Tension control method for band saw blade

Abstract

The tension control method comprises the following steps that a driving wheel drives a driven wheel to rotate through the band saw blade, inductive switches are installed on the driving wheel and the driven wheel respectively, and when the driving wheel and the driven wheel rotate, the inductive switches send out pulse signals; two high-speed counters are arranged to respectively record the number of pulse signals sent by the two inductive switches; the linear speed of the driving wheel and the linear speed of the driven wheel are calculated according to the number of the pulse signals recorded in the time period at a certain time interval; and the slip value between the driving wheel and the driven wheel is calculated, and corresponding adjustment is carried out through the value of the slip value.

Description

Technical Field

[0001] The present invention relates to the technical field of tension control, and more specifically, to a method for controlling the tension of a band saw blade. Background Art

[0002] In the forging processing procedure, there is a stock preparation procedure for a processing technology, which requires sawing aluminum bars with a diameter of 8.0 - 10.0 inches into blanks with lengths and weights meeting the process requirements. To complete this procedure operation, a vertical or horizontal band saw or a circular saw is required. For the band saw among them, whether it is a high-speed saw or a low-speed saw, the band saw blade needs to be firmly clamped in the saw blade grooves of the driving and driven band saw wheels of the sawing machine. Excessive or too loose tension during the sawing process will affect the perpendicularity of the sawn blanks, the service life of the band saw blade, and the sawing production rhythm. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a method for controlling the tension of a band saw blade.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] The present invention discloses a method for controlling the tension of a band saw blade, including the following steps:

[0006] Step 1: The driving wheel drives the driven wheel to rotate through the band saw blade. Inductive switches are respectively installed on the driving wheel and the driven wheel. When the driving wheel and the driven wheel rotate, the inductive switches emit pulse signals, and two high-speed counters are set to record the number of pulse signals emitted by the two inductive switches respectively;

[0007] Step 2: At regular intervals, based on the number of pulse signals recorded during this time period, calculate the linear speeds of the driving wheel and the driven wheel;

[0008] Step 3: Calculate the slip value between the driving wheel and the driven wheel. When the slip value exceeds the set range, the driving mechanism controls the driven wheel to move towards the side of increasing tension, that is, towards the side away from the driving wheel; when the slip value is within the set range, the driving mechanism does not move the driven wheel;

[0009] Step 4: Repeat Steps 2 and 3 until the band saw blade stops running.

[0010] Further, the driving wheel is driven by a motor. After the motor starts, the high-speed counter records the pulse signal of the inductive switch on the driving wheel. If continuous pulse signals are not received, it is determined that the motor startup fails or there is a slipping fault in the transmission gear shaft of the gearbox, and corresponding repairs need to be carried out before restarting.

[0011] Further, the set range of the slip value is -5% to +5%.

[0012] Furthermore, the driving mechanism is an oil cylinder, which is drivingly connected to the driven wheel. The oil cylinder is controlled by an electro-hydraulic servo control valve, which has two-way control ability and can control the piston in the oil cylinder to move bidirectionally.

[0013] Furthermore, in step 3, when the slip value is zero, that is, when there is no slip between the driving wheel and the driven wheel, the driving mechanism controls the driven wheel to move towards the side where the tension is reduced, that is, towards the side close to the driving wheel.

[0014] The beneficial effects of the present invention are as follows: the tension of the band saw blade is detected cyclically and adjusted in a timely manner to keep it at an appropriate tension. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the running state of the band saw in this embodiment;

[0016] Figure 2 It is a schematic diagram of a structure of the band saw in this embodiment;

[0017] Figure 3 It is another schematic diagram of a structure of the band saw in this embodiment;

[0018] Figure 4 It is a partial schematic diagram of the adjusting mechanism in this embodiment;

[0019] Figure 5 It is a schematic diagram of a structure of the detection mechanism in this embodiment;

[0020] Figure 6 It is a cross-sectional view of the detection mechanism in this embodiment;

[0021] Figure 7 It is a bottom view of the movable block in this embodiment.

[0022] Reference Numerals: 1, driven wheel; 2, driving wheel; 3, band saw blade; 4, induction switch; 5, high-speed counter; 6, driving mechanism; 7, guide rail; 8, sliding seat; 9, mounting arm; 10, support plate; 11, motor; 12, connecting rod; 13, lead screw; 14, lead screw slider; 15, rotating disk; 16, drive shaft; 17, transmission belt; 18, support frame; 19, sliding groove; 20, sliding block; 21, lever; 22, first spring; 23, detection mechanism; 24, mounting block; 25, sliding hole; 26, support block; 27, pressing block; 28, triggering mechanism; 29, support groove; 30, mounting groove; 31, lifting block; 32, second spring; 33, trigger; 34, movable block; 35, sliding groove; 36, inlet; 37, limiting groove; 38, guiding surface. Detailed Embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] A method for controlling the tension of a band saw blade, comprising the following steps:

[0025] Step 1: The driving wheel drives the driven wheel to rotate through the band saw blade. Inductive switches are respectively installed on the driving wheel and the driven wheel. When the driving wheel and the driven wheel rotate, the inductive switches emit respective independent pulse signals. Two high-speed counters are set to respectively record the number of pulse signals emitted by the two inductive switches.

[0026] Step 2: At intervals of a certain time, specifically, it can be at intervals of 1 - 5 seconds. The linear speeds of the driving wheel and the driven wheel are calculated through the number of pulse signals recorded during this time period. Specifically, when the inductive switch rotates with the driving wheel or the driven wheel, it emits a certain number of pulse signals per revolution. The number of pulse signals recorded during this time period is divided by the number of pulse signals emitted per revolution, and then divided by the time to obtain the rotational speed. The more pulse signals emitted per revolution, the angle of less than one full revolution during this time period can be recorded, and a more accurate number of revolutions can be calculated to reduce errors. It is also possible to increase the number of installed inductive switches, so that multiple pulse signals can be detected within one revolution, and the angle of less than one full revolution during this time period can also be recorded, and a more accurate number of revolutions can be calculated. Then, according to the radius of the wheel, the linear speed is calculated, and the linear speed = 2π × rotational speed × radius.

