US2664792A

US2664792A - Multilength continuous doctor blade

Info

Publication number: US2664792A
Application number: US118150A
Authority: US
Inventors: Ernest P Cook
Original assignee: Brown Co
Current assignee: Brown Co
Priority date: 1949-09-27
Filing date: 1949-09-27
Publication date: 1954-01-05
Anticipated expiration: 1971-01-05

Description

Jan. 5, 1954 E. P. cooK 2,664,792

MULTILENGTH CONTINUOUS DOCTOR BLADE Filed Sept. 27, 1949 4 Sheets-Sheet l j i Q r i E N I 0 l I i I w Q i *3 w w a j Lg m M Q 1 0 v f o o a m ug BY QM/1.52%. 4Z5! 9%:4

HTTOE i EV Jan. 5, 1954 E. P. COOK 2,564,792

MULTILENGTH CONTINUOUS DOCTOR BLADE Filed Sept. 27, 1949 4 Sheets-Sheet 2 IN V EN TOR.

Jan. 5, 1954 E COOK MULTILENGTH CONTINUOUS DOCTOR BLADE 4 Sheets-Sheet 3 Filed Sept. 27. 1949 Jan. 5, 1954 300 MULTILENGTH CONTINUOUS DOCTOR BLADE 4 Sheets-Sheet 4 Filed Sept. 27, 1949 IN V EN TOR.

54nd Pf 1 TTOR/VEV Patented Jan. 5, l 954 UNITED STATES MULTILENGTH CONTINUOUS DOCTOR BLAD Ernest P. Cook, Berlin, N. H., assignor to Brown Company, Berlin, N. H.,

Maine a corporation of Application September 27, 1949, Serial No. 118,150

6 Claims. 1

My invention concerns improved apparatus for removing paper or the like from rolls, as calender rolls, dryer cylinders, etc.

Devices of this character generally comprise a flexible strip of metal referred to in the paper industry as a doctor blade which is held against the roll in position to peel the paper from the roll as the roll revolves. Frequently, the working edge of the blade is so formed as to impart a crimp or crepe to the paper, the crimp or crepe being advantageous, for example, in the case of paper toweling, paper napkins and the like.

I-leretofore, doctor blades have had a length exceeding by only a few inches that of the face of the roll against which they are operated. These blades, which may be either fixed or reciprocat ing, function satisfactorily for a varying period the duration of which depends upon the metal of which the blade is formed, the condition of the roll surface, the speed at which the roll is revolved, and other factors. It then becomes necessary to interrupt production to remove the bur which forms on the edge of the blade. This interruption is manifestly economically undesirable and is particularly serious inthe case of creping blades, since the creping edge is soon lost.

My invention has as its principal object to eliminate these uneconomical interruptions in production.

I accomplish the statedobject through the use of a system of apparatus comprising a doctor blade havinga length substantially exceeding the length of the working portion of the face of the roll and further comprising means for continuously or intermittently moving the blade across such face and means for maintaining the working edge of the blade in substantially optimum condition at all times. The latter means in the preferred construction takes the form of one or more suitably positioned grinding wheels.

I feed the blade from a first reel or drum positioned at one end of the roll and collect or re cover it on a powered second reel at the opposite end of the roll. With this arrangementit is possible to use a greater length of blade than would be the case, for example, should the blade be passed around and moved by frictional engagement or otherwise with pulleys at each end of the roll. Moreover, the arrangement provides for a more positive drive and for better tensioning of the blade.

In my preferred construction, both of the reels are powered to allow for continuous uninterrupted operation. Thus, when the original feed reel is substantially played out, it becomes a collector reel to complete the cycle, the reversal be ing effected automatically by means responsive to the change in the diameter of the coiled blade on the unwinding reel. The blade while engaging the roll is supported in a holder which is continuously urged toward the roll to maintain the blade in operative position.

The apparatus in its preferred construction may further include means for lubricating the blade so that it can be passed more readily through the holder, the lubrication serving incidentally to retard rusting of the blade, and scraper elements mounted to remove any fibrous accumulations from the blade before it is wound on either of the reels.

