US3851820A

US3851820A - Spray gun for producing a fan-like pattern

Info

Publication number: US3851820A
Application number: US00446720A
Authority: US
Inventors: T Hudson
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-02-28
Filing date: 1974-02-28
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03

Abstract

A spray gun is disclosed herein a plurality of spray nozzles are assembled in one unit, aligned with each other and placed relatively close together. The unit includes a rectangular body having a row of orifices formed in at least one of the longer sides thereof. These orifices communicate with a chamber formed by a groove carved in the adjacent long side of side of body. Spaced from each open end of the orifices is force-fitted a bead or small bushing. From the same side of the body containing the groove, a row of bores are drilled so that they communicate with respective ones of the orifices in the region between the bushing and the opening of the orifices. A plate is disposed against the groove of the body, and has formed thereon a pair of grooves each on opposite sides running the length thereof. The groove in the body is coupled to a pressurized air supply through suitable passageways in the body and the groove in the plate adjacent the body is coupled to a liquid supply, through other suitable passageways in the body. Another row of bores couples the groove on one side of the plate to the groove on the other side. An additional row of bores are drilled through the plate and each bore is aligned with a respective one of the bores in the body. Finally, in the plate, another row of bores is drilled from the side of the plate normal to the other bores therein and communicating with respective ones of the bores aligned with the bores in the body and communicating with the groove on the side of the plate, opposite the body. Suitable plugs are placed in the ends of these last mentioned bores. Another plurality of bores are drilled in the body opposite and aligned with respective ones of the other bores therein, with means in these other bores to control the opening of each one of the respective bores.

Description

United States atent I [191 Hudson Dec.3,1974

[76] Inventor: Truman 0. Hudson, 3205 Oakwood, Lynwood, Calif. 90262 22 Filed: Feb. 28, 1974 21 Appl. No.: 446,720

[52] US. Cl 239/407, 164/267, 239/417.5, 239/428.5, 239/434, 239/557, 239/562, 239/566 [51] Int. Cl. B22d 17/22 [58] Field of Search 239/186, 266, 268, 407,

444, 536, 548,550, 551,556, 557,562, 566, 581; 164/158, 267; 425/96, DIG. 50

Primary Examiner-Lloyd L. King Assistant Examiner-Andres Kashnikow Attorney, Agent, or FirmDominick Nardelli [57] ABSTRACT A spray gun is disclosed herein a plurality of spray nozzles are assembled in one unit, aligned with each other and placed relatively close together. The unit includes a rectangular body having a row of orifices formed in at least one of the longer sides thereof. These orifices communicate with a chamber formed by a groove carved in'the adjacent long side of side of body. Spaced from each open end of the orifices is force-fitted a bead or small bushing. From the same side of the body containing the groove, a row of bores are drilled so that'they communicate with respective ones of the orifices in the region between the bushing and the opening of the orifices. A plate is disposed against the groove of the body, and has formed thereon a pair of grooves each on opposite sides running the length thereof. The groove in the body is coupled to a pressurized air supply through suitable passageways in the body and the groove in the plate adjacent the body is coupled to a liquid supply, through other suitable passageways in the body. Another row of bores couples the groove on one side of the plate to the groove on the other side. An additional row of bores are drilled through the plate and each bore is aligned with a respective one of the bores in the body. Finally, in the plate, another row of bores is drilled from the side of the plate normal to the other bores therein and communicating with respective ones of the bores aligned with the bores in the body and com- I municating with the groove on the side of the plate,

opposite the body. Suitable plugs are placed in the ends of these last mentioned bores. Another plurality of bores are drilled in the body opposite and aligned with respective ones of the other bores therein, with means in these other bores to control the opening of each one of the respective bores.

11 Claims, 8 Drawing Figures FIELD OF THE INVENTION BACKGROUND OF THE INVENTION Single orifice spray heads for spray guns are simple to construct and can be made to produce many types of spray pattern. For example, to produce a round pattern, a round orifice is utilized; to produce a long rectangular or oval pattern, an oval orifice is utilized, etc. However, as everyone knows, the density of the liquid particles varies across the spray pattern wherein the density is greater at the geometric center. Therefore, in an elongated spray pattern, one finds a much wider variation of density than in the circular pattern. Normally this variation in density is of no consequence because the operator, being a skilled human, can handle and move the spray gun as he sees fit to produce a uniform coating. The problem arises when the spray gun is to move automatically. In such automatic operations the spray gun is made to move along a straight line, as any other motion provided thereto would be costly and still one cannot be assured the motions of a human operator are reproduced. This drawback is multiplied if the article to be coated uniformly is relatively large in relation to the spray pattern. Large articles to be coated with a liquid lubricant are usually found in 'die casting operations. In such operations the prior art teaches that the dies can be brush-coated. For-example, US. Pat. No. 3,248,762 teaches the useof a wide brush with bristles on opposite sides, wherein the brush automatically moved down after the dies open to apply lubricant on the faces of both dies. This procedure operates very well provided there are no deep recesses in the dies wherein the brush bristles cannot reach. However, everyone knows that a spray will penetrate mo st recesses and, as mentioned above, the-spray should have substantially uniform coating characteristics.

