US2319476A - Coating machine - Google Patents

Description

APatented May 1s, 19453 g Utri-Iran *Par-'ENT f OFFICE e L I e l Y coarrzisiicnmn i i y p Bannay, Los Angeles, oeuf. Application January 6, 1939, Serial No. 249,574 l (Cl. el-so) 4 Claims.n

This invention 'pertains to improved meansfor tons and various other containers itis desirable to render thehboxes and containers water rel sistant;- Various lacquers, resinous coating compositions or compositions containing waxes. latex', rubber 'condensation products, etc., have been applied. :In mostins'tances these resinous, rubbery or waxy compositions contain a volatile. solvent at the time they are vapplied to the paper or other stock from which `the box or container is to be made. Numerous problems are encountered in the applying process, among which is theproblem of forming a lm of uniform thickness. Anotherproblem is thecontrol of solvent vapors.

seallngor lcoating'compositions may be applied to individual cards or ,pieces of `fibrous material. These and other objects, uses, advantages and l adaptations ofthe invention will become apl e like. In t l the-manufacture of boxes, hoods for bottles, car- 4 parent to those skilled in vthe vart from' the following detailed description f certain illustrative forms. f A u In order toltfacilitate understanding, reference will-be had to the appended drawings, in which:

j Fig. 1 diagrammatically illustrates an arrangement of elements whereby a continuous strip oi fibrous material may be coated on bothsides.

` Fig. 2 is an enlarged view of one form of appli'- i apparatus for use in applying a sealing coating kThe present vinvention `is directed towards means whereby av continuous, uniform, homogeneous'fllm of coatingmaterial may be applied without permitting large quantities of solvents to be lost. The apparatus is'particularly adapted to the application of a lm or coating to coni tinuous strips of paper or the like. j

`Generally stated, the invention comprises supplying a coating liquid in the form of a'continuous stream through a narrow aperture onto the lsurface to be coated and maintaining yielding at right angles to the aperture." In this manner a uniform` film` of the coating composition is `applied to the surface of the strip, a portion of Vthat surface (opposite saidl aperture). being in direct contact with a body of coating liquid.

An object of this invention, therefore, is to provide an improved apparatus for coating pa per, wood and other` fibrous materialsl with a sealingor coating composition. i i

Another object is to provide anV apparatus' whereby continuous s'trips of fibrous material may be coated on oneor both sides with a water resistant or other sealing or coating composition in `a continuous manner.

A further objectA is to provide means whereby to individual blanks of material to be coated.

Fig. 4 is an enlarged vertical section through a portion of the device/shown in Fig.r3.

The arrangement shown in Fig. l is particular- 1y adapted for use in coating a continuous strip of materialonboth sides with a suitable sealing" or coating composition. A tank for this sealing `solution is indicated at I0. As stated hereinbefore, the sealing solution may comprise a. solution of gums,` resins, lacquer-s, waxes and rubber or rubber-like products in a suitable solvent. Or-

dinarlly, relativelyv volatile solvents are ein- `ployed.` An acryloid type ofl resin or synthetic vplastic in a volatile solvent such as butyl acetate, is an example of one -form of coating solution. I'he coating solution from tank I0 mayrthen be circulated by a pump lithrough lines I2 into a' back to the tank I0. In this manner a continuousohead of coating solutionis maintained in the a g `surge tank I3. A line or lines I8 connect'the ylower portion of the surge tank Ilwith the applicators Hand I5. n. Y

Fig. 2 is an enlarged` vertical section through one 'of the applicators, say applicator I'4. As there ,shown the applicator is in the form of a horizontally extending tube, one end of which is' in communication with the supply line i8 and uthe other end of which is preferably' closed. Longitudinally extending along the tube I4` Ais a slot or aperture 2li. Opposing said slot or aper- Vil of the applicator. A stationary supporting member 22 is diagrammatically illustrated, the presser plate 2| being attached to the bolt 23 extending through the stationary support. Spring means 24 yieldably press the presser plate against' the aperture.

