US3380705A - Spray gun - Google Patents

Description

April 30, 1968 B. E. ENSSLE 3,380,705

SPRAY GUN Filed June 28, 1965 United States Patent O 3,380,705 SPRAY GUN Bruno E. Enssle, Boulder, Colo., assignor to Binks Manufacturing Company, Chicago, Ill., a corporation of Delaware Filed June 28, 1965, Ser. No. 467,635 12 Claims. (Cl. 251-89) ABSTRACT F THE DISCLOSURE An airless paint spray gun characterized by safety features mitigating misuse of the gun and injury to human beings; specifically, a control knob for disconnecting the gun trigger from the uid control valve for preventing inadvertent opening of the valve during cleaning, replacement of nozzles and Ithe like, and a valve and valve seat arrangement such that a solid jet of fluid cannot issue from the gun when the nozzle is not in place. A further characterizing feature resides in a readily replaceable valve and sealing gland cartridge for airless spray guns facilitating cleaning and repair of the gun; said cartridge including a flexible link in the valve actuating means facilitating broad manufacturing tolerances.

The present invention relates to apparatus for spray painting, and particularly, to an improved airless spray painting gun. The object of the invention is to provide improvements in spray painting guns facilitating manufacture, assembly and repair of such guns.

It is in particular an object of this invention to provide an airless spray gun incorporating the safety feature that the gun cannot be operated during replacement, cleaning or inspection of the gun nozzle, whereby to avoid injury to the operator or bystanders consequent upon inadvertant or accidental operation of the gun. Specifically, in airless spray painting, paint or other coating material is supplied to the gun at pressures of up to 3,000 pounds per square inch, and this paint or coating material is hydraulically atomized by passage through a Very small orifice in the gun nozzle. The coating material issuing from the nozzle is at such high pressure and traveling at such high speed that it is capable of severing a finger or inflicting great bodily harm by penetration of the coating material through the skin of the person who is inadvertantly or accidentally sprayed. Should the spray hit a vital portion of the human body, it is quite likely that death might result. Accordingly, the incorporation of the safety feature of the present invention in an airless spray gun affords very substantial practical advantages.

Another object of the present invention is to provide a combined valve and sealing gland cartridge for spray guns characterized in that the cartridge is insertable in and removable from the gun body as a unit, whereby to facilitate manufacture and assembly, cleaning repair of the gun.

A further object is the provision of a valve and seal cartridge as aforesaid embodying fiexible valve stem means accommodating broad dimensional tolerances in manufacture of the gun; and also embodying a spring confined between the valve and `the sealing gland for both biasing the valve to its seat and maintaining the gland in sealing relation to the gun body and the valve stem.

A still further object of the invention is the provision of an improved valve and valve seat for spray guns facilitating economical manufacture of the same from wear resistant materials, providing a quick-opening valve port, mitigating pulsations in material delivery and splitting of the spray gun, and also affording certain safety factors in use of the gun.

3,380,705 Patented Apr. 30, 1958 ICC These and other objects and advantages of the invenf tion will become apparent in the following detailed description.

Now, in order to acquaint those skilled in the art with the manner of making and using the spray gun of the present invention, there shall be described in connection with the accompanying drawings, a preferred embodiment of the spray gun and the preferred manners of making and using the same.

In the drawings:

FIGURE 1 is a top view, partly in plan and partly in horizontal section, of a preferred embodiment of the spray gun of this invention;

FIGURE 2 is a vertical longitudinal section of the gun taken substantially on line 2 2 of FIGURE 1;

FIGURE 3 is a rear elevation of the gun, the view being taken from the right of FIGURE 2 and showing the gun in safety position;

FIGURE 4 is a fragmentary longitudinal section of the gun taken substantially on line 4-4 of FIGURE l; and

FIGURE 5 is a fragmentary enlargement of a part of FIGURE 2 showing the valve and valve seat members.

Referring to the drawings, the airless spray gun of the present invention is shown as comprising a gun body 10 including a handle 12 and a head portion 14. The head portion 14 is provided with a longitudinal bore 16 extending therethrough, and the handle is provided with a diagonal bore 18 communicating with an intermediate portion of the bore 16. A nipple 20 is threaded into the bore 18 at the lower end of the handle for supply thereto of coating materials.

The forward end of the longitudinal bore 16 receives a threaded fitting 22 which in turn threadably receives a valve seat retainer 24, the latter removably mounting a valve seat 26 and a combined seat locking stud and valve guide 28 in the front of the gun body. The fitting 22 also threadably receives a cap 30 which detachably mounts an airless spray nozzle 32 on the lgun body in alinement with the port in the valve seat 26, a seal 34 suitably being inserted between the nipple and the retainer 24.

