US2981226A - Roller coater machine - Google Patents

Description

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5 Sheets-Sheet 1 Filed April 27, 1960 JNVENTOR. EF/YaJZ ZTA/ur April 25, 1961 E. E. MURRAY ROLLER COATER MACHINE 5 Sheets-Sheet 2 Filed April 27, 1960 warn: nnggagu INVENTOR. .27/7652" .Z'Y ay.

April 25, 1961 E. E. MURRAY ROLLER COATER MACHINE 5 Sheets-Sheet 3 Filed April 27, 1960 April 25, 1961 E. E. MURRAY 2,981,225

ROLLER COATER MACHINE Filed April 27, 1960 5 Sheets-Sheet 4 I /NVENTOR 777662 ZT Vq/vz April 25, 1961 E. E. MURRAY ROLLER COATER MACHINE 5 Sheets-Sheet 5 Filed April 27, 1960 United States Patent F ROLLER COATER MACHINE Ernest E. Murray, 2545 W. Maple, Birmingham, Mich. Filed Apr. 21, 1960, Ser. No. 24,919

8 Claims. Cl. 118-227) This invention relates generally to apparatus for applying a thin layer of a liquid material to sheets to be coated, and more particularly to an improved roller coater machine.

Roller coater apparatus is used for applying a thin layer of a coating material to sheets to be coated, for example, coating metal sheets with materials such as drawing compounds which lubricate the sheet surfaces during forming of the sheet in a die. The coating, which is in a liquid form, accumulates in a pool in the roller coater machine and a rotatable applicator roll positioned so that it constitutes one side of the pool picks up the coating material from the pool and applies it to the sheet stock. Where both sides of the sheet are to be coated, two pools and two applicator rolls are used. Difliculty has been encountered with some of the drawing compounds and other liquid coating materials because of the vigorous agitation of the liquid which takes place in the pool. These compounds have a tendency to foam under the action of the rotating applicator roll which also acts to work air into the pool, and a foamed and aerated compound cannot be uniformly applied because of the air therein and accurate control of the amount of coating material being applied is lost. It has been found that this difliculty can be overcome by preventing the pool of liquid coating material from reaching a large enough size to be .vigorously agitated. In other words, when using such a coating material, the size of the pool is reduced to an extent such that the coating material does not remain in the pool long enough to be foamed. The pool is maintained of a minimum size just large enough to insure a continuous application of coating material to the rotating applicator roll passing through the pool.

.When using a particular coating material, the size of the pool is adjusted by the machine operator, after observing the characteristics of the pool and the quality of the coating, to obtain the desired coating results and it is an object of this invention, therefore, to provide an improved roller coater machine which has structure for adjusting the sizes of the pools of liquid coating material therein. This is accomplished by forming the doctor member associated with each applicator roll with an overflow edge so that the pool of coating material between the doctor member and the applicator roll cannot exceed a predetermined size because excess material will flow out of the pool across the edge. The doctor member is adjustably mounted in the machine so that the vertical position of the overflow edge can be adjusted, and by forming the doctor member of a cylindrical shape this adjustment can be readily accomplished by rotatably mounting the doctor, and the overflow edge is formed by providing the doctor with a longitudinally extending surface groove or channel.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims and the accompanying drawing in which:

Figure 1 is a fragmentary perspective view of the roller coater machine of this invention;

Figure 2 is an enlarged transverse sectional view of the machine of this invention, as seen along the line 2-2 in Fig. 1;

Figure 3 is a transverse sectional view of the machine of this invention looking substantially along the line 3-3 in Fig. 1;

Figure 4 is a plan view of the top portion of the ma chine of this invention;

Figure 5 is a plan view of the bottom portion of the machine of this invention;

Figure 6 is a fragmentary sectional view looking along the line 66 in Fig. 5; and

Figure 7 is a fragmentary sectional view of an applicator roll and its doctor roll in a machine of this inven-' tion, illustrating the angular bight formed between the rolls, and showing the pool of liquid coating material contained in the bight.

With reference to the drawing, the roller coater machine of this invention, indicated generally at 10, is illustrated in Fig. 1 as consisting of an-upper frame unit 12 mounted on a lower frame unit 14 which is in turn mounted on a supporting structure 16 which functions to position the frame units 12 and 14 at a desired height. The lower frame 14, which includes hollow side wall sections 14a connected by tie rods 14b, supports a pair of horizontal sheet supporting roller units 18 and 20 which are adapted to support a metal sheet, indicated generally at 22 in Fig. 3, during travel of the sheet 22 through the machine 10 for coating of one or both sides of the sheet. The unit 18 consists of a shaft 26 having disks 27 fixed at spaced positions thereon and the unit 20 consists of a shaft 23 having disks 25 fixed at spaced positions thereon. The upper frame 12, which includes hollow side wall sections 12a connected by tie rods 12b, carries a pair of depending bearings 24 which are rotatably supported on the shaft 26 in the roller unit 18. As a result, the upper frame unit 12 is hingedly supported on the lower frame 14 so that it can be swung upwardly about shaft 26 to provide access to the moving parts mounted on the lower frame 14.

