US3245378A

US3245378A - Doctor blade holders for a papermaking machine

Info

Publication number: US3245378A
Application number: US194415A
Authority: US
Inventors: Caple Ira; Schubart Kal Paul
Original assignee: Kimberly Clark Corp
Current assignee: Kimberly Clark Corp
Priority date: 1962-05-14
Filing date: 1962-05-14
Publication date: 1966-04-12
Anticipated expiration: 1983-04-12

Description

April 12, 1966 1. CAPLE ETAL 3,245,373

DOCTOR BLADE HOLDERS FOR PAPERMAKING MACHINE Filed May 14, 1962 6 Sheets-Sheet 2 I. i/3119120 ll J3 April 12, 1966 l. CAPLE ETAL DOCTOR BLADE HOLDERS FOR A PAPERMAKING MACHINE 6 Sheets-Sheet 5 Filed May 14. 1962 April 12, 1966 1. CAPLE ETAL 3,245,378

DOCTOR BLADE HOLDERS FOR A PAPERMAKING MACHINE Filed May 14, 1962 6 Sheets-Sheet 4 April 12, 1966 1. CAPLE ETAL 3,245,378

DOCTOR BLADE HOLDERS FOR A PAPERMAKING MACHINE v Filed May 14, 1962 6 Sheets-Sheet 5 I 162 m9 61 W III 166 I O 1 54; ii 1 62 5 1'0 1' 6 J86 5:? 16a E April 1966 I. CAPLE ETAL 3,245,378

DOCTOR BLADE HOLDERS FOR A PAPERMAKING MACHINE 6 Sheets-Sheet 6 15/ 45-50 pm AIR LOAD LOAD 4 .96

I I -L 102 63 ao-mo PSI AIR L x POSITION 7 1; BACK sun:

mm i 5 310.4.

United States Patent C) 3,245,373 DOCTGR BLADE HOLDERS FOR A PAPERMAKING MAQHINE Ira Qaple and Kai Paul Schuhart, Neenah, Wis, assignors to Kimberly-Clark Qorporation, Neenah, Wis, a corporation of Delaware Filed May 14, 1962, Ser. No. 194,415 Claims. ((31. 118-126) This invention relates to coating devices for applying coating compositions and is particularly directed to mechanisms for the coating of paper webs.

It is customary in the paper manufacturing and allied fields to apply an excess of coating composition to a Web and to then blade the coating with a flexible doctor blade. In the blading operation the excess of the coating composition is removed from the web while the remainder of the coating material is troweled or smoothed onto the web surface. For such purpose the traveling web, during the blading procedure, is usually supported as on a rotating resilient backing roll. The flexible doctor blade may be simply a thin metal blade suitably provided with a ground longitudinally extending blading edge or it may be a small diameter flexible rod supported on an edge of a flexible plate element. Such doctor blade is presented to the web traveling on the backing roll to form an acute angle with a tangent to the backing roll at the line of blade contact.

Blades, blade holders, and the assemblies or mountings for such devices are subject to a number of deficiencies, including difliculty of accurate alignment; retention of alignment under applied pressures; change of line of contact of the blade edge with the backing roll with change of blade holder angle; and change of angle with pressure, blade wear and change of blade holder position. Such variable factors, some of which may occur during the coating operation, lead to quality variations in the coated product.

A primary object of the present invention is to provide a novel self-aligning suspension arrangement of a doctor blade holder assembly in which the doctor blade holder angle is substantially independent of blade wear, pressure applied to the assembly, and change of position of the doctor blade holder relative to a backing roll.

An important object of the present invention is the provision of a novel combination of suspension arrangement and doctor blade holder assembly in which the combination is composed of relatively simple, readily assembled parts so constructed and arranged as to preclude misalignment or derangement of the same.

A particular object of the present invention is to provide apparatus for the retention of a doctor blade in which blade pressure may be held substantially constant in a simple and effective manner independently of blade angle or blade wear.

Yet another object of the invention is the provision of a doctor blade holder assembly for the coating of paper webs, and which arrangement has a high degree of sensitivity.

In a preferred embodiment of the invention a doctor blade holder assembly is itself carried between parallel, depending swinging supports which are articulated to ends of the assembly and which form a type of parallelogram suspension. Such supports are at lea-st four in number, at least two being disposed on each opposed end of the assembly and so carried on universal joints that the doctor blade holder assembly is self-aligning under applied pressure.

