MULTI-PURPOSE SPRAY GUN

Abstract: Hand held compressed air gun for spraying particulate materials comprising a hand held stock (2) supporting a tubular housing (4), a barrel member (60) having a breech end rotatably supported in the tubular housing, a handle (72) attached to the barrel (60) forwardly of the housing whereby the latter may be manually rotated relative to the tubular housing, a hopper for particulate material mounted on the tubular housing above an opening defined therein, the breech end of the barrel defining a further opening in the side wall of the barrel (68) whereby on rotation of the barrel (60) there is a continuously variable degree of coincidence between the opening in the breech end of the barrel (68) and the opening in the breech block, and an air supply pipe extending axially (62) through the breech block (4) and the breech end of the barrel to a nozzle adjacent the opening therein and directed towards the nozzle end of the barrel, whereby to eject material into and out the barrel (60) from the hopper, being said barrel interchangeable with other barrels differently conceived.

Description: Multi-Purpose Spray Gun This invontion is directed to compressed air operated halls held spray guns for applying fit he6 to walls arid similar surfaces. It is known to apply plaster, stucco and other textured wall finishes using hand held spray guns operated by compressed air. A typical spray gun used for this purpose is that sold by Bliss & BR< Laughlin Industries rider the trade mark GOLDBLATT. These spray gutis are essezitially adaptations of the compressed air operated spray uns utilized to spray paints and lacquers, modified so as to be able to handle sprayable materials of various textures and consistencies, Such guns are inevitably prone to occasional blockage, jamming and damage by the material being sprayed, and since it is often impracticable to dismantle the gun to correct such problems on site, all adequate supply of. spare, guns must be available. Moreover, such gulls are neither designed for llor capable of spraying the coarse particulate materials used as a surface layer on some types of wall finish such as pebble-dash. It; is also known to provide fluid operated guns to project a stream of sand or grit for cleaning azid removing previous finishes from walls by sand-blasting, but these are clearly not suited for applyilig particulate material to an unhardened wall finish, nor evezi if adapted for this purpose would they have the versatility to handle a wide range of particulate materials with a readily controllable rate of application. Moreover most such blastizig guns require a fairly sophisticated system for delivering the particulate material. The applicant is seeking to provide an air operatedgun which is adaptable not only to applying particulate material to plaster. but will also apply the plaster itself, whilst being of a construction which not only minimizes the risk of jamming or blockage but permits ready disassembly on site should a problem occur. Accordillg to the illventioll, there is provided a hand held compressed air spray gun comprising a stock member supportizzg a tubular housing, defiziiizg a uniform cylindrical bore having frotlt and rear ends and aiz aperture in the wall of the bore near its front end, and a trigger mechaziism external to the tubular housing, a breech block secured in the rear end of the bore, at least one barrel assembly including a cylindrical barrel receivable in the front end of the bore, said barrel defining all opening at a muzzle end aud air aperture ill a cylindrical wall of the barrel axially adjacent the aperture in the tubular housing, an air pipe extending axially relative to the barrel from a coiizzectiozz at its rear end for coupling to a source of compressed air forwardly through a breech end of the barrel and terminating in a nozzle within the barrel, means releasably couplizig the rear end of the air pipe to the trigger mechanism when the barrel is located ill the bore so that the rear end of the air pipe extends rearwardly through a bore in the breech block, whereby to retail the barrel assembly ill thc housing. This provides a structure which is easily dismantled and cleaned, silica the trigger mechanism is wholly external to the barrel, alld the parts exposed to the material to be sprayed are housed ill a uniform cylindrical bore from which thay chill readily be removed. The barrel assembly can readily be charged to suit differellt materials azid different modes of operatioll. Differunt types of barrel assembly may be used, preferably interchangcobly. In one type of assembly the means coupling the pipe to the barrelis such ad to restrain axial mov ement of the pipe relative to the barrel, whilst permitting rotational movement of the barrel relative to the tubular housing, arid wherein the barrel is provided with a handle for the manual application of rotatiollal movement thereto whereby to adjust the degree of coincidence between the aperture in the barrel and the aperture in the housing and to control the passage of material from the hopper into the barrel for entrainment by air passed through the pipe. In another type, the means coupling the pipe to the barrel is such as to permit relative axial movement of the pipe relative to the barrel, and all aperture plate is located at the. front elld of the barrel, the nozzle of the pipe having a normal position closing an aperture of the aperture plate, the trigger mechanism when coupled to the rear end of the air pipe beillg operative. to move the latter axially so that the nozzle moves between its normal position and a position ward of the aperture, whereby material entering the barrel from the hopper may be entrained by air passed through the pipe. The invention also extends to a hand held compressed air gun for spraying particulate materials comprising a hand held stock supporting a tubular housing, a barrel member having a breech end. rotatably supported in the tubular housing, a handle attached to the barrel forwardly of the housing whereby the latter may be manually rotated relative to the tubular housing, a hopper for particulate material mounted on the tubular housing above an opening defined therein, the breech end of the barrel defining a further opening in the side wall of the barrel whereby on rotation of the barrel there is a continuously variable degree of coijicideijce betweela the opening ill the breech end of the barrel and the opening ill the breech block, and all air supply pipe extending axially through the