A supply reel 26 of continuous strip material over a suitable roller, such as the roller 21. and

'then past the applicator I4, the strip material -even though ysuch continuous strip reverses its direction. For example; between the` rollers3l and 32 it travels from right to left whereas between the rolls 33 and 34 it travels from left to right. Thereafter the continuous strip material may pass over the rollers 35 and 36 and be discharged from the drier. This strip material now passes past the applicator I5 which applies an- ,other film of sealingand coating material to the opposite side of such continuous strip 28 wherey to be coated may discharge the strip of material adapted to coat individual sheets or blanks of fibrous material. at-60 and such blank passes through feed rolls 6 I; the blank may be fixed tov progress from left to right (Fig. 3) in anypsuitable manner, as forij example by means of a conveyor belt or belts. feed rolls, or thev like. As the leading edge of the blank 60 contacts a pivoted key 62 in the form lmember 68 acts as a valve and is provided with a discharge slot 10 and an inlet opening 1I. The inlet opening 1| is always in communication with the main supply linev 12 which, for -purposes understood later, may be a flexible tube or hose connecting the applicator 63 with a supply tank 13. When the solenoid 66 is actuated and the lever 61 is pulled down, the discharge opening 10 of the rotary valve member 68 places the,

- interior of the applicator in communication with upon the strip passes over a roll 31 and returns u to the drier wherein it is trained over rollers such as the rollers 38, 39, and 4|. Eventually the continuous strip is discharged from the drier 30 and collected upon a take-up reel 42 which is positively driven. During the entire operation the continuous strip material 28 is maintained under tension and is progressed past the applicators and through the drier by reason of the pull exerted upon the take-up reel 42. If desired, certain of the rollers, such as the rollers 31 and 39, may be frictionally driven so as to facilitate the forward travel of the continuous strip through the machine.

' By again referring to Fig. 2 it will benoted that the trailing ,edge of the aperture 20 is relatively narrow, the exterior of the tubular casing of the applicator being milled out slightly as indicated at 50. In other words, the trailing edge adjacent the longitudinal aperture 20 preferably has an action similar to that of a knife for smoothing out the applied composition or solution. The

' 1 and z-wm be evident many one skilled in the art from the description given. It is to bek noted that the coating solution is suppliedto the applicators under a' constant gravity head so that no pulsations or changesin pressure exist. Furthermore, the disadvantages incidental to spraying or paintingbyhand are not encountered,v

the entire system being totally enclosed. The

- surface of the paper 28 is in communication with the interior of the applicator I4 and a relatively thin but solid body of. fluid is in contact with such surface through the slot 20. Ordinarily the slot 20 may measure from about 0.05 to 0.1 inch in, width, it being understood that the Width yof this slot will depend upon the viscosity and other characteristics of the sealing solution and the head or pressure at which it is supplied to the interior ofthe applicator.-

. and cut back as shown at 85.

, Figs. 3 and 4 particularly relate to a device 75 the aperture`69.

The position of the original contact 62 is correlated with the lag of the relay 6,5 so that by the time the leading edge of the blank 60 assumes a position immediately below the slot 69 of the applicator 63, the rotatable valve 68 has been moved into its operative 4position and the sealing` fluid is being discharged through the slot 69. As soon as the trailing edge of the blank 60 releases the contact 62, the solenoid 66 is deenergized. and the valve returns to its original closed position (indicated in Fig. 4) by reason of the spring 14.

In order to accommodate blanks 60 of varying thickness, the entire applicator 63 may be pivotally suspended as up`0n the lever arm 80 from a stationary support 8|. One end of the lever arm` may be held down by means of a set screw 82. B y adjusting the set screw 82, the entire applicator 63 may be caused to rise or fall and thereby positioned at` any desired height with respect to the table, conveyor belt or other plane through which the blanks 60 move.'4 4Since the storage tank 13 may also be stationary. the flexible tube 12 accommodates for differences in operative height assumed by the applicator 63.

As in the case of the applicator described in connection with Figs. 1 and 2, the trailing edge adjacent the discharge slot 69 is relatively thin s groove adjacentthe rear edge ofthe opening or port acts as a doctor knifevand prevents accumulation of coating composition in frictiona1 contact with the freshly coated sheets.

