US2404000A - Coating machine and method of coating - Google Patents

Description

R m N E w 5 Sheet-$heet 1 Juiylfi, 1946. G. 1.. SHERWOOD COATING MACHINE AND METHOD OFCOAI'ING Flled July 24, 1940 Juiy 16, 1946. G. L. SHERWOOD COATING MACHJENE AND METHOD OF COATING 5 SheeLs-Sheet 2 Filed July 24, 1940 IITI, 1.. HHHHH H mnnnnnunu Ill lllll/IIIlK-llllllilll INVENTOR Zamfifierwm Eufiy 3,6, 39% a a... SHERWQOD 2,404,000

COATING MACHINE AND METHOD OF COATING Filed July 24, I940 5 Sheets-Sheet 3 III] Hill INVENTOR.

July 16;, 39 O a L SHERWQQQ 2,404,000

COATING MACHINE AND METHOD OF COATING Filed July 24, 1940 5 Sheets-Sheet 4 1N VENTOR.

11$ iwfi G. L. SHERWOOD 4,

COATING MACHINE AND METHOD OF COATING Filed July 24, 1940 .5 Sheets-Sheet 5 INV ENT OR.

Patented July 16, .1946

UNITED STATE -S PATENT OFFICE.

COATING MACHINE AND -METHOD OF COATING Glenn L. Sherwood, Benton Harbor, "Mich, as-

signor to Kaywood Corporation, Benton Harbor, Mich.,' a co'rporation of Michigan Application July 24, 1940, seria1 No. 347.i35

I iiolaiins.

This invention relates 'to coating machinery andmore particularlyto machinery of this" kind for coating a strippr ribbon of 'inaterial, such as metalffor use afterward in the construction or manufacture of any desired Structure or article of commerce. 7

Generally stated, the object of the invention is to .provide an improved machine and an improved method for use in the manufacture of Ventianblinds orsiiriilar things, and to provide a machine and method for this purposethat will substantially or materiallyreduce the cost of production of the Venetian blinds "or other things, by simplifying and expediting the coating of the slats from which the blinds or other things are made. M V I More specifically considered, the object of the invention is toprovide an improved machine and m'e thod for coating a strip or ribbon of cold rolled steel with enamel or similar material, or with paint of any desiredcharacter, in such a manner that the enamel or otherliquid material will dry smoothly and effectively on th surface of the steelstrip or ribbon, sc -that the latter may then becut into lengthssuitable-for use as the slats or. Venetian blinds-or-other things.

.2 are 'wound asthey'coine from the drying ovenof the s'aidmachine' or apparatus.

Fig. 101s a vertical fragmentary section on'line lll-"l inFig. 2 of the drawings.

A thus illustrated, a plurality of reels 1 is mounted'on'a' singlehorizontalshaft 2, the ends 7 ofwhich latter rotate in'bearin'gs 3 of 'any suit- It is also an object to provide certain nove l details and. teatures of construction and combinations tendi'ng to increase the general eiiiciency and desirability of an apparatus and method'of this particular-character. W l H 'To the foregoing and other useful ends, the invention consists in matters hereinafterset forth and claimed and shown in the accompanying drawings, in which Fig. 1 is a side elevation of amachine pr apparatus embodying the principles-of the invention, showing certain portions thereof broken away for convenience ofilluStration.

'Fig. 2'is a rear elevation ofthe structure-shown in Fig. 1 of the drawings.

Fig.3 is-a vertical sectional view on -l-ine 3 -3 in'FigLZ of the drawings, on a larger scale.

'Fig. 4is a vertical section of a portion of the apparatus on line "4--4 in Fig. 3 of the drawings. Fig. 5 is an enlargedsectional view online 5-5 i'n' Figfi2 of the drawings. 1 I A Fig.6 is a lperspectiveof the twoportions of the device shown in Fig. 5 of the drawings. N

