Patent Publication Number: US-6213410-B1

Title: Gravity-fed spray gun assembly using friction-induced locking element

Description:
This application is a Continuation-In-Part of application Ser. No. 09/058,708 filed on Apr. 10, 1998 and is now U.S. Pat. No. 6,012,651. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to gravity-fed spray guns and more particularly to an apparatus for providing enhanced spray capabilities for such gravity-fed spray guns. 
     2. Description of the Related Art 
     Spray guns are commonly used to apply paint, primer or any other liquid substance to a surface. The most common handicap a painter encounters, regardless of whether he is using a gravity or suction spray gun is the inability to go low enough to paint upward. For example, in the auto body industry, the rocker panel (below the door line) is seldom painted on the lower surfaces. The reason for this deficiency is that the car is too low to the ground and the spray gun assembly is too long to provide for proper access. A gravity-fed spray gun, excluding regulator and hose connection is generally 11 to 13 inches long. A suction spray gun is generally 13 inches long excluding regulator and hose connection. The spray gun cannot be tilted sideways without the possibility of spilling paint from the cup or having the smooth flow of paint to the gun being interrupted. 
     Similar problems exist in the paint industry, generally. For example, in spraying overhead, the painter cannot always conveniently tilt the spray at the proper angle for proper application of the paint, or other surface treatments. 
     As one solution to these problems, the present applicant has invented an improved spray gun, disclosed and claimed in U.S. Pat. No. 5,803,360 entitled “Apparatus for Providing Enhanced Spray Gun Capabilities for a Gravity-Fed Spray Gun.” That invention utilizes a swivel joint assembly that provides rotation of the fluid cup along a fluid cup offset axis, which is perpendicular to the fluid cup axis. After rotation of the fluid cup relative to the spray gun body the nozzle has to be rotated to obtain the previous spray pattern. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore a principal object of the present invention to provide efficient use of a gravity-fed spray gun for surfaces not easily accessible, such as low surfaces and overhead surfaces. 
     It is another object to obviate the requirement of rotating the nozzle assembly when the spray gun body is rotated relative to the fluid cup and still maintain the desired spray pattern orientation while maintaining the fluid cup in a substantially vertical position. 
     These and other objects are achieved by the present invention which is a gravity-fed spray gun assembly of the type having a nozzle assembly, a spray gun body assembly and a nozzle nut for adjusting the relative angular orientation of the nozzle assembly relative to the spray gun body assembly. The gravity-fed spray gun assembly includes a spray gun body assembly, a fluid delivery assembly and a friction-induced locking element. The fluid delivery assembly includes a rotatable element, a nozzle assembly and a fluid cup. The rotatable element is rotatively connected to the spray gun body assembly. The nozzle assembly is securely attached to the rotatable element. The nozzle assembly is maintained unable to rotate relative to the rotatable element unless a nozzle nut is adjusted. The nozzle assembly has a nozzle opening defining a nozzle axis. The rotatable element is rotatable about the nozzle axis. The fluid cup is securely attached to the rotatable element. The friction-induced locking element utilizes a predetermined preload that cooperatively engages the spray gun body assembly and the fluid delivery assembly to securely maintain the spray gun body assembly relative to the fluid delivery assembly at the desired relative angular orientation. The present invention obviates any requirement for loosening the nozzle nut to rotate the nozzle assembly relative to the spray gun body assembly when the spray gun body assembly is rotated relative to the fluid cup. 
     Other objects, advantages, and novel features will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side perspective view of a first embodiment of the gravity-fed spray gun assembly of the present invention. 
     FIG. 2 is a side perspective view of the first embodiment having a cut-away portion to reveal internal parts thereof. 
     FIG. 3 is an enlarged view, partially cut-away, of a portion of the first embodiment of the present invention. 
     FIG. 4 is a view taken along line  4 — 4  of FIG.  3 . 
     FIG. 5 is a front view of the first embodiment of the spray gun assembly of the present invention. 
     FIG. 6 is another front view showing the spray gun body assembly rotated clockwise ninety degrees, with the fluid cup and nozzle assembly remaining in the same position. 
     FIG. 7 is another front view showing the gun body rotated counter-clockwise ninety degrees with the fluid cup and nozzle assembly remaining in the same position. 
     FIG. 8 is a side perspective view of a second embodiment of the gravity-fed spray gun assembly of the present invention. 
     FIG. 9 is a side perspective view of the second embodiment having a cut-away portion to reveal internal parts thereof. 
     FIG. 10 is an exploded side view of the hollow bolt, hollow fastener, and flexible washer of the second embodiment. 
    
