Abstract:
The present invention relates generally to an apparatus for applying texture materials to wall and ceiling surfaces, and more particularly to an improved hopper gun with an internal air control valve for controlling the on and off function of the atomizing air stream and an integrated flow control valve to manage the volume/pressure ratio of the pressurized atomizing air. The air control valve and flow control valve integrated into the improved hopper gun provides improved control over the texturing process and simplified operation of the improved hopper gun.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to an apparatus for applying texture materials to wall and ceiling surfaces, and more particularly to an improved hopper gun with an internal air control valve for controlling the on and off function of the atomizing air stream and an integrated flow control valve to manage the volume/pressure ratio of the pressurized atomizing air. The air control valve and flow control valve integrated into the improved hopper gun provides improved control over the texturing process and simplified operation of the improved hopper gun. 
   Hopper guns are well known in the art. U.S. Pat. No. 4,863,104 to Masterson teaches a spray gun for applying ceiling acoustic textures using compressed air. A method is described therein where material to be sprayed onto a surface is gradually mixed with a compressed stream of fast moving air. A reservoir above the gun holds the material to be applied, and the material drains before a nozzle that emits forced air, entraining the mixture and the air in a stream that is delivered to the intended surface. The invention disclosed in the Masterson patent was an improvement over prior art in both efficiency and reliability. U.S. Pat. No. 5,979,797 to Castellano discloses a hopper gun wherein a low pressure air supply is used to spray the material and also to force material out of the hopper in a reliable manner. U.S. Pat. No. 5,393,034 to Mendez discloses an air valve for a hopper gun having a male quick disconnect air inlet fitting that feeds pressurized air into an inlet end of a longitudinal rearwardly movable trigger actuated air stem for propelling texture coating mixture and the like onto a surface to be coated. The air shut off valve comprises a tubular valve stem disposed within the air stream of the hopper gun such that an open first end of the valve stem lies within the male quick disconnect air fitting proximal to the inlet aperture of the fitting. The fitting has at least one air inlet port through a wall thereof proximal the first end thereof. The teachings of the Masterson, Castellano, and Mendez patents are incorporated by reference herein in furtherance of the understanding of the present invention. 
   The prior art can effectively apply the texture materials to the intended surface, but improvements are still possible to make the devices more reliable and more efficient. One problem that occurs in prior art hopper guns is that they are typically equipped with a peripherally disposed non-integrated ball valve for controlling the on/off function of the pressurized atomizing air. The ball valve is generally located below the handle of or behind the hopper gun and requires manual rotary actuation. This is generally not convenient for the operator. 
   Additionally, during setup for the application process the volume/pressure ratio of the pressurized atomizing air needs to be managed to assist in achieving a desired texture pattern. Prior art hopper guns also required the ball valve to perform a dual role. In addition to performing its primary function of starting and stopping the flow of pressurized atomizing air through the hopper gun, the ball valve is also used for controlling the volume/pressure ratio of pressurized atomizing air. This means volume/pressure has to be readjusted each time the pressurized atomizing air is shut off. Restarting the pressurized atomizing air involves an adjustment of the handle of the ball valve to some undefined intermediate position. 
   Having to continually adjust and readjust (for example when refilling the hopper) the volume/pressure ratio during the application process without any defined parameters leads to inconsistencies in the texture pattern produced by the hopper gun. The present invention seeks to overcome this problem by integrating a dedicated flow control valve into body of the hopper gun that controls the volume/pressure ratio produced by the hopper gun. This feature is exclusive of the on/off function for the pressurized atomizing air stream allowing it to be set one time at the beginning of the application process and left at that setting for the duration of the application process. 