Fig. 7 is an enlargedhorizontalsectionon line 'I-TinFig. 5 ofthe drawings. V

Fig. 8 'is a'vertical section on'line 8-8 in Fig. 7 ofthe drawings. H

Fig. 9 is a perspective of the reels or spools uponwliich'the coated strips or ribbons of steel able character. The thin steel strips or ribbons 4 are carried on these reels and are pulled downwardly from said reels through the enamel or paint-E in the container 6 and around the idlers 1 an'dthen upwardly through the drying or baking oven 8, which latter is disposed vertically in a vertical transverse plane and is of suifiicent height to ins'urethe desired drying or baking of the enamel or paint on'the strips. The coated and partially dried strips then move over the idlers 9 mounted at the top-of the machine or apparatus and are then pulled downwardly around the'i'dler Ill and then vertically downward inthe oven 8 until they travel around the driving roll 'Il onthe horizontal shaft [2, which latter is'the main driving shaft of the machine. By looking at Figs. 1 and 3, it will be seen that the downwardly moving coated portions of the strips moveoutside of the oven 8 for a distance before engaging the driving rolls I I, and-the coated strips then pass under the rolls H and are woundon a multiple spool rotating about an axis I3 which rotates about a horizontal axis and is driven from-the shaft [2 previously mentioned, so that in this way the strip are pulled through the machine or apparatus and are then individually wound tight in the circumferential grooves or spaces of the spool, as indicated more clearly'in Figs. 9 and 10 of the drawings.

'lfhatis thegeneral plan of the apparatus and method employed, --and the best results are obtained, it is found, when the oven heat'isma-intained at a-temperature anywhere from two hundied and seventy to three hundred degrees Fahrenheit, so that the strips orrlbbons remain approximately one-half an hour in the oven. There is approximately eight hundred feet of strip or ribbon on the reel-l, preferably, and it preferably requires about eight hours to run a reel of the cold rolled sheet steel through the machine, so that it will finally emerge very smoothly and very satisfactorily coated with the enamel or paint or any other liquid material. Preferably, of course, that a plurality of'strips or ribbons can :be 'run through the machine at the same time, and coated in difierent colors,

to be coated, with a difierent color of paint or reducing gear 2 i enamel in each container. These enamel containers are set in a water tank 14, and the water is preferably maintained at a temperature of about one hundred and twenty degrees, so that the paint or enamel will have that temperature while the strips or ribbons are passing through.

After the strips or ribbons come off the reel l, they pass through a brake device comprising rolls [5 driven at a lower rate of speed than the tape or ribbon is moving, and the strips or ribbons are held against these rolls by the felt brake device l6 which is controlled by the tension spring or spring H, and at this juncture it will also be observed that the reel I is governed by a band brake 13 which is under the tension of the sprin or springs i9, shown in Fig. 3 of the drawings.

Everything is preferably driven from the shaft 4 tween which the tape or ribbon moves upwardly, it being observed that the plate 34 is fastened to the side walls of the paint or enamel container. The plate 35 is subject to the action of the spring or spring 36, through the medium of levers 31, so that the fiat strip of metal is momentarily made trough-shaped, as shown at 38 in Fig. '7 of the drawings. In other words, it becomes partially tubular, and anything tubular, or partially so, is much stiffer and more rigid than a sheet or strip of metal in perfectly fiat form. In other words, the plate 34 is concave, and the plate 35 is convex, in horizontal cross-section, and this I2 previously described, in the manner indicated in Fig. 1 of the drawings, and this shaft is preferably driven by an electric motor 29 through a of any suitable character, whereby the said driven elements of the machine will each be given the predetermined speed necessary or desirable for doing the work in the required manner.

Rolls 22'under the control of the springs 23 press the coated and dried ribbons against the under Sides of the roll H, as shown in Fig. 3 of the drawings, and while this is sufiicient to pull the tapes or ribbons through the machine, it will be seen that the spool or reel 13 is also driven by the roller 24 which is belt-driven from the shaft l2 previously mentioned.

A heater 25, of any suitable character, is provided to furnish heated air to the oven, and this is preferably accomplished by using a vertical airjacket 25 around the smoke-pipe 27, which latter may carry off the products of combustion from the heater, assumin that oil or gas or fuel of some kind is burned in the said heater'to provide the required heat. The heated air in the jacket 26 is discharged through pipes 28 into the upper portion of the heater, and the motordriven fan 29 then sucks the heated air downwardly and through the pipe 36, where it is then discharged back into the said heater. Of course, some fresh air enters the bottom of the heater at 3| to compensate for losses.