The upper frame 12 supports a horizontal applicator roll 28 (Fig. 3) that is fixed on a horizontal shaft 30 mounted on the frame end walls 12a. The roller 28 is of a resilient material such as rubber and is positioned adjacent a metal doctor roll 32 which is mounted on a shaft 34 that is slightly above and to one side of the shaft 30. A feed trough 36 having discharge openings 44 for coating material is disposed above the applicator roll 28 and is mounted at its ends on arms 38 that are secured by releasable clamp supports 40 to the shaft 34. The trough is provided at its ends with inlet pipe connections 42 which are connected by flexible hoses 45 or the like to suitable pumping apparatus which pumps the liquid coating material to be applied with the ma chine 10 through the inlet pipes 42 into the trough 36 for flow out of the trough through the outlet openings 44 therein onto the top side of the applicator roll 28. As best appears in Figs. 3 and 7, the doctor roll 32 and the applicator roll 28 are positioned so as to form therebetween a cavity or angular bight 46 and, as will more clearly appear hereinafter, the liquid coating material applied along the length of the applicator roll28 from the trough openings 44, accumulates in the bight 46.

The lower frame 14 likewise carries an applicator roll 50 which is fixed on a shaft 52 mounted at its ends on the side walls 14a. The roll 50 is positioned in vertical alignment with the applicator roll 28 and is in a closely spaced relation therewith so that the rolls will engage opposite sides of the sheet 22 during its travel through as viewed in Fig. 6.

the machine. The applicator roll 50 has a doctor roll 54 adjacent thereto which is mounted on a shaft 56 that is below and to one side of the shaft 52. Therolls Siland 54 cooperate to form therebetween an angular'bight 58 which corresponds to the bight 46 described above.

A supply trough 68 is positioned above the roll 58 and is provided with outlet openings 62 disposed so that liquid coating material flowing through the openings 62 is applied along the length of the applicator roll 58. The trough 68 is supported at its ends on arms '64 which are secured by clamp units 66 to the shaft 56 for the roll 5%.

Inlet pipe connection 67 at-the ends of the trough 68 areconnected to suitable pumping apparatus which provides the trough 68 with a continuous Supply of the coating material which it is desired to use-in themaohine it).

In the use of the machine 18, a continuous sheet 22 from a roll of sheet metal is passed'through the machine in the direction of the arrow 78 in Fig.3. The sheet 22 is supported on the entrance'roller unit 18, passes between the applicator rolls 2?; and 58, and is supported on the exit roller unit 28. The spacing between the rolls 28 and 58 is readily adjusted by manipulating a pair of threaded studs 72 carried by the upper frame 12 and supported on the lower frame 14 at a position adjacent the sheet support roller unit 28. When the studs 72 are rotated so that they are threaded downwardly relative to the frame 12, the upper frame 12 is swung upwardly aboutthe shaft 26 so as to increase the spacing between the applicator rolls 28 and 5t) and when the studs 72 are rotated so that they are moved upwardly relative to the frame 12, the upper frame 12 is permitted to move downwardly toward the lower frame 14.

The support structure 16 carries a drive shaft 74 which is connected to any suitable source of driving power so that it drives a sprocket 76 which is positioned in vertical alignment with a sprocket 78 on one end of the shaft 26 for the roller unit 18. A drive chain 80 extends about the, sprockets 76 and 78 so that on rotation of the shaft 74 in a clockwise direction as viewed in Fig. 6, the drive roller 18 is driven in a direction to advance the sheet 22 through the machine 19 in the direction of the arrow 78. A gear 82 secured to the shaft 26 at a position adjacent the sprocket 78 meshes with a similar gear-84 carried on one end of a shaft 86 which is supported on the upper frame end walls 12m. A sprocket 88 on the opposite end of the shaft 86 is positioned in a vertical plane which passes through a sprocket 98 mounted on the shaft for the applicator roll 28, A drive chain 92 trained about the sprockets 88 and 90 and-an idler sprocket 94 mounted on the frame 12 provides for driving of the applicator roll 28 in a counterclockwise direction as viewed in Fig. 3 in response to rotation of the power shaft 74 in a clockwise direction as viewed in Fig. 6.

