US3078021A

US3078021A - Apparatus for automatic centering of strips

Info

Publication number: US3078021A
Application number: US103392A
Authority: US
Inventors: William K Crownfield; Hans W Sachs; Charles W Fromm
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1961-04-17
Filing date: 1961-04-17
Publication date: 1963-02-19
Anticipated expiration: 1980-02-19

Description

Feb. 19, 1963 w. K cRowNFlELD ETAL 3,073g021 APPARATUS FoRi AUTOMATIC CENTERING oF STRIPS Filed April 1T',` Igel'l {Sheets-Sheet 1 Fb. 19, 1963 w. K. cRowNF'lELD ETAL 3,078,021

APPARATUS FOR AUTOMATIC CENTERING oF STRIPS Filed April 17, '1961 2 Sheets-Sheet 2' FIG. 5 V

Unite States Patent M 3 @78,021 APPARATUS FR U'MATlC CENTERlNG F STRPS Wiiiiam K. Crownfield, New Brunswick, NJ., Hans W. Sachs, Binghamton, NSY., and Charles W. Fromm, Teaneck, NJ., assignors to Sperry Rand Corporation, New York, NX., a corporation oit Delaware Filed Apr. 17, 1961, Ser. No. 103,392

1G Claims. (Cl. 22d- 21) This invention relates to an improvement in strip or web feeding apparatus and more particularly to the automatic centering and aligning of rapidly fed endless sheets `of thin material such as paper, ribbon or strip sheet metal.

While this device is developed for adaptation to Strip feed mechanisms it can readily be applied to a motion picture or microfilm processing apparatus wherein successive stages of development and drying necessitate continuous rapid lm travel over a number of rollers.

During the course of lm strip processing it is necessary to feed the developed wet lrn into a drying chamber. However, prior to its entry into the dryer, it has been found advantageous to have the greater proportion of water shed from the iilm. This is presently being accomplished by the addition of rubber blades over which the lrn is forced, air blasts or jets against the moving strand, or Sponges over which the strand is pulled. The most etective application is a pair of wringer rollers, preferably rubber surfaced, which, forced against one another diametrically squeeze all excess water from the strip as it passes therebetween. Although roller squeegees have proven very efficient there has been a major drawback in applying them to film strand drying. The full benets of roller squeegee can only be obtained by applying pressure to the rollers as they are urged toward each other. Because of inconsistency inherent in feed and take up rollers and in stack dimensions it is almost impossible to prevent a strand from walking off roller centers. The reasons for oft tracking are manifold and varied in that the rollers might be axially misaligned, the covering may vary in thickness or elasticity or may be inconsistent diametrically, the strand may be warped, longitudinally unequal in length, and the splices connecting the two ends of subsequent ribbons may be irregularly placed.

Corrective measures have been developed employing elaborate hydraulic, pneumatic or electric controls and power sources to shift the rollers for effecting a counter compensating or realigning and recentering action on the strand.

It is an object of the invention to provide a strip apparatus with a roller squeegee for removal of surface water from the strand or web.

lt is another object of the invention to provide a strip apparatus with means for automatically realigning and recentering the strand which has walked off center.

It is a further object of the invention to provide a strip apparatus with a tiltable squeegee unit for simultaneously shedding excess water from and effecting a distinct counter action or center restoring force upon the ofi tracking strip.

These and other objects will be more apparent after reference is had to the following description and to the drawings, inthe latter of which:

FIG. 1 is a view in side elevation of the squeegee device as applied to a lm processor.

FIG. 2 is atop plan view of the squeegee device,

FIG. 3 is a longitudinal view in cross section taken on the line 3-3 of FIG. 2.