Pressure is itself preferably applied substantially radially of the backing roll by fluid pressure cylinders acting on the assembly to move the blade directly into the back- 3,245,378 Patented Apr. 12, 1966 ing roll or directly away from the backing roll when unloading the blade. By this arrangement, blade pressure against the backing roll is maintained constant regardless of blade wear.

The blade holder and its mounting are desirably pivoted for movement relative to the depending supporting arms. The holder is arranged to pivot about the line of contact of the blade with the backing roll; thus the line of doctor blade contact with the roll may be maintained even though blade angle and blade holder angle are changed.

The overhead suspension arrangement of the blade holder assembly facilitates the mechanical arrangement of the equipment. Thus, to effect a backing roll change, it is merely necessary to swing the assembly out of the way, rearwardly away from the roll. In most arrangements, in accordance with the invention, this does not require detachment of the assembly to any degree; thus, no time is lost in realigning or adjusting equipment components. Additionally, ball and socket suspension provides for simplified blade holder reciprocation while maintaining pressure application in a constant direction relative to the backing roll.

In the preferred embodiment of the invention the excess of coating is applied at a first applicator nip, and the web with the excess thereon is carried on the backing roll to a nip formed by the blade and roll; the dwell time between the nip is readily controlled in the procedure of the invention.

The invention will be more fully understood by reference to the following detailed description and accompanying drawings wherein:

'FIG. 1 is a fragmentary perspective view illustrating a preferred embodiment of the invention;

FIG. 2 is a left hand end view of the embodiment of FIG. 1, particularly illustrating the cooperative relationship of the suspension system, the assembly, and the fluid pressure means;

FIG. 3 is a front view on a reduced scale of the embodiment of FIGS. 1 and 2, with the coating supply removed, taken from the operators side of the mechanism;

FIG. 4 is a plan view partially in section of the doctor blade holder assembly;

FIG. 5 is a considerably enlarged view and taken on line 5- 5 of FIG. 4;

FIG. 6 is an elevational view of the structure of FIG 4;

FIG. 7 is a detail view illustrating the ball and socket suspension arrangement:

FIG. 8 is an enlarged and fragmentary view of the coating device, partially in section, and particularly illustrating the blade holder and blade;

FIG. 9 is a fragmentary view illustrating the assembly in retracted position relative to the backing roll of the embodiment illustrated in the preceding figures;

FIGS. 10A and 10B are schematic views of control equipment useful in the described preferred embodiment; and

FIG. 11 is a schematic elevational view of a further embodiment of the invention.

In the detailed description which follows, corresponding parts, where convenient, are designated with similar numerals. Also, since opposite ends of the assembly are similar, in general reference is made to the structural arrangement of one end.

L'i broad aspect the arrangement of invention includes: (a) the blade holder assembly designated generally at 10; (b) the suspension system designated generally at 12;

and (c) the pressure control system designated generally In essence, the blade holder assembly is cradled by the suspension system for movement toward and away from a backing roll 16. Fluid pressure means of the control system position the blade holder assembly in one of four positions:

(1) fully retracted from the backing roll;

(2) advanced to a stop position adjacent but not in contact with the backing roll;

(3) in kiss-contact with the backing roll; or

(4) under pressure against the backing roll.

In the full pressure operating position (FIG. 2) a web of paper 18 carrying an excess of coating composition 19 is passed to the nip 2% formed between the flexible blade illustrated at 73 in FIG. 8 and the resilient rubbercovered backing roll 16; the excess of coating in the embodirnent illustrated is applied to the web at nip 22 formed between the backing roll and applicator roll 23. The applicator roll rotates in pan 24 in the direction indicated by the arrow and carries the coating composition 19 to the nip 22, where the coating is applied to the web traveling on backing roll 16. The excess of coating which is bladed off at nip is returned to the system (FIG. 2).

The blade holder assembly The assembly 10 includes a longitudinally extending carrier 25 (FIGS. 4 and 5) which is generally triangular in cross-sectional shape, hollow, and formed of relatively wide, longitudinally extending

plates

26, 27, and 28 suitably welded together. Carrier 25 has end plates or panels 30 at its opposed ends, closing the structure and forming with the longitudinally extending plates a mount for the blade holder; the end plates 39 are of generally triangular shape but have rounded surfaces (FIG. 5) and project forwardly from the carrier (PEG. 2) toward the backing roll 16. The carrier and panels are of greater length than the backing roll, and the panels extend beyond the backing roll ends an equal distance on each end of the roll. Forwardly also, welded to the junctures of

plates

27, 28 and extending longitudinally over an intermediate portion of the carrier length, is a holder tray 33 for the blade holder structure.

