US 2708600 A
Description (OCR text may contain errors)
United States Patent O SPRAYING GUN (Iscar Froidevaux, Antony, France, assigner to Socit dite: Tecalemit, Societe Anonyme, Paris, France Application November 28, 1952, Serial No. 323,080
.Claims priority, application France December 19, 1951 2 Claims. (Cl. 299-86) My invention relates to a spraying gun which is absolutely fool-proof fory the reason that no parts are included in its construction which are liable to suffer from careless handling of the gun and which is particularly suitable for spraying such viscous and sticky materials as mastics or bitumens for the purpose e. g. of silencing parts liable to vibrate.
With this end in view, my spraying gun is only composed of the few following parts:'a barrel which provides a reservoir for a charge of the material to be sprayed; a hollow tie rod which extends axially through said barrel and which is formed at either end thereof with an external screwthread; a handle formed with a side boss and bored with a thorough longitudinal channel communicating at its one end with a line for the supply of a compressed fiuid, at intermediate points with cross channels leading through said boss respectively to the channel in said hollow cross tie and into the reservoir in said barrel and at its opposite end with a vent; a head formed with a rim providing a socket for the outer end of said barrel, tapped with a hole for the reception of the outer end of said hollow tie rod and with two further holes in which a filling nipple and the spraying device proper are screwed respectively and an idle piston slidably fitted both in said barrel and on said L said choke is a hole in which a vent plug is received the bore of which is larger than that of the choke, the combination of the choke with the vent providing an ejector in which the former acts as the jet and the latter as the nozzle. The said ejector does not partake of the spraying action proper, its only purpose being to assist the release of the pressure applied formerly to the rear side of the idle piston and even to create a slight vacuum as soon as the supply of pressure fiuid is cut ofi.
Further advantages and features of my invention will be evidenced in the following specification, reference being had to the appended drawing in which a spraying gun according to my invention is illustrated in longitudinal sectional view.
In the drawing, 1 designates the gun barrel, which provides a reservoir for the material to be sprayed, 2 the side boss solid with the gun handle 3 while 4 designates the head which carries the filling nipple and the spraying device proper. I v
The parts 1, 2 and 4 are tied together by means of an axial hollow rod 5 which has screwthreaded ends en gaged in holes tapped in the boss and the head respectively; joint rings 6, 7 are interposed between either end of the barrel 1 and the boss 2 and the head 4 respectively.
Before the set of parts are assembled an idle piston 8 is made a sliding fit in the barrel 1 and on the hollow tie rod 5. f
Bored in handle 3 is a channel 9 which through a cross channel 10 communicates with the channel 11 in the tie rod 5. Beyond thecross channel 10 the axial channel 9 is formed with a choke 12-which communicates through a further cross `channel 13'with the reservoir in barrel 1.
Beyond said cross channel 13 said channel 9 andI choke 12 extend in a vent channel 14. t l l y l Channels 12 and 14 are so arranged relative to each other and to cross channel 13 as toperform the function of an ejector in which 12 acts as the jet and 14 as the nozzle. l
The purpose of such an ejector 12-14 is. to prevent any pressure being exerted upon the idle piston as long as no material is to be sprayed and to ensure a quick release of the pressure in the reservoir as soon as the spraying process ceases.
Tapped through head 4 are a hole 15 for the reception of a filling nipple 17 and a hole 16 for the reception of a delivery nozzle 1S with a taper end 19.
The head 4 is formed with a nipple 20 which is screwthreaded at 21 for the connection of a screw cap 22 delimited inside by a conical surface 23 corresponding to the taper of the delivery nozzle 18.
Practically, the cap 22 is so dimensioned that when screwed home on the threaded portion of nipple 20 the annular slit between the inside of 22 and the outside of 23 a sufficient stream of the fiuid=under pressure `is allowed to rush therethrough to ensure perfect atomization of the material in the reservoir. Nevertheless, it is always possible to increase the sectional area of the slit by unscrewing the cap 22 to a limited extent.
The channel 11 in tie rod 5 communicates through a port with an annular chamber 24 surrounding the nozzle 18 in the bore in nipple 20, from which chamber 24 the pressure fiuid is deflected by fillets 18a milled in the skirt of nozzle 18 towards the annular slit delimited by the conical surfaces 19 and 23.
