Web feeding machines

Abstract

A web feeding machine for controlling the feed of a web of material comprises a first pair of rollers which bear against one another to form a first nip, a second pair of rollers which bear against one another to form a second nip downstream from the first nip, means to cause the ratio of the linear speed of the web through the second nip to that through the first nip to be a constant and to have a value greater than one, a variable speed drive for driving the nip rollers, means for monitoring the tension T.sub.1 in the web upstream from the first nip and the tension T.sub.2 between the first and second nips, and control means to control the variable speed drive of the rollers so that the angular velocity .omega. of the rollers satisfies the expression: ##EQU1## where A, B and C are constants. By controlling the angular velocity of the rollers and hence the linear speed of the web in accordance with this expression, a constant flow rate of the web is ensured irrespective of the elasticity of the web or the overall speed of its feed.

Dependencies are inferred from the claim text.