The end panels 30 each project well forwardly of the tray 33 (FIGS. 4 and 5) and terminate in an apex which is apertured to receive a bushing 35. In the embodiment shown, each bushing also receives a companion securing member or plate 36. Each plate 36 in the described embodiment is also of generally triangular shape (FIG. 2) and each plate 36 overlies an end panel 30. A nut and bolt assembly 34 retain the panel and plate. A pin in slot arrangement opposite the bushing 35 provides for relative pivotal movement between a companion securing plate 36 and end panel 30; the slot 37 is formed arcuately through the plate 36, and threaded pin 38 in the slot is engaged threadedly with a panel aperture 39 (FIG. 5) to retain the panel (and the blade holder assembly 19) in adjusted angular position when the threaded pin is urged into engagement with the securing plate at the slot.

For relative movement of each plate and panel angularly, a manually operable adjustment designated at 40 is provided (FIGS. 2, 5 and 6). This adjustment includes a projecting lug 42 carried fixedly on panel 30 and having a V slot 43. The lug 42 receives freely therethrough a threaded eyebolt 44, the eye 45 of which is journaled on and retained by a shouldered and headed stud 47 carried by and threaded into a cooperating securing plate 56. The eyebolt 44 projects forwardly (FIG. 2) toward the backing roll and receives a washer 48 having a V projection 49 which engages in the V slot 43 of a lug 42; a nut 59, threaded on the journaled eyebolt, when rotated causes travel of the panel 30, lug, and eyebolt (in rotalion) and, accordingly, relative angular movement of the panel and securing plate, while the washer remains engaged with the lug and provides for smooth rotation of the nut.

Each securing plate 36 is itself retained fixed against angular movement relative to the end panels; the parallel depending swinging support arms 51 of the suspension system inhibit such movement while otherwise providing for free movement of the assembly. As shown, two arms 51 having such suspension terminal eyes 52 are journaled on studs 53 and are suitably retained by conventional retaining rings 54, 55 (FIG. 7). The bearing shoe 56 is free to move on the fixed universal or ball type bearing surface 57 which is itself retained positioned between side members 58 and cooperating bolt 59.

Additionally, a fixed shouldered shaft projction 69 of a securing plate 36 receives a terminal eye 61 of a piston 62 of an air cylinder 63. The terminal eye is similarly retained on projection 66 by conventional retaining rings.

A portion of the peripheral surface of each securing plate 36 is graduated in angular degrees (FIG. 6) to provide an angle scale 64. An angle indicator 65 (FIG. 3) includes a pointer 66 and is fixedly retained by a panel 39 in cooperable relation with scale 64. Thus, the carrier and end panels of the blade holder assembly which form the blade holder mounting may be adjusted in fixed known angular relationship with the securing plates of the assembly and, accordingly, also with the backing roll. The angle scale indicates the acute angle formed between a tangent to the backing roll and the blade holder.

In this preferred embodiment the blade holder is itself separate from the carrier. The holder includes a lower clamp element 67 (FIG. 8) formed with a depending key 68 which snugly engages in a longitudinally extending slot 69 of the tray 33; an upper clamp element 70 is recessed to receive upstanding key 71 of the lower clamp element. Such clamp elements extend longitudinally with the tray 33 and are retained thereon by a plurality of threaded bolts 72 spaced longitudinally of the carrier; tl e blade 73 is held between the clamp elements 67, 76 by suitable bolts 74 spaced longitudinally of the holder itself and suitably alternately with bolts 72 (FIG. 3). Thus, the blade and holder are readily pre-assembly for mounting on the tray. Blade 73 in the holder is positioned in abutment rearwardly with a machined, smoothed forward face of key 71. The projection of the blade beyond the forward lip 75 of the holder is customarily about /4 inch. When positioned, the blade forward edge 76 is in longitudinal alignment with the centers of the two bushings 35 of the blade holder assembly.

