensions. Because these dimensions do not usually correspond with the dimensions of a wall to be finished, a plurality of panels may be necessary to finish a wall. Joint compound is typically applied to the seam between two drywall panels in order to hide the seam. The joint compound is typically applied over the seam with a trowel and allowed to dry. The excess joint compound is then removed by sanding to create a smooth wall surface. Various types of sanding materials have been used for removing excess joint compound including sandpaper and screens. These materials may be employed with manual devices such as on sanding blocks or used in conjunction with automated sanding mechanisms. 
     While sanding the joint compound is obviously necessary to produce a smooth wall surface, it produces a significant amount of dust. Joint compound becomes a fine airborne dust when sanded and travels throughout the structure being finished. This dust is undesirable, especially for someone remodeling their home, because it becomes embedded in furniture, clothing and bedding, and it creates a mess in the home. Cleanup of the dust is time consuming, messy, and costly. The dust may also create or exacerbate health conditions, such as respiratory, skin and eye conditions. Further, after sanding the excess joint compound, dust remaining on the drywall must be removed before painting. 
     In an effort to control the amount of dust, automated drywall vacuum sanders have been developed utilizing a sander attached to a vacuum. One type of vacuum sander known in the art utilizes sandpaper attached to a rotating plate. A housing with a larger diameter than the plate surrounds one side of the plate such that there is a gap between the peripheral edge of the plate and the peripheral edge of the housing. A vacuum is coupled to the housing at the gap for capturing joint compound particles removed by the sander. 
     Another type of vacuum sander utilizes a sanding screen affixed to a plate having grooves. A vacuum coupled with the grooves draws removed joint compound through the screen. Yet another type of vacuum sander has a rotating plate with holes passing through the plate. A vacuum is coupled with the holes. The sander is used with sandpaper that has holes aligning with the holes in the plate. The sandpaper mounts on the plate opposite the vacuum. 
     While all of the vacuum sanders developed to date are useful, a significant amount of the particles removed by the sandpaper or screen are not captured by the vacuum because the particles are not aligned directly with the holes or gaps in the sander device and the holes constitute a small percentage of the total sanding area. In addition, the sandpaper or screen material may damage the underlying wall by creating swirls or other indentations in the wall. Lastly, it is sometimes difficult to mount the sandpaper or screen on the plate to align with the holes or gaps. Thus, a need remains in the art for an improved vacuum sander that captures a significant portion of the particles removed by the sander, avoids damage to the surface being sanded, is easy to use, and results in much less dust and consequent cleanup. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed toward a vacuum sander comprising a porous pad coupled with a face plate and a vacuum. A vacuum is coupled with at least a portion of the pad. The pad is moved over a surface to be sanded to remove particles from the surface. The vacuum is configured to suck at least a portion of the particles removed from the surface. The pad comprises a thickness sufficient to temporarily retain at least a portion of particles removed from the surface within the pad. Thus, the sander captures the vast majority of the particles removed from the surface sanded so as to substantially reduce dust relative to conventional vacuum sanders. 
     In another embodiment, the present invention is directed toward a vacuum sander comprising a porous pad removably affixed to a face plate. The pad covers one or more openings in the face plate and a vacuum is coupled with the opening on the opposite side of the face plate from the pad. The vacuum sucks particles removed from a surface to be sanded into the pad and through the opening(s) in the face plate. The pad has a thickness sufficient to temporarily retain at least a portion of the particles removed from the surface before they are sucked through the opening(s) by the vacuum. The one or more openings in the face plate preferably have a surface area of at least 1%, preferably at least 10%, of the surface area of the pad overlying the openings so as to enhance the vacuum action through the pad. 
     In a preferred embodiment, the pad comprises a core of entangled fibers with pores located between the fibers. Particles removed from the surface being sanded are temporarily retained or stored within the pores of the pad. The pad is preferably removably affixed to a face plate with hook and loop fasteners or pressure sensitive adhesive. The vacuum sucks particles retained within the pores into a receptacle. A prime mover (e.g. motor) is coupled with the face plate for moving the face plate. In the preferred embodiment, the apparatus is adapted for use in sanding excess joint compound from drywall, but the apparatus may be used to sand other materials. 
