US 3418970 A
Description (OCR text may contain errors)
31, 1968 R. w. PHELPS ETAL 3,418,970
PAPER COATING APPARATUS Sheet Filed NOV. 2, 1964 INVENTORS RICHARD w. PHELPS, JAMES r. COGHILL a ROBERT E. INGISON MW? Dec. 31, 1968 R. w. PHELPS ET AL 3,418,970
PAPER COATING APPARATUS Sheet Filed Nov. 2, 1964 FIG-2 e9 INVENTORS RICHARD W. PHELPS, JAMES T. COGHILLG ROBERT E. INGISON FIG-5 ATTORNEYS i R. w. PHELPS ET A 3,418,970
PAPER COATING APPARATUS Dec. 31, 1
Sheet Filed Nov. 2, 1964 FIG-4 r ATTORNEYS Dec. 31, 1968 R w, PHELPS ET AL 3,418,970
PAPER COATING APPARATUS Filed Nov. 2, 1964 FIG- 1,37 340 7 a 7 z z 8 0 Q1 0 I80 333 m 345 I 34-5 o I33 O 12s 0 o A /50 0 I6 j 47 I59 I58 l 3 1- II T: I
zoo J r we I I56 I55 I /46 175 I68 I70 INVENTORS :2 l RICHARD W. PHELPS,
JAMES T. COGHILL 8 ROBERT E. INGISON ATTORN EYS ,1968 RW. PHELPS ET L 3,418,970
PAPER COATING APPARATUS Sheet 5 of 8 Filed Nov. 2, 1964 g I N) 5?, 5'3 8 u O O V 9 9 a,
0 INVENTORS RICHARD W. PHELPS, LL JAMES T. COGHILL &
BY ROBERT INGISON M A TORNEYS.
Dec. 31, 1968 PHELPS ET AL 3,418,970
PAPER COAT ING APPARATUS Filed Nov. 2, 1964 Sheet 6 of 8 l! (7 N) 00 Q g Y L L\ i\ gt Q L2 m 00 K Q I: INVENTORS RICHARD w. PHELPS,
BY JAMES T. coemLLa ROBERT EJNGISON ATI'ORMEYS Dec. 31, 1968 R. w. PHELPS ET AL 3,418,970
PAPER COATING APPARATUS Filed Nov. 2, 1964 Sheet 7 of 8 INVENTORS RICHARD W. PHELPS, JAMES T. COGHILL 81 ROBERT E. INGISON wwmw ATTOR N EYS Dec. 31, 1968 R. w. PHELPS ET AL 3,418,970
PAPER COATING APPARATUS Filed Nov. 2, 1964 Sheet 6 of 8 INVENTORS' RICHARD W. PHELPS, BY JAMES TI COGHILLQ ROBERT E. INGISON WMMW ATTORNEYS 3,418,?70 PAPER COATING APPARATUS Richard W. Phelps, James T. Coghill and Robert E.
Ingison, Fulton, N.Y., assignors to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Filed Nov. 2, 1964, Ser. No. 408,163 11 Claims. (Cl. 118-410) ABSTRACT OF THE DISCLOSURE Fountain coaters for coating paper with a coating liquid include a fountain trough extending transversely of a paper web and pivoted for tilting movement and being further urged by an air cylinder into coating engagement with a web support on a backing roll so that the fountain rides on a film of coating. In one embodiment, the fountain is adapted for coating in either direction of web movement and includes deckle bars for controlling the width of application of the coating. The fountains have relatively deep distribution troughs and relatively short planar upstream and downstream coating lips.
This invention relates to coating and more particularly to apparatus for coating moving webs of sheets of material.
The coater of this invention employs a controlled applicator and a blade for applying coating to the surface of a moving web of material. The applicator consists of a fountain which is positioned into coating relation with a web and is maintained in such relation by a relatively constant and controlled force. The fountain is, at all times during coating, restrained by a controlled balancing force. Thus, the fountain is, in effect, floating on a hydraulic film, and the force which is applied to the fountain is sufficient to balance the hydrodynamic pumping action which tends to push the fountain away from the web.
An important object and advantage of this invention is the provision in a coater of apparatus for applying a force on a coating fountain which urges the fountain toward the web, to achieve a balanced condition where the net forces tending to move the fountain away from the web are balanced by an opposite and controlled force tending to move the fountain toward the web.
The arrangements of this invention are accordingly one wherein a coating fountain is maintained at a relatively constant distance from a web being coated and separated from the web by a film of coating material which is being applied to the web, at any given web speed, coating viscosity, and pumping rate. The coating fountain is free to move relative to the web surface against the restraining force mentioned above with changes in web speed, in pumping rate or in coating viscosity. While the fountain is caused to float against a hydraulic head, it may move generally radially of the paper supporting roll, and this movement compensates for roll run out or for changes in web speed, while constantly applying a uniform coating to the web surface.
A blade is positioned in downward relation to the fountain for doctoring off the excess coating and returning the same to a pan for recirculation to the pumping system. This blade is preferably adjustable both in angle of incidence to the web and in spacing or dwell time in relation to the fountain. The doctor blade of this invention is preferably used without edge dams.
In one embodiment of this invention, the coater is reversible for the purpose of coating with the web moving past the fountain in either one of two directions. Accordingly, a double pass coater is provided which permits the coating of either or both sides of the web. This apparatus includes a single fountain which is movable from two nited States Patent "ice different tilted positions into a coating position, and a pair of selectively operable doctors, only one of which is used at one time depending upon the direction of web travel.
A further feature of one of the embodiments of this invention is the provision of one fluid control for bringing the fountain generally into operating position with respect to the web to be coated, and another fluid control for loading the fountain with a desired force against the web. An advantage of this arrangement is that the fountain is, in effect, floating on a film or layer of coating material, while the fountain is supported in such a manner that it may move away from the web in the event of an obstruction or an extraneous force. Such arrangement is useful in the event of a break in the web so that the coating fountain will give away from the broke.
