US2466734A - Apparatus for controlling the coating applied to an object - Google Patents

Description

APPARATUS FOR CONTROLLING THE April 12, 1949. T. E. mm 2,466,734

COATING APPLIED TO AN OBJECT I Filed May 4, 1945 5-Sl 1e9ts-Sheet 1 .0 Io o e I V o loll v u l j I! uvvszy rox. N By Tho/7211551 0; 519

April 12, 1949. T. E. PIAIZZE 2,46 3

.APPARATUS FOR CONTROLLING THE =COATING APPLIED TO AN OBJECT Filed May 4, 1945 7 3 Sheets-Sheet 2 IN V EN TOR.

3 Sheets-Sheet 3 mmvron 1'. E. Pl'Azzlz APPARATUS FOR CONTROLLING THE COATING APPLIED TO AN OBJECT A ril 12; 1949.

Filed May 4, 1945 I Pia/ 6, BY

Patented Apr. 12,1949

APPARATUS FOR CONTROLLING COAT- lNG APPLIED TOAN OBJECT Thomas E. Piano, Mount Vernon,

Ohio, assignor, I

by mesne assignments, to Shellmar Products Corporation, Mount Vernon, Ohio, :1 corpora- .tion of Delaware Application May 4, 1945, Serial No. 591,883 20mm. (on. 91-53) The present invention relates to improvements in the industry of coating materials. More particularly, it pertains to a device for regulating and controlling'the application of viscous coating solutions to moving objects, such as a rotating roller which thereafter transfers the coating directly to a traveling web, or by regulating and controlling the coating solution after it has been applied to a web, by a combined operation of metering and evenly distributing the metered solution to such moving objects, and the provision of such a device is a principal ob- Ject of the invention.

It is generally known in' the coating industry that conventional mechanical devices, used in the art of coating Webs such as paper, cellophane, and the like, with liquid materials of various viscosities, are not adaptable for obtaining coatings of a uniform thickness and a smoothness to a high degree'of accuracy. This isparticularly true, for example, of devices employing rotating rollers and stationary bars as a means for applying coatings of viscoussolutions. When rotating rollers are used for metering purposes, extreme accuracy of thickness almost becomes an impossibility due to the fact that the non-controllable imperfections of the rollers, which are purely of a mechanical nature, reflect directly upon the film formation of thecoating solution on the webs at the time of its application. Diflicultly controllable factors which contribute largely to inaccurate coatings involve, for example, eccentricity of the periphery of the roller surface which usually cannot be held to less than .001". Also, circumferential crowding of the 'coating material, in the form of ridges, is characteristic of viscous materials when applied to smooth faces of rotating rollers. Another factor involved is uneven transfer of coating solutions from one roller surface to an0ther,'or from a roller surface to a web, because the coating material has a tendency to become stringy at the point where the surfaces leave each other.

Several well known devices have been used in combination with coating application methodsin attempts to overcome such difficulties and disadvantages as the foregoing. As a rule, such devices consist of stationary members, or so-called doctor blades, designed in various-configurations. Most of these devices consist of highly smoothed and curved surfaces terminating in a. sharp edge over which the freshly coated web is made to drag. The web is then deflected over the edge so as to apply a gentle amount of pressure. The sliding action of-the objects against the smooth 2 sharp edge seems to flatten down the coating to a smooth ,and even appearance, but these devices are, not capable of-metering the coating to a. uniform thickness and'even distribution over the entire web, or selected portions thereof.

Generally, it is an object of the invention to overcome the foregoing difficulties and disadvantages and to provide a device which is economic of manufacture, simple yet sturdy and durable 'of construction, which will operate with comparative freedom from wear and tear, and is so designed as to afford a wide range of regulation and control of a viscous coating solution so that the same can be applied to a roller, or to a web, in a manner heretofore never accomplished, without serious concern of eccentricity of roller surfaces, unevenness and thickness of paper, vibration factors, or any other factors like those heretofore enumerated which might be the cause for an uneven coating.

In its broader aspects the invention has for its object the provision of a device, for regulating and controlling an amount of viscous coating solution applied to a moving object, which utilizes a'metering and smoothing member along which the viscous material will flow with means disposed on the member which rest against the object to be coated while holding the member in spaced apart position from the object to permit the solution to flow, thereby metering the amount thereof to be applied to the object, and means along which the viscous solution continues to flow after metering, whereby to smooth and spread the same into 'a coating of substantially even thickness against a moving object.