The shaft 26 for the roller unit 18 carries a sprocket 98 on the end thereofopposite the gear 82 and the sprocket 98 is positioned in the vertical plane of; a sprocket 100 on the shaft 52 for the lower applicator roll 50. A drive chain 102 trained about the sprockets 98 and 100 and an idler sprocket 101 on the lower frame 14 provides for driving of the lower applicator roll 50 in a clockwise direction as viewed in Fig. 3 in response to rotation of the power shaft 74 in a clockwise direction The gears 82 and 84and the sprockets 88, 90, 98 and 100 are. proportioned so that the applicator rolls 28. and 50 rotate at the, same speed and the peripheral speed of the rolls 28 and 50. corresponds to the peripheral speed of the roller unit disks 27 so that there is no slippage between any of the rollers and the sheet 22. The exit roller unit 20 .is driven by a drive chain 104 which is trained about a sprocket 106 on the shaft 52and a sprocket 108 onthe shaft 23 which rotates at the same speed; asthe shaft; 26.

The spacing between the applicator roll 28 and its doctor roll 32 determines the. thickness of .the,coating applied to the top side of the sheet 22 since this spacing assists" determines the amount of coating liquid that adheres to the roll 28 and is transferred to the sheet 22. The thickness of the coating applied to the bottom side of the sheet 22 is determined by the spacing between the applicator roll 50 and its doctor roll 54. To provide for adjustment of this thickness, the doctor rolls 32 and 54 are adjustably mounted on their frames 12 and 14, respectively. The shaft support 34 for the doctor roll 32 is mounted at its ends in substantially rectangular slide blocks 110, each of which is slidably mounted on a pair of vertically spaced guide members 112 carried on the frame sidewalls 12a. T he shaft 34 is rotatably mounted in its slide blocks .110 and a set screw 114 is provided in one or both of the slide blocks for advancement into engagement with the shaft 34 for holding the shaft 34 in a rotated adjusted position in the slide blocks 1 10. Each slide block 110 is connected to one end of a horizontal rod 116 which is provided at its opposite-ends with threads 118 and is threaded into a block 120 carried by the frame 12. The rod 116 carries aworm wheel 122 which meshes with a worm 124 mounted on ashaft 126 carried by and extending transversely of the frame squared ends 130. On application of a wrench to the squared ends 130, the shaft 126 is readily rotated to provide for rotation of the-worm wheels 122 to in turn move thethreaded rods 1 16 in a horizontal direction on the frame 12 to thereby move the slide blocks 110 horizontally on their guide members 112. This movement of the slide blocks lltl is operable to either advance the doctor roll 32 toward the applicator roll 28 or move it in the direction away from the applicator roll 28, depending on the direction of rotation of shaft 126, to obtain the desired spacing between the rolls 28 and 32 for theparticular coating material to be applied in the machine 10;

The lower doctor roll 54 likewise has its shaft 56 rotatably supported at its ends in guide blocks 132 which are substantially rectangular and which are slidably supported on vertically spaced guide members 134 carried by the frame .side walls 14a. One .or more set screws 136 in either or both of theguide blocks 132 are operable to, hold the shaft 56in adjusted rotated positions in guide, blocks 132. The blocks 132 are connected to horizontal rodsv 138 which are threaded in blocks 140 car- Tied by the frame 14 and carry worm wheels 142 which mesh with worms 144 and are carried in gear housings v14.6 rnounted on the frame 14. .A shaft 148 carries the worms I44 and is provided'with squared ends 150 adapted to; receive a suitable wrench which is operable to rotate the shaft 148 and move the slide blocks 132 in the guidefmembers 134 to, adjust the position of the doctor roll 54 relative to theapplicator roll .50.

As shown in Fig, 3, the rotating applicator roll 28 forms one side of the angular bight 46 in which the liquid coating material from the trough 36 accumulatesand the rotating applicator roll 50 similarly forms one side of the angular bight 58 in which liquid'coating material from the trough 60 accumulates. The liquid coating material from the. trough 36 falls onto the roll 28 and travels on the roll into the bight 46 where the major portion of the liquid is, wiped off the; roll 28 by the doctor roll 32 so that a pool of liquid accumulates in the bight 46.

