Patent Publication Number: US-2021170426-A1

Title: Tip piece for spray tip

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority under 35 U.S.C. § 119 to U.S. provisional application Ser. Nos. 62/945701, entitled “TIP PIECE FOR SPRAY TIP,” filed Dec. 9, 2019, by Samuel R. Stewart, Calvin K. Henrikson, Robert J. Lind, and Jeffrey N. Velgersdyk; the contents of which are all incorporated by this reference. 
    
    
     BACKGROUND 
     The present disclosure relates to fluid spraying systems, and in particular, to a spray tip for fluid spraying systems. 
     Fluid spraying systems are commonly used in a wide variety of applications, from industrial assembly to home painting. Handheld paint sprayers can be used by a human operator, while automated sprayers are typically used in mechanized manufacturing processes. Fluid sprayed by such systems conforms to a spray pattern defined, in large part, by orifice shape and size. Different spray tips, with different orifice shapes and sizes, can be positioned in fluid spraying systems to alter the spray pattern of the fluid being sprayed by the fluid spraying system. Over time, erosion can occur around the orifices of spray tips, casing the spray pattern of the fluid being sprayed to change in an unsatisfactory manner. 
     SUMMARY 
     In one aspect of the disclosure, a tip piece for a sprayer includes a tip body extending axially between a first end and a second end. A passage extends axially inside the tip body from the first end to a terminal end between the first end and the second end of the tip body. A nozzle extends axially into the tip body from the second end of the tip body. An orifice is between the nozzle and the passage and a rounded interface is between the passage and the orifice. The rounded interface has a radius of curvature. 
     In another aspect of the disclosure, a tip piece for a sprayer includes a tip body extending between a first end and a second end. A passage extends inside the tip body from the first end to a terminal end between the first end and the second end of the tip body. A nozzle extends into the tip body from the second end of the tip body and intersects the terminal end of the passage to form an orifice. A rounded interface is formed on a perimeter of the orifice between the nozzle and the terminal end of the passage. 
     In another aspect of the disclosure, a method for forming a tip piece for a sprayer includes forming a tip body with a first end and a second end. A passage is formed into the first end of the tip body and a nozzle is formed into the second end of the tip body. The nozzle intersects the passage to form an orifice between the passage and the nozzle. A perimeter of the orifice is rounded to form a rounded interface between the passage and the nozzle. 
     Persons of ordinary skill in the art will recognize that other aspects and embodiments of the present invention are possible in view of the entirety of the present disclosure, including the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a cart-mounted airless sprayer system. 
         FIG. 2A  is an isometric view of a spray gun. 
         FIG. 2B  is a partially exploded view of the spray gun from  FIG. 2A . 
         FIG. 3  is a cross-sectional view of a spray tip with a tip piece. 
         FIG. 4A  is a perspective view of the tip piece from  FIG. 3 . 
         FIG. 4B  is a top view of the tip piece from  FIG. 4A . 
         FIG. 4C  is a side elevation view of the tip piece from  FIG. 4B . 
         FIG. 5A  is a cross-sectional view of an orifice and passage of the tip piece taken along line A-A from  FIG. 4B . 
         FIG. 5B  is an enlarged view of the orifice and passage of the tip piece taken from circle C of  FIG. 5A . 
         FIG. 6A  is a perspective view of a flat tip. 
         FIG. 6B  is a cross-section view of the flat tip taken along line B-B from  FIG. 6A . 
         FIG. 7  is a perspective view of another embodiment of the tip piece. 
         FIG. 8  is a perspective view of another embodiment of the tip piece. 
         FIG. 9  is a perspective view of another embodiment of the tip piece. 
         FIG. 10  is a perspective view of another embodiment of the tip piece. 
         FIG. 11  is a side elevation view of another embodiment of the tip piece. 
         FIG. 12  is a perspective view of another embodiment of the tip piece. 
         FIG. 13  is a side elevation view of another embodiment of the tip piece. 
