US3926376A

US3926376A - Spray gun valve

Info

Publication number: US3926376A
Application number: US578542A
Authority: US
Inventors: Bernard Siczek
Original assignee: Graco Inc
Current assignee: Graco Inc
Priority date: 1975-05-19
Filing date: 1975-05-19
Publication date: 1975-12-16
Anticipated expiration: 1992-12-16

Abstract

Apparatus is disclosed for a paint spray gun valve forming a replaceable cartridge element, wherein the valve may be threadably removed for cleaning and other purposes. A resilient inner sealing member may be used as a valve closure biasing mechanism in addition to providing a seal to prevent the escape of pressurized paint from the spray gun internal paint chamber.

Description

United Sates Patent [191 Siczek Dec. 16, 1975 [52] US. Cl 239/583; 222/518; 251/335 B [51] Int. Cl. B05B 1/30; F16K 31/00 [58] Field of Search..... 251/335 B, 335 A; 239/569,

[56] References Cited UNITED STATES PATENTS 957,347 5/1910 Kennedy ..1 251/335 A X 1,379,357 5/1921 Norman 222/518 X 1,380,973 6/1921 Kelsea .222/518 X 1,681,845 8/1928 Dilley et al. 222/518 X 1,992,067 2/1935 Gunn 222/518 X 2,661,018 12/1953 Snyder 222/518 X 2,969,926 l/1961 Peeps 239/570 X 3,116,020 12/1963 Rosen et al. 239/569 X 3,297,261 1/1967 Heintz 239/584 X 3,836,082 9/1974 Krohn 239/569 X Primary ExaminerRobert S. Ward, Jr Attorney, Agent, or FirmPaul L. Sjoquist [57] ABSTRACT Apparatus is disclosed for a paint spray gun valve forming a replaceable cartridge element, wherein the valve may be threadably removed for cleaning and other purposes. A resilient inner sealing member may be used as a valve closure biasing mechanism in addition to providing a seal to prevent the escape of pressurized paint from the spray gun internal paint chamber.

10 Claims, 3 Drawing Figures US. Patent Dec. 16, 1975 3,926,376

SPRAY GUN VALVE BACKGROUND OF THE INVENTION her to be released through a spray orifice upon activation of a spray gun trigger.

In the field of painting, and particularly paint spraying, there has been developed apparatus and techniques for spraying paints under high hydraulic pressures. The apparatus usually embodies a pistol-shaped spray gun having a trigger which controllably actuates a valve for holding paint in a chamber and emitting it from the chamber through an orifice. Because of the extremely high hydraulic pressures utilized in this type of spray gun the valve must be capable of sealing the internal paint supply from leakage outside the spray gun, even after repeated cycles of opening and closing the valve upon spray gun trigger actuation. As the valving mechanism always has a tendency to wear with repeated use, it should be capable of fast and economical repacement without requiring replacement of the longer wearing components of the spray gun assembly.

In addition, the valve must be capable of external linkage with the spray gun trigger mechanism, and must be adaptable for use with appropriate trigger disabling mechanisms which are made a part of the spray gun for safety reasons.

Improved safety features of the type described above have been incorporated into the present invention spray gun operating mechanism which includes a trigger actuator and a paint spray valve mechanism. As hereinbefore stated, the valve operates to open a passage between the pressurized paint chamber within the spray gun and the paint spray orifice. In such a spray gun apparatus, the pressurized paint line is typically attached to the spray gun, usually to its handle, and internal passages provide a conduit for the pressurized paint to travel to the paint spray orifice openable by the valve.

SUMMARY OF THE INVENTION The present invention comprises a paint spray gun having a paint supply connection directly to the gum body at a point near an internal paint chamber. The apparatus has a novel valve and actuating mechanism for passing paint into the spray tip and sealably confining the internal pressurized paint from leaking external the spray gun. The valve includes a resilient member which closes the paint chamber from external leakage and seals the chamber from leakage along a movable valve rod, wherein the resilient member is shaped to deform in response to internal paint pressures in a manner which increases its sealing capability with increased internal pressure. Further, movement of the valve rod causes the resilient member to deform without relaxing its seal about the rod. When the trigger mechanism is disabled the paint spray valve cannot be opened, thus preventing inadvertent spraying from the paint spray orifice.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the spray gun using the invention; FIG. 2 illustrates the invention in cross-section; and

FIG. 3 illustrates, in partial cross section, another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1, a spray gun which utilizes the invention is shown in side view. A handle 10 forms a portion of the main body of the spray gun, the remaining portion being a barrel 11. A flexible hose 12 designed for connecting to a supply of highly pressurized paint is attached to the underside of barrel 11 by means of a suitable hose connection 16. By way of example, the hydraulic paint pressures intended for use in conjunction with the invention may range from pressures of 500 pounds per square inch (p.s.i.) to 2,000 psi, and it is necessary that hose 12 and body 11 be capable of withstanding pressures exceeding the upper limit of this range. A trigger 14 is used to actuate the spray gun, by opening the paint valve to be hereinafter described. Trigger 14 has a trigger guard 18 in shielding configuration around it in order to prevent inadvertent triggering of the spray gun.