The suspension system The suspension arms 51 are provided on each longitudinal end (FIGS. 1 and 2) of the blade holder assembly. As noted, terminal eyes 52 are articulated to studs on the securing plates. The suspension arms of each end preferably lie in parallel planes which extend perpendicularly to the backing roll face. Upwardly the arms or ties rods 51 are journaled on suitable bearings. The structural arrangment of the arm connections is shown most clearly in FIG. 7.

Referring again to FIG. 3, a hanger 30 of bifurcated structure extends downwardly, rearwardly and fixedly receives the fixed shafts 53 which extend through the bifurcated structure and support the suspension arms. The hanger projects laterally on each side of the bifurcation and is provided with vertically extending slots 82 through which bolts 84 are passed to secure the hanger to the machine frame 85 in adjusted position. An angle iron 86 carried fixedly by frame 85 receives bolts $7 which are utilized in adjusting the vertical height of the hanger 80.

As noted, the hanger 80 projects downwardly rearwardly; one bearing is horizontally spaced from and vertically below the other and thus a line passed through the centers of the bearings is at an angle with the horizontal. This angle is preferably equal to the angle formed by the radius R of the backing roll with the horizontal; this radius R is the radius which extends to the line of contact of the blade with the backing roll. The arms 51 are all of equal length and, accordingly, the rearward arms on each side are articulated to the blade holder assembly in lower vertical positions than the forward arms. Such arrangement provides not only for free movement of the blade holder assembly but serves to urge the leading edge of the assembly upwardly in its travel to the backing roll and to provide for mechanical balance of the assembly itself.

The control system Power is supplied to the arrangement through fluid pressure means; in the specific embodiment described air cylinders are utilized.

As shown in FIGS. 13 inclusive, brackets 90 project downwardly rearwardly from a lower portion of frame 85 on either end of the assembly and below the hangers 89. Supported in the bracket (FIG. 2) is the air cylinder 63, the support being such that the cylinder is free to move in any direction. Thus, rearwardly (FIG. 2) a universal joint 92 retains the cylinder supported in floating condition between the bracket top 93 and bottom 94; forwardly (FIG. 2) the cylinder piston rod 62 terminates in the eye 61 which is received on the bearing of fixed shaft 60 (FIG. 5) projecting from a securing plate 36 (FIG. 4). To provide protection for the piston rod from corrosion due to coating spray or the like, each piston rod is preferably provided in operation with a suitable covering bellows (not shown). Since the bearing (FIG. 7) permits free movement of the piston rod at one end and the universal 92 permits free movement of the cylinder, the cylinder pressure may be exerted essentially radially of the backing roll. Thus, in the embodiment described, the pressure on the blade holder assembly may be essentially radially of the backing roll and the pressure exerted by a blade on a web passing on the backing roll is then in substantially direct relation to applied air pressure. Air cylinder inlet and

outlet ports

98, 106 are connected by flexible lines 192 to the source of air supply designated at 1M in FIG. A to provide for free cylinder pivotal movement horizontally and vertically.

The application of air pressure is controlled to prevent a misalignment in the advance of the assembly; to provide for a kiss-contact loading of the assembly initially and prior to full loading of the blade; and to provide a controlled preset load pressure.

Since the assembly is self-aligning, it is desirable to rovide stops to insure of end to end alignment of the assembly while the blade is yet spaced from the roll. In the described embodiment pivoted stops designated generally at 104' (FIG. 2) are employed. The stop member 195 (FIG. 9) in the form of a roller is carried on a depending end portion 106 of a latch 107 which is pivoted on ears 168 carried fixedly by the casing of the air cylinder 63. The latch extends transversely of the assembly length; intermediate the latch length and adjacent the stop member each latch is pivoted to a lever system.

The lever system includes for each end of the assembly a latch rod 111 having upper and

lower rod portions

112, 113 respectively, joined by a turnbuckle 114; the latch rod 111 terminates at each end in an eye as at 115, 116, the eye including a suitable hearing. The cylinder brackets 96 are cut out to provide for passage of the latch rods. The terminal eye 115 of the latch rod (FIG. 9) is journaled on ears 117 of the latch 107 while the upper eye 116 is journaled on a latch arm 118. Latch arm 118 is itself supported for rotational movement with a cross-shaft 119 on pillow blocks 120; such blocks (FIG. 2) depend from hanger 80.