     
    
    
     While the above-identified drawing figures set forth one or more embodiments of the invention, other embodiments are also contemplated. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings. Like reference numerals identify similar structural elements. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a perspective view of airless spray system  10 , which includes dolly cart  12 , motor  14 , pump  16 , suction tube  18 , hose  20  and spray gun  22 . Airless spray system  10  comprises a conventional airless spray system that is configured for commercial and residential use. Motor  14  and pump  16  of airless spray system  10  are designed for applying large volumes of fluid or paint during each use. Such a motor and pump are described in U.S. Pat. No. 6,752,067 to Davidson et al., which is assigned to Graco Minnesota Inc. Suction tube  18  is configured to be inserted into a five-gallon pail of fluid that can be suspended from dolly cart  12  with hook  24 . Motor  14  is configured to be connected to a conventional power outlet using a power cord to provide input power to pump  16 . Spray gun  22  is connected to pump  16  using hose  20 , which provides ample length for an operator to roam. 
       FIGS. 2A and 2B  will be discussed concurrently.  FIG. 2A  is an isometric view of spray gun  22 .  FIG. 2B  is a partially exploded view of spray gun  22 . Spray gun  22  includes gun body  26 , trigger  28 , handle  30 , tip mount  32 , tip  34 , tip piece  36 , connector  38 , and valve  40 . Gun body  26  includes mounting surface  42 . 
     Gun body  26  is mounted on handle  30 . Connector  38  is attached to a bottom of handle  30  and is configured to attach to an end of hose  20  (shown in  FIG. 1 ) that supplies fluid to spray gun  22  under pressure. Connector  38  can be of a quick disconnect type, or any other desired type of hose connector. Handle  30  can be formed from polymer or metal. Handle  30  is configured to be gripped by one hand of a user to hold, support, and aim spray gun  22  while also allowing the user to actuate trigger  28 . Gun body  26  can be formed of any suitable material for receiving various components of spray gun  22  and for providing a pathway for pressurized fluid. In some examples, gun body  26  is formed from a metal, such as aluminum. 
     As shown in  FIG. 2B , valve  40  is disposed within gun body  26 . Trigger  28  is mounted to gun body  26  and is configured to actuate a valve  40  to control spraying by spray gun  22 . Valve  40  is covered by tip mount  32  when tip mount  32  is disposed on gun body  26 . Fluid is output from valve  40  via outlet  41 . The fluid flows through tip mount  32 , to spray tip  34 , and out of spray tip  34  through tip piece  36 . 
     Tip mount  32  is attached to gun body  26  at mounting surface  42 . Tip mount  32  can be removably mounted to gun body  26 . For example, tip mount  32  can fit over a front end of gun body  26 , and tip mount  32  can include internal threading that interfaces with external threading on mounting surface  42  on the front end of gun body  26  to fix tip mount  32  to gun body  26 . Unthreading tip mount  32  from gun body  26  allows removal of tip mount  32  from gun body  26 . Spray tip  34  is mounted in a bore of tip mount  32 . Tip piece  36  is connected to spray tip  34 . Tip piece  36  can be formed from carbide or another metal. Tip piece  36  includes a narrow outlet that is configured to atomize the fluid exiting Tip piece  36  into a spray fan. Spray tip  34  is mounted in tip mount  32  such that spray tip  34  can be rotated 180 degrees to reverse the direction of fluid flow through tip piece  36 . Rotating spray tip  34  reverses the position of tip piece  36  so that fluid can flow into the outlet and out of an inlet of tip piece  36  to dislodge and flush any clogs that may develop in tip piece  36  during operation of airless sprayer system  10  (shown in  FIG. 1 ). While tip piece  36  in the embodiment of  FIGS. 2A and 2B  is shown in airless spray system  10  with spray gun  22 , tip piece  36  can also be included in a trigger-less auto-gun spray system as discussed further below with reference to  FIGS. 6A and 6B . 
