Abstract:
This invention is a pneumatically driven dry wall sander with the capability to create a vacuum to trap the dust, which is produced during the sanding operation, and then safely eject the dust away from the work site. A pneumatic motor that is operated by air will operate the sander and sanding disk and at the same time operate a set of impellers that create a slight vacuum. The air flow can be regulated so that the speed of the motor can be controlled depending on the specific need of the worker in performing sanding operations.

Description:
BACKGROUND OF THE INVENTION 
   A. Field of the Invention 
   This device will be used in the construction trades and specifically when sanding a wall. Sanding the walls is necessary in the construction of new homes particularly prior to the application of paint on the interior walls and ceiling. In the past, electrical sanders have been used. Because of the amount of dust that is inevitably and unavoidably produced during the sanding process, electrical equipment wears out quickly because of the exposure to high levels of contaminants that enter into the electrical equipment. 
   B. Prior Art 
   There are many other references in the prior art related to dry wall sanders. A representative example is Conboy, U.S. Pat. No. 6,468,141. Another example is Loveless, U.S. Pat. No. 6,860,799. The Conboy device is a dry wall sander, which is operated using an electrical motor. The Loveless device is a vacuum-driven sander. 
   Neither of the above referenced devices operate using a pneumatic motor nor do either of the prior patent have a vacuum system to remove the dust that is produced. 
   Another example in the prior art related to dry wall sanders is Matechuk, U.S. Pat. No. 4,782,632. This device is a dry wall sander using an electrical motor with a vacuum system. It does not however combine the vacuum system with a pneumatic motor as this device. Additionally the combination is not made obvious in Matechuk. 
   BRIEF SUMMARY OF THE INVENTION 
   This is a pneumatically operated dry wall sander. It has the advantage of not requiring an electrical current or any electrical parts. This use of pneumatics saves a great deal of money and time during the sanding operation and saves time and money during the initial set up at the site. 
   Extensive electrical cords are not needed and there is never any danger of not being able to access power at the construction site. A compressor is needed to operate this sander but the power source for the compressor is usually a small engine, which is part of the compressor. 
   During the sanding process, it is very common to have dust and other items impact all parts of the drywall sanding equipment including the operator of the equipment. Unfortunately, the effect of an excessive amount of dust on electrical equipment is to shorten the useful life of the electrical tool, including a drywall sander. Dust will collect on the armature of the electrical motor, the brushes of the electrical motor and short its life expectancy. 
   Additionally, the dust will also impact the user of the device and result in greatly reduced productivity as well as general skin irritation and other possible health hazards. As the dust is literally flying the dust will cake on the user and the user will be forced to take multiple breaks to clean his or her eyes. Safety goggles are not useful to combat this problem because the dust simply accumulates on the goggles. This results in frequent breaks and a great deal of down time with a resultant loss of productivity. 
   Additionally the inhalation of drywall dust may be associated with health problems and the vacuum system in this device would greatly reduce the possibility of health problems for the workers. 
   It is an object of this device to have a pneumatically operated dry wall sander, which would remove the necessity of having a source of electrical current while at the same time vacuuming the dust that is produced in the sanding process and distributing the dust to a remote location. 
   It is a further object to make a device, which is safer for the user in terms of general productivity as well as health issues. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of the device from the handle to the motor. 
       FIG. 2  is an exploded view of the pneumatic sander. 
       FIG. 3  is an exploded view of the drive assembly of the sander. 
   

   REFERENCE NUMBERS 
   
     
       
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
                1 
               Air fitting 
             
             
                 
                2 
               Pneumatic air motor 
             
             
                 
                2A 
               Motor collar 
             
             
                 
                2B 
               Means to mount motor collar to motor 
             
             
                 
                3 
               Pivot pin 
             
             
                 
                3A 
               Holes on Collar 
             
             
                 
                4 
               Gimbal mount housing 
             
             
                 
                5 
               Dust exhaust port 
             
             
                 
                6 
               Impeller housing 
             
             
                 
                6A 
               Impeller opening 
             
             
                 
                7 
               Brushes 
             
             
                 
                8 
               Impeller bearing 
             
             
                 
                9 
               Impeller 
             
             
                 
               10 
               Central drive shaft 
             
             
                 
