US2052362A

US2052362A - Spray gun

Info

Publication number: US2052362A
Application number: US672240A
Authority: US
Inventors: Harold A Roselund
Original assignee: DeVilbiss Co
Current assignee: DeVilbiss Co
Priority date: 1933-05-22
Filing date: 1933-05-22
Publication date: 1936-08-25
Anticipated expiration: 1953-08-25

Description

Aug. 25, 1936. H. A. RosELUND' 2,052,362

' SPRAY GUN Filed May 22, 193s `Patented Aug. 25, 1936 Unirse sr Parary ori-l v attacca spaar cnn poration oi Ohio Application May 22, i933, se'riai No. tra-,24o

3 claims. (ci. 29e-sc).

This invention relates to a spray gun adapted to be attached directly to a small receptacle containing material to be sprayed, and to be carried in the hand while it is used. Compressed air is supplied to the gun by a small air compressor and is controlled by a trigger which first opens the air valve and then the liquid valve. A part of the air stream is directed through the nozzle, while the remainder serves to build up a pressure within the receptacle.

A spray gun of this type is adapted to be supported and manipulated by one hand and, in order that it may not be too heavy, it should be made, as far as practicable, from aluminum. Aluminum, however, is too soft to be advantageously used for both sides of the threaded connection between the top o1 the receptacle and the cap to which the spray nozzle is connected.

One object of the invention, therefore, is to provide a spray gun comprising a liquid container and a cap therefor, both composed chiey of aluminum and having a threaded connection that is reinforced by a collar` of zinc, zinc alloy or similar metal which is materially harder than the aluminum.

Another object of the invention is to provide means for electively preventing any solid particles of the spray material from splashing or being otherwise carried into the air chamber oi the nozzle and clogging it. For this purpose, the air chamber ot the nozzle is separated from the upperl the line 2-2of Fig. 1;

Fig. 3 is a partial section taken on the line 3-3 of Fig. 1; l

Fig. 4 is a detail View of an air cap which may be used interchangeably with that shown in Fig. 1.

Fig. 5 is an enlarged section of the air cap and associated' parts.

The spray gun to which the invention relates comprises a barrel 5 formed at its rear end with a hand grip 6 in front of which is a trigger 1 pivotally connected to the barriel, as shown at 8. The front end 9 of the barrel has an air cap I0 secured thereto by a suitable union Il. Compressed air is supplied by a small air compressor to the barrel 5 through a. port I2 and an air valve I3 controls the ow of the compressed air through a bore til to an air chamber l5 in the front end of the gun from which a portion of the compressed air is emitted through the cap ld along with the liquid coating material which is emitted through an 5 inner liquid nozzle it. The ow of liquid from the bottom ofthe receptacle through a conduit ii is controlled by a needle valve it which is associated with the liquid nozzle iii. The operation of the spray gun, therefore, is eiected through the 10 medium of the trigger i which, as it is pulled back toward the grip t, rst engages the head t@ of the air valve iti to open it against the resistance oi its spring 2u, and then engages the head 2l of the needle valve to open it against the 15 resistance of its spring iii.

The rear end of the gun is pivotally connected at tito the receptacle cap 2t, which is formed centrally with an upwardly disposed hollow extension or neck it terminating in a tapered an-n 20 nular seat it. The barrel t is formed with a correspondingly tapered portion 2i which engages the seat it. The underside of the cap 256i isiormed with an annular seat iii which is adapted to receive a plate 2t. The liquid conduit il, which is 25 secured to the barrel t, has a downward extension iii secured to its lower end by a suitable union di A nut 3i in threaded engagement with the nipple it secures the plate it to its seat it 4and at the same time secures the tapered enlargement 2i 30 oi the gun barrel to the tapered seat it.

A bore dt connects the air chamber it with the cavity it within the cap extension 25 and communicates with the interior of the receptacle it through one or more perforations it formed` inthe plate it. en the gun is in oper-ation, therefore, a part oi' the compressed air passes `trom the chamber iti through the air cap it, while the remainder oi the compressed air flows throughV the bore 33, cavity 34 and ports 36 and serves to build up a pressure within the receptacle 35. In order that the spray material may not pass into the air chamber i5 to clog up4 the nozzle, the cavity 34 is lled with copper wool or equivalent material which constitutes an eilicient lter. n

In spray guns of this type it is'customary for the cap 24 to have e. screw threaded connection with the top *of the receptacle 35. For the sake of lightness, it is desirable to make the gun and the receptacle chiefly of aluminum. This metal, however, is not adapted to be used for both sides of the threaded connection because of the possibility of mutilation of the threads due to the softness of the metal. One side of ythis connec- AAccording to the present construction, this ring 31 is tted over the top of the receptacle 35 and the edge of the receptacle top is then flattened over the upper edge of the ring to form a smooth seat against which rests the gasket 38 within the rim 39 of the cap 24. In order to prevent the ring- 31 from turning with relation to the receptacle top, the ring is formed with notches 40 in its upper inner edge, and the receptacle top is formed with lugs which 'lt therein. p

In order that the ilow of air through the cap I0 may be accurately determined with relation to the pressure upon the liquid within the receptacle 35, the air for atomizing is caused to pass through metering holes 4l, usually four in number, which may be bored with the utmost accuracy through an annular flange 4 Ia provided on the liquid nozzle I6 short of'its tip portion, which latter is also preferably tapered.

