US2533953A - Spray gun - Google Patents

Description

Dec. 12, 1950 D. J. PEEPS 2,533,953

SPRAY GUN Filed Sept. 8, 1947 3 Sheets-Sheet 1 INVENTOR DONALD J. PEEE'S QQPCLM ATTORN EY Dec. 12, 1950 J, Ps 2,533,953

SPRAY GUN Filed Sept. 8, 1947 3 Sheets-Sheet 2 g wa l/7y.

48 WW 49 {I I 46 32 INVENTOR DONALD J. PEEPS ATTORNEY Dec. 12,1950 D, PEEPS 2,533,953

SPRAY GUN Filed Sept. 8,1947 5 Sheets-Sheet s INVENTOR DONALD J. PEEPs ATTO R N EY Patented Dec. 12, 1950 SPRAY GUN Donald J. Peeps, Toledo, Ohio, assignor to The De Vilbiss Company, Toledo, Ohio, a corporation of Ohio Application September 8, 1947, Serial No. 772,780

3 Claims.

This invention relates to an automatic spray gun using air for the atomizing medium and for opening the needle valve controlling the discharge of spray material.

A primary object of the invention is the provision of a spray gun of a compact and sturdy design.

Another object of the invention is the provision of reliable guide and bearing means for the air piston.

Still another object is the provision of a substantial stopping member to check the rearward movement of the piston.

An additional object is the provision of an easily disengaged joint between the spray material valve and piston.

Other objects and purposes of the invention will become apparent upon a reading of the following specification considered with the accompanying drawing in which:

Figure I is a side elevational view of a spray gun embodying my invention;

Figure 2 is a front elevational view of the spray Figure 3 is a rear elevational view thereof;

Figure 4 is a vertical section of the spray head detached from the main body member of the Figure 5 is a vertical section of the body member without the spray head; in order to show the air inlet 6 and the communicating passage M the lower rearward portion of this section is along a plane inclined laterally to the left of Figure 3.

Figure 6 is a vertical section of the connector assembly for holding the spray head and body together. This includes the air valve for adjusting the air fiow to horn ports on the spray head air cap; I

Figure 7 is a fragmentary vertical section of a rear portion of the spray gun taken on the line 1-1 of Figure 3 through the atomizing air supply inlet and air valve housing;

Figure 8 is a side elevational view of a portion of the rear end of the spray gun showing in vertical section the locking mechanism for holding the adjustable cylinder cap in selected position; and

Figure 9 is a fragmentary vertical section of the connecting portions of the spray material needle valve and the air piston.

The spray gun shown in the drawing consists of a main body portion I and a spray head 2 held together by a hollow connecting screw 3. l The body I has an air cylinder 4 closed by cap 5 at its rear end. Below the cap 5 are air inlets an air piston assembly 23.

2 6 and 1 for supplying air respectively to the air cylinder and to the spray head. Through a boss 8 on the body is a threaded bore 9 for receiv ing a mounting rod (not shown) for supporting the spray gun in any desired location.

From the forward end of the air cylinder I extend two vertically flattened arms I and II.; Near their rear ends these arms are joined by a narrow transverse section I2 in which there are upper and lower bores I3 and I4. The rear end of the spray head 2 is held between the forward ends of the arms In and II with the rear end wall of air inlet I abutted against the for: ward end wall of the upper bore l3. The inlet I5 is internally threaded at I6. The connector 3 holds the spray head on the body I by being inserted through the bore I3 and engaging the threads I6. The connector 3 (Fig. 6) has a ta-- pered shoulder H which seats around the rear end wall of the bore I3.

On the lower side of the spray head 2 is a spray material inlet connection I8. On the for ward end of the spray head is an air atomizing ca I9. Through the lower bore I4 in the web. section I2 extends the rear end of the spray material needle valve as well as the packing nut 2I and the packing retaining nipple 22, within which the nut 2I is threaded.

Within the cylinder 4 as shown in Figure 5 is This consists of "a supporting cup 24 around the periphery of which is held the piston leather 25 by means of disc 26.

An axially positioned rod 21 is inserted from the rear through a central bore 28 in the disc 26 until q a shoulder 29 on the rod abuts against the disc.

The forward end of the rod 21 is threaded through a central bore in the cup 24 and beyond the cup has a threaded connection with trigger 33 which opens the spray material valve 26 and atomizing air valve 39.

As shown in Figures 5 and 9, this hollow trig- 1 ger member 30 has a lateral opening 3| near its forward end for receiving the head 32 on the rear end of the needle 20. The opening 3| has an elongated portion 33 extending to the center.

of the forward end of the trigger for accommo-: dating the shank of the needle 20 adjacent to the head 32. To impel the needle forwardly tot its seat in the spray head a spring 34 is locat ed within the hollow portion of the trigger.

