US 2656217 A
Description (OCR text may contain errors)
Oct. 20, 1953 O 2,656,217
LOW FRESSURE SPRAY GUN Filed Jan. 31, 1951 mvergom ANDRE ROCHE.
Patented Oct. 20, 1953 LOW-PRESSURE SPRAY GUN Andi- Roche, Aix-en-Provence, France Application January 31, 1951, Serial No. 208,778 In France July 27, 1950 1 Claim.
The application of paints by spraying offers multiple advantages from the point of view of saving of paint and perfection of covering.
In spite of the pressure of three or four kilogrammes per square centimeter commonly employed, only paints of low density and viscosity can generally be thus applied. Tar-like substances, red lead and the like are more difficult to spray.
The object of the invention consists in the provision of a spraying apparatus which overcomes the above mentioned inconveniences and permits the use or low pressures equal to or not exceeding two hundred grammes per square centimeter for the spraying and spreading of paints of all viscosities, including tars.
The accompanying drawing shows a form of construction of spray gun according to the invention in longitudinal section.
The spray gun consists of a gun body having at its lower part an air inlet conduit l. The external walls 2, 3 are shaped to form a butt.
This conduit l emerges into the upper horizontal part of the body having cylindrical passage means 4 extended by an outlet nozzle 5 with double distribution channels 6 and l for the spraying fluid. A boss 8 on the body carries a pivoted two-arm operating lever actuating, by a push-rod Ill, an operating rod II mounted on a spindle l2 and terminated by a fork 13.
The rear part of the passage 4 receives a sleeve or ring it with a hermetically sealed adjusting screw l5, the central cavity l6 of which serves to guide the longitudinal obturating rod IT with air cular abutment l 8 and spring IS. The front part Ila of the rod ll enters an air-tight conduit 24) and forms therewith an outlet valve communicating with an outlet conduit 22 in the body, said valve being urged into closed position by its spring loading. On the upper part of the body is secured a circular support 23 having an airtight joint and carrying an hermetically sealed removable reservoir 25 retained by known tightening means. The conduit 22 opens into the lower part of the reservoir, and serves to feed the sprayed liquid to the outlet valve.
A conduit 25 communicating with the passage 4 and the interior of the reservoir has an inlet needle-valve 26 actuated by the arm 21 of the operating handle 9, a return spring 23 being arranged between the ring 29 and the seat of the needle-valve to urge the valve 26 into open position.
Th reservoir 24, is filled in the normal way and afterwards fixed on to the support 23. The
whole apparatus is then raised to its position for use. The low pressure compressed air enters the apparatus through the conduit I in the direction of the arrow A and is directed through the passage 4 towards the nozzle 5 and channels 6 and 1.
By pressing the operating handle in the direction of the arrow B a simultaneous movement of both valve means is caused. Firstly, by the aation of the push-rod Hi, the operating rod l 1 acts, by means of its fork is, on the circular boss 5 8 of the rod l1 and moves the latter to open the outlet valve.
The spring l9 always tends, when the handle is released, to return the needle Ila on to its seat in the closed position and simultaneously force the handle into rest position to close the inlet valve. By this same displacement, the operating handle 9, through its arm 2'1, allows the disengagement of the needle 26 from its seat 29 in the direction of the arrow D by the spring 28.
The air under pressure contained in the passage 4 then enters through the conduit 25 and is distributed in the upper part of the reservoir 24. The latter is subjected to a pressure F identical to that of the spraying fluid, and the sprayed liquid therein is propelled towards the valve conduit 26.
The pressure of the spraying fluid is thus added to the weight of the sprayed liquid.
In a spray gun of the kind including a gun body having passage means and an outlet nozzle for the spraying fluid, a reservoir for the liquid to be sprayed mounted on the gun body, an outlet valve for the sprayed liquid arranged in the passage means and communicating with the reservoir, a longitudinally slidable valve stem for the outlet valve arranged in the passage means and spring-urged into closed position, an inlet valve for the reservoir arranged on the body and forming a communication between the passage means and the interior of the reservoir, and a movable valve member for the inlet valve spring-urged into open position; the features of a two-arm lever pivoted intermediate its ends to the gun body and serving as an operating handle, an abutment member on the outlet valve stem, an oper ating rod movably mounted in the gun body and arranged to contact said abutment member for longitudinal movement of the stem, and a push rod carried by the operating rod, one arm of the pivoted two-arm lever being arranged to bear against the movable inlet valve member and the other arm of th two-arm lever being arranged to bear against the push rod for control of the outlet valve stem, whereby movement of the twoarm lever permits simultaneous operating of the inlet and outlet valves.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,777,925 Kollmann 1 Oct. 7, 930 887,969 Tracy Nov. 15, 1932 FOREIGN PATENTS Number Country 9 Date 386,101 Great Britain Jan. 12, 1933 910,416 France Jan. 28, 1946