US3163555A - Method and apparatus for coating flexible sheet material - Google Patents

Description

umnon AND APPARATUS ma comm: FLEXIBLE swam MATERIAL Filed Aug. 11. 1961 J. H. BROWN Dec. 29, 1964 2 Shoots-Sheet 1 METHOD AND APPARATUS FOR comma FLEXIBLE SHEET MATERIAL Filed Aug. 11. 1961 J. H. BROWN Dec. 29, 1964 2 Sheets-Sheet 2 IN V EN TOR. JHCKHELCKDDU 20m METHOD AND APPARATUS FOR COATING FLEXIBLE SHEET MATERIAL Jack Heywood Brown, Beverly, Mass, assignor to Swift & Company, Chicago, 111., a corporation of Illinois Filed Aug. 11, 1961, Ser. No. 130,863 9 Claims. (Cl. 117105.3)

I This invention deals generally with an improved method and apparatus for applying a coating of substance to a surface of sheet-like items. More particularly this invention provides an improved method and apparatus for flowing a coating of substance onto only one surface of flexible sheet material, such as leather or the like.

In the handling of sheets or webs of material, particularly in the leather industry, a number of processes require that one surface of the material be given a coating of a fluid substance. While liquid material may be transferred to a surface in a number of ways, for example, by spraying, wiping, or rolling, one of the most versatile methods for applying the coating substance is to flow it as a substantially continuous curtain onto the leather or other material.

While the general method of flow coating articles has been practiced in other industries, and apparatus for coating articles in this manner have been available, a common disadvantage has heretofore prevented adaptation of the method and apparatus to processing flexible sheet material. The method heretofore has usually resulted in the coating substance contacting more than one surface of the processed material. In the processing of such material, particularly in processing leather, it is desirable that the coating substance reach only the surface of the material selected for finishing. However, prior methods and apparatus have involved the use of a series of continuous ribbons for supporting the articles to be coated which themselves run through the curtain of coating substance. Accordingly, in those areas of the conveyor which were not covered by materials being processed, the conveyor ribbons received the substance and in turn later transferred such substance to the underside of succeeding material.

Attempts to overcome the above described disadvantage have involved additional apparatus and expense, a further disadvantage itself. For example, the continuous ribbons have been run through a cleansing bath or spray, thus requiring an additional cleaning step at substantial cost of both operation and equipment.

Certain apparatus have, however, been devised heretofore to overcome these disadvantages insofar as rigid articles have been concerned. In the processing of stiff or rigid items, it has been possible to project each item across an open area, where the curtain of coating substance is located, directly between two separate conveyors or conveyor runs operating in the same plane. This technique has not been practical with flexible sheet-like material due to the fact that no suitable method or means of projecting the material across a suflicient space had been devised. If such material was not supported along its travel through the curtain of coating substance, it would fall downwardly either short of or into the coating substance before reaching the second conveyor or conveyor run. This difliculty is further aggravated by the force of the falling coating substance which tends to knock the material passing therethrough downwardly.

Therefore, it is a principal object of the present invention to provide a method and apparatus overcoming the above-noted disadvantages and deficiencies of the prior art.

It is another object of this invention to provide an improved method and apparatus to pass flexible sheet mate- United States Patent l 3,163,555 Patented Dec. 29, 1964 rial through a continuous curtain of coating substance without depositing or transferring any of such substance to the underside of the material.

It is a further object of this invention to provide an improved method and apparatus to project flexible, sheet material across an unsupported distance wherein a substantially continuous curtain of coating substance is confined to fall on one surface of such material.

Basically this invention comprises the method of propelling a sheet of flexible material along a path of support and inclining the path slightly in advance of the curtain of coating substance. The support of the material is discontinued from a point on the inclined portion of the path, through the curtain, and recommenced beyond the curtain of coating substance.

Apparatus for carrying out this method is basically comprised of a first conveying means terminating in a means for inclining the path of a sheet traveling thereon just in advance of the location of a means for delivering a curtain of coating substance. A second separate conveying means adapted to receive the material after passing through the curtain of coating substance, at a level lower than that of the inclining means, is positioned just beyond the curtain delivering means to remove the material as it is coated.

