US2747931A - Gun shroud - Google Patents

Description

May 29, 1956 R. w. WILSON 2,747,931

GUN SHROUD Filed May 27, 1952 2 Sheets-Sheet 1 INVENTOR BY K LI Loczs k RNEY May 29, 1956 v R. w. WILSON GUN SHROUD 2 Sheets-Sheet 2 Filed May 27, 1952 ?II III INVENTOR WMU/KO/ZZtm M,

BY Kan. F1404:

ATTORNEY United States Patent 6 F GUN SHROUD Rufus W: Wilson, Huntingdon, Pa., assignor to Wald Industries Inc., Huntingdon, Pa., a corporation of Pennsylvania Application May 27, 1952, Serial No. 290,276

3 Claims. (Cl. 299-285) The present invention relates to an attachment for spraying apparatus. More particularly, the present invention relates to a shroud for attachment to a road marking spray gun.

Prior to the instant invention, various devices have been utilized with spraying apparatus for defining trafiic lines on roads or pavements. However, these heretofore known devices have generally been undesirable since they do not sharply define the traflic marker and, furthermore, are subject to constant cleaning and repairs. One of these heretofore known marking assemblies consists of a pair of revolving discs which are adjustably mounted with a paint spray gun positioned therebetween. The discs are adapted to direct the spraying material ejected from the spray gun in a pattern on the road in predetermined widths. These disc devices were found to be generally undesirable since paint mist had a tendency to form on the inside surfaces thereof with the result being that in those cases where lines were to be skipped, such as at street or road intersections, the accumulation of mist on the discs dripped off onto the road. It was also found that if the spray gun was shut oif, and the discs were moved along the road surface, the accumulated mist deposited thin parallel lines on the road which were not only unsightly but were confusing to the pedestrian and driver. Furthermore, actual practice has proved the discs to be cumbersome inasmuch as they require bulky supporting structure which necessitates complicated mechanical disc retracting mechanism. Moreover, constant maintenance is required to keep the discs clean and, due to the constant contact of the disc peripheries with the road surface, frequent disc replacement is necessary.

. Devices similar to the rotatable discs have been used to direct the spray pattern on the road and include such devices as sleds, which are adapted to be positioned on either side of the spray gun. The use of the sleds has also been found to be objectionable for similar reasons discussed above, that is, mist from the spray gun collects on the inner surfaces of the sleds and drips off onto the road when the sleds are lifted therefrom.

Air current ejectors have been used with the most success with spray guns, but even these devices have been found unsatisfactory. The air ejectors operate to direct the spray pattern on the road by ejecting air from nozzles located on either side of the spray gun. However, this operation requires elaborate piping arrangement as Well as various adjusting and locking means, which features make the device too complicated for ordinary use.

Still another means in use heretofore with a spray gun for defining a road marking pattern is a device which incorporates wing-like pieces of light sheet metal suspended on wires on either side of the spray nozzle. In this type of device, adjustment of the wing-like pieces has been more or less haphazard and, due to the lack of suflicient enclosures in protecting the spray itself, prevailing winds and air currents generated by passing traffic, have caused undue disturbances in the spray, thereby distorting the line pattern laid on the road.

2,747,931 Patented May 29, 1956 It is an object of the present invention to provide a spraying device which will concentrate the spraying material in even distribution on the road or pavement.

Another object of the present invention is to provide a shroud that is adapted to be secured to a conventional type road marking spray gun and that will direct the spraying material therefrom to the road or pavement in even distribution thereon.

Still another object of the present invention is to provide a paint spray gun shroud that is adapted to prevent paint mist from accumulating on the inner surfaces thereof, thereby preventing unsightly blotches on the street or pavement during the road marking opera-' tion.

Still another object of the present invention is to provide a shroud having passages therethrough for admitting air which will act to prevent accumulation of mist along the inner surfaces of the shroud.

Other objects and the nature and advantages of the instant invention will be apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. 1 illustrates one form of the present invention wherein the shroud is shown in vertical section secured to a road marking spray gun;

Fig. 2 is an elevational view of the shroud illustrated in Fig. 1;

Fig. 3 is a plan view of the shroud illustrated in Fig. 2;

Fig. 4 is another form of the present invention illustrating in vertical section a modified shroud secured to a road marking spray gun;

Fig. 5 is a plan view of the shroud shown in Fig. 4; and

Fig. 6 is an elevational view of the shroud shown in Fig. 5.