A particular feature of the fountain applicator of this invention is that, during coating, the downstream lip of the fountain runs dry without overflow or spill. The prevention of overflow at the downstream lip provides a coating applicator which eliminates the streaking and uneven coating which would otherwise occur when the fountain downstream lip is operated in an overflowing condition. It has been found that a land surface on the edge of the trough of sufiicient dimension in the direction of web movement forming a converging nip prevents overflowing while efficiently transferring the coating material onto the moving web surface. Since the trough at the downstream lip is operated dry, not only is the coating uniformly applied, but the most eflicient use is made of the pumping equipment.
The above-described advantages provide a coater which cuts off clean when the fountain head is dropped or lowered. Foaming is reduced or eliminated, and dried coating does not build up on the fountain between the fountain and the blade to interfere with the coating action.
The above-outlined description includes many of the objects and advantages of the apparatus of the present invention, and further objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.
FIG. 1 is a view in side elevation of one embodiment of a fountain coater constructed according to this invention, with certain parts therein being shown in break away section;
FIG. 2 is a partial front elevation of the embodiment of FIG. 1, looking from right to left in FIG. 1, and showing the fountain and a portion of the backing roll with a fragment of the fountain bar and fountain tube being broken away to expose the internal details thereof;
FIG. 3 is an enlarged fragmentary transverse section of the fountain tube and bar as applied to a web during coat- 111g;
FIGS. 418 show a further embodiment of this invention in which FIG. 4 is a side elevation thereof;
FIG. 5 is a vertical section of the coater of FIG. 4 taken generally through the left hand end stand showing the control mechanism therein generally in elevation with certain parts being broken away;
FIG. 6 is a vertical section through the right hand end stand of the coater of FIG. 4, showing the control mechanism therein generally in elevation with certain parts thereof being broken away;
FIG. 7 is a front elevation of the machine looking from right to left in FIG. 4 and taken generally along the line 77 of FIG. 5, partially broken away, showing one of the doctor blade assemblies;
FIG. 8 is a transverse section through the end stands taken generally along the line 8-8 of FIG. 5 but showing the fountain assembly in front elevation, with parts thereof being broken away;
FIG. 9 is a vertical section through the fountain assembly showing the details of the fountain hanger support mechanism taken generally along the lines 99 of FIG. 8;
FIG. 10 is a partial section through the fountain assembly showing the details of the fountain clamp mechanism taken generally along the lines 1010 of FIG. 8;
FIG. 11 is an enlarged fragmentary section of the upper portion of FIG. 10 showing the details of the fountain 'bar and fountain tube assembly;
FIG. 12 is a partial section through the fountain tube showing the air bleed vent, with portions of the vent being broken away;
FIG. 13 is an isometric projection of the fountain tube, metering bar, and fountain bar in an exploded view;
FIG. 14 is a plan view, partiallyin section, of one of the deckle rod assemblies for the fountain bar;
FIG. 15 is an elevational view, partially in section, of the deckle rod assembly of FIG. 14;
FIG. 16 is a sectional end view looking generally along the lines 16-16 of FIG. 15;
FIG. 17 is an enlarged fragmentary section showing the relationship of the fountain bar and the backing roll during coating;
FIG. 18 is another enlarged fragmentary view showing a slightly modified form of fountain bar; and
FIG. 19 is a diagram illustrating the relation of the doctor blade angle to the center line of the backing roll, for controlling the dwell time between the fountain applicator and the doctor blade.
Referring to the figures of the drawings which illustrate preferred embodiments of the invention, there is shown in FIG. 1 a portion of the frame 10 of a coater. It will be understood that the coater frame may include a pair of spaced end stands which support the coating apparatus, such as the fountain end support 11 and a cross tube 12. The end stands rotatably support a backing roll 14, and suitable frame and end stand structure for his purpose is shown in the United States Patent of Jacobs et al. 3,079,889, issued Mar. 5, 1963, and assigned to the same assignee as this application.
The coater apparatus of this invention may be divided into its two basic components: a fountain assembly 15 which comprises the applicator apparatus for applying the coating to one surface of a web 16; and a doctor.
blade assembly 20 for doctoring off the excess coating applied by the fountain.
Referring first to the details of the fountain assembly 15, the fountain includes a conduit or tube 21 which, as shown in FIG. 2, extends the width of the roll 14. The tube 21 is closed or blocked at the ends thereof by suitable end plates, such as a right hand end plate 23 and a left hand end plate 24, as shown in FIG. 2. Means for applying a coating liquid to the interior of the tube may comprise a flexible inlet conduit 25, which opens centrally of the tube 21. However, it is within the scope of this invention to apply the coating material through one or both of the end plates 23 and 24.
The fountain assembly 15 further includes a fountain bar mounted on an upper surface of the tube 21 and which also extends the width of the roll 14. The bar 30 is formed with a longitudinal groove 32, which may be rectangular in section. The bar groove 32 opens into the interior of the fountain tube 21 through a series of longitudinally spaced openings 35 in the bar which open into the bottom of the groove 32. The openings 35 are in communication with similarly aligned and spaced openings 36 formed in the upper surface of tube 21 beneath the bar 30. The bar 30 and the tube 21 may be held together as a unitary assembly as by welding to the tube 21, as indicated at 37 and 38 in the enlarged fragmentary detail of FIG. 3.
It will further be seen by reference to FIG. 3 that the fountain bar 30 is formed with a pair of longitudinal and essentially planar land surfaces which extend from each side of the groove 32 and define corresponding pair of coating lips. Thus, the fountain bar 30 has a rearwardlyextending or upstream, planar land or lip 39 and a forwardly-extending or downstream generally planar land or lip 40.
Means supporting the fountain 15 for application of coating material to the web 16 includes a pair of support plates, such as a right hand support plate 43 positioned adjacent one end of the tube 21 and a left hand support plate 44 adjacent the other end, as shown in FIG. 2. The support plates 43 and 44 are suitable cut out or formed at the top to receive the tube 21 in supporting cradled relation therein.
Means pivotally supporting the fountain assembly 15 on the frame 10 includes a pair of operating arms 45, one for each of the plates 43 and 44. The arm 45 at the right hand side of the machine is shown in elevation in FIG. 1, it being understood that a similar arm 45 is employed at the other side of the machine.