FIG. 4 is a transverse section taken on the line 4--4 of FIG. l,

Bl Patented Feb. i9, i953 FIG. 5 is a view similar to FIG. 4 with certain parts in moved position,

` FIG. 6 is a diagrammatic view illustrating the novel strand realigning feature,

FIG. 7 is an elevational view of a modified embodiment of this device,

FIG. 8 is an isometric view of a further modified embodiment using the apparatus as a sensing unit to convey tracking correction signals to rollers between which heavy, wide strip stock is fed,

FIG. 9 is a plan view showing the directions of movement of the correction roller, and

FlG. 10 is a cross section taken -on line 1li-10 of FIG. 9.

The wringer device, generally designated as 19, can be seen as operatively applied to a film processing apparatus, FIGS. 1 and 2, including a developing receptacle 1l.. A roller 12 feeds a lm strand F from the receptacle vertically toward a second roller 12 on' the drying area 13, a horizontal platform 14 of which, has said wringer 1t) mounted thereon situating the device substantially intermediate the

rollers

12 and 12.

A base member 15 of the wringer device has mounted to its underside a pivoting means 16. For illustrative purposes the pivoting means is represented by a hinge comprising a wing 17 secured to the underside of the base member 15, and another wing 13 secured to the pla-tform 14. A vertically depending tab 20, integral with the hinge stud or pin 21, is secured to an end wall of the dryer 13 at right angles to the platform. It is obvious that this construction permits the -base member to tilt either to the left or right of the horizontal over the fixed center stud 21 of the hinge 16. Further, any well known tilting arrangement such as gimbals or a ball and socket combination may be applied to accomplish this action.

Vertical walls 2.2 extend upward from each longitudinal extremity of the base 15 and carry rigidly secured thereto side walls 23, substantially of triangular shape, having the hypotenuse facing upward. The rear or right angle ends are bridged by a frame member 24, liaps 2S, of which, are welded or otherwise secured to the walls 23.

A rocker 26 is composed of vertical plates or legs 27, each plate being positioned substantially adjacent and inside a side wall 23. A central cross web 28 is welded or otherwise secured by iianges to the legs 27, the upper edges of said legs being shaped to form inclines angularly similar to and extending upward and beyond the wall inclines. The rocker 26 carries, fixed in the right angle corners of plates 27, an axle 311, extending beyond both plates, and loosely journalled in the side walls 23. The upper apexes 31 of plates 27 have journalled therein the ends of the transverse shaft 32 of a rubber covered roller 33. Adjacent said roller 33 and substantially on the same diametral plane therewith is a second rubber covered roller 34 on a shaft 35, journalled in the apexes 36 of walls 23.

In order to assure constant pressured relationship between the peripheries of

rollers

33 and 34 as well as having the degree of pressure subject to regulation, a spring urged contact regulator ttl is provided toward the end of base member 15 opposed to the roller end. The rocker bridge 23 extends rearwardly as a horizontal apron 41 to which is welded a lug 42 acting as additional bearing for a vertically depending screw threaded pin 43, peened or otherwise secured in the tapped hole in apron 41. A knurled nut 44 threaded on pin 43, bears against a compression spring 45 which is disposed about the pin 43 and rests on the base member 15, the pin in turn extending freely through a large hole in said base member. The spring 45 normally under compression will force the rocker roller k33, about pivot Sti, to press. against roller 3d. It is obvious that as the thickness of material to be forced between the rollers increases or decreases, the roller pressure can be regulated by increasing or decreasing the operation length of the spring thereby relatively regulating the presure of the roller against the strip.

A lockout latch 45, pivotally secured as at 47 to a bracket 43, fast on base member 35, has a nose protruding through an opening Etl in the bridge 28. Bracket 4S is so placed, FIG. l, with respect to the hole in the bridge that the latch normally stands at an angle. Obviously, if the rocker 2S is pushed down against the spring tension to free a strip from between the rollers the latch will fall by gravity causing the nose to engage the rim of the hole 50 thereby locking rocker roller 33 away from roller 34 until necessary manual adjustments to or replacements of a web or strip have been completed.