As thus described, the lever system is similar at each end of the blade holder assembly. However, at the left hand end (FIG. 2) the shaft 119 has fixed thereto a leverage arm 121 which itself at one extremity is carried by yoke 122; yoke 122 is carried by an extension 123 of a depending rod 124 of a spring return air operated diaphragm (FIG. 3). Actuation of the air valve 125 thus controls rotation of shaft 119 and the vertical position of latch rods 111 and stop members 105.

In the embodiment described, spring pressure on the spring return air operated diaphragm 125 (FIG. 10B) re tains the latch in locked position; upon application of air pressure, elfected with a manually controlled pushbutton, the system is biased to locking position, as is described hereinafter.

FIGS. 10A and 10B schematically illustrate one arrangement of power supply and control mechanism useful in the operation of the device. The numeral 128 designates a load pushbutton and the numeral 129 a pushbutton for unloading the device. Operation of pushbutton 128 energizes solenoid 13%) which permits supply air to pass two-way valve 131 and supply air to the diaphragm valves 133, 134. Air pressure on the latter valves repositions the valves from the unload position shown in the drawing (see FIG. 9 also) to place the air cylinders 63 in communication with the manually operable three- Way valve 136. This valve 136 is at this time in a condition suitably termed Position, and so designated in the drawing, to permit air of relatively low pressure to pass the three-way valve from the pressure regulator 137 to which regulator the air is supplied from the main line 138. Thus, air enters the air cylinders 63 at the upper end (FIG. 10A) and urges the piston forwardly to the stop members previously described.

Spring pressure retains the stop members positioned downwardly (FIG. 9) until the plunger 140 is manually depressed. Then air is supplied through line 141 to the cylinder to raise the stop members 105 to' unlocking position. Plunger valve normally opens to the atmosphere, removing air pressure from the spring biased diaphragm 142 and permitting the spring 143 to effect lowering of the stops. Accordingly, release or" the manuzally operated plunger restores spring pressure, and the rollers lie on the housing of the bearing.

Freeing of the assembly from the stops by air application to cylinder 125 permits the assembly to advance until the blade is in kiss-contact with the roll.

With the blade so positioned, three-way valve 136 is shifted to load position and full pressure is applied through regulator 144 to the blade and to the backing roll 16 by the blade.

As the air pressure is applied to the upper end (FIG. 10A) of cylinder 63, air is exhausted to the atmosphere through line 102.

When it is desired to unload, it is simply necessary to press the unload pushbutton. This returns valve 131 to the position of the drawing, thereby returning valves 133 and 134 to the drawing (FIG. 10A) position also; air pressure is then applied tothe bottom end (FIG. 10A) of the air cylinders 63 through regulator 146, evacuating air from the upper end of the these cylinders and withdrawing the blade in a positive motion from the backing roll.

Spring pressure is returned to the stop member mechanism when plunger 140 is released; thus the stop members normally lie on the housing and the mechanism simply moves downwardly under spring pressure when the piston retracts, permitting the rollers to drop into place to lock the stop members.

The oscillating mechanism customarily, the paper web being coated is of slightly lesser width than the backing roll. Accordingly, wear of the smoothing device may cause a ridge to occur in the smoothing device at each paper edge if the device is continuously presented in one position to the web. To prevent such ridge formation, it is desirable to oscillate the smoothing device. The suspension system of the assembly and the air cylinder mountings provided for such oscillation of the assembly. Thus, the air cylinders, since they are free to move horizontally, apply the air pressure directionally, that is, generally radially, if desired, re-

gardless of the longitudinal position of the assembly; the pivotal connections of the suspension arms with the assembly permit free longitudinal movement slightly out of a true vertical plane while yet maintaining substantial planar perpendicularity to the longitudinal axis and face of the backing roll.

For the purpose of oscillating the assembly (FIG. 3) a shaft 150 is welded to the rightward securing member 36 or to the carrier itself; the outer extremity of this shaft carries a first universal joint having a yoke 152, and a pin 154 which projects through the yoke arms. Journaled on the pin is a shaft 156 which itself has a second universal joint 157, which shaft is driven in reciprocation as indicated by the arrow by any suitable eccentric. An assembly movement longitudinally of the backing roll (144) of about 1" is provided by the arrangement and is suitable for the purpose.

