US2417796A

US2417796A - Electrical system for doctor blade control in paper making machines

Info

Publication number: US2417796A
Application number: US479635A
Authority: US
Inventors: Happ Edwin Lewis
Original assignee: Ecusta Paper Corp
Current assignee: Ecusta Paper Corp
Priority date: 1943-03-18
Filing date: 1943-03-18
Publication date: 1947-03-18
Anticipated expiration: 1964-03-18

Description

E. HAPP 7,79

ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL IN PAPER MAKING MACHINES March 18, 1947.

- 2 Sheets-Sheet 1' Filed March 18, 1943 3nventor: ups-Mm Edna in, Ie W PM Z is Gttorneg,

March 18, 1947. E. HAPP ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL IN PAPER MAKING MACHINES 2 Sheets-Sheet 2 'Filed March 18, 1943 3nventor;

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Patented Mar. 18, 1947 ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL IN PAPER MAKING MACHINES Edwin Lewis Happ, Brevard, N. 0., asslgnor to Ecusta Paper Corporation, a corporation of Delaware Application March 18, 1943, Serial No. 479,635

2 Claims.

This invention relates to paper making machines and has to do more particularly with the operating control of the doctor blade of such machines.

In paper making machines there is usually cooperatively associated with the dryer cylinder, a bladed device known in the art as a doctor. The blade member of this device is usually maintained in edge contact with the circumferential face of the rotating dryer cylinder so as to keep the latter clean by removing therefrom dust, fibers and other foreign matter or broken paper that might adhere thereto.

To prevent scratching or scoring the surface annularly of the dryer cylinder provision is made for constantly reciprocating the doctor blade longitudinally during the time the cylinder is rotating, but unless reciprocation of the doctor blade is stopped when rotation of the cylinder ceases the edge of the blade is liable to mar the face of the cylinder with detrimental scratches or scores transversely thereof.

Attempts have been made by the use of various mechanical contrivances for a timed starting and stopping of reciprocation of the doctor blade upon the starting and stopping of dryer cylinder rotation. Such mechanisms are not only more or less intricate and expensive to produce and maintain in working condition, but it has been found difficult (if at all possible) to automatically start and stop reciprocatory operation of the doctor blade simultaneously with the starting and stopping of rotation of the dryer cylinder or at least at the proper time to prevent marring of the surface of the dryer cylinder.

The present invention has been brought about for the attainment of a simplified and economical yet better and more positive and accurately timed control of the doctor blade reciprocation. This is accomplished by the utilization of an instantly operative electrical system in elimination of mechanical complication but in a direct and practical, cooperative controlling relation between the driving means of the dryer cylinder and the motive means of the doctor device.

A practical and non-limiting exemplification of the present invention is set forth in the following description in conjunction with the accompanying illustrative drawings, in which,

Fig. 1 is a view, more or less fragmentary and schematic, showing a dryer cylinder, finished paper roll and intermediate idler guide roll of a conventional paper making machine in end elevation, and a portion of the machine frame broon the roll l5.

ken away to show the doctor blade in edge contact with the dryer'cylinder;

Fig. 2 is a more or less fragmentary view, at a right angle to that of Fig. 1, of the machine in the region of the dryer cylinder and showing in more detail the doctor device and its operating means, together with the electrical control provision for said operating means;

Fig. 3 is top plan view of the electrical switch unit with the cover removed from the housing; and

Fig. 4 is a section on the line 44 of Fig. 3, with the cover in place on the housing.

Referring now to the drawings in detail, the numeral designates the portion of the main frame of the machine on which the dryer cylinder H is rotatably mounted, as at l2. The paper web 13 as preformed in the machine travels over the cylinder II and is thus dried in the usual manner, whence it passes under an idler guide roller l4 and is then taken up on the finished paper roll l (see Fig. 1). In some machines the dried paper is passed through a calendering medium or otherwise treated before it is wound Such treatment of the paper after leaving the dryer cylinder, however, has

nothing to do with the present invention. Hence, no detailed description or illustration of the same is here given.

For purposes of conventional illustration the dryer cylinder H (see Fig. 2) is provided with a master gear 16 on its shaft. This gear I6 is in mesh with an idler pinion I! which, in turn, is in mesh with a driving pinion l8 fixed on a power shaft IS. The shaft I9 is journalled at one end in a bearing 20 on the adjacent main frame member Ill, and at its opposite end is journalled, as at 2!, on an outer auxiliary frame member 22. As shown, the power shaft I9 is provided with a driving pulley of the conical type 23, which, in practice, is belted to a similar but reversely disposed driving pulley (not shown) at the source of power so that by shifting the belt on the pulleys the dryer cylinder may be rotated at different speeds in the conventional manner.

By the gear arrangement shown the dryer cylinder I I is rotated in the same direction but at a slower speed than the power shaft I9, and this difference in speed of rotation of cylinder and shaft makes for ideal adaptability of the doctor reciprocation control means of the present invention but without absolute essentiality of such speed difference.