Referring to the drawings, and particularly Fig. 1, one form of the present invention is illustrated secured to a road marking spray gun, which is generally indicated at 10. The road marking spray gun 10 includes an air chamber 12 which houses an air operated needle valve (not shown). An inlet port 14 is connected to air chamber 12 and directs air under pressure to a diaphragm located in the air chamber for operating the needle valve in the conventional manner. Below the air chamber 12 and integrally connected thereto is a barrel 16 which has a paint inlet port 18 and an air inlet port 20 formed therein. The spraying material or paint is introduced into the spray gun through the port 18 and passes through the needle valve (not shown) into the lower portion of the barrel 16 where it is atomized and ejected through a nozzle 22 suitably mounted on the lower portion of the barrel 16. The nozzle 22 is arranged to discharge a fan-shaped spray which is indicated at 24. The nozzle 22 is disposed generally perpendicular to the road indicated at 26 over which the spray gun is carried by suitable apparatus. The fan-shaped pattern 24 is shown forming a stripe S on the road 26.

The barrel 16 is adapted to have secured thereto a shroud assembly which includes an internally threaded nut element 28. Formed around a lower portion of the barrel 16 are the threads 30 which receive the nut element 28 in threaded relation.

Referring to Fig. 3, the nut element 28 is shown having formed thereon a series of projections 32 which define therebetween open spaces 34. Referring again to Fig. 1, the shroud assembly is shown including a shroud body 40 which is secured to the nut element 28 in pressedfit relation. The shroud body 40 is a machined cylindrical tube of steel, bronze, plastic or other suitable material and is formed with a thin wall section and a polished inside surface. The top of the shroud body is machined to provide a pressed fit on the projections 32 and the bottom is cut away to form oppositely disposed concave sides 42, 44 and oppositely disposed curved lip sections 46, 48. In position,-=the upper portion of the shroud body; 40 closes the outer sides of open spaces 64. The-open spaces 34: thereby define-passages whichare spaced around-the topof the shroud-and which project into-the interior thereof as illustrated in Fig. 1.

In operation, the spray gun shroud body 40 is secured to-the-spray'gun as shownain Fig. 1, andthe assembly is-suitably positioned on a road spraying apparatus vehicle. The paint is admitted tOthe barrel 16 and is controllably dischargedfromthe-nozzle 22: onto the road surface 26 in:the fan-shaped spraypattern 24. The dischargeend orlip sections'46; 4-8-of the shroud body 40 successfully'confine-the spray pattern to a definitely predetermined width, thereby enabling a clearly defined'line to be sprayed on the road surface by the spray gun apparatus. Moreover, the-pattern isunaffected-by external air currents, since the lip: sections 46, 48 act as a baffie protecting'the spray'pattern'from air disturbances caused by high-speed passing traffic. -It is understood that the width of the spray pattern S-may be varied byverticallyadjusting the'positionof the spray gun 10 along.

with the'attached shroud body 40; If a more narrow spray pattern is desired, the spray gun ismoved closer to the. road 26, while a wider spray pattern may be eifected by lifting the spray gun'to 'ahigher position with respect to the road 26. However,'-the shroud body 40 must always be maintained at a" suitable distance from the surface of the road 26, thereby effecting a definite spray pattern under all conditions.

As the paint is discharged from the nozzle 22 onto the'road surface 26, a fine misticollects 'along. the inner surfaces of the shroud body 40. This mist, if allowed to'remain on theinner'surfacesofthe shroud body 40, would subsequently drip off into the road during the spraying operation :and causeiunsightlyiblotches thereon. Moreover, when the spraying operation is stopped'm'omentarily, such asat 'streetintersections, or shut down, the collected spray would drip off the shroud, thereby marring the appearance of th'e'finishedmarked line. The cut-away sides 42, 44 are. limited in surface area and thereby prevent'thei'paint mist emanating from the nozzle22 from collectingithereon. However, the curved lip sections, 48, which defin'eithe'width of the spray pattern, are continuously subjected to the'paint mist and would ordinarily'collect a prohibitive amount of mist which would. result 4 inthe :oibjectionable bl'otching. The spaces 34, whichare formed in' the nutelernent 28, provide convenientlopenings for thefadmission of air from the surrounding atmosphere. The inc'oming'air forms an aircurtain which'moves downwardly along the'inn'er surfaces-inf the'shroud'body 40,- as shoWn by the arrows inFi'g; 1. It is apparent thatltheiair curtain, as it moves downwardly alongth'efshroud bodyinner surfaces, carries'the mist circulating therearound back into the spray pattern, thereby eliminating'the possibility of mist collection and. subsequenti'dripping :onto the road;

