US 3252657 A
Description (OCR text may contain errors)
y 4, 1966 D. D. WINEGAR 3,252,657
SPRAY GUN AIR GAP Filed May 5, 1965 INVENTOR. DON D. WINE 64R 06AM flati j arromver United States Patent 3,252,657 SPRAY GUN ARR CAP Don D. Winegar, 3255 Bean St., San Diego, Calif. Filed May 3, 1965, Ser. No. 452,803 Claims. (Cl. 239-296) This application is a continuation-in-part of my pending application, Serial No. 255,841, filed February 4, 1963, now abandoned, bearing the same title.
The present invention relates to an air supply cap for a spray gun, the latter having a nozzle, and more particularly to a cap for spray guns for paint or similar material.
The invention has for its objects to provide a spray gun air cap that provides means for obtaining a greater and more uniform concentration of paint on the surface to which the paint is applied; a more uniformly distributed application, together with minimization of unwanted spraying; improved range and increased distance that paint can be sprayed, thereby saving time and labor in the shifting of ladders and scaffolding; and confining the form of the pattern of the spray of paint so that the area thereof has a clearly defined perimeter, and whereby spraying of the paint upon a surface can be maintained to an edge or mark, without material overspraying.
The air supply cap of the present invention includes a main body. This body is provided with a central passage for receiving a nozzle for fluid, such as paint. This passage is axially aligned with the flow of fluid emanating from the nozzle. The main body is also provided with at least two conduit means. The outlets of these conduit means are disposed downstreamwise of the aforementioned central passage, spread downstreamwise, and are disposed a substantially equal distance from the axis of the central passage and the stream emanating from the nozzle throughout the spreading width thereof.
Other features and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein preferred embodiments of the invention are illustrated.
In the drawing:
FIG. 1 is a perspective view of the cap.
FIG. 2 is a top plan view of the cap.
FIG. 3 is a cross-sectional view taken substantially along line 33 of FIG. 2 and including the outlet end or nozzle of the spray gun.
FIG. 4 is a fragmentary sectional view taken along the line 4-4 of FIG. 3.
FIG. 5 is a perspective view diagrammatically illustrating the formation of the air envelope around the sprayed fluid.
FIG. 6 is a diagrammatic view illustrating the relationship of the sprayed fluid and air envelope at the time they reach the surface being sprayed.
FIG. 7 is a fragmentary perspective view of a modified form of cap.
FIG. 8 is a fragmentary view in section of another modified form of cap.
FIG. 9-is a sectional view taken along line 99 of FIG. 8.
Referring more in detail to the drawing, the air cap is shown generally at as a main body secured to the spray head of an air gun (not shown) in the usual manner, as by a rotatable coupling collar 22. The main body 20 is provided with a central orifice 24 which is axially aligned with a nozzle 26 leading from a container of the fluid, such as paint, which is to be sprayed. This orifice 24 is somewhat larger in diameter than the outer diameter of the tip of the nozzle 26, forming an annular passage around said tip.
The main body 20 also includes a pair of lugs 28 and 30 which are readilydisposed with respect to the axis of the nozzle 26 and orifice 24 and are diametrically disposed on opposite sides of the orifice 24. Inner surfaces 32 on these lugs 28 and 30 flare outwardly downstreamwise, and each terminates at its outer end in a floor 34. In the embodiment shown in FIGS. 1 to 4, inclusive, deflectors 36 extend from the lugs 28 and 30 downstreamwise of the floor 34. The inner surfaces 38 of these deflectors 36 may be straight, as shown, or may be substantially arcuate in shape with the axis thereof the same as the axis of the nozzle 26 and orifice 24.
Each of the lugs 28 and 30 is provided with a conduit 40 which extends from the interior of the cap downstreamwise, and the end 44 thereof being in open communication with the inlets of conduit means 42 which spread downstreamwise and are disposed substantially equally distant from the axis of the stream of fluid emanating from the nozzle, i.e. also from the axis of the orifice 24. In the embodiment shown in FIGS. 1 to 4, each of the plurality of conduit means 42 includes a set of branch orifices comprising, preferably, a central orifice 44 and diverging orifices 46 and 48. As viewed in FIG. 4, showing one of the conduit means 42, orifice 46 diverges downstreamwise and to the left of orifice 44, and orifice 48 diverges downstreamwise and to the right of central orifice 44. Therefore, the inlet ends of these orifices join together upstreamwise from the outlets 50 thereof. Air under pressure, emanating from the cap, is spread fanwise due to the divergence of the orifices 44, 46 and 48.
It is desirable to provide the deflectors 36 beyond the downstream ends 50. These deflectors are provided with grooves 52, 54 and 56 which extend along the angles, respectively, of the orifices 44, and 46 and 48. Such deflectors are omitted from the embodiment shown in FIG. 7.
Said grooves 52, 54 and 56 may be offset radially outwardly of the respective orifices 44, 46 and 48 which form downstream diverging extensions, as indicated best in FIGS. 1, 2 and 3. If desired, each orifice 44, 46 and 48, and the groove extension of each, may be formed coaxially, i.e., the grooves 52, 54 and 56 are not radially displaced with relation to the orifices 44, 46 and 48.
Referring now to the embodiment shown in FIGS. 8 and 9, the conduit means is shown as a narrow fan-shaped slot 144 which spreads downstreamwise and is disposed substantially equidistant from the axis of the fluid emanating from the nozzle throughout the width and length thereof.
