US2677525A - Spray gun - Google Patents

Description

May 4, 1954 L. E. PAVEY EI'AL SPRAY GUN Filed Feb. 17, 1948 INVENTORS LARRY E. PAVEY BY ALBERT ALLEN C05 70 ATTORNEYS Patented May 4, 1954 SPRAY GUN Larry E. Pavey and Albert Allen Coe, Seattle, Wash.

Application February 1'7, 1948, Serial No. 8,807

1 Claim. 1

The present invention relates to a spray gun for use with a source of liquid under pressure, to spray that liquid upon surfaces to be coated. Such spray guns are used, for instance, in the spraying of insecticides or the like upon plants, or for spraying paint upon surfaces to be painted.

A primary object of this invention is to provide a spray gun which is of simple, light construction, and which can be manufactured with a minimum number of parts, which as a whole require a minimum of precision operations, and made in part, at least, of parts which are largely standard in form and readily available in quantities.

At the same time, of course, it is an object to provide a spray gun which is tight against elevated pressures, even pressures of the order of one hundred pounds per square inch, and which will promptly cut off delivery without drip and resume delivery without delay.

It is also an object to provide a spray gun which is readily assembled and disassembled for cleaning, even to the packing, and which in particular avoids long, intricate passages wherein materials may collect and from whence they are difficult to dislodge.

Still another object is to provide a protective element for the trigger, and to balance the gun for convenience of use, by a special arrangement of the supply conduit relative to the barrel and handle portions, respectively, of the frame.

With such objects in mind, and others as will appear hereinafter, the present invention comprises the novel spray gun, and the novel combination and relationship of the parts thereof to one another, as shown in the accompanying drawings, described in this specification, and defined by the claim.

In the accompanying drawings the invention is shown embodied in a form which presently is preferred by us.

Figure 1 is a general axial sectional elevation through the spray gun, showing parts fully assembled, and with the parts in position to cut ofi discharge, and Figure 2 is a similar view showing the spray gun partly disassembled.

Figure 3 is a transverse sectional view, enlarged, on the line 3-4 of Figure 1.

Figure/l is an enlarged detail View, and Figure 5 is a similar detail view in transverse section through a part of the spray gun.

The spray gun in the form shown includes a frame shaped similarly to a pistol, and including a barrel portion l and a handle portion l0.

This frame may conveniently be formed as a die casting, of light metal. In the forward portion the barrel l is recessed to define a chamber H, closed by a removable nozzle tip 2 and threaded cap 20, the whole being sealed by a centrally apertured sealing washer 2i. The fine bore 22 through the nozzle tip 2 constitutes the outlet from the chamber II, and the lateral passage l2 constitutes the inlet to the chamber, and is connected, preferably by a flexible hose 3, and not through passages in the frame, to a source of liquid under pressure, the precise nature of which is immaterial to the structure of the spray gun. For convenience of handling, for better balance, and as a guard for the trigger, the hose 3 is supported from the rear portion of the handle it in ahanger 3|.

The chamber H has a third aperture in its rear portion at 13, in longitudinal alignment with the outlet aperture 22, and this aperture it constitutes a sliding guide for a rod 4, which fits snugly within the aperture l3, and which projects forwardly within the chamber H to an extent suiiicient to close the outlet 22, in a mannerwhich will be explained more fully hereinafter. The rod 4 also extends rearwardly from the aperture 13, through an intermediate U- shaped section of the barrel portion, and its rear end is received within a bore id in the rear of the barrel portion 1 of the frame, which bore is aligned with the aperture i3 and the outlet 22.

The construction of the rod 4 and its cooperation with other parts of the gun are important parts of the present invention. This rod is preferably of uniform diameter throughout, with certain exceptions to be pointed out shortly, and therefore can be made of standard rod stock. Its ends, at least its forward end, are preferably cut squarely on, and therefore it needs no forming in this respect, but can be sawed off to correct length, and then finished, if at all, merely by grinding its end face. This forward end of the rod is intended to seat upon the sealing washer 2i, whereby to seal oh the outlet 22. The portion which is slidably received within the rear aperture 13, when the ti is thus seated, is circumferentially grooved (see Figure 4) as is indicated at 5!, and Within this groove is received a resilient O-ring or like sealing member 42, which should be of a size to seat at all points within the walls of the aperture [3, and which also preferably seats upon the bottom of the groove 4!, being compressed, when in use, between the walls of the aperture and the bottom of the groove. The extent of operative sliding movement of the rod is never sufficient to project the sealing ring 42 beyond the confines of the aperture l3, but for assembly the rear entrance to the aperture 13 should be somewhat cupped, as is seen in Figure 1, to guide and compress the ring 42 as it enters the aperture [3.

The operative movement of the rod 4 is restricted, and the rear end of the rod is guided, by a removable cap l5, threadedly received within and closing the rear end of the bore [4, the rod being of such length as to permit its limited lengthwise movement, but to contact the cap 5 for limitation of its rearward movement.