The continuous movement of the applicator roll 28 along one .side of the pool 165 causes a movement of the adjacent portions of liquid in the pool along with the roll 28 so that a length of the roll 28 corresponding to the length of the pool 165 is covered with liquid. Since only a thin layer of liquid is able to pass the doctor 32, the major: part of the'liquid dragged along by the roll 28is. deflected away-from the roll 28 by the doctor 32. As a result of this movement-of'liquidin thepool 165, some coating materials tend to boil up and foam strip 22 since the air bubbles formed in the coating ma- T terial cause an uneven and non-uniform application of the coating material to the sheet 22. It has been found that if the size of the pools of coating material in the bights 46 and 58 is small, the agitating effect of the rotating applicator rolls on the material in the pools is substantially reduced. 7

In the machine 10, this is accomplished by forming the doctor rolls 32 and 54 with overflow grooves or slots 152 and 154, respectively, which communicate with the angular bights 46 and 58, respectively. The groove 152 extends longitudinally of the roll 32 which is provided with end plates 156 which close the ends of the groove 152. One of the end plates 156 is formed with an opening 157 which is adjacent the lower end of groove 152 and is connected to a drain pipe 159. Coating material in the groove 152 will flow out of the doctor roll 32 through the drain pipe 159 which returns it to either a container or the reservoir for the pump which supplies the trough 36.

The doctor roll 54 is likewise provided with end plates 162 which close the ends of the groove 154. One of the end plates 162 is provided with an opening 170 which communicates with a drain pipe 178 which returns the fluid in the roll 54 to either a container or the reservoir for the pump which supplies the trough 60.

The doctor roll 32 has a portion 172 located at the upper end of the groove 156 which constitutes an overflow edge and is positioned so that it is adjacent one side of the angular bight 46. When the pool of liquid coating material in the bight 46 reaches a predetermined size, it will overflow the edge 172 and flow into the groove 152 for travel out the drain pipe 159. The doctor roll 54 has a corresponding portion 174 which constitutes an overflow edge and communicates with the angular bight 58 and when the size of the pool of coating material in the bight 58 is great enough, liquid coating material from the pool flows over the edge 174 into the groove 154 and out the outlet pipe 178. The shafts 34 and 56 for the doctor rolls 32 and 54, respectively, are

rotatably adjustable, on loosening of the set screws 114 and 136, to vary the vertical positions of the overflow edges 172 and 174 to thereby control the size of the pools of liquid coating material in the 'bights 46 and 58.

As a result, for different materials, the bights 46 and 58 may be adjusted to provide for pools of coating material therein which will give the best coating results. Any tendency of the coating material to foam is readily controlled by reducing the size of the pools.

It is very important that the surface of the doctor member 32 which is adjacent the applicator roll 28 be straight so that the film or layer of coating material which passes between the doctor member and the applicator roll is of a uniform thickness along the length of the applicator roll 28, and of course the same is true of the doctor member 54. By forming the doctor members 32 and 54 of the preferred cylindrical or roll-shape Which is illustrated, the straightness of these surfaces can be insured by turning the members on a lathe or the like. However, it is to be understood that the advantages achieved in this invention by providing the vertically adjustable overflow edges 172 and 174 on the doctor members can also be obtained by using doctor members.

which are not necessarily cylindrical, for example rectangular or of a shape in cross section resembling a segment of a cylinder, which may be more diflicult to form and assemble so as to provide the required space of uniform width between the doctor and the applicator roll. It is to be understood also that the adjustable doctor member of this invention is not limited to use in the particular type of coating apparatus illustrated in which the applicator roll contacts the pool in advance of contact with the part to be coated, but may be also used in coating apparatus of the type in which the sheet to be coated is carried on the surface of the applicator roll. Very thin sheet materials such as paper may be coated in th s manner. Asused herein, the term applicator roll includes a roll which carries the sheet to be coated when ,of liquid coating material, said doctor member having an upper overflow edge defining the upper limit of said pool, and means adjustably mounting said doctor member in said apparatus so that the position of said edge is vertically adjustable to adjust the size of said pool. 6

2. In roller coater apparatus which includes a continu ously rotatable applicator roll, and a doctor member mounted adjacent the surface of said roll to form therewith a cavity adapted to contain a pool of liquid coating material in contact with the surface of said roll in advance of its contact with a part to be coated; said doctor member having an upper overflow edge defining the upper limit of said pool, and means adjustably mounting said doctor member in said apparatus so that the position of said edge is vertically adjustable to adjust the size of said pool.

