US20050230449A1

Movatterモバイル変換

Info

Publication number: US20050230449A1
Application number: US11/110,616
Authority: US
Inventors: Thomas Meyer; Chris Nelson; Brian Krueger
Original assignee: Joa Curt G Inc
Current assignee: Joa Curt G Inc
Priority date: 2004-04-20
Filing date: 2005-04-20
Publication date: 2005-10-20

Abstract

An improved web accumulator with two arms where at least one arm is a swinging dancer arm and at least one arm is attached to a sliding carriage. Each arm has a set of rollers attached. A web is threaded alternately between the two sets of rollers. The arms are mechanically connected to move simultaneously towards or away from each other. The arms are initially position at their maximum separation to accumulate a maximum length of web. When web infeed is interrupted while web outfeed or draw persists, the arms are first rotated in towards each other to pay out the stored length of web. As the demand persists and the dancer arm is rotated beyond some predefined position, the sliding carriage begins to slide to a least storage position. As web infeed returns to normal operational speeds, the dancer arm and the sliding carriage are returned to their original position to again accumulate a maximum amount of web.

Description

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/563,840, filed 20 Apr. 2004, and entitled “Method of Increasing Web Storage in a Dancer.”

BACKGROUND OF THE INVENTION

The invention disclosed herein relates to a method for increasing the amount of web storage available from a web accumulation dancer system. The invention pertains to an accumulator for accumulating a substantial length of a running web such that if the infeed to the accumulator is stopped or slowed for a short interval the web in storage is paid out continuously to a web-utilizing device so that the device has a constant web supply and thus need not be slowed or stopped. Increased storage is an imperative for successful operation of zero speed splicing at very high machine speeds.

A common use of a web accumulator is where a web is fed from a primary supply wheel and it is necessary to splice the leading edge of the web from a standby supply wheel to the trailing edge of the web from the primary supply wheel in a manner that will not cause interruption of the web supply to a web consuming or utilizing device.

In one known type of accumulator, the swinging dancer arm type, there is a set of spaced apart rollers on a swingable dancer arm cooperating with another set of rollers on an arm that may be stationary or swingable. A web is looped back and forth between the sets of rollers on opposed arms in a serpentine fashion. When the swingable arm is swung away from the other arm a substantial length of web is accumulated. During normal running of the web the arms will be urged to their maximum practical separation from each other to accumulate the maximum length of web. If the infeed web is slowed or stopped for a short time the tension in the web urges the arms to the minimum separation position in order to make the accumulated web available to the machine. After infeed to the accumulator is resumed the arms separate again and return to their original position to accumulate and store another length of web.

In another known type of accumulator, the linear sliding carriage type, there is a set of rollers mounted on a movable carriage which can run linearly toward or away from a set of corresponding rollers which may either be stationary or similarly slidably mounted. During normal operation of the accumulator, the two sets of rollers will be slid to their maximum practical separation to accumulate the maximum amount of web. If the infeed supply to the web accumulator is slowed or stopped, the rollers will be slid toward each other to allow the stored web to be paid out. As the web infeed is returned to regular operational speed the movable rollers slide back toward the original position to accumulate another length of web.

It is well known in the art that the swinging arm dancer type of web accumulator first discussed is efficient in that the friction losses to the web are low. However, the dancer type of accumulator does not store a sufficient length of web. Alternatively, the linear sliding carriage type of accumulator allows more web to be accumulated; however, more frictional losses occur.

The consequences of friction and inertia may be appreciated when it is realized that the web may be running at a very high speed when suddenly, for some reason, such as when making a splice, the infeeding web is stopped or decelerated. This change in web motion will result in a reaction by the components of the accumulator. Most notable of these reactions is the motion imparted to the movable assembly of the accumulator. After the web is slowed or stopped, the web at the infeed can only accelerate as fast as the rollers can accelerate. The force to accelerate the rollers is provided by tension in the web. Minimizing the number of rollers and minimizing the inertia of each roller minimizes the necessary web tension.

Minimization and control of the inertia and friction associated with this reaction is therefore an important desired attribute of such accumulators. There is an important need for a web accumulator which provides the benefits of low friction and minimized inertia, allowing it to handle the most delicate of webs at high speeds without breakage or loss of control.

The invention disclosed herein combines a swinging arm dancer with a linear slide. Thus the invention disclosed herein has the advantage of web storage capability substantially equal to that of a linear accumulation system but with minimized frictional losses.

SUMMARY OF THE INVENTION

The new arrangement combines the best features of both previously known accumulators to gain the advantages of both systems while eliminating the disadvantages of each. The new web accumulator achieves a large amount of web storage for the amount of rollers it utilizes.

