US2075620A - Coating apparatus - Google Patents

Description

March 30, 1937. c. M. MACKENZIE comma APPARATUS Filed Jan. 2, 1936 4 Sheets-Sheet 1 March 30, 1937. c. M. MACKENZIE COATI-NG APPARATUS 4 Sheets-Sheet 2 Filed Jan. 2, 1956 [fa/672507": Min [7, ficzckergjz'e March 30, 1937. c. M. MACKENZIE- COATING APPARATUS Filed Jan. 2, 1936 4 She'ets-Shet 3 v 4,: I [72 venjar- CqZinM/Vac March 30, 1937, c. M. MACKENZIE 1 2,075,620

COATING APPARATUS Filed Jan. 2, 1936 4 Sheets-Sheet 4 Ali/6712. 07" 50 572 MMQ ceig ie awn... so, 1931 UNITED STATES 2,075,620 COATING APPARATUS Colin Malcolm Mackenzie, Wabash, Ind., assignor to Container Corporation of America, Chicago, 111., a corporation of Delaware Application January 2, 1936. Serial No. 52,128

scams. 91-51) This invention relates'to a machine for applying liquid coatings to sheet material such as paperboard, and more particularly relates to a 10 kenzie by which a smooth coating of lacquer may lugs to sheet material carried on a sheet carrymachine in which the coating is applied to separate sheets.

This invention typifies one form of a machine for carrying out the ,Paper coating process" disclosed in U. S. Patent October 1, 1935 to C. E. Fawkes No. 2,016,085 granted and C. M. Macbe applied to a sheet of paperboard.

One object of this invention is to provide an efficient form of machine for applying liquid coating cylinder by means of a rotating applicator roll. Another object of the invention is to provide an arrangement for maintaining the applicator roll out of contact with the face of the sheet carrying cylinder while no sheet is present thereon.

Another object of the invention is to provide means for causing the applicator roll to move into contact with the sheet carrying cylinder when a sheet is to be coated and move out of contact therewith after the sheet has been coated, and

- remain so out of contact until another sheet is to becoated.

A further object of this invention is to provide adjustable operating means which are adapted to vary the periods of time during which the applicator roll is maintained out of contact with the sheet carrying cylinder so as to adapt the machine for effectively applying acoa-ting over various lengths of sheets fed to the machine.

A further object of the invention is to provide an arrangement of applicator roll and doctor roll in which the doctor roll is arranged to be intermittently rotated, while the applicator roll is out of contact with the sheet carrying cylinder, and be stationary while a sheet is being coated.

A further object is to provide means for regulating the distance between the surface of the applicatorroll and the surface of the doctor roll.

A still further object is to provide means for regulating the differential surface speed between the applicator roll and the sheet carrying cylinder.

These and other objects not specifically enumerated, though contemplated by this invention, will readily appear to those skilled in the art as the description proceeds. 4

For a better understanding of the invention, reference may be made to the accompanying drawings in which:

Fig-1 is a diagrammatic view of the essential elements of the machine; h

Fig. 2 is a diagrammatic view showing one arrangement of driving mechanism for the machine; 1

Fig. 3 is a vertical sectional view taken alon line 3-4 of Fig. 4; v

Fig. 4 is a horizontal sectional view taken along the line 4-4 of Fig. 3;

Fig. 5 is a horizontal sectional view taken substantially on line 5-5 of Fig. 3;

Fig. 6 is a fragmentary side elevation of the machine asit appears when viewed from the left side of Fig. 4.

In general, this invention pertains to a machine for applying liquid coatings to sheet material which comprises a sheet carrying cylinder operating in conjunction with an applicator roll and plicator roll is out of contact with the sheet carrying cylinder, the doctor roll being capable of adjustment toward and from the applicator roll.

Referring more particularly to Fig. l of the drawings illustrating the preferred mechanism in diagrammatic form, the individual sheets l0, 10 are arranged in a pile on a suitable support ll so as to permit them to be fed singly to a sheet carrying cylinder l2 which rotates with a sheet thereon to bring the sheet into contact with an applicator roll l3 which delivers to the sheet a film of coating liquid supplied from a tank It. A doctor roll I5 is arranged to regulate the thickness of the coating liquid applied to the sheet. Upon discharge of the sheet from the sheet carrying cylinder it is delivered to a conveying means it which preferably carries it to a drying oven,

not shown.

Referring to Figs. 3 to 6, inclusive, the various operating parts of the machine are shown as mounted on a suitable frame which comprises two main portions 2| and 22 spaced laterally from each other and arranged to support the ends of the various shafts. as hereinafter described.