The fountain tube 21 and the fountain bar 30 comprising the assembly 15 are supported on the arms 45 in a predetermined angular position. Means for supporting the fountain assembly 15 and for adjusting the relative position of the fountain bar 30 includes pivotal connections formed at 48 joining one end of each of the arms 45 with one of the plates 43 and 44. A threaded bolt 49 extends upwardly from the arm in spaced relation to the pivot 48 and is pivotally secured to the arm by a pin 50. Each of the plates 43 and 44 is in turn, adjustably connected to one of the bolts 48 by means of an eye bolt 51 which has one end threaded into the associated plates 43 and 44 and which is received over the bolt 49 forming a generally right-angle connection. The position of the eye bolt 51 on the rod 49, and accordingly the angular position of the fountain assembly 15 with respect to the arms 45, is adjusted and secured in a predetermined adjusted relation by a pair of nuts 52 and 53 which are threaded on the bolt 49 on opposite sides of the eye bolt 51.
The arms 45 are pivotally supported and connected for unison movement, with a cross-shaft 55. The shaft 55 is extended across the width of the machine and joins the arms 45 for unison movement through an arm extension 56 which has one end welded to the arm and its other end suitably attached for rotation with the crossshaft 55.
The cross-shaft 55 is supported for rotation on the frame 10 at the opposite ends thereof in bearing blocks 58. Each of the blocks 58 is supported in one of the end stands on an adjusting assembly 66. The assembly 60 provides for two adjusting movements, one being vertical and the other being at an angle of 45 to the vertical. As shown in FIG. 1, the adjusting assembly 60 includes a vertical slide support 61 which is guided for vertical adjusting movement on the frame 11. The support 61 has welded thereto, at 45, a gi b plate 62. A block 65 is slidably mounted on the plate 62, and supports one of the bearing blocks 58 on an upper surface.
Means providing for vertical adjusting movement of the assembly 60 includes a threaded bolt 66 which is threaded into a rigid cross member 67 which butts against a cooperating surface of the vertical member 61. Means for effecting movement in the 45 plane includes a similar adjusting screw 68 which is threaded into an extension 69 welded to the 45 frame member 62 and which eifects sliding adjusting movement of the block 65 thereon.
Means for biasing the fountain into coating engagement with the moving web 16 include a pair of diaphragm-type air motors 70. Each of these air motors is mounted on one of the blocks 65 and is connected to an end of the associated arm 45 through a clevis rod 72. The push rod 75 of the air motor 70 may form a suitable threaded adjustable connection with the clevis rod 72, the,
latter which is pivotally connected in driving relation to the rod 45 at a pin '76. The fountain assembly may be brought upwardly into coating relation to the web 16 by applying air under pressure to the diaphragm motor 70 which causes the motor rod 75 to extend and rotate the arm 45 about the axis of the shaft 55. When the fountain is in coating relation to the web, a predetermined air loadingis maintained at the air motors 70 biasing the fountain bar with a predetermined force toward the web 16.
Means for limiting the total movement of the fountain assembly 15 on the arms includes a pair of fixed or rigid stop members comprising a threaded stud bolt 77 and a second threaded stud bolt 78 which are fixedly mounted on the plate in spaced apart relation. The ad justable stud bolts 77 and 78 are positioned to engage the depending finger portion 80 which is welded for movement with the arm 45. Thus, the stop bolt 78 may be adjusted to prevent actual contact between the bar 30 and the adjacent surface of the roll 14, while the adjustable stud bolt 77 may be positioned to define the retracted position of the fountain assembly 15.
During coating there exists a force at the fountain assembly 15 urging the fountain away from the web 16. This force, which is due to the hydrodynamic pumping action of the coating material being applied to the web 16, is constantly balanced by an opposite force exerting through the air motors 70. Accordingly, during coating, the fountain assembly 15 is maintained in a hydraulic and dynamically balanced condition in which the fountain may move with the arms 45 toward and away from the web 16.
The fountain bar 30 is formed with a downstream lip 40 which has a dimension, in the direction of web travel, which is sutlicient to cause complete transfer of the coating film to the web, while the front side 40' of the lip runs dry. It has been found that forming the lip 40 with a suflicient axial dimension in the direction of web travel and with a sharp break between the lip 40 and front edge 40' provides a nip region between the moving web and lip in which the coating material becomes adhered to the web and assumes the velocity of the Web, and the front edge of the lip normally runs dry without overflowing. It has also been found desirable to tilt the fountain bar 30 with respect to the roll 14 so that a converging nip is formed in the direction of web travel.
As shown in FIG. 3, the groove 32 defining the fountain trough has straight parallel sides 32a, and is formed with a depth equal to its width. The planar upstream land surface 39 has a width which is equal to that of the planar downstream land surface 40. When the trough 32 is positioned in coating relation with the web 16, as shown in FIG. 3, the capacity or volume of the trough is substantial compared to the space or volume defined between the lip surfaces 39 and 40 and the adjacent surface of the web 16. Further, in the preferred position of the trough as shown in FIG. 3, the downstream lip 40 converges toward the web 16 while the upstream lip 39 diverges away from the web.
The length and tilt of the lip 40 with respect to the web depends upon the coating conditions for any given installation, including the type and viscosity of coating to be applied, the amount of coating to be applied, and the speed of the web. By way of example, a lip 40 having a land of approximately /2 inch along the direction of web travel has been found to be satisfactory for web speed of approximately 1000 to 3000 feet per minute and more. Since the fountain is supported by resilient means, such as by the air motors 70, the fountain tends to maintain a constant force against the web. The distance fro-m the web may be .001 inch or less up to 0.10 inch or more depending on pumping volume, color viscosity and web speed.
This invention further includes the doctoring apparatus 20 for removing the excess coating which is applied by the fountain assembly 15. The doctor assembly is preferably constructed according to the teachings of the copending application of Coghill, now U.S. Patent No. 3,301,214, issued I an. 31, 1967, and assigned to the same assignee as this application.
The doctor assembly 20 preferably includes a doctor blade supporting frame 82 which is rigidly mounted on a cross channel 83 forming a part of the frame 10 of the coating apparatus. The assembly 20 includes a doctor blade 84 which is yieldingly pressed against the outer surface of the web 16 on the roll 14 by means of a blade holder assembly which is indicated generally at 85. The holder assembly 85 is mounted for pivotal movement on a shaft 86 by arms 88 and is movable on the arms 88 between an advanced or operating position, as shown in FIG. 1, and a retracted position wherein the blade holder assembly 85 is retracted to a position spaced clockwise from the position shown in FIG. 1.
