US2054136A - Spray gun - Google Patents

Description

Patented Sept. 15, 1936 SPRAY GUN Harry Edward Pfaff, Lloyd Russell Shaffer, and

Alexander Metherell, Hamilton, Ontario, Canada, assignors to Tajmal Limited, Hamilton, Ontario, Canada, a corporation of Canada Application May 6, 1932, serial No. 609,658Y

3 Claims.

5 vide a spray-gun or paint-gun which is of a simple, compact and inexpensive construction lending itself to a simple, direct and easy control; which is highly efficient and thoroughly reliable in operation over long periods of constant use; which 'is Well adapted for spraying semi-viscous fluids without sticking or jamming, and for spraying uids containing abrasive materials all with high efficiency, minimum deterioration or wear, and long operational life. y l5 The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope' of the application of which will be indicated in the following claims.

In the accompanying drawing there is shown one of the possible embodiments of the mechan- Vical features of our invention in which,

Figure 1 is a perspective view of our spray-gun and'certain of its associated equipment in which the manner of support and control are indicated 'diagrammatically,

'Figure 2 is a vertical central sectional view on an enlarged scale of the spray-gun of Figure 1,

- Figure 3 is a vertical sectional View, on an enlarged scale, as seen along the line 3-3 of Figure 2, and

Figure 4 is a fragmentary vertical sectional view illustrating certain features of operation.

` Similar reference characters refer to similar parts throughout the several views in the drawing.

Referring now to the drawing and more particularly to Figure 1, there is shown a spray-gun or paint-gun I 0 which issupplied with a fluid to be sprayed from a tank I I by way of pet-cock I2 and flexible tube I3. Air under pressure, illus- Itratively eighty pounds per square inch, is supplied spray-gun I0 by way of flexible tube I4 and an air line not shown. 'Ihe spray-gun is' conveniently held in the hand, indicated at I5, in a position preferably at a lower level than fluid tank I I, nthe purpose of which will appear more fully hereinafter, where it may be accurately directed at -the lWork and quickly and precisely controlled in a manner more particularlyy described hereinafter.

Spray-gun I0 preferably includes a T-shaped -housing I6, conveniently formed of a light weight, strong and non-corrosive material such as alumi- 155 num. VThe upper portion II;a of the housing may be cylindrical in form (see also Figures 2 and 3) and is adapted to rigidly support certain operative parts of the device, as more particularly set forth below. The lower portion I6b of the T-shaped housing is conveniently fashioned as a hand-grip 15 member by which the spray-gun may be held and directed at the work as indicated above.

Suitably mounted within and extending from one end ofthe cylindrical portion I Iia of the housing is a cylindrical barrel I1 preferably formed of 10 a tough non-corrodible material such as brass which lends itself to accurate machining. One end Il'EL of the cylindrical barrel threadedly engages a collar member I3 which is supported within the casing and maintained in substantially co- 15 axial relation with the cylindrical barrel I1.

Collar I8 and the end I'Ia of the vcylindrical barrel Il are adapted to be snugly received within cylindrical housing IBa and maintained in rigid assembled relation therewith by set-screw I9, the 20 tip of which seats Within a circumferential grooved portion I8a of the collar; the rigidity of the assembled relation is enhanced by the circumferential-shoulder portion Ilb of the barrel which squarely abutsv the extreme end of the-cylindrical 25 portion I6'a of the housing. Y

To prevent unnecessary sharp projecting portions which might catch onto, for example, the garments of the operator or user, and further to reduce the thickness of the barrel wall and hence y3o its weight, the outer surface of barrel I'I is pref- -erablyl evenly Vtapered Yas atIIc commencing at a section flush with the outer surface of the cylindrical portion Ia of the housing .and continuing until a relatively thin walled section is reached. -35

This construction assures a continuous outer lsurface throughout the regions indicated, a firm and rigidV connection between barrel and the housing, and a minimum over-all size and weight of barrel. 40

. Further `assurance 'of thefreedcm from sharp projections is achieved by the use of llister-head screws throughout (similar to the above-mentioned set-screw I9), which are counter-sunk so that'ftheir heads are flush with the surface con- '45 Vtour of adjacent parts.

The thin wall end IId of the barrel is interiorly threaded and adapted to` engage a nozzle 20 (see also Figure 4) provided with an exteriorly threaded portion 20a, Va circumferential groo-ved portion 2il,'and a shoulder-abutment portion 20. NozzleZl isvcircumfere'ntially knurled as at-ZI)d (see Figure I1) providing a gripping surface by which the nozzle may be screwed into the barrel .-5-5

I'I or conveniently removed therefrom for purposes of cleansing and replacement.