To prevent excessive tilting of the whole unit about the center pin 2i which can result from irregular feed speeds causing the strip to pull and jerk, resilient cushioning means such as sponge rubber blocks 5l, FIG. l and 4, can be used. t is, however, essential that the cushioning ortilt retarding means is carefully proportioned to the application so that the counter action will not interfere with the interplay of forces upon which the device depends for proper function.

The ability and purpose of this device to recenter oit tracking strip or web can best be understood if reference is made to FIGS. 5 and 6. In reality the tilting or teetering, though always existent, is virtually indiscernible to an observer since the tilt caused by strand displacement and the corrective tilt are almost simultaneous; the least misalignment o the strand is momentarily corrected. It must be noted, therefore, that for illustrative purposes only are the movements of the related members shown exaggerated.

FIG. 6 shows a linear development of a roller circumference marked oi from 0 to 360. Let it be assurned that a strand F, tracking oh. center, has walked to the right to an arbitrary point a on a contact line A of the roller periphery. The displacement of the strand from the center represents mechanically, the leverage by virtue of which the strand tension acts or pulls on the device to cause tilting. This displacement causes an unbalance of moments about pivot 2l since the strand has sufficiently overcome the inertia of the device and the friction of the pivot resulting in a counterclockwise movement of the rollers. It has been found that the side of the rollers to which the strand tends to off track always will follow the strand, said rollers rocking about the pivot. FIG. 6 illustrates, by angle X, the displacement of the strand relative to the rollers from which point the strand must be forced to return-to the tracking center. It is well known that rollers of identical diameters exert peripheral pressure equally throughout the width of a strand passing therebetween. Since no contact slippage exists there is a constant tendency to retain or restorethe strand center perpendicular to the roller axes. The rollers, presumably articulate by virtue of pivot 21, and tending to align the strandcentrally and perpendicularly, exert more pressure on the left edge of the continuously moving strand. The strand will be forced to walk to the left resulting in the rollers immediately tilting in an opposed or clockwise direction. As the roller turns throughsuccessive small angles, points b on thecenter line of the strand intersect the lines of contact B on the roller periphery. Note that the strand points b are gradually appreaching the roller tracking center as the angles of separation diminish. When the strand finally arrives at point c, the true tracking center, the pull is directly in line with pivot 2i resulting in horizontal stabilization of the rollers, as shown in phantom `in FIG. 5, and perfect perpendicular alignment of strand with the rollers, horizontal contact line C.

In FIGS. 1 4, a squeegee wringer has been employed to illustrate the strand recentering principle of this iuvention. It is to be noted that an additional problem must be considered here in that effective squeegee pressure must be exerted on the wet ilm to squeeze off the surface water in addition to controlling the tension on the film to produce the desired interplay between strand and roller.

Other adaptations are possible in which dry strip materials such as ribbon, paper or magnetic tape, or strip metal can be fed between rollers wherein only the tension pressure of the strip need be considered.

For example, FiG. 7 illustrates the device adapted to be used with light weight wide strip such as manifolding ledger or newspaper stock. Frame 55 supports a horizontal shaft 53. A second frame 57, the end walls of which are -situated inwardly of the frame 55 walls, carries shaft 56 parallel to shaft SS. Because of the extreme widths involved and since the device is designed essentially for dry stock feeding, rollers d@ and 61 on shafts 56 and 5S, respectively, cover only the extreme ends of the shafts leaving the central portions free. Frame 57, similar to the heretofore described preferred form, is resiliently urged toward frame 5S to insure evenly distributed peripheral pressure of the engaging rollers on the strand F passing therebetween.

It has been found, in apparatus designed to feed heavy stock such as metal in strip or endless sheet form, that cumbersome rollers, necessary in conveying heavy strip of this type, cannot in themselves be utilized to successfully correct odi tracking. In FIGS. 8 and 9 a modified version of the device is employed as a sensing unit in such apparatus. A strip centering device 65 substantially as the preferred embodiment described is tiltably supported at 66 below a large roller 67 controlled for reciprocation over which a strand F is fed after having passed between a pair of

sensing rollers

68 and 70, similar in construction and operation asirollers 33 and 34.