The assembly 85 accordingly includes a pressure bar 90 which extends transversely at least the Width of the web and which is adjustable to vary the force along the length of the blade 84. In the position shown, the blade 84 is clamped between the blade holder assembly 85 and a forward, generally fixed lip or clamp bar 92 of the doctor assembly 20, and may be retracted for the purpose of cleaning, changing the doctor blades 84, and the like.
The assembly 20 further includes an operator in the form of an air motor 94 which is fixedly mounted on a support arm 95 and which is connected to the assembly 85 by a pin 96 for effecting movement of the assembly 85 between the operating position, as shown, and a retracted position.
The bar 92 of the doctor assembly is joined with an edge of a collector pan 97, which also extends longitudinally and coextensively with the doctor assembly 20' and the fountain assembly 15. The pan 97 is positioned beneath the assembly 15 and receives the coating material which is doctored off by the blade 84 and also receives such coating material as may overflow the fountain bar 30. Generally, the latter does not overflow during an actual coating operation. However, prior to the commencement of coating, the supply pump is normally started into operation, and the fountain assembly permitted to overflow. Also, in some circumstances, the coating may overflow the rear lip 39 and be collected by the pan 97, and it has been found that such overflow at the lip 39 does not adversely affect the coating quality or uniformity.
No edge dams are required for the doctor assembly 20, and none are used. However, deckle rods may be employed with the fountain bar 30 primarily to close the opposite open ends of the groove 32. Therefore, bars 98 (FIG. 2) may be adjustably inserted into the opposite ends of the groove and retained by said screws 99.
OPERATION In the operation of the apparatus of the embodiment shown in FIGS. l3 the pump applying the coating material is preferably started to bring the coated material into the transverse tube 31 and overflowing the fountain bar 30, which is collected by the pan 97, and returned to the pumping apparatus. The blade holder assembly 85 is moved into operative position by the air motor 84, while the fountain assembly 15 is raised into coactive relation with the moving web 16.
A metered and regulated supply of air is applied to the air motor 70 to bias the fountain assembly 15 toward the web with a predetermined force. When the coating begins, and the correct force is applied through the motor 70, the lip 40 will cease to overflow and the forward edge 40' will run dry. A certain amount of overflow may occur at the lip 39.
Preferably, the adjustments provided by this apparatus are set so that the fountain bar 30 engages the web 16 On the roll 14 slightly upstream of a vertical center line 7 through the roll 14, as shown by the enlarged detail of FIG. 3. Also, the nip formed between the fountain bar and the web 16 is preferably converging in that the space decreases in the direction of web travel over the lip 40.
The adjustments provided by the adjusting assembly 60, and the tilt adjustment provided by the position of the bolt 51 on the bolt 49, need not be varied after they have once been set except to provide for alignment following a disassembly, such as following regrinding of the roll 14.
The invention accordingly includes the steps of pumping a coating liquid into a trough comprising the fountain 30 and passing a moving web 16 over the open side of the trough to receive a coating liquid therefrom, and the further step of balancing the hydrodynamic forces which tend to move the trough and the web apart with a force, preferably constant, sufficient to hold the trough and the Web in a predetermined coating relationship. This balancing of the hydrodynamic force is effected through the air motor and the mechanical linkages to the fountain assembly 15.
As an example, and without limiting the scope of the invention, a loading of one pound per linear inch of fountain width transverse of the web 16 has been found adequate to coat a web moving at 1000 feet per minute with a coating material which has a 3 /2 pound per three thousand square feet dry coat weight, a 10,000 centipoise viscosity and a wet film thickness of .0l0 inch. As a further representative example, three pounds linear inch of fountain loading has been found satisfactory under the same coating material, dry weight and film thickness with a web speed of three thousand feet per minute.
FIGS. 4-13 The embodiment which is shown in FIGS. 4-17 differs primarily from the embodiment shown in FIGS. 1-3 in that it is adapted for coating in either direction, and accordingly has utility as a double-pass coated which uses a single fountain assembly with a pair of similar doctor blade assemblies. Referring to FIGS. 4 and 7, a coater as shown generally at which includes a frame formed with a pair of end stands, comprising a left end stand 112 and a right end stand 113. The end stands 112 and 113 include lower portions within which much of the control mechanism of the coater is contained, and upper portions which rotatably support a backing roll at 115 on suitable bearings 116. Again, as in the case of the embodiment of FIGS. 1-3, the end stand and backing roll structure may be made according to the teachings of the Jacobs et al. Patent No. 3,079,889.
The apparatus of this embodiment includes a fountain assembly which is generally indicated at in FIG. 4 and a pair of separate doctor blade assemblies 122 and 123. Each of the assemblies 120, 122 and 123 is separately controllable to provide for the coating of the web in either of two directions as indicated by the arrows 124a and 1241; in FIG. 4.
The fountain assembly 120 is mounted for floating limited movement generally toward and away from the backing roll 115 and a web W which is moving thereover, by means of a pair of support arms 125 and 126 which arms are received respectively within the end stands 112 and 113. As shown in FIGS. 5 and 6, the fountain support arms are connected together by a shaft 127 for simultaneous rotation, but each arm is individually controlled by controllable force or bias" means, to be described below.
The fountain assembly consists of a fountain support beam 130 which is of generally rectangular section as shown in FIG. 9, and which extends substantially transversely the width of the coater. Referring to FIG. 8, it will be seen that the fountain assembly beam 130 is supported between a pair of spindles 133 and 134, which spindles extend into the interior of the respective end 8 stands 112 and 113. Vertical adjustment of the fountain assembly 120, at the extreme ends thereof, is effected by means of vertical adjusting slide mechanisms 135 and 136 which, respectively join the spindles 133 and 134 to the fountain beam 130.
The spindles 133 and 134 are, respectively, received for rotation in bearings 138 and 139, carried on the arms 125 and 126. In this manner, the entire fountain assembly 120 is supported between the arms 125 and 126, and while being so supported, the fountain 120 may be rotated within limits about the axis of the spindles 133 and 134.