A firm and tight fit between nozzle and barrel is assured'in spite of dirt, grime, etc., by means of the above-mentioned circumferential grooved portion 2Ilb of the nozzle which is contiguous with the shoulder-abutment portion 2l]c Vand adapted to receive any dirt or grime initially on the threaded portions or the abutting portions of either barrel' or nozzle.

Nozzle 2o is formed with a substantiauy ccnical recessed portion 2f]e terminating in a tapered hole portion or orice 20f through which the fluid is sprayed onto the work; the recessed portion and orice being preferably coaxial with barrel I 'I and cylindrical portion IIa of the housing.

To reduce excessive wear of the nozzle oriiice and contiguous surfaces of the conical recessed Y portion, the nozzle is preferably made of a hard Y zle 20, the fluid to be sprayed is 'conducted byY and durable material such as Monel metal which is relatively inexpensive, non-corrodible, and particularly well adapted to withstand the action of fine abrasives, such as finely ground quartz and sand which may be contained in the uid to be sprayed. Y d

Into the central space or chamber formed within barrel I'I and limited bycollar I8 andrnozthreaded portion 22h. of coupling element 22.

Coupling elementr22 is provided with a threadedV end portion 22c which'is received within a thick'wall threaded portion I 'Ie of the cylindrical barrel I'I, conveniently at a point along the lower side of the barrel in its contemplated position of useV (see Figure l)V and adjacent nozzle 20. The outer exposed portions of coupling element 22 and its associated sleeve 23 are preferably hexagonal inform (see Figure ,1) presenting opposite surfaces for a wrench or the like which may be used in assembling the spray-gun or dismantling it for cleaning purposes.

Spaced within the above-mentioned chamber I'I-I8-20 and substantially coaxial therewith,

` is a tubular' member 24, one end of which is invfrom which it is spaced a suitable distance; illus- Atratively a distance substantially equivalent to the diameter of orice 2|Jf. Tip member 25 is provided Vwithran axial hole portion 256,-V preferably ofma diameter appreciably less than that of -orice 20f, which Vis maintained in substantial alignment with the orifice. Y Y

Tubular member 24 with its associated tip Y member 25 are maintained in coaxial'relation with respect tobarrel I'I partially by means of collar I8, as will more fully appear hereinafter, and partially by a collar. portion 26a of an air-cock 26.

Collarvportion 26a of the air-cock is snugly received within the cylindrical portion I Ia of the ening of tubular member and air-cock being effectively prevented by lock nut 28 engaging theY threaded end portion 24b of the tubular member and firmly abutting an end collar portion 26a.

Air-cock 26 is provided with an outwardly extending bulbous portion 26e and a threaded end portion 26f both of which are provided with a central channel portion 26g interconnected with the interiorly threaded end portionV 26d. Bulbous portion 26e of the air-cock is'provided with a tapered hole portion conveniently tted with a taperedplug 29 having a single transverse hole portion 29a therein adapted to cooperate with and interconnect channel portion Zr` and interiorly threaded portion 26d of the aircock upon proper rotational positioning of plug 29.

The kupper end 29b of plug 29 ispreferably of an enlarged circular form, the outer periphery of which is conveniently knurled as at 29c (see Figures 1 and 3) to permit. a rm grip andrassure precise air control; the extent of the air control Ybeing conveniently gauged by the arrow scratched on the upper end of the plug 29.

Air-cock 26-29 is maintained in a tight andY serviceable condition by screw 30, threadedly receivedV within the lower end portion 29c of plug 29, and its associated washer 3 I, the upper rim of which rides upon the flat surface 26h associated with the bulbous portion 26e of the air-cock.

The extreme outer end portion of air-cock 26-29 is interiorly recessed as at 26 and adapted to seat a tapered end portion 32- of coupling member 32. Air-cock and coupling member are maintained in air-tight relation by a sleeve member 33 having Van inner rimv portion 33, which frictionally engages an outwardly extending rim portion 32lo of coupling element 32, and a threaded portion 33b threadedly engaging a threaded end portion 26f of the air-cock.l

The Youter surface of sleeve 33 may be hexagonal in form (see Figure l) thus presenting-opposite gripping surfaces for a wrench or a similar tool whereby, upon turning sleeve `33 further up onto the threaded end of the air-cock, a rigid and air-tight coupling is achieved.