A trigger 5 is supported in the frame for forward and rearward movement. Conveniently it is pivotally mounted at 5| within the frame, and hangs downwardly, straddling the rod 4. To this end the trigger is notched, as indicated at 52 in Figure 3. In order that the trigger may engage the rod 4 and pull the same rearwardly, and in order that a compression spring 6 may urge the rod forwardly, shoulders must be provided on the rod '5, but since the rod is of material of uniform diameter, and forming operations thereon are not desirable, such shoulders are formed. by encircling the rod with an abutment member such as the sleeve 44, which is held to the rod by crimping it at diametrically opposite points, indicated at 43 (see Figure 5), within a circumferential groove 45 cut or ground within the rod. The forwardly facing shoulder, formed by the forward end of the sleeve 44, will be engaged by the edges of the notch 52 of the trigger 5, whereby to draw the rod rearwardly, and the spring 0, which is coiled about the rear end of the rod, seats between the rearwardly facing shoulder, which is the rear end of the sleeve 44, and the cap 15, in the manner shown in Figure 1. The sprin therefore urges the rod resiliently forwardly to seat its forward end as a valve against the seat formed by the washer 2|. Integrally formed stop shoulders ll, projecting inwardly from the walls of the barrel portions U-shaped section, engage and limit undue forward swinging of the trigger 5, or forward thrust of the rod 4 whenever the tip 2 is removed.

The sleeve 44 and the spring 6 constitute the greatest radial extent of the rod, or of any parts associated with the rod. The bore [4 is large enough to pass the spring and the sleeve, consequently when the cap is removed the rod 4, completely assembled, may be slipped through the bore M, in the manner shown in Figure 2. In assembling parts the forward end of the rod 4 may be pushed through the aperture 13, the sealing ring 42 will be crowded inwardly into sealing engagement with the inside wall of the aperture l3, and when the rod is thus in place, the cap 15 may be threaded into the end of the bore Hi, and secures parts in this assembled position, and in so doing compresses the spring 8. No other engagement or disengagement of parts is necessary. There is no need to orient the rod about its axis, nor longitudinally with respect to the trigger or any other part. The structure is therefore extremely simple to take apart and clean, to reassemble, to change the size of the outlet aperture, and yet all parts seat tightly and securely. The O-ring will hold pressures of the order of one hundred pounds per square inch without difficulty, and because the cut-off is close to the outlet tip, cut-off is instantaneous, and there is no drip. Parts are CII simple to construct and to assemble, and the rod, being of standard stock, with but little or no machine work, can be made readily and cheaply in large quantities.

Whenever the gun needs cleaning, which of course is at least as often as it is used, the simple, open construction makes the job simple, hence most likely to be done thoroughly. The simplicity of assembly and disassembly has already been shown; by disconnecting the supply hose 3 from the inlet at I2, and by removing the spray tip 2, all parts of the small chamber H are readily accessible. All passages are straight, and accessible, with an absolute minimum of hidden or intricate passages 0r ports.

We claim as our invention:

A spray gun comprising a one-piece frame including a handle portion and a barrel portion, said frame being further formed with a chamber at its forward end and a bore at its rear end, means providing an outlet from and a valve seat interior-1y of and at the forward end of said chamber, said barrel portion having a circular guide aperture opening into the rear end of said chamber in alignment with the valve seat and said bore, a one-piece, round-section valve rod which throughout its entire length, except as it is grooved, of uniform diameter, to fit snugly within said guide aperture, whereby it may be formed of standard rod stock, said valve rod being formed at its forward end as a valve tip for cooperation with said valve seat, and being of a length to extend rearwardly into said bore, said valve r d being circumferentially grooved intermediate said guide aperture and said bore, an abutment member outstanding from said rod and having a portion constricted and thus anchored within said groove against longitudinal movement, said rod being of a size for ready withdrawal rearwardly therethrough of the valve rod and the abutment, a removable closure for bore formed to receive and guide the rear end portion of said rod for reciprocation, a com pression spring between the rear end of said abutment and said closure, reaching from the latter to urge said valve rod forwardly to seat its valve tip and thus close the valve, a trigger supported in said barrel portion in position for engagement with and movement of said abutment member to urge said valve rod rearwardly in opposition to said spring to open said valve, and a pressure conduit for material to be sprayed connected to said chamber.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,788,810 Tittemore Jan. 13, 1931 1,806,447 Carson May 19, 1931 1,844,460 Butler Feb. 9, 1932 1,884,991 Gerdts Oct. 25, 1932 1,908,848 Jenkins May 16, 1933 1,910,909 Werder May 23, 1938 1,970,546 Clapper Aug. 21, 1934 2,082,061 Jenkins June 1, 1937 2,105,903 Clizbe Jan. 18, 1938 2,107,686 Bramsen Feb. 8, 1938 2,195,811 Bramsen Apr. 2, 1940 2,431,437 Van Der Werff Nov. 25, 1947 2,497,625 Norwick Feb. 14, 1950 2,552,907 Peeps May 15, 1951

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