Cable tension control device
A cable tension control device includes a pair of first active rollers clamping a cable therebetween, a first driver driving the first active rollers, a pair of second active rollers clamping the cable therebetween at an upstream position from the first active rollers, a second driver driving the second active rollers, a floating roller arranged between the first active rollers and the second active rollers and exerting a pushing force on the cable, and an actuator driving the floating roller to move vertically to adjust the pushing force exerted on the cable. A tension force applied on the cable is controlled to be equal to a predetermined tension force by controlling the pushing force and by controlling a speed difference between a first speed at which the first active rollers convey the cable forward and a second speed at which the second active rollers convey the cable forward.
1. A cable tension control device, comprising:
a pair of first active rollers clamping a cable therebetween;
a first driver driving the first active rollers to rotate so as to convey the cable forward;
a pair of second active rollers clamping the cable therebetween at an upstream position from the first active rollers;
a second driver driving the second active rollers to rotate so as to convey the cable forward;
a floating roller arranged between the first active rollers and the second active rollers and exerting a pushing force on the cable; and
an actuator driving the floating roller to move vertically to adjust the pushing force exerted on the cable, a tension force applied on the cable is controlled to be equal to a predetermined tension force by controlling the pushing force and by controlling a speed difference between a first speed at which the first active rollers convey the cable forward and a second speed at which the second active rollers convey the cable forward.
2. The cable tension control device according to claim 1 , wherein, if the tension force applied on the cable is equal to the predetermined tension force and the pushing force exerted on the cable is equal to a predetermined pushing force, the speed difference between the first speed and the second speed is equal to a predetermined speed difference.
3. The cable tension control device according to claim 2 , wherein the first active rollers and the second active rollers are located at a same height position.
4. The cable tension control device according to claim 3 , wherein the floating roller is located at a middle position between the first active rollers and the second active rollers.
5. The cable tension control device according to claim 2 , further comprising a sensor provided on the actuator.
6. The cable tension control device according to claim 5 , wherein the sensor detects a movement amount of the floating roller in a vertical direction.
7. The cable tension control device according to claim 5 , further comprising a controller adjusting and controlling a driving force of the actuator.
8. The cable tension control device according to claim 7 , wherein the controller adjusts and controls the driving force according to a movement amount detected by the sensor, such that the pushing force is equal to the predetermined pushing force.
9. The cable tension control device according to claim 2 , wherein, if the tension force applied on the cable is equal to the predetermined tension force, the first speed is greater than the second speed and the first speed is equal to a predetermined cable conveying speed.
10. The cable tension control device according to claim 1 , wherein the first active rollers and the second active rollers are located at a same height position.
11. The cable tension control device according to claim 10 , wherein the floating roller is located at a middle position between the first active rollers and the second active rollers.
12. The cable tension control device according to claim 1 , wherein the first driver and the second driver are electric motors.
13. The cable tension control device according to claim 1 , wherein the actuator is an air cylinder, a hydraulic cylinder, or a servo motor.