US 3743188 A
A spray gun of the type used for spraying paint and the like which has a gun body with a depending handle, the handle being hollow and having a filter unit disposed axially therein, the filter unit being spring-biased so as to eject for easy removal.
Description (OCR text may contain errors)
Unite States Patent 1191 Wagner July 3, 1973 1 SPRAY GUN  References Cited  Inventor: Josef Wagner, Markdorferstr. 165, UNITED STATES PATENTS 7991 Friedrichshafen-Fischbach, 1,835,865 12/1931 Hansen 239/DlG. 14 Germany 3,065,918 11/1962 Hostetter 239/575 2,265,209 12/1941 Thompson... 239/D1G. l [221 Flledl 91 1971 3,285,420 11/1966 Muller 210/352  Appl. No.: 197,095
Primary Examiner-Lloyd L. King F n A u r P i D m Att0rneyCarlt0n Hill, James Van Santen et al.
orelg pp ca ion r on y a Nov. 13, 1970 Germany P 20 55 936.8 57 ABSTRACT 1 A spray gun of the type used for spraying paint and the 5? g" 239/575 i g3 like which has a gun body with a depending handle, the d 475 526 handle being hollow and having a filter unit disposed 1e zgoglsgnlrcsi..zgi -ill89 216/3 axially therein, the filter unit being spring-biased so as v 448 to eject for easy removal.
1 Claim, 2 Drawing Figures Patented July 3, 1973 3,743,188-
SPRAY GUN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to spray devices, more particularly to a spray gun for paint or the like.
2. Prior Art Devices for the atomization of fluids, particularly of paints, are well-known to the art. A class of such devices includes those which are known as spray guns having body portions with interior conduits therein and a nozzled orifice at one end, the body having a handle depending therefrom for gripping the body. A type of such spray gun has conduits in the handle communicating with conduits in the body and the bottom portion of the handle has fixtures mounted thereon for attaching the gun to a source of pressurized fluid such as paintv Thus, the fluid to be sprayed is fed to the orifice in the body through the handle.
In normal prior art spray guns of this type, a filtering device was used intermediate the source of the pressurized fluid to be sprayed and the nozzle. Such filtration devices usually are located between the handle of the spray gun and the high-pressure conduit outside of the handle. This arrangement disadvantageously complicates the operation of the spray gun and, in addition, it creates additional expense in the manufacture of the gun and spray assembly including, for example, the requirement of additional threaded connections to be sealed against high pressure between the high-pressure conduit and the filter and/or between the filter and the handle.
SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art and provides for a filter unit which is inserted into a hollow section in the handle of the spray gun.
Preferably, the handle has an axially extending opening therethrough, the upper end of which communicates to the interior conduits in the body, and the lower end of which is attachable to the high-pressure conduit supplying the source of pressurized spray fluid.
The hollow interior of the handle has an axially elongated tubular filter unit disposed therein and a flow pattern which forces the spray material to flow from the exterior of the tubular unit through the walls thereof to the interior, the interior being communicated to the body portion. The tubular unit may have orifices through the wall thereof and may include a filter screen therearound.
The provision of the filter unit interior of the handle eliminates the need for multiplicity of exterior connections and allows the high-pressure conduit to be attached directly to the handle. This increases the ease with which the spray gun can be handled while at the same time reduces the cost of producing the spray gun.
In the preferred embodiment, the filter unit is easily removable from the handle and includes a spring member urging the filter unit out of the handle for removability therefrom.
In one embodiment, the handle is removably connected through a fluid tight joint to the body of the spray gun and the filter unit may be removed by unthreading the handle from the gun.
In another embodiment, the handle is permanently attached to the body and the filter is removed through the free end of the handle which is detachably connected to the high-pressure conduit. The detachable connection can then be either a threaded projection on the handle which is threadable into a threaded recess on the gun body, or can be by way ofa threaded projection on the gun body threaded into a recess in the handle.
In both embodiments, the spring is tensioned by the assembly such that when the assembly is disconnected, the filter will be pushed partially out of the handle.
It is therefore an object of this invention to provide an improved spray gun.
It is a further object of this invention to provide a spray gun of the type receiving a pressured source of fluid to be sprayed, the gun not requiring an additional source of pressured air, the connection from the source of pressured fluid to the spray gun being through the handle of the gun and the handle including a filter element.
It is another and more particular object of this invention to provide a spray gun having a filter element in the handle thereof, the element being removable.
It is a more specific object of this invention to provide a spray gun of the type described having a conduit through the handle, the conduit including a filter element, the filter element being removable from the conduit upon disassembly of the operative connection from the conduit to the spray body.