3. In roller coater apparatus which includes a frame, a pair of vertically spaced applicator rolls mounted on said frame, means on the frame for directing flat stock to be coated between said rolls, means for continuously rotating said rolls in directions such that tangentially adjacent portions thereof are movable in the same direction, a pair of doctor rolls corresponding to said applicator rolls, each of said doctor rolls being positioned adjacent its corresponding applicator roll in a position to form therewith an angular bight adapted to contain a pool of liquid coating material in contact with a surface of said applicator roll in advance of passage of said roll into coating engagement with flat stock in said machine; each of said doctor rolls having an overflow groove formed therein at a position extending longitudinally thereof at one side of the upper end of the adjacent pool so that any material supplied to the pool in excess of that required to maintain the height of said pool flows into said groove, and means adjustably supporting said doctor rolls on said frame so that the position of said grooves is adjustable to maintain said pools of predetermined sizes.

4. In roller coater apparatus which includes a continuously rotatable applicator roll, and a doctor member mounted in a closely spaced relation with the surface of said roll to form therewith an angular bight adapted to maintain a pool of liquid coating material in contact with the surface of said roll in advance of its contact with a part to be coated, said doctor member having an upper overflow edge defining the upper limit of said pool, passage means in said machine communicating with said edge for conducting coating material which overflows said edge away from said pool, and means adjustably mounting said doctor member in said machine so that it is movable toward and away from said applicator roll and so that the vertical position of said edge is adjustable to adjust the size of said pool.

5. In roller coater apparatus which includes upper and lower continuously rotatable applicator rolls adapted to engage opposite sides of sheets to be coated, and upper and lower doctor members corresponding to said rolls, each doctor member being mounted in a closely spaced relation with the surface of the corresponding roll to form therewith a cavity adapted to maintain a pool of liquid coating material in contact with the surface of said roll r r seem in advance of its contact with a sheet to be coated; each of said doctor members hav'inganupper overflow edge defining the upper limit of the adjacent pool, and means adjustably mounting said doctor members in said machine so that the vertical positions of said edges are adjustable to adjust the sizes of said pools.

6. In roller coater apparatus which includes a frame, a pair of vertically spaced applicator rolls mounted on said frame,-means on the-frame for directing sheets to be coated between said rolls, means for continuously rotating said rolls in directions such that tangentially adjacent portions thereof are movable in the same: direction at substantially the same speed, a pair of doctor rolls corresponding to said applicator rolls, each of said doctor rolls being positioned adjacent its corresponding applicator roll in a position to form therewith an angular big ht adapted to maintain a pool of liquid coating material in contact with a surface of said roll in advance of passage of said roll into coating engagement with sheets in said machine;

each of said doctor rolls having an overflow channel formed therein at a position extending longitudinally thereof at one side of the upper end of said pool so that any material supplied to the pool in excess of that required to maintain the height of said pool flows into said channel, and means rotatably supporting said doctor rolls on said frame so that the positions of said channels are adjustable to maintain said pools of predetermined sizes.

7. In roller coater apparatus which includes a frame, a pair of vertically spaced applicator rolls mounted on said frame, means on the frame for directing sheets to be coated between said rolls, means for continuously rotating said rolls in directions such that tangentially adjacent portions thereof are movable in the same direction, a pair of doctor rolls corresponding to said applicator rolls, each of said doctor rolls being positioned adjacent its corresponding applicator roll in a position to form therewith an 'ang'u'lar'big'ht adapte'a'to contain a pool "of liquid coating material in contact with a 'surface'ofs'ai'd applicator-roll in advance of passage :of said roll intoj'coating engagement with sheets to be .coated' in said rna'chine'peach of said doctor rolls having'an. overflow groove formed therein at a position extending longitudinally thereof at one side of the upper end of the adjacent pool so that any material supplied to the pool in excess of that required to'mai'ntain v the height of said pool flows intosaid groove. 10

8. In roller coater apparatus which includes a fr'ame, a rotatable applicator roll mountedon said frame, means on-the frame for directing sheets to be coated into engagement with 'said froll, means for continuously rotating said roll, and a doctor roll positioned adjacent said applicator roll in a position to formtherewith -.an angular bight adapted to contain akpool'of liquid coating material in contact with asurface of said roll in advance of passage of said roll into coating engagement with sheets in said machine; said doctor roll having an overflow groove formed therein at 'a position extending longitudinally thereof at one sideof the upper end of said pool so that any material supplied to the pool in excess of that required to maintain theheight of said pool flows into said groove, and means adjustably supporting said doctor roll on said frameso that the vertical position of said groove is adjustable to maintain said pool of a predetermined size. i 'References Cited .in the file of this patent UNITED STATES PATENTS 2,069,322 Meller et al Feb. 2, 1937 2,213,117 Blackrnore Aug. 27, 1940 2,641,220 Weber et al. vJune 9, 1953 FOREIGN PATENTS 878,011 Germany May 2-8, 1953

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