     The pad of the present invention is preferably constructed of entangled fibers which do not damage the drywall being sanded. Hook and loop fasteners or pressure sensitive adhesive preferably used to affix the pad to the faceplate facilitate the quick replacement of a worn pad. One advantage of the present invention is that the porous nature of the pad combined with the thickness of the pad creates storage capacity for removed particles. The storage capacity ensures that particles are retained within the pad until they are sucked into the attached vacuum, thus substantially reducing dust. The present invention is also directed to a method of sanding utilizing a porous abrasive pad in conjunction with a vacuum. 
     Additional aspects of the invention, together with the advantages and novel features appurtenant thereto, will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view of a sander according to the present invention shown partially in cross-section; 
         FIG. 2  is a top plan view of a pad of the sander of  FIG. 1 ; 
         FIG. 3  is a bottom plan view of a face plate of the sander of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of an alternative embodiment of a sander according to the present invention; 
         FIG. 5  is a top plan view of a pad of the sander of  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of an alternative embodiment of a sander according to the present invention; and 
         FIG. 7  is a bottom plan view of an intermediate pad of the sander of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     An apparatus in accordance with one embodiment according to the present invention is denoted generally by  10  in  FIG. 1 . Apparatus  10  is a sanding machine having a housing  12 , a motor  14 , a shaft  16 , a face plate  18 , an exhaust manifold  20 , a vacuum  22 , a receptacle  24  and a porous abrasive pad  26  removably coupled with face plate  18  for sanding material from a surface. 
       FIG. 3  shows eight openings  28  in face plate  18 . Openings  28  are in fluid flow communication with exhaust manifold  20 , as shown in  FIG. 1 . Exhaust manifold  20  is coupled with vacuum  22  outside of housing  12 . Vacuum  22  is coupled with receptacle  24 . Vacuum  22  is adapted to suck material through openings  28  and exhaust manifold  20  and deposit the material in receptacle  24 . 
     Shaft  16  couples face plate  18  with motor  14  for rotating face plate  18 . While  FIG. 1  shows the face plate coupled to a motor with a shaft, it is within the scope of the invention for the face plate to be coupled to any type of prime mover for moving the face plate, or for the face plate to be operated manually. Also, the face plate movement is not limited to rotary motion, the face plate may have any type of motion including, but not limited to, orbital, longitudinal, lateral or random motion. Further, the face plate may be adapted to vibrate. It is also within the scope of the invention for a single prime mover to drive both the face plate and the vacuum. 
       FIG. 1  shows the apparatus  10  positioned over a surface  30 , such that pad  26  is in contact with surface  30 . Particles  32  removed from surface  30  are shown within openings  28  of face plate  18  and within exhaust manifold  20 . Surface  30  preferably comprises a wall with drywall joint compound thereon, but it is within the scope of the invention for the surface to be any material needing polishing or sanding. 
       FIG. 1  shows pad  26  with a bottom surface  33 , a top surface  34 , and a side surface  36  defined by a core of entangled fibers  38 . Pores are located between the fibers for retaining dust or material removed from surface  30 . Pad  26  has a thickness or storage capacity allowing particles  32  removed from surface  30  to be stored or retained within the pores of pad  26 . This thickness also provides a cushion so as to minimize damage to the surface being sanded. Preferably, the pad has a thickness of between 1/16 inch to 3/4  inch, and more preferably a thickness of between ⅛ inch to 3/8  inch. Preferably, the entangled fibers  38  are polyamide fibers coated with an abrasive such as aluminum oxide or silicon carbide. Preferably, a binding agent binds the abrasive to the fibers. The binding agent may be phenol, epoxy, urethane, polyester, or any other suitable binder. Although a preferred construction for the porous pad is described herein, it is within the scope of the invention for the pad to be constructed from other materials so long as the pad is porous and abrasive in nature. One suitable material that may be used to construct the pad is sold under the trademark Mirlon™ by KWH Mirka Ltd., a company headquartered in Finland. 
