US 3899134 A
A piston pump spray gun with a detachable container for fluids, such as paint, to be sprayed is provided with a removable die cast metal or injection molded plastics one-piece pump housing and lid or cover for the container with the pump housing portion molded or cast around a hard metal cylinder sleeve for the piston and passages connecting the interior of the sleeve with the container without requiring seals to feed liquid from the container to the pump and for draining liquid back to the container. The one-piece part together with a piston operating in the cylinder sleeve is easily mounted on and removed from the main body of the spray gun by means of a single securing ring rotatable on the pump housing portion and threaded in the front of the main body of the gun. The one-piece molding or casting with its integrated hard metal cylinder eliminates leakage paths, reduces manufacturing costs, and facilitates replacement or repair of worn or broken parts.
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Description (OCR text may contain errors)
United States Patent Wagner Aug. 12, 1975 SPRAY GUN Primary ExaminerM. Henson Wood, Jr.  Inventor: Josef Wagner, Markdorfer Strasse Assmam m M l Mar 185, 799 Friedrichshafen 2 Attorney, Agent, or FzrmH1ll, Gross, Simpson, Van Germany Santen, Steadman, Chiara & Simpson 22 Filed: June 13, 1974 v 21 1 Appl. No.: 478,856
 Foreign Application Priority Data [5 7 ABSTRACT A piston pump spray gun with a detachable container for fluids, such as paint, to be sprayed is provided with a removable di cast metal or injection molded plastics one-piece pump housing and lid or cover for the container with the pump housing portion molded or cast around a hard metal cylinder sleeve for the piston and passages connecting the interior of the sleeve with the container without requiring seals to feed liquid from the container to the pump and for draining liquid back to the container. The one-piece part together with a piston operating in the cylinder sleeve is easily mounted on and removed from the main body of the spray gun by means of a single securing ring rotatable on the pump housing portion and threaded in the front of the main body of the gun. The one-piece molding or casting with it's integrated hard metal cylinder eliminates leakage paths, reduces manufacturing costs, and facilitates replacement or repair of worn or broken parts.
10 Claims, 3 Drawing Figures PATENTED 3.899.134
SHEET 1 FIG] PATENTEBAUB1 21975 3, 899, 1 34 SHEEI 2 SPRAY GUN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the art of spray guns and particularly to a simplified, inexpensive one-piece molded or cast part for a piston pump supply container carrying spray gun surrounding and integrating a hard metal cylinder sleeve for the piston and providing a mounting cover or lid for the container. Specifically, the one-piece part of this invention provides a pump housing portion molded or cast around a cylinder sleeve in which the piston operates and a depending cover or lid portion into which is threaded a container for material to be sprayed and having leak proof passages conveying fluid between the container and sleeve without the aid of seals. The piston housing portion of the part carries a locking ring which is threaded into the spray gun housing for securing the part to the spray gun.
2. Prior Art Piston pump paint spray guns have heretofore been provided with piston cylinders or sleeves inserted in a bore or recess in the spray gun housing and secured therein by a threaded pin. Such constructions required seals between the cylinder sleeve, the bore in which the sleeve was received, and the structural part providing the bore. These seals had to be seated in recesses and not only were extra seal parts required, but additional machining was necessary. Then when the cylinder sleeve was replaced, satisfactory rescaling was frequently not obtained so that air would be sucked into the piston pump and feed performance would be impaired.
SUMMARY OF THIS INVENTION The present invention now eliminates the heretofore required seals and extra machining operations for piston pump spray guns by molding or die casting the pump housing around the cylinder sleeve for the piston and integrating this housing with a depending lid or cover for the spray gun supply container. The onepiece pump housing and lid molded or cast part has a hollow stem receiving a suction tube depending into the container which registers with an aperture in the cylinder sleeve to feed the liquid to be sprayed to the pump and also has a passageway communicating with a chamber in the sleeve to drain liquid back to the container. Machining of the passages and seals between these passages and the cylinder sleeve are not needed because the pump housing part is tightly molded around and integrated with the cylinder sleeve.
The one-piece molded or die cast part is detachably mounted on the main housing of the spray gun with the pump housing portion of the part having a cylindrical sleeve fitting into a bore of the gun housing and the lid portion of the part underlying the housing while a neck connecting the pump housing and lid portions of the part fits in an open front recess in the bottom of the housing bore. A single locking ring on the pump housing portion is threaded into the bore of the gun housing to secure the part in position in the gun housing. A spray head is threaded on the outer end of the pump housing portion of the part and an outlet valve slidable in the pump housing portion seats against an end of the cylinder sleeve while a piston slidable in the sleeve is reciprocated by driving means in the gun housing to suck liquid from the container into the cylinder sleeve and to discharge the liquid from the sleeve through the outlet valve to the spray nozzle.
It is then an object of this invention to simplify and reduce the cost of piston pump spray guns by molding or die casting a pump housing around a cylinder sleeve for the pump.
