Patent ID: 6543353
Filing Date: 2003-04-08
Classification: B41F,B65H,G01L

Abstract:
A method for monitoring a moving web of material including:measuring a first web tension of said moving web of material at a first time; measuring a second web tension of said moving web of material at a second time subsequent to said first time; determining a difference between said first web tension and said second web tension; using said difference between said first web tension and said second web tension as a value of a change of said web tension per unit of time; providing a threshold value of said change of said web tension per unit of time; comparing said value of said change of said web tension per unit of time with said threshold value of said change of said web tension per unit of time; generating a signal when said value of said change of said web tension per unit of time exceeds said threshold value of said change of said web tension per unit of time; and determining the occurrence of a tear in said web of material from said generation of said signal.