I shall further describe my invention with the aid of the accompanying drawings illustrating a system of apparatus conforming therewith. In the drawings,

Fig. 1 is a view in elevation showing a dryer roll, partly broken away, and my apparatus at either side thereof;

Fig. 2 is a plan view taken at one end of th roll;

Fig. 3 is an elevation showing parts shown in Fig. 2 and drawn to the same scale;

Fig. 4 is a view on the line 4-4 of Fig. 2;

Fig. 5 is a detail illustrating the operation of one of the elements shown in Fig. 2;

Fig. 6 is a view on line 6-43 of Fig. 1;

Fig. 7 is a detail of the blade holder;

Fig. 8 is another detail showing parts of the blade holder;

Fig. 9 is a viewon line 9 of Fig. 8;

Fig. 10 is an elevation similar to Fig. 8 illustrating a modified form of blade holder;

Fig. 11 is a view on line |l-ll of Fig. l0; and

Fig. 12 is a view on line l2i2 of Fig. 16'.

Referring first particularlyto Figs. 1 and 6, the

dryer roll ill, which may be considered as a Yankee dryer positioned at the discharge of the wet end of a standard paper making machine, is operated at a speed somewhat exceed-- ing the rate of withdrawal of the paper l2 (see Fig. 6) which usually contains 50-60% moisture- The edge of the blade [4 is square or approximately so in order that a crimp will be imparted: to the paper.

The blade M is held in a holder It, shown in vertical section in Fig. 7 (see also Fig. 8), between

plates

18 and 20 connected by rivets 22 which pass through a filler plate 24 on which the blade rides. The slots 23

inthe plates

20 and 24, which are subjected to radiant heat from the roll it, allow these plates to expand at different rates relative to plate is, thus eliminating any tendency of the blade holder unit to distort. Plate i8 is supported and retained in position by members 2t and 28. Leaf springs 30 and 3!, backing the plate is, are secured to the upper part of member 28 by screws 28a. Screws 2% provide for adjustment of the spring pressure applied to the plate. 7

The entire blade holder unit is secured by bolting to a platen 32 supported on and fixed to a shaft 34 journaled in bearings 36. Since the greater part of the weight of the platenlies rearward of the shaft 34 (to the right of theshaft in Fig. 6) the blade M is constantly urged-against the face of the roll. ,Screw mechanisms actuated through knobs 38 and fill provide for horizontal 3 and vertical adjustment, respectively, of the bearings 56. Fluid pressure units 42 can be used to supplement the action of the weighted platen in maintaining the blade against the roll and also provide a means of moving the doctor blade unit away from the roll I when it becomes necessary to change the blade. These units connect to the shaft 54 which extends beyond the bearings 36 through linkages 44 fixed to the ends of the shaft. Like the bearings, they are supported on the frame 46, 45' of the paper machine.

At either side of the machine and supported on a base plate 48, 48' secured to the frame 46, 45' is an assembly comprising an

electric motor

50, 50, speed reducing gears 5| connected to the motor through a flexible coupling 52, 52', an over-running clutch 53, 53', and a reel 54, 54'. The assemblies are seen in p rspective in Fig. 1 as they are mounted on the

plates

48, 48 at a slight angle with reference to the frame of the machine.

Motors 55, 50 are reversible and are under the control of micro-switches 56, 56 (se Fig. 2), the

.microswitch being actuated by the blade I4 after it has been unwound to an extent such that substantially none of it remains wrapped around the .hub of the reel. The end of the blade (see Fig.

4) is secured Within the core 50 by means of a frictional clamp comprising

wedge elements

50 and 52 and an actuating bolt 04. Bolt 64 extends through the reel hub 66, 60' which is keyed on the upper end of the over-running clutch shaft 08, supported by bearings I0, I0.

Extending from the base plate 48, 48' and adjacent the bearing I0, I0 is an adjustable brake 12, I2, the purpose of which will be hereinafter explained. The brake includes a spring component 74 (see Fig. 3) the extent of the compression of which is controlled by a screw element 16. Spring 14 is contained within a cup 18 hearing on a cam member 80 fixed to or integral with an annular shoe 82 which is undersurfaced with a suitable brake lining material 85 and which operates against the top surface of the upper part of the over-running clutch 53.

The brakes I2, I2 are efiective only on olockwise rotation of the reel, the spring 74 on such rotation becomin compressed as the cup 78 is raised by the cam 80.