   SUMMARY OF THE INVENTION 
   The present invention is a hopper gun incorporating a design that allows for the successful inclusion of an integrated air control valve and a separate integrated airflow control valve. The unique design of the air control valve insures complete atomization of the texturing material. This is accomplished by initiating the pressurized atomizing air prior to its convergence with the texturing material. This involves the incorporation of several codependent components and is realized with a single initiation action. In the present invention&#39;s static state, a poppet is spring-biased against a poppet housing, closing off the pressurized atomizing air&#39;s discharge from the hopper gun. The trigger of the hopper gun has a tangent relationship to the sleeve housing of the air control valve. When the trigger is retracted to start the texturing process, the tangent relationship on the trigger engages the front face of the sleeve housing forcing the sleeve housing rearward. As the sleeve housing travels rearward, the sleeve housing&#39;s distal end abuts the poppet. The opposing force applied by the trigger overcomes the poppet&#39;s spring-biased position. This in turn moves the poppet rearward unseating the poppet from the poppet housing and allows the discharge of the pressurized atomizing air. Further retraction of the trigger causes the sleeve housing to abut a shoulder of the poppet housing. 
   The poppet housing, which is rigidly coupled to a compressed air stem through a threaded connection, moves rearward with the air stem. As the coupled poppet housing and air stem move rearward, the tip of the air stem unseats from the texture material orifice located at the front of the hopper gun. The unseating from the texture material orifice and rearward movement of the air stem allows the texture material to become entrained and aerated/atomized by the pre-existing pressurized atomizing air. The aerated/atomized texturing material is then discharged out of the hopper gun on to the surface being textured. When the trigger is released, the tip of the air stem reseats against the material orifice, which shuts off the texturing material prior to the poppet reseating against the poppet housing. This delay in shutting off the pressurized atomizing air until after the texturing material has been shut off insures complete aeration/atomization and discharge of the texturing material. The complete aeration/atomization of the texture material insures a consistent texture pattern throughout the entire application process. 
   An additional feature of the present invention is an airflow control valve that is integrated into the hopper gun. The airflow control valve is located on the hopper gun for convenience of the operator. The airflow control valve incorporates an orifice into its design. The orifice of the airflow control valve intersects an air passage of the hopper gun that communicates the pressurized atomizing air into the hopper gun. Rotary manipulation of an adjusting knob on the airflow control valve reorients the orifice&#39;s registration with the air passageway. This interaction between the air passageway and the orifice of the airflow control valve controls the flow of air from a completely unrestricted flow to a substantially restricted flow of pressurized atomizing air through the air passageway. This provides the user with a variable control of the volume/pressure ratio of the pressurized atomizing air as its supplied through the hopper gun. As a separate mechanism of the internal air control valve the flow control valve, the airflow control valve allows the volume/pressure ratio to be initialized to an appropriate level for the particular application at the start of the texturing process, and maintained in that state for the duration of the process or easily adjusted if a change in texture pattern is desired. 
   Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features of the invention 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view, in cross section, of a first preferred embodiment of the present invention; 
       FIG. 2  is an enlarged, cross sectional view of the valve of the embodiment of  FIG. 1  in the closed configuration; and 
       FIG. 3  is an enlarged, cross sectional view of the valve of the embodiment of  FIG. 1  in the open configuration. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates the general features of the hopper gun  10  of the present invention, comprising a handle  12 , a trigger  14 , and a body portion  15 . The trigger  14  is hinged to the body portion  15  of the gun  10  at pivot pin  16 , as by a yoke section (not shown) that allows the trigger to pass over the body portion of the gun. The lower portion of the trigger  14  forms a finger grip  19  that is elongate and extends downward with recesses  18  on a front surface adapted to receive a portion of first, second, third, and fourth fingers to facilitate gripping and squeezing the trigger toward the handle  12 . The finger grip  19  may be covered with a soft or resilient material to lessen stress on the fingers and provide some relief to users who may use the hopper gun  10  for many hours at a time. The mounting of the trigger  14  at pivot pin  16  allows the trigger to move between a forward position and a rearward position, which as explained more fully below controls the flow of air through the gun. 
