Patent Publication Number: US-9889456-B2

Title: Drywall texture application device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/983,065 filed on Apr. 23, 2014. The above identified patent application is herein incorporated by reference in its entirety to provide continuity of disclosure. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a device for applying drywall joint compound to a surface in a textured manner. 
     BACKGROUND 
     Drywall joint compound has long been used in building construction to create various surface textures on ceilings and walls. Different drywall textures, such as orange peel, knockdown, or stucco, provide different aesthetic and acoustic effects. Devices and apparatuses for applying drywall joint compound, also known as “drywall mud,” exist in the prior art. These devices typically mix drywall texture material and water to form drywall mud and then mix the mud with a stream of compressed air, which forces the mud out of a nozzle onto the surface to be coated. Other devices exist that utilize pre-mixed drywall mud. 
     Drywall texture application devices are commonly designed for commercial uses including, for example, applying texture to large surface areas such as building interior and exterior walls. These devices are typically mounted on a vehicle bed or towed as a trailer. Such devices tend to be costly and require extensive training in order to be used safely, making them impractical for personal use. Therefore, it is desirable to provide a device that allows an untrained individual to safely and easily apply drywall joint compound to a surface to create a desired drywall texture. 
     Portable drywall sprayers known as hoppers that feeds texture material to an attached spray gun. These devices typically rely on gravity to feed drywall mud vertically from the hopper to the spray nozzle. Consequently, this and similar devices are difficult to use for coating ceilings and other overhead surfaces because tilting the hopper horizontally interrupts the flow of texture material to the spray gun. It is therefore desired to provide a device that can be easily filled with drywall joint compound and can be used to apply texture to ceilings and other overhead surfaces. 
     Other types of drywall texture devices exist in the art, including shoulder-mounted texture sprayers. Such devices tend to be unwieldy and cause difficulty when applying texture to ceilings or other overhead surfaces. Another drawback of this and other similar devices is that they utilize an inflatable bag to move drywall mud to a spray gun, which is prone to rupture and may cause the device to fail. Therefore, it is desired to provide a handheld drywall texture application device with minimal mechanical elements that is designed such that it can be easily and comfortably used to apply texture to ceilings and other overhead surfaces. 
     There exists portable drywall application devices in the prior art that allow users to customize the texture pattern by changing the rate of the compressed air flow. However, there are many commonly used drywall texture patterns, such as knockdown, orange peel, and stucco. Whether freshly applying a particular texture or matching a texture for patch jobs, calibrating the device requires a trial and error process. Therefore, a device that can accommodate a plurality of nozzle fittings, each of which provides a particular texture pattern, is desired. 
     In view of the above recognized problems, therefore, it is desired to provide a handheld drywall texture application device that is both safe and easy for personal use that can be used to apply drywall texture to any surface. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing disadvantages inherent in the known types of drywall texture application devices now present in the prior art, the object of the present invention is to provide a drywall texture application device having a hollow tube having a first end and a second end, a piston slidably disposed within the hollow tube, a ramrod attached to the piston and extending toward the second end of the tube, and a spray nozzle connected to the first end of the hollow tube, the spray nozzle having an inner channel, a fluid nozzle, an air cap having an inner aperture interchangeably attached thereto, and a connector connectable to an external air source. 
     Another object of the present invention is to provide a handheld drywall texture application device that has an air cap having one or more outer apertures disposed around the inner aperture, the one or more outer apertures being in fluid communication with the external air supply via the connector. 
     A further object of the present invention is to provide a handheld drywall texture application device where the spray nozzle inner channel comprises a first chamber having an inlet in communication with the hollow tube and an outlet in communication with the fluid nozzle, and a second chamber having an inlet in communication with the connector and an outlet in communication with the air cap, wherein depressing the piston causes material within the tube to be forced into the first chamber and expelled therefrom through the fluid nozzle. 
     Still a further object of the present invention is to provide a handheld drywall texture application device having an air cap having an inner aperture removably attached to a spray nozzle around a fluid nozzle, and at least one outer aperture disposed around the inner aperture, wherein air from an external air source exits through the at least one outer aperture and disperses the material expelled from the fluid nozzle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout. 
         FIG. 1  shows a perspective view of a device according to an embodiment of the present invention. 
         FIG. 2  shows an exploded cross-sectional view of a device according to an embodiment of the present invention. 
         FIG. 3A  shows a cross sectional view of an air cap element from an embodiment of the present invention. 
         FIG. 3B  shows a cross sectional view of an air cap element from an embodiment of the present invention. 
         FIG. 3C  shows a cross sectional view of an air cap element from an embodiment of the present invention. 
         FIG. 4  shows a cross-sectional view of a spray nozzle element from an embodiment of the present invention 
         FIG. 5  shows a perspective view of a device according to one embodiment of the present invention in operation. 
         FIG. 6  shows an exploded cross-sectional view of a device according to an alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the device. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for applying drywall texture to a surface. The figures are intended for representative purposes only and should not be considered limiting in any respect. 
