US 6,856,850 B2Granted

Controlling web tension, and accumulating lengths of web, using a festoon

AssigneeKimberly-Clark Worldwide, Inc.

InventorsGregory John Rajala, Robert Donald Lorenz

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Abstract

This invention pertains to processing continuous webs such as paper, film, composites, and the like, in dynamic continuous processing operations. More particularly, it relates to accumulating limited lengths of such continuous webs and to controlling tension in such continuous webs during the processing operation. Both tension control and limited accumulations are achieved in festoon systems by connecting corresponding movably mounted festoon rolls to an actuator, sensing parameters such as position, tension, velocity, and acceleration related to the web and the festoon, and providing active force commands, in response to the sensed variables, to cause translational movement, generally including a target acceleration, in the movably mounted festoon rolls to control tension in the web while providing limited accumulation of a length of the web. The festoon control system can be used to attenuate tension disturbances, in the alternative to create controlled tension disturbances.

Claims55

Dependent claims

Processing apparatus defining a processing line, for advancing a continuous web of material through a processing step along a given section of the processing line, the processing apparatus comprising:

(a) first and second rolls defining a first nip;
(b) third and fourth rolls defining a second nip, the first and second nips collectively defining the given section of the web;
(c) a festoon, including at least one fixedly mounted festoon roll and at least two movably mounted festoon rolls, operating on the web in the given section of the processing line, thereby to control tension in the web and to accumulate a limited length of the web sufficient to sustain operation of the process on the length of web during routine temporary stoppages of web feed to the given section of the processing line or taking the web away from the given section of the processing line;
(d) an actuator applying net translational force to the movably mounted festoon rolls;
and
(e) a controller driving the festoon, and computing and controlling net translational acceleration of the movably mounted festoon rolls such that the festoon is effective to control tension, at a desired level of constancy, and to accumulate a limited length of the web, in the respective section of the processing line.

3 more elements

In a processing operation wherein a continuous web of material is advanced through a processing step defined by first and second spaced nips, each nip being defined by a pair of nip rolls, a method of controlling web tension, and of accumulating a limited length of the web, in the respective section of web, the method comprising:

(a) providing a festoon, having at least one fixedly mounted festoon roll and at least two movably mounted festoon rolls, operative on the respective section of web;
(b) applying a first generally static force component to the movably mounted festoon rolls, the first generally static force component having a first value and direction;
(c) applying a second variable force component to the movably mounted festoon rolls, the second variable force component having a second value and direction, modifying the first generally static force component, and thereby modifying (i) the effect of the first generally static force component on the movably mounted festoon rolls and (ii) corresponding translational acceleration of the movably mounted festoon rolls;
and
(d) adjusting the value and direction of the second variable force component repeatedly, each such adjusted value and direction of the second variable force component (i) replacing the previous such value and direction of the second variable force component and (ii) acting in combination with the first static force component to provide a target net translational acceleration to the movably mounted festoon rolls.

2 more elements

In a processing operation wherein a continuous web of material is advanced through a processing step, a method of controlling the tension in the respective section of the web, comprising:

(a) providing a festoon, having at least one fixedly mounted festoon roll, and at least two movably mounted festoon rolls, operative for controlling tension on the respective section of web;
(b) providing an actuator to apply an actuating force to the movably mounted festoon rolls;
(c) measuring a first velocity of the web after the festoon;
(d) measuring a second velocity of the web at the festoon;
(e) measuring motor current of the actuator;
(f) measuring web tension before the festoon;
(g) measuring web tension after the festoon;
(h) measuring translational velocity of the movably mounted festoon rolls;
(i) sensing the position of the movably mounted festoon rolls;
(j) measuring acceleration of the movably mounted festoon rolls;
and
(k) providing force control commands to the actuator based on the above measured values, including computed acceleration A*p of the movably mounted festoon rolls, to thereby control the actuating force imparted to the movably mounted festoon rolls by the actuator to control the web tension.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/279,649Filed 24 Oct 2002 · continuation in part
Priority: 3 Jul 1998
Published: US 2003/0052148 A120 Mar 2003
Granted: 15 Feb 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

B65H 23/1825
In unwinding mechanisms or in connection with unwinding operations: and controlling web tension
B65H 23/048
Longitudinally: by positively actuated movable bars or rollers
B65H 23/063
By retarding devices, e.g. acting on web-roll spindle: and controlling web tension
B65H 23/1888
In connection with running-web: and controlling web tension

Family

Application09/110,753Parent of this continuation-in-part · filed 3 Jul 1998
Application09/978,474Parent of this continuation-in-part · filed 16 Oct 2001
US 2003/0052148 A1Pre-grant publication · published 20 Mar 2003
US 6,473,669 B2Parent of this continuation-in-part
US 6,314,333 B1Parent of this continuation-in-part
US 2002/0059013 A1Published application
US 6,856,850 B2This patent

From the US filing history. Foreign family members aren’t listed.