Slidably inserted in the longitudinal bore 16 is a selfcontained valve cartridge 36 comprising a valve member formed of a ball valve 38 and an integral needle portion 40, an integral rigid threaded stem portion 42, a fiexible stem link 44- adjustably connected to the portion 42, a packing gland assembly 46 slidably receiving the stem link 44, a stem extension 48 having a one-way connection with the rearward end of the link, a retainer 50 for the gland assembly 46 and the extension 48, and a compression spring 52 encircling the stem between the portion 42 and the gland assembly 46.

The link 44 is comprised of a length of flexible wire provi-ded with a head at each end thereof. The head at the forward end of the wire is slidably received in a collar 54 which is threaded on the stem portion 42 to facilitate adjustment between the two, the collar when adjusted being secured to the portion 42 by a lock nut 56. The head at the rearward end of the flexible wire is slidably received in the extension 48, and the extension has only a rearwardly facing seat for the head whereby the extension can operate only to pull the wire rearwardly. The iiexible wire particularly accommodates mis-alinement of the valve 38440 and the packing gland, extension and retainer 46-48-50 without introducing lost motion in the interconnection of the valve and the extension, whereby to alleviate the degree of precision required in machining the body 10, i.e., the retainer 50 and the valve seat 26 may be mis-alined without disadvantageous consequences.

The flexibility afforded by the link 44 also contributes to attainment 'of exceptionally effective results of an improved needle valve and valve seat structure provided in accordance with this invention, which structure per se affords substantial advantages in the art. Specifically, the invention provides a ball type needle valve and valve seat wherein both the ball and the seat may be fabricated of extremely wear resistant materials, notably tungsten carbide, and yet afford an effective seal therebetween; whereas it has heretofore been necessary in ball type needles -to form one of the members of tungsten carbide and the other of a softer material, or in the alternative to adopt a conventional needle valve rather than a ball valve.

As shown in FIGURE 2, the ball 38 is a sphere welded or otherwise secured to the stern 40, and the valve seat 26 is a unitary member having a conical recess in the rear face 4thereof forming the valve seat. Consequently, with the supplemental aid of the freedom of movement afforded by the link 44, the ball 38 is funneled or cammed by the conical seat 26 into a perfectly seated engagement with the seat along a continuous circular line of seating contact. In the preferred embodiment, the conical bore forming the ball seat is extended continuously through the seat member 26 to form a valve port only slightly smaller than the diameter of `the ball, whereby the ball 38 sits within the port substantially flush with or projecting forwardly of the front face of the member 26. This disposes the valve as close as possible to the spray nozzle 32V and results in mitigation of spitting and spray pattern deficiencies at the time when the valve is opened and closed and the supply of material to the nozzle is initiated and discontinued. Also in the preferred embodiment, the conical valve seat has a fairly wide flare (eg` 60 or more degrees) so that the ball is operative to fully open and to close the port quickly to mitigate spitting and spray pattern deficiencies. Moreover, the ball in its open position deflects the material passing through the port in such manner as to form a spray (not a solid jet of material) when the nozzle 32 is removed, whereby to afford a further safety factor for the operator when inspecting or replacing the nozzle.

To mount the valve stem retainer 50, the bore 16 is formed with a radially inwardly directed shoulder at a location rearwardly of the point of intersection therewith of the diagonal bore 18, and the retainer is provided with a flange engaging said shoulder. The retainer in turn defines a first forwardly facing seat for the gland assembly 46. The gland assembly comprises a rearwardly disposed gland backing 58 engaging the seat therefor in the retainer, a generally conical piece of compressible packing gland material 60, a gland seat 62 having a rearwardly facing conical recess receiving the piece 60 of gland material, and a spring mount 64 forwardly of the gland seat. In use, `the spring 52 urges the valve 38-46 forwardly against its seat 26 and urges the gland assembly rearwardly to seat the backing 58 in the retainer 50 and to exert a compressive force on the conical surfaces of the gland material to cause the gland to be squeezed radially outwardly and inwardly into sealed engagement with the retainer 50 and the flexible link 44.

Rearwardly of the gland seat, the retainer 50 is formed to define a safety stop or shoulder for the stem extension 48, the extension having a radial flange at its forward edge normally spaced forwardly of the stop or shoulder. In use, the stop and flange positively prevent excessive rearward movement of the extension 48 and thus prevent excessive pulling stress on the valve stem. In addition, the particular advantage is afforded that should the iiexible link break or become disassociated from the head at the forward end thereof, the extension 48 cannot be pulled (or pushed by fiuid pressure) so far rearwardly as to disassociate the link from the sealing gland 60, thereby to prevent leakage from the gun even if the valve stem is broken.