Various means can be employed to effect reciprocation of roller 67, for example, balance can be achieved by suitably situated pneumatic jacks and pumps or by leverage operated by cams or gearing. For illustration purposes this invention employs an electro-mechanical system 7l wherein a vertically depending rod 72, on horizontal plate 73, extending from one side of the frame of the sensing unit 65, carries a horizontal resilient member '72 which in turn is connected to the toggle arm of a three way switch 74. Leads and 76 connect poles 77 and 7S, respectively, of said switch to terminals on a reversing motor Si), mounted in close proximity to the roller 67. A third lead S1 connects the motor with the negative line of the power source and a positive source lead 82 is connected to the switch arm S3.

A long shaft $4 extends from the motor Si) having the opposite end screw threaded into a block 8S pivotally mounted to the under side of the yoke 8d, the roller shaft S7 being journalled in the vertical arms S8. The yoke is pivoted for horizontal oscillation on a vertical pin 9i) intermediate its arms 8S. As the screw rotates by energizing motor Sti, the block SS and the integral yoke will swing slightly to the left or right around pivot pin 90.

In operation, for example if the tilt is to the left, that ,is to saythe pivot 65 turns clockwise lifting the left end of the sensing unit, arrow Z, the rod at 72 will force the Switch arm S3 to Contact terminal 78 closing a circuit and .driving the motor 3@ in a Forward direction. The roller 67, turned to a position as shown in phantom in FIG. 9, will be drawn back to the center by virtue of the block S5 being pulled by the clockwise rotation of shaft 84. As soon as true center is attained the plate 67 will have been lifted to the horizontal and the switch arm will have broken contact with point 7S and be at Off position, thereby stopping the motor and subsequent tilting action of the roller. If the kstrip ofi tracks to the right the plate 73 on the unit will be lifted pulling the switch arm to engage contact 77, energizing the motor but in Reverse direction eiecting a counter clockwise rotation to roller 67 until the proper balance and str ip realignment are again reestablished; for the switch will drop to Off position halting the motors energization.

While the principles of this invention have been described in connection with specific apparatus, it 1s to be clearly understood that this description is made only by way of example and not as limitations to the scope of the invention as set forth in the accompanying claims.

What is claimed as novel is:

1. Apparatus for guiding a web fed along a given path and in a given plane, comprising (a) first roller means mounted for rotation about a first axis of rotation parallel to and to one side of said given plane,

(b) second roller means mounted for rotation about a second axis of rotation parallel to and on the other side of said given plane,

(c) said first and second axes of rotation being coplanar and lying in a second plane perpendicular to said given plane,

(d) pivot means mounting said first and said second roller means for pivotal movement,

(e) rocker means mounting said second roller means for movement toward and away from said first roller means, and

(f) biasing means urging said second roller means into engagement with said first roller means, said biasing means being located between and equidistant from the ends of said first and said second roller means,

(g) said rst and said second roller means gripping the web along a reference line as the web passes therebetween,

(l1) whereby walking of the web from the given path pivots the pivot means and therewith the first and second roiler means to a position where the first and second roller means grip the web along a line at an angle to the reference line, said first and second roller means and the web producing coaction forces to automatically effect the return of the web to the given path.

2. The apparatus of claim l wherein said biasing means is adjustable.

3. rthe apparatus of claim l, wherein said pivot means includes resilient means for damping any oscillations of said pivot means which may occur during pivotal movement thereof.

4. The apparatus of claim l, wherein (a) said first roller means comprises first and second spaced rollers,

(b) said second roller means comprises third and fourth spaced rollers,

(c) said first and said third rollers being positioned on opposite sides of and in contact with one edge of the web,

(d) said second and said fourth rollers, being positioned on opposite sides and in contact with the other edge of the web.