Further objects and advantages of the present invention will become apparent from the following disclosure taken in conjunction with the drawings wherein:

FIGURE 1 is a perspective view of the apparatus of this invention with the coating head shown in phantom; and

FIGURE 2 is a sectional elevation view of the apparatus showing an item being coated as its forward end is unsupported and with the position of the item when the forward end is resupported shown in phantom.

According to the present method, flexible sheet material, such as leather, is supported and conveyed along a path in a given direction (from left to right in the drawings) at a preferable feed rate of to 200 lineal feet per minute. At a convenient location along the location of such path the sheet material is inclined above the horizontal at an angle of up to about 15 and supported further at that angle for a short distance. Thereafter, support of the moving material is removed for a short gap, preferably no greater than 2 to 2 inches, wherein a substantially continuous curtain of falling coating substance is applied to the upper surface of the moving material across its width. At the far side of the abovementioned gap, and preferably at a level slightly below the highest level reached on the inclined and supported path prior to the unsupported movement, the underside of the material is re-engaged and the support thereof is renewed. Preferably the underside of the material is resupported and simultaneously pulled or otherwise urged in substantially the same direction at a slightly greater lineal speed than the feed rate so as to assist the leading edges of succeeding items of material in spanning the aforementioned gap, and preventing such leading edges from slipping backward into the coating substance.

It has been found that in performing the above-de scribed method coating substance may be supplied to a 60-inch wide curtain at a rate of from 3 to 10 gallons per minute varying with the particular nature of both the coating substance and coated material, and the feed rate of the material being coated.

Referring to the drawings, it may be seen that an apparatus devised for carrying out the aforementioned method upon leather is mounted upon a frame generally 10 including a pair of spaced parallel rails 11 and 12. A first conveying means generally 14 (at the left side in the drawings) comprises an endless belt 15 extending from a power-driven roll (not shown) about a terminal roll 16 mounted on an axle 17 journaled in a pair of bearings 18, 19. The bearings lid, 19 are in turn supported on brackets 21, 22 respectively, each of which are adjustably supported on the rails 11 and 12, respectively, by a pair of bolts 23 extending through slots 14 in each rail. Conventional belt-tightening apparatus, not shown, is preferably situated along the lower run of the endless belt to take up any slack therein. The position of the terminal end of the first conveying means generally 14 may readily be adjusted by loosening the bolts 23 and sliding brackets 2t, 22 to the desired position, and thereafter resecuring the the bolts 23.

A pair of stanchions 27, 28 are also secured, for example by welding or riveting, to the brackets 21, 22, re spectively. These stanchions support an inclined plate 29 parallel and co-extensive to the roll 16 of the first conveying means generally 14. The plate 29 is hinged to stanchions 27, 28 at its lower edge 30 closely adjacent the upper surface of endless belt 115. As may be seen best in FIG- URE 2 the upper edge of the plate 29 is turned downwardly as a flang 31; and the angle of inclination of the plate is adjustable by means of a pair of depending wings 32 containing arcuate slots 33 which are engaged by an adjustment nut 34 threaded on a bolt fixed on stanchions 27, 28.

A transfer means comprising a discontinuous roll generally 37 is supported on the frame 10 spaced to the right of the flange 31 of plate 29. The transfer roll generally 3'7 consists of a plurality of discs 38, each preferably having roughened friction surfaces 39, fixed in equally spaced locations on an axle 40. The friction surfaces 39 of the.

discs 38 may most conveniently consist of knurling, but could also comprise a plurality of short radial pins or other well-known frictional means to assist positive engagement of the underside of material being processed.

Axle 40 is in turn journaled in a pair of bearings 41, d2 which are also adjustably supported upon rails 11 and 12, respectively. The bearings may be seen in the drawings to be mounted upon short lengths of channel iron 43 slidably mounted upon rails 11, 12 by means of bolts extending through narrow slots 45 in the upper surface thereof.

The location of the transfer roll 37, along the frame generally it), may be adjusted in the same manner as with the terminal roll 16 of the first conveyor 14. In practice it is desirable to maintain a horizontal distance of up to about 2 to 2% inches between flange 31 and the surface of discs 38. This distance is adjustable within about the foregoing range according to the feed rate, weight per running foot, and flexibility of the material being coated. Increases in any of the above three factors generally requires shortening the distance between the flange 31 of incline plate 29 and the transfer roll generally 37.

