Patent Publication Number: US-7722438-B1

Title: Air blow functionality for disc sander

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is directed toward an air blow device for a dual action disc sander. 
   2. Description of Related Art 
   In modern manufacturing plants and vehicle repair facilities, it is common to have pneumatic tools for performing manufacturing/repair related tasks. These pneumatic tools use compressed air as an energy source for operation. The compressed air is supplied by a main air supply line that provides large volumes of air at a set pressure. 
   The pneumatic tool may be, for example, a drill for drilling holes, a saw for cutting materials, or a dual action (DA) disc sander for sanding/polishing a surface. The pneumatic tools are lightweight and traditionally operate at high speed. By operating at high speed, the pneumatic tool can quickly complete the required manufacturing/repair task. 
   Traditionally, a worker is faced with multiple tasks that must be performed at the worker&#39;s workstation. These tasks may or may not be related. For example, the worker may need to drill a hole in an object and then tighten a fastener that extends through the recently drilled hole. Alternatively, the tasks may be somewhat diverse in nature and only related in that the first task precipitated the second task. 
   For example, the worker may use the DA sander to sand/polish a portion of a painted surface (hereinafter “work area”) of a vehicle (hereinafter “workpiece”). Unfortunately, the DA sander creates airborne dust and/or debris. As such, the dust/debris may settle in/on an area of the vehicle that is not adjacent to the workpiece (hereinafter “non-work area”). Further, the non-work area where the dust/debris settles may be a somewhat confined space with reduced accessibility. 
   Known in the art are pneumatic tools that cut, drill, or sand (hereinafter “work”) with a blade, drill bit, or mounting disc with sandpaper (hereinafter “tool piece”), that also expel pressurized air to clear dust or debris from around the work area. Such known pneumatic tools expel the pressurized air through the nozzle any time that the tool piece is active, so as to remove dust/debris from the around the work area as the dust/debris is created. While these known pneumatic tools are effective in removing dust/debris from the workpiece during operation of the tool piece, the tools are ineffective in removing dust/debris from the non-work areas (i.e., areas remote from the work area). 
   Traditionally, when dust/debris settles onto the non-work area, the worker could disconnect the pneumatic tool from the main air supply line and attach an air blow gun to remove the dust/debris from the non-work area. However, disconnecting the tool and connecting the air blow gun takes additional time and effort. In a manufacturing/repair environment, the worker may opt to not remove the dust/debris from the non-work area to avoid suffering from the lost productivity attributed to changing from the tool to the air blow gun. Alternatively, dedicated air blow guns may be used to remove the dust/debris from the non-work area. However, such an arrangement is expensive and requires additional compressed air connections and space that may not be available in the manufacturing/repair environment. 
   Unfortunately, when dust/debris is allowed to remain in the non-work area, problems on the downstream manufacturing line or in the repair facility may be encountered. For example, the dust/debris may later become airborne again and settle in a still wet paint area of the vehicle, resulting in an appearance defect. Alternatively, the dust/debris may become dislodged during some other subsequent operation during which dust/debris is not tolerated (e.g. during final assembly) or after the vehicle is delivered to the customer. 
   Therefore, there exists a need in the art for an apparatus and method to permit a worker to operate an air blow device without operating the tool piece of the tool. 
   SUMMARY OF THE INVENTION 
   The present invention is directed toward an apparatus and method for a pneumatic tool. In particular, the present invention includes a tool piece for engaging a workpiece and an air blow device with a nozzle on the pneumatic tool for displacing dust/debris from the workpiece. 
   More specifically, the nozzle displaces dust/debris that was created by the tool piece or otherwise, and the air blow device is operated independent of the tool piece. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the invention will be apparent with reference to the following description and drawings, wherein: 
       FIG. 1  is a perspective view of a disc sander according to the present invention; 
       FIG. 2  is a top plan view of the disc sander of  FIG. 1 ; 
       FIG. 3  is a pneumatic circuit of the present invention; and 
       FIG. 4  is a flow chart illustrating steps of a method according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIGS. 1 and 2 , a pneumatic tool  10  according to the present invention includes a dual action (DA) sander  12  with an air blow device  14 . In addition, the pneumatic tool  10  includes a main inlet  16 , and a manifold  18  that is fluidly connected to a DA inlet  20  and an air blow inlet  22 . The DA inlet  20  is connected to a DA supply line  24 . The air blow inlet  22  is connected to an air blow supply line  26  that travels near a housing  28  of the DA sander  12 . The air blow supply line  26  terminates at an air blow valve  30 , having an actuating button  32 , and the air blow valve  30  is fluidly connected to a nozzle  34 . The air blow valve  30  includes a first section  36  and a second section  38 . 