OBJECTS OF' THE INVENTION 7 An object of this invention is to provide a simple and rugged spray gun that produces an elongated spray pattern of substantially uniform density. I

Another object of this invention is to provide a spray gun with a plurality of aligned orifices wherein each orifice has the capability of atomizing and discharging liq-.

uid droplets.

Another object of this invention is to provide a spray gun for coating automatically die casting dies while producing a substantially uniform coating, thereby increasing cycle speed.

Another object of this invention is to provide a spray gun with a plurality of aligned orifices wherein the discharge range from each orifice can be independently adjusted while still allowing the spray gun to be started or stopped by one automatic trigger means.

Another object of this invention is to provide a multiorifice spray gun that is capable of blasting air along,

or a combination of air and liquid droplets.

These and other objects and features of advantage will become more apparent after studying the following description of the preferred embodiment of this invention, together with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side schematic elevation of a die casting machine incorporating an automatically controlled die lubricant applier, incorporating my novel spray gun.

FIG. 2 is a front elevation of the die lubricant applier of FIG. 1.

FIG. 3 is an exploded pictorial view of the spray gun shown in FIGS. 1 and 2.

FIG. 4 is an enlarged partial front elevation of the spray gun in partial section. I I

FIG. 5 is a view in partial section taken on line 55 in FIG. 4 in the direction of the arrows.

FIG. 6 is a view in partial section taken on line 6-6 of FIG. 4 in the direction of the arrows.

FIG. 7 is a view taken on line 7-7 in FIG/4. in the direction of the arrows.

FIG. 8 is an enlarged side elevation of the spray gun, in partial section.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1 wherein a standard die casting machine is shown schematically, the machine has a fixed die 11 suitably mounted to a fixed frame 12, and also has a moveable die 13 mounted on a ram 14. On

frame 12 is mounted a fixture 15, more clearly shown in FIG. 2. The fixture has a horizontal shelf 16 extending over' the space between the spread-apart dies 11 and 13. Spaced from and above shelf 16 is another shelf shown) are connected to the cylinder 18 to cause the 3 piston 19 to extend (lower) from and to retract (raise) into the cylinder 18. Up to now, the description has been of standard items and form no part of my invention except for my novel spray gun 21. Suitable controls lower my spray gun 21 automatically between the spaced dies, as taught for example in US. Pat. No. 3,248,762.

Referring to FIG. 3, my spray gun 21 has a rectangu-. lar body 25 to which are attached a pair of

tubes

23 and 24 disposed parallel to piston 19. The

tubes

23 and 24 have threaded ends and are threaded into suitable threaded holes in the body 25, as illustrated by threaded hole 26 (FIG. 4) to which tube 23 is threaded. Locking

nuts

27 and 28

lock tubes

23 and 24, respectively to body 21. The tubes 23 and 24'extend freely through suitable holes, not shown, in shelf 16. The top ends of

tubes

23 and 24 are coupled together by a plate 29 (FIG. 2), for. obvious reasons, and have

flexible lines

31 and 32 coupled, respectively, to

tubes

23 and 24.

' Suitable springs 33 are mounted on opposite sides of screws, as shown by screws 37 in FIG. 4, holds the body 25 and

plates

35 and 36 together.

The spray gun 21 has a plurality of spray orifices 41 formed in the body 25, and are disposed in two rows on opposite sides thereof with, for example, spray orifices 41 in a row. More or less spray orifices can be placed in a row and because of the teachings of my invention, they can be placed as close as one-half inch apart, but in the embodiment shown, the spray orifices are separated apart, for example, one and one-half inches. On each orifice 21 is ejected a fine mist of liquid droplets and air, and the combination is of substan' tially uniform characteristics. Liquid is fed to the body 25 through tubes 43 and 44 (FIG. 3) disposed concentric within

respective tubes

23 and 24. Air is fed into the body 25 through

tubes

23 and 24. The manner in which the air and liquid is ducted through the body 25 and passageway plates 35 to insure that a fine spray 'mist of liquid droplets is discharged through each spray orifice 41 will now be described.