In the preferred embodiment of the gun, a cylindrical paint `strainer 66 is extended between the retainers 24 4 and 50 to cause the paint to be strained in its passage from the supply duct 18 to the spray nozzle 32.

The retainer 50 and the valve stem extension 48 extend rearwardly of the exterior of the gun body and define mounting surfaces rearwardly of the body for a manually manipulatable safety knob 68. The knob lhas a forward cylindrical bore conformably receiving and rotatably mounting the knob on the retainer 50, an intermediate bore 69 of non-circular cross-section engaging a non-circular portion of the extension 48 and connecting the two together for conjoint rotation, and a rearwardly open cylindrical bore receiving a nut or threaded abutment 70 that is adjustably threaded on the stem extension 48. The abutment 70 is spaced slightly rearwardly of the opposed surfaces of the knob, but is adapted for engagement by the knob upon rearward movement of the latter to exert a rearward pull on the valve stern to open the valve. A set screw 72 locks the abutment 70 in adjusted position on the extension 48, and a spring 74 forming part of a detent means is Confined between the knob and the abutment to urge the knob forwardly toward the gun body and to urge the abutment rearwardly to eliminate lost motion between the extension 48 and the exible stem link 44.

A valve actuating trigger is pivotally mounted on the head portion 14 of the gun body, the trigger including a nger grip portion 76 forwardly of the handle 12 and a pair of bifurcations 78 extending to opposite sides of the head 14 and pivotally connected thereto by screws 80 or the like. Preferably, the head portion 14 is recessed at its opposite sides to receive the bifurcations 78, whereby portions of the body rearwardly of the trigger are alined with the two bifurcations. Slidably mounted in the latter portions of the gun body are a pair of actuator rods 82 which extend forwardly into the recesses provided for the bifurcations and rearwardly to the rear face of the gun body, the rods or pins being trapped in operative position by C-rings 84 engaging the portions thereof between the gun body and the trigger bifurcations. To eliminate or control Wear between the rods and the trigger, and to accommodate economical formation of the trigger, a wear plate 85 is provided between each bifurcations 78 and the head of the adjacent rod 82. Each wear plate 85 preferably comprises a tab portion complementing the upper end of the trigger bifurcation and pivotally mounted on the respective screw 80, and an outturned tab extending into a recess in the rearward face of the bifurcation at a point alined with the respective rod 82.

In the illustrated embodiment of the invention, as shown particularly in FIGURES 1 and 3, the rods 82 are disposed parallel to the valve stem at the same elevation and equal distances to opposite sides of the stem. The knob 68 is of generally elliptical configuration in rear elevation and includes a pair of oppositely extending eccentric portions 86 selectively rotatable into and out of alinement with the rods 82. When the eccentric portions are alined with the rods, squeezing of the trigger causes the rods to move the knob rearwardly, the knob in turn engaging the abutment 70 and thereby pulling rearwardly on the stem components 48, 44 and 42 to open the valve 38-40. When the trigger is released, the spring 52 causes all of the components to return to their normal positions as illustrated in FIGURE 1 wherein the valve is closed.

Should it be desired to render the gun inoperative, for example when the gun is idle, and to afford in particular the safety feature that the gun cannot be operated during replacement, cleaning or inspection of the nozzle, it is only necessary to rotate the knob 68 a fraction of a turn to move the eccentric portions 86 out of alinement with the rod 82. In this condition, the trigger and the rod cannot lmove the knob 68, and the knob itself cannot be moved except by extreme purposeful efforts, whereby the valve cannot be opened accidentally or inadvertantly. Consequcntly, accidental or unpremeditated actuation of the trigger will not result in opening the valve, and danger of injury to the operator or bystanders from the high pressure coating material emanating from the nozzle 32 is alleviated.

The knob 68 and actuator rods 82 are preferably provided with detent means for rereasably retaining the knob extension 86 in alinement with the rods 82 and for deterring re-alinement of the same when in safety position, thereby to enhance the safety feature and render the same more positive. To this end, detent balls 88 are secured in sockets that therefor in the knob extensions 86 and the rearward ends of the rods 82 are provided with conical recesses 90 for reception of the balls, the spring 74 normally retaining the knob and thus the balls 88 in engagement with the rearward surface of the gun body and the rearward ends of the rods. Also, the trigger is inclined forwardly from its pivots 80 whereby the pendulus weight of the trigger portion 76 exerts a rearward biasing force on the rods to maintain the rods in engagement with the detent balls. When the knob is rotated to safety position, this same pendulum action of the trigger shifts rods 82 rearwardly of the gun body, whereby the rods prevent rotation of the knob back to operative position. Only when the trigger is released and the gun is pointed downwardly (which is a safe holding position for the gun) will the trigger and the rods move forwardly to permit the knob to be rotated back to operative position. Thus, operator safety is assured.

