US2574584A - Apparatus for the surface coating of web materials - Google Patents

Description

Nov. 13, 1951 J. l. NASMITH 2,574,584

APPARATUS FOR THE SURFACE comma OF WEB MATERIALS Filed May 18, 1948 2 SHEETSSHEET 1 mvEN-roR JOH 1. NASMIH u "/I/ 4& AGENTS I I l I I I I l NOV. 13, 1951 J NA$M|TH 2,574,584

' APPARATUS FOR THE SURFACE COATING OF WEB MATERIALS Filed May 18, 1948 2 SHEETS-SHEET 2 INVENTOR Patented Nov. 13, 1951 APPARATUS FOR THE SURFACE COATING OF WEB MATERIALS John Irving Nasmith, London, England, assignor to Vickers-Armstrongs Limited, London, England, a British company Application May 18, 1948, Serial No. 27,809

In Great Britain Ma! 20, 1947 5 Claims.

The invention relates to improved method of and means for the surface coating of one side of reeled paper or similar material as unwound, from a supply reel or its equivalent to articles to be coated or to re-winding means.

For example the invention is particularly usein! in connection with the gumming of reeled paper, being fed to work-pieces such as cartons, cardboard boxes and the like on machines for lining and/or covering such containers. However, provided the coating material has a certain amount of tackiness or has a viscosity such as obtains with normal liquid glue or paste applied to paper or the like as aforesaid, the coating material may comprise substances other than glue. Likewise instead of paper, fabric or cellulose materials can be employed.

In the present generally adopted methods of summing strip material a glueing roller is mounted in bearing with its lower peripheral part immersed in the adhesive contained in a suitable reservoir, the strip material being lapped over the upper portion of the periphery of the roller. The roller is revolved at an indeterminate speed by the strip material when pulled over it, picks up an indeterminate and widely varying amount of adhesive which is brought into contact with the paper surface. An excessive amount of adhesive is always applied which subsequently, has to be scraped off to get an evenly distributed film, involving considerable waste of adhesive,

:much of which cannot be recovered, and also much cleaning of scrapers and clearing away of drying adhesive from the apparatus is required. Further, an excess is absorbed by the coated material, often weakening it, spoiling its gloss and finish, causing excessive shrinkage in drying, and the material has to travel a considerable distance before it, and its surface film, are in a suitable dried condition to apply to the work or to rewind.

Another known method is to mount in conjunction with the reservoir a positively driven slovv revolving glue feed roller, and to strip this, or pick up" adhesive therefrom, by a faster running second or' stripping roller also positively driven, but only intermittently, when the strip material is pulled through the apparatus over a portion of the periphery of the second roller. This largely eliminates the defects of the first method described, but a considerable amount of mechanism is required, including a clutch, and further there is not exact relationship between the movement of the paper and the surface speed of the roller. As the coating film is now always 2 very thin, the evenness of the film cannot be satisfactorily maintained.

It is the object of the present invention to obviate these disadvantages, and to provide a 5 much simpler method of obtaining a constant, thin, and even film of the coating material on the web.

According to the invention a method of surface coating web material consists in transferring the adhesive or other fluid coating material to the web of paper or the like tensioned for the purpose from a positively driven feed roller in contact with the adhesive material by means of an idler form of stripping roller with its periphcry out of contact with the feed roller, but sufficiently close to transfer the required quantity of coating material from the feed roller to the stripping roller, the stripping roller being rotated in unison with the varying speed of the web by the direct action of the arc of contact therewith of the said tensioned web.

In carrying the invention into practice a slow running driven feed roller dips into the coating material in a reservoir, and a light, balanced,

and relatively small diameter stripping roller is provided, mounted in anti-friction bearings which are adjustable relative to those of the driven feed roller, to enable the thickness of the film transferredto the stripping roller to be adjusted. The

latter is no longer positively driven, but rides freely in its anti-friction bearings. The action of stripping the surplus fluid from the feed roller provides a continuous force always tending to revolve the stripping roller, and if this force is sufficient will actuallydo so if this roller is not otherwise influenced.

