Electronic web tension measuring and controlling system

Claim 2

A web tension control system for controlling the web tension in a traveling web comprising sensing means for sensing the actual tension on the web at a predetermined station during the travel of said web, and for producing a first electrical output signal in accordance with the actual tension, set point control means for producing a second electrical signal proportional to a desired Web tension per unit width of the web, said set point control means comprising adjustable means calibrated directly in tension force per unit width of the web means for producing a third signal proportional to actual web tension per unit length of the web comprising adjustable control means for controlling said first signal as a function of the width of said web, means for summing said second signal and said third signal and for producing an error signal in accordance with the difference between said second and third signals, and web tension control means responsive to said error signal for controlling the web tension in accordance therewith.

Claim 3

A system as claimed in claim 1 wherein said adjustable control means for producing said third signal comprises potentiometer means directly calibrated in units of web width and wherein said tension set point control means comprises potentiometer means calibrated in units of web tension per unit web width.

Claim 4

A system as claimed in claim 1 further comprising means for multiplying said error signal by a factor proportional to the width of the web to produce an error signal proportional to the total web tension error.

Claim 5

A system as claimed in claim 3 wherein said multiplying means comprises an operational amplifier connected as a summing amplifier and having variable resistance means connected in the feedback circuit thereof, the setting of said variable resistance means being calibrated in terms of web width.

Claim 6

A system as claimed in claim 1 further comprising indicating means responsive to said third signal for providing a visual indication of the actual tension in units of force per unit width.

Claim 7

A web tension control system for controlling the tension in a traveling web comprising sensing means for sensing the actual tension on the web at a predetermined station during the travel of said web, and for producing a first electrical output signal in accordance with the actual tension, set point control means for producing a second electrical signal proportional to a desired web tension per unit width of the web, means for producing a third signal comprising adjustable control means for controlling said first signal as a function of the width of said web, means for summing said second signal and said third signal and for producing an error signal in accordance with the difference between said second and third signals, and web tension control means responsive to said error signal for controlling the web tension in accordance therewith, said system further comprising means for providing proportional plus reset control of said error signal, said proportional plus reset control means comprising an operational amplifier connected as a summing amplifier, a first variable resistance device connected in an input circuit of said amplifier a second variable resistance device connected in the feedback circuit of said operational amplifier, means for ganging said variable resistance devices together so that a change in the setting of one of the devices is accompanied by a corresponding change in the setting of the other device and a capacitor connected in the feedback path of said amplifier for controlling the output voltage of said amplifier in accordance with the rate of charging thereof as determined by the setting of said variable resistance devices.

Claim 8

A web tension control system for controlling the tension in a traveling web comprising sensing means for sensing the actual tension on the web at a predetermined station during the travel of said web, and for producing a first electrical output signal in accordance with the actual tension, set point control means for producing a second electrical signal proportional to a desired web tension per unit width of the web, means for producing a third signal comprising adjustable control means for controlling said first signal as a function of the width of said web, means for summing said second signal and said third signal and for producing an error signal in accordance with the difference between said second and third signals, and web tension control means responsive to said error signal for controlling the web tension in accordance therewith, said system further comprising means for providing proportional plus reset control of said error signal, said proportional plus reset control means comprising an operational amplifier connected as a summing amplifier, a first variable resistance device connected in an input circuit of said amplifier a second variable resistance device connected in the feedback circuit of said operational amplifier, means for ganging said variable resistance devices together so that a change in the setting of one of the devices is accompanied by a corresponding change in the setting of the other device and a capacitor connected in the feedback path of said amplifier for controlling the output voltage of said amplifier in accordance with the rate of charging thereof as determined by the setting of said variable resistance devices.

Claim 9

A system as claimed in claim 6 further comprising a transistor connected in an emitter-follower configuration with the base electrode thereof connected to the output of said operational amplifier and the emitter electrode connected to one plate of said capacitor and to said web tension control means.

Claim 10

A system as claimed in claim 7 further comprising means for controlling the biasing of said transistor to limit the output thereof and to thereby limit the magnitude of the error signal transmitted to said web tension control means.

Claim 11

A system as claimed in claim 8 wherein said biasing control means comprises a potentiometer the output of which is connected to the colleCtor electrode of said transistor, the input ends of said potentiometer being respectively connected to positive and negative supply voltage terminals, said system further comprising switching means for controlling the connection of said potentiometer to said transistor, said switching means including at least one switch having a first position wherein the output of said potentiometer is connected to said collector electrode and a second position wherein said potentiometer is bypassed and said collector electrode is directly connected to said positive supply voltage terminal.