It is yet another object of this invention to provide a spray gun having a disassembleable handle, the handle having a conduit therein and the conduit containing a removable filter element.
BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
FIG. 1 is a side elevational view, partially in cross section, of a spray gun equipped with an in-handle filter element according to this invention.
FIG. 2 is a view similar to FIG. 1 illustrating another embodiment of the spray gun of this invention, having a detachable handle.
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a spray gun of the type nonnally used to spray paint or the like. The gun receives a supply of pressurized fluid to be sprayed and atomizes the fluid to a mist which is ejected from the spraying orifice of the gun. This is done without requiring an air compressor to supply pressurized air to the gun.
The spray gun includes a body portion 1, a handle portion 2, and a trigger or actuating lever 3 which is pivotably attached to the main body portion 1.
The handle 2 depends from the main body portion 1 and in the embodiment illustrated in FIG. 1 is integral therewith. The handle has an axial channel or bore 4 extending from the free end of the handle to the body portion.
The channel 4 contains therein a tubular filter element 5 which may have a filter screen 6 therearound. The filter element is a cartridge which is insertable as a unit into the channel 4 from the free end of the handle.
The filter cartridge has a hollow interior channel 7 and orifices around the periphery thereof and along the length thereof communicating the outer diameter to the channel 7. The lower end of the channel 7 is closed by an end plug a on the element 5.
The cartridge is maintained in the handle by abutment with a removable threaded connection 8 to a conduit 9 which is the source of the high-pressure paint or other fluid to be sprayed.
At the innermost end of the cartridge, the outer diameter is tapered as at 13 and extends into a smaller diameter counterbore 14 at the end of the channel 4. The counterbore 14 is communicated via a conduit 15 into the internal conduits of the main body portion 1 of the spray gun. The seating of the tapered portion 13 in the counterbore 14 centers the tubular filter element 5 in the channel 4 so that fluids may flow all around the screen 6 for the full length thereof. A compression spring 12 is entrapped between the botton of the counterbore l4 and an internal abutment portion of the interior channel 7. The interior abutment portion may be formed by having a larger diameter portion 11 of the channel 7 extending to the end 13.
It can be seen that when the threaded connection 8 is removed from the spray gun, the spring 12 will urge the filter cartridge out of the free end of the handle 2 to a point where it can be grasped and removed from the handle.
FIG. 2 illustrates a modified form of the invention wherein the handle 17 is itself detachably connected to the main body portion 1 of the spray gun. The handle has a threaded end, which may have a reduced diameter, which is threaded into an internally threaded opening in the main body portion. Alternatively, of course, it is to be understood that the connection could be the reverse, that the main body portion could have an externally threaded projection while the handle had an internally threaded end threaded onto the projection of ter unit as illustrated, and serves to bias the filter element out of the top end or threaded end of the handle.
The coupling 8 connects the high-pressure conduitto the free end of the handle and if desired, the free end of the handle can have a threaded boss 8a closing the bore 4 and receiving the connection 8.
In order to provide sealing between the threaded connection of the handle to the main body, the outer diameter of the reduced diameter threaded end of the handle has a conical shape as at 19 and a seal ring 20 is received in the threaded bore of the main body portion. The cone angle of the outer diameter surface at 19 is selected so that upon screwing of the handle onto the main body portion, a wedging effect is produced between the conical surface and the sealing ring so that the handle can be screwed onto the gun body without the aid of a tool while at the same time maintaining adequate sealing sufficient to prevent leakage at the main body-handle connection.
As can be seen from the above, both embodiments provide an internal filter element entrapped in a bore in the handle of the spray gun, the element including a spring urging the filter element out of the handle for easy removability. In both cases, the spring element is compressed when the handle opening is closed, in the first embodiment by a removable coupling 8 for the high-pressure conduit and in the second embodiment by a handle removable from the main body portion of the gun.
Although the teachings of my invention have herein been discussed with reference to specific theories and embodiments and although illustrative means for accomplishing explained results have been described, it is to be understood that these are by way of illustration only and that others may wish to utilize our invention in different designs or applications.
1. A spray gun comprising: a body, a hollow handle depending from the body, a conduit coupling on the free end of the handle to feed fluid to be sprayed into the handle, an elongated tubular filter in the handle having an open end seated in the body to center the filter in the handle for receiving fluids along the length of the handle and to flow fluid inside the filter to the body, a spring acting on the filter in a direction to eject it from the handle, and means loading said filter to seal the open end of the filter to the body.
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