The illustrated doctor device comprises an elongated body member of angle iron section, one

plate portion 24 of which carries the blade member 25. As conventionally shown in Figs. 1 and 2, the attachment of the blade member 25 to the body plate 24 is with a reinforcing strip 25. At the opposite ends of the body plate 24 are projecting, axially aligned, supporting bars 21, of round section. These projected bars ride on round-grooved rollers 28 which are journalled in bearing elements 29 secured on supporting brackets 30 that are attached to the adjacent main frame members H), as more clearly shown in Fi 2.

As supported on the rollers 28 the doctor device is reciprocable longitudinally of the dryer cylinder l0, and as the projected end-bars 21 are rotatable as well as longitudinally movable on the grooved supporting rollers 28, said bars serve as trunnion's whereby the doctor device is rockable thereon. In this way the device is swingable about the axis of the bars 21 in order to move the blade member 25 towards and away from the dryer cylinder l, at will.

The relative position and distance of the axis of the supported end-bars 21 of the doctor device from the dryer cylinder II, with the preponderance of weight below the axis, is such that, normally, the outer edge portion of the blade 25 is maintained in contact with the circumferential face of the cylinder. However, if it is desired to move the blade 25 out of contact with the cylinder it is only necessary to operate a cam 3| that is provided for the purpose.

As shown, the doctor device has a rigid downwardly extending tail-piece 32 adjacent the lower end of which is the cam 3|. The cam 3| is normally just clear of the tailpiece 32, it being rotatably mounted in a bearing bracket 33 depending from the adjacent bracket member 30 and having an operating handle 34 that hangs down from the bearing bracket 33 and thus holds the cam in a normally neutral position.

To disengage the doctor blade 25 from the dryer cylinder II the handle 34 is swung upwardly to move the high portion of the cam against the tail-piece 32. This may be done either while the doctor device is at rest or during reciprocation thereof, as the tail-piece 32 is of a width, commensurate with the length of stroke of the reciprocating doctor member, for the tail-piece to remain in contact with the cam 3| while the cam is set to tilt the blade 25 away from the dryer cylinder.

Any suitable motive element may be provided for operating the doctor device. In the illustrative embodiment of the invention a conventional compressed air type of motor 35 is attached to the underside of the lower wing 38 of the rightangular body member of the doctor device (see Fig. 1). Suflice it to say that this type of motor has a reciprocatory piston (not shown) the stem of which protrudes through and beyond the end of the body clinder and is attached at its outer end to a thrust-bar 31 positioned on a supplemental angle bracket 38 that is mounted on the adjacent main bracket member 30 (see Fig. 2). By this provision and arrangement the reciprocation of the motor piston causes a corresponding movement of the doctor device. Sufiice it to further state while the thrust-bar 31 is normally stationary and firmly supported during the reciprocatory operation of the doctor device, provision is made, as by a conventional slot-and-bolt mounting (see Fig. 1), for a compensating rocking and lengthwise sliding movement of said bar on its support when the doctor device is rocked on its supporting end bars 21 to move the blade 25 into and out of contact with the dryer cylinder.

Compressed air for operating the motor 35 is supplied from the source (not shown) through a pipe 39 leading into a conventional unitary assembly of an air filter 40, pressure regulator 4| and lubricator 42, which parts may be mounted stationarily on any convenient part of the machine frame, with a flexible hose 43 connecting the lubricator element 42 to the intake of the motor 35 for supplying the compressed air and a proportionate amount of lubricant therewith to the motor.

All of the foregoing described parts of the paper making machine and appurtenances are conventional, and, per se, do not enter into the present invention other than incidentally in illustration of relative association of the parts and elucidation in the specification and claims.

For the purposes of the present invention the air supply pipe 33 is provided with a. self-closing valve 44, conventionally indicated in Fig. 2. Suflice it to say that, for example, this valve has a reciprocatory stem 45 attached to the core of a conventional solenoid 46 so that, when the magnet coil of the solenoid is energized, the stem 45 is thereby attracted and moved to open the valve 44 to supply the compressed air to the motor 35.

The solenoid 45 is in an electrical circuit 4! from any suitable source of electrical energy, usually volt current supply. As diagrammatically illustrated the source is conventionally indicated as at supply 43, but the same may be otherwise indicated. This circuit is normally broken except during the time the dryer cylinder ll of the paper making machine is rotating and it includes a switch in cooperative relation to the driving means of the dryer cylinder whereby to automatically close the circu't when the cylinder begins to rotate and break the circuit when rotation ceases.

The illustrated switch, designated generally by the numeral 49, is directly associated with the end of the power shaft I9 of the machine. As shown more clearly in Figs. 3 and 4, the switch unit comprises a housing in which two interfiitting rotatable members 50, 5|, are located. The member 50 is cupped with a cylindrical collar portion and the other member 5| is in the form of a plain cylindrical disk of such diameter that it fits peripherally rather snugly into the collar portion of the member 50 so that, by frictional contact between the adjacent circular surfaces, the rotating of one member rotates the other member unless held by some resistance or reversed by a force sufiicient to overcome the friction between the members.

