US2401503A - Air spraying device - Google Patents

Description

June 4, 1946.

J. A. PAASCHE AIR SPRAYING DEVICE Filed April 22, 1943 x xmw WWW/4 w M 0 P #w J M 3 7 U M 3 a r a w 41 1% W M 5 4 W L I w 0 W M 6 W W m r fl w 5 m a H7 3 aw .3 a 4 T H h 3 Z y m E. 5%.

Patented June 4, 1946 UNITED STATES PATENT OFFICE r 2,401,503

AIR SPRAYING D'EvioE J ens A. Paasche, Chicago, 11]. Application April 22, 1943, Serial No. 484,039

The present invention is particularly concerned with improvements in valve'controlling mechanisms employed to govern the volume of liquid such as paint to be applied to a work surface in the form of a spray. It has heretofore been the practice in some instances, as shown in my earlier Patent No. 2,059,706, to control the delivery of liquid such as paint by a piston operated valve mechanism. Such mechanisms have certain functional deficiencies which the present invention seeks to overcome. For example, piston operated valve mechanisms are subject towear and consequent leakage. Also such devices require continuous lubrication. The present in- 've'ntion contemplates a spray device in which valve control may be obtained by mechanism which is not subject to the wear experienced by a piston and which need not be lubricated.

More specifically, the present invention con templates an improvement in the bellows of that type of spraying device in which a liquid control valve may be shifted in response to the expan sion of a pressure responsive means such as a bellows which is connected with the air line.

The foregoing and other objects and advantages will be more apparent from the "following detailed description when considered in conn'ec- X tion with the accompanying drawing, wherein- Fig. l is a central longitudinal sectional view of a spraying device which is representative 'of one embodiment of the present invention;

Fig. 2 is an end elevational view or the device,

said view being taken from the left ofFig. 1 substantially along the line 2-2 thereof;

Fig. 3 is a transverse sectional view taken substantially along the line 3-3 of Fig. 1;

Fig. 4 is a transverse sectional view taken substantially along the line 4-4 of Fig. 1'; and

Fig. 5 is a transverse sectional view takensubstantially along the line 5-5 of Fig. 1.

Referring now to the drawing more indetail 1" wherein like numerals have been employed to designate similar parts throughout the various figures, it will be seen that one embodiment of the present invention constitutes a spraying device which is designated gene-rally 'by the numeral In. This device Ill comprises a forward portion or nozzle assembly generally designated by the numeral I 2, a central body portion I 4 which carries the nozzle assembly l2 'and a rearwardly positioned bellows supporting structure designated generally by the numerallii. The f bellows supporting structure is includes a cylindrical casing or housing I 8 which is clo'sed at its rear or right extremity, Fig. 1. by a closure member 20. The opposite extremity of the housing I8 2 is reduced and internally threaded to receive a bearing member 22. This bearing member 22 has a conical outer bearing surface which is complementary to a conical bearing surface on the body l4, and these two :bearing surfaces are secured against each other through the agency of a coupling hut '24, Fig. 1. This nut 24 makes a threaded engagement with the periphery of the right extremity of the body l4 and is provided with a flange portion 24a which bears against a shoulder on the bearing member 22.

Liquid such as paint is introduced to the front extremity of the sprayer device l0 through a suitable conduit 26 which is coupledat 28 with a nipple 30 formed integral with and extending outwardly from the centralbody portion H. The fluid or liquid passes through a channel 32 and thence into a chamber or passage 34 withina nozzle tip 36 which forms 'a part of the nozzle assembly l2. The communication between this passage 34 and a restricted discharge orifice 38 is controlled by aneedle valve member 40. The degree to which the valve member 40 is open will determine the amount of paint discharged in a small stream through the discharge orifice 38. The valve member 40 forms a part of an elongated valve stem 42 which is coupled at its opposite or right extremity, Fig. 1, with a pressure responsive bellows mechanism designated generallyby the numeral 44, later to be described. It will be seen that the nozzle tip 36 makes threaded engagement with the left or outer extremity of the central body portion M and is provided with an outer tapered surface foruaccommoda'ting an air can or fanning head 46. v The stream of paint discharged from the orifice 38 is acted upon by fluid or air streams from discharge ports [8 and this causes the solid material stream issuing from the orifice 38 to be transformed into an atomized stream comprised of small particles of substantially uniform size delivered against the surface to be treated. For a more detailed description of the fanning efiect produced by such ports, reference is made to my Patent No. 2,l39,1 33, dated December 6, 1938.