     Referring now to  FIG. 1 , a perspective view of a drywall texture application device according to the present invention is shown. The device generally comprises a hollow tube  11  having a first end and a second end, a spray nozzle  12  having a connector  14 , a piston (not visible in this figure), and a ramrod  15 . The spray nozzle  12  is removably attached to the hollow tube  11 . 
     In order to operate the device, a user must first fill the hollow tube  11  with drywall mud. First, the user removes the spray nozzle  12  from the hollow tube  11  and moves piston into an actuated position by depressing the ramrod  15 . The user then inserts the first end (the open end) of the tube  11  into a container of drywall compound that has previously been hydrated, hereafter referred to as drywall mud, and pulls the ramrod  15  out past the second end of the hollow tube  11 , which draws the drywall mud into the tube  11 . The user then reattaches the spray nozzle  12  to the first end of the filled hollow tube  11 . When the spray nozzle  12  is secured to the first end of the hollow tube  11 , any drywall mud within the interior volume of the tube  11  is held therein until emitted by the user. 
     The device also comprises an air hose  16  which is removably attached to the connector  14 . In a preferred embodiment, and as depicted herein, the connector  14  is a ball valve. The ball valve  14  is threadably connected to the spray nozzle  12  at one end and to the air hose  16  at the other end, which is in turn connected to an external compressed air source (not shown). To operate the device, a user moves the ball valve  14  to an open position, allowing air from a compressed air source to enter the spray nozzle  12 . The user then depresses the ramrod  15 , which forces drywall mud out of the device through the spray nozzle  12 . 
     An air cap  13  having an inner aperture is interchangeably and removably attached to the spray nozzle  12 . The air cap  13  may also comprise one or more outer apertures disposed around the inner aperture. When such an air cap  13  is used, the compressed air disperses the drywall mud via the one or more outer apertures of the air cap  13  after the drywall mud has exited the device through the spray nozzle  12 . 
     Referring now to  FIG. 2 , an exploded view of a device according to one embodiment of the present invention is shown. The device generally comprises a hollow tube  21 , a spray nozzle  30 , a piston  23 , and a ramrod  25 . The ramrod  25  preferably has a fixedly attached handle  26 . The handle  26  may be attached to the ramrod  25  by a variety of means, including a threaded connection or a set screw. A sealing element  22  is attached to the piston  23  and forms a seal with the interior surface of the tube  21 , which in turn prevents drywall mud from exiting through the second end of the tube  21 . In one embodiment of the invention, the sealing element  22  comprises a rubber U-cup. 
     A vent cap  24  is mounted within the tube  21  and prevents the piston  23  from exiting through the second end of the tube  21  when the user pulls back the ramrod  25 . The vent cap  24  has an aperture through which the ramrod  25  may freely slide while preventing drywall mud from exiting through the second end of the tube  21 . The ramrod  25  is then connected to the distal end of the piston  23  via a set screw, threaded connection, or the like. 
     The spray nozzle  30  is removably attached to the tube  21  via a threaded connection to the end cap  33 , which is fixedly mounted within the first end of the tube  21 . As depicted, the spray nozzle  30  is straight, but an angled spray nozzle may also be used. The spray nozzle  30  has apertures at its proximate and distal ends. 
     In one embodiment of the present invention, and as shown in  FIG. 2 , the spray nozzle  30  is connected to the end cap  33  via a first threaded adapter  35  and a second threaded adapter  36 . The second threaded adapter  36  is fixedly attached to the interior surface of the end cap  33 . The threaded adapters  35  and  36  have fluid channels that enable drywall mud to travel from the tube  21  into the spray nozzle  30 . A direct threaded connection between the end cap  33  and the spray nozzle  30  may also be utilized. 
     The spray nozzle  30  comprises an inner channel  41  comprising a first chamber  39  having a first inlet in communication with the interior volume of the tube  21 , a second chamber  40  having a second inlet in communication with a connector  31 , and an outlet through which the drywall mud is expelled. The drywall mud enters the first chamber  39  via the force from the piston  23  that is applied when a user depresses the ramrod  25 . A fluid nozzle  37  that extends past the end of the spray nozzle  30  is disposed within the inner channel  41  and is in fluid communication with the first chamber  39 . When a user depresses the ramrod  25 , drywall mud from the tube  21  is forced into the first chamber  39  and then exits the device through the fluid nozzle  37 . 
     An external air supply (not shown) connects to the second chamber  40  of the spray nozzle  30  via a removably attached air hose  32 . The air hose  32  connects to a connector such as a ball valve  31 , which in turn connects to the spray nozzle  30  via an elbow fitting  34 . When the ball valve  31  is in a closed position, no compressed air may enter the second chamber  40  of the spray nozzle  30 . As a user moves the ball valve  31  towards an open position, compressed air enters the second chamber  40 . 