In general terms, the preferred new web accumulator includes arms, each arm has a set of rollers attached. A web is threaded alternately between the two sets of rollers. The arms are mechanically connected to move simultaneously towards or away from each other. The arms are initially position at their maximum separation to accumulate a maximum length of web. When web infeed is interrupted while web outfeed or draw persists, the arms are first rotated in towards each other to pay out the stored length of web. As the demand persists and the dancer arm is rotated beyond some predefined position, the sliding carriage begins to slide to a least storage position. As web infeed returns to normal operational speeds, the dancer arm and the sliding carriage are returned to their original position to again accumulate a maximum amount of web.

There are several possible variations to this system, such as vertical or horizontal orientation, one or more swinging dancer arms, and either the dancer arm or the linear arm can be sliding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of the preferred embodiment of the web accumulator.

FIG. 2 is a side elevational view of the accumulator ofFIG. 1.

FIG. 3 is a simplified front elevational view of the preferred embodiment of the accumulator of the present invention with its roller carrying arms in the position in which the maximum length of web is accumulated.

FIG. 4 is a similar toFIG. 3 except that the dancer arms of the accumulator are rotating toward each other as would be the case when infeed of the web is stopped and the length of web that is stored in the accumulator is being paid out.

FIG. 5 is similar toFIG. 4 except that the dancer arms of the accumulator have begun to slide toward each other to further pay out the stored web material.

FIG. 6 is similar toFIG. 5 except that the dancer arms of the accumulator have slid to the least storage position.

FIG. 7 is a simplified front elevational view of an alternate embodiment of the accumulator of the present invention with its roller carrying arms in the position in which the maximum length of web is accumulated.

FIG. 8 is similar toFIG. 7 except that the swinging dancer arm of the accumulator is rotating toward the nonrotating linear arm as would be the case when infeed of the web is stopped and the length of web which is stored in the accumulator is being paid out.

FIG. 9 is similar toFIG. 8 except that the nonrotating linear arm has begun to slide toward the rotating arm to further pay out the stored web material.

FIG. 10 is similar toFIG. 9 except that the arms of the accumulator are in the least storage position.

FIG. 11 is a front elevational view of an alternate embodiment of the web accumulator.

FIG. 12 is simplified front elevational view of the accumulator ofFIG. 11 with its roller carrying dancer arms in the position in which the maximum length of web is accumulated.

FIG. 13 is a similar toFIG. 12 except that the dancer arms of the accumulator are rotating toward each other as would be the case when infeed of the web is stopped and the length of web that is stored in the accumulator is being paid out.

FIG. 14 is similar toFIG. 13 except that the dancer arms of the accumulator have begun to slide toward each other to further pay out the stored web material.

FIG. 15 is similar toFIG. 14 except that the dancer arms of the accumulator have slid to the least storage position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention.

FIG. 1 illustrates the preferred embodiment of thenew web accumulator20. Theaccumulator20 consists of a first swingingdancer arm22 rotatably mounted to afirst carriage24.First dancer arm22 rotates aboutaxle shaft26. A firstpneumatic actuator28 is attached to bothfirst carriage24 andfirst dancer arm22 such that theactuator28 will function to rotate thedancer arm22 aboutaxle shaft26.Dancer arm22 supports a first set ofweb accumulator rollers30 which are individually numbered30A-30F, inclusive (see, e.g.,FIG. 3.) Theweb accumulation rollers30A-30F, inclusive, are rotatably mounted on thedancer arm22. Thecarriage24 is slidably mounted on anupper track32 and alower track34.

On the opposite end of the

tracks

32 and34 is a secondswinging dancer arm36 which is preferably identical to first swingingdancer arm22, but rotated 180 degrees from the first swingingdancer arm22.Second dancer arm36 is rotatably mounted to asecond carriage38 for rotation aboutsecond axle shaft40. A second pneumatic actuator is attached to thesecond dancer arm36 and thesecond carriage38 to facilitate rotation of thesecond dancer arm36 about thesecond axle shaft40. Thesecond carriage38 is slidably mounted to theupper track32 and thelower track34. A second set ofweb accumulator rollers44 which are individually numbered as44A-44E (seeFIG. 2), inclusive are rotatably mounted on thesecond dancer arm36.

The drive system includes two

idler arms

46 and48 with flexiblemechanical linkage50. In the preferred embodiment of this invention, the flexible mechanical linkage is a toothed belt.

Slidable carriages

24 and38 are affixed to the belt such that they will not move independently of each other and can only move simultaneously in opposite directions.

Carriages

24 and38 are attached to the toothed belt by

clamps

52 and54, respectively. The drive system is driven byservomotor56.