This spring has its rear end thrust thereagai'nstthe forward end of the rod 21 and its forward,- thrust against the needle through an intermedi-l The bore of the trigger. has a rearwardly facing shoulder 36 (Fig, 9)

ate movable disc 35,

' Whfill. the is .6

just behind the lateral hole 3|. This shoulder reduces the bore slightly below the diameter of the disc 35 whereby the disc may not move for ward beyond the shoulder. This keeps it from movin into the space ordinarily occupied by the I needle head 32' and interfering with'the'reinsermounted upon a rod having threaded engage-- ment with bore 9. Air hoses are fastened to inlet nipples 6 and 1 and a spray material. suplg y' hose connected to inlet I 8. The flow of air entering'nipple 6 is ordinarily controlled by a valve (not shown) in synchronism with theconv yor (also not illustrated) carrying articles to bespray coated. When an article is in position tobe coated the air enters nipple 6, travels through passage. into air cylinder 4' at the forward side of the piston- 23 and the piston under the force or the airpressure upon the piston leather 25 moves rearwardly;

After the initial movement of the piston the air also-acts upon the forward faceof the cup u. The piston moves rearwardly against the tension Off spring; 43 until the end of the rod 21 strikes against the inner side of cylindercap 5. shown in Figure 5 the cap is turned to its mostforwa-rdly position in which it does not permit the piston any movement. In practice the; capis set to stop the piston at a point where it will open the material needle to which it is attached at its forward end to a degreesuitabl'e tor the; desired" dischargeof coating material.

While the can Provides an adjustable stop means in its rearward position has threaded engagement with the cylinder is, sli ht and to relieve it of then receiving the blows ofthe; piston rod 21 the supporting member 42- for the spring 4.3; which member is. firmly threaded within the erlinder, has. a heavycentrally located sleeve portion? which not only acts as a. bearing guide 311 he. roibut also servesasa stop. for the piston of the piston assembly strikes its forward side. Y cylinde cap Sines. curn h 6. ;snac quid stantly around its f rward dge 1 A shown inEisure 8' a. sl ding pin. H5, is o a in abate 2., below thecrli der, 4- lhis pin. d. nward: h e ge. It: by a spring. 13 and: y zgsing notch. 69; ho ds. he. can ina yu rter turn positi n selected. o prevent the. p n. rom slipping, f om? t e. bo e. 12. a lock ng, screw. 1 entends int he. bore.- bl ks the. escapee; the sin by ntercepting a shoulder 15 on. he innenendoi thepin.

In the forward end of the: crlinder. is. apaclg- 7 ns... 11111 5. theinner. bor oi which so. g id s piston. by receiving the cylindricaltrigger 30' which time e-foliward xt s on. i; he..- piston. assembly Thro gh its onnection with the. needl 20 the rearward. piston movement. draws. the. needle. from. it seat. 46, in the. material. discha ge. p 41 allowing. the material rcaching the. tip. f m

he... connection. 1,8. to be. discharged iromthe. out-- let port. 48; of the tip... This. material. is ato aed.andshapedv nto. an. appropriate ran. pattern nid c arged rou d: itIfrQm the annular pening. 49' betw en. he. tip, and; the. air can l9; and; fr m p rts. 50 and the. air can. h aor a 5i! a 51' a e. ac u l y cir mie lr spacedas shown in Figure 2, although positioned in line in Figure 4 to illustrate their source of air. The air reaches the spray head from connection 1 past valve 39 which is opened against spring 52 by rearward movement of the downwardly extending finger 3! of the needle. This air travels through the passage 53 which leads through the arm H and terminates at opening 54 in the; bore l-3. From here the air passes through ports 55 in the connector 3 and enters passage 56 in the spray head. Here it is divided, one portion passing past the adjusted opening 5! between the valve 58 and its seat 59, then into passage 60, around baffies 6!, through annularchamber 62 and into passages 63 leading to the ports 50 of the horns 64 of the cap I9. The other portion of the air goes through the. port 65 (indicated with dotted lines in Fig. 4) into the annular chamber 56, and into the space 61 between the tip and the air cap, from which it flows through annular port 49 and air can ports 54;. As; in icated.. he= pre re of; th air to; the horns-is; determined by the; position of? valve; 5. as adiustedjbr u ing the knob. 63-