The mounting arrangement of the fountain assembly 120 on the spindles 133 and 134- and the bearings 133 and 139 provide the means by which the fountain assembly 120 may be moved or tilted from a central coating position shown in full line in FIG. 4 to start-up positions shown in broken outline in which the fountain coating trough is facing oblique to a vertical center line through the back-up roll 115. In the doublepass coater of this embodiment the fountain is movable to the tilted position 120a (FIG. 4) for start-ups in the direction of arrow 124a, and to the tilted position 1201) for start-ups in the direction of arrow 1224b.
Means for rotating the fountain assembly 120 about the axis 140 defined by the spindles 133 and 134 comprises a piston motor (FIG. 5) which is mounted and supported on a downwardly and rearwardly extending portion 146 of the arm 125 (FIG. 5). The motor 145 is connected to the arm portion 146 by a pin 147. The motor piston rod is, in turn, connected to rotate the assembly 120 at a pin 148 which joins a lever arm 150 forming a driving connection to the spindle shaft 133. (Also see FIG. 8 in which the arm 150 and the driving connection by the motor 145 is shown in section.)
Means defining the vertical coating position of the mountain assembly 120 and the tilted positions 120a and 1201) include a threaded rod 152. The rod 152 and the mechanism associated therewith form means for defining the adjustment of the fountain lip angle with respect to the roll 115.
The rod 152 is mounted for rotation on the lower portion 146 of the arm 125 on a threaded support 153. A block or follower 155 and a spacer 156 are slidably mounted on the rod 152. The block 155 is connected for movement by the fountain assembly arms 150 by a pair of straps 157 and 158, one on each side of the block 155 straddling the block, the spacer 156, and connecting to opposite sides of the arm 150 at the pin 148. Also, the block 155 has downwardly extending guides 155 for guided movement on the arm .125.
The erect coating position of the fountain assembly 120 for one condition of coating is defined when the block 155 is in abutment with the spacer 156 and a threaded collar 159, as shown in full lines in FIG. 5. This corresponds to the desired position of the fountain assembly with web movement in the direction of arrow 1241) in FIG. 4. Since the ideal fountain alignment condition varies with the direction of web movement, the spacer 156 is removable from the rod 152 by lifting and may be reversed in its relative position with respect to the block 155, as shown by the broken outline at 156. In this position the block 155 and spacer 156 are movable against another collar 160 to define the vertical fountain alignment for coating in the opposite direction, corresponding to the arrow 124a. The rod 152 is adjustable by turning to make fine adjustments between the nip formed by the fountain assembly 120 and the roll 115. Such preferred fountain coating positions are described below in greater detail in connection with FIG. 17.
The coating apparatus further includes means for supporting the major portion of the weight of the fountain coating apparatus 120, the support arms 125, 126 and associated tilting mechanism. This includes a tare spring assembly 165 for each arm and 126 located in the end stands 112 and 113. The spring assembly in the end stand 112 is shown in detail in FIG. 1 as including a tare spring 166 which is received in compression between 21 cup member 167 fixed to the fountain support arm 125 and an abutment member 168 fixed to the end stand. Also, a stop screw 170 may be incorporated in the stand 168 to define the lowered position of the fountain 120. The tare springs 166 are preferably adjusted so that the fountain 120 rests lightly on the stop member 170, while substantially counterbalancing a major portion of the weight of the assembly and the associated arms and fountain tilting mechanism.
Means for urging the fountain assembly 120 toward the roll 115 into coaction with the moving web W and to counterbalance the hydrodynamic pumping reaction force at the fountain includes a pair of diaphragm air motors and '176, each of which is rigidly connected to a portion of the associated end stand 112 or 113. The air motors are connected by drive pins 178 to an extension stud 179 fixed to the arm 125 or 126. The air motors 175 and 176 correspond in function and operation to the air motors 4-0 of the embodiment of FIGS. l-3, and are operated to urge the fountain toward the web with a predetermined and controllable force while providing floating movement of the fountain with respect to the web. Since a major portion of the weight of the fountain is borne by the springs 166, substantially the total effort of the diaphragm motors 175 and 176 may be utilized to balance the hydrodynamic forces at the fountain during coating.
Details of the construction of the fountain assembly 120 are shown in FIGS. 9l6. The assembly 120 includes a transversely extending, generally cylindrical supply tube 180, which corresponds in function to the tube 21 of the embodiment of FIGS, l-3. The tube 180 is open at its opposite ends and includes suitable pipe unions, such as the unions 181 and 182 of FIG. 8 for the supply of liquid coating material simultaneously to the opposite ends thereof. It is, of course, within the scope of the invention to apply coating material to one end only of the fountain supply tube 180 where the width of the coater is such that single-ended supply is satisfactory. The tube 180 also includes a plurality of longitudinally spaced openings 183 formed along the top thereof.
Mounted on the supply tube 180 is a fountain bar 185. The upper portion of the fountain bar 185, as is best shown in FIG. 13, is formed with a longitudinal trough or groove 186 which is generally rectangular in section, except at the ends of the bar 185, at which point it is undercut for receiving a deckle bar, described below. The groove 18-5 is in communication with a plurality of circular openings 188 which extend from the bottom of the groove 186 through to the bottom of the bar 185. The openings 188 correspond in spacing to the tube openings 183 and receive the coating material from the tube 180.
The upper surface fountain bar is divided by the groove 186 and forms an inner lip 190 and an outer lip 192, as shown in the enlarged detail of FIG. 11. Each of the lips 190 and 192 define land surfaces which join the trough formed by the groove 186 and which extend the full effective longitudinal extent of the fountain bar groove 186. The planar upper surfaces of the lips 190 and 192 are of substantially equal area, and permit coating of the web in either of two directions of web movement.
The fountain bar 185 is sealed to the tube 180 by suitable sealing strips 195 and 196 extending longitudinally of the fountain bar at opposite sides of the row of openings 188, as shown in FIG. 11. An optional metering sleeve or bar 200 may be positioned between the fountain bar 185 and the tube 180, and contains metering openings 202 which are aligned between the openings 188 in the fountain bar and the corresponding openings in the tube 180. The metering sleeve 200 may be used where it is desired to control the rate of pumping at the fountain. However, the sleeve may be omitted where the pumping rate is controlled by the coating pump.