Each of the lugs 28 and 30 is provided with an orifice 58, the inlet of which communicates with the passage 50. These orifices 58 are disposed for directing air transversely of and into the stream of fluid emanating from the nozzle 26. As shown in FIG. 3, the outlet ends of these orifices 58lie downstrearnwise of the end of the nozzle 26 and upstreamwise of the outlets 50 of the orifices 44, 46 and 48. I
The main body 20 has a floor60 that is provided with a pair of orifices 62, one on each side of the axial orifice 24 and preferably upstrearnwise of the outlet of the passage 24. This orifice 24 is disposed intermediate the orifices 62 and the outlets of the orifices 58.
Referring to FIGS. 5 and 6, column 64 represents the paint and air mixture formed by the paint and air, respectively emanating from the nozzle 26 and the orifice 24; columns 66 and 68 represent the air emanating from the orifices 62; and columns 70 and 72 represent the air emanating from the orifices 58. The mixture of paint and air formed by the paint emanating from column 64 and the air emanating fromcolumns 66 and 68, is represented by the numeral 74. This mixture is in a flattened pattern, as shown. Air streams emanating downstream from the orifices 44, 46 and 48 are indicated by columns 76 and 78, the former being developed by the conduit means in the lugs 28, while the area of air shown by column 78 is developed by the latter conduit means in the lug 30. dui't means 44 spreads parallelly of the flattened stream of mixture 74, whereby the air emanating therefrom spreads parallelly of the stream 74 to provide the envelope 80.
It will be observed that these streams of air 76 and 78 gradually and finally provide an envelope indicated by the numeral 80.
Also, the air envelope 80 confines all of the paint particles within the column 74 to prevent any over-spray. The air spray columns 76 and 78 on opposite sides of the paint mixture 74 tend to compress the mixture to oval shape, as is indicated by the numeral 82. Some of the air of the envelope mixes with the paint to help produce better atomization of the latter.
The spread of the air spray columns 76 and 78 is dependent on the angular divergence of the orifices 46 and 48, together with groove extensions 54 and 56. Due to .this spreading of the air spray, the columns 76 and 78 join to form the envelope 80 substantially closer to the nozzle than if the described conduit means had been omitted. The length of the envelope 80 is, therefore, increased, as maintained by the inward pressure on the paint mixture 74. Also, by virtue of the present invention, a greater concentration of paint on the work is accomplished. The paint is more evenly distributed, and the unwanted spraying is materially minimized. Al so, by virtue of the present invention, the range and distance at which paint can be sprayed is increased, thus reducing the number of times that a ladder has to be moved in order to do a given job. In addition, the area of the paint is clearly confined, whereby spraying of the paint upon a surface can be maintained to an edge which is not to be sprayed, i.e., overspraying of the paint is minimized.
While the forms of embodiment herein shown and described constitute preferred forms, it is to be understood that other forms may be adopted which fall within the scope of the claims that follow.
1. An air supply cap for a spray gun for fluid, which gun is provided with a nozzle for fluid, said cap being provided with a main body, said body having:
(a) a central air-passing orifice through which said nozzle extends, said orifice being coaxial with the nozzle and the flow or fluid therefrom;
(b) a plurality of air-passing orifices in said body disposed on opposite sides of the axis of the central passage, said orifices each having an outlet disposed downstreamwise of the central orifice, the walls of the main body forming said orifices being inclined 'toward the axis of the central passage downstreamwise for directing air from opposite sides against the fluid mixture emanating from the central orifice and the nozzle to provide a flattened pattern of said emanated fluid mixture; and
It will be observed that the con- (c) two air conduit means 'for directing air to form an envelope of air longitudinally about the flattened pattern of fluid mixture, one of said conduit means lying substantially radially outwardly of one of said orifices and the other of said conduit means lying substantially radially outwardly of the other of said orifices, each of said conduit means including angularly spread orifices that extend downstream substantially parallelly of the flattened pattern and spreading to term said envelope and have outlets disposed downstreamwise of the outlets of the orifices.
2. In a spray gun air cap having an axial orifice for a paint nozzle,
(a) a body having an air-receiving inner area opening into said orifice for mixture with paint from said nozzle to form a downstream column of paint mixture,
('b) said body having diametrally disposed orifices open to saidinner area of the body and disposed to direct air from said area toward the mentioned paint mixture column to flatten the same, and
(c) conduit means radially outward of said diametrallydisposed orifices,
(d) each said means comprising a conduit open to said inner body area and extending downstreamward, a plurality of diverging orifices extending from the downstream end of said conduit, and a groove extending downstream fromv each of said diverging orifices and, respectively, along the lines thereof,
(e) said diverging grooves of the conduit means forming spreading columns of air on opposite sides of the flattened column of paint mixture and then joining to encircle and press upon said paint mixture column.
3. In a spray gun air cap according to claim 2,
(a) said body being provided with diametrically disposed extensions beyond the downstream ends of the diverging orifices,
(b) the mentioned grooves being formed in 'the inner opposed faces of said extensions.
4. In a spray gun air cap according to claim 3, the grooves being radially outwardly offset from the. respective orifices from which they extend.
5. In a spray gun air cap according to claim 4, asecond pair of diametrally disposed orifices open to the inner area of the body and located inwardly toward the axial orifice of the first-mentioned diametrally disposed orifices, said second pair of orifices being disposed to direct air from said inner area to intersect the air being directed to flatten the paint mixture.
References Cited by the Examiner UNITED STATES PATENTS 2,049,700 8/1936 Gustaisson 239-296 2,070,696 2/ 1937 Tracy 239-296 2,587,993 3/ 1952 Gray 239-296 M. HENSON WOOD, JR., Primary Examiner.