It may be seen from the above that thepi ton particularly well. supported and aligned by having the cylindrical portion oi the. trigger 3.0 extending forwardly from the piston assembly; and riding in they bore of nut 45. addition to having; the. rear extension of; red. 27; hearing m the sleeve 44 of the spring retainer 4%. The latter member is sturdily; constructed with asubstantial threaded en agement, with. the; cylinder and thereby provides a reliable; finalstop-fior-the piston. V When it, is desired. to. remove. the. spravhead with the needle, from the body it. is. readily accomplished releasing the connector 3. and after, the spray, head, is. partially detached, by moving the needle head, laterally through the port 3| in the side of the. needlebore. Replace ment of the trigger into. its connection withthe trigger 30 is done without difficulty: as the. disc 3.5 s. prevented. from; obstructing the spa e y the restriction of shoulder 33. Another feature. of the. invention. is, the arrangement. of the; pin l tor holding the. cylinder cap. in an desired position. This. purpose is. acccmplished. with. a. minimum number of parts located in a concealed. positiorn g If he sp ing 43 .weresupmrted unonthe can 5,. its tension against. he. pis onwQuld. vars c cording. t the: adjusted; axial. pos tion. at he. an i w uld be undesirable itlwould; result. in.- tocviolcn aspiri g. force against the; pi ton. with the can at; one of. its extreme positions. and in too. tight. a for e fo quickac ion in the. ther. extreme. position... Instead, with the spring-f nee tainer 42' in a fixed position a spring tension most. suitable for general. usemay be. predeterminedand maintained.

In order. to insure. the: presence of. atomizing, air at the nozzle. theifinger 31,. contacts, the, air valve, stem, 33 before. the. head. 32 01 the. materialgvalve. is, movedrearwardly. by the. end wall. of theboreof. tri g r. 3.0.. l

Placing the. two. air mletconnections in parallel arrangement beneath the cylinder'contributes, with the balance of. the design to. providing, a spray sun. of, a compa readily per ble n-- struction.

Although a preierred embodim nt or: th inventi'on. is. shown. and: described he ein. it. is t be. understood: that. mo ifica ions m y, e. made therein without: departing from the spirit and scope of the invention asset; forth in. the. append'edclaims.

What is claimed is:

1. In a spray gun of the class described wherein a fluid operated needle valve for controlling the material discharge is employed, a cylinder at the rear end of the gun, a piston mounted in the cylinder and normally standing at its forward end, a rod projecting axially from the piston through the front end of the cylinder, two air inlet passages with their inlet openings facing rearwardly lying side by side beneath the air cylinder and parallel therewith, the first of said passages leading to the front end of the cylinder for delivering piston actuating air, the second of said passages leading to the forward end of the spray gun for delivering material atomizing air, a normally closed valve in said second passage and having a forwardly projecting stem exposed at its forward end, said valve being rearwardly movable to open position, an arm projecting downwardly from said piston rod in ad- Vance of the cylinder and laterally extending end portion on said arm operable to contact said stem and open said valve when the piston is moved rearwardly.

2. In a spray gun of the class described, a reciprocally movable trigger member movable in one direction by spring action and in the other direction by fluid pressure, said member having a cylindrical chamber therein with a restricted opening at its forward end and an associated opening on a side adjacent its forward end, a reciprocally movable needle valve for controlling the material discharge of the gun, said valve having an enlargement at its rear end for introduction into said chamber through said openings and a coactive engagement with the inner forward wall of said chamber, a spring thrust forwardly from its support at the rear end of said chamber toward the rear end of the valve to normally hold the valve in forwardly projected position relative to said trigger member, a spring retaining disc between the spring and the enlarged end of the valve and a restriction in the inner wall of the chamber preventing the disc from reaching the forward end of the chamber with which the openings communicate, whereby the disc is not forced by the spring into the space normally occupied by the enlarged end of the valve when the valve is disconnected from the trigger member.

3. In a spray gun of the class described, separable spray head and body parts, the spray head having separate passages for the discharge of material to be sprayed and for atomizin air and having at its rear end a centrally disposed rearwardlv projected nipple and a rearwardly opening inlet above said nipple and in connection with the air passage, a needle type control valve for the material discharge projecting rearwardly from the head through said nipple, said body including a cylinder with a forwardly and rearwardly extendin axis, fluid pressure controlled means reciprocally operable in said cylinder and connectable with said needle valve, said body having laterally spaced arms projecting forwardly from the lower portion of the forward end of the cylinder, said arms having upwardly turned end portions embracin opposite sides of the spray head, a bridge between said ends abutting the rear end of the spray head and having two openings, one above the other, the upper one registering with said inlet opening, the other receiving said nipple, and means extending through the upper opening into said inlet opening for releasably retaining said head and body in assembled relation.

DONALD J. PEEPS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,751,608 Titternore et a1 Mar, 25, 1930 1,962,911 Roselund June 12, 1934 1,969,205 Carr et a1. Aug. 7, 1934 2,059,706 Paasche Nov. 3, 1936 2,060,894 Potter Nov. 17, 1936 2,107,726 Bramsen et a1 Feb. 8, 1938 2,227,161 Shelburne Dec. 31, 1940 2,344,055 Osborn Mar. 14, 1944 2,362,834 Larson Nov. 14, 1944 2,366,121 Martin-Hurst Dec. 26, 1944 2,371,546 Roselund Mar. 13, 1945

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