The sheet carrying cylinder'iZ is mounted on a shaft 23 which is iournalled at its ends in suitable bearings 24, 2 formed in or otherwise suitably supported on the frame members 2! and 22, as shown at Figs. 3 and 6. For the purpose of driving the sheet carrying cylinder l2 a gear 25 is preferably employed which is keyed to the shaft 23 and meshed with a gear 26 on a jack shaft 21 which also has keyed thereon a sprocket wheel 28 driven from a motor 29 by means of a suitable sprocket chain 30 engaging a sprocket 3| fixed on the motor shaft 32. The applicator roll I3 is driven in the present instance by means of a sprocket wheel 33 which is also keyed to the jack shaft 21, a sprocket chain 34 connecting the sprocket wheel 33 to an intake sprocket wheel 35 which is keyed to a shaft 36 on an ordinary variable speed transmission 31. A sprocket wheel 38 is keyed to an output shaft 39 on the variable speed transmission 37 and is connected by means of a sprocket chain 40 to a sprocket wheel 4| which is keyed to the shaft 42 on which the applicator roll I3 is mounted.

Through the arrangement just described and shown diagrammatically at Fig. 2, the sheet carrying cylinder I2 is rotatedin the direction indicated by the arrow, and the applicator roll I3 is rotated in a direction as indicated by the arrow, although the direction of rotation of the applicator roll could well be changed if desired.

It is particularly desirable to drive the applicator roll I 3 by means of a variable speed'transmission or similar device as described since, by using such a gear the speed of the applicator roll can be regulated at will so that any desired differential in speed can be maintained between the applicator roll and the sheet carrying cylinder I2. If desired, however, the applicator roll could be driven directly from the jack shaft 21 by suitable gearing.

In the coating operation the sheets II) are 0 fed to the sheet carrying cylinder |2 from a stack as shown at Fig. 1, that is the sheets I0 are in dividually fed down on to the top of the sheet carrying cylinder l2 where the foremost edge of the sheet is gripped by suitable grippers carried on the cylinder and such sheet is carried, by the rotation of the cylinder across the surface of the applicator roll l3 where a coating composition is applied to the surface of the sheet, the coating composition being maintained in a tank l4. After the sheet lll'has crossed the applicator roll I3 it is carried to the top of the cylinder l2 where it is released and carried away to be dried on an endless conveying means I6. While the sheet I0 is being thus released, another sheet cannot be fed to the cylinder l2 and such cylinder makes one complete revolution after the discharge of the sheet before another sheet is fed thereon.

In order to prevent a coating from being applied to the surface of the cylinder I2 which supports a sheet as it rotates past the applicator roll |3 with no sheet thereon, it is necessary to cause the applicator roll I 3 to move out of contact with the cylinder 2 and remain so out of contact until another sheet has been applied to such cylinder and such sheet has advanced to the point where it starts across the surface of the applicator roll. For this purpose, the ends of the shaft 42 upon which the applicator roll I3 is mounted are each journalled in eccentric bushings 43, 43 which are disposed within slide bearings 44, 44 which in the present instance are slidably mounted in guide frame members 45, 45, thereby permitting bodily movement of the applicator roll toward and from the cylinder I2. The guide frame members being screwed to the frame 2| and 22 by means of screws 46, 46.

In order to regulate the thickness of and smooth the coating liquid applied to the applicator roll a doctoring means is desirable. In the present instance such doctoring means is shown in the form of a doctor roll l5 which contacts the surface of the applicator roll l3, as shown at Fig. 1, such doctor roll being mounted on a shaft which is journalled at each of its ends in eccentric bushings 5|, 5|, which are, in turn, journalled in slide bearings 52, 52, the slide bearings being slidably mounted in the guide frame member 45, in cooperative relationship with the slide bearings 44 for a purpose to be later described.

The distance between the applicator roll l3 and the doctor roll I5 is maintained fixed at all times, subject to adjustment of the eccentric bushings, by means of links 56, 56 which are connected to the ends of the shafts 42 and 50 as shown at Figs. 4 and 5.

Inasmuch as different operating conditions sometimes require different settings between the applicator roll l3 and the doctor roll l5 it is desirable to provide means for adjustment between such rolls, this adjustment is provided for, in the present instance by employing the eccentric bushings 5|, 5| which are adapted to be rotated and thus vary the distance between the rolls. For this purpose the eccentric bushings 5|, 5| have gear teeth 53, 53 cut in their outside rim, such gear teeth meshing with the gear segments 54, 54 which are fixedly mounted at each end of a shaft 55 which is journalled in brackets 54a on the frames 2| and 22, as shown at Figs. 5 and 6. In order to provide for easy movement of the gear segments 54 a lever arm 55a is attached to the gear segment 54 which is adjacent the frame portion 2|. By moving the lever arm 55a the gear segments 54 cause the eccentric bushings 5| to rotate and thereby move the doctor roll I5 toward or from the surface of the applicator roll I 3, as desired.