Thus, looking at Fig. 1 of the drawings, it will lie-seen that the coated tape or ribbons travel a distance in the atmosphereoutside of the oven,

after leaving the rollers 9, and then travel down- "wardly inside of the heater, and then outside of the latter before reaching the driven rollers H, for it is found that in this way the enamel or paint or other material is more satisfactorily dried and hardened;

Paintis supplied to the different containers 6 in any suitable or desired manner, as by simply pouring it in by hand, and each container is preferably provided with a baiiie 32 to prevent the ripple from reaching the strips or ribbons of metal or other suitable material.

Preferably, the multiple spool may be lifted out when it becomes entirely loaded with the coated strips or ribbons of metal, so that the said strips may then be removed and cut into sections of desired length for Venetian blind slats, or

means that the strip or ribbon becomes momentarily shaped like a shallow trough in cross-section, and in that way it gains rigidity enough to prevent vibration thereof.

Moving at a comparatively slow rate of speed, theascending portions of the tape or ribbons are, in effect, wiped and freed of surplus paint or enamel at the surface of the body of liquid in each container. In this way, there is'no downward flow of the enamel or paint on the ascending portions of the ribbons, and the liquid is dried and baked in very smooth condition on each ribbon.

It has been found that when the tape or ribbons move about eighteen inches a minute, good results have been obtained, and good results have been obtained with cold rolled steel two inches wide and about eight-one-thousandths of an inch in thickness. Each strip or ribbon is about one minute in the paint bath, preferably, although this would probably change or vary for different kinds of enamel or paint or other liquid, and the same is true of the time required in the drying and baking oven. The proportions and the general height of the machine or apparatus "should be, therefore, such as to insure the above figures.

a With the apparatus and method as shown and described, the coating of the tape or ribbon is such that they can be permanently pressed into trough-shape, to make them rigid, as in the case of slats for Venetian blinds, and while the metal is thin-and'comparatively light, the slats for blinds made in this way are surprisingly strong and rigid. The forming of the strips or ribbons of metal in-this way, by converting each one into a shallow trough, is done without correcting or in any way damaging the dried, baked enamel or paint thereon. It thus becomes possible to make the coating step of the process a practically continuous one, as the coating is done on relatively long strips instead of on short ones.

Obviously, there is considerable room or latitude for changes in the construction of the apparatus shown and described, without going outside the scope andspirit of the invention. For example, long rollers might be used as a substitute for some of the sets of individual rollers. Preferably, the apparatus is substantially or practically vertical, so that the tape or ribbons travel upwardly and then downwardly. This makes for a practically minimum amount of floor space necessary for the machine or apparatus, but it is conceivable that the tape or ribbons could be made to travel horizontally instead of vertically, by using a different relative arrangement of the elements of the machine or apparatus.

An important thing to observe is that while the coating is done by a dipping process, it is true that the motion of the article or thingbeing dipped is never reversed in the paint bath, as it travels through the latter by continuous motion and without-any. interruption or reversal thereof.

-theobjeot to becoated travels'continu- .ously. in: one .direction and it rises so slowly outzof thepaint or enamelbath,*that the liquid. is spread evenlyanduniformly in a thin filmover thesurfaces .of'the metalror other'material, and this filmof liquid is not disturbed by anyjoltingor jarring or vibration of the 'strip or ribbon 'of metal, with the result that whenthe'coatedtape .or'strip is finally wound on'the .reel 33, the film of enamel orpaint isperfectly smooth and uniformv in thickness, and completely dry. Things of this'kind can be coated byspraying the painter enamel on :them, but there are many :diiiiculties and objections involved in .spraying which are completely eliminated .or obviated .by a dipping process of .the kind ishovmiandsdescribe'd. :For example, spraying oftnarrow orfsmall articles or objects is usually' accompanied by a serious waste of the liquidmaterial, whereas with the dipping process shown and described, thereis absolutely no vwaste-of the painter enamel. In addition, spraying involves the atomiz'ing of the liquid, and if the latter contains a idrier of one kind or another, the fine particles of'the liquid may become too :hard before they strike .the surface 'of the article to be coated. With the multiple reels shown and described, the plurality of strips or ribbons can be coated simultaneously, each with a diiferent color or shade, and thisis possible without :increasing the height of the machine. The tape 'or ribbon is kepttaut and held against distortiomwith the one exception that it is momentarily curved in "cross section immediately before .it emerges from the surface of the liquid, and this slight momentary distortion tends to prevent vibration of thestrip or ribbon,'-which is desirable inasmuch asvibration-mi'ght disturb the filmpf'liqui'don the ribbon. But with the latter held against any vibration, the film is of uniform thickness and is absolutely stable, so that it dries 'or bakes in a perfectly smooth condition and with a glossy surface that is entirely free from roughness or unevenness. Therefore, ifthe strip :or ribbon is run at too high a speed, it will carry vup an'excess 'of liquid that will then run back down 'and'streak the surface of the film. But when the ribbonis' runat such-a slow rate of speed that it carries upward no excessliquid, a thin'film' is insured of uniform thicknessand with no unevenness of the surface thereof.