breech block and the breech end of the barrel to a nozzle adjacent the opening therein arid directed towards the nozzle end of the barrel, whereby to eject material falling into the barrel from the hopper. One way of carrying out the invention is described ill detail below with reference to drawings which illustrate only olle preferred embodiment, in which : Figure 1 is a longitudinal vertical section through a preferred embodiment of- a spray gun ill accordance with the invention, showing olle of two alternate types of barrel fitted to the gun; ; Figure 2 is a a similar longitudinal vertical section, showing another alterllative type of barrel, the unchanged part of the gun being shown ill outlirie only. Accordillg to the above figures the body of the gui comprises a vertical handle or stock 2, azi open ended tubular housing 4 mounted across the top of the stock, aud a secolld tubular housing G of smaller diameter extending through the stock parallel to and beneath the first housing. The second housing, accomodates a pluziger Es passing through caps 10 and 12 screwed into the ends of the housing. A spring 14 acts between the cap 12 and a flallge 16 oii the plunger to bias it forwardly (to the left as shower in Figure 1). A trigger 18 is attached to the front end of the plunger, the plunger and trigger being biassed by the spring to assume the position shown. Pressure on the trigger tends to move the plunger rearwardly. A coupling member 20 is secured to the rear end of the plullger and is releasably clamped by a screw 22 to the rear and of an air pipe 24 which extends axially into the first tubular housing through a cylilldrical breech block 26 secured against displacement by a screw 28, The air pipe 24 is threaded at its rear end for attachment to a compressed air line. The air pipe 24 shown in Figure 1 forms part of an inter changeable assembly incorporating a cylindrical barrel 30 received iii the front part of the tubular housing. The assembly further comprises a rubber boot 32 forming a seal between the pipe 24 and the barrel 30 whilst permitting limited axial movement of the pipe relative to the barrel, which latter is clamped ii, place within the tubular housing by a screw 34 actiitg oil flallges 36 formed on a split outer end of the housing 4. The barrel 30 has a nozzle opening 38 within which an orifice plate 40 is retained by a split ring 42. A nozzle 52 screwed into the outer fetid of the pipe 24 normally closes an orifice in the orifice plate. A felt washer 54 is located between the barrel 30 azid the breech block 26. A hopper 44 is secured by a clamp 46 to a fulllel shaped opening 48 iii the top of the housing 4, which opening coincides with aji opeing 50 in the top of the barrel so that material such as plaster placed in the hopper cati enter the barrel. Whelp the air pipe 24 is connected by a hose (not shown) to a source of compressed air (not shown) and the trigger 18 is depressed, the air pipe 24 is drawn rearwardly thus withdrawing the nozzle 52 from the orifice in the orifice plate 40 so that air emerging from the nozzle etitraitis the plaster avid sprays it forwardly through the orifice according. to the collvelltiollal principle of operation of air operated gravity feed apray gulls. the other hand, as compared with conventional guns, possible causes of jamming are eliminated since the trigger mechanism and associated spring is separatcly housed from the gun proper, in which the only part is the pipe 24 with its nozzle 52. Those portions of the pipe 24 which are ill sliding colltact with other parts of the gun are of snooth cylindrical form, and outside of the barrel itself there are no voids withill the structure to become clogged or block with hardened material. The elltire barrel assembly includillg the pipe 24 can be readily removed simply by loosening the screws 22 and 34, whilst the breech block 26 is also secured by the single screw 28, and upon their removal the housing 4 presents a smooth, uniform cylindrical bore. Thus disassembly and cleaning of the gun is extremely simple and there are also advantages in manufacture since the gun parts require only a millimum of very simple and straighforward machilling operations. Upoll removing the barrel assembly comprisilig the barrel 30 and the pipe 24, this may be replaced by the alterllative assembly shown in Figure 2. This assembly also comprises a barrel 60 and a pipe 62, but is installed aiitl operated somewhat differently in order to adapt the gun for the application of solid particulate material to the surface of a previously applied matrix layer to which the particulate material adheres. The pipe 62 passes through an axial orifice in the breech end of the barrel 60, and is secured against. withdrawal from it by a rubber O-rillg 64 which also serves as a seal whilst permitting rotatioll of the barrel relative to the pipe. In order to provide for differejit locatiolls of a nozzle 66 formed at the outer end of the pipe relative to an opening 68 formed in the side of the breech end of the barrel, several peripheral grooves 70 may be provided ill the pipe 62 to provide alternative seatiiigs for the O-ring 64. The rear end of the pipe 62 is clamped by the screw 22 as before, but the O-ring 64 proveilte rcurward movement of the pipe relative to the bnrrel 60. Thus the trigger 18 and its associated mechauism is inoperative, except: us a a messes to hold the pipe 22 against movement and thus in tun to hold the breech end of the barrel 60 ill the housing 4. The O-ritlg 64 allows the barrel 60 to be rotated is the housing by means of a hand grip 72 so that the degree of coincidence of the opening 68 with the opening 48 in the housing 4 can be continuously varied from full coincidenced to zero coincidence, thus regulating the rate at which particulate material can flow from the hopper 44 into the ialterior of the barrel 60. The material so flowi'ig is ejected from the nozzle end of the barrel by air emerging from the nozzle 66 when the pipe 62 is connected to a source of compressed air. The groove 70 ill which the O-ring 64 is located is selected to provide the best results according to the particle size and density of the material to be sprayed. The gun is held with both hands, one on the stock 2, arid the other oil the hand grip 72, this second hand steadying and aiming the gun and also regulating the flow of particulate material into the barrel. As before the structure of the gull is such that it is very easily dismantled and serviced, and the risks of jamming or blockage is minimized.