The gear segments 54 and the gear teeth 53 are each of such a length that they do not become disengaged by the movement of the doctor roll I 5, referred to above.

Means are provided to cause "the applicator roll to move out of contact with the sheet carrying cylinder after a sheet has been coated and remain so out of contact until another is in position to be coated. These means comprise link members which are pivotally connected at one of their ends to the shaft 42 adjacent each end of the applicator roll, as shown in Figs. 4 and 5 and connected at their other ends to bell crank levers 6| by means of bolts 62. The bell crank levers 6| are fulcrumed on the frame members 2| and 22 by means of pins or bolts 63. A rod 64 is threaded into the end of a member 65 and is connected to a yoke on the bottom end of each of the bell crank levers 6|, by means of a pin 66 as shown in Figs. 3 and 5. The other ends of the rods 64 are slidably positioned within guide blocks 61 which are, in the present instance formed on the frames 2| and 22, as shown at Figs. 4 and 5. Pressure springs Ill encircle the rods 64 between the guide blocks 61 and locknuts H, the pressure of the spring being capable of variation by adjustments of the locknuts II. Cam follower rolls 12 are rotatably mounted in a yoke on each bell crank lever 6| on pins 13 as shown at Figs. 3, 4, and 5, the periferal surface of these rollers extending beyond the shoulders of the yokes. Due to the springs ID, a pressure is maintained against each end of the bell crank levers 6| which is transferred through the link 66 to the applicator roll shaft 42 and causes the applicator roll l3 to be constantly urged in means of a sprocket chain the direction of and held in contact with the sheet carrying cylinder l2.

Means are provided for intermittently forcing the applicator roll out of contact with the sheet carrying cylinder at stated intervals in the machine operation, such means comprising compound cams 14 which rotate against each of the cam follower rollers 12 on the bell crank levers 8|. The earns 14, in the present instance are formed of two flat cam surfaces 18 and 18 which contact each other, the cam surface 18 having arcuate slots 11, 11 formed therein, the cam 16 having bolts 18 fixed thereto which extend through the arcuate slots 11. By adjusting the two cam surfaces with relation to each other it is possible to create a high point thereon which. may be lengthened or shortened circumferentially. Nuts 18 are provided on the ends of the bolts and, when tightened, cause the cam surfaces to remain in fixed relation with each other. The cams 14 are preferably mounted on a shaft 88 in such a way that one of the cam surfaces',-

either 18 or 16 is capable of movement inde-. pendent of the shaft. The shaft 88 is suitably journalled adjacent its ends in the frame members 2| and 22. The shaft 88, together with the cams 14 are driven, as shown at Fig. 2, by means of a sprocket wheel 8| keyed to the end'of the shaft 88 which is journalled in theframe member 22. The sprocket wheel 8| is connected by 82 to a sprocket wheel 88 which is mounted on a shaft 84 journalled in the frame 22. A gear 88 is also mounted on the shaft 84 and 85 meshes with a gear 88 which is keyed to the jack shaft 21, the jack shaft 21 being driven by the motor 28, as heretofore described. Through the gears and sprocket wheels just described, the cams 14 are driven to rotate in the direction of the arrow, as shown at Fig. 3. As the high portions of the cams 14 come in contact with the cam follower rollers 12, a pressure is exerted against such cam follower rollers causing the springs 18 to be'compressed and the bell crank levers to rock on their fulcrums 88 in such a way that the applicator roll i8 is drawn out of contact with the sheet carrying cylinder 12' through the link 88, and remains so as long as the high surface of the cams 14 contact the rollers 12, as soon as such high surface passes the rollers 12 the spring 18 forces the applicator roll I! back into contact with the cylinder 12. 4

As heretofore stated, the ends of the shaft 42, on which the applicator roll i8 is mounted are journalled in eccentric bushings 43 which are mounted in the slide bearings 44. As thecams.

14 or the springs" rock the bell crank levers 8| the slide bearings permit the applicator roll the'links 56 also moves I! to move back and forth. The slide bearings 44 are preferably held in place within the guide frame members '45 by means of projections 81, 81 formed on the guide frame members 45,,such projections 81 fitting within notches 88 formed in said slide bearings, as shown in Fig. 5. As the its slide bearings the is attached by means of in its slide bearings 52,: the relationship between such rolls thus remaining constant at all times.

