US2152767A

US2152767A - Spray gun

Info

Publication number: US2152767A
Application number: US99712A
Authority: US
Inventors: Mcknight George
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-09-08
Filing date: 1936-09-08
Publication date: 1939-04-04
Anticipated expiration: 1956-04-04

Description

April 4, 1939. McKNlGHT 2,152,767

SPRAY GUN Filed sept. s, 195e Zigi-' 50g?" Q@ i m e Patented pr. 4, 1939 UNITED STATES PAT-ENT oFFicE SBRAY GUN George McKnight, Chicago,V Ill.

.Application Septemberrv 8, 1936, Serial No.- 99,712

2 Claims.

This 4invention relates to spray guns in which the material is atomized by Ameans of compressed air and is ejectedf from a tubular nczzle'and thereafter converted into a relativelyl flatspray.

5 In spray guns of 4this class, the material isprojected from-the tubular tip of the nozzle, around which nozzle air` also issues under such pressure that it commingles with the material tofor-m a stream of partly atomized material of "circular formation. vThis stream is then subjected to two opposing` jets of air which fiatten the stream and completes the atomization. The two air/jets cooperate with the air" which is issued around .the nozzle-tip to carry the atomized spraywith considerable velocity against an .object to besprayed.

it is an object of this invention to provide' a nozzle which has openings arranged therearound that are directed at an angle tothe axial center of the nozzle and through which-openings, the

air is forced in a circulating manner around the nozzle to effect a whirling even flow of air around the material as it is ejected from the nozzle tip.

A further Voloject is to provide adjustable means for regulating the fioW of airto'the two opposed jets for regulatingthe pressure'of air against the circular formation of material todetermine the degree of atness required of the spray.

Anotherobject -isito provide a spray gun having a main air passageway which has a p-air of outlets to'direot air through a pair of opposed jetsand aroundthe nozzle and-to provide an adjustahle means adapted to extend into one of the outlets for-regulating the how of air therethrough and to the opposed jetswhile permitting of a predetermined amount of air to constantly flow through the other outlet and around the nozzle.

A still further object is to provide a needle valve to control the amount of material Which is to be forced throughthe nozzle either'by suction 40 or pressure whereby the air pressure is admitted to the nozzle priorv to the time that the needle valve is opened to any predetermined position.

Anda further object isv to provide a conical member ixedlypositioned over the nozzle of the gun and which member is provided with angularly directed openings which with the shell of the nozzle, serve to form a pair of opposed jets to direct air against the spray tolatten Vthe same, as it `leaves the nozzle.

E Referring to the drawing:

Figure 1 is a medial longitudinal sectional View of a spray gun embodying my improvements.

Figure 2 is a front view of the nozzle end of the spray gun.

.. Figure 3 is an,v enlarged detail cross-sectional view'of the nozzle-taken substantially on'the line 3-3 of Figure l.

Figure 4 is a detail cross-sectional View taken onfthe line 4--4-01" Figure 1.

'Figure 5 is a detail side elevation ofthe nozzle, ,5 illustrating theairpassage therethrough; and

Figure 6 is a detail perspective Vview ofv the conical member positioned over the nozzle.

The-referenoe=numeral I() designates the'body of fthegun Which-is preferably cast of one piece, 10 having a `cored opening II therein; which 'com- Y municateswithan opening I2 in the forward end of the body. VTherearward lend I3 of the cored opening I I is directed downwardly 'and `communicateswith aniopening =I4 that is vparallel to the 15 cored vopening I I, and-which opening is provided with-1a-shoulderl5,-and communicates with a downwardly-directed opening `I6 positioned -rearwardly ofthe1shoulder I5 a-nd intowhich aninlet-pi'pefIfIl-islthreaded; which pipe forms the in- 20 take forthel air'pressure to be app-lied to the gun.