The gun construction above described, in addition to the advantages already noted, facilitates rapid assembly and disassembly of the gun for convenience in manufacture and for convenience in the field when it is desired to clean the gun or repair or replace parts thereof. Specifically, the knob 68 may be held against rotation, thereby to hold the stem extension 4S against rotation so that the set screw 72 may be loosened and the abutment 70 removed from the stern extension. Then, by holding the body of the gun, the nozzle cap 39 may be unscrewed, and the retainer 24 may be removed from the forward end portion of the gun. Thereafter, the self-contained valve cartridge 36 and strainer 66 may readily be removed as a unit from the oun body simply by pulling on the valve 38-40.

Thus, the objects and advantages of the invention have been shown herein to be attained in a convenient, economical and practical manner.

While a preferred embodiment of the spray gun of the invention has been illustrated and described herein, it is to be appreciated that various changes, rearrangements and modifications may be made in such embodiment" without departing from the scope of the present invention, as defined by the appended claims.

What is claimed is:

1. In a spray gun or the like, a body, a valve seat in the body, a valve movable to and from the seat to control fiuid flow, said valve having a stem extending to the exterior of the body, la knob engaging said stem exteriorly of said body, and an actuator rod slidably mounted into the body in spaced generally parallel relation to said stem, said knob including -a portion movable into and out of alinement with said -rod to accommodate and prevent, respectively, actuation of said valve.

2.. In a spray gun or the like, a body, a valve seat in the body, a valve movable to and from the seat to control fluid ow, said -valve having a stem extending to the exterior of the body, a knob engaging said stem exteriorly of said body, and an actuator rod slidably mounted in t-he body in spaced generally parallel relation to said stem, said knob including la portion movable into and out of alinement 4with said .rod to accommodate and prevent, respectively, actuation of said valve, said rod and said knob including detent means normally retaining said portion of said knob in alinement with said rod and deterring realinement of said portion with said rod when the two rare not in alinement.

3. In a spray gun or the like, a body, a valve seat in the body, a valve movable to and from the seat to control fluid flow, said valve having a stem extending to the exterior of the body, a knob engaging said stem exteriorly of said body, a trigger ypivoted on said body including bifurcations to opposite sides of said stem, and a pair of rods slidably mounted in said body to opposite sides of and generally parallel to said stem, said rods extending Ibetween a respective bifurcation of said trigger and said knob7 said kno-b including op positely extending eccentric portions rotatable into and out of alinement with said rods to accommodate and prevent, respectively, actuation of said valve by said trigger.

4. In a spray gun or the like, a body, a valve seat in the body, a valve movable to and from the seat to control fluid flow, said valve having a stem including a rigid portion adjacent the valve, a stem extension remote from said valve and extending to the exterior of the -body 'and a exible intermediate portion, a spring between the body and said rigid portion normally biasing said valve towar-d said seat, a knob engaging said stem extension exteriorly of said body, and an actuator rod slidably mounted in lthe -body in spaced generally parallel relation to said stem and movable conjointly therewith to open and to accommodate closing of the valve, said knob including a portion movable into and out of alinement with said trod to accommodate and prevent, respectively, opening of said valve.

5. In a spray gun or the like; a body having a forwardly open fluid passage including a rearwardly spaced forwardly facing seat; a valve assembly slidably positioned in said passage, said assembly comprising a -forwardly disposed valve, a valve stem including :a flexible link extending rearwardly from said valve, sealing gland means slidably receiving said .link and engaging against said forwardly facing seat, and means between said valve and said gland means for exerting a compressive force on said gland to cause the salme to seal in said passage and about said link and for biasing said valve forwardly; and -a valve seat removably inserted in the forward end of said passage for co-operation with said valve.