It will be noted that in the illustrated embodiment the roller set30 includes six (6) individual rollers and the roller set44 includes five (5) rollers. This number can be varied using either a lesser or greater number of rollers as selected for a particular application. However, it will be obvious to one of skill in the art that in order to loop the web between the arms and practice the invention as described herein, the first roller set30 should include at least two individual rollers and the second roller set44 should include at least one individual roller. The sets of

rollers

30 and44 are common in the art and therefore are of known configuration.

InFIG. 1 theaccumulator20 is in its maximum storage position as would be the case when theweb60 is being drawn out of theaccumulator20 and is being fed into theaccumulator20 at the same rate. The

dancer arms

22 and36 are swung apart as far as is practical to store the maximum amount ofweb60 in the form of loops running back and forth between the

dancer arms

22 and36.

Theweb60 is fed into theweb accumulator20. Theweb60 first passes around anidler roll assembly58 which is mounted on thesecond carriage38. Theweb60 then passes around thefirst roller30A of roller set30 mounted onfirst dancer arm22 and next around thefirst roller44A of the roller set44 mounted onsecond dancer arm36. Theweb60 continues to alternate between the consecutive rollers of roller set30 and roller set44 until theweb60 has passed over all the rollers. Theweb60 then exits theaccumulator20 and is fed to a web utilization device (not shown).

FIG. 2 is a side elevation view of theaccumulator20 ofFIG. 1. This view shows how theindividual rollers44A-44E of roller set44 are rotationally mounted todancer arm36. This view also shows how thedancer arm36 is attached to thesecond axle shaft40 and to thesecond actuator42.Servomotor56 is shown withidler arm48 shown in phantom lines.

Referring now toFIGS. 3, 4,5, and6, the

dancer arms

22 and36 are shown rotating and driven towards each other to pay out accumulatedweb60 to the outfeed when infeed ofweb60 is stopped for a short interval.FIG. 3 shows theweb accumulator20 in the maximum storage position.FIG. 4 shows the

dancer arms

22 and26 as they are swinging towards each other. The

dancer arms

22 and36 swing towards each other until some specified point when, as shown inFIG. 5, the

carriages

24 and38 on which the

dancer arms

22 and36 are mounted begin to slide toward each other to further continue pay out.FIG. 6 shows theweb accumulator20 in its least storage position, which is the position at which the

dancer arms

22 and26 are the closest.

More specifically, the control of the sliding

carriages

24 and38 is dependent on the displacement of the

dancer arms

22 and36. As the web infeed is slowed or stopped, the tension due to drawing theweb60 from the outfeed end of theweb accumulator20 causes the

dancer arms

22 and36 to move towards the less storage position while the length ofweb60 in storage is paid out. The web tension causes the

dancer arms

22 and36 to begin to move. However, the

actuators

28 and42 help drive the swinging

dancer arms

22 and36 to overcome the inertia and friction losses of the roller sets30 and44 and

dancer arms

22 and36. If the

dancer arms

22 and36 and roller sets30 and44 had no inertia or frictional losses, the force applied to the

dancer arms

22 and36 by the web tension forces would be sufficient to rotate the

dancer arms

22 and36 to the appropriate positions to pay out the stored web. However, because friction and inertia are a factor, the

actuators

28 and42 must drive the

rotating dancer arms

22 and36 to overcome the losses from friction and inertia.

When the

dancer arms

22 and36 reach some predetermined position, thecarriage slide drive56 is commanded to move the

carriages

24 and38 towards each other. Under normal circumstances the

carriages

24 and38 maintain their preset position. In this manner nominal changes in

dancer arm

22 and36 positions are ignored.

As discussed above, the

carriages

24 and38 are mechanically coupled to each other through thedrive belt50 such that they move away from or towards each other synchronously. The velocity of the

carriages

24 and38 is proportional to the rate of displacement of the

dancer arms

22 and36. This allows the system to pay outweb60 such that the web utilizing device is not slowed or stopped. Theservomotor56 is given the command to move the sliding

carriages

24 and38 to the least storage position at a velocity proportional to the displacement error of the

dancer arm

22 and36 position.

As the displacement error is nullified, thecarriage slide drive56 is slowed to a stop even if it has not reached its final commanded position. If the error goes negative, thecarriage slide drive56 is commanded to return the sliding

carriages

24 and38 to the preset position at a velocity proportional to the

dancer arm

22 and36 error.