   On top of the DA sander  12  is an actuator  40  and on bottom of the DA sander  12  is a tool piece  42  with sandpaper  44  and a related mounting disc  46 . As shown in  FIG. 3 , an entry channel  48  is fluidly connected to a rotary air vane  50 . The rotary air vane  50  is also fluidly connected to an exit channel  52 . The entry channel  48 , rotary air vane  50 , and exit channel  52  are disposed inside of the housing  28 . On back of the DA sander  12  is an exhaust port  54  with a muffler  56 . 
   As mentioned hereinbefore, the area that the tool piece  42  of the DA sander  12  engages on the workpiece to sand/polish is referred to as a work area (not shown). Any other area on the workpiece that is not engaged by the tool piece  42  is known as a non-work area (not shown). 
   To aid in understanding of the present invention,  FIG. 3  illustrates a pneumatic circuit of the present invention. An air compressor (not shown) via a main air supply line (not shown) supplies compressed air to the tool  10  via the main inlet  16 , as is known in the art. The compressed air is then communicated to the manifold  18 . Then, the compressed air travels to the air blow inlet  22  and the DA inlet  20 . Compressed air that enters the air blow inlet  22  then travels through the air blow supply line  26  to the air blow valve  30 . A worker (not shown) selectively opens the air blow valve  30  by depressing the actuating button  32 . When the actuating button  32  is depressed, the compressed air travels through the air blow valve  30  and is dispensed by the nozzle  34 . Alternatively, should the actuator  40  be depressed, the compressed air that enters the DA inlet  20  travels through the entry channel  48  of the housing  28 , engages the rotary air vane  50  inside of the housing  28 , and is communicated through the exit channel  52  of the housing  28 . Finally, the air passes through the exhaust port  54  and, optionally, through the muffler  56 . 
   With reference once again to  FIGS. 1-2 , the DA sander  12  selectively drives the tool piece  42 , and hence the mounting disc  46  and the sandpaper  44 , in either a random orbital movement or orbital movement. DA sanders have enjoyed wide commercial success, particularly in the vehicle manufacturing/repair industry, because in the random orbital mode, a very fine finish may be obtained. In addition, when operated in the orbital mode, the DA sander  12  is effective for heavy stock removal, while providing a finish superior to that produced by a typical rotary disc sander. This flexibility in operation of the DA sander  12  is desirable in the vehicle manufacturing/repair industry when painted surfaces must be quickly sanded and/or polished. While the pneumatic tool  10  of the present invention is illustrated as a DA sander  12 , it is understood that the tool  10  and related tool piece  42  could instead be, for example, a pneumatic grinder, pneumatic drill, pneumatic file, or pneumatic saw. 
   The main inlet  16  is illustrated as a quick connect fitting. The quick connect fitting is utilized to allow rapid attachment and detachment of the tool  10  from the main air supply line. The main air supply line has a complimentary fitting for fluid connection to the main inlet  16  of the present invention. Furthermore, as is also known in the art, the quick connect fitting provides for interchangeability between various types of pneumatic tools and the main air supply line. 
   Attached to the main inlet  16  is the manifold  18 . The manifold  18  is generally cylindrical in shape and is hollow to allow fluid communication between the main inlet  16  and the DA inlet  20  and the air blow inlet  22 . However, other shapes for the manifold  18  are possible and contemplated. Because of the manifold  18 , the DA inlet  20  and the air blow inlet  22  airflows are parallel and operational issues are reduced. In particular, a pressure of about 90 p.s.i. and a flow rate of about 17 s.c.f.m. are supplied to either the tool piece  42  or the nozzle  34 . This is in direct contrast to the known tools that supply the components in series or power the air blow device from the exhaust of the tool. The layout of the actuating button  32  of the air blow device  14  and the actuator  40  of the DA sander  12  encourages independent and exclusive operation of the air blow device  14  or the DA sander  12 . 
   As illustrated, the DA inlet  20  axially extends from the manifold  18  on a side opposite that of the main inlet  16 . The air blow inlet  22  extends in a vertical direction from the manifold  18  before changing direction to be generally parallel to the manifold  18 , having what could be described as a sideways L-shape. 
   The air blow supply line  26  has a hollow tube-like construction with an inner diameter. The air blow supply line  26  extends in a generally horizontal direction from the air blow inlet  22  and closely follows the curvature of the housing  28  of the DA sander  12 , so as to minimize the possibility of the air blow supply line  26  being caught on nearby objects. The inner diameter of the air blow supply line  26  may be increased or decreased to adjust the pressure and flow rate of the air expelled through the nozzle  34 . 
   The air blow valve  30  is L-shaped including the first section  36  and the second section  38 . The first section  36  is generally cylindrical and extends in a generally horizontal direction from the air blow supply line  26 . The first section  36  is hollow to allow fluid communication between the air blow supply line  26  and the second section  38  of the air blow valve  30 . At an end distal to the connection between the air blow supply line  26  and the first section  36 , the first section  36  attaches to the second section  38 . 