               10E 
               External drive shaft 
             
             
                 
               11 
               Cotter pin 
             
             
                 
               11A 
               Cotter pin keyway 
             
             
                 
               12U 
               Upper horizontal drive gear 
             
             
                 
               12L 
               Lower horizontal drive gear 
             
             
                 
               13 
               Retaining clip 
             
             
                 
               15 
               Gear Housing 
             
             
                 
               15A 
               Second housing plate 
             
             
                 
               15B 
               Mounting means for gear housing 
             
             
                 
               16 
               Bearing 
             
             
                 
               17 
               Sanding disc 
             
             
                 
               18 
               Washer 
             
             
                 
               19 
               Disc bolt 
             
             
                 
               25 
               Device 
             
             
                 
               30 
               Air supply line 
             
             
                 
               36A 
               Air supply line at motor 
             
             
                 
               31 
               Mounting plate 
             
             
                 
               31A 
               Holes in mounting plate 
             
             
                 
               31B 
               Impeller Mounting Hole 
             
             
                 
               32 
               Dust Portal 
             
             
                 
               32A 
               Dust tubing 
             
             
                 
               33 
               Stationary gear 
             
             
                 
               35 
               Handle 
             
             
                 
               35A 
               Extension section 
             
             
                 
               35C 
               Means to connect extension 
             
             
                 
               40 
               Air adjustment 
             
             
                 
               45 
               Pressure Gauge 
             
             
                 
               50 
               Sander Assembly 
             
             
                 
                 
             
           
        
       
     