Means securing the bar 185 in superimposed sealing relation to the tube 180, with the optional metering bar 200 sandwiched therebetween, includes a plurality of identical clamp assemblies 205 which are positioned in longitudinally spaced relation along the length of the tube 180. One of the clamp assembles 205 is shown in elevation in FIG. 10 as including a pair of identical opposed clamp members 206 and 207. The upper ends 208 of the clamp members are received in the bar 185 in opposed relation within suitable longitudinal grooves 210 and 211 formed in the opposite sides of the bar. The clamp members 206 and 207 are received in generally encircling relation to the tube 180 and have lower portions 215 which are held in abutting relation by a cross bolt 216 extending beneath the tube 180 between the clamp members 206 and 207. Each of the clam members 206 and 207 is also formed with ap air of outwardly or transversely extending ears 220, such as shown in FIGS. 8 and 10. Semi-circular collars 222 are received in encircling relation to the bottom of the tube 180, and are formed with outwardly extending tabs 223, 224 which are engaged by threaded bolts 225 received through the ears 220. By tightening the bolts 225, the clamp members 206 and 207 are caused to draw the fountain bar 185 firmly down against the tube 180 and retain these parts in rigidly assembled relation.
The fountain assembly 120 further includes hanger support means for supporting the tube and fountain assembly on the support beam 130, and one of these assemblies is shown at 230 in FIGS. 8 and 9. A plurality of the hanger assemblies 230 are employed longitudinally of the fountain assembly 120 in alternating relation to the clamp assemblies 205 of FIG. 10, as shown in FIG. 8. The assemblies 230 provide the means by which the fountain bar 185 and tube 180 are supported on the beam 130 for movement therewith, and further provides the means by which vertical adjustment and horizontal linearity of the fountain bar are obtained.
The hanger ass mblies 230 each include a pair of rigid upright support members 232 and 233 which are welded in spaced apart relation to an upper surface of the beam 130, and which are fixedly spaced apart by and welded to an inverted U-shaped spacer 235. A pair of identical hanger brackets 240 and 241 have lower ends which are adjustably secured respectively to the upright supports 232 and 233 by bolt pairs 244. The bolts 244 pass through enlarged openings in the hanger brackets 240 and 241 and into threaded openings in the supports 232 and 233 and provide for limited vertical adjustment of such brackets.
The upper ends 245 of the hanger brackets 240 and 241 are turned inwardly toward each other and are also received within the fountain bar grooves 210 and 211, in the same manner that the tube clamp members 206 and 207 are so received. Means providing for separate vertical alignment of each of the hanger brackets 240 and 241 comprise pairs of interfitting keys 248 and 249 which are received respectively within suitable horizontally disposed key slots formed in the hanger brackets 240, 241 and in the vertical supports 232, 233. The keys are provided with cooperating sloping interfitting tongues and grooves at 250 and are movable transversely one to the other within their respective key slots to effect the fine vertical adjustent of the hanger brackets 240 and 241 with respect to the cross beam 130. In this manner, desired leveling and cross straightne'ss of the metering l ips 190 and 192 of the fountain is obtained throughout the length thereof.
The fountain assembly 120 further includes a vent by means of which entrapped air may be separated and removed from the tube 180. This vent, as shown in section in FIG. 12, consists of a short stub section of pipe 252 which has a central opening 253 communicating with an elliptical opening 255 formed in the tube 180. The stub pipe 252 is clamped to the tube 180 by a pair of draw bolts 256 welded at their upper ends to the pipe 252, and a strap 257, firmly securing the tube 250 by nuts 25% against a seal 259. In the forward or rearwardly tilted position of the fountain assembly 120, the elevated end of the stub pipe 252 may be opened either manually or by a controlled valve to separate entrapped air from the coating material, and then closed.
The fountain assembly 120 further includes means for blocking off the opposite ends of the fountain trough or groove 136 comprising deckle rod assemblies 260 as shown in FIGS. 14-16. A deckle rod 262 is slidably received within the groove 186 at one of the ends of the bar 185. The fountain bar 185 is undercut at 263 to accommodate corresponding flanges 264 on the dcckle rod 262. The rods 26-2 have upper surfaces which join flush with the fountain bar lips. A C-shaped two-piece clamp 265 and 266 is mounted on each end of the fountain bar 185 in the longitudinal groove 210 and 211. A bolt and wing nut combination 268 secures the deckle rod 262 in a predetermined position on the bar 185 between the clamps 265 and 266. Suitable elastomeric sealing strips 269 may be employed between the deckle rod 262 and the sides of the groove 186 to provide an effective seal.
The cross beam 130 of the assembly 120 may include temperature stabilization means, and to this end water conduits in the form of inverted U-shaped channels 275 and 27 6 are welded, respectively, along the lower and upper surfaces of the beam 130. As shown in FIG. 8, suitable inlet and outlet water conduits, such as the conduit 277 and 278, may be employed to admit water at a controlled temperature through the passageways formed by the channels 275 and 276 to stabilize the temperature of the support beam 130.
The fountain assembly 120 further includes suitable shrouds for deflecting the coating material for return to a collector pan. As shown in FIG. 9, upper shrouds 280 extend the length of the fountain along each side thereof and have ends which form a seal at the fountain bar along sealing strips 282. The shroud 280 joins the bar 135 just below the fountain lips 190 and 132 and forms an enclosure for the mechanisms mounted on the beam 130. The shroud 2 80 is formed with downwardly depending sides which are suitably secured such as by bolts 283 to the beam 130. Also, the bottom portion of the beam is preferably covered by a further shroud 285 also retained by the bolts 283. The shrouds 280 and 285 may be formed of stainless steel clad sheet material.
The apparatus of this embodiment further includes a pair of substantially identical doctor blade assemblies which have previously been indicated at 122 and 123. The doctor blade assemblies are selectively brought into operation or moved to a retracted position depending upon the direction of coating. The doctor assemblies 122 and 123 are respectively supported and mounted on generally rectangular beams 300 and 301 which extend between the stands 112 and 113, as shown in FIG. 7. The beams 300 and 301 are provided at each end with separate vertical slide adjustments 302 and 303 which comprise a blade angle control for the associated doctor blade. The vertical slide mechanisms are similar to the mechanisms 135 and 136 of the beam 130. Each includes a spindle shaft which is pivotally mounted to the stands 112 and 113 on bearings 305. However, the vertical slide adjustment mechanisms 303 on the right-hand side of the machine, as shown in FIG. 7, are each formed with a spindle shaft 306 which extends into the interior of the right-hand stand 113, as shown in FIG. 6.