Inward of each of the reels 54, 54' and in the path of the blade 14 is a grinding wheel 85, 85' powered by a

motor

85a, 85a. Each grinding wheel is pivotally supported on a plate 86, 86' vertically slidable in guideways 88 (see Figs. 2 and 3). Dowel pins 95 and 92 receivable in an aperture in a spacer plate 94 secured to the casing of the motor of the grinding wheel unit provide for locking of the unit in either a horizontal non-operating position, as during changing of the blade, or in an inclined operating position as shown.

Below the plate 06 is a screw jack 56 hand actuable through a crank 98. The sleeve or collar 99 to which the crank is connected is fixedly secured to or made integral with a larger collar I00 thereabove. Collar I00 is held fixed against vertical movement by upper and lower bearing members, not shown. Surrounding the collar is a ratchet wheel l0! controlled by a spring-actuated pawl I02 connected by a bell crank I03 to a linkage I04 and by a second spring-actuated pawl I02a supported by a fixed pivot mounted on one of the guideways 88. Linkage I04 at its end opposite the pawl I02 is joined to a second bell .crank I05. Elements I00 and I01, pivoted to the bell crank I05 at the free end thereof, are connected by a spring I00 and are capable only of inward movement. These elements coact with a pin I09 on the undersurface of the reel as subsequently explained.

Disposed between each grinding unit and the reel on the same side of the machine is a pair of guide rollers II2 for aligning the doctor blade I4 with the doctor blade holder unit and a pair of grooved rollers H4. The upper of the rollers H4 is spring loaded downwards (spring not shown), while the lower is fixed in position. These rollers provide a means of holding the doctor blade in proper position for grinding.

Beyond the grinding wheel and in the path of the blade is a scraper element H6 and a felt lubricator I I8 supplied with oil from a container I20 fastened to the upper portion of the frame 45. The scraper element and lubricator are supported by a bracket I22 fixed to the platen 32.

Operation In describing the operation of the apparatus it will be assumed that the blade I4 is moving toward the right, reel 54 thus being the winding reel and reel 54' the unwinding reel. As the blade leaves the dryer roll I0 at the right it passes sequentially through the lubricator H8 and the cleaner or scraper H6. The latter, it should be noted, is effective only when the blade is traveling toward the reel 54. The blade next passes under the grinding wheel 85, which is in grinding contact with the blade, and thence between the rollers of the roller pairs H4 and H2 to the reel. At this stage the over-running clutch 53 is engaged and the brake 12 is off.

When the reel 54' has played out, the corresponding micro-switch is actuated to reverse both motors. Reel 54 now becomes the winding reel and reel 54 the unwinding reel. The purpose of reversing the motor powering the reel 55 i: eliminate the extra pull on the doctor blade which would otherwise be required to rotate the speed reducer and motor. In reverse direction the motor operates at a speed greater than its speed when reel 54 is serving as the winding reel and the upper portion of the over-running clutch 53 is disengaged from the lower portion. Brake 12, which becomes immediately effective when the motors are reversed, provides the retarding force necessary to prevent the doctor blade from becoming too loose on the unwinding reel.

On the change in the direction of rotation of reel 54, pin I 09 on the undersurface of the reel strikes element I06, pivoted on the bell crank I05 (see Figs. 2 and 3), causing retraction of the pawl I02 so that on the next reversal of the reel the pawl will properly position the grinding wheel against the doctor blade. Pawl I02a serves to prevent rotation of the ratchet wheel IOI as pawl I02 is retracted. The distance through which the pawl I02 is adapted to move the grinding wheel is slight, being only ufiicient to compensate for the wear incident to the preceding grinding.

As reel 54 plays out the blade draws progressively closer to the micro-switch 56 (see Fig. 2) until finally on near exhaustion of the reel the blade contacts the switch, again reversing the motors to start a new cycle. With the reel rotating counterclockwise, pin I09 strikes element It? (see Fig. 5) after previously striking element I06 which yields to the pin, and pawl I02 forces the ratchet wheel IOI to rotate, thereby lowering the grinding wheel into grinding contact with the edge of the doctor blade.

It should be noted that while the shank of the screw 96 lies well forward of the plate 98, the head of the screw is extended and fastened to the bottom of the plate.