Compressed air is supplied the spray-gun, as mentioned above, by way of ilexible hose connection I4, one end I4a of which is stretchedV over an enlarged'corrugatedV portion 32u` of air coupling member 32. A direct air passage is provided through air hose I4,` through coupling member 32, air-cock channels 26g, 29.EL (where plug 29 is in an open. position) 25d, tubular member 24, channel c of tipI member 25, and out through orifice 20f. As indicated above, Vthe air may be controlled at the spray-gun by merely rotating plug 29 into a completelyY closed on par- 4tially closed positionidepenkding upon the require Yments of the work to be done.

The air flows out through the orifice 20f at a relative high velocity carrying with it a portion of the iluid contained in chamber I'I-I8-20 supplied, as mentioned above, fromtank I I.4 The fluid from chamber l-'l-'J-fzliiiowsbetween the conical tip portion of tip member 25 and the conical recessed portion-20 of the 'nozzle (see Figure 4) Where it meets a column of air, coming from a relatively small central channel 25c of tip member 25, and moving at a relatively high veloc# ity; air and uid particles mixing in passing through orifice V2|f and forming a spray which. is directed at the work.

In order-that the spray may be effectively controlled, there is provided a second tubular member 34A which is slidably-mounted on tubular member 24 and is slidably received withinlthe axial hole portion fb'of collar I8. One end of tubular member 34 terminates in a frusto-conical. surface 34@L which is adapted to firmly contact conical recessed surface 2i)e of nozzle 20. The other end of tubular member 34 is exteriorly threaded as at 34b and adapted to receive a hub portion 35Il of Aa disk member 35 (see also Figure 3).

Slidably mounted tubular member 34 is normally urged into Contact relation with nozzle 2|) at their respective frusto-conical surfaces 34a and 20e, preferably by'a coil spring 36 axially mounted about tubular member 24. One end of spring 36 is slightly expanded to be received withina grooved portion 35b ofV disk member 35 and the other end of the spring squarely abuts lock nut 28. Y

Thus, it will be seen that spring' 36v normally presses surface 34a of member 34 into firm contact with-surface 20e of nozzle 20 and thereby cuts off communication between chamber I'l-8-20 and orifice 2Ilf. When in this position the column of air flows at high velocity through member 24 and orifice' 20f without drawing any of the uid from chamber II-f8-2'0. If now, the surface 34a is retracted from the surface 20e (in the manner hereinafter explained)l the fluid in the chamber 1|820 flows or is drawn into the path of the escaping air and is sprayed thereby out through the orifice 201'.

This construction is particularly adapted to withstand wear under the action-of fluids containing abrasive materials since the flow of iiuid at high velocity is largely limited'to the' especially durable nozzle orifice and since the ow at low velocities past the partitioning or cut-off section is substantially uniform through 360 about the axis of the chamber and nozzle thus causing a uniform wear. A tight closure at the partitioning section or at the section of fluid cut-off is assured, in spite of wear by the vaction of spring 36 on the tubular partitioning member 34.

To prevent the leakage of fluid'into the sliding joint between the slidably mounted tubular member 34 and collar I8, and thus to prevent excessive wear and/or sticking and jamming of the vslidable member; a flexible jacket3l, preferably rubber, is stretched onto the tubular member 34 adjacent a circumferential rim portion 34c thereof and onto an extended neck portion I8c of the collar I8. A tight connection between the tubular member and neck portion of the collar may be assured by cementing the rubber onto these portions in any suitable manner.

In order that the rubber jacket 31 may permit relative motion between tubular member 34 and collar I8 without jamming or without necessitat- `Ing an excessive force, the jacket is preferably initially expanded as at 3iva by a flange I8d formed 'on neck portion ISC' of the collar.

tially (sufficient clearance being allowed between jacket 31 and barrel l1 to prevent obstruction of .the sleeve in expanding) and soA preserves a tight joint between tubular member 34 and colilar '|8.