   The handle  12  incorporates an air inlet  22 . Air inlet  22  is preferably threaded, allowing the attachment of a variety of industry standard air hoses to hopper gun  10 . The air hose (not shown) supplies the pressurized atomizing air necessary for aerating/atomizing the texture material. The pressurized atomizing air supplied by the air hose attached at air inlet  22  is directed into air passageway  24 . Intersecting air passageway  24  is the airflow control valve  26  that incorporates a hollow orifice  28 . A knob (not shown) of the airflow control valve can be rotated up to 90 degrees. This allows orifice  28  to be either completely aligned with air passageway  24 , partially aligned with air passageway  24 , or completely misaligned with air passageway  24 . The degree of alignment or misalignment between orifice  28  and air passageway  24  determines the volume/pressure ratio produced by hopper gun  10 . Consistently controlling the volume/pressure ratio is one of the factors that insures a repeatable texture pattern is produced by hopper gun  10 . 
   Hopper gun  10  also includes a hopper boss  34  for attaching the hopper (not shown). The hopper is a generally funnel shaped container with a partial closure on the top surface and cylindrical opening on the bottom surface. The cylindrical opening at the bottom of the hopper is dimensionally compliant to the outside diameter of the hopper boss  34  and attached to the hopper gun  10  by means of a mechanical clamp (not shown). The hopper boss  34  is open ended at a top surface and defined by a generally cylindrical wall  30 . The hopper allows storage of texture materials to be used during the application process. The texture material flows out of the hopper and through the hopper boss  34  to the staging chamber  36  via gravity. When the hopper gun  10  is in its static state as shown in  FIG. 1 , no texture material can pass through the material orifice  32 . However, when trigger  14  is retracted, tip  40  of the air stem  38  unseats from the material orifice  32  and atomizing area  37  is exposed. The texture material flows into the atomizing area  37 , where it converges with the pre-existing pressurized atomizing air. The texture material is aerated/atomized in atomizing area  37  then expelled from the hopper gun  10  through the material orifice  32  and on to the surface being textured. 
   Assuming the adjustable volume/pressure ratio of the pressurized atomizing air is constant, the lateral distance between tip  40  of the air stem  38  and material orifice  32  during the application process is one factor that determines the type of texture pattern produced. As tip  40  of air stem  38  moves laterally away from the material orifice  32 , the amount of texture material in atomizing area  37  increases. The increased amount of texture material in atomizing area  37  changes the texture pattern produced by hopper gun  10 . A higher ratio of texture material to pressurized atomizing air results in a heavier (larger) texture pattern and vice versa. To control the amount of lateral distance tip  40  of air stem  38  travels when trigger  14  is retracted, an adjustable stop  46  is incorporated into the hopper gun  10 . In addition to acting as a positive stop, the adjustable stop  46  also houses spring  74 . Spring  74  is spring-biased opposite the force applied when trigger  14  is retracted. When trigger  14  is in its static neutral state, spring  74  applies force to components of the integrated air control valve shutting off the pressurized atomizing air by seating o-ring  68  of poppet  52  against seat  70  of poppet housing  54 , which further shuts off texture material from discharging out the front of hopper gun  10  by seating tip  40  of air stem  38  against material orifice  32 . When trigger  14  is taken out of its static neutral state and retracted, it abuts face  82  of sleeve housing  66  causing sleeve housing  66  to move back along the cylindrical projection  59  of the poppet housing  54  until face  73  of sleeve housing  66  abuts shoulder  86  of poppet  52 . 
   Continued rearward retraction of trigger  14  overcomes the existing spring biased condition produced by spring  74 , and unseats o-ring  68  of poppet  52  from seat  70  of poppet housing  54 . This unseating of o-ring  68  allows the pressurized atomizing air to flow through air passage  56  of poppet housing  54  and air stem  38 , through orifice  60 , through material orifice  32  and out of the front of hopper gun  10 . Air stem  38  is rigidly coupled to poppet housing  54  by a threaded male/female relationship. Continued retraction of trigger  14  causes the inside face  90  of sleeve housing  66  to abut face  94  of poppet housing  54  causing poppet housing  54  and air stem  38  to travel laterally rearward resulting in tip  40  of air stem  38  unseating from material orifice  32 , creating atomizing area  37 . Continued retraction of the trigger  14  results in chamfer  63  of poppet  52  abutting face  81  of adjustable stop  46 . The abutment of chamfer  63  of poppet  52  and face  81  of adjustable stop  46  stops trigger  14  retraction and provides a positive control mechanism for establishing the distance between tip  40  of air stem  38  and material orifice  32  on a repeatable basis. Adjustable stop  46  also has a threaded relationship  50  with threaded bushing  85 . Turning adjustable stop  46  either clockwise (forward) or counter-clockwise (rearward) results in the lateral displacement of face  81  of adjustable stop  46  and determines at what point chamfer  63  of poppet  52  abuts face  81  of adjustable stop  46 . 