Another object of the invention is to eliminate heretofore required seals between the pump housing and cylinder sleeve of a piston pump spray gun.
Another object of the invention is to provide a spray gun with a removable molded or die cast part housing a piston pump assembly and suspending a supply container from the gun.
A further object of the invention is to provide a spray gun for the atomization of liquids by means of a piston pump driven from an alternating current oscillating magnet and having a supply container suspended therefrom wherein a one-piece molded or cast part provides the pump housing and the lid for the supply container and is removable from the gun by manipulation of a single locking member.
Another object of the invention is to provide a piston pump spray gun having a housing with an open front bore and an open front bottom recess detachably receiving a one-piece part including a pump housing fitting said bore, a neck fitting said recess, and a lid suspended from said neck underlying the gun housing to support and close the top of a supply container.
Other and further objects of this invention will become apparent to those skilled in this art from the following detailed description of the annexed sheets of drawings which by way of example only, illustrate one embodiment of the invention.
IN THE DRAWINGS FIG. 1 is a side elevational view of a spray gun provided with the pump part of this invention and shown partly in vertical section;
FIG. 2 is an enlarged vertical sectional view of the pump and container lid part provided for the spray gun of FIG. 1 according to this invention; and
FIG. 3 is a front end elevational view with parts in transverse section of the spray gun of FIG. I.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT The spray gun I of FIG. 1 is especially suitable for paint spraying and includes a gun housing 2 in which is mounted an electromagnet 3 with an oscillating armature 4 actuated by alternating current from a switch 5 in a depending handle portion of the housing 2. A supply container 6 is removably suspended from the housing 2 and feeds liquids, such as paint, through a suction tube 7 suspended from a cover or lid 8 for the container 6. The lid 8 is a portion of a one-piece injection molded plastics material or die cast metal part suspended from a bore 9 of the gun housing 2 and has a sleeve-like pump housing portion 10 removably seated in the bore 9 and molded or cast around a hard metal cylinder sleeve 11.
As shown in FIG. 1, a piston 12 is slidably mounted in the cylinder 11 and a pumping chamber 13 is provided ahead of this piston 12. A return spring 14 in the bore 9 of the gun housing 2 biases the piston 12 against the armature 4.
municates the outlet valve with the spray nozzle 16.
The lid or cover portion 8 and the pump housing portion 10 of the one-piece molded or die cast part are joined by a neck 21 fitting snugly in an open front bottom recess 22 in the bore 9 of the gun housing 2 and a flat bottom wall 23 of the gun housing receives the flat top of the cover or lid snugly thereagainst with the periphery of the top of the lid being bottomed against a shoulder 24 acting as a stop member on the bottom of the gun housing 2.
A hollow stem 25 depends from the lid and has a tapered bore therethrough receiving the suction tube 7. A passageway 26 is also provided through the lid and neck 21 adjacent this stem 25. The hollow interior of the stem 25 is connected through an aperture 27 in the cylinder sleeve 11 with the pumping chamber 13 of the sleeve. An opening 28 in the sleeve 11 joins the passageway 26 with an enlarged internal collection cham ber 29 in the sleeve 11.
The sleeve has an annular recess 30 therearound filled with plastics or metal material from the molding or die casting operation to integrally lock the sleeve with the pump housing portion 10. The bore 9 of the gun housing 2 has an internal shoulder 31 forming an abutment for an annular collar 32 integral with the pump housing portion 10 to limit the insertion of this pump housing portion 10 in the bore 9.
A securing ring 33 rotatable on the outer end of the pump housing 10 is screwed into an internal thread 34 in the outer end of the bore 9 against the collar 32 to secure the collar against the shoulder 31. Thus the pump housing 10 is tightly anchored in the bore 9.
The spray nozzle 16 is threaded on the projecting front end portion 35 of the pump housing 10 which has external threads 36 for receiving the internal threads of the nozzle 16.
Container 6 has an externally threaded neck threaded in the internal thread 37 of the cover or lid 8, to provide a liquid-tight connection between the container and cover so that liquid will not spill out of the container even when the spray gun has fallen over or is laid down.
In operation of the spray gun I, the handle portion of the gun housing 2 is manually gripped and the switch 5 is depressed by the index finger of the gripping hand whereupon the electromagnet 3 will be energized to oscillate the armature 4 thereby driving the piston 12 to the left as viewed in FIG. 1 and displacing liquid in the pumping chamber 13 to unseat the outlet valve 15 and discharge the liquid through the nozzle 16. On this pressure stroke of the piston 12, the inlet aperture 27 is closed by the piston. As the armature 4 swings to the right, the spring 14 causes the piston to follow the armature thereby retracting the piston to the right on a suction stroke closing the outlet valve 15, uncovering the aperture 27 and sucking liquid from the container 6 through the tube 7 into the pumping chamber 13. Liquid finding its way between the piston 12 and the cylinder 1 l is collected in the enlarged collection chamber 29 and drained back to the container 6 through the opening 28 and the passageway 26.