'-Ihevbodyil'ofuthe gun is also provided at its forward endvvitha-downwardly directed extensioni `I 8- which is providedy withabore I 9 4therein that'communicateslwitha horizontallydisposed 25 bore 120 alignedl in -spaced relation with theopening I. This horizontally disposed bore y20 serves to receive the threaded end V2l fofanozzle 22 that isprovidedfwith-a conical bore 2,3 and which has a..:hex formation? 24-which may --be` gripped to 30 threadlthenozzle in positioninto the Yloodyl IIB of the: gun. --On each -side 'of :the'hex formation 24, the 'i nozzle 422 is provided with annular portions 25Jand `26; respectively', through which a plurality 0f.angularly.directediperipheral openings 2l are 35 provided. Ithe nozzle-"22 -is threaded intopositionin v.the-hore'fZIJ, the portion 25 of the nozzle tsrpartiallywithina counter-bore 28 formed in the bore 20 of the body I, and providesan annularlair 'chamber ZBa-.thatcommunicates with 40 the Vangularly directed peripheral openings 2l in the nozzle: 22. This counter-bore 28 communicatesfwith. thev 'corediopening Il` by meansof a drilled opening. 29; lso thatv the lair. Which enters intothe cored opening I I is directed through thedrilled vopening1129 and-into the annular air chamberia. KYThelotl'ier portion 25 of the nozzle 22 is adapted to receivea hollow conical member' 30 which has'one end provided with an annular groove 3l vthat is adapted to t over the 0 portion 25,'fand this member30 serves to direct the air from the rperipheral openings 2'I around thenozzle 22-and-out of an opening 32 in the conical member30. This conical member'SIJ is retained in position-bymeans of a shell-like anconical end 38 of the nozzle 22.

nular housing 33 into which the air is directed from the cored opening I I and through the bore I2. The air that is directed through this bore I2 into the shell-like housing 33 is controlled by means of a set screw 34 which is threaded within a transverse opening 35 that extends across the bore I2, and which set screw is provided with a knurled head 36 for manually adjusting the same to regulate the size of the opening to the bore I2, through which the air passes from the cored opening II into this bore. This set screw 34 is yieldingly retained in its adjusted positions by means of a compression spring 31 that engages the knurled head 35 thereof and the body I0 of the gun.

It will be noted that the main air passage through the cored opening I I is uninterrupted, that is to say, there are no working parts extending through this air passage other than the set screw 34 which regulates the outwardgow of air through the bore I2 into the shell-like housing 33, while the air may freely pass from the cored opening II through the drilled opening 29` into the air chamber 28a and through the angularly directed peripheral openings 21 around the conical end 38 of the nozzle 22, and out of the opening 32 of the conical member 39. This passage of air around the corneal end 38 of the nozzle 22 creates a suction around the nozzle for electing a suction therethrough and through the downwardly directed opening I9 in the body IU to effect a suction and the drawing up of the material to be used for spraying purposes.

The conical member 38 is provided at its free end with an annular flange 39, which has angularly and oppositely disposed milled openings 40 and 4I, respectively, (Fig. 6), that are arranged to converge to a point outwardly of the nozzle 22. When the conical member 30 is retained in position on the body l0 of the gun by the shell-like housing 33, the annular vflange 39 thereof extends flush with an annular opening 42 in the shell 33. 'I'his annular opening 42 and shell 33 serve with the milled openings 40-4I to form jets which direct'the air from within the shell to engage the spray of material outwardly of the nozzle 22.

This type of gun may be used either for the suction type or pressure type of spraying guns and the above description illustrates the manner of operation when a suction type of spraying is employed. The pressure type, as is commonly known in the art, is where an air pressure is applied to the Vmaterial and the ilow of the material is not solely dependent upon the suction created by the passage of air around the nozzle. However, the type of gun illustrated is applicable for use with either the suction or pressure type of material container.