In the preferred mode of operation of the device thus described, the hanger 89 is adjusted in vertical position to so align the blade with the backing roll that the line of contact will be about below the horizontal (FIG. 2). The adjustment is made by loosening bolts 84 and moving the hanger relative to the bolts in slots 82. Such movement is effected while the hanger rests on the angle iron 86, the adjustment being made by means of bolts 87. With the hanger bolts locked in position, the arms depend almost vertically.

In the blade holder angle, which is the angle between a tangent to the backing roll and the blade holder, the line of contact is initially adjusted by means of the pin in slot arrangement designated at 37, 38, the carrier being tilted relative to the suspension arms by means of nut 50.

Adjustment is made both for the hanger and for the blade holder carrier at each end of the device. The angle at which the blade will contact the tangent to the roll is indicated by the scale 64. Suitably, this angle may be in usual operation about 55.

The coating supply in pan 24 is an aqueous mineral coating composition having the following formulation:

Parts by weight Clay 70 Sodium hexainetaphosphate 0.2 Calcium carbonate Caustic 0.2 Starch 17 Calcium stearate 0.5

Water sufiicient to make 58% solids.

The viscosity of such composition is approximately poises, or about 40 Brookfield at C. with a No. 6 spindle at 100 rpm. By way of specific example, the paper web 13 applied to the inlet side of nip 22 has a basis weight uncoated of about pounds basis weight, being predicated upon 500 sheets 25 x 38". The web is fed to the backing roll at substantially backing roll rotational speed, that is, about 900 f.p.m., the backing roll itself having a diameter of approximately 30 inches. The applicator roll rotates at a less rotational speed than the backing roll and may similarly have a diameter of about 30 inches or may be as small as /3 the backing roll diameter. In practice, a suitable applicator roll speed is 300 surface f.p.m. when the backing roll speed is 900 fpm.

The blade (FIG. 1) is pressured to the backing roll at a pressure of about 3 pounds per lineal inch, although this way may vary between about 1 /2 pounds to 9 pounds per lineal inch.

Under the foregoing conditions, the total coat weight applied to the web may be about 12 pounds per side, it being understood that such webs are normally passed through a second and similar coater. Before passing to the second ceatcr, the web is dried in conventional manner.

In a further embodiment of the device of invention (FIG. 11), the securing plates of the previous embodiment may be eliminated and the angle change mechanism may be effected from overhead. Thus, referring specifically to FIG. 11, the suspension arms depend from a toothed segment 162 which meshes with a gear 164 and is itself pivoted at 166 to a machine frame portion 168. The backing roll 17% is pressured by the blade 172 which is carried in the holder 174. The holder 174 is itself mounted at 176 on a longitudinally extending (not shown) carrier similar to the apparatus described in connection with the previous embodiment. A fixed support 178 pivotally retains at 188 an air cylinder 182. The piston 134 is radially aligned with the radius R of the backing roll. The mount 176 is supported as described in the previous arrangement on universal joints 186, similar joints being provided also on sector 162. In FIG. 11 only one side of the device is illustrated but it will be understood that the opposite sides of the mount 176 would be similarly supported for movement. In FIG. ll force is applied directly radially.

Advantages of the described arrangements include the occupation of a minimum of space which is always a premium factor in the arrangement of paper machinery equipment. Additionally, the universal joints and suspension arms freely supporting the blade holder assembly permit self-adjustment of the assembly and accurate alignment with the backing roll even though the assembly weight may itself be not quite uniform over the assembly length.

The provision of the line of contact parallel with (FIG. 11) or coincident with the pivot axis of the blade holder provides for angle adjustment of the blade relative to the roll tangent while maintaining the line of contact fixed; such provides that the dwell time or peripheral length of the backing roll between the applicator nip and blade nip may be constant regardless of blade angle.

The device of FIG. 11 is advantageous with respect to angular adjustment since the blade angle may be changed while the apparatus is in operation; such may be desirable if the blade Wears, for example. The overhead arrangement and the position of the pivot axis parallel with the line of blade contact and longitudinal axis of the backing roll and in a vertical plane, which includes the line of blade contact, facilitate this angular adjustment without machine stoppage.

Also, the apparatus of FIG. 11 provides for direct radial loading; the apparatus of FIGS. 1 to 3 provides loading which may be very nearly radial; such loading provides that the blade pressure may be very nearly constant despite normal blade wear and small blade angle change.