For aclear understanding of the present invention it will suflice to say that fluidor air under pressure is introduced through a conduit '50 which is co upled with a nipple 52 formed integral with and extending radiallyof the housin I6.

pressure right extremity. of the v at the opposite extremity with the restricted disserves to initiate breaking up the material stream i and to carry the material toward the surface of E the body to be treated in the form of a head spray of substantially round pattern circumscribing.

only a relatively small area. .The air streams is-. suing from the ports 48 cooperate with'the air streams from the annular port 66 to produce the desired spreading or farming of the material directed to the work surface. y

The volume of air issuing from the ports 48 is controlledby a valve member 68.. This valve member 88 is mounted within a-nipple. or a housing It formed integral. withthe. central body portion M. The outerextremity of the valve mem ber 68 is connected with a knob I2 vwhichmaybe manually, rotated to control the space between the-valve member 68 and its complementary valve seat. 68 serves to prevent inadvertent adjustment thereof and also to retain andcompress packing A coiled spring M surrounding the valve material 15 in place.-. This prevents leakageof air along the stem of the valve member 68. A passage 16 establishes communication between the valve '68 and one'of the longitudinal passages Ell. When the valve 68 is open,jcommunication is establishedbetween. this passage 18 and the restricted discharge ports d3... ICAt this point it shouldbe understood that the farming head 46 isclamped againstthe left extremity of the central body portion Mthrough the agencyof a suitable clampijng ring 18 which is provided with knurlings or protuberances Sii'along its outer surface to facilitate manual adjustment thereof.

From the foregoing description it will be apparent that in order fOr material such as paint to be discharged through the orifice 38 the valve 40 must be open. This valve is normally closed when not in use. However, as soon as air under is ,introduced through the conduit andinto the central chamber expansion of a benow BZ'taKes piece; Theiright extremity, Fig. 1, offthisbellows 8 2 is connected tothe valve stem bya Couplingt. I v interposed between the coupling 84 and the. closure or cap 20. This coupling! includes a member 89 having a peripheral portion projecting beyond the bellows which is hexagonal and an inner portion 9 y and provides a support for the valve stem 42. The 'alve' stem 42 is threaded to receive a member 93' whichprovi'des a seat for the leftextremityoft the coiled pring 86 and A coiled spring 86 is whic'hprojectsf within the bellows which is, adapted to be slidhbly ,Iiested within a complementary recess provided in the member 89. Th provides a very simple structure 'to fafcilitate removal of the valve stem without disturbingthe bellows proper Thus when the bel lows '82 expands to the right, this exparisiontakes place against the coiled-spring'86. The extentto which the valve flll'will open will be'dependent upon the pressure exerted against the bellows 82.

A coiled spring 81 surrounding thejvalve stem 42 servesto retam'packing rings at oppositeextremities thereof position. The action of the spring 81 is such as to compress the packing pothe bellows 82 anditsassociated parts, instantaneous opening of the valve 48 is accomplished.

ment, eliminates the necessity of lubricating the positive action and parts to insure sensitive and also eliminates wear resulting from friction. The

pressure exerted by. the spring 86 and conse- .quently the responsiveness of the bellows 82 to variations in pressure may be controlled by a manually adjustable screw member 88.

This screw member 88 makes a threaded engagement with the cap 28. Rotation of the screw member in a clockwise direction, as viewed from the right, causes it to move inwardlyand. thus subject the coiled spring 86 to increased compression. In this manner the opening of the valve member 40 in responseto variousair pressures may be controlled. A suitable disc '90 is secured upon the cap 20 by. anut 92. This disc 90 may be suitably graduated to indicatev various pressure settings for the screw 88. A pointer member 94 carried by the screw 88 serves to designate the pressure setting as indicated upon the disc 90. I

From the foregoing it will be apparent that the present invention contemplates a sprayor airbrush device of improved practicalconstruction. The control of material or paint delivered to; the restricted dischargeorifice by the use of the pres sure responsive. bellows 'mechanism previously described represents a distinct advancement over prior devices with, which I am familiar. By employing the pressure responsive bellows arrange: ment positive opening of the valve is assured with improved sensitivity. The simplicity of the bellows control arrangement enables it to be economically produced, and the elimination of shiftable plung'ers, pistons or the like, requiring constant lubrication and encountering considerable wear, makes for efliciency in operation. Also the practical arrangement of th'evalve mechanism for controlling deliveryof air'under pressure to the fanning head represents a 'distinct. improvement over controls previouslyemployed. I

Obviously the invention is not limited to the specific structural. details disclosed herein but contemplates other modifications and changes without departin from the spirit and scope of theappendedclaims.

The invention is hereby claimed as follows:

1. Aspraying device, including in combination 'nozzlemeans for supplyingliquid to be sprayed to said nozzle, a valve for controlling the flow of said liduid means for supplying a gas under pressure tosaid nozzle, a Sylphon bellows, a bushing carried by said bellows, said valve having a stem slidably housed in said bushing, said stem having a {being positioned on said seat,a spring in contact with fsaid'head and biased to urgethe head to its seat in the bushing; and means providing combetween said gas supplying means and the interior of said Sylphon bellows. v

Q 2. A spraying deviceas in claim Lincluding in combinations; housing, said bellows being'positioned in' said housing, and meansfor removably securing said nozzle to saidhousing. f

A spraying device as in claim 1, including in combination means for adjusting the bias of said JENS A. PAAscrin" head, a seat formed on said bushing saicl head

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