More specifically, the invention has for its object a device of the foregoing type which utilizes a relatively thin and flexible metering and smoothing blade along which the viscous material will flow, the blade having a plurality of projections of substantially equal magnitude disposed along the blade which rest against a moving object, such as a rotating roller-or traveling web, and hold the blade in spaced apart position from the object permitting the solution to flow and thereby metering the amount to be-applied' ,to the object, and an extension portion on the solution is being applied to brace the web against viscous solution which is permitted to flow between the coated object and the blade.

Other objects of the invention will inpart be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 illustrates an elevational view of a metering and smoothing blade as applied, for example, to a rotogravure applicator type of roller before transferring a viscous coating to a traveling web;

Fig. 2 is a plan view of a fragment of a metering and smoothing blade of the type depicted inFig. 1;

Fig. 3 is a front elevational view of the blade portion shown in Fig. 2;

Fig. 4 is a transverse sectional View of the' blade taken along the lines 4-4 of Fig. 2;

Fig. 5 is an enlarged view of the metering and smoothing blade illustrating its operation; Fig. 6 is an enlarged plan view of a portion of the bottom of such a blade illustrating the flow of viscous solution along and away from the same;

Depending upon the nature or the work to be done, the blade should be anywhere from .001 of an inch and over in thickness. The distance between dots can be anywhere from .010 of an inch to one inch, and each projection can be anywhere from .001 to .050 of an inch in thickness.

In Fig. 1 such a blade illustrates the manner in which a viscous .solution I 4 in a tank, or reservoir, I5 is metered and smoothed upon an applicator roller 16 operating on the rotogravure principle. The rotation of the roller causes the solution to flow along the bottom of the blade Fig. '7 is an end elevational view of a device I for controlling and regulating a blade such as that shown, in Fig. 1, illustrating the blade in operation directly against a traveling web; and

Fig. 8 is a front elevational View, partly in section and with parts broken away, of the device illustrated in Fig. 7.

Referring more particularly to the drawings, there is shown a metering 'and smoothing'blade 10 secured in a holder Ii. Such a. blade preferably is made of a springy material of light thickness so as not to apply excessive pressure. Transversely oi the blade I0 is a plurality of projections 12. Preferably, these projections are made by distorting sections of the blade to form beads, or buttons, which are generally circular in cross section. It should be observed that these beads, or buttons, are of substantially equal magnitude in the degree of projection from the top surface of the blade and that they are disposed 'in substantially transverse alignment of the I0 and between the projections I! because these projections, where they are in point of contact with then'oller l6, hold the blade in spaced apart relationship with respect to the roller, readily permitting the solution to flow under the blade. By virtue of the arrangement and size of the projections, a viscous solution can be metered in any amount desired. However, as more clearly illustrated in Figs. 5 and 6, the viscous solution is permitted to sweep past the projections and against the extended portion I3 of the blade, the latter smoothing the solution in an equal distribution andeven thickness as it leaves the extreme edge H of the blade 10.

When practicing the method of application shown in Fig. l, a traveling web l8, such as paper, cellophane, or the like, is run against the applied coating 19 between the nip of a pressure roller 20, and the coating 19 is then tran ferred to the web; As soon as the coating leaves the extended portion of the blade l3, where it has been smoothed and evenly distributed as illustrated in Fig. 6, the material is coated onto the web surface in the same condition. There are no appreciable voids, spaces, irregularities, stringiness or the like, as so often is produced by conventional devices, and this results in a very desirable application of coating material of superior quality. This is particularly noticeable where such webs, when transparent, are laminated to similar webs. Conventional devices invariably apply coatings which, because of the various irregularities and imperfections, such as those above mentioned, can readily be detected when such transparent laminated Webs are held against light rays. Obviously, such improperly coated surfaces do not give maximum qualities of adhesion, moistureproofness, or whatever quality is desired for such coated webs. Particularly, in the so-called duplex or laminated web, in addition to the fact that such qualities are absent, there is an insufliciency of desirable transparency characteristics, and the webs take on the appearance of translucency' rather than transparency. I It is to be noted that it is within the contemplation of the invention to cause the metering and smoothing blade to be moved along a stationary object to be coated although holding the blade stationary against a moving object is preferable.