This force is always sufiicient to reduce the inertia effects due to starting, or accelerating, the speed of rotation of this roller to a negligible amount, but is not sufiicient to interfere with the functional control of its motion, induced as now to be described. The reel of material is suitably mounted and lightly braked to provide a constant small essential tension iifthe strip as it is unwound. Any convenient means, not forming any part of this invention may be adopted to provide this tension. When the machine is in operation the web is so guided as to lap over a considerable are, approximately half of the peripherx of the stripping roller, and these guiding means are convenientlyprovided in such form that, when the machine is stopped for a period, the web can be removed from contact with the stripping roller to prevent it adhering thereto. The are of lap, the small tension pro- .shown partly submerged in a reservoir 2 for the;

the same, and vary together according to the speed at which the web is pulled through the apparatus which in practice may vary widely. An even, thin, uniform film of the coating material is thus transferred to the web at all times, without any further distribution being necessary, no additional travel of the web for drying is -required, and it is always available, properly conditioned, for application to the work. The shrinkage on drying is reduced to a minimum, and no absorption sufficient to spoil the original finish of the web is possible.

The invention provides a mechanically very simple method of attaining all these desirable results, for intermittent coating operations such as are required for instance in the case of box banding machines, together with simplicity and cleanliness of operation. I

In order that the invention may be clearly understood as readily carried into effect drawings are appended hereto illustrating somewhat diagrammatically an embodiment thereof, and wherein,

Figure 1 is a broken sectional and elevation showing the arrangement of feed and stripping 2 by reason of the slight spacing oi the peripheries of the rollers I and I, the roller I can be adapted to merely strip the surplus adhesive iluid from the feed roller I, and it is found in practice that if the roller I is left free to rotate idly on its bearings, without the .webv .II engaging it, the

roller 8 will 'be' rotated simply by'r'eason of they influence of the coating of adhesive fluid of the positively driven roller I. In other words. the action of stripping the surplus fluid from the feed roller provides a continuous force always tending to revolve the stripping roller.

The web II is fed from a reel which is very lightly braked to provide a constant small but rollers, and the means for adjusting the paper or the like into engagement with, and away from.

the stripping roller.

-.mover driving a belt carried over a pulley I Figure 2 is a broken plan view of Figure 1.

view showing the paper or the like being coatedv by contact with the stripping roller, and

Figure 4 shows the paper moved away from the stripping roller.

Referring to the drawings the feed roller I is glue, this feed roller being mounted on a spindle I -joumalled at its ends in bearings in a frame part I of the coating machine and driven at a slow speed, e. g. forty R. P. M. from any suitable prime of the spindle.

A stripping roller 6 is provided slightly above the reservoir '2 parallel with the feed roller I, its

ends being closed by caps I which are concentrically recessed to accommodate bearings I each :receiving a thrust member 9 centered upon the tapered inner extremity of the appropriate one of a pair of center pins I0 fixed relatively to the frame I.v The feed roller I is adjustable towards and away from the roller I by mounting the spindle 3 of the roller I in bearing blocks II sliding in slots II' and receiving the threaded -ends of adjusting screws I2 held against axial displacement and having their unthreaded ends 'suitably fitted with adjusting knobs or screwdriver grooves in wellknown manner; The; periphery of the stripping roller I is always slightly spaced from the periphery ot the feed roller I, the spacing being so adjustedthat the thickness of the film transferred tothe striprotated by the tractive eirort oi the web II, in

firm contact with the roller.

That is to say the stripping roller is not positively driven, but rides freely on the bearings. i- It: will be appreciated from .the -foi'tgoinmthat essential tension in the web as it is unwound from the reel, and any obvious and well known means may be provided to obtain this braking action on the supply'reel.

The web II is guided so as to lap over the periphery of stripping roller I through an appreciable are, which is nearly; approximately-mall of the periphery of-the stripping'roller, andsjor this purpose the frame [carries a-pair pilike arms II pivoted at their lower ends to pivotpms I! fixed in the frame I and cranked between their ends to afford an arcuate corner II normally resting on the adjacent bearing pins IgI aforesaid. These arms carry center-pins and II for a'horizontal pair of rollers or rotary rods II and 20 respectively over which the web I3 is drawn underften'sion. v lltris preferred to provide at the free-ends of the arms II a relatively smaller roller- II to'guide the" "on II from the reel under the upper rollerre; of

It will be appreciated from the foregoing f t when the machine is stopped the web Ii cam-lie removed from contact with the stripping -rcnse-I to prevent it "adherin'gthereto, simply by swinging the two arms I4 away from the rollersl to occupy the position shown in 4i This, the web is prevented from becoming adhered'fto the stripping roller I during idle p'eriodsif Further, it will be appreciated that only a small tension is necessary for obtaining requisite rotation of the stripping roller applying an even, thin film of the coatin material to the web.