Referringnow to Fig....4, azmodified form of shroud assembly is illustrated,.secured to the spray gun described hereinabove. The modified shroud assembly comprises an upper'nut 5t 'havinginternalthreads which are adaptedtob'e'threadedly'engaged by the threads 30 locatedon theilowerportionof the 'spray gun barrel 1'6. Disposed around the upper nut Sila'n'dprojecting'therethrough are a plurality of passages 52, whichareprovided for directing atmosph'eric air to the inner surfaces of shroud body 54. The uppernutStl is formed witha knurled surface 56 'which provides*agripping surface for engaging the nut 56) on the 'threadsfi'tl. Also formed on the nut Share threads '58 whichengage aknurled lower. nut '60. The lowernut60isformed with aflange 62 at the lower "end thereof I which interlocks with a flange 64"integrally formed onthe upper end of the shroud body 54. The flange 64 is securely held in place by the nut '60" against thelower end of'nut 5i), which forms with the shroud body 54 the inner surface of the shroud. The shroud body 54 is cut out at the lower end thereof to form the oppositely disposed concave sections 64, 66 which face in the direction of travel of the spray gun 10. Oppositely disposed curved lower lip sections 68, 70, which limit a spr-ay'pattern, indicated at 722, face in a direction at right angle to the direction of travel of the spray gun It) and -areadapted-to-preventair currents from disturbing the spray pattern 72 as'it is discharged from the nozzle 22 onto road surface 74. As shown'in Fig. 4, the spray pattern 72nforms the stripe S on .the road surface 74.

In operation, thepa'int spray gun Iii is moved along the road surface 74, discharging the spray pattern 72 from the nozzle 22 in a predetermined width determined by. the nozzle 22land lower lip sections 68, 79. Paint mist emanating fromthe nozzle 22 and circulating along the-inner surfaces-of the shroud body 54 isforced back into the spray pattern by an air curtain drawn through passages52 form'edin the upper nut St). It is apparent from the foregoing that thepaint mist is successfully prevented from accumulationalong the:shroud body walls, thereby eliminating any possibility of subsequent drip onto theroad surface. It is furthermore apparent that the shroud lower lip sections 68, 70 not only definea definite. spray pattern, but prevent any outside air currents from disturbing the pattern as it is dischargedifrom the-spray gun nozzle onto the surface of a road or pavement;

It will be obvious to those skilled in-the art that various changes -may-be'made without-departing from the spiritof the-invention and, therefore, the invention is not limited to what is shown .in thedraWings and described inthe specification, but only as indicated in the appended claims.

What-:is claimed is:

1. In an atttachment for a road marking spray 'gun from whicha' spray pattern is discharged, an upper nut threadedly engaging said spray gun, alower nut threadedly engaging said-upper nut, a' cylindrical'shroud body interlockedbetween said upper nutand said lower-'nutiin concentric relationtherewithand surrounding the spray gun nozzle, tsaidau'pper nut-having a'plurality ofpassages formed therein.extending'intothe interior of said shroud body, said passages adapted'to admitair'from the surrounding atmosphere into the. interior of said. shroud body for preventing'the collection of paint mist along the inner surfaces thereof, said shroud body being .cut out at the :lower portion thereof to' define oppositely. disposed concave sections and oppositely disposed'curved. lowerlip-sections, said lower lip sect-ions adapted'to'define the width of the spray pattern and to prevent air currentsfrom disturbing said spray pattern.

2. In an: attachment for a road marking spray gun from which a spray pattern is discharged, means engaging said spray gun, means engaging said first-named means, a-hollowcylindrical member interlockingly seforming an air curt-aintherein, said air curtain adapted.

to -move downwardly along the inner surfaces of said .member and to carry mist emanating from saidspray gun baclcintos-aid spraypattern.

3..Inwan2attachment for a road markingspray gun, means threadedlyengaging said spray gun, means threadedly engaging said first-named means, a hollow member. securedbetween saidaforesaid means'in concentric relation therewith and adapted to be positioned in spaced relation with respect to the road to be marked, said firstnamed means having passages formed therein extending into the interior of said hollow member, said passages adapted to transfer air from the atmosphere into the interior of said hollow member for preventing paint mist 5 from accumulating therein.

1,720,273 Henry July 9, 1929 6 Thompson Dec. 31, 1929 Steinke Mar. 31, 1936 Lewis June 4, 1946 Fisher July 18, 1950 Sohmer Aug. 15, 1950 Tallman June 5, 1951 Mosher Aug. 4, 1953

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