Trigger 14 pivots about pin 20, and its rearward movement is transmitted to trigger lever 22 through its contact point at notch 21. A second trigger lever and notch are also found on the other side of the spray gun, so that rearward forces of movement are distributed evenly across the spray gun assembly. Trigger lever 22 is attached by a bolt 25 or other suitable fastening means to a valve nut 24. Valve nut 24 is connected to the spray gun valve actuating mechanism, to be hereinafter described, so that its rearward movement causes the paint valve to open and allows the spray gun to emit paint spray under high pressure through spray tip 28. Spray tip 28 is clamped against gun body 11 by means of a threaded tip nut 29. This portion of the invention is common and well known in the prior art.

A tip guard 26 forms a protective shield about tip 28 and the region forward of tip 28. Tip guard 26 is also pivotally mounted on pivot pin 20, and the tip guard may be pivoted upwardly to swing clear of the tip 28 end of the spray gun. This pivotal function is necessary in order to enable the operator to loosen tip nut 29 for purposes of cleaning or replacing spray tip 28. The pivot mounting hole in tip guard 26 is positioned to form a lever and cam surface 30 for diabling trigger lever 22 whenever tip guard 26 is lifted out of protective position. It is apparent from FIG. 1 that the lever and cam surface 30 bears against the edge of lever 22 and forces lever 22 downwardly whenever tip guard 26 is raised or pivoted upwardly. This causes lever 22 to disengage from notch 21 and effectively disengages its mechanical contact with trigger 14. With tip guard 26 in an upward position the squeezing of' trigger 14 will not engage lever 22, and therefore the paint spray valve connected to valve nut 24 is prevented from opening to release paint.

FIG. 2 is a cross section of the present invention. A paint passage 32 accepts paint from hose 12 and is in communication with an internal paint chamber 34. Chamber 34 is formed by a bore in barrel 11 and a matching bore in threaded end piece 36. Passing through the center of this bore is a valve rod 35 which protrudes through the rearward end of the barrel and is threadably attached to valve nut 24, and which sealably closes the forward end of the bore by means of ball 40 and seat 46. Valve rod 35 is guided through a seal 38 which is made from a flexible and resilient material such as polyethylene. Seal 38 seals the rear end of bore 34 from leakage to thereby form a pressurized chamber for containing paint. The forward end of valve rod 35 and ball 40 are each held and guided by a retainer 42. A forward shoulder 37 on valve rod 35 bears against a mating shoulder on retainer 42 so that rearward movement of valve rod 35 causes retainer 42 to also move rearward. A compression spring 44 provides a forward seating bias force against the rear edge of retainer 42, and also provides a rearward sealing bias force against the rear portion of seal 38. It should be noted that FIG. 2 illustrates the internal construction of the spray gun valve mechanism with the trigger disengaged. When trigger 14 is squeezed a rearward force is transmitted against valve nut 24. This force acts in opposition to the compression spring 44 force, and also acts in opposition to the force provided by the resilient seal 38. If the trigger is squeezed sufficiently the rearward force overcomes these forces and valve rod 35 moves rearwardly to unseat ball 40. This causes compression spring 44 to compress and causes seal 38 to resiliently deform. When trigger 14 is released compression spring 44 and resilient member 38 provide an immediate and forceful return of ball 40 to its seat 46.

When ball 40 is unseated a passage is opened from chamber 34 to the paint spray orifice 27 according to well known paint spraying techniques and principles. The pressurized paint is forced through orifice 27 to become atomized into small, high-velocity paint particles.

The operation of the spray gun triggering mechanism, including the components which cooperate with valve rod 35, ensures that an adequate paint seal is maintained within chamber 34. For example, the rearward bias of spring 44 against seal annulus 45 holds seal 38 in good paint sealing contact at the real of chamber 34 and around valve rod 35. Further, when valve rod 35 is retracted on trigger engagement, the seal formed around valve rod 35 by retainer 42 and seal 38 is maintained in tight contact. The beveled contact surface between retainer 42 and the forward end of seal 38 causes seal 38 to remain tightly sealed around valve rod 35. Because of its simple construction, the entire assembly consisting of valve rod 35 and ball 40, retainer 42, seal 38 and spring 44 can be easily removed and replaced whenever component wear or other factors dictate such replacement.