       FIG. 3  is a cross-sectional view of spray tip  34  and tip piece  36  from the embodiment of  FIGS. 2A and 2B . As shown in  FIG. 3 , spray tip  34  further includes cylindrical body  44 , tip handle  46 , threaded retainer  48 , flat washer  50 , and plastic washer  52 . Cylindrical body  44  includes bore  54 . Tip handle  46  is connected to cylindrical body  44  and allows an operator to grip and turn cylindrical body  44  on center axis CA of cylindrical body  44 . Bore  54  extends transversely through cylindrical body  44  relative center axis CA. Tip piece  36  is received first into bore  54 , followed by plastic washer  52  and flat washer  50 . Threaded retainer  48  is inserted into bore  44  to lock tip piece  36  into position inside bore  54 . Bore  54  can include internal threads that engage external threads on threaded retainer  48 . In other embodiments, threaded retainer  48  can be replaced with a retaining member press-fitted into bore  54 . Threaded retainer  48  is provided with a hole to allow fluid to flow through threaded retainer  48 . 
       FIGS. 4A-4C  will be discussed concurrently.  FIGS. 4A-4C  provide various views of tip piece  36 .  FIG. 4A  is a perspective view of tip piece  36 ,  FIG. 4B  is a top view of tip piece  36 , and  FIG. 4C  is a side elevation view of tip piece  36 . As shown in  FIGS. 4A-4C , tip piece includes tip body  56 , axis AX, first end  58 , second end  60 , cylindrical portion  62 , domed portion  64 , conical portion  65 , and passage  66  with terminal end  68 . Tip piece  36  further includes nozzle  70 , first surface  71 , second surface  72 , and orifice  74 . Passage  66 , terminal end  68 , orifice  74 , and portions of nozzle  70  are shown in phantom in  FIG. 4A . 
     In the embodiment of  FIGS. 4A-4C , tip body  56  extends axially along axis AX from first end  58  to second end  60 . Cylindrical portion  62 , domed portion  64 , and conical portion  65  make up tip body  56 . Cylindrical portion  62  extends axially from first end  58  to conical portion  65 . Conical portion  65  extends axially from cylindrical portion  62  to domed portion  64 , and domed portion  64  extends axially from conical portion  65  to second end  60 . While the embodiment of tip body  56  in  FIGS. 4A-4C  comprises cylindrical portion  62 , domed portion  64 , and conical portion  65 , tip body  56  can include various different geometries and is not limited to the geometry of the embodiment shown in  FIGS. 4A-4C . For example, tip body  56  can include a cylindrical portion connected directly to a domed portion, or tip body  56  can include a cylindrical portion connected solely to a conical portion, or tip body  56  can be completely conical. In other embodiments, tip body  56  can be completely cylindrical. 
     Passage  66  extends axially inside tip body  56  from first end  58  to terminal end  68  between first end  58  and second end  60  of tip body  56 . At first end  58 , passage  66  forms a fluid inlet for tip piece  36 . In the embodiment of  FIG. 4A-4C , terminal end  68  of passage  66  is positioned within domed portion  64 . Terminal end  68  of passage  66  can be hemispherical or dome shaped. In alternative embodiments, terminal end  68  can be flat, cylindrical, parabolic, elliptical, conical, and/or other embodiments. 
     Nozzle  70  extends axially into tip body  56  from second end  60 . In the embodiment  FIGS. 4A-4C , nozzle  70  is disposed entirely on domed portion  64  of tip body  56 . Nozzle  70  extends axially from second end  60  and intersects terminal end  68  of passage  66  to form orifice  74 . As nozzle  70  extends toward passage  66  from second end  60 , nozzle  70  tapers and narrows. For example, as shown in  FIGS. 4A-4C , nozzle  70  can be wedge shaped with first surface  71  opposite second surface  72 . First surface  71  and second surface  72  converge toward one another as first surface  71  and second surface  72  each extends from second end  60  toward terminal end  68  of passage  66  and orifice  74 . As shown best in  FIG. 4C , first surface  71  and second surface  72  form a V-shaped side profile in nozzle  70 . 