   
   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   This device  25  is a pneumatically operated sander with the added feature of vacuuming the dust that is generated during the sanding process. Pneumatic tools, in general, are common in the prior art as well as pneumatic sanders. However, in addition to performing the sanding functions the device will also create a slight vacuum that will capture the dust and discard it without interfering with the operation of the sander. 
   The sander assembly  50  is attached to a handle  35  that allows the person to maneuver the sander while on the wall to be sanded. Within the handle  35  will be flexible tubing to supply  30  air to the sander and flexible tubing to exhaust  32  the dust. Both the air supply and the exhaust port will be attached to respective portions of the casing. 
   Extension members  35 E may be connected to the handle  35  and used with this device to extend the length of the device. A means to connect the sections  35 C is also provided. Air supply tubing  30  will be placed in the interior of the extension member to allow the flow of air through the extension member to air supply tubing  36 A located at the sander and through the air fitting  1  attached to the pneumatic motor  2 . Similarly dust exhaust tubing  32 A, which mates with a dust exhaust port  5  on the sander  50  allows the dust to be ejected through the exhaust port  32 . 
   The extension members  35  will likely be hollow plastic pieces that allow the air to be supplied to the pneumatic motor and allow the dust to be expelled from the device. 
   The air fitting  1  will direct the air into the pneumatic motor  2 . The pneumatic motor  2  is powered by a source of compressed air that will be produced by an air compressor (not depicted). Air compressors are common in the prior art and are frequently used to operate pneumatic tools. 
   In order for the operator to vary the speed of the pneumatic motor a means to adjust the air flow  40  will be included. This may include a throttle valve or butterfly valve although there are many ways to adjust the flow of air into a device. Additionally a pressure gauge  45  will also be included to allow the operator to monitor the operation of the sander in this fashion. 
   The motor  2  will rest on a collar  2 A that is secured to a gimbal mount housing  4  that will allow the motor to tilt and swivel depending of the contours of the surface that is being sanded so as to properly position the sanding disk  17  on the wall to be sanded. Holes  3 A on the collar  2 A and the gimbal mount housing  4  allow pivot pins  3  to be placed through openings in the gimbal mount housing  4  to secure the gimbal mount housing  4  to the collar  2 A. A means to secure  2 B the collar  2 A to the pneumatic motor will also be provided. This means to secure is probably a plurality of bolts. 
   At one end of the pneumatic motor will be a central drive shaft  10 . The central drive shaft  10  will extend from one end of the motor to the sanding disc  17  and will rotate at the same speed as the motor. 
   The central drive shaft  10  will pass through an opening  6 A on the top of the impeller blade assembly  9  and through the opening in the bearing  8  that is in the center of an impeller blade assembly  9 . 
   An external drive shaft  10 E will be attached at one end to the bearing  8  in the center of the impeller and the central drive shaft  10  will pass through the center of the eternal drive shaft  10 E. One end of the external drive shaft  10 E will be connected to the impeller bearing and the other will secure the upper horizontal drive gear  12 U. 
   The impeller blade assembly will be circular and will contain a series of impeller vanes of predetermined shape. The impeller blade assembly  9 , when the device is assembled will be covered by the impeller housing  6 , which is larger in diameter than the impeller blade assembly  9 . 
   A mounting plate  31  will be secured to a portion of the impeller housing  6  and will partially cover the impeller blade assembly. The mounting will have a predetermined shape but will have open spaces on a portion of the plate in order to promote a flow of air through the impeller blades. Holes in the mounting plate  31 A will allow the means to mount, probably a screw (not depicted) to secure the mounting plate to the impeller assembly through the use of impeller mounting holes  31 B. 
   When the device is assembled the impeller ring  9  will be positioned in the interior of the impeller housing  6  and covered partially by the mounting plate  31  but sufficient space will be provided so that the impeller will be allowed to rotate freely. The means to secure the mounting plate will likely be a series of screws or bolts. 
   A gear housing  15  will be mounted to the mounting plate  31 . The purpose of the gear housing is to protect the internal gear mechanism from dust and other contaminants. Attached to the one surface of the interior of the gear housing  15  is a stationary gear  33 . Two gears, an upper horizontal gear  12 U and a lower horizontal gear  12 L will mate with the teeth of the stationary gear  33  inside the gear housing. The gears are designed to rotate and stay in contact during the operation of this device. 
   The upper horizontal gear  12 U will be secured to an external drive shaft  10 E that extends from the impeller bearing to the upper horizontal gear  12 U and surrounds the central drive shaft  10 . One end of the external drive shaft will have a key hole insert  11 A into which a key  11  will be inserted. The key  11  will secure the external drive shaft  10 E to the lower horizontal drive gear  12 L, which will have a key slot into which a portion of the key will be inserted. 
   The lower horizontal gear  12 L will rotate at the same speed as the motor and will mate with the stationary gear  33  on the inside of the gear housing  15 . As this lower gear  12 L rotates it will rotate the stationary gear  33  that is connected to the upper horizontal gear  12 U that in turn will rotate the upper horizontal gear  12 U in the opposite direction from the rotation of the sander disc because of the placement of the gears. 
   The lower horizontal gear  12 L is attached to a portion of the central drive shaft  10  and external drive shaft  10 E by the key. One end of the external drive shaft  10 E is connected to the impeller ring and as the lower horizontal gear turns, it will cause the impeller ring  9  to rotate in the opposite direction from the rotation of the sanding disc that is attached to the central drive shaft  10 . 
   In order to insure that the relative positions of the gears are maintained within the housing, one or more retaining pins or clips  13  may be used. In order to protect the gears from contamination a second housing plate  15 A is provided; a lubricant may also be provided within the gear housing to protect the gears. When it is assembled the gear housing will be mounted to one side of the mounting plate  31  and will be enclosed by the second housing plate  15 A. A means to secure  15 B the second housing plate  15 A to the gear housing and the mounting plate will be provided; it is anticipated that a plurality of bolts or screws are used to secure the housing. 
   The rotation of the impeller ring  9  will create a slight vacuum within the impeller housing and will allow the dust to be collected and eventually routed to the exhaust port  5  and eventually disposed through the exhaust tubing  32 A and exhaust port  32 . 
   The sanding disc  17  is secured with a disc bolt  19  that is mated to a set of internal threads that are found on the end of the central drive shaft. During the operation of this device, the sanding disc can be easily replaced by unscrewing the bolt and replacing the disc without disturbing the impeller ring or gear mechanism. 
   Around the perimeter of the impeller housing  6  will be a series of flexible brushes  7 . The purpose of the brushes is to capture the dust as it is generated while using the sander. When the device is operated the brushes would be placed against the wall as the device is used. 
   As the dust is generated and due to the vacuum that is created by the impeller ring the dust will travel in the direction of vacuum and eventually be directed to an exhaust port duct  5  that is part of the impeller casing  6 . An exhaust hose  32 A is attached to the exhaust port duct  5 .