It-will be observed that while thestripor ribbon with the film of paint or enamel thereon is moving in one direction, the heated air is moving, in the oppositedirection, inasmuch as the said tape or ribbon moves upwardly in the oven 8, while the heated air in the latter moves downwardly. SIn 'thisway, any given spot on the strip or ribbonis subjected to steady and changing supply of :heated air, during its course oftravel throughthe oven. In this way, the strip or ribbon encounters the minimum temperature when it enters the lower end of the oven, and then encounters the maximum temperature-when it entersthe upper portion of the oven. This, of course, means the upwardly travelingportion of the tape or ribbon, for while the latter ultimately passes-outside of the oven and through the ordinary atmosphere, and then downwardly a distance within the oven, it will be seen that the greater course vor distance of travel is upwardly within the oven.

If the several strips or. ribbons are being coated to become the slats of Venetian blinds-it is ob- Vi'ous that a suitable or desired means can be .used for curving the dry coated: material transversely, so :that his slightlyitrough shaped in cross :section, and that any suitable means can be employed for cutting the strips into lengths suitablefor'the Venetianblinds, and that this cuttingoperationican beperformed before or even after the strip or'ribbon is'permanently curved in :cross section.

Thus;the;dipping process for coating the sheet steel or other suitable material becomes continuous, in efiect, instead of'being intermittent as itwouldbe if .the material was cut into suitablexlengths and :thereafter dipped and coated. The enamel, paint or otherlliquid material employedshouldbe of 'any well known kind that is toughi and 'ipliable, 'when'dried; so that the forming.'of the strips WillInOt crack or injure the coating .thereon.

The foregoing'isra description of the apparatus in "what might :be called its simplestform, assuming that the strips Jorribbons are all movi'ng simultaneously, fromfsupplyireels thatare allon one shaft, .and finally'to storagereels that are a1l1on another shaft.

l'Howeven'iin actual practice; it is found :preferabletohave the-supply reels operating separately and independently of each other, and to have the storage reels upon'which' the 'coate'dstrips or ribbons arewoun'dialso operating -separately and independently of eachother, whereby the amount of 'windior coiled-up strip or ribbon maybe considerably differentfonithe different reels or drums, or on thespoolsa's they may becalle'd.

i-For'that purpose,ithere are'then as many supply "reels 1'! as there are stripjsor ribbonsyoras there are'p'aint or enamel containers "forholcling theiliquid. A1S0, for that purpose, there'are as many .istorage reels or drums 33 as there are strips or ribbons, or as there are liquid containers.