In operation, trigger lever 22 provides the mechanical force transfer member between trigger 14 and valve nut 24 for so long as tip guard 26 remains in the lowered position. However, when tip guard 26 is raised, by pivoting it about pivot pin 20, lever and cam surfaces 30 force trigger lever 22 downwardly and out of contacting relationship with notches 21 of trigger 14. This removes the trigger force transfer member from contact with the trigger and prevents valve nut 24 from being actuated by the trigger. When tip guard 26 is returned to its lowered position trigger level 22 can again be latched into contact with notches 21 to make the spray gun trigger operative.

34 from leakage. In this example the biasing force to hold ball 40 on its seat 46 is provided exclusively by resilient member 54, and no supplementary spring biasing force is used. Therefore, when valve nut 24 is moved rearwardly to actuate the spray gun, resilient member 54 becomes deformed by the rearward force on ball 40 by wire 50. Ball 40 lifts from its seat 46 and the pressurized paint in chamber 34 is released through the spray orifice.

Other examples could be provided of modifications and changes within the spirit and scope of the invention, utilizing the novel resilient and deformable sealing member disclosed herein to construct a paint spray valve. The invention provides a means by which a spray gun valve may be economically constructed and quickly replaced whenever it becomes worn through continued usage.

What is claimed is:

1. A safety spray gun apparatus for accepting hydraulically pressurized fluid and for emitting an atomized fluid spray through an orifice under control of an actuating trigger, comprising:

a. an internal valve interposed in the path between said pressurized fluid and said orifice;

b. a valve opening and closing member attached to said valve and projecting externally in actuating contact with said actuating trigger;

c. a resilient and deformable member enclosing said valve opening and closing member in sealing relationship, and urging against said valve to bias said valve in closure position to block fluid flow to said orifice.

2. The apparatus of claim 1, further comprising a retainer member interposed between said valve and said resilient and deformable member, said retainer holding said valve in one end and sealing against said resilient and deformable member at its other end.

3. The apparatus of claim 2, further comprising a spring biasing means for urging against said retainer member in valve closure bias.

4. The apparatus in claim 2, wherein said resilient and deformable member has an annular recess exposed to said pressurized fluid near its end adjacent said valve opening and closing member external projection.

5. The apparatus of claim 4, wherein said resilient and deformable member is constructed of polyethelene plastic.

6. A spray gun valve assembly for controllably actuating the fluid sprayed from an internal fluid chamber through the spray gun orifice by a trigger, comprising:

a. a valve and seat interposed in fluid blockage position upstream of said spray gun orifice;

b. a valve rod connected to said valve and projecting in actuable contact with said trigger;

c. a resilient sealing member surrounding a valve rod portion in said internal fluid chamber and sealing said valve rod projection from said chamber, said resilient member urging said valve to valve closure position;

(I. a compression spring producing a spring force between said resilient sealing member end internal said chamber sealing said valve rod projection, and said valve.

7. The apparatus of claim 6, further comprising a valve holder member interposed in contacting relationship between said valve and said resilient sealing member.

near the valve rod projection, said groove sized to seat one end of said compression spring.

10. The apparatus of claim 9 wherein said valve holder member further comprises a shoulder for seating said other end of said compression spring.

Claims

1. A safety spray gun apparatus for accepting hydraulically pressurized fluid and for emitting an atomized fluid spray through an orifice under control of an actuating trigger, comprising: a. an internal valve interposed in the path between said pressurized fluid and said orifice; b. a valve opening and closing member attached to said valve and projecting externally in actuating contact with said actuating trigger; c. a resilient and deformable member enclosing said valve opening and closing member in sealing relationship, and urging against said valve to bias said valve in closure position to block fluid flow to said orifice.

6. A spray gun valve assembly for controllably actuating the fluid sprayed from an internal fluid chamber through the spray gun orifice by a trigger, comprising: a. a valve and seat interposed in fluid blockage position upstream of said spray gun orifice; b. a valve rod connected to said valve and projecting in actuable contact with said trigger; c. a resilient sealing member surrounding a valve rod portion in said internal fluid chamber and sealing said valve rod projection from said chamber, said resilient member urging said valve to valve closure position; d. a compression spring producing a spring force between said resilient sealing member end internal said chamber sealing said valve rod projection, and said valve.

8. The apparatus of claim 7, wherein said valve rod further comprises a shoulder contacting said holder member for transmitting valve opening force to said holder member.

9. The apparatus of claim 8, wherein said resilient sealing member further comprises an annular groove near the valve rod projection, said groove sized to seat one end of said compression spring.