    
     The same reference characters designate the same parts or elements throughout the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and the characters of reference marked thereon, FIGS. 1 and 2 illustrate a preferred embodiment of the present invention, designated generally as  10 . The gravity fed spray gun assembly includes a spray gun body assembly  12 , a fluid delivery assembly  14  and a locking element  17 . The fluid delivery assembly  14  includes a rotatable element  16 , a nozzle assembly  18  and a fluid cup  20 . The rotatable element  16  is rotatively connected to the spray gun body assembly  12 , as will be explained in detail below. The nozzle assembly  18  is securely attached to the rotatable element  16  during use. The nozzle assembly  18  is unable to rotate relative to the rotatable element  16  unless the nozzle nut  22  is adjusted. The nozzle assembly  18  has a nozzle opening  24  defining a nozzle axis  26 . The rotatable element  16  is rotatable about the nozzle axis  26 . The fluid cup  20  is secured to the rotatable element  16 . Fluid cup  20  is screwed into position and is therefore unable to rotate relative to the rotatable element during use. 
     Referring now to FIG. 3 an enlarged view of salient portions of the spray gun body assembly  12  and fluid delivery assembly  14  are illustrated. The spray gun body assembly  12  includes a spray gun body  28 , which retains a hollow fastener  30  therewithin. The hollow fastener may comprise for example, a hollow nut. The rotatable element  16  retains a hollow bolt  32  therewithin. The hollow fastener  30  and the hollow bolt  32  are threadibly engaged, as shown at location  34 . Inside this resulting assembly is positioned a Teflon™ needle seal  36 . Also retained within this assembly is a biasing spring  38  for the seal  36 . The seal  36  prevents fluid seepage adjacent to the needle  40 . A bushing  42  is pressed into the rotatable element  16  to serve as a fixing guide. A spring washer  44  is provided to ensure a tight fit. 
     The locking element  17  is positioned within a slot  46  in the spray gun body assembly  12 . A spring  48  pushes the locking element  17  into one of a plurality of circumferentially spaced indents  50  (see FIG.  4 ). The indents  50  are formed within the rotatable element  16 . 
     Referring now to FIGS. 5-7, the versatility of the present invention is illustrated. In FIG. 5, the fluid cup  20  and the spray gun body assembly  12  are both in vertical positions. The nozzle assembly  18  is positioned for the desired pattern. 
     Referring now to FIG. 6, the spray gun body assembly  12  is rotated to 90° clockwise. The fluid cup  20  remains vertical. However, the nozzle assembly  18  remains in the same position as that shown in FIG.  5 . By being able to maintain the fluid cup  20  in a vertical position and concomitantly maintaining the nozzle assembly  18  in this desired position while being able to rotate the spray gun body assembly  12  to a comfortable desired angle, many painting and other spraying applications are realizable, which otherwise cannot be provided. For example, currently, painting of the rocker panels underneath the doors of the automobile, the wheel housings, wheel openings, trunks, engine base are all problematic because paint often drips out of the fluid cup or off of the fluid cup; or, the fluid cannot get to the nozzle assembly  18  because of the undesired orientation of the fluid cup  20 . The present invention alleviates these problems, allowing the fluid cup  20  to remain in a vertical position. Furthermore, any requirement for loosening the nozzle nut  22  to rotate the nozzle assembly  18  relative to the spray gun body assembly  12 , when the spray gun body assembly  12  is rotated relative to the fluid cup  20 , is obviated. 
     FIG. 7 illustrates that the spray gun body assembly  12  can be rotated in the opposite direction but achieve the same desired effect. 
     Referring now to FIGS. 8-10 another embodiment of the gravity-fed spray gun assembly of the present invention is illustrated, designated generally as  60 . In this embodiment, the locking element  17  of the previous embodiment has been eliminated and instead a friction-induced locking element utilizing a predetermined preload cooperatively engages the spray gun body assembly and the fluid delivery assembly to securely maintain said spray gun body assembly relative to said fluid delivery assembly at the desired relative angular orientation. This embodiment has less parts and is easier to manufacture than the first embodiment. 
     A hollow bolt  32 , as in the previous embodiment, is retained within the rotatable element  16 . A hollow fastener  30 , also as in the previous embodiment, is retained within the spray gun body assembly  12 . The hollow fastener  30  and the hollow bolt  32  are threadibly engaged. A flexible washer  62  is cooperatively engaged with the hollow fastener  30 , the hollow bolt  32  and a portion  64  of the spray gun body assembly  12  for providing the predetermined preload between the spray gun body assembly  12  and rotatable element  16 . This achieves a predetermined friction-induced lock. A bushing  66  is preferably provided for reducing wear. 
     Although the advantages of this invention have been described in particular with respect to the automobile industry it is understood that it can be utilized in many other industries, for example the furniture industry. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.