   The series of abutted relationships between trigger  14  sleeve housing  66  poppet housing  54  poppet  52  and adjustable stop  46  results in the ability to positively and repeatedly control the lateral distance between tip  40  of air stem  38  and material orifice  32  during the application process. The ability to control the distance between tip  40  of air stem  38  and material orifice  32  during the application process is one factor that insures a repeatable texture pattern. 
   In  FIGS. 2 and 3 , the operation of the air valve structure is more clearly illustrated. When no retraction force is being applied to the trigger  14  of hopper gun  10  ( FIG. 2 ), tip  40  of the air stem  38  abuts the material orifice  32 , and atomizing area  37  is occluded by air stem  38 . As set forth above, the air stem  38  is rigidly coupled to the poppet housing  54 , by a threaded male/female relationship, with a common air passage  56  extending through both the poppet housing  54  and the air stem  38  until air passage  56  narrows at the distal end of air stem  38  resulting in air orifice  60  of air stem  38 . At the proximal end of air passage  56  is receiver area  62  of the poppet housing  54 . Receiver area  62  of poppet housing  54  accepts a cylindrical alignment projection  76  of the poppet  52 . Since cylindrical alignment projection  76  of poppet  52  remains registered in receiver area  62  of poppet housing  54  at all times, poppet  52  can move laterally rearward unseating o-ring  68  of the poppet  52  from seat  70  of the poppet housing  54  without having poppet  52  become misaligned from poppet housing  54 . When trigger  14  is in a neutral static state as represented in  FIG. 1 , the spring-biased condition produced by spring  70  forces the poppet  52  forward until o-ring  68  of the poppet  52  seats against seat  70  of the poppet housing  54 . In this condition the sleeve housing  66  is also in a neutral state and the force is relieved between face  73  of the sleeve housing  66  and shoulder  86  of the poppet  52 . With o-ring  68  of the poppet  52  seated against seat  70  of the poppet housing  54 , the pressurized atomizing air is unable to enter air passage  56 , the common air passage for poppet housing  54  and air stem  38 . This condition (demonstrated in  FIG. 2 ) effectively shuts off the pressurized atomizing air from being expelled through the front of the hopper gun  10 . 
   Pressurized atomizing air entering hopper gun  10  at air inlet  22  flows through air passageway  24  until it encounters orifice  28  of flow control valve  26 . The pressurized air is forced through orifice  28  of flow control valve  26 , where its volume/pressure ratio is adjusted to the desired level. After passing through orifice  28  of flow control valve  26 , the pressurized atomizing air flows into air staging area  99  and through two opposed cross-holes (not shown) located at the distal end of sleeve housing  66 . With trigger  14  in its neutral static state as shown in  FIG. 2 , the pressurized atomizing air stream is restricted from entering receiver area  62 . As the trigger  14  is retracted, a set of radius bosses on a yoke (not shown) of the trigger  14  abuts face  82  of sleeve housing  66  causing sleeve housing  66  to move laterally rearward along cylindrical portion  59  creating gap  80 . As the sleeve housing  66  travels laterally away from air stem  38 , the distal face  73  of the sleeve housing  66  abuts the shoulder  86  of the poppet  52  causing poppet  52  to move laterally away from poppet housing  54 . As poppet  52  moves laterally away from poppet housing  54  the o-ring  68  of the poppet  52  unseats from seat  70  of the poppet housing  54  as shown in  FIG. 3 , creating an air passageway for the previously restricted pressurized atomizing air to enter the receiver area  62  at the proximal end of air passage  56 . The pressurized atomizing air enters air passage  56  and is forced through air orifice  60 , passing through material orifice  32  and is expelled from the front of hopper gun  10 . However because air stem  38  has not moved, tip  40  of air stem  38  remains seated against material orifice  32  and texture material present in staging chamber  36  remains in a static state and is unable to flow into atomizing area  37 . 