Piston-type air motors 310 and 311 are connected selectively to rotate the beams 300 and 301 between an operating position in which the doctor blade is in engagement with a web and a fully retracted or inoperative position. The operating position is defined and controlled by threaded adjustment stop members 312 and 313 which contact an abutment arm 314 on the shaft 306, as shown in the left-hand portion of FIG. 6. The adjustable stop member 312 and 313 comprise blade loading adjustments by means of which the force exerted by the associated doctor blade on the web may be controlled. The fully retracted position of the doctor blade assemblies 122 and 123 may be defined by the stroke of the motor 310 and 311.
The doctor assemblies 122 and 123, insofar as they relate to the blade mounting and positioning mechanism, are preferably made according to the copending application Ser. No. 350,910, identified above, and as described in connection with the embodiment of FIGS. 13. The blade mounting mechanism, as shown in FIG. 7, includes a plurality of backing plate support stands 330 which comprise means for mounting the doctor backing plate 332 on the doctor support beam 300 or 301. The support stands 330 are positioned in spaced relation on the beam transversely of the coater, and also have means providing a thermal expansion joint permitting the expansion of the doctor blade assembly transversely of the coater as it becomes heated by the application of a hot coating material to the web. Accordingly, the stand 330 is made with two interfitting parts including an inner portion 335 which is mounted directly to the upper surface of the support beam 300 or 301 and an outer portion 336 on which is mounted the backing plate 332. The outer portion 336 is mounted for limited transverse sliding movement on the inner portion 335 by a pair of pins 337 and 338, one of which is shown in the broken away portion of FIG. 7. The pins 337 and 338 form rails on which the backing plate 332 and the associated doctor mechanism may slide with thermal expansion and contraction of the parts transversely of the coater.
The doctor assemblies 122 and 123 further include doctor blade clamping and pressure adjusting means for supporting a doctor blade 340 and for making longitudinal adjustments of the pressure on the blade 340. This mechanism is substantially as disclosed in said application Ser. No. 350,910 and described in connection with FIGS. 13, and includes a plurality of force-applying diaphragmmotor assemblies 342 which are mounted on the backing plate 332 in longitudinal spaced relation between the support stands 330. The motor assemblies 342 include a diaphragm-type air motor 345 which is rigidly connected by an arm 346 to the backing plate 332. The actuating rod of the motor 345 is connected to rotate a blade holding arm 347 about a pivot pin 348, as shown in FIG. 5, and is operable to move the blade pressure bar assembly 350 into engagement with the backing plate 332 with the blade 340 clamped therebetween.
The doctor blades 340 may be adjusted to contact the web at varying blade angles, such as the wide angle X and the narrower angle Y as shown in the diagram of FIG. 19. Adjustments of blade angle may be made by regulating the vertical slides 302 and 303 supporting the beams 300 or 301, and by regulating the blade loading adjustments 312 or 313. Thus, to increase the blade angle, the slide mechanisms are operated to lower the beam while the associated blade loading adjustments 312 or 313 is rotated to bring the blade 340 into desired contact with the web on the backing roll. Conversely, to increase the blade angle requires that the blade height adjustments be increased and the blade loading adjustments be backed off proportionately.
The blade angle adjustments of this invention provides a means by which the dwell time between the fountain coating bar and the doctor blade may be controlled or varried. Accordingly, this mechanism provides the means by which the doctor blade 340 may be varied in position relative to the fountain bar to obtain a given dwell time prior to doctoring for any given web speed or other operating conditions. For example, relatively high blade angles, such as 50 or more, may be used to provide a short dwell time while relatively low blade angles, such as 25 or less may be used to provide a long dwell time.
A suitably formed collector pan 360 is positioned on floor-mounted support brackets 361 and 362, as shown in FIG. 7. The pan 360 is preferably tapered downwardly at the ends to drain through openings 364 and 365 at the opposite ends thereof. However, the pan may be designed, for narrow machines, to drain at one end only. The pan 360 is suitably configured similarly to the pan 97 of the embodiment of FIGS. 1-3, to receive the excess coating which is doctored off by either of the blade assemblies 122 and 123-, and any excess coating which flows down over the fountain assembly 120 prior to or during coating conditions.
OPERATION-FIGS. 1-18 The operation of this embodiment is mainly selfevident from the foregoing description and from the description of the operation of the embodiment of FIGS. 1-3. The basic principle of operation of the fountain comprises the means supporting a fountain bar and web support for limited movement toward and away from each other, the means for applying a coating liquid to the fountain bar for application to the web, and the means for urging the fountain bar and web support toward each other.
In coating, preferably the doctor blade assemblies 122 and 123 are fully retracted by the air motors 310 and 311 and the fountain assembly 120 is tilted toward the direction of web movement and oblique to a vertical center line through the backing roll. The pumping of the hot color or coating liquid is begun. Preferably, the fountain assembly 120 is rotated from its tilted to its substantially vertical position while fully lowered on the arms 125 and 126. The extent of vertical movement of the fountain assembly 120 on the arms need only be suificient to assure clearance of the fountain lips 190 or 192 as the fountain is brought to its erect predetermined position, such as one-eighth inch to one inch.
The fountain lip angle adjustment screw 1521 is preferably adjusted to provide a converging nip relationship between the fountain lips and the web W, as shown in slightly exaggerated form in FIG. 17. FIG. 17 shows a typical coating condition where the fountain assembly 120 is being urged into coating position with a web W by the air motors 175 and 176, and in which the fountain is tilted slightly rearwardly of the center line 370 of the roll to provide a converging nip between the forward coating lip 192 and the web W for coating in the direction of the arrow 124a. This relationship has been found to provide superior coating results, and forms a Wedge of coating material bet-ween the fountain and the web, and further provides a sharp break at the downstream edge 192:: of the lip 192 which cleanly shears the coating ma terial leaving all of the material adhered to the exposed surface of the web while the lip at 192a runs dry.