     Orifice  74 , shown best in  FIG. 4A , fluidically connects nozzle  70  and passage  66 . Orifice  74  serves as the outlet for tip piece  36  and controls the spray pattern of the fluid exiting tip piece  36 . Since orifice  74  is formed between nozzle  70  and the domed or hemispherical shaped terminal end  68  of passage  66 , orifice  74  has an arch shape, with orifice  74  being widest at a peak of the arch shape, and narrowest at the ends of the arch shape, as shown in  FIGS. 4A and 4B . Nozzle  70  and orifice  74  can both be formed by forming first surface  71  and second surface  72  into second end  60  of tip body  56  until first surface  71  and second surface  72  both intersect terminal end  68  of passage  66  and thereby form the arch-shaped profile of orifice  74 . As discussed below with reference to  FIGS. 5A and 5B , a perimeter of orifice  74  is rounded to create a smooth and rounded interface between nozzle  70  and passage  66 . 
       FIGS. 5A and 5B  will be discussed concurrently. The embodiment shown in  FIGS. 5A and 5B  is taken directly from the embodiment of  FIGS. 4A and 4B .  FIG. 5A  is a cross-sectional view of nozzle  70 , orifice  74 , and terminal end  68  of passage  66  taken along line A-A from  FIG. 4B .  FIG. 5B  is an enlarged view of orifice  74  taken from circle C of  FIG. 5A . As shown in  FIGS. 5A and 5B , orifice  74  includes rounded interface  76  with a radius of curvature RC. Rounded interface  76  is formed on a perimeter of orifice  74  and extends between passage  66  and nozzle  70 . Rounded interface  76  connects first surface  71  and second surface  72  with the domed-shape surface of terminal end  68  of passage  66  and creates a relatively smooth transition across orifice  74  between passage  66  and nozzle  70 . For example, rounded interface  76  can have a radius of curvature in the range of 0.0005 inches (0.0127 millimeters) to 0.005 inches (0.1270 millimeters). The smooth transition created by rounded interface  76  at orifice  74  eliminates sharp edges between passage  66  and nozzle  70  that may be prone to erosion during use of tip piece  36 . Reducing erosion in tip piece  36  allows tip piece  36  to provide a more consistent spray pattern throughout the service life of tip piece  36 . 
     Rounded interface  76  can be formed after orifice  74  is formed by flowing a particle laden fluid through passage  66  and out of orifice  74 . In other embodiments, rounded interface  76  can be formed on orifice  74  via electrical discharge machining (EDM) or by laser cutting. To accommodate the formation of rounded interface  76 , orifice  74  can be formed first at a smaller dimension, then expanded in size as rounded interface  76  is formed on the perimeter of orifice  74 . Rounded interface  76  can also be formed at the same time as orifice  74 . For example, tip piece  36  can be manufactured by packing metal particles into a preform (such as tungsten carbide) and sintering the metal particles into tip piece  36 . In this example, rounded interface  76  and orifice  74  are both included in the shape of the preform prior to sintering. In another example, tip piece  36  can be formed via additive manufacturing, with rounded interface  76  and orifice  74  being formed in tip piece  36  during the additive manufacturing process. While tip piece  36  has been discussed above as being used in spray tip  34  for spray gun  22  (shown in  FIGS. 1-2B ), tip piece  36  with rounded interface  76  can be used spray tips for other systems, as discussed below with reference to  FIGS. 6A and 6B . 
       FIGS. 6A and 6B  will be discussed concurrently.  FIG. 6A  is a perspective view tip piece  36  assembled into flat spray tip  77 .  FIG. 6B  is a cross-section view of flat tip  77  taken along line B-B from  FIG. 6A . Flat spray tip  77  is used in automated spraying systems. As shown in  FIGS. 6A and 6B , flat spray tip  77  includes a body  78  extending axially between first end  80  and second end  82 . Body  78  of flat spray tip  77  includes a through-bore extending axially through body  78  and sized to receive tip piece  36 . Tip piece  36  is inserted into the through-bore of body  78  and is coaxial with body  78  of flat spray tip  77 . Washer  86  and fastener  85  are inserted into through-bore  78  after tip piece  36  to fasten tip piece  36  within flat spray tip  77 . Channel  84  is formed on second end  82  of flat spray tip  77  so that flat spray tip  77  does not restrict or interfere with nozzle  70  of tip piece  36 . 