During stripping of the paper from the roll ii and impartation of the crimp, the blade i l, a.- previously explained, is held by the stationary holder Hi, the lower edge of the blade riding on the upper edge of the filler plate 24. In the case of the modified construction shown in Figs. -12,

the blade rides on anti-friction elements, shown as rollers I24v supported between plate i925 a backing plate I28 which is joined to plate by rivets I30 beneath the rollers. The slots in the plates through which the roller shafts pass are made oversize to allow for heat expansion.

From the foregoing it is believed apparent that my invention, by eliminating the frequent interruptions heretofore necessary in order to sharpen or replace the dulled blade, markedly speeds up production and allows for many operating economies.

Many changes and modifications other than those which have been indicated may, of course, be made in the apparatus disclosed without departing from the spirit and scope of the invention.

I claim:

1. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade of an indeterminate length exceeding the length of the roll, a weighted holder for the blade serving to automatically maintain the blade in operative position against the face of the roll and to compensate for reduction in the width of the blade due to wear and means for drawing the blade through the holder including a reel at either end of the roll in which one of the ends of the blade is secured, each of said reels being powered by reversible means connected to the reel through clutch means adapted for automatic disengagement on winding rotation of the opposite reel.

2. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade of an indeterminate length exceeding the length of the roll, a weighted holder for the blade serving to automatically maintain the blade in operative position against the face of the roll and to compensate for reduction in the width of the blade due to wear, means for drawing the blade through the holder including a reel at either end of the roll in which one of the ends of the blade is secured, each of said reels being powered by reversible means connected to the reel through clutch means adapted for automatic disengagement on winding rotation of the opposite reel, and blade grinding means positioned mediate at least one of the reels and the corresponding end of the roll.

3. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade of an indeterminate length exceeding the length of the roll, a weighted holder for the blade serving to automatically maintain the blade in operative position against the face of the roll and to compensate for reduction in the width of the blade due to wear, means for drawing the blade through the holder including a reel at either end of the roll in which one of the ends of the blade is secured, each of said reels being powered by reversible means connected to the reel through clutch means adapted for automatic disengagement on winding rota- 0 tion of the opposite reel, and scraper means mediate each reel and the corresponding end of the roll serving to clean the blade prior to the winding thereof on the reel.

4. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade of an indeterminate length exceeding the length of the roll, a weighted holder for the blade serving to automatically maintain the blade in operative position against the face of the roll and to compensate reduction in the width of the blade due to wear, means for drawing the blade through the holder including a reel at either end of the roll which one of the ends of the blade is secured, each of said reels being powered by reversible m ans connected to the reel through clutch means adapted for automatic disengagement on winding rotation of the opposite reel, and blade lubricating means positioned mediate at least one of the reels and the corresponding end of the roll.

5. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade of an indeterminate length exceeding the length of the roll, a weighted holder for the blade serving to automatically maintain the blade in operative position against the face of the roll and to compensate for reduction in the width of the blade due to wear, means for drawing the blade through the holder including a reel at either end of the roll in which one of the ends of the blade is secured, each of said reels being powered by reversible means connected to the reel through clutch means adapted for automatic disengagement on winding rotation of the opposite reel, blade grinding means mediate each reel and the corresponding end of the roll automatically actuated on winding rotation of the reel, a scraper element mediate each grinding means and the end of the roll for cleaning the blade prior to winding thereof on the corresponding reel and blade lubricating means positioned mediate at least one of the scraper elements and the corresponding end of the roll.

6. Apparatus for removing paper from a revolving roll to which it tends to adhere, comprising a flexible doctor blade having a length exceeding the length of that portion of the face of the roll contacted by the paper or the like, a holder through which the blade is passed, reel means at one end of the roll for feeding the blade to or receiving the blade from the holder, reversible means for powering said reel, an overrunning clutch mediate said reel and said reversible powering means and a brake coactively associated with the driven portion of said clutch tending to retard rotation of the reel on unwinding rotation thereof to an extent precluding loosening of the blade on the reel.

ERNEST P. COOK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,057,073 Mertens Mar. 25, 1913 2,148,455 Golber et al Feb. 28, 1939 2,300,908 Broughton Nov. 3, 1942 2,417,796 Happ Mar. 18, 1947 2,487,409 Baker Nov. 8, 1949 2,494,334 Dorst Jan. 10, 1950 2,567,967 Rowe Sept, 18, 1951