FIGS. 7, 8,9, and10 depict the operation of an alternate embodiment of the web accumulator of the present invention. The alternate embodiment shown inFIG. 7 consists of a firstlinear arm122 with a set ofrollers130 rotatably mounted thereon. Thelinear arm122 is nonrotatably attached to acarriage124. Thecarriage124 is slidably mounted on a set of tracks (not shown). Thecarriage124 is mounted in a known fashion, as described regarding the preferred embodiment above. At the other side of theweb accumulator120 ofFIG. 7 is a swingingdancer arm136 mounted to aplate138. Thedancer arm136 has a set ofrollers144 rotatably attached thereon.

FIG. 7 shows this alternate embodiment of theaccumulator120 in its maximum web storage position. When the infeed to the accumulator stops or slows, thedancer arm136 swings toward the linear arm as shown inFIG. 8. When thedancer arm136 rotates past some predetermined point, thecarriage124 upon whichlinear arm122 is mounted begins to slide towarddancer arm136 as can be seen inFIG. 9.FIG. 10 shows this alternate embodiment of theaccumulator120 in its least storage position.

Another alternate embodiment of the invention (not shown) has one swinging dancer arm and one linear arm, as described above inFIG. 7. However, in this embodiment the swinging dancer arm is slidably mounted on tracks while the linear arm is stationary. When the web infeed slows or stops, the web will pull the swinging dancer arm toward the stationary linear arm. At some predetermined point the dancer arm will be slid toward the stationary linear arm to pay out the remaining accumulated web.

FIGS. 11-15 illustrate yet another alternate embodiment of theweb accumulator220 of the present invention. This embodiment is similar to the preferred embodiment of the invention, however in this embodiment the first swingingdancer arm222 and the second swingingdancer arm236 are mirror images of each other. As shown inFIG. 11, theweb accumulator220 consists of a first swingingdancer arm222 rotatably mounted to afirst carriage224 and a secondswinging dancer arm236 rotatably mounted to asecond carriage238. The first and

second carriages

224,238 are slidably attached to anupper track232 and alower track234. The swinging

dancer arms

222,236 and

carriages

224,238 operate in the manner as described above regarding the preferred embodiment above.

FIG. 12 shows this alternate embodiment of theweb accumulator220 in its maximum web storage position. When the infeed to theaccumulator220 slows or stops, the

dancer arms

222,236 swing toward each other as shown inFIG. 13. When the

dancer arms

222,236 rotate past some predetermined point, the first and

second carriages

224,238 begin to slide towards each other as seen inFIG. 14.FIG. 15 shows this alternate embodiment of theweb accumulator220 in its least storage position.

The embodiments described above, and depicted in theFIGS. 1-15 disclose a web accumulator with a horizontal orientation. That is, the carriages slide on tracks in a horizontal direction. However, it is within the purview of the invention to utilize the web accumulator, as disclosed above, with a vertical orientation.

The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention.

Claims

1. A web accumulator for accumulating and paying out a portion of a continuous moving web passing through the accumulator comprising:

a first rotating dancer arm carrying a first plurality of rollers for engaging a moving web;

a second dancer arm carrying a second plurality of rollers for engaging said web;

at least one of said arms being slidably mounted to a body;

a drive mechanism associated with said slidably mounted arm, wherein said slidably mounted arm can be driven in a first substantially linear direction toward the other arm, and a second substantially linear direction away from the other arm;

whereby the length of travel of the web can be varied by radial movement of the first rotating dancer arm and linear movement of at least one of the dancer arms.

2. A web accumulator according toclaim 1, said first rotating dancer arm carried by a first carriage.

3. A web accumulator according toclaim 2, said second dancer arm carried by a second carriage.

4. A web accumulator according toclaim 3, said first and second carriages coupled to each other, wherein said both said first and second carriages are slidably mounted to a body.

5. A web accumulator according toclaim 4, said first and second carriages coupled by a toothed belt, wherein movement of said belt cause movement of said first and second carriages.

6. In combination, a linear accumulator and a rotating arm dancer, wherein said rotating arm dancer and said linear accumulator operate in conjunction to first accumulate and second pay out a portion of a continuous moving web passing through the accumulator.

7. A web accumulator for accumulating and paying out a portion of a continuous moving web passing through the accumulator comprising:

a second rotating dancer arm carrying a second plurality of rollers for engaging said web;

at least one of said arms being slidably mounted to a body;

whereby the length of travel of the web can be varied by linear movement of at least one of the dancer arms and radial movement of the first rotating dancer arm.

8. A web accumulator according toclaim 7 wherein the second arm is identical to the first arm.

9. A web accumulator according toclaim 8, said second arm rotated approximately 180 degrees from from said first arm when said arms are in a maximum storage position.

10. A web accumulator according toclaim 7 wherein the second arm is a mirror image of the first arm and the arms are configured such that an angle of approximately 90 degrees is formed between the arms when the arms are in a maximum storage position.