   Further retraction of trigger  14  results in face  90  of sleeve housing  66  abutting face  94  of poppet housing  54 , forcing poppet housing  54  and air stem  38 , which are rigidly coupled, to move laterally rearward unseating tip  40  of air stem  38  from material orifice  32 . The unseating of tip  40  of air stem  38  from material orifice  32  allows texture material previously in a static state in staging chamber  36  to flow into atomizing area  37 . Since the pressurized atomizing air is already established and discharging through orifice  60  of air stem  38  the texture material entering atomizing area  37  is aerated/atomized. The aerated/atomized texture material is then forced through material orifice  32  out of hopper gun  10  and on to the surface being textured. Complete retraction of trigger  14  is achieved when chamfer  63  of poppet  52  abuts face  81  of adjustable stop  46 . 
   Releasing trigger  14  removes the force generated when trigger  14  is retracted and returns the spring-biased condition created by spring  74  to create a force. An additional force present in hopper gun  10  is that provided by the pressurized atomizing air. These two forces work in concert, systematically controlling the reversal of the abutted relationships created when trigger  14  is retracted. Spring  74  applies a lateral force to poppet  52 , which moves poppet  52  forward while maintaining the pre-existing relationship between face  73  of sleeve housing  66  and shoulder  86  of poppet  52 . The pressurized atomizing air&#39;s force interacts with interfering and restrictive surfaces of the poppet housing  66  and the air stem  38 , forcing them forward. These separate but simultaneous forces allow tip  40  of air stem  38  the seat against material orifice  32 , shutting off the flow of texture material prior to o-ring  68  of poppet  52  reseating against seat  70  of poppet housing  54 . With the pressurized atomizing air still established, all of the texture material allowed into atomizing area  37 , before it was occluded by air stem  38 , is completely aerated/atomized. Poppet  52  continues to be forced laterally forward, which also forces sleeve housing  66  forward closing gap  80 . When gap  80  is nearly closed, o-ring  68  of poppet  52  reseats itself against seat  70  of poppet housing  54 , shutting off the flow of pressurized atomizing air through hopper gun  10 . 
   From the foregoing, it can be seen that an initial retraction of trigger  14  of hopper gun  10  institutes a fully effective air flow through hopper gun  10 , but no texture material can be aerated/atomize until trigger  14  is retracted further unseating tip  40  of air stem  38  from material orifice  32  and creating atomizing area  37 . In atomizing area  37 , the pre-existing pressurized atomizing air and the texture material are allowed to converge and the texture material is aerated/atomized. The aerated/atomized texture material is discharged from hopper gun  10  through material orifice  32  and on to the surface being textured. Inversely, when trigger  14  is released, tip  40  of air stem  38  moves laterally forward seating against material orifice  32  shutting off the discharge of texture material from hopper gun  10 , but since o-ring  68  of poppet  52  hasn&#39;t seated against face  70  of popper housing  70 , the pressurized atomized air continues to flow through hopper gun  10 . The aforementioned pre-initiation of the pressurized atomizing air flow prior is convergence with the texture material when the trigger  14  is retracted, and the blocking of the texture material entering the staging area prior to shutting off the pressurized atomizing air when trigger  14  is released insures complete aeration/atomization of the texture material throughout the entire texturing process. 
   The foregoing description is intended to be illustrative of the concept of the present invention, but not limit the scope of the invention to the just described embodiments. Rather, one of ordinary skill in the art will readily appreciate that there are many modifications and substitutions that can be made to the operation of the air valve that will carry out the present invention, and said modifications and substitutions are intended to be incorporated into the scope of the invention. Therefore, the scope of the invention is intended to be limited only by the ordinary and customary meaning of the words and terms of the claims appended hereto.