5. Apparatus for guiding a web fed along a given path and in a given plane, comprising (a) first roller means mounted for rotation about a first axis of rotation parallel to and on one side of said given plane,

(d) pivot means mounting said first and second roller means for pivotal movement,

(e) rocker means mounting said second roller means for movement toward and away from said rst roller means, and

v(g) said first and second roller means gripping the web along a reference line as the web passes therebetween,

(lz) centering roller means mounted for rotation about a third axis of rotation parallel to the given plane, said centering roller means having a surface in contact with the web surface, said contacting surfaces having a normal contact relationship,

`(i) pivoting means interconnected to said centering roller means for pivoting the centering roller means to a position wherein the centering roller means surface is still in contact with the web but having a contact relationship differing from the normal contact relationship,

(j) force transmitting means interconnecting said piv oting means to the pivot means mounting said first and said second roller means to transmit any motion of said pivot means to the pivoting means and thereby to the centering roller means,

(k) said centering roller means when moved by said pivoting means coacting with the web producing centering forces to return the web to the given path.

6. Apparatus for guiding a moving strip,

(a) a first roller,

(b) a pair of spaced support members rotatively carrying said first roller, said first roller being positioned in the space between the pair of spaced support members, to one side of the strip, and in contact with the surface of the strip along a reference line,

(c) a second roller,

(d) a pair of spaced rocker means, rockably mounted on said pair of spaced support members, rotatively carrying said second roller and rockably mounting said second roller for movement towards and away from said first roller, said second roller being positioned inthe space between the second pair of spaced rocker members, to the other side of the strip, and in contact with the surface of the strip along the said reference line,

(e) a base member interconnecting the pair of spaced support members,

(f) a cross member interconnecting the pair of spaced rocker members,

(g) a lip on said cross member thereon spaced from and parallel to said base member,

(Iz) biasing means positioned midway between the ends of said first and said second rollers in the space between and engaging said cross member and said base member, said biasing means coacting with said cross member and said base member to rock said pair of spaced rocker members and thereby bias said second roller towards said first roller whereupon said first and second rollers apply pressure to said strip as it passes between said rollers,

(i) a platform, and

(j) pivot means interconnecting said base member and said platform and balancing said base member in a balanced position,

(k) whereby walking of the strip, from a position centered with respect to the ends of the rollers, pivots the base member out of its balanced posiytion and therewith the first and second rollers to a position where the surfaces of the rollers contact the strip along a line at an angle to the reference line, said first and second rollers and the strip in the pivoted position coasting to produce restoring forces to return the strip to its centered position and the base mem-ber to its balanced position.

7. The apparatus of claim 6 wherein the pivot means includes resilient members coacting with said base member and platform to dampen any oscillation of said base member during pivotal movement thereof, said resilient 8. The apparatus of claim 6, wherein said adjustable biasing means includes,

(a) an externally threaded member,

(b) an internally threaded member threaded onto said externally threaded member, and

(c) a spring positioned around said externally threaded member between said base member and said internally threaded member,

(d) said spring being compressed or allowed to expand by rotating said internally threaded member and changing the position thereof with respect to the externally threaded member to vary the spring pressure against said lip and said base member and thereby vary the pressure between said rollers.

9. The apparatus of claim 6, including (a) an aperture formed in the cross member,

(b) a latch member pivotally mounted on the platform and extending through said aperture in said cross member,

(c) a catch formed on said iatch, said catch engaging an edge of said cross member adjacent said aperture when said rockable member and cross member are rocked in a direction which carries said second roller away from said first roller to thereby maintain said rollers spaced one from the other.

