Electrohydraulic drive for process line winders, unwinders and other equipment

Claim 2

An electrohydraulic drive and control system for a rotating member that engages and controls the speed and tension in an indefinite length of material in a process line, comprising a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, and an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) said speed limit control signal and (iii) said pressure limit control signal, said speed limit control signal being an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve.

Claim 3

The drive and control system of claim 1 wherein said regeneration circuit also includes a check valve that blocks a fluid flow from said feed line to said regeneration circuit, a fluid dividing means, and second means for setting an adjustable fixed pressure in said return line, said second pressure setting means being in fluid communication between said return line and said fluid dividing means.

Claim 4

The drive and control system of claim 2 wherein said second pressure setting means includes means for limiting the pressure upstream of said second means to a predetermined set value less than the set pressure of said first pressure setting means and in excess of the pressure in said feed line.

Claim 5

The drive and control system of claim 1 further comprising means for measuring the speed or rotation of said motor and converting said measurement into an electrical speed signal proportional to said speed and having a polarity indicative of the direction of rotation of said motor.

Claim 6

An electrohydraulic drive and control system for a rotating member that engages and controls the speed and tension in an indefinite length of material in a process line, comprising a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) a said speed limit control signal and (iii) a said pressure limit control signal, said speed limit control signal being an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, and further comprising means for measuring the speed of rotation of said motor and converting said measurement into an electrical speed signal proportional to said speed and having a polarity indicative of the direction of rotation of said motor, wherein said electronic control circuit includes an integrating servo-amplifier that receives said speed signal and said speed limit control signal.

Claim 7

An electrohydraulic drive and control system for a rotating member that engages and controls the speed and tension in an indefinite length of material in a process line, comprising a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) a said speed limit control signal and (iii) a said pressure limit control signal, said speed limit control signal being an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, and further comprising means for measuring the speed of rotation of said motor and converting said measurement into an electrical speed signal proportional to said speed and having a polarity indicative of the direction of rotation of said motor, wherein said electronic control circuit includes an integrating servo-amplifier that receives said speed signal and said speed limit control signal.

Claim 8

An electrohydraulic drive and control system for a rotating member that engages and controls the speed and tension in an indefinite length of material in a process line, comprising a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, and an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) a said speed limit control signal and (iii) a said pressure limit control signal, and speed limit control signal having an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, and means for measuring the speed of rotation of said motor and converting said measurement into an electrical speed signal proportional to said speed and having a polarity indicative of the direction of rotation of said motor, wherein said electronic control circuit further includes an analog multiplier that multiplies the output signal of said integrating servoamplifier and said pressure limit control signal to produce a weighted output signal.

Claim 9

An electrohydraulic drive and control system for a rotating member that engages and controls the speed and tension in an indefinite length of material in a process line, comprising a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, and an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) a said speed limit control signal and (iii) a said pressure limit control signal, and speed limit control signal having an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, and means for measuring the speed of rotation of said motor and converting said measurement into an electrical speed signal proportional to said speed and having a polarity indicative of the direction of rotation of said motor, wherein said electronic control circuit further includes an analog multiplier that multiplies the output signal of said integrating servoamplifier and said pressure limit control signal to produce a weighted output signal.

Claim 10

The drive and control circuit of claim 6 wherein said electronic control circuit further comprises a power amplifier that amplifies the output signal of said analog multiplier to produce said output control signal.

Claim 11

The drive and control system according to claim 1 further comprising a proportional actuator that controls the displacement of said motor in response to an electrical displacement control signal.

Claim 12

The drive and control system of claim 1 further comprising a controller that generates said speed and pressure limit control signals.

Claim 13

The drive and control system of claim 9 wherein said controller includes a computer and a multi-channel digital-to-analog converter.

Claim 14

The drive and control system of claim 9 further comprising means for measuring the tension of strand and producing an electrical signal proportional to said measurement.

Claim 15

The drive and control system of claim 11 further comprising an analog-to-digital converter that receives said tension measurement signal and produces a digital output signal for said controller.

Claim 16

The drive and control system of claim 12 further comprising means for measuring the rotational speed of said motor and producing a proportional electrical rotation speed signal that is applied to said analog-to-digital converter.

Claim 17

The drive and control system of claim 1 wherein said regeneration circuit includes means for dividing flow from said return line into a first portion that is directed to said feed line and a second portion that is directed to said supply.

Claim 18

An electrohydraulic drive and control system for linearly traversing a rotatable spool that winds and unwinds an indefinite length of strand material with a constant passline comprising, a hydraulic cylinder that drives said spool linearly along its axis of rotation, first transducer means for sensing the position of said spool and generating an output signal indicative of said position, second transducer means for sensing the linear velocity of said spool and generating an output signal indicative of said velocity, third transducer means for measuring the speed of rotation of said spool and generating an output signal indicative of said rotational speed, electronic controller means for generating a control signal in response to said position, velocity and rotation output signals, preselected values for the limits of said traversing motion and the pitch of said traversing, and a high speed servo-valve responsive to the output control signal of said electronic controller means that controls the operation of said hydraulic cylinder, and means for sensing the lateral position of said strand being wound onto or unwound from said spool and generating an electrical output signal indicative of said strand position.