The member 5| (the driver) has an axial stubshaft 52 journalled in a bearing opening in the switch housing. The stub-shaft has a bifurcated cross-head 53 fixed on its outer end. The parallel forks of the cross-head are located in the path of a radial driving arm 54 fixed on the end of the power shaft l9. Thus, when the shaft I3 is rotated the driving arm 54 engages one of the forks of the cross-head 53 and the switch member 5| is thereby rotated in the same direction. At the same time, rotation is imparted to the companion switch member 50 until arrested as will now be described.

The rotatable switch member 53 carries on its periphery a longitudinally extending contact arm 55 which is normally held in a neutral position by a. pair of opposed equalizer springs 56. In its neutral position the contact arm 55 is disposed in spaced relation midway between two opposed pairs of circuit terminal contacts 51, 58, respectively. The contacts 51, 58, are shown conventionally as spaced apart and insulated from the switch housing, and the contact arm 55 is conventionally provided with spanner contacts 59, 60, on opposite sides thereof and insulated there'- from, whereby to engage and electrically connect a pair of the contacts 51 or 58, according to which lateral direction the contact arm 55 is moved.

For the purpose of illustrating the present invention as applied to a machine in which the working rotation of the cylinder or drum against which the doctor device bears is in one direction, only one pair of the switch contacts 51 are used as part of the solenoid circuit 41 as indicated by the pair of wires 41A and 41B of the diagram in Fig. 2 and also as indicated in the views of the switch unit in Figs. 3 and 4.

When the switchmember 50 is arrested in its rotation by the engagement of the spanner contact 59 with the pair of terminal contacts 51 during the operation of the machine, the companion member 5| continues to rotate with th power shaft l9. For this reason the lower portions of the two members 50, 5|, are immersed in a heavy oil contained in the housing as indicated at 6| in Fig. 4. The oil thus provided, not only lubricates the members 50, 5|, where the rubbing occurs between them, but the viscosity of the oil used causes a substantial dragging effect of the rotating driver member 5| upon the companion member 50 which carries the contact arm 55. Said member 50 is thus rotated between the limits of approximately 18 degrees and the contact arm 55 is thereby held with its spanner contact 59 in steady contact with the pair of terminal contacts 51 until such time that rotation of the driver member 5| is stopped. When rotation of the member 5| ceases, even though the driving arm 54 on the power shaft |9 still be against one of the forks of the bifurcated cross-head 53 and thus prevent rotation of the member 5| in that direction, the strength of the equalizer springs 58 is ample to force rotation of the companion member 50 and thus instantly return the contact arm 55 to its centralized neutral position between and out of contact with both pairs of circuit terminal contacts 51, 58.

Instantly, as the switch unit 49 operates to close the circuit 41, the solenoid 45 becomes energized and thus automatically efiects the opening of the compressed air supply valve 44 and the doctor device is forthwith reciprocated. At approximately the same time, the dryer cylinder II has started to rotate because of the ratio of its driving gears 6, 1 and I8 and by virtue of which the power shaft IS in motion has made a certain number of revolutions sufiicient for the driven switch driver member 5| to have caused rotation of the companion switch member 50 and thereby eifected the closing of the solenoid circuit. Just as instantaneously, the solenoid circuit is broken when rotation of the power shaft l9 ceases. Thus, the self-closing valve 44 immediately functions to shut off the compressed air supply to the motor 35 so that operation 01' the doctor device ceases substantially at the moment rotation of a normally open switch member arranged in re- 1 lation to the rotating means for said roll for closing upon rotation of the roll, and an electric circuit including the starting and stopping means for said doctor motive element and said switch member, said electric circuit being connected to actuate said starting and stopping means to starting position when said switch member is closed, whereby back and forth movement of said doctor is automatically effected constantly during rotation of said roll at a speed independent of the rotating speed of the roll and movement of said doctor is automatically stopped when rotation of said roll ceases thereby avoiding scoring of said roll by said doctor.

2. In a paper making machine having a roll for conveying the paper web and means for rotating said roll, a doctor blade associated with said roll, an air motor for moving said doctor back and forth transversely of the paper travel and in contact with said roll constantly during rotation of the roll and at a speed independent of the rotating speed of the roll, an electrically actuated valve element for stopping and starting said doctor motive element, said valve element being biased in stopping position, a normally open switch member arranged in relation to the rotating means for said roll for closing upon rotation REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 2,300,908 Broughton Nov. 3, 1942 1,644,917 Frossard et a1. Oct. 11, 1927 2,058,369 Taylor Oct. 20, 1936 1,861,245 Smith May 31, 1932 1,482,167 Varley L Jan. 29, 1924 2,232,752 Wilson Feb. 25, 1941 1,618,146 Buel Feb. 15, 1927