The nipple 17 is designed to allow the reservoir 1 being refilled from the conventional pump pail and can be closed with the aid of a screw plug 25 provided with a knurled head and with a tail piece 26 of special design to serve for the purpose explained as follows:
The bore in the nozzle 18 is formed with a restricted outlet 2'7 for the reception, before the filling of the reservoir is started, of said tail portion 26 of screw plug 25.
My spraying gun operates as follows:
For the filling of the reservoir 1 the screw plug 25 is taken away and fitted with its tail portion 26 into the orifice 27 of nozzle 18, whereby the gun is closed at its delivery end and the reservoir 1 can be refilled.
ln proportion as material is forced into it the idle piston 8 therein is driven backwards until it is stopped by the boss 2 in which the barrel 1 is socketed, when the reservoir is full.
Thereafter, the plug 25 is pulled out of the nozzle 18 and screwed again into the filling nipple 17.
ln spraying out the material in reservoir 1 the pressure fluid is switched into the channel 9 in the handle 3. With the orifice of ejector 12e-14 open the working uid cannot act upon the idle piston 8 since it is allowed to escape to the outside on the one hand through cross channel 10, axial channel 11, chamber 24 and the annular slit between 19 and 23 and on the other hand through ejector 12-14 while creating a slight vacuum on the back side of the idle piston 8.
It is only necessary for the operator to close the vent 14 with his thumb to set the ejector out of action, as a result of which the uid pressure is caused to act upon the back side of the idle piston 8 and thereby to force the materialin the reservoir through the nozzle 27.
The worm of material thus forced out is caught by the jet of pressure fluid expelled through the slit between the conical surfaces 19, 23 (see angle a) and is pro jected thereby as a conical spray (see angle It will be understood easily that given the pressure of the ejecting fluid it is possible to control the amount of material ejected simply by more or less uncovering the-vent 14.
The outilow of material is stopped altogether as soon as the vent 14 is completely uncovered since the ejector 12-14 will immediately become once more effective to release the pressure prevailing in the reservoir 1 and furthermore to create a slight vacuum within the same.
It will be appreciated that the gun can successfully be used for spraying other materials, e. g. cement wash or like coating materials to be sprayed onto walls or similar surfaces.
' What I claim is:
l. A spraying gun for the application of viscous mathrough said boss to the channel in said hollow cross tie and a second cross channel communicating with said longitudinal channel and leading into the reservoir in said barrel, and said longitudinal channel being formed at its opposite end with a vent with an opening closable by the linger of the operator of the gun, a head formed '-1- with a rim providing a socket for the outer end of said barrel, said head being tapped with a hole for the reception of the outer end of said hollow tie rod and with two additional holes, a lling nipple received in one of said holes, a spraying unit received in the other of said holes, and an idle piston slidably fitted in said barrel and on said hollow tie rod.
2. A spraying gun for the application of viscous materials which comprises a barrel which provides a reservoir for a charge of the material to be sprayed, a hollow tie rod extending axially through said barrel and formed at each end with an external screwthread, a handle member formed with a side boss receiving one end of said tie rod and bored with a through longitudinal channel communicating at one end with a line for the supply of a compressed fluid, a cross channel communicating with said longitudinal channel and leading through said boss to the channel in said hollow cross tie and a second cross channel communicating with said longitudinal channel and leading into the reservoir in said barrel, and said longitudinal channel being formed at its opposite end with a vent with an opening closable by the finger of the operator of the gun, said longi-l tudinal channel being choked opposite the vent, a head formed with a rim providing av socket for the outer end of said barrel, said head being tapped with a hole for the reception of the outer end of said hollow tie rod and with two additional holes, a filling nipple closed by a screw plug received in one of said holes, a spraying unit received in the other of said holes, said spraying unit including a cone-tipped nozzle for the discharge of the materiali enclosed in the barrel, a cone-tipped cap drilled through its apex with an outlet and delimiting an annular chamber surrounding the conical tip of the nozzle and communicating through the head with the channel in the hollow tie rod, and an idle piston slidably fitted in said barrel and on said hollow tie rod.
References Cited in the iile of this patent UNITED STATES PATENTS 716,910 Lubbecke Dec. 30, 1902 l1,090,119 Overbeke June 18, 1912 1,578,944 Wilkinson Mar. 30, 1926 1,590,430 Erby lune 29, 1926