A further arrangement for defining a converging nip in the direction of web travel is shown in FIG. 18. A taper 350- is in the fountain lip 192 so that it slopes toward the web W with increasing distance from the trough 186. It has been found that a 3 slope, for instance, reduces the degree of offset of the center line of the fountain bar 185 with respect to the center line 370 of the backing roll while defining a converging nip relationship between the downstream lip and the web. Also, the rear lip 190 may be provided with a taper which slopes away from the web in the direction of travel. This closes the gap of the fountain and reduces leakage against the incoming web.
The doctor blade assembly 122 or 123' is brought into position against the associated stop 312 or 313 immediately prior to applying air pressure to the diaphragm motors 175 and 176 so that the associated doctor blade 340 is in operative position on the web immediately prior to raising the fountain into coating relation with the web W. This reduces burning of the doctor blade on the dry web to a minimum. The air pressure to the air motors 175 and 176 is regulated to apply a desired upward force 'on'the fountain assembly which force is balanced by an opposite hydrodynamically created force at the fountain bar 182. The examples and method stated in connection with the embodiment of FIGS. 1-3 apply equally to this embodiment.
As has been noted, any entrapped air within the tube 180 may be removed at the vent tube 252. The edge dams or deckle rods 260 may be set up and adjusted prior to coating to block off a predetermined extent of the trough 186, according to the width of the web to be coated. The coating which is applied by the fountain applicator of this invention is applied uniformly across the length of the web. No additional or external edge dams are required.
It will therefore be seen that this invention provides a controlled fountain coater and method in which the relationship of the fountain may be controlled with respect to the web and in which the fountain is free floating on a film of coating, the thickness of which is determined by the pumping rate, the viscosity of the coating, and the force by which the fountain is biased against the web. Additionally, the doctor assemblies 122 and 123 are separately controllable and are adjustable in blade angle and in point of incidence with the web to vary the dwell time between the fountain and the doctor blade. Since the fountain in this embodiment is held in coating position by the air motor 145 against the adjustable stop or lip angle mechanism, in the event of the web breaking the force of build up ofthe web on the fountain assembly will cause it to rotate about its axis away from the broke build up. This is an important advantage when coating board, and effectively prevents damage which would otherwise occur to the fountain assembly.
While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.
What is claimed is:
1. Apparatus for coating a moving web supported on a backing roll, comprising a fountain bar, spaced side walls defining in said bar a trough extending generally transversely of the web to be coated and open at the top thereof, said bar including a first planar land surface coterminous with the adjacent said wall of said trough along one edge thereof and extending for a finite distance from said edge generally in the direction of web movement, said bar including a second planar land surface having one edge thereof coterminous with the wall of said trough opposite said first land surface and extending for a finite distance from said edge thereof oppositely to the direction of web movement, means for supplying liquid coating material to said trough, supporting means for maintaining said bar in coating position wherein said first land surface converges toward the web away from said trough and said second land surface diverges from the web away from said trough, and said trough being proportioned to define a volume which substantially exceeds the volumes defined between said land surfaces and the web in said coating position of said bar.
2. Apparatus as defined in claim 1 comprising means forming a pivotal mounting between said bar and said supporting means providing for angular adjustment of .the converging and diverging relationships between said land surfaces and the web.
3. Apparatus as defined in claim 1 comprising frame means, means mounting said supporting means for movement on said frame means through a range carrying said bar to and away from. said coating position, and means connected to bias said supporting means in the direction to urge said bar toward the web in force-opposing relation to the hydrodynamic forces at said trough and land surfaces urging said bar away from the web.
4. Apparatus as defined in claim 1 comprising frame means, means mounting said supporting means for movement on said frame means through a range carrying said bar to and away from said coating position, and means forming a pivotal mounting between said bar and said supporting means providing for angular adjustment of the converging and diverging relationships between said land surfaces and the web.
5. Apparatus as defined in claim 1 wherein said side walls of said trough are substantially parallel with each other and perpendicular to the bottom wall of said trough to provide said trough with a substantially rectangular cross section.
6. The apparatus of claim 1 in which said supporting means comprises a frame, a pair of support arms being pivotally mounted on said frame, means pivotally supporting said bar on said arms, and means on said arms connected to pivot said bar between a starting position in which said trough is tilted in the direction of web travel obliquely to a vertical centerline through said roll to said coating position in which said land surfaces are positioned in otfset relation to said roll centerline.
7. The apparatus of claim 6 further comprising air motors connected to said arms for urging said fountain bar toward said backing roll, and spring means in forcingrelation to said air motors carrying a major portion of the weight of said arms and said fountain bar sup-ported thereon.
8. Apparatus as defined in claim 1 in which said planar land surfaces are in a common plane.
9. Apparatus as defined in claim 1 comprising a pair of deckle bars positioned at the opposite ends of said trough, each of said deckle bars including a deckle rod slidably received in said trough and having an upper surface proportioned to bridge the space between said coterminous edges of said walls and land surfaces, and elastomeric strip sealing means received between said bar and said side walls of said trough for holding and sealing the associated said rod in each adjusted position thereof.
10. Apparatus as defined in claim 9 comprising internal groove means in said trough, and complementary 40 flange means on each of said deckle bars slidably received in said groove means and cooperating therewith to maintain said upper surface of said bar in said bridging relation with said groove wall edges.
11. Paper coating apparatus comprising "a' fountain bar, means on said bar forming a generally rectangular coating-receiving trough having opposed side walls extending transversely to a paper web to be coated and being open at the top adjacent an exposed surface of said web, means supporting said web in coating relation-to said trough, said trough further having planar coating land surfaces extending coterminously with said trough transversely thereof from an upstream edge thereof and from a downstream edge thereof, coating supply tube means, means in said trough bottom defining a plurality of longitudinally positioned passageways opening into said trough and said coating supply tube means, means in said fountain bar at said trough defining an undercut groove extending at least partially transversely of said trough, a deckle rod having a portion slidably received in said trough groove and having an upper surface which is flush with said land surfaces, and elastomeric strip sealing means received between said deckle bar and the walls of said trough providing a seal defining the effective width of said trough and blocking communication between said trough and said passageways.
References Cited UNITED STATES PATENTS.
Guggenheim l1841l WALTER A. SCHEEL, Primary Examiner.
J. MCINTOSH, Assistant Examiner.
US. Cl. X.R.