To regulateV the outward flow of the material through the nozzle 22, I provide a'needle valve 43 which has conical end 44 that ts within the This needle valve 43 extends through a packing bushing designated as a whole as 45 and hasa headed portion 46 that is fixed to the end of the needle valve and is retained in and normally spaced with a cup-shaped member 41k which is operatively connected to a swingable member 48 which forms a trigger for manually adjusting the positioning of the needle valve 43 as the gun is operated. The trigger 48 is pivotally carried on a pin 49 that is secured intowa hook-like extension 50 that is an integral part of the body portion I0 of the gun. This extension 50 serves to suspend the gun when not in use. The cup-shaped member 41 also serves to support and engage the free end 5I of a sleeve 52 that is slidably carried in a packing bushing 53 xed into the body I0 of the gun adjacent the cored opening I3. This sleeve 52 is provided with a valve flange 54 at its other end that coacts with a valve seat 53a in the packing bushing 53 and serves to close the air passage between the inlet pipe I1 and the cored openings I3-I I. The sleeve 52 carries a` compression spring 55 therein that engages the inner end thereof and the headed portion 46 of the needle valve 43, and this spring 55 serves to retain the conical end 44 of the needle valve 43 into the conical bore 23 of the nozzle 22 to normally close the same. The sleeve 52 is bodily urged with the ange 54 thereof against the valve seat 53a by means of a compression spring 58 positioned in the opening I4 and which spring has one end engaging the sleeve 52 and its other end engaging a lock nut 51 that is threaded into the opening the needle valve 43 may move to regulate the amount of material to be sprayed through the nozzle 22. A hollow handle 6I is secured to the body I0, and is arranged to extend over the inlet pipe I1, and this handle 6I serves with the trigger 48 as a hand-grip for manipulating the gun.

As thus far described, it will be seen that when the gun is to be operated, the material container (not shown) is attached to the extension I8 and the air pressure is applied to the inlet pipe I1; then the set screw 34 is adjusted to regulate the amount of air desired through the two jets 48 and 4I in the conical member 30, and the set screw 68 is adjusted for the amount of material desired through ythe nozzle 22. As the operator grips the `trigger 48, a sliding movement of the cup-shaped member 41 will be had, which will exert a direct pull upon the sleeve 52 to draw the ange 54 away from the seat 53a of the bushing 53, and upon a further movement of the trigger 48, the cup-shaped member 41 will engage the headed portion 46 of the needle valve 43 and carry the same with the sleeve 52 against the tension of the spring 56, andthe valve flange 54 of the sleeve will be carried from the Valve seat 53a to permit the ypassage of air from the inlet pipe I1 into the cored openings I3-I I, and through the opening 29 and the peripheral openings 21 in the nozzle., This passage of air Y through the angularly directed peripheral openings 21 of the nozzle 22 creates a circulating motion around the nozzle before the air Vexhausts through the annular opening 32 of the conical member 39, and as the material is being drawn through the nozzle, this circulating motion of the air will tend to reduce the material into a relatively cylindrical shape. During this time, the air is also passing through the bore I2 and around the conical member 30, so that a volume of air is contained within the shell 33 and is exhausted through the angularly disposed jets 43 and 4I to again strike the material at a distance outwardly of the opening 32 of the conical member 39. As'these jets 40 and 4I are arranged in Y zle 22 and cause the material to be attened in proportion to the volume of air permitted to be exhausted through the jets by regulating the amount of air through the opening I2 under the control of the set screw 34, the degree of atness of the spray being determined by the volume of air exhausted through the jets.

With the construction of spray gun above disclosed, and a nozzle arrangement coacting therewith, it will be noted that the nozzle is constructed in a smooth, semi-circular manner wherein the two jets 40 and 4I are retained within the nozzle without protruding parts, and wherein the volume of air necessary for eiecting the breaking down or flattening of the material stream after it is compressed upon leaving the nozzle may be varied with respect to the types of objects to be sprayed.

It will be noted that the openings 4D and 4| forming jets in the member are milled diamond-shaped and by this particular shaped opening, the air is directed against the stream of material in a fan-like manner and prevents the clogging and piling up of material on the face of the nozzle.

I claim:

1. A spray gun comprising a body having an air passage and a material passage therein, a anged material nozzle xedly secured to the body and communicating with the material passage, the ange of said material nozzle having openings transversely of the flange communicating with the air passage for directing air around said nozzle, a valve within said nozzle, a hollow open-ended conical member having a conical bore terminating into a reduced opening and fitted to the flange of said nozzle and in spaced relation therewith forming means for directing air therearound, a cup-shaped shell having an opening therein and engaging said conical member and releasably secured to the gun body, said shell forming means for directing air from the air passage around said conical member, said conical member having diametrically opposed angularly directed milled openings serving with the shell to direct opposed streams of air to a common center on the axis of the material flow outwardly of the nozzle.

2. A spray gun as per claim 1, in which the gun body is provided with an annular groove serving with the nozzle flange to accumulate and direct air from the air passage through the opening in the nozzle flange.

GEORGE MCKNIGHT.