It may also be noted in the drawings that the uppermost point on the transfer roll generally 37 is maintained at a level slightly below that of flange 31. The level of the top of transfer roll 37 is also preferably below the upper run of belt 15. Accordingly, sheet material being fed across the plate 29 will follow an arcing trajectory across the gap and into engagement with transfer roll 37.

It is also preferable to operate the transfer roll generally 37 at a surface speed slightly in excess of the work piece feed rate. Accordingly the discs 38 may most advantageously be driven directly from the axle 17 of roll 16. This can be accomplished by means of a pulley 47 secured to axle 17 and a second pulley 48 secured to axle dtl. and a drive belt 49 extending thercbetween. According to the respective diameters of roll 16 and disc 38, the diameter of pulleys 47 and 48 are selected by well-known principles to operate the transfer roll generally 37 at a slightly greater surface speed than conveyor 14.

A substantially conventional flow coating head generally 51 is located above the space between flange 31 of plate 29 and the transfer roll generally 37, Such a device includes an orifice or weir 52 extending the width of the apparatus parallel to the axes of roll 16 and transfer roll 37. In operation a substantially continuous curtain of fluid substance 53 will fall from the orifice 52 into a sump pan 54 located within the frame generally 10.

A second conveyor generally 56 is positioned at the discharge side of the transfer roll generally 37 (to the right in the drawings). The second conveyor 56 comprises an endless belt 57 trained about a roll 58 mounted upon an axle 59; which in turn is journaled in a pair of bearings 60, 61 adjustablymounted upon rails 11 and 12 by means of bolts 62 extending through slot 63 in the rails. The endless belt is trained about another powered roll, not shown, at a distance from roll 58.

It should be apparent from the foregoing description that in operation sheets or webs of flexible material may be placed upon the first conveying means generally 14 with the surface to be treated disposed upwardly. Such material is then supported along a path toward the curtain of fluid 53 and inclined upwardly across plate 29 just before reaching the curtain. Inertia of the material will carry it across a curving unsupported trajectory through the curtain of fluid 53 and onto the transfer roll generally 37 and thence to the second conveyor generally 56 and away from the coating apparatus.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are in dicated in the appended claims.

I claim:

1. An improved method for coating sheet-like items of flexible material, said method comprising: propelling a single thickness sheet of flexible material at a certain speed along a substantially horizontal given path in a given direction; upwardly inclining said path slightly at a location along said direction; supporting said sheet from its underside along said path at said location; discontinuing support of said sheet for a relatively short distance in said direction beyond said location; recommencing sup porting said sheet beyond said distance, in said direction; and coating only the upper surface of said sheet by flowing downwardly from above said sheet a substantially continuous vertical curtain of substance upon the upper surface of said sheet in the distance such sheet is unsuported.

2. An improved method for coating sheet-like items of flexible material, said method comprising: propelling a single thickness sheet of flexible material at a certain speed along a given path in a given direction while spread to expose the surface to be coated upwardly in a substantially horizontal attitude and expose the underside of said sheet downwardly; upwardly inclining said path slightly at a location along said direction; supporting said sheet from its underside along said path at said location; discontinuing support of said sheet for a relatively short distance in said direction beyond said location; recommencing supporting said sheet beyond said distance in said direction, said support being recommenced at a level below the highest point of said path at said location; and coating only the upper surface of said sheet by flowing downwardly from above said sheet a substantially continuous vertical curtain of coating substance upon the upwardly exposed surface of said sheet in the distance said sheet is unsupported.

3. An improved method for coat-ing sheet-like items of flexible material, said method comprising propelling a sheet of flexible material at a certain speed along a given path in a given direction while spread to expose the surface to be coated upwardly in a substantially horizontal attitude; inclining said path slightly at a location along said direction; supporting said sheet from its underside along said path at said location; discontinuing support of said sheet for a relatively short distance in said direction beyond said location; recommencing supporting said sheet area-sue beyond said distance, in said direction, while attempting to propel said sheet in said direction at an increased speed, said support being recommenced at a level below the highest point of said path at said location; and flowing a substantially continuous curtain of coating substance upon the upwardly exposed surface of said sheet in the distance said sheet is unsupported.