Claims: Claims: 1. hand held compressed air gun for sprayilip particulate materials comprising a hand held stock (2) supporting a tubular housing (4), a barrel member (30/G0) having a breech end rotatably supported in the tubular housing (4), a halldle (72) attached to the barrel (60) forwardly of the housillg whereby the latter may be manually rotated relative to the tubular housing (4), a hopper (44) for particulate material mounted on the tubular housing (4) above an openillg defined therein, the breiich end of the barrel defining a further openilig ill the side wall of the barrel (50/68) whereby oii rotation of the barrel (60) there is a continuously variable degree of coincidence between the opeiliilg ill the breech end of the barrel (50/68) and tlie opeililig in the breech block (48), and ail air supply pipe extending axially (24/62) through the breech block (4) and the breech end of the barrel to a nozzle adjacent the upeiliilg therein and directed towards the nozzle end of the barrel, whereby to eject material into and out the barrel (60) from the hopper (44). 2. A hand held compressed air spray guli as claimed ill claim 1, comprising a stock member (2) supporting a tubular housing, defiiiiilg a uniform cylindrical bore (4) having front and rear ends and an aperture (48) ill the wall of the bore near its front end, and a trigger mechanism (18) external to the tubular housing (4), a breech block (24) secured ill the roar end of the bore, at least one barrel assembly (30/60) includillg a cylindrical barrel receivable in the front end of the bore, said barrel defining an opening (38) at a muzzle end ailed an aperture iii a cylindrical wall of the barrel (50/68) axially adjacent the aperture in the tubular housing (48), all air pipe (24) extending axially relative to the barrel (30/60) from a coiiiicetioii at its rear end fro coupling to a source of compressed air forwardly through a breech end of the barrel and terminating in a nozzle within the barrel, <RTI ID=9.5> me@ns coupling the air pipe to the barrel, and means releasably coupling (20) the rear end of the air pipe to the trigger mechanism (18) when the barrel is located ill the bore (4) so that the rear end of the air pipe extends rearwardly through a bore ill the breech block, whereby to retain the barrel assembly in the housing. 3. A gun as claimed in claim 2, wherein the means coupling the pipe to the barrel is such as to restain axial movement of the pipe relative to the barrel, whilst permitting rotational movemelst of the barrel relative to the tubular housing, and wherein the barrel is provided with a handle for the manual application of rotational movement thereto whereby to adjust the degree of coincidence between the aperture in the barrel and the aperture in the housing and to control the passage of material from the hopper into the barrel for entrainmellt hy air passed through the pipe. 4. A gun as claimed in claim 3, wherein the means coupling the pipe to the barrel is an 0-rillg (64,70) within the barrel and selectively engaged with one of a plurality of axially spaced peripheral grooves in the external surface of the pipe (62). 5. A gun as claimed in claim 2, including at least two interchangeable barrel assemblies (30,60), in one of which the means coupling the pipe to the barrel is such as to restrain axial movement of the pipe relative to the barrel, whilst permitting rotational movement of the barrel relative to the tubular housing, and wherein the barrel is provided with a handle (72) for the manual application od <RTI ID=9.57> rotational movement thereto whereby to Hdjust the degrec of coincidence between the aperture in the barrel und the pasture in the housing alld to control the passage of muterial from the hopper into the barrel for entrainment by air passed through the pipe, aid in the other of which the means couplilug the pipe to the barrel is such as to permit relative axial movenlellt. of the pipe relative to the barrel, and an aperture plate is located at the front end of the barrel, the nozzle of the pipe having a llormal positioil closing an aperture of the aperture plate, the trigger mechanism when coupled to the rear child of the air pipe being operative to move the latter axially so that the nozzle moves between its normal position and a position inward of the aperture, whereby material eilteriiig the barrel from the hopper may be entrained by air passed through the pipe. 6. A guil as claimed ill claim 2, wherein the means coupling the pipe to the barrel is such as to permit relative axial movement of the pipe relative to the barrel, and all aperture plate is located at the front end of the barrel, the nozzle of the pipe having a normal positioil closing all aperture of the aperture plate, the trigger mechanism when coupled to the rear end of the air pipe being operative tO move the latter axially so that the nozzle moves between its normal position and a position inward of the aperture, whereby material entering the barrel from the hopper may be entrained by air passed through the pipe.

Inventors: NONIS, ITALO
Applicants: NONIS, ITALO
Application year: 1985
Main classification: E04F21
IPC codes: B05B7, E04F21