It is to be noted that the hollow nut and bolt assemblies 34 (FIG. 4) at each end of the device is adapted to receive a small diameter flexible rod which, as already noted hereinbefore, is carried on an edge of a flexible plate element in known manner and may serve as the flexible doctor blade in place of the blade specifically described hereinbefore.

It will be understood that this invention is susceptible to modification in order to adapt to different usages and conditions and, accordingly, it is desired to comprehend such modifications within the invention as may fall within the scope of the appended claims.

What is claimed is:

1. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its longitudinal axis; a longitudinally extending doctor blade holder assembly extending lengthwise with and fronting on the backing roll; and means mounting the blade holder assembly for movement toward and away from the backing roll in a direction transversely to the said longitudinal axis, said means comprising parallel depending swinging support arms, two adjacent each longitudinal end of the assembly, the arms of each end being journaled to the 9 said end and supporting the assembly for swinging movement in said transverse direction.

2. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its longitudinal axis; a longitudinally ext-ending doctor blade holder assembly extending lengthwise with and fronting on the backing roll periphery; means mounting the blade holder assembly for movement toward and away from the backing roll in a direction transverse to the said longitudinal axis, said means comprising parallel depending swinging support arms, two adjacent each longitudinal end of the assembly, the arms of each end being journaled to the said endand supporting the assembly for free swinging movement in said transverse direction; and pivot means defining a pivot axis for the blade holder assembly, said pivot axis extending parallel with said longitudinal axis and lying in a vertical plane which intercepts the backing roll periphery and the blade holder assembly in the forward position of the said assembly in a common line.

3. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its longitudinal axis; a, longitudinally extending doctor blade holder assembly extending lengthwise with and fronting on the backing roll and including a blade holder and a flexible blade; means mounting the blade holder assembly for movement toward and away from the backing roll in a direction transversely to the said longitudinal axis, said means comprising parallel, depending swinging support arms freely journaled on each longitudinal end of the assembly, said blade and backing roll in the advanced position of the assembly defining a line of blade contact with the backing roll; and pivot means defining a pivot axis for the said assembly, said pivot axis being parallel with said line of blade contact and with the said longitudinal backing roll axis, said pivot axis and line of blade contact lying in a common vertical plane.

4. The combination, as claimed in claim 3, and in which the said pivot axis and the said line of blade contact are coincident.

5. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its longitudinal axis; a longitudinally extending doctor blade holder assembly having fixed end panels, said assembly extending lengthwise with and fronting on the backing roll and including a blade holder; means mounting the blade holder pivotally and for movement toward and away from the backing roll in a direction transversely to the said longitudinal axis, said means comprising securing members of the assembly carried by and arranged to overlie the said end panels and also extending longitudinally beyond the backing roll extremities, pivot means retaining the panel and securing member of each end together in cooperable relation, said pivot means also lying beyond the back roll extremities at each assembly end and being disposed toward the backing roll axis, a pin in slot arrangement for pivotal movement of each cooperable panel and securing member relative to each other, said pin in slot arrangement lying opposite said pivot means, means associated with each cooperable securing member and end panel for rotating said assembly to different angular positions and means for locking each cooperable panel and securing plate in adjusted angular position; and parallel, depending, swinging support arms journaled on each securing member being articulated to the securing member retaining said assembly suspended and also restraining a securing member against rotation.

6. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its own longitudinal axis; support means above the backing roll; a longitudinally extending doctor blade holder assembly extending lengthwise with and fronting on the backing roll and suspended for movement toward and away from the backing roll in a direction transversely to the longitudinal axis of the backing roll; parallel, swinging support arms depending from said support means, two on each longitudinal end of the said assembly articulated to the assembly supporting the assembly in suspended position; and means for urging said suspended assembly in the direction of the backing roll to maintain the assembly in engagement with the backing roll under transverse stress, said latter means comprising fluid pressure means journaled to said assembly for free movement longitudinally and transversely of said backing roll.

7. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its own longitudinal axis; support means above the backing roll; a longitudinally extending doctor blade holder assembly extending lengthwise with and fronting on the backing roll and suspended for movement toward and away from the backing roll in a direction transversely to the longitudinal axis of the backing roll; parallel, swinging support arms depending from said support means, two on each longitudinal end of the said assembly articulated to the assembly supporting the assembly in suspended position; and means for urging said suspended assembly in the direction of the backing roll to maintain the assembly in engagement with the backing roll under transverse stress, said latter means comprising a pair of pivots lying in an extension of the radius of the backing roll on each end of the assembly, and a fluid pressure piston-cylinder combination journaled between each pair of said pivots, the pivot of each end which is remote from the backing roll restraining the said pistoncylinder combination from movement as a unit.