4. The method of claim 3 wherein the material coated is leather.

5. An improved apparatus for coating only the upper surfaces of sheet-like items of flexible material under a substantially continuous curtain vertically falling of coating substance, said apparatus comprising: first conveying means for supporting and propelling items of flexible material at a certain speed along a substantially horizontal path in a given direction; upwardly inclining means for directing the path of said items upwardly at a slight angle to said first conveying means, said inclining means being disposed at a location in said direction so as to support said items from their undersides; a second moving conveying means for supporting and propelling said items from their undersides, said second conveying means being spaced in said direction from said inclining means so as to leave items passing therebetween along said path unsupported across a short horizontal distance; and supplying means to flow a substantially continuous vertical curtain of coating substance upon said sheet, said supplying means being located above the space between said inclining and second conveying means.

6. An improved apparatus for coating only the upper surfaces of sheet-like items of flexible material under a substantially continuous vertically falling curtain of coating substance, said apparatus comprising: first conveying means for supporting and propelling items of flexible material at a certain speed along a path in a given direction while said items are spread to expose the surface to be coated upwardly in a substantially horizontal attitude; upwardly inclining means for directing the path of said items upwardly at a slight angle to said first conveying means, said inclining means being disposed at a location in said direction so as to support items from their underside; a second moving conveying means for supporting and propelling said items from their underside located at a level below the highest point on said inclining means, said second means being spaced in said direction from said inclining means so as to leave items passing therebetween along said path unsupported across a short horizontal distance; and supplying means to flow a substantially continuous vertical curtain of coating substance upon the upwardly exposed surface of said sheet, said supplying means being located above the space between said inclining and second conveying means.

7. The apparatus of claim 6 wherein said second conveying means is provided with a driving means to move said second conveying means at a speed greater than said certain speed.

8. An improved apparatus for coating sheet-like items of flexible material under a substantially continuous curtain of coating substance, said apparatus comprising: a first endless conveyor for supporting and propelling items of flexible material at a certain speed in a given plane and direction with said items spread to expose the surface to be coated upwardly; an upwardly inclined plate at the end of said first conveyor, in said direction, said plate extending substantially thewidth of said conveyor and being adjustable angularly with respect to the plane of said conveyor so as to project items discharged from said conveyor in an upwardly inclined attitude; a plurality of axially aligned transfer rolls spaced in said direction from the edge of said plate, the surface of said rolls being at a level below the end of said inclined plate so as to receive and support items projecting from said plate after spanning the space therebetween; a second-endless conveyor adjacent said transfer rolls, said conveyor adapted to receive said items from said transfer rolls and move them further in said direction; and a coating head positioned above said space between said plate and said transfer rolls, whereby a substantially continuous curtain of coating substance falls therebetween.

9. The apparatus of claim 8, including drive means connected to said first endless conveyor and said transfer rolls, said drive means turning the surface of said rolls in said given direction at a speed greater than said certain speed.

References Cited in the file of this patent UNITED STATES PATENTS 593,896 Johnson Nov. 16, 1897 790,023 Arkell May 16, 1905 1,411,249 Allhiser Apr. 4, 1922 2,790, 413 Gregory Apr. 30, 1957 2,963,002 Glaus Dec. 6, 1960 FOREIGN PATENTS 708,491 Germany June 12, 1941

Claims (1)

1. AN IMPROVED METHOD FOR COATING SHEET-LIKE ITEMS OF FLEXIBLE MATERIAL, SAID METHOD COMPRISING: PROPELLING A SINGLE THICKNESS SHEET OF FLEXIBLE MATERIAL AT A CERTAIN SPEED ALONG A SUBSTANTIALLY HORIZONTAL GIVEN PATH IN A GIVEN DIRECTION; UPWARDLY INCLINING SAID PATH SLIGHTLY AT A LOCATION ALONG SAID DIRECTION: SUPPORTING SAID SHEET FROM ITS UNDERSIDE ALONG SAID PATH AT SAID LOCATION; DISCONTINUING SUPPORT OF SAID SHEET FOR A RELATIVELY SHORT DISTANCE IN SAID DIRECTION BEYOND SAID LOCATION; RECOMMENCING SUPPORTING SAID SHEET BEYOND SAID DISTANCE, IN SAID DIRECTION; AND COATING ONLY THE UPPER SURFACE OF SAID SHEET BY FLOWING DOWNWARDLY FROM ABOVE SAID SHEET A SUBSTANTIALLY CONTINUOUS VERTICAL CURTAIN OF SUBSTANCE UPON THE UPPER SUR-

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