10. Apparatus for guiding a moving strip,

(a) a first roller,

(b) a pair of spaced support members rotatively carrying said irst roller, said first roller being positioned in the space between the pair of spaced support members, to one side of the strip, and in contact with the surface of the strip along `a reference line,

(c) a second rolier,

(d) a pair of spaced rocker means, rockably mounted on said pair of spaced support members, rotativeiy carrying said second roller and rockably mounting said second roller for movement towards and away trom said first roller, said second roller being positioned in the space between the second pair of spaced rocker members, to the other side ofthe strip, and in contact with the surface of the strip along the said reference line,

(e) a base member interconnecting the pair of spaced support members,

(f) a cross member interconnecting the pair of spaced rocker members,

(g) a llip on said cross member thereon spaced from and parallel to said base member,

(h) biasing means positioned midway between the ends of said rst and said second rollers in the space between said cross member and said base member, said biasing means engaging said cross member and said base member and coacting therewith to rock said pair of spaced rocker members and thereby bias said second roller towards said irst roller whereupon said rst and second rollers apply pressure to said strip as it passes between said rollers,

(i) a platform,

(j) pivot means interconnecting said base member and said platform and balancing said base member in a Ibalanced position,

(k) a third roller,

(l) a pair of spaced mounting members rotatively carrying said third roller, said third roller being positioned in the space between the pair of spaced mounting members and normally in contact with the surface of the strip along a predetermined portion of the strip,

(m) an interconnecting piece inetrconnecting the pair of spaced mountingmembers,

(n) a pivot pin mounting said interconnecting piece,

(o) an internally threaded biock pivoted to said interconnecting piece,

l(p) a bi-directional motor having a shaft, said shaft including an externally threaded portion mated with said internally threaded block,

(q) multi-position switch means for controlling the operation of and direction of said motor, and

(r) lever means interconnecting said muiti-position switch means to the base member and responsive to the pivotal movement of the base member to operate the motor and through said motor shaft to pivot the third roller to a position wherein it contacts the strip along a portion at an angle to the predetermined portion of the strip,

(s) said strip coacting with said third roller to produce forces which return the strip to the given path.

References Cited in the tile of this patent UNITED STATES PATENTS

Claims

1. APPARATUS FOR GUIDING A WEB FED ALONG A GIVEN PATH AND IN A GIVEN PLANE, COMPRISING (A) FIRST ROLLER MEANS MOUNTED FOR ROTATION ABOUT A FIRST AXIS OF ROTATION PARALLEL TO AND TO ONE SIDE OF SAID GIVEN PLANE, (B) SECOND ROLLER MEANS MOUNTED FOR ROTATION ABOUT A SECOND AXIS OF ROTATION PARALLEL TO AND ON THE OTHER SIDE OF SAID GIVEN PLANE, (C) SAID FIRST AND SECOND AXES OF ROTATION BEING COPLANAR AND LYING IN A SECOND PLANE PERPENDICULAR TO SAID GIVEN PLANE, (D) PIVOT MEANS MOUNTING SAID FIRST AND SAID SECOND ROLLER MEANS FOR PIVOTAL MOVEMENT, (E) ROCKER MEANS MOUNTING SAID SECOND ROLLER MEANS FOR MOVEMENT TOWARD AND AWAY FROM SAID FIRST ROLLER MEANS, AND (F) BIASING MEANS URGING SAID SECOND ROLLER MEANS INTO ENGAGEMENT WITH SAID FIRST ROLLER MEANS, SAID BIASING MEANS BEING LOCATED BETWEEN AND EQUIDISTANT FROM THE ENDS OF SAID FIRST AND SAID SECOND ROLLER MEANS, (G) SAID FIRST AND SAID SECOND ROLLER MEANS GRIPPING THE WEB ALONG A REFERENCE LINE AS THE WEB PASSES THEREBETWEEN, (H) WHEREBY WALKING OF THE WEB FROM THE GIVEN PATH PIVOTS THE PIVOT MEANS AND THEREWITH THE FIRST AND SECOND ROLLER MEANS TO A POSITION WHERE THE FIRST AND SECOND ROLLER MEANS GRIP THE WEB ALONG A LINE AT AN ANGLE TO THE REFERENCE LINE, SAID FIRST AND SECOND ROLLER MEANS AND THE WEB PRODUCING COACTION FORCES TO AUTOMATICALLY EFFECT THE RETURN OF THE WEB TO THE GIVEN PATH.