The coating compositions may therefore be applied to one or -both sides of acontinuous strip or to pieces of sheet material. The coating compositions may be water proof, water-resisting, waxy, oi' a nature adapted to strengthen the fibrous sheet material, or of a nature permitting the sheet material to become adhesive upon the further application of solvents, heat or heat and pressrure.` Some coating compositions need not contain a. volatile solvent at the time of their application to the sheet material. When compositions of the type described by Abrams in Patent #2,054,115 are applied, for example. it may be desirable .to use `a steam jacket or other heating One such blank is indicated 1 asians means around the applicators for the purpose of liquefying the composition and facilitatingcoating. Coatings of this last mentioned type are particularly of advantage where the coated material is to be used in making bottle hoods and containers since blanks cut from such coated sheet material can later be preheated and then pressed to the desiredvshape, the composition acting as a thermoplasticV or vulcanizing substance bonding the folded or pressed portions together without n they use of' added adhesives. Resinous composll tions in hot or melted condition can also be applied by the method or apparatus of my invention.

A Iclaim:

1. In an apparatus for coating sheet material with protective coatings, an applicator comprising a tubular member provided with a longitudinally extending slot having substantially parallel walls, said slot forming anapplicating port defined by edge portions, a gradualLv curving surface on said tubular member leading to lthe front edge portion of said slot, said tubular member material across the slot` and virtually tangent sheet material and coating applied thereto,

whereby said last-named edge of the slot is thin and adapted to act as a smoothing knife edge;

3. In anapparatus for coating sheet material4 with protective `coatings:l an applicatorcomprisving a tubular member provided with a longitudinally extending slot in communication with the interior of said member, the slot having plane, substantially parallel walls, the slot forming an `applicating' port defined by edge portions integral with said tubular member a gradually curving surface on said tubular member leading to the front edge portion of the slot; a reentrant surface adjacent the rear edge of the slot and parallel to the'slot. said reentrant surface defining a narrow rear edge portionto the slot, such narrow rearedge portion being adapted to act as a I smoothing knife edge: means fordrawing sheet to the applicator at said slot; and means for supi plying liquid coating to-the tubular member and being provided with a re-entrant curved surface f adjacent the rear'edge portion oi said slot, said re-entrant curved surface being parallel to said slot but spaced therefrom whereby said rear edge Iportion is rendered narrow and is adapted to act as a smoothing knife edge. a rotary valve in said tubular member, said `valve being adapted t'o open and kclose said applicating port, means for moving sheet'material along a line of travel past ,said port, and means operated by sheets or material advancing toward said port for said rotary valve to open said port. 2'. An apparatus for'applying coating in liquid form to the. surface ofsheet material comprising: an applicator having a transversely rounded surface provided with a slot extending lengthwise 1 thereof, means for supplying liquid coating material to the slot, means for drawing sheet material substantially` transversely to theaxis of the actuating slot by gravity. l.

4. In an apparatus for coatingsheet material with protective coatings: an applicator compris'- ing a tubular member provided with a longitudinally extending slot having substantially parallel p walls, said slot forming an appiicating port del fined by edge portions, a gradually curving surface-on said tubular member leading to the front edge portion of said slot, said tubular member being provided with a reentrant curved surface adjacent the rear edge portion of said slot. said reentrant curved surface being` parallel to said slot .but spaced therefrom whereby said rear edge slot and in contact with the edges thereof and substantially tangentialiy to the rounded surface of the applicator, said rounded surface having a longitudinally extending recess formed therein i and parallel to such slot and closely adjacent that edge of the slot which is last in contact with the portion is rendered narrow and is adapted to act as a smoothing knife edge; a'rotary valve in said tubular member, said valve being adapted to open and close said applicating port: a lever arm pivL' otally supporting said applicator;- means for ad-f justably positioning the lever arm and applicatorV with respect tola line of travel oi'sheet material; means |for moving'sheet material along the line `oftravelnastsaidport:andmeausoperatcdliy sheets of material advancing toward said port for actuating said rotary valve to open said port.

DON RAY.

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