     While pad  26  is described above as constructed from entangled fibers coated with an abrasive, the pad may have any type of construction. For example, the pad may be constructed from woven or knit fibers. Additionally, the pad may be constructed of fibers integrated into a non-woven structure by needle punching, through-air bonding, hydro entangling, spun-bonding, chemical bonding or mechanical processing. The pad may be constructed of a polymeric material, or natural or synthetic fibers. A non-exhaustive list of suitable materials for the pad include polyolefin, polyester, polypropylene, polyvinyl chloride, vinylidene chloride, nylon, polytetrafluoroethylene, polycarbonate, polyacrylate, polyoxymethylene, polystyrene, ABS, polyetherester, polyamide, polycaprolactan, thermoplastic starch, polyvinyl alcohol, polylactic acid, polyphenylsulfide, polyvinylidenes, polyurethane, polyurea, cotton and rayon. The material that the pad is constructed from may be abrasive, or additionally, the pad may be coated with an abrasive material as described above. 
     Pad  26  is removably affixed to face plate  18  with hook and loop fasteners  40  and  42 , as shown in  FIG. 1 .  FIG. 3  shows hook fasteners  40  affixed around a peripheral edge of face plate  18 . Preferably, the hook fasteners are laminated to the face plate with adhesive, but other connection means are within the scope of the invention.  FIG. 2  shows a backing  44  affixed to pad  26  adjacent the peripheral edge of the pad. Preferably, backing  44  is adhered to pad  26  with adhesive, but other connection means are within the scope of the invention. Loop fasteners  42  extend outward from backing  44 . Preferably, loop fasteners  42  are woven into backing  44 , but it is within the scope of the invention for the loop fasteners to be adhered to the backing or affixed to the backing by any other connection means. It is also within the scope of the invention for the entangled fibers to be adapted to affix directly to hook fasteners. Additionally, loop fasteners may be woven into the entangled fibers around a peripheral edge of one or both sides of the pad for removably affixing the pad to hook fasteners. It is also within the scope of the invention for the hook and loop fasteners to be switched such that the hook fasteners are affixed to the pad and the loop fasteners are affixed to the face plate. Further, it is not an essential feature of the invention that the pad and face plate are removably affixed by hook and loop fasteners, the pad and face plate could be affixed by corresponding pin and slot structures, brackets, adhesive, pressure sensitive adhesive, or any other connection means known in the art. 
     Pad  26  is affixed to face plate  18  over openings  28 , as shown in  FIG. 1 . This allows material removed from surface  30  to be sucked into porous pad  26  by vacuum  22 . Backing  44  has an opening  46  which is sized such that the opening  46  aligns with openings  28  on face plate  18  when hook and loop fasteners  40  and  42  are joined, as shown in  FIGS. 2 and 3 . In this manner, particles may move freely from the pad  26  through the openings  46  and  28 . Preferably, the total surface area of backing  44  is approximately 25 to 75% of the surface area of the total surface of pad  26 . In addition, the total surface area of openings  28  comprise at least 1% of the surface area of opening  46  and most preferably at least 10% of opening  46  so as to enhance the vacuum action through the entirety of the pad. The pad  26  of the present invention may be used with many conventional sanders that have a face plate with at least one opening and a vacuum coupled with the opening. 
     As shown in  FIG. 1 , a control circuit  46  is positioned within housing  12  for controlling the operation of the sander. Control circuit  46  receives power  48  from a remote power source, such as an electrical cable or a battery. A rheostat  50  is in electrical communication with control circuit  46  for varying the speed of motor  14 . An on/off switch  52  is also in electrical communication with control circuit  46 . Control circuit  46  provides controlled power to motor  14  in accordance with the input signals provided by rheostat  50  and on/off switch  52 . Vacuum  22  may be powered by power source  48  or by some other external power source. 