I claim; a 1'. Apparatus for the adhesive surface of a web such as e. g. paper strip'to be fed-to workpieces to which the web is to be adhered, comprising a main frame, an idler formflof ping roller supported rotatably by said frame, a positively driven ieed roller supported rotatably by said main frame and driven pendently of the stripping roller, a reservoir for the adhesive in which the feed roller-is immersed, a guide frame i'or "the'wewpivotally supported at one end and free'at-its' other e'nd. its'free end being above its-pivoted end sci-that said guide frame can be'lowered to 'an operative -'position'where the web guidedthereby' wili la'y .over the periphery of the stripping muss-sun -can be swung upwards about-its pivotal support to bring the web away from the strippin .two guide rollers for the web material supported acrossthe guide frame between its pivoted 'a'lil free ends and, in the'operative positionof said guide-frame, having their'axes in a-plane" "is not outside the space between the axesd'flle :stripping .and feed :rollers so thatl-the weir must .engage and negotiate a .substantiat-arcioifilie stripping roller from one guide rnlleri'othe'oflaer,

the guiderroller nearer the.- ireemnd the aerated web before it reaches the stripping roller and the other guide roller guiding the coated web material to the article to be covered by the web material so that the idler stripping roller is driven at a peripheral speed at all times equal to the rate of travel of the web independently of the feed roller solely by the substantial are of contact of the tensioned web with the stripping roller and the traction of the said article, bearing members for the stripping roller and feed roller carried by the main. frame and so related with each other that the stripping roller has its pe= riphery spaced from the periphery of the feed roller by an amount such that with the normal viscosity of the coating material it will be fed to the stripping roller by the surface tension of the coating material on the feed roller.

2. Apparatus for the adhesive surface coating of a web material such as e. g. paper strip to be fed to workpieces to which the web material is to be adhered, comprising a main frame, an idler form of stripping roller supported rotatably by said main frame, a positively driven feed roller supported rotatably by said main frame and driven independently of the stripping roller, a reservoir for the adhesive in which the feed roller is partly immersed, a web guide frame pivotally supported at one end and free at its other end, so that said guide frame can be lowered to an operative position where the web guided thereby will lay over the periphery of the stripping roller and can be swung upwards about its pivotal support to bring the web away from the stripping roller, two guides for the web material supported across the guide frame between its pivoted and free ends and, in the operative position of the frame, being disposed in a plane between the axis of the stripping roller and the axis of the feed roller and with the stripping roller spaced between them so that the web must engage and negotiate a substantial arc of the strippin roller from one guide to the other, the guide nearer the free end guiding the web before it reaches the stripping roller and the other guide guiding the coated web to the article to be covered by the web so that the idler stripping roller is driven at a peripheral speed at all times equal to the rate of travel of the web independently of the feed roller solely by the substantial arc of contact of the tensioned web with the stripping roller and the traction of the said article, bearing members for the stripping roller and feed roller carried by the main frame and so related with each other that the stripping roller has its periphery spaced from the periphery of the feed roller by an amount such that with the normal viscosity of the coating material it will be fed to the stripping roller by the surface tension of the coating material on the feed roller.

3. Apparatus according to claim 2 wherein the said guide frame comprises a pair of arched arms across which are supported the said two guides and between which guides the stripping roller is located in spaced relationship when the guide frame is in the operative position, said arms being pivotally supported at one end on a common axis spaced from the stripping roller and disposed beneath the part of the periphery of the stripping roller contacted by the web, their other ends being free and disposed above the said pivotal axis, the said guides comprising a pair of guide rollers under which the web is drawn to cause the web to arch under tension over the stripp roller.

4. Apparatus according to claim 3 wherein said arched arms normally rest upon bearing members for and concentric with the stripping roller.

5. Apparatus according to claim 4 wherein an additional guide for the web is disposed across said arms between the free end of the guide frame and the adjacent one of said pair of guide rollers over which additional guide the coated web is drawn to afford a guide for the web when the guide frame has been swung away from the roller.

' JOHN IRVING NASMITH.

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

UNITED STATES PA'I'ENTS Number Name Date 219,963 Mather Sept. 23, 1879 1,913,022 Dennis June 6, 1933 2,070,600 Jennett Feb. 16, 1937 2,093,347 Beecher Sept. 14, 1937

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