As previously stated, the shaft 42 is journalled in eccentric bushings 48, these eccentric bushdoctor roll to which it ings being capable of adjustment to compensate for changes in diameter of the applicator roll, that is, if a new applicator. roll is put into the machine which has a slightly greater or lesser 'tently, the coating liquid which is placed surface by the doctoring operation tends to bethe coating liquid in in which a wheel or a of the shaft 88 which atone endto diameter than the previous applicator roll, such "difference in diameter can be compensated for by an adjustment of the eccentric bushings 43. In order to hold the eccentric bushings 43 in any desired position, a lock washer 48:: may be provided which engages such eccentric bushings and holds them in fixed position, such lock washer being held in position by means of a screw 43b screwed into the guide frame 45, all as shown at Fig. 5. If desired, eccentric bushings 82a may be provided around the bolts 82 which connect the bell crank levers 8| to the links 88. The eccentric bushings 82a serving to admit of further adjustment of the applicator roll l8.

In order to facilitate the removal of the applicator roll'from the machine in the event a new applicator roll is to be substituted, a removable guide frame bracket 88may be provided which is adapted to be held in place on the guide frame member by means of screws 88.

The doctor roll 15 may be, if desired, geared to be continuously driven from the shaft 42 by means of suitable intermeshing gears or, as in the present instance, it may be arranged to be driven intermittently or periodically. By driving the doctor roll intermittently or periodically; it is meant that it is so timed with regard to the sheet carrying cylinder that at the time a sheet the sheet leaves the sheet leaves the surface of the applicator roll, the doctor roll is caused to make a turn so that a clean doctoring surface will be presented to the face of the applicator roll in preparation for the coating of the next sheet. It is desirable to have the doctor roll partially immersed in the coating liquid, as shown at Fig. 1, and to either continuously rotate the doctor roll or intermittently rotate it because of the fact that the coating liquid which is doctored from the. applicator by the doctor roll tends to harden on the surface of such doctor roll if it remains stationary, and, when it so hardens, it causes an uneven doctoring effect. By rotating the doctor roll .either constantly or intermiton its it comes in contact with the tank l4 and a uniform doctoring effect is always obtained.

One method of adapting the doctor roll for intermittent rotation is shown at Flgs..4 and 6 disc 8| is keyed to the end extends through the frame 2| and a connecting rod 82 is pivotally connected the surface of the disc 8| by means of a wrist pin 83 and is pivotally connected at its other end to an arm 84 by means of a wrist pin 85,'said arm 84 being pivotally mounted on the doctor roll shaft which extends through the frame 2|. A ratchet wheel 88 is keyed to the doctor roll shaft 50 and is, in the present instance, disposed adjacent the inner surface of the'arm 84, as shown at Fig. 4. A pawl 81 is affixed to the inner surface of the arm 84 in such a manner as to engage the teeth of the ratchet wheel 86, such pawl tact with the ratchetwheel by means of a spring 88. As the wheel 8| is rotated the arm 84 is moved back and forth causing the ratchet wheel 86 to be intermittently rotated through its engagement with the pawl 81.

' By proper adjustment of the operating parts the periodic turning of the doctor roll l5 can be come dissolved when properly timed with relation to the sheet being the surface of the applicator;

roll 13, the doctor roll is stationary, and after partial being held in constant concoated, so that the doctor roll turns at a time when the applicator. roll is out of contact with the sheet carrying cylinder.

As heretofore stated, one of the gear segments 54 has an arm 55a thereon which enables the gear segments 54 to be moved, such movement of the gear segments 54 causing the eccentric bushings 5| on the doctor roll shaft to rotate and thereby change the distance between the surface of the doctor roll [5 and the applicator roll l3. In order to keep the distance between the doctor roll l5 and the applicator roll l3 constant, a plate 99 may be mounted on the frame II, as shown at Fig. 5, such plate having holes therein which are adapted to engage a pin I00 on the arm a and hold it in fixed relation thereto at any desired setting.

In order to facilitate the removal of the doctor roll from the machine in the event it is found necessary to remove such doctor roll, removable guide frame brackets I 0| are provided which may be screwed to the guide frame member 45, as by means of screws I02, shown at Fig. 3.

In the operation of the machine of the present invention, the cams 14 are so adjusted with rela tion to the size of the sheet which is to be coated, and their period of rotation is so timed with the rotation of the sheet carrying cylinder [2, that, as soon as the sheet is coated and moves out of contact with the surface of the applicator roll, the high surface of the cams contact the cam follower rollers I2 and force the applicator roll out of contact with the sheet carrying cylinder, the applicator roll being so held out of contact until a new sheet starts across the surface of the applicator roll, at which time the low surface of the cams begins to turn past the cam follower rollers and the pressure spring 10 forces the applicator roll back into contact with the sheet.