     Referring now to  FIG. 4 , an alternative embodiment of sander according to the present invention is indicated generally as  100 . Sander  100  comprises a housing  102 , a shaft  104  extending through an opening  106  in the housing, a face plate  108  joined with the shaft, an intermediate pad  110  coupled to the shaft, a porous pad  112  affixed to the intermediate pad, and a vacuum (not shown) coupled with an opening  114  in the housing via a hose  116 . Housing  102  has a bottom surface  130  with a recess  132  formed into the bottom surface to receive face plate  108  and intermediate pad  110 . An inner wall  134  extends upward from bottom surface  130  and surrounds recess  132 . Inner wall  134  has a diameter that is slightly larger than the diameter of either the face plate  108  or the intermediate pad  110 , thus forming a gap between the inner wall  134  and the peripheral edges of the face plate and intermediate pad. This gap is in fluid communication with second opening  114  and the vacuum joined therewith by hose  116 . 
     A retainer  118  extends outward from shaft  104  for joining face plate  108  with the shaft. Face plate  108  has an opening  120  for receiving shaft  104 . A slot in retainer  118  receives a portion of face plate  108  surrounding opening  120 . The structure joining face plate  108  to shaft  104  is not essential to the invention and thus it is within the scope of the invention for the face plate to be joined with the shaft by any means known in the art. 
     Intermediate pad  110  has an inner opening  122  for receiving shaft  104 . A nut  124  has threads that engage with threads on shaft  104 . A washer  126  positioned between the nut  124  and pad  110  engages a portion of pad  110  surrounding opening  122  and presses the pad against face plate  108  when the nut is tightened on the shaft. Face plate  108  also preferably comprises an abrasive surface that engages the top surface of intermediate pad  110  for coupling the pad with the face plate and shaft. It is within the scope of the invention for the intermediate pad to be coupled with the face plate and shaft by any suitable method known in the art including hook and loop fasteners and pressure sensitive adhesive. The intermediate pad is preferably constructed from a compressible and resilient polymeric material, although it is within the scope of the invention to construct the intermediate pad from any material. 
     Intermediate pad  110  and porous pad  112  are preferably joined with adhesive, although it is within the scope of the invention for the pads to be joined by any means known in the art including hook and loop fasteners. The pads  110  and  112  may be joined using any of the methods described above to join face plate  18  and pad  26 , shown in  FIG. 1 . Porous pad  112  extends below bottom surface  130  of housing  102  and is constructed from a material capable of sanding a surface. The porous pad  112  is preferably constructed from any of the materials described above for pad  26 , shown in  FIGS. 1 and 2 . The porous pad  112  also preferably has a thickness that is sufficient to temporarily retain at least a portion of particles removed from a surface sanded by the pad, as described above in connection with sander  10  shown in  FIG. 1 . 
     As shown in  FIG. 5 , intermediate pad  110  has six wedge shaped openings  128   a - f  spaced around a peripheral edge of the pad such that the peripheral edge is discontinuous. As shown in  FIG. 4 , the face plate  108  and intermediate pad  110  are received by recess  132  in housing  102 , and there is a gap between inner wall  134  and the peripheral edges of the face plate and intermediate pad. The vacuum coupled with hose  116  sucks at least a portion of particles removed from a surface being sanded either through or around pad  112 . Particles sucked through porous pad  112  pass through one of the openings  128   a - f  in intermediate pad  110 , through the gap between inner wall  134  and face plate  108 , and then through opening  114 . Particles passing around pad  112  are sucked through the gap between inner wall  134  and face plate  108  and then through opening  114 . 
     Housing  102  is preferably pivotally joined to one end of an elongate tube (not shown), and a motor (not shown) for rotating shaft  104  is preferably joined to the other end of the tube. Sander  100  also preferably has a power supply, on/off switch and speed control as described above for sander  10  shown in  FIG. 1 . The motor and shaft of sander  100  preferably rotate face plate  108  and pad  112 , however it is within the scope of the invention for the face plate and pad to move in any of the manners described above for face plate  18  and pad  26 , shown in  FIG. 1 . 