       FIGS. 7-13  disclosure additional embodiments of tip piece  36 .  FIG. 7  is a perspective view of tip piece  36  with terminal end  68  of passage  66  having an elliptical shape. In the embodiment of  FIG. 7 , orifice  74  is formed in the elliptically-shaped terminal end  68  in similar fashion to the embodiment of  FIGS. 4A and 4B . Rounded interface  76  (shown in  FIGS. 5A and 5B ) can also be formed on the perimeter of orifice  74  in the embodiment of  FIG. 7  in similar manner as previously discussed. 
       FIG. 8  is a perspective view of tip piece  36  with terminal end  68  of passage  66  having a parabolic shape. In the embodiment of  FIG. 8 , orifice  74  is formed in the parabolically-shaped terminal end  68  in similar fashion to the embodiment of  FIGS. 4A and 4B . Rounded interface  76  (shown in  FIGS. 5A and 5B ) can also be formed on the perimeter of orifice  74  in the embodiment of  FIG. 8  in similar manner as previously discussed. 
       FIG. 9  is a perspective view of tip piece  36  with terminal end  68  of passage  66  having a conical shape. In the embodiment of  FIG. 9 , orifice  74  is formed in the conically-shaped terminal end  68  in similar fashion to the embodiment of  FIGS. 4A and 4B . Rounded interface  76  (shown in  FIGS. 5A and 5B ) can also be formed on the perimeter of orifice  74  in the embodiment of  FIG. 9  in similar manner as previously discussed. 
       FIG. 10  is a perspective view of tip piece  36  with terminal end  68  of passage  66  having a flat cylindrical shape. In the embodiment of  FIG. 10 , orifice  74  is formed in the flat-cylindrically-shaped terminal end  68  in similar fashion to the embodiment of  FIGS. 4A and 4B . Rounded interface  76  (shown in  FIGS. 5A and 5B ) can also be formed on the perimeter of orifice  74  in the embodiment of  FIG. 10  in similar manner as previously discussed. 
       FIG. 11  is a side elevation view of tip piece  36  with nozzle  70  arching into terminal end  68  of passage  66 . In the embodiment of  FIG. 11 , nozzle  70  can be formed by performing a plunge cut into second end  60  with a grinding wheel (not shown) until the grinding wheel cuts into terminal end  68  of passage  66  to form orifice  74 . 
       FIG. 12  is a perspective view of tip piece  36  with nozzle  70  a straight non-tapering profile. In the embodiment of  FIG. 12 , nozzle  70  extends axially into tip body  56  from second end  60 . Nozzle  70  is disposed entirely on domed portion  64  of tip body  56 . Nozzle  70  extends axially from second end  60  and intersects terminal end  68  of passage  66  to form orifice  74 . As nozzle  70  extends toward passage  66  from second end  60 , nozzle  70  maintains a constant spacing between first surface  71  and second surface  72 . Bottom surface  88  of nozzle  70  is formed between first surface  71  and second surface  72  and spaces first surface  71  apart from second surface  72 . First surface  71  and second surface  72  are parallel to each other. 
       FIG. 13  is a side elevation view of tip piece  36  with another embodiment of nozzle  70  that is different from the embodiments of  FIGS. 4A, 4B, and 12 . In the embodiment of  FIG. 13 , first surface  71  and second surface  72  form a V-shaped side profile in nozzle  70 . However, first surface  71  extends at a larger angle relative axis AX than second surface  72 , such that the V-shaped side profile of nozzle  70  is canted relative axis AX of tip piece  36 . 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.