     An air cap  38  is removably mounted over the fluid nozzle  37  and removably secured to the spray nozzle  30  via a threaded connection. In one embodiment of the present invention, the air cap  38  comprises one or more outer apertures in fluid communication with the second chamber  40 . When the ball valve  31  is in an open position, compressed air flows through the second chamber  40  and exits the device through the outer apertures of the air cap  38 . In operation, the compressed air discharged through the air cap  38  disperses the drywall mud that is forced out of the device through the fluid nozzle  37  by a depression of the ramrod  25 . The number of outer apertures through which the compressed air may flow affects the resulting texture pattern of the drywall mud. Different air caps may be used to create various textures, such as knockdown, stucco, or orange peel. Users may also adjust the ball valve  31  until an air pressure resulting in the desired texture is achieved. 
     Referring now to  FIGS. 3A, 3B, and 3C , cross-sectional depictions of the air caps that may be used with the device are shown. The air caps are removably attachable to the first end of the spray nozzle  30 . The air caps comprise at least an inner aperture  44 . Alternative embodiments of the air caps comprise one or more outer apertures  45  situated around the inner aperture  44 . The air cap is slidably mounted over fluid nozzle  37  and is then removably secured to spray nozzle  30  via a threaded connection. The outer apertures  45  are in fluid communication with the second chamber  40  of the spray nozzle  30  and allow compressed air to be discharged therefrom. 
     The arrangement of the air cap outer apertures  45  affects the texture pattern of the discharged drywall mud, allowing for different texture patterns to be obtained by changing air caps. In operation, compressed air discharged from the air cap outer apertures  45  disperses the drywall mud discharged from the fluid nozzle  37 . The exit pattern and resulting texture of the dispersed drywall mud is determined by the air cap selected by the user. 
     An air cap without outer apertures, such as the one shown in  FIG. 3B , provides the least amount of spread and can be used to apply an orange peel texture or other similar textures. With this air cap, compressed air does not disperse the drywall mud, which is forced through the fluid nozzle  37  by a depression of the ramrod  25 . An air cap with outer apertures  45 , such as the one shown in  FIG. 3C , allows the drywall mud discharged through the fluid nozzle  37  to be dispersed by the compressed air discharged through the air cap outer apertures  45  via the second chamber  40 . The air exiting outer apertures  45  further mixes with the drywall mud exiting through inner aperture  44  to create to a wider splatter pattern. Such air caps can be used to obtain a knockdown texture and other texture patterns that require a greater spread of material and greater atomization than orange peel texture. Adding more outer apertures to the air cap increases the spread of the spray pattern. An air cap that has a greater number of outer apertures  45  such as the one shown in  FIG. 3A  can be used to apply an acoustic or stucco texture pattern, which requires a large spray pattern and a greater distribution of material. 
     The rate at which the user depresses the ramrod  25  varies the feed rate of drywall mud into the first chamber  39  of the spray nozzle  30 , which also affects the resulting texture pattern. Users can depress the ramrod  25  quickly to force more through the fluid nozzle  37  at a faster rate, thereby increasing the amount of material discharged from the device over a period of time. The combination of interchangeable air caps and the user-controlled drywall mud feed rate allows a user to replicate a wide variety of commonly used drywall textures, such as orange peel, stucco, knockdown, and other textures. 
     Referring now to  FIG. 4 , a cross-sectional view of the spray nozzle  30  is shown. In the depicted embodiment of the invention, the attached air cap  38  is one having outer apertures  45  similar to those shown in  FIG. 3A  and  FIG. 3C . The outer apertures  45  are in fluid communication with the second chamber  40 . When a user depresses the ramrod  25 , drywall mud flows from the tube  21  through the first chamber  39  via the fluid nozzle  37  and out of the device. When the ball valve  31  is in an open position, compressed air enters the second chamber  40  and exits the device through the air cap outer apertures  45 , causing the drywall mud to be dispersed into a spray pattern. Different arrangements of the outer apertures  45  change the pattern of the dispersed drywall mud. Users may choose an air cap  38  that generates a desired texture of the dispersed drywall mud. 
       FIG. 5  depicts a device according to the present invention in a disassembled state, ready to be filled with drywall mud. In order to fill the device with drywall mud, a user removes the spray nozzle  60  from the tube  50 . A user then inserts the open end  52  of the tube  50  into a container  100  filled with pre-mixed drywall mud. Next, the user moves the ramrod  54  past the second end  56  of the tube  21  by pulling back on the handle  53 , creating a suction which causes the tube  50  to fill with drywall mud. The user then reattaches the spray nozzle  60  to the tube  50  and attaches an air hose  58  to an external compressed air supply. Once it is filled with drywall mud, a user may aim the spray nozzle  60  towards a surface to be coated, turn the ball valve to an open position, and depress the ramrod  54  using the handle  53 . 
       FIG. 6  depicts an alternative embodiment of the present invention. An angled spray nozzle  130  may be used in place of a straight spray nozzle  30 . The components and principles of operation of the device having an angled spray nozzle  130  remain the same as those in a device having a straight spray nozzle  30 . The angled spray nozzle  130  facilitates the coating of ceilings or other overhead surfaces without requiring the user to hold the device at a substantially vertical angle. While the angled spray nozzle  130  makes it easier to coat overhead surfaces with drywall mud, both the straight and angled embodiments of the present invention may be used interchangeably to coat overhead surfaces or any other surface. 
     It is therefore submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.