A smoothing and metering blade constructed in accordance with the principles of the present invention is particularly advantageous in that it can readily be adjusted to regulateand control I practiced directly upon a traveling web, illustrating the versatility of the coating device. The same type of apparatus, of course, can be used to hold the blade in position against a roller as illustrated in Fig. 1. However, this device will be described in connection with the regulation and control of a coating solution applieddirectly to a traveling web running against a supporting roller.

In its preferred form the micrometric adjusting device comprises a main shaft 2| journaled in bearings 22, 22, secured to the side frames of a coating machine 23, 23. At one end of this shaft is a worm wheel 24, meshed with a worm 25, on a shaft 26, under control of a hand wheel 21. Keyed to the shaft 2| is a two-part carriage, or header members, 28, 29, disposed adjacent each side frame, one header carrying a worm wheel 30 keyed to a shaft 3|. The worm wheel 30 is meshed with a worm 32 on a shaft 33 under the control of a hand wheel 34. This train of gears provides the micrometric control for two gear segments 35, 35. These segments are pivotally mounted at 36 and 31 on the two-part carriage, or header members, 28, 29, respectively. The gear segments have gear teeth 38 which mesh with splined or toothed portions 39, 39, on the shaft 3| Mounted between the toothed segments 35, 35, is a blade holder 40 which holds blade ill in fixed position, either against an actuating roller such as that indicated at iii in Fig. 1, or against the web 4| in Fig. 7. It will be observed that the web 4| is supported, for example, by a roller 42 disposed against the opposite surface of the web in the area where thesolution is to be applied to brace the web against the pressure of the blade.

It should be noted that the projections l2, on the blade l0, should be in line contact transversely of, and in contact with, the web 4| supported by the roller 42, and that the pivot points 38, 31, for the segments 35, 35, are in axial alignment with the line of contact between the object to be coated and the line of projections l2. The same condition would, of course, obtain where the projections are in contact with, for example, the applicator roller "5. This is of importance in regulating the micrometric control of the device because the blade can now be tilted around the projections utilizing them as pivot points. It will be seen that the tilting of the blade I0 about the projections |2 enables an operator to regulate the flow of viscous solution which fiows under the blade to an object in motion, such as the web 4|, or the roller I6, by rocking the blade toward or away from the object at the point where the solution begins to flow to the projections. The distance which the projections space the blade, from either the web or a roller, will meter or control the amount of solution which is permitted to fiow to the surface to be coated. By turning the hand wheel 34 the segments 35, 35, can gradually be swung in either direction so as to control the separate smoothing action of the extension l3 of the blade ID to any degree required.

In order rapidly to move the blade into and out of operating position, the hand wheel 21 is utilized to turn the shaft 26, worm 25, and worm wheel 24.

The actual finishing action of the coating aperation occurs at the moment when the material leaves the edge ll of the blade which reduces to a minimum the hazards of stringing, irregularities, uneven distribution, and other disadvantageous characteristics.

It will thus be seen that the objects hereinbefore set forth may readily and efliciently be attained. and since certain changes may be made in the above article and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a, device for regulating and controlling an amount of viscous coating solution applied to a moving object, the improvement comprising a relatively thin and fiexible metering and smoothing blade along which said viscous material will flow, a plurality of projections of substantially .equal magnitude disposed transversely along said tion on said blade constituting the section directedbeyond said projections to said terminating edge along which said solution will continue to flow after the same has been metered by said pro-'- jections, thereby to smooth and spread the same into a coating of substantially equal distribution and thickness against said object.

2. In a. device for regulating and controlling an amount of viscous coating solution applied to a moving object, the improvement comprising a relatively thin and flexible meteringand smoothing blade along which said viscous material will fiow, a plurality of projections of substantially equal magnitude disposed transversely along said blade marginally inwardly from its terminating edge, to rest against said objectand to hold said blade in spaced apart relation with respect to said object to permit said solution to flow therebetween and thereby to meter the amount thereof to be applied to said object, andan extension portion on said bladeconstituting the section directed beyond said projections to said terminating edge along which said solution will continue to flow after the same has been metered by said projections, thereby to smooth and spread the same into a coating of substantially equal distribution and thickness against said object, a holder to support said metering and smoothing blade in contact with said object to be coated, and means to tilt said blade about said projections while using the latter as a fulcrum point, thereby to regulate and control the amount of said solution which is permitted to flow upon said object.

THOMAS E. PIAZZE.

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

UNITED STATES PATENTS Number Name Date 491,861 Smith et a1. Feb. 14, 1893 1,799,002 Case Mar. 31, 1931 2,024,284

Grower Dec. 17, 1935

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