6. In a spray gun or the like; a body having a forwardly open fluid passage including a rearwardly spaced forwardly facing seat; a valve, valve spring and packing gland assembly slidably positioned in said passage, said assembly comprising a forwardly disposed valve, a valve stern including a exible link a-djustably connected to said valve and extending rearwardly from said valve, a gland seat slidably receiving said link and having a rearwardly facing conical seat, -a conical gland slidably `receiving said link and engaging in said gland seat, -a gland backing slidably receiving said link and engaging against said forwardly facing seat, and a compression spring encircling said link and extending between said valve and said gland seat for exerting a compressive force on said gland to cause the same to seal in said passage and about said link and for biasing said valve forwardly; la valve seat Iremovably inserted in the forward end of said ypassage for co-operation with said valve; and means .rearwardly of said gland detachably connected to said link for pulling said valve away from said valve seat.

7. In a spray gun or t-he like, a valve cartridge comprising `a valve, a valve stem including a rigid portion extending rearwardly from said valve, -a flexible link, means -adjustably connecting said link to said rigid portion, and an extension on the rearward end of said link, packing gland means slid-ably receiving said Ilink between said connecting -means and said extension, a retainer for said extension and said gland means including a forwardly facing seat for said gland means, and means between said valve and said gland means yieldablly urging said valve forwardly and said gland means rearwardly toward its seat.

8. A spray gun comprising a igun body having a fluid passage therein including a bore extending longitudinal-ly through the body from the front to the rear thereof, a valve seat removably mounted in the forward end of said bore, a valve slidably positioned in said bore and engageable with said seat, a rearwardly extending stem on said valve, packing gland means seated in said bore and slidably .receiving said stern, means between said valve and said gland yield-ably iurging said valve forwardly to its seat and said gland means rearwardly to its seat in said bore, an abutment member rearwardly of said body adj'ustably connected to said stem, a knob engaging said abutment member rearwardly of said body, an actuator rod slidably mounted in said body in spaced generally parallel rela-tion to said stem and exten-ding to the rear of said body, said knob including a portion movable into and out of alinement with said rod to accommodate and prevent, respectively, movement of said knob vby said rod, and means for moving said rod.

9. A spray gun comprising a gun body having a duid passage therein including a 'bore extending longitudinally through the body from the front to the rear thereof; a valve seat removably mounted in the forward end of said bore; a valve cartridge slidably positioned in said bore including a valve engageable with said seat, a rearwardly extending valve stem including a iiexible link adjustably connected to the said valve, a packing gland assembly slidably receiving said stem, a retainer seated in said bore adjacent the rear thereof and providing a forwardly facing seat for said gland, a spring encircling said stem between said valve and said gland assembly and urging said valve forwardly to its seat and said gland assembly rearwardly to its seat, and a stem extension connected to said stem rearwardly of said gland assembly for transmitting only rearward pulling force to said stem; an abutment member adjustably connected to said extension rearwardly of said body; a rotatable knob engaging said abutment member rearwardly of said body; a pair of actuator rods slidably mounted in said body to opposite sides of and generally parallel to said stem and extending to the rear of said body; said knob including oppositely extending eccentric portions rotatable into and out of alinement with said rods to accommodate and prevent, respectively, rearward movement of said knob by said rods; detent means between said knob and said rods normally retaining the eccentric portions of said knob in alinement with said rods and deterring re-alinement of the same when they are not in alinement; and means for moving said rods.

10. In a spray gun having a body and a nozzle detachably secured to the front end of the body, a valve seat member mounted in the body at the front end thereof, said member having a conical bore extending substantially entirely therethrough and defining a valve port of practically no axial extent at substantially the plane of the front end of said member and a conical seating surface rearwardly of said port, and a generally spherical valve member yieldably biased against said seating surface and retractable from said surface and out of said port for causing liquid to follow the contour of said seating surface and emanate from said port as a spray when the nozzle is detached from the body.

11. In a spray gun as set forth in claim 10, said valve member comprising a valve ball of a diameter only slightly greater than said port and projecting into at least substantially the plane of said port.

12. In a spray gun as set forth in claim 11, stem means on said valve ball including a exible portion accommodating movement of said ball relative to said seating surface.

References Cited UNITED STATES PATENTS 1,249,090 12/1917 Hoff 251-333 X 1,675,979 7/1928 Laird.

1,941,134 12/1933 Dodge 251-89 2,579,567 12/1951 Greene 251-155 X 2,694,410 11/1954 Ey 251-356 X 2,942,791 6/1960 Bush et al. 239-526 X 3,000,576 9/1961 Levey et al. 239-526 X 3,077,896 2/1963 Weingard 251-333 X 3,116,020 12/1963 Rosen `et al. 251-294 X 3,190,564 6/1965 Liedberg 251-294 X M. CARY NELSON, Primary Examiner.

R. C. MILLER, Assistant Examiner.

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