     Referring now to  FIG. 6 , an alternative embodiment of sander according to the present invention is indicated generally as  200 . Sander  200  is substantially similar to sander  100 , shown in  FIG. 4 , except that there is no opening in the center of porous pad  202 , and porous pad  202  is removably affixed to intermediate pad  204  with hook and loop fasteners  206  and  208 . Hook fasteners  206  joined to the bottom of intermediate pad  204 , shown in  FIG. 7 , engage with loop fasteners  208  joined to the top of porous pad  202 . It is within the scope of the invention for the hook and loop fasteners to be interchanged, for the porous pad  202  to be joined with the intermediate pad  204  with pressure sensitive adhesive, or for the pads to be joined using any of the other methods described above in connection with sanders  10  and  100 . 
     In use, pad  26  of sander  10 , shown in  FIGS. 1-3 , is positioned over face plate  18  and loop material  42  is engaged with hook material  40 . Thus, entangled fibers  38  of pad  26  cover the openings  28  in face plate  18 . The sander is connected to a power source  48  and the on/off switch  52  is switched to the on position. Vacuum  22  is also turned on via a connection with power source  48  or another external power source. The desired speed of motor  14  is adjusted with rheostat  50 . Motor  14  rotates shaft  16 , face plate  18  and pad  26 . Rotating pad  26  is positioned against a surface  30  to be sanded. The abrasive material on pad  26  removes particles  32  from surface  30 . Vacuum  22  sucks particles  32  removed from the surface  30  into pad  26  where the particles are temporarily stored or retained within the pad&#39;s pores. Vacuum  22  sucks the particles  32  retained within the pores of pad  26  through the openings  28  in face plate  18  and through exhaust manifold  20 . The particles are finally deposited in receptacle  24 . 
     In use, pad  110  of sander  100 , shown in  FIGS. 4 and 5 , is positioned over face plate  108  such that opening  122  receives shaft  104 . Then, washer  126  is positioned over pad  110  and nut  124  is screwed on shaft  104  compressing pad  110  against face plate  108 . The sander is then connected to a power source and the motor (not shown) is turned on. The motor rotates shaft  104 , face plate  108 , intermediate pad  110  and porous pad  112 . Rotating pad  112  is positioned against a surface to be sanded. The abrasive material on pad  112  removes particles from the surface. The vacuum (not shown) coupled to hose  116  sucks at least a portion of the particles removed from the surface either through or around pad  112 . Particles sucked through pad  112  pass through one of openings  128   a - f  in pad  110 , shown in  FIG. 5 , through the gap between inner wall  134  and face plate  108 , and through opening  114 . Particles sucked around pad  112  pass through the gap between inner wall  134  and face plate  108  and through opening  114 . Pad  112  also temporarily retains at least a portion of the particles removed from the surface. These particles are preferably sucked through pad  112  by the vacuum. 
     Sander  200 , shown in  FIGS. 6 and 7 , operates in the same manner as sander  100  described above except that pad  202  may be detached from intermediate pad  204  using hook and loop fasteners  206  and  208 . This allows a user to change porous pad  202  without unscrewing the nut pressing the intermediate pad against the face plate. 
     The sanders described above eliminate the airborne dust created when sanding drywall joint compound because they capture virtually all removed particles and deposit them in a receptacle. The storage capacity of the pads ensure that virtually no removed particles become airborne before they are sucked into the receptacle. The entangled fibers of the pads also do not damage the drywall or create undesirable swirls in the drywall. 
     From the foregoing it will be seen that this invention is one well adapted to attain all ends and objectives herein-above set forth, together with the other advantages which are obvious and which are inherent to the invention. 
     Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative, and not in a limiting sense. 
     While specific embodiments have been shown and discussed, various modifications may of course be made, and the invention is not limited to the specific forms or arrangement of parts and steps described herein, except insofar as such limitations are included in the following claims. Further, it will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.