Retraction of the slidable tubular member 34 against the action of spring 36 is preferably ei'- fected by a lever 38, conveniently constructed of a strong, durable and non-corrodible metal such as brass, in the form of an irregularv at portion 38aY and a broadA half-round edge portion 38h.. The iiat portion 3.8av of the lever is snugly received lwithin a` deep slotted portion H5U of the spray-gun. housing HiY (see alsoFigure 3) where it is constrained from loose side-play although freely permitted to move back and forth within the slot. Lever 38 is provided with an upper hole lportion 38c which is adaptedl to receive-a screw 39, the threaded end of which engages a threaded portion of the hand-grip portion. IE5b of the spray-gun housing; .screw 39 thus serving as a pivotal mount for the lever. To prevent excessive movement of lever 38, a flat portion 38e thereof is deepened as at 38d and provided with a slotted portion 3Be laid outy along an arc Ydescribed from the pivotal screw 39. Slotted 'portion 38e is preferably of such dimensions as to Vsnugly receive a stop 40 conveniently in the form of a screw threaded into a suitable threaded hole provided therefor-in the hand-grip portion of housing |.6 (see also Figure 1)r With lever 38 so mounted in the hand-grip part 161 of the spray-gun housing, the halfround flat portion 38b is positionedalong the front edge of the handle Vor grip and is adapted to receive the direct pressure from the fingers of the hand (see Figure 1) as thisportion. ofthe spray-gun is'tight'ly squeeezd or gripped.

It may at this point be noted that the lever 38, and especially its half-round outer portiomiis of sufficient length to accommodate the finger width of the hand so that a highly efficient gripping action (and hence control as willi appear more fully hereinafter) is achieved.. The width of the half-round outer portion 38h'of the handi lever is preferably somewhat in excessv .of-the adjacent front edge of the hand-grip portion of the spray-gun housing so as to effectively prevent squeezing or pinching of the fingers between lever and hand-grip.

Actionof lever 33 on the slidableV tubular member 34 is preferably achieved through a mechani- -cal element 4l provided with a hole portion 4Ia adapted to snugly receive a pivotal mounting screw 42 (see also Figures l and 3') suitably secured in the hand-grip'portion of the spray-gun housing. Mechanical element 4I is conveniently of brass and of such a thickness as to be snugly received within the slotted portion I 6G of the spray-gun housing (see Figure 3)., and is preferably provided with a toe portion 4lb which directly contacts ari-'outwardly extending flange or ri m portion 35y of the disk member 35 (see also Figure 3) which, as above-mentioned, threadedly ,l

engages the tubular member 34. Element 4l is provided with a heel portion 4I@ which contacts an extended toe or lingerl portion V38f of lever 38 whereby motion of lever 38 is transmitted by way of mechanical element Y4| and disk 35 to the tubular member 34.

In-order that maximum efciency of the lin'kagebetween lever and retractable tubular'member may be realized, the point of contact SSL-MC is in substantial alignment with pivotal supports 35i `(see. Figure 3i) and? 42, andfsimlarly contact Ywhichwear'between lever and tubularmember is substantially reduced.

As mentioned above, the extreme end of tubular member 34 is urged into a irm contact with the recessed Wall portion of nozzle 20 under the portions 38b and` 38f).

action of the relatively stiff spring 36 (necessitating a lever of commensuratelyhigh mechanical advantage in order to actuate the tubular memberagainst the spring action; the mechanical advantage here being the relative lengths of To provide a firm contactVV under the action ofV spring 36, a slight amount of play is allowed between the lever 38, mechanical element 4l and disk 35 associated with the tubular member 34. This play is provided through the slotted portion 38e of the handgrip lever; and may be controlled by the length of slot provided.

In using the spray-gun, the slight amount of play provided is immediately takenrup byk that lightV pressure'of the handY which is Vjust necessary tohold the spray-gun firmly. v

As the grip of the hand on the butt or handgrip portion of the spray-gunV housing is tightened, lever 38 is rotated in a counter-clockwise direction as seen in Figure 2, about the pivotal support 39. Throughout this motion toe or finger portion 38f of the levervacts on heel 41 of the mechanical element 4I causing a clockwise rotation of the latter about pivotal support 42, resulting in a retraction of slidable tubular member 34 (against the action of spring 36) under the V action of toe 4Ib of the mechanical element or Y diskr35 associated therewith.

*Further retraction of the tubular member 1 under a-continued increased gripof the butt of VF45 the spray-gunV is Vprevented by theV end portion of lever slot 38e comingY up against the stop 40. This, however, does Vnot occur (see Figure 4) until the end of tubular member Y3l! is clear of the slant-walled or conical tip portion'of the tip member 25 associated with the inner tubular member 24 thus removing the partition between fluid chamber `I1|87-207 and orifice 20f and allowing free passage of the fluid material from the chamber out through the orifice.