Referring particularly to FIGS. 4, 5, 6, and 7, the details described for

concentric tubes

23 and 43 will hold for

concentric tubes

24 and 44. As seen in FIG. 4, tube 23 communicates with hole 26, which is formed by drilling a blind hole in body 25. On the bottom of hole 26 is formed a male thread 45, to which is attached tube 43 by a suitable tubing nut 46. Coaxial with hole 26 is drilled a smaller hole 47. On the opposite side of the body is counterbored a well 48, for reasons that will be explained hereinafter. On the face of the body 25, making contact with plate 35, are milled 3 aligned grooves, of which only two grooves, 49 and 50, are shown, in FIGS. 4 and 5. As shown therein, these grooves are separated in the region between the blind hole 26, for reasons that will become apparent hereinafter. These grooves are made to communicate with respective blind holes 26, by drilling suitable holes 51. Now air can enter the grooves from hole 26. As shown in FIG. 8, the spray orifices41' are holes drilled into thebody 25 to communicate with

respective grooves

49 or 50.

Within orifices 41 are pressed suitable beads or small bushings 54, to form a constriction therein for reasons that will become apparent. Each bushing 54 is spaced a predetermined distance from the outer ends, and these distances are preferably equal to each other. Because'of the Venturi effect produced as the air leaves 5 bushing 54, a drop in pressure will be observed in the regions immediately following the bushing.

l have devised an arrangement of ducts in the spray head 21 to insure that a substantially equal quantity of liquid flows to each of these respective low-pressure regions. From the same side of the body 25 wherein

grooves

49 and 50 are formed, holes 56 are drilled to communicate with the respective orifice 41 in this lowpressure region, i.e., between the bushing and the outer edge. Now, referring to FIGS. 6 and 7, holes 57 are drilled through plate 35 and each hole 57 is aligned with the respective hole 56 in the body. Liquid is supplied to

holes

56 and 57 from

tubes

43 or 44, as follows: Plate 35 has a pair of bores, such as bore 58, drilled therethrough and in alignment with counter-bored well 48. On the face of the plate 35, adjacent to body 25, are

milled a pair of parallel grooves 61, each disposed and spaced from the respective row of holes 57, as shown in FIG. 7. Another groove 62 is formed that extends from hole 58 to the middle of one groove 61 and in a similar manner a partially shown groove 63 is formed to extend from the other hole, not shown, similar to hole 58 to the middle of the other groove 61.

As shown in FIG. 6, on the opposite side of plate 35 are milled another pair of parallel grooves 65, spaced slightly inboard of the pair of grooves 61 on the opposite side. One groove 61 is made to communicate with one respective groove 65 by drilling a plurality of holes 66 through the plate. These holes 66 are offset with re spect to grooves 61 and also with respect to groove 65, for reasons that will be explained hereinafter. The other groove 61 is made to communicate with the other respective groove 65, also by drilling a plurality of holes 67 through plate 35. These holes 67 are also offset with respect to both

grooves

61 and 65. As shown in FIG. 8, each hole 57 is made to communicate with respective groove 65 by drilling a hole 69 from the side of plate 35, so that hole 69 is spaced from the face of plate 35 for reasons that will be explained. The portion of each hole 69, between hole 57 and the side of the plate, is suitably plugged with a dowel 70.

The spray gun operates as follows: When piston 18 is programmed to lower the gun 21 between the spray dies 11 and 13, a limit switch turns on an air valve (both not shown) and pressurized air enters

tubes

23 and 24, passes through holes 51 into

grooves

49 and 50, and out of orifices 41. As air exits each bushing 54, liquid is drawn up holes 56 and the liquid is atomized. The liquid arrives to each hole 56 by

respective holes

57 and 69, grooves 65, holes 67,

grooves

61 and 62, and aligned

holes

58, 48, and 47. Within the liquid passageways, and in particular each hole 48, there is provided a one-way valve in a form of a ball 72 and spring 73. This prevents liquid from dripping after the air supply is shut off. By allowing the liquid from one tube 43 to feed liquid to only the orifices on one side, and the liquid from the other tube 44 to feed liquid to only the orifices on the other side, different liquids can be used on respective sides. Also, one side can be shut off while the other side is usable, Groove 62 communicates with the center of one groove 61, and insures equal amounts of liquid going into both ends thereof. The

holes

66 and 67, being offset, insures a more equal distribution of liquid in respective grooves 65, which, in turn, insures a more even distribution at each orifice.