Claim 12

A system as claimed in claim 9 wherein said switching means comprises a plurality of said switches, said switches being located positions remote from each other to provide independent control.

Claim 13

A web tension control system for controlling the tension in a traveling web comprising sensing means for sensing the actual tension on the web at a predetermined station during the travel of said web, and for producing a first electrical output signal in accordance with the actual tension, set point control means for producing a second electrical signal proportional to a desired web tension per unit width of the web, means for producing a third signal comprising adjustable control means for controlling said first signal as a function of the width of said web, means for summing said second signal and said third signal and for producing an error signal in accordance with the difference between said second and third signals, and web tension control means responsive to said error signal for controlling the web tension in accordance therewith, said system further comprising preset means for presetting the amount of tension to be applied by said tension control means before winding of said web is begun, said preset means including a manually-operated override circuit for limiting the amount of tension to be applied by said tension control means so as to enable the operator to select a predetermined amount of unwind tension prior to winding.

Claim 14

A web tension control system for controlling the tension in a traveling web comprising sensing means for sensing the actual tension on the web at a predetermined station during the travel of said web, and for producing a first electrical output signal in accordance with the actual tension, set point control means for producing a second electrical signal proportional to a desired web tension per unit width of the web, means for producing a third signal comprising adjustable control means for controlling said first signal as a function of the width of said web, means for summing said second signal and said third signal and for producing an error signal in accordance with the difference between said second and third signals, and web tension control means responsive to said error signal for controlling the web tension in accordance therewith, said system further comprising preset means for presetting the amount of tension to be applied by said tension control means before winding of said web is begun, said preset means including a manually-operated override circuit for limiting the amount of tension to be applied by said tension control means so as to enable the operator to select a predetermined amount of unwind tension prior to winding.

Claim 15

A system as claimed in claim 11 further comprising an operational amplifier connected to the output of said summing means, said preset means comprising a transistor having the base electrode thereof connected to the output of said operational amplifier and the emitter electrode connected in the feedback path of said operational amplifier and to said web tension control means and means for controlling the biasing of said transistor to limit the output thereof and to thus limit the error signal transmitted to said web tension control means.

Claim 16

A system as claimed in claim 11 wherein said override circuit includes a potentiometer and a switch for shorting out the potentiometer so as to permit full tension to be applied by said tension control means.

Claim 17

A system as claimed in claim 11 further comprising an operational amplifier connected to the output of said summing means and a capacitor connected in a feedback path of said operational amplifier, said override circuit comprising circuit means, including a potentiometer, for limiting the output of said operational amplifier and for driving said capacitor.

Claim 18

A web tension responsive system comprising a web tension measuring means for measuring the tension on a traveling web comprising transducer means for sensing the actual tension on the web at a predetermined station along the travel of said web and for producing an electrical signal in accordance with the actual tension, operational amplifier means for amplifying said output signal, adjustable control means for controlling said output signal as a function of the width of the web, and indicating means responsive to the output of said control means for producing an output proportional to the tension pressure exerted on the web as a function of the lineal width of said web, said adjustable control means comprising a potentiometer the settings of which are calibrated in units of web width and said operational amplifier means comprising a first operaTional amplifier connected between the output of said transducer means and the input of said potentiometer and a second operational amplifier connected between the output of said potentiometer and the input of said indicating means, said operational amplifiers being connected as summing amplifiers.

Claim 19

A web tension responsive system comprising a web tension measuring means for measuring the tension on a traveling web comprising transducer means for sensing the actual tension on the web at a predetermined station along the travel of said web and for producing an electrical signal in accordance with the actual tension, operational amplifier means for amplifying said output signal, adjustable control means for controlling said output signal as a function of the width of the web, and indicating means responsive to the output of said control means for producing an output proportional to the tension pressure exerted on the web as a function of the lineal width of said web, said adjustable control means comprising a potentiometer the settings of which are calibrated in units of web width and said operational amplifier means comprising a first operaTional amplifier connected between the output of said transducer means and the input of said potentiometer and a second operational amplifier connected between the output of said potentiometer and the input of said indicating means, said operational amplifiers being connected as summing amplifiers.

Claim 20

A system as claimed in claim 15 further comprising web tension control means comprising tension set point potentiometer means for producing an electrical output signal in accordance with a desired tension, summing means for algebraically summing said desired tension signal and the output signal of said second operational amplifier to produce an error signal and means responsive to said error signal for controlling the web tension.