When it is desired to replace or repair the piston pump or any of its components, the securing ring 33 is unthreaded from the threads 34 and the entire pump assembly is easily pulled forwardly out of the gun housing since the pump housing, and the lid or cover 8 are all part of the same one-piece member. Then it is easy to remove the piston, the valve, and the spring of the pump assembly for repair, or replacement. Cleaning of the pump components is, of course, also facilitated.
Therefore, from the above descriptions it will be clearly understood that this invention provides a simplifled, inexpensive pump assembly for piston pump spray guns which is easily mounted in and removed from the spray gun housing and eliminates heretofore necessary seals and machining operations. The one-piece molded plastics or metal die cast part of this invention for mounting the pump components and suspending the supply container for the gun is inexpensive and easily formed around a hard wear resisting cylinder sleeve for the piston by injection molding, metal spray die casting and the like forming operations.
I claim as my invention:
l. A piston pump spray gun which comprises a housing having a depending handle, an electromagnetic motor with an oscillating armature in said housing, a switch in said handle controlling current flow to said motor, said housing having a bore communicating with said armature and with the front of the housing, a onepiece part having a pump housing sleeve fitting said bore with a hard metal cylinder sleeve therein, a piston slidable in said cylinder sleeve, a spring in said bore of the gun housing biasing said piston against said oscillating armature of said motor, an outlet valve in said pump housing sleeve portion bottomed against said cylinder sleeve, a spray nozzle on the outer end of said pump housing sleeve receiving fluid from said outlet valve, a locking ring rotatable on said pump housing sleeve threaded in said gun housing bore against said pump housing sleeve for securing the sleeve in the bore, said sleeve having a depending neck and a container cover suspended on said neck, said gun housing having a recess receiving said neck and a bottom wall receiving said cover, a removable liquids container suspended from said cover, said neck and cover having passages therethrough connecting the interior of the container with the interior of said cylinder sleeve, a suction tube extending from one of said passages to the bottom of said container and a collection chamber in said cylinder sleeve communicating with the other of said passages whereby said spring and said armature will reciprocate said piston to suck liquid from said container through said tube into said cylinder sleeve and will discharge the liquid in the sleeve past said outlet valve to said spray nozzle and said part is easily mounted in and removed from the bore and recess of said gun housing by manipulation of said locking ring.
2. The spray gun of claim 1 wherein said one piece part has a depending hollow stem receiving said suction tube.
3. The spray gun of claim 1 wherein the bore of the gun housing is cylindrical, the pump housing sleeve portion of the part snugly fits said bore and the recess of the gun housing is open at the front and snugly receives the neck of said part.
4. The spray gun of claim 1 wherein the pump housing portion of said part is integrally molded around said sleeve and said sleeve has an external groove receiving a portion of the molded pump housing portion.
5. in a piston pump spray gun having a housing, a motor in the housing for driving the piston pump and a depending container for material to be sprayed suspended from the housing, the improvements of a onepiece part having a pump housing portion fitting in said spray gun housing and integrally molded around a hard metal cylinder sleeve for the piston of the piston pump and a cover portion depending therefrom supporting said container with passageways connecting the container with the interior of the cylinder sleeve, and a locking means detachably securing said one-piece part to said spray gun housing.
6. The spray gun of claim 5 wherein the pump housing portion of the one-piece part is cylindrical and sized for snug fitting in the spray gun housing and a spray nozzle is secured on the end of said pump housing cylindrical portion.
7. The spray gun of claim 5 wherein the locking means is rotatably mounted on the pump housing portion of the one-piece part.
8. in a spray gun of the type having a motor housing, a motor in the housing, a piston pump driven by the motor in the housing and a container suspended from the housing to supply liquid to be sprayed to the pump together with a spray nozzle discharging the liquid from the pump, the improvements which comprise said housing having a bore opening adjacent said nozzle, a one-piece part having a portion removably insertable in said bore of the housing and molded around a cylinder sleeve forming the cylinder for the piston pump together with a cover portion depending therefrom supporting the container for the liquid to be sprayed and having passages connecting the container with the cylinder sleeve, and a locking ring rotatable on the onepiece part threaded in said bore of the housing releasably securing said one-piece part to said housing.
9. The spray gun of claim 8 wherein the portion of the one-piece part insertable in the bore of the housing has a front end projecting from the housing and a spray nozzle is removably secured on said front end.
10. A one-piece cast or molded part for removable attachment to the housing of a spray gun having a supply container which comprises a member having a sleeve portion insertable in a spray gun housing providing a pump housing and surrounding a pump cylinder sleeve in integrated relationship therewith together with a depending neck portion suspending a lid adapted to receive and support the supply container for the gun, said member having passages therethrough joining the interior of the cylinder sleeve with the interior of said lid, and a locking member on said one-piece part for detachably uniting the part to the spray gun.