Tension control system for web-feeding mechanisms

Claim 1

A TENSION CONTROL SYSTEM FOR USE WITH WEB-FEEDING MECHANISMS, COMPRISING: A FORCE-BALANCING VALVE UNIT, INCLUDING A VALVE MEMBER MOVABLY MOUNTED THEREON, A FIXED ORIFICE FORMED IN SAID VALVE UNIT AND VALVED BY SAID MEMBER TO FORM A FLUID-RELEASE ORIFICE THEREBETWEEN, AND MEANS FORMING A PRESSURE SUPPORT CYLINDER FOR BIASING SAID MEMBER; MEANS FOR APPLYING A FORCE, PROPORTIONAL TO THE TENSION IN A WEB FED BY SAID MECHANISM, TO SAID VALVE MEMBER IN A DIRECTION OPPOSITE TO THE BIAS OF SAID PRESSURE SUPPORT CYLINDER; FLUID SUPPLY MEANS; FIRST CONDUIT MEANS INCLUDING PRESSURE-REGULATING MEANS FOR DELIVERING FLUID FROM SAID FLUID SUPPLY MEANS TO SAID SUPPORT CYLINDER UNDER A PREDETERMINED REGULATED PRESSURE TO BALANCE SAID TENSION FORCE FOR VARYING THE AREA OF SAID FLUID-RELEASE ORIFICE AS A CONTINUOUS FUNCTION OF THE RELATIONSHIP BETWEEN THE REGULATED PRESSURE AND THE APPLIED TENSION FORCE; SECOND CONDUIT MEANS CONNECTED WITH SAID FLUIDRELEASE ORIFICE; ORIFICE MEANS CONNECTED FOR DELIVERING FLUID FROM SAID SUPPLY MEANS AT A LIMITED RATE OF FLOW TO SAID SECOND CONDUIT MEANS FOR CONTROL OF THE PRESSURE THEREIN BY THE OPENING OF SAID FLUID-RELEASE ORIFICE; AND WEB TENSION CONTROL MEANS CONNECTED FOR CONTROL BY THE PRESSURE IN SAID SECOND CONDUIT MEANS TO MAINTAIN THE WEB TENSION SUBSTANTIALLY AT A PREDETERMINED MEAN VALUE DEPENDENT UPON THE LEVEL OF THE REGULATED PRESSURE DELIVERED TO SAID SUPPORT CYLINDER.