Claim 19

An electrohydraulic drive and control system for linearly traversing a rotatable spool that winds and unwinds an indefinite length of strand material with a constant passline comprising, a hydraulic cylinder that drives said spool linearly along its axis of rotation, first transducer means for sensing the position of said spool and generating an output signal indicative of said position, second transducer means for sensing the linear velocity of said spool and generating an output signal indicative of said velocity, third transducer means for measuring the speed of rotation of said spool and generating an output signal indicative of said rotational speed, electronic controller means for generating a control signal in response to said position, velocity and rotation output signals, preselected values for the limits of said traversing motion and the pitch of said traversing, and a high speed servo-valve responsive to the output control signal of said electronic controller means that controls the operation of said hydraulic cylinder, and means for sensing the lateral position of said strand being wound onto or unwound from said spool and generating an electrical output signal indicative of said strand position.

Claim 20

The traverse drive and control system of claim 15 further comprising electronic means for generating a control signal for said servo-valve responsive to said strand position signal and said spool velocity signal.

Claim 21

An electrohydraulic drive and control system for rotating and linearly traversing a rotatable spool in coordination to wind and unwind an indefiite length of strand material with a constant passline comprising, a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and said motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than or equal to said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) said speed limit control signal and (iii) said pressure limit control signal, a hydraulic cylinder that drives said spool linearly along its axis of rotation, first transducer means for sensing the position of said spool and generating an output signal indicative of said position, second transducer means for sensing the linear velocity of said spool and generating an output signal indicative of said velocity, third transducer means for measuring the speed of rotation of said spool and generating an output signal indicative of said rotational speed, electronic controller means for generating a control signal in response to said position, velocity and rotation output signals, and preselected values for the limits of said traversing motion and the pitch of said traversing, and a high speed servo-valve responsive to the output control signal of said electronic controller means that controls the operation of said hydraulic cylinder.

Claim 22

An electrohydraulic drive and control system for rotating and linearly traversing a rotatable spool in coordination to wind and unwind an indefiite length of strand material with a constant passline comprising, a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, a feed line and a return line that conduct said fluid between said supply and said motor, a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than or equal to said supply pressure, first means connected in said return line for setting an adjustable fixed pressure in said return line, a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) said speed limit control signal and (iii) said pressure limit control signal, a hydraulic cylinder that drives said spool linearly along its axis of rotation, first transducer means for sensing the position of said spool and generating an output signal indicative of said position, second transducer means for sensing the linear velocity of said spool and generating an output signal indicative of said velocity, third transducer means for measuring the speed of rotation of said spool and generating an output signal indicative of said rotational speed, electronic controller means for generating a control signal in response to said position, velocity and rotation output signals, and preselected values for the limits of said traversing motion and the pitch of said traversing, and a high speed servo-valve responsive to the output control signal of said electronic controller means that controls the operation of said hydraulic cylinder.

Claim 23

The process of controlling a rotating member that engages and controls the speed of and tension in an indefinite length of material in a process line, comprising the steps of providing a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, providing a feed line and a return line that conduct said fluid between said supply and motor, providing a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, providing first means connected in said return line for setting an adjustable fixed pressure in said return line, providing a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, providing a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, providing an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) said speed limit control signal and (iii) said pressure limit control signal, said speed limit control signal being an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, adjusting said variable displacement of the motor to accomodate properties of said material, maintaining said variable displacement substantially constant during rotating engagement of said material; and varying said pressure limit control signal to control the speed of and tension in said material.

Claim 24

The process of controlling a rotating member that engages and controls the speed of and tension in an indefinite length of material in a process line, comprising the steps of providing a supply of hydraulic fluid at a constant supply pressure and variable flow rate, a bi-directional, variable displacement hydraulic motor connected to said rotating member and having an inlet and an outlet for said fluid, providing a feed line and a return line that conduct said fluid between said supply and motor, providing a variable pressure reducing valve connected in said feed line, said valve including a proportional actuator that produces an output flow of said fluid to said motor at a pressure less than said supply pressure, providing first means connected in said return line for setting an adjustable fixed pressure in said return line, providing a hydraulic regeneration circuit connected between said feed line and said return line and operable when said motor brakes, providing a controller that generates (i) a speed limit control signal for limiting the speed of said motor and (ii) a pressure limit control signal related to a maximum desired pressure in said feed line, providing an electronic control circuit that produces an output control signal for said proportional actuator, said circuit being responsive to (i) the speed of rotation of said motor (ii) said speed limit control signal and (iii) said pressure limit control signal, said speed limit control signal being an electrical signal proportional to the desired maximum speed of rotation of said motor and said pressure limit control signal being an electrical signal proportional to the desired maximum pressure in said feed line downstream of said variable pressure reducing valve, adjusting said variable displacement of the motor to accomodate properties of said material, maintaining said variable displacement substantially constant during rotating engagement of said material; and varying said pressure limit control signal to control the speed of and tension in said material.