8. In combination, in a coating device for paper webs and the like, a backing roll mounted to rotate on its own longitudinal axis; support means above the back roll; a longitudinally extending doctor blade holder assembly extending lengthwise with and fronting on said backing roll suspended for movement toward and away from the said backing roll in a direction transverse to the longitudinal axis of the backing roll; parallel, swinging support arms depending from said support means, two on each longitudinal end of the said assembly articulated to the assembly supporting the assembly in suspended condition; means on each end of the assembly for urging the suspended assembly in the direction of the backing roll to maintain the assembly in engagement with the backing roll under transverse stress, said means comprising fluid pressure cylinders having their pistons journaled on said assembly, and a shiftable, positionable stop member, one in alignment with each piston, lineally aligned abutments of said assembly in the form of a bearing housing for each piston adapted to coact with each piston to assure stopping of said assembly at a predetermined setting in the advance of the assembly to the said backing roll; and means for freeing said stop members simultaneously from said abutments whereby the freed assembly is aligned end to end for movement to the backing roll.

9. A combination as claimed in claim 8 and in which the means for freeing the stop members include a rocker lever pivoted on the frame of the device adjacent each end of the assembly, a support link pivoted on each rocker lever, a swing link pivoted to the other extremity of each support link, a cross-rod carrying the swing links, and means for rotating said cross-rod.

10. Apparatus for coating paper in web form comprising a rotatable roll on which a said web carrying an excess of coating composition travels, a flexible doctor for removing said excess of coating composition from said web, said doctor engaging said web on said backing roll along a line of contact, angle adjustment mechanism including a blade holder for varying the angle at which said flexible doctor contacts said web on said backing roll,

vertically extending suspension means supporting said blade holder for movement toward and away from the said backing roll, segment gear means formed as part of and supporting the suspension means, means including gearing meshed with said segment gear means to move said suspension means to a selected angular position, pivot means supporting said segment gear means and defining a pivot axis about which said segment gear means pivots, said pivot axis extending parallel with and lying in the same vertical plane as said line of Contact, a pair of pivots in alignment with an extension of the radius of the backing roll through said line of Contact, one pair on each end of said blade holder, and a fluid pressure cylinderpiston means supported by each pair of said pivots for urging the blade holder and suspension means toward and away from the circumferential surface of said backing roll.

Refer-eases Cited by the Examiner UNITED STATES PATENTS 1,411,907 4/1922 Brunner 15-256.51 2,910,383 10/1959 Miller et a]. 117102 2,938,810 5/1960 Porfilio et al 117102 3,080,847 3/1963 Justus 118-126 3,113,890 12/1963 Johnson et a1. 118-126 3,158,498 1/1964 Car enter 118 FOREIGN PATENTS 557,051 5/1958 Canada.

CHARLES A. WILLMUTH, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

MORRIS KAPLAN, LEON G. MACHLIN,

Assistant Examiners.

Claims

1. IN COMBINATION, IN A COATING DEVICE FOR PAPER WEBS AND THE LIKE, A BACKING ROLL MOUNTED TO ROTATE ON ITS LONGITUDINAL AXIS, A LONGITUDINALLY EXTENDING DOCTOR BLADE HOLDER ASSEMBLY EXTENDING LENGTHWISE WITH AND FRONTING ON THE BACKING ROLL; AND MEANS MOUNTING THE BLADE HOLDER ASSEMBLY FOR MOVEMENT TOWARD AND AWAY FROM THE BACKING ROLL IN A DIRECTION TRANSVERSELY TO THE SAID LONGITUDINAL AXIS, SAID MEANS COMPRISING PARALLEL DEPENDING SWINGING SUPPORT ARMS, TWO ADJACENT EACH LONGITUDINAL END OF THE ASSEMBLY, THE ARMS OF EACH END BEING JOURNALED TO THE SAID END AND SUPPORTING THE ASSEMBLY FOR SWINGING MOVEMENT IN SAID TRANSVERSE DIRECTION.