That means that there are as many band'brakes It as there are supply reels or drums on'the axis 2. The separate and independent storage reels 33 practically float on the roller 24 and the roller 39, which latter is merely an idler, the roller '24 being driven at a higher speed than the feed, in orde to keep the strips or ribbons taut on the reels 33, and this compensates for the difierence inspee'd of the tape or ribbon when it begi'nsto wind up on 'a reel, and its speed when the reel is nearly full. As shown more clearly in Fig.9, the framing 40 has some transversechannel irons M and '42 thereon, provided with pins 43 that keep the reels 33 properly separatedand upright on the rolls24 and '39. In this way, the supply rels and the storage reels can be used in'different ways, and one reel can be running a small job while another reel is running a large job, and other things can be done, quite obviously, that could not be done 'if all the supply reels were rigid'with each other, and if all the storage reels were'rigid with each other. Of course, thespeed of alltheistrips or ribbons is maintained at a certain predetermined degree by the fixed speed of the roll I I, and its idler roll 22, which are maintained at a predetermined given speed inorder to insure the proper timing of the apparatus, not only as to the timing of thestrips or ribbons in the bath, but also in the oven. Obviously, there must be no disturbance that would .cause ripple in the bath, and thelength of time that the strips or ribbons are in the oven, orbeing dried and hardened, must be predetermined to insure the. proper drying andahardening of the thinfilm of liquid material 'on .the strips or ribbons. :It will alsobeseenthat there are preferably as many springs 23, and spring-pressed rollers 22, as there are ribbons or strips to be coated, for it is better to have the feeding grip individual for each strip or ribbon, for in that way there is compensation for any difference in thickness as between the strips o ribbons, and the machine may be workingssimultaneously on both relatively thick and relatively thin strips or ribbons, and at this juncture it is to be observed that there are as many friction brakes I6 as there are rolls 15, in the preferred form of the apparatus.

Of course, the timing and temperatures mentioned are merely those that have been found to be proper for a, particular enamel which has been used for coating the strips. Of course, some enamel is baked at a temperature as high as six hundred degrees Fahrenheit, and all the other conditions depend more or less on the type of material used, for some enamels or paints dry and bake quickly while others require more time, and hence the distance of travel and the temperature of the elements and other factors of that kind will vary according to the type of material used. The invention, therefore, is not limited to any particular temperature or timing or length of travel, as that will vary more or less in accordance with different conditions.

What I claim as my invention:

1. An apparatus for continuously coating a metal ribbon with a liquid coating composition which comprises a container for the liquid coating composition, the largest dimension of which container is man times smaller than the length of the metal ribbon, means for continuously guiding the metal ribbon into and out of the liquid in the container at a slow even speed whereby to uniformly coat the metal ribbon with a thin smooth film of the coating composition and means for continuously drying the film of coating composition so formed on the metal ribbon, said drying means including an oven supplied with heated air moving downwardly therethrough and guide means associated with said oven for mov-' ing the coated ribbon from the container for the coating composition upwardly through the oven, then for a short distance outside the oven, and then downwardly again inside the oven and then again out of the oven by a movement laterally therefrom at a point located a substantial distance above the lower end of the oven.

2. An apparatus for continuously coating a metal ribbon with a liquid coating composition which comprises a container for the liquid coating composition, means for guiding the metal ribbon into and out of the liquid in the container at a slow even speed, whereby to uniformly coat the metal ribbon with a thin smooth film of the coating composition, and means located adjacent the surface of said liquid in said container for providing the ribbon with an arcuate form transversely of its length as it leaves the body of coating composition in said container whereby to prevent vibration of the coated metal ribbon as it leaves said body.

3. An apparatus for continuously coating a metal ribbon with a liquid coating composition which comprises a container for the liquid coating composition, means for guiding the metal ribbon into and out of the liquid in the container at a slow even speed, whereb to uniformly coat the metal ribbon with a thin smooth film of the coating composition, and means for preventing vibra-.

tion of the coated metal ribbon as it leaves the body of liquid coating composition in said container including means having a slot therein which slot is arcuate transversely'of the line of travel of said metal ribbon, through which slot the metal ribbon passes, the said means having the arcuate slot therein being located within said container for the coating composition a short distance below the upper surface of the coating composition in said container whereby the coated metal ribbon has a temporary arcuate form transversely of its length as it leaves the body of coating composition.

4. An apparatus as described in claim 3 further characterized in that the arcuate slot is formed between a pair of members having cooperating arcuate surfaces, one of said members being fixed and the other being yieldably pressed against said fixed member with sufiicient force to give said coated metal ribbon said temporary arcuate form transversely of its length as it leaves the body of the coating composition.