Although all the above precautions have been taken to insure a substantially uniform spray between each orifice, due to inherent manufacturing tolerances, the spray, for some applications, is not sufficiently uniform. I have devised a means to adjust the rate ofliquid drop lets exiting each orifice 41 that does not require substantially clean liquid. This system only requires the liquid, free of dirt particles above a given size, as determined by the cross-section of the respective passageways already described, for the liquid to flow through. Any reduced restrictions in these liquid passageways, of course, requires cleaner fluids. The means for adjusting the spray includes a plurality of bores formed in a body 25, such as bore 74, as shown in FIG. 8, each of which bores is aligned substantially with a respective hole 56. These bores 74 communicate also with the low-pressure regions immediately following the bushing 54. Each bore 74 is formed with a shoulder 75 by drilling a counterbore 76 and providing therein threads. Within the threaded counterbore 76 is screwed a needle-valve 77 whose pointed end seats against the shoulder. Another bore 78 is drilled in body 75 to communicate with bore 76, as shown in FIG. 8.

A similar means is provided for each orifice 41, thus by simply turning the needle-valve 77, the amount of air entering each orifice 41 through respective bore 74 is controllable. Since this air is controllable, the liquid entering the orifices 41 from the holes 56 below is also being controlled, and if a dust particle does enter the system, the means is self-cleaning by simply opening the needle-valve 77 and resetting it.

Having described the preferred embodiment of my invention, one skilled in the art, after studying the above disclosure, can devise other embodiments and still come within the spirit of my invention. Therefore, my invention is not to be considered as limited to the described embodiment, but includes all embodiments coming within the scope of the claims.

I claim:

1. A spray gun comprising:

a body having a plurality of orifices formed therein;

said body having first duct means communicating with each orifice;

first means for supplying pressurized air to said first duct means-so that air passes through each of said orifices and exists said body;

a bushing having a central aperture disposed within each one of said orifices, spaced inward from the opening thereof so that a Venturi effect is produced by the air passing therethrough;

said body having a second duct means communicating with each orifice in the region between said bushing and the opening thereof;

second means for supplying liquid to-said second duct means so that the liquid therein mixes with the air passing through each of said bushings in each of said orifices.

2. The spray gun of claim 1 wherein:

said body has a plurality of third duct means connecting the respective regions between said bushings and the opening of said orifices to the atmosphere; and

valve means in each of said third duct'means to regulate the flow of atmospheric air to'each one of said respective regions.

3.The spray gun of claim 1 wherein:

said body is shaped as an elongated, rectangular block, and saidorifices are disposed aligned on at least one of the elongated sides thereof;

said first duct means includes a first groove formed in another one of the elongated sides of said body, adjacent the side with said orifices, and said orifices extending between said groove and the outside of said body;

said second duct means comprising a passageway plate disposed against the side of said body having said first groove;

said passageway plate having a second groove extending the length thereof;

said body having a plurality of holes, each disposed at right angles to said respective orifices and communicating with said second groove.

4. The spray gun of claim 3 wherein:

said passageway plate has a third groove extending the length thereof, and disposed on the opposite side from said second groove;

said passageway plate has a plurality of first holes drilled therethrough, to communicate with said second groove and said third groove;

said third groove is disposed against said body;

said passageway plate has a plurality of second holes drilled therethrough, and aligned with respective ones of said holes in said body;

said passageway plate has a plurality of holes formed between said second groove'and aligned with respective ones of said second holes disposed at right angles thereto.

5. The spray gun of claim 4 wherein:

said body has also a second plurality of aligned orifices disposed opposite said first mentioned orifices;

said second plurality of orifices also extending between said groove and said body, and the outside thereof;

said passageway plate has a fourth groove formed on F the same side of said second groove, and disposed substantially parallel thereto;

said body has another plurality of holes, each disposed at right angles to respective ones-of said second plurality of orifices and communicating with said fourth groove.

6. The spray gun of claim 5 wherein:

said passageway plate has a fifth groove formed on the same side of said third groove, and disposed substantially parallel thereto;

said passageway plate has a plurality of holes drilled therethrough to connect said fourth groove to said fifth groove;

said passageway plate has a plurality of third holes drilled therethrough and aligned with the respective ones of said other plurality of holes in said body, which holes communicate with said second plurality of orifices;

said passageway plate has a plurality of holes formed between said fourth groove and with respective ones of said holes in communication with said second orifices.

7. The spray gun of claim 5 wherein:

said body has a plurality of third duct means communicating with respective regions between said bush- "ing and the opening of said orifices, and communicating with the atmosphere; and valve means in each one of said duct means to regulate the flow of atmospheric air to each one of said respective regions.