The forward end of the gun barrel is cylindrically bored to form the chamber l5, and the cap I0 has its rear or inner end of cylindrical form of a size to t into the outer end portion of the bore forming said chamber. The cap ill is provided in its inner end with the customary cavity for receiving the liquid nozzle I6 and the bottom of such cavity is conical to adapt it to have a tapered seat against the outer tapered edge of the nozzle flange MU'. It is important in the spray heads of guns of this character to have the cap member accurately aligned in coaxial relation to the liquid nozzle, and it is found in practice that such centering is effectively accom'- plished by having the rear end of the nozzle of cylindrical form and tted into a cylindrical recess of the barrel and to cause the bottom of the cap cavity to have a tapered seat against a conical portion of the liquid nozzle, such, for instance, as the ilange 4I". By this arrangement, a tightening of the union Il causes a true centering .of the members I0 and I8 when the parts are in assembled operating relation. The importance of this is emphasized lin a spray gun having a rotatably adjustable cap member which may necessitate frequent loosening of the union I I for cap adjustment purposes.

In certain situations, as for example, in painting a ceiling, with the receptacle 35 nearly full of paint, it is desirable to adjust not only the angle of discharge but also the plane of the fan spray, so that it will not be necessary to tlpthe receptacle enough to permit the paint to ilow through the ports 36. For this reason, it is preferred to construct -the air cap as shown in Fig. 1. In such construction the discharge bore of the cap I0 seats closely on the tapered tip of the liquid nozzle I6 and is provided with passage-v ways I2 through which the metered air from the holes 4| passes. 'I'he cap I0 is also formed with a laterally inclined seat 43, to which a tip 44 is secured by a union nut 45. Thus by loosening the nut Il, the cap I0 may be adjusted circumferentially to cause the iiow to be diverted in any direction desired and by loosening the nut 45 the tip may be adjusted circumferentially to vary the plane of the fan shaped spray emitted from the slit 46 in the tip 44. A standard air cap Ill, as shown in Fig. 4, may, however, be used interchangeably with the cap I0,

By the construction above described I have produced a spray gun'which is inexpensive, yet durable, and which is extremely light and easily manipulated. The cap seats firmly on the receptacle and the gun barrel is seated rmly on the cap so that there is no leakage of the spray material. The packing within the cap prevents the escape of any spray material into the air chamber and this packing may be easily renewed whenever necessary.

Although I have shown and described in detail a specific form of the invention, itis to be understood that this is merely illustrative and may be modified considerably without departing from the scope of the appended claims.

What is claimed isz- 1- A spray gun comprising a liquid receptacle, a cap releasably mounted on said receptacle and having a gasket portion seating on the receptacle end and provided at its central top portion with a hollow upward extension, said extension being open at its top and provided with a conical seat and having a seat at its base portion, a gun body having a conical portion seating on the conical seat of said extension and having a liquid supply tube extending down through said extension and into the receptacle, a plate received by said tube within the receptacle and seating at its edge against the seat at the base of said cap extension, said plate having openings between the receptacle and the hollow of said extension, a nut threaded on said tube and bearing against said plate to effeet opposed clamping coaction off the gun body and plate against their respective seats at opposite ends of the cap extension, said gun body having an air passage in communication with the hollow of said extension.

2. In a spray gun, a barrel body having a chamber in its forward end, a liquid passage and an air passage in communication with the chamlber, a liquid nozzle carried by the body and having a conical tip communicating with said liquldpassage and having a conical portion rearwardly of its tip, which conical portion is formed with air passages extending therethrough. an air cap for said chamber rotatably mounted on the body and having a cavity in its rear into which the liquid nozzle projects and having an air passageway in communication with the air passages of said conical portion of the nozzle and therethrough with the chamber, said cavity having a tapered portion spaced rearwardly of the tip of the nozzle and seated against the conical portion of the nozzle and having a liquid discharge passage receiving the conical tip of the nozzle, and releasable means engaged with the body and with the air cap for drawing the latter` against the conical portion of the nozzle and simultaneously therewith drawing the conical tip of the nozzle against the walls defining the liquid passage of the air cap. I

3. A spray gun in accordance with claim 2 wherein the air cap is provided with an angular tip portion having a common discharge passageway communicating with the respective air and liquid discharge passages of the air cap, said common discharge passageway discharging angularly with respect to the air and liquid discharge passages of the air cap.

HAROLD A. ROSELUND.