Method and system for controlling web speed
AssigneeE. I. Du Pont de Nemours and Company
InventorThomas Marion Greer
Life of this patent
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Abstract
A method and apparatus to reduce ripple in the signal produced by a transducer attached to a dancer roll, or web accumulator, where cyclic web motion is present. Two transducers are used, one to produce a dancer roll position signal, and another, responsive to the cyclic web drive, to produce a signal corresponding to the ripple component of the dancer roll position signal. An adder combines both signals to generate a third, ripple free signal indicative of the average dancer roll position in the web accumulator. This ripple free signal may be used to control the web speed.
Claims10
A method of controlling the speed of a web in a web transport, having a dancer roll and both continuous and intermittent drives, utilizing the average position of the dancer roll comprising the steps of:
- generating a first signal having unidirectional and bidirectional components corresponding to the instantaneous position of said dancer roll,
- generating a second signal having a bidirectional component related to the web movement produced by said intermittent drive,
- algebraically combining said first and second signals to produce a resultant signal indicative of the average position of said dancer roll, and
- controlling said continuous drive with said resultant signal, thereby to maintain the speed of said web relatively constant.
A system for controlling the speed of a web in a web transport having a dancer roll and both continuous and intermittent drives using the average position of said dancer roll comprising, in combination,
- sensor means for providing a first signal having a unidirectional and a bidirectional component corresponding to the instantaneous position of said dancer roll,
- transducer means for providing a second signal having a bidirectional component related to the web movement produced by said intermittent drive,
- adder means for algebraically combining said first and second signals to provide a resultant signal having a reduced bidirectional component that is indicative of the average position of dancer roll, and
- said continuous drive responsive to said resultant signal for maintaining the speed of said web constant.
Dependencies are inferred from the claim text.