8. A multi-orifice spray gun' comprising:

a body havinga plurality of orifices formed therein and first duct means for supplying pressurized air to each of said orifices;

each of said orifices being shaped so that a Venturi effect is produced by the air passing therethrough;

second duct means carried by said body;

said second duct means having a main duct and a plurality of minor ducts branching therefrom;

means for supplying liquid into said main duct, each of said minor ducts terminating and communicating with a respective orifice in the lower pressure region as produced by the Venturi effect.

9. The gun of claim 8 wherein:

said body is shaped as an elongated, rectangular block, and said orifices are disposed in a line on at least one of the elongated sides thereof.

10. The gun of claim 8 wherein:

each of said orifices includes a cylindrical bore having a larger diameter at its exterior opening, a smaller diameter spaced inward from the opening thereof. a

11. The gun of claim 10 wherein:

a bushing is disposed in each of said orifices to form the smaller diameter thereof.

Claims

1. A spray gun comprising: a body having a plurality of orifices formed therein; said body having first duct means communicating with each orifice; first means for supplying pressurized air to said first duct means so that air passes through each of said orifices and exists said body; a bushing having a central aperture disposed within each one of said orifices, spaced inward from the opening thereof so that a Venturi effect is produced by the air passing therethrough; said body having a second duct means communicating with each orifice in the region between said bushing and the opening thereof; second means for supplying liquid to said second duct means so that the liquid therein mixes with the air passing through each of said bushings in each of said orifices.

2. The spray gun of claim 1 wherein: said body has a plurality of third duct means connecting the respective regions between said bushings and the opening of said orifices to the atmosphere; and valve means in each of said third duct means to regulate the flow of atmospheric air to each one of said respective regions.

3. The spray gun of claim 1 wherein: said body is shaped as an elongated, rectangular block, and said orifices are disposed aligned on at least one of the elongated sides thereof; said first duct means includes a first groove formed in another one of the elongated sides of said body, adjacent the side with said orifices, and said orifices extending between said groove and the outside of said body; said second duct means comprising a passageway plate disposed against the side of said body having said first groove; said passageway plate having a second groove extending the length thereof; said body having a plurality of holes, each disposed at right angles to said respective orifices and communicating with said second groove.

4. The spray gun of claim 3 wherein: said passageway plate has a third groove extending the length thereof, and disposed on the opposite side from said second groove; said passageway plate has a plurality of first holes drilled therethrough, to communicate with said second groove and said third groove; said third groove is disposed against said body; said passageway plate has a plurality of second holes drilled therethrough, and aligned with respective ones of said holes in said body; said passageway plate has a plurality of holes formed between said second groove and aligned with respective ones of said second holes disposed at right angles thereto.

5. The spray gun of claim 4 wherein: said body has also a second plurality of aligned orifices disposed opposite said first mentioned orifices; said second plurality of orifices also extending between said groove and said body, and the outside thereof; said passageway plate has a fourth groove formed on the same side of said second groove, and disposed substantially parallel thereto; said body has another plurality of holes, each disposed at right angles to respective ones of saiD second plurality of orifices and communicating with said fourth groove.

6. The spray gun of claim 5 wherein: said passageway plate has a fifth groove formed on the same side of said third groove, and disposed substantially parallel thereto; said passageway plate has a plurality of holes drilled therethrough to connect said fourth groove to said fifth groove; said passageway plate has a plurality of third holes drilled therethrough and aligned with the respective ones of said other plurality of holes in said body, which holes communicate with said second plurality of orifices; said passageway plate has a plurality of holes formed between said fourth groove and with respective ones of said holes in communication with said second orifices.

7. The spray gun of claim 5 wherein: said body has a plurality of third duct means communicating with respective regions between said bushing and the opening of said orifices, and communicating with the atmosphere; and valve means in each one of said duct means to regulate the flow of atmospheric air to each one of said respective regions.

8. A multi-orifice spray gun comprising: a body having a plurality of orifices formed therein and first duct means for supplying pressurized air to each of said orifices; each of said orifices being shaped so that a Venturi effect is produced by the air passing therethrough; second duct means carried by said body; said second duct means having a main duct and a plurality of minor ducts branching therefrom; means for supplying liquid into said main duct, each of said minor ducts terminating and communicating with a respective orifice in the lower pressure region as produced by the Venturi effect.

9. The gun of claim 8 wherein: said body is shaped as an elongated, rectangular block, and said orifices are disposed in a line on at least one of the elongated sides thereof.

10. The gun of claim 8 wherein: each of said orifices includes a cylindrical bore having a larger diameter at its exterior opening, a smaller diameter spaced inward from the opening thereof.

11. The gun of claim 10 wherein: a bushing is disposed in each of said orifices to form the smaller diameter thereof.