When coating liquids are being applied which, in order to secure a smooth application, require a differential periferal speed between the applicator roll and the sheet carrying cylinder, as more particularly defined in the above referred to United States Patent No. 2,001,685, the variable speed transmission 21 can be readily adjusted so that the desired differential speed relation can be obtained.

From the foregoing, it will be manifest that there has been provided a simple and effective machine which is capable of readily applying various types of liquid coatings to individual sheets, and which is capable of adjustment to meet varying sets of operating conditions.

While the present description sets forth a preferred embodiment of the invention, certain changes and variations can be made without departing from the spirit of the invention and it is therefore desired that the present embodiment shall be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim: 1. An apparatus for applying a liquid coatin composition to sheets comprising, in combination, a sheet carrying cylinder, means for rotating said cylinder, a rotatable applicator roll, a normally stationary doctor roll for the applicator roll, means for mounting said applicator roll for bodily movement toward and from the face of the sheet carrying cylinder, pressure means arranged to constantly urge the applicator roll bodily in the direction of and into contact with the sheet carrying cylinder, and means arranged to pe- V riodically move the applicator roll bodily away from and out of contact with the sheet carrying cylinder, and means for imparting a periodic motion to said doctor roll while said applicator roll is out of contact with said sheet carrying cylinder.

2. An apparatus for applying a liquid coating composition to sheets comprising, in combination, a sheet carrying cylinder, means for rotating said cylinder, a rotatable shaft, an applicator roll mounted on said shaft and contacting said sheet carrying cylinder, each end of said applicator roll shaft being mounted in slidable hearings to allow the applicator roll to move toward and from the sheet carrying cylinder, a bell crank lever, a link connecting one end of said bell crank lever to said applicator roll shaft, pressure means connected to the other end of said bell crank lever to normally maintain said applicator roll in contact with said sheet carrying cylinder, and a rotatable cam adapted to operate against said bell crank lever and intermittently force said applicator roll out of contact with said sheet carrying cylinder. I

3. An apparatus for applying a liquid coating composition to sheets, comprising, in combination, a sheet carrying cylinder, means for rotating said cylinder, a rotatable shaft, an applicator roll mounted on said shaft and contacting said sheetcarrying cylinder, each end of said applicator roll shaft being mounted in slidable bearings to allow the applicator roll to move toward and from the sheet carrying cylinder, variable speed driving mechanism for rotating said applicator roll at a critical differential lineal speed ratio to that of said sheet carrying cylinder, a bell crank lever, a link connecting one end of said bell crank lever to said applicator roll shaft, pressure means connected to the other end of said bell crank lever to normally maintain said applicator roll in contact with said sheet carrying cylinder, and a rotatable cam adapted to operate against said bell crank lever and intermittently force said applicator roll out of contact with said sheet carrying cylinder.

4. An apparatus for applying a liquid coating composition to sheets, comprising, in combination, a sheet carrying cylinder, means for rotating said cylinder, a'rotatable shaft, an applicator roll mounted on said shaft and. contacting said sheet carrying cylinder, a doctor roll for the applicator roll, each end of said applicator roll shaft being mounted in slidable bearings to allow the applicator roll to move toward and away from the sheet carrying cylinder, a bell crank lever, a link connecting one end of said bell crank lever to said applicator roll shaft, pressure means connected to the other end of said bell crank lever to normally maintain said applicator roll in contact with said sheet carrying cylinder, a rotatable cam adapted to contact said bell crank lever and intermittently force said applicator roll out of contact with said sheet carrying cylinder, and a pawl and ratchet mechanism adapted to impart a step by step motion to said doctor roll while said applicator roll is out of contact with said cylinder.

5. In an apparatus for applying a liquid coating to sheets wherein a base frame is provided on which is mounted a sheet carrying cylinder and an applicator roll having a shaft journaled in bearings movably mounted on the frame and means for moving the applicator r011 intermittently toward and from the sheet carrying cylinder in proper timed relation to coat a 'sheet carried thereon, the combination with said appli- 5 enter roll or a doctor roll having a shaft Journaled in bearings mounted for alidable movement on the frame, and link mechanisms connecting the shafts of the doctor roll and applicator roli' to maintain the two rolls in constant relation irrespective of the intermittent movement of said applicator r011.

COLIN MALCOLM MACKENZIE.

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