   The second section  38  vertically extends upward from the first section  36 . The actuating button  32  is disposed at an end of the second section  38  distal to the connection between the first section  36  and the second section  38  and is connected to a valve (not shown) disposed in the second section  38  to selectively permit/prevent airflow by depressing/releasing the actuating button  32 . Preferably, the actuating button  32  is biased to an undepressed position corresponding to a closed-valve position. The nozzle  34  extends in a horizontal direction from the second section  38 . The actuating button  32  allows selective fluid communication between the air blow supply line  26  and the nozzle  34 . The air blow valve  30  shown is merely illustrative of a type of fluid control device; any device that allows for fluid control independent of the actuator  40  is possible and contemplated. 
   The nozzle  34  is of a hollow pipe construction. Although illustrated as having solid walls, it is also contemplated that relief holes would be cut or drilled into the walls of the nozzle  34 . This would be especially beneficial to reduce the outlet air pressure when an air pressure of 30 p.s.i. or greater is supplied to the nozzle  34 . 
   Although not illustrated, it is considered apparent the general structure inside of the housing  28  of the DA sander  12  is known in the art. However, for clarity, a brief description of the interior structure will be given. As mentioned hereinbefore, the DA inlet  20  axially extends in a horizontal direction from the manifold  18  on a side opposite that of the main inlet  16 . The actuator  40  allows for selective fluid communication between the DA inlet  20  and the entry channel  48 . The entry channel  48  is fluidly connected to the rotary air vane  50 . 
   The rotary air vane  50  is axially connected to the tool piece  42 . However, the rotary air vane  50  may be connected to the tool piece  42  by any other means that allows rotation of the tool piece  42  when the actuator  40  is depressed and compressed air flows through the rotary air vane  50 . The tool piece  42 , which in the present example is the sandpaper  44  and the mounting disc  46 , is generally circular in shape and has a flat bottom surface for even perpendicular engagement with the workpiece (e.g. the surface that is sanded/polished). 
   It is noted that the nozzle  34 , and the resulting air expelled from the nozzle  34 , is in a direction generally perpendicular to the engagement surface of the tool piece  42  with the workpiece. This allows the nozzle  34  to direct compressed air to locations (non-work areas) that are distinct from the work area. For example, the DA sander  12  can be used to polish a vehicle roof (the workpiece), and then compressed air can be released from the nozzle  34  to displace dust/debris from a door hinge area (the non-work area) of a vehicle, without operating the tool piece  42 . 
   After the air has passed through the rotary air vane  50 , the air is received in the exit channel  52 . The exit channel  52  is fluidly connected to the exhaust port  54 . The exhaust port  54  is also fluidly connected to the optional muffler  56  that is axially attached to the exhaust port  54 . The muffler  56  is generally cylindrical in shape and may contain baffles or other structures to retard the speed of the air that is dispensed from the exhaust port  54 , as is known in the art. 
   As shown in  FIG. 4 , a method of using the present invention will now be discussed. It should be noted that it is assumed that the present invention is already attached to the main air supply line and a sufficient pressure and amount of compressed air is being supplied to the tool. Typically, the compressed air has a pressure of about 90 p.s.i. and a flow rate of about 17 s.c.f.m. However, other flow rates and pressures are possible and contemplated. In Step  100 , the actuator  40  is depressed by the worker, and the tool piece  42  rotates while the nozzle  34  does not expel compressed air. The tool piece  42  is placed in engagement with the workpiece (Step  105 ). In Step  110 , the actuator  40  is released and the tool piece  42  stops rotating. Then the worker directs the tool  10 , and specifically, the nozzle  34  to an area away from the workpiece (i.e., toward the non-work area), and depresses the actuating button  32  of the air blow valve  30  (Steps  115 ,  120 ) and thereby directs a stream of pressurized air forward. In Step  125 , the worker closes the air blow valve  30  by removing pressure from the actuating button  32  and compressed air stops flowing from the nozzle  34 . 
   The present invention offers numerous benefits over the known pneumatic tools. The present invention provides that the tool piece  42  and the nozzle  34  are intended to be separately operated. In particular, the nozzle  34  selectively expels pressurized air to the non-work area independent of the operation of the tool piece  42 . Because of this, dust/debris can be removed without operation of the tool piece  42 . Furthermore, because the nozzle  34  is generally perpendicular to the tool piece engaging surface, the nozzle  34  may be directed to blow pressured air to areas with reduced accessibility that would be difficult to reach if the nozzle  34  were parallel to the tool piece engaging surface space. Finally, because the nozzle  34  and the tool piece  42  are powered from the compressed air in the manifold  18  in a parallel arrangement, operational issues such as inadequate air flow or air pressure are reduced. This layout of the actuating button  32  and the actuator  40  promotes independent operation of the air blow device  14  and the DA sander  12 . 
   As described hereinabove, the present invention solves many problems associated with previous type devices. However, it will be appreciated that various changes in the details, materials and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art without departing from the principle and scope of the invention, as expressed in the appended claims.