By changing the amount of pressure applied by the hand in gripping the spray-gun the extent of the retraction of slidable member 34, and hence the size ofthe passage between chamber and nozzle orice may be effectively regulated. This gives an effective control of the amount of fluid sprayed and the proportion of Yfluid to air thus permitting a change in the characteristics ofk Vthe spray dependent upon the nature of the work being done. Y 1

A relaxation Vof the hand permits a reestablishment ofjthe partition between iiuid chamber I'l-I8-20 and orifice '20f and effectively cuts off the iiowY ofthe spray iiuid. Thereis, however, a

Ymaintenance of the Ydirect passage ofair out through the nozzle orice 20f which may be directed against the wet sprayed Work surface to produce a rough or stipple effect pleasing to the eye;`the direct air iiow serves to maintain tip 25 and nozzle 20 in a cleanconditionassuring high operating efficiency and effectively preventing sticking, jamming ornotherr operational delays. Y Y

- v ItVV may atY this point be noted that as a result t of the maintenance of the direct flow of air out' through the nozzle there is substantially no back pressure against either the spray-,gun Yor the air line Vupon 'cutting off the spray liquid. 'I'hus the various parts of the gun are subjected to pressures Y substantially constant throughout operation which precludes Vsudden stresses on the various parts, lessens wear and generally makespfor a smoother operationpof the'gurn'andY its auxiliary equipment. Y Y Y In using theV spray-gun, the fluid-containing tank Il is preferably positioned at a level slightly above that of the barrel portion l1 of the gun (see Figure 1) so that thecfluid to be sprayed will feed by gravity into the chamber I'l-l8-20 of the spray-gun where its iiow about the tip lof the the spray-gun because of an over-sized particle V3C lodging in orifice 20f, or for example iron rust lodgingY in channel 25c of tip member 25, an auxiliary nozzle and tip member are conveniently carried within the lower part of the hand-grip portion of the spray-gun. Thisportion is threaded as at I6d to receive ran auxiliary nozzle |20 and is recessed as at I6e to accommodate a portion of the unthreaded tip end part of thenozzle to prevent undue projection of the'same above the outer surface of the gun butt.

Conveniently supported Within the yinteriorly threaded butt portionof the spray-gun, and resting on auxiliary nozzle |20, is theauxiliary tip member |25. siderable practical advantage in that an extra nozzle or tip member may be accessible to the operator or Workman 4thus permitting execution of the work with minimum delay in spite of the many possible causes for delay. Y

It kwill thus be seen that there hasV been provided in this invention a device in which the various objects hereinbefore noted together with many thoroughly practical` advantages are successfully achieved.v Y v ,Y

, As many possible embodiments may be made of the above invention, and as many Vchanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense. Y Y

We` claim:

1. In a device of the combination, a body portion havingY a chamber including oppositely positioned open end wall portions, a tubular member extending into said ber, a second tubular member slidably mountedl on said first-mentioned tubular member extending into said chamber through said first-mentioned open end wall portion thereof, means for I moving said slidably mounted tubular member This construction is of con-V character described, in Y into contact engagement with said second open end wall portion of said chamber and retracting it therefrom, and flexible Walled means for effectually sealing said chamber at the point of entrance thereinto of said slidably mounted tubular member.

2. A spray-gun comprising, in combination, a body portion having a chamber for paint and the like, with an outlet through which the paint is to be expelled; a tubular compressed air conduit within said chamber, having a nozzle near said outlet but spaced therefrom and in predetermined relation thereto, leaving a pocket of constant dimensions between said nozzle and outlet; a valve member encircling said tubular conduit near its nozzle, and arranged to supply a. partition between the paint chamber and said pocket, to shut off and regulate the flow of paint to said pocket and outlet; means supplying a seat for said valve member, said seat encircling the nozzle and spaced from said outlet, the outer extremity of the nozzle being positioned between the valve seat and the outlet; manually operable means for seating, unseating and regulating said valve member; and means for controlling the flow of compressed air through the nozzle, pocket and outlet, independently of the operation of said valve member.

3. A spray-gun comprising, inoombination, a body portion having a chamber for paint and the like, with an outlet through which the paint is to be expelled; a tubular compressed air conduitv within said chamber, having a nozzle near said outlet but spaced therefrom and in predetermined relation thereto, leaving a pocket of constant dimensions between said nozzle and outlet;

a valve member consisting of a sleeve encirclingk said tubular conduit near its nozzle, and arranged to supply a partition between the paint chamber and said pocket, to shut off and regulate the flow of paint to said pocket; means supplying a seat for said valve member, said seat encircling the nozzle and spaced from said outlet; and manually operable means for seating, unseatng and regulating said valve member.

HARRY EDWARD PFAFF.

LLOYD RUSSELL SHAFFER.

ALEXANDER METHERELL.

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