5. An apparatus for continuously coating a metal ribbon with a liquid coating composition which comprises a container for the liquid coating composition, means for passing the metal ribbon through the liquid in said container at a slow even speed, whereby to uniformly coat the metal ribbon with a thin smooth film of the coating composition, said means for passing the metal ribbon including a roller driven at a slow even speed engaging the metal ribbon after the coating is applied and drawing the metal ribbon through the coating bath at said slow even speed and said means for passing the metal ribbon also including a supply reel and a second driven roller having a uniform peripheral speed slightly less than that of said firstnamed roller and positioned at a place in the path of travel of said metal ribbon between said supply reel and said container the metal ribbon being maintained in engagement with said second driven roller by means resiliently urging said metal ribbon against said second driven roller whereb the portion of metal ribbon extending between said second driven roller and said first driven roller is placed under tension.

6. An apparatus for continuously coating a metal ribbon with a liquid. coating composition which comprises a container for the liquid coating composition, means for guiding the metal ribbon into and out of the liquid in the container at a slow even speed, whereby to uniformly coat the metal ribbon with a thin smooth film of the coating composition and means for preventingvibration of the coated metal ribbon as it leaves the body of liquid coating composition in said container including means having a slot therein which slot is arcuate transversely of the line of travel of said metal ribbon, through which slot the metal ribbon passes, the said means having the arcuate slot therein being located adjacent the upper surface of the coating composition in said container whereb the coated metal ribbon has a temporary arcuate form transversely of its length as it leaves the body of coating composition.

7. In a method of making short lengths of coated metal ribbon permanently set in an arcuate form transversely of their length the step which comprises first continuously coating a relativel long ribbon of the metal before subdividing said metal into lengths and before providing said permanent arcuate set, said coating being applied by continuously guiding the ribbon of the metal into and continuously drawing said ribbon vertically upwardly out of a body of liquid coating composition in a container at a slow even speed, providing said ribbon with an arcuate form transversely'bf its length over a portion of its path of travel extending from a point a substantial distance within the body of liquid coating composition to a point a substantial distance beyond where said ribbon leaves the body of liquid coating composition and continuously drying the film of coating composition so formed on the long metal ribbon, said coating composition being maintained at uniform temperature and uniform composition during the coating operation.

8. A method for continuously coating a metal ribbon with a liquid coating composition which comprises guidin the metal ribbon into and drawing said ribbon vertically upwardly out of a body of the liquid coating composition at a slow even speed and providing the metal ribbon with an arcuate form transversely of its length over a portion of its path of travel extending from a point a substantial distance Within the body of liquid coating composition to a point a substantial distance beyond where the metal ribbon leaves the body of liquid coating composition.

9. An apparatus for continuously coating a metal ribbon with a liquid coating composition which comprises a container for the liquid coating composition, means for maintaining the coating composition in said container at a uniform temperature throughout the coating operation, means for guiding the metal ribbon into and vertically upwardly out of the liquid in the container at a slow even speed, whereby to uniformly coat the metal ribbon with a thin smooth film of the coating composition and means for preventing vibration of the coated metal ribbon as it leaves th body of liquid coating composition in said container including means having a slot therein which slot is arcuate transversely of the line of travel of said metal ribbon, through which slot the metal ribbon passes, the said means having the arcuate slot being located adjacent the upper surface of the coating composition in said container whereby the coated metal ribbon has a temporary arcuate form transversely of its length as it leaves the body of coating composition.

10. A method for continuously coating a metal ribbon with a liquid coating composition which comprises guiding the metal ribbon into and out of a body of liquid coating composition at a slow even speed and providing the metal ribbon with an arcuate form transversely of its length over a portion of its path of travel extending from a point a substantial distance within the body of liquid coating composition to a point a substantial distance beyond where the metal ribbon leaves the body of coating composition.

11. A method for continuously coating a metal ribbon with a liquid coating composition which comprises continuously guiding the metal ribbon into and drawin said ribbon verticall upwardly out of a body of the liquid coating composition in a container at a slow even speed, providing the metal ribbon with an arcuate form transversely of its length over a portion of its path of travel extending from a point a substantial distance within the body of liquid coating composition to a p int a substantial distance beyond where the metal ribbon leaves the body of coating composition and continuously drying the film of coating composition so formed on the metal ribbon, said coating composition being maintained at uniform temperature during the coating operation.

GLENN L. SHERWOOD.

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