[0027] Step 3: Calculate the slip value between the driving wheel and the driven wheel. The slip value = (driving wheel linear speed - driven wheel linear speed) / driving wheel linear speed * 100%. When the slip value is not within the set range, the driving mechanism controls the driven wheel to move towards the side of increased tension, that is, towards the side away from the driving wheel. The driving mechanism controls the driven wheel to move at a uniform speed, and the moving speed is 20.0 mm / s.

[0028] When the slip value is within the set range, there are two cases. First, if the previous slip value is also within the set range, the driving mechanism does not act. Second, if the previous slip value is not within the set range, the driving mechanism stops moving the driven wheel.

[0029] Step 4: Repeat Steps 2 and 3 until the band saw blade stops running. Continuously detect the tension of the band saw blade and adjust it in a timely manner to keep it at an appropriate tension.

[0030] Further, the driving wheel is driven by a motor. After the motor starts, the high-speed counter records the pulse signal of the induction switch on the driving wheel. If continuous pulse signals are not received, it is determined that the motor startup fails or the transmission rotating gear shaft slips, and the motor or the transmission needs to be repaired. After the repair is completed, restart it. Under normal circumstances, the driving wheel rotates after the motor starts, and the induction switch on the driving wheel can emit continuous pulse signals.

[0031] Further, the setting range of the slip value is -5% to +5%. The driving wheel and the driven wheel adopt cast wheels with a diameter of 610.0 mm, which tightly wrap the band saw blade to realize the sawing of aluminum bar stock. The two cast wheels run at a linear speed of 90 - 110 meters per minute, and the actual inertia is very large. When stopping or adjusting the speed (decelerating), the speed of the driven wheel may be greater than that of the driving wheel. At this time, the driving pulley is equivalent to the working characteristic of a generator, and negative data of the slip value will appear. Enlarging the measurement range of the speed slip to -5% - 5% is beneficial to the stability and reliability of control.

[0032] Further, the driving mechanism is an oil cylinder. The oil cylinder drives the mounting seat connected to the driven wheel. The oil cylinder is controlled by an electro-hydraulic servo control valve, which has two-way control ability and can control the piston in the oil cylinder to move bidirectionally. The electro-hydraulic servo control valve has a short commutation period and can quickly respond to the requirements of system tension control.

[0033] Further, in step 3, when the slip value is zero, that is, when there is no slip between the driving wheel and the driven wheel, the driving mechanism controls the driven wheel to move towards the side where the tension is reduced, that is, towards the side close to the driving wheel. The driving mechanism controls the driven wheel to move at a constant speed, and the moving speed is 20.0 mm / s. The original tension force is reduced to keep the band saw blade always working at a relatively appropriate tension force.

[0034] Further, an adjusting mechanism for the high-speed counter 5 is provided. When the rotation speed of the driving wheel 2 increases, the adjusting mechanism can reduce the distance between the high-speed counter 5 and the driven wheel 1 and the driving wheel 2, so that the high-speed counter 5 can accurately record the number of pulse signals emitted by the induction switch 4 on the driven wheel 1 and the driving wheel 2.

[0035] As Figure 1 、 Figure 2 shown, the band saw includes a driven wheel 1 and a driving wheel 2. A band saw blade 3 is connected between the driven wheel 1 and the driving wheel 2 for transmission. Induction switches 4 are installed on the driving wheel 2 and the driven wheel 1. A high-speed counter 5 is installed in the extending direction of the center line connection of the induction switch 4 and the driven wheel 1 and the driving wheel 2. The high-speed counter 5 is used to record the number of pulse signals emitted by the induction switch 4. The driving mechanism 6 can drive the driven wheel 1 to move away from or close to the driving wheel 2, so that the band saw blade 3 maintains an appropriate tension.

[0036] As shown Figures 3 - 7 in the figure, the band saw further includes an adjusting mechanism, and the adjusting mechanism can adjust the distance between the high-speed counter 5 and the driven wheel 1 and the driving wheel 2 as the rotation speed of the driving wheel 2 changes.

[0037] The adjusting mechanism includes a support plate 10. A guide rail 7 is arranged on the support plate 10. A sliding seat 8 is slidably arranged on the guide rail 7. An installation arm 9 is installed on the sliding seat 8. The high-speed counter 5 is installed on the installation arm 9. A motor 11 is arranged on the support plate 10. The motor 11 is drivingly connected to a lead screw 13. A lead screw slider 14 is installed on the lead screw 13. A connecting rod 12 is connected between the two installation arms 9. The connecting rod 12 is installed on the lead screw slider 14. By starting the motor 11 to drive the connecting rod 12 to move, the position of the installation arm 9 is adjusted, so as to adjust the distance between the high-speed counter 5 and the driven wheel 1 and the driving wheel 2. When the rotation speed of the driving wheel 2 increases, the high-speed counter 5 is made to approach, and the pulse signal sent by the induction switch 4 can be recorded more accurately.

[0038] As shown Figure 4 in the figure, the adjusting mechanism includes a rotating disk 15. A driving shaft 16 is connected at the center position of the rotating disk 15. The driving shaft 16 is in belt and pulley transmission with the driving wheel 2 through a transmission belt 17. The rotation speed of the rotating disk 15 increases as the rotation speed of the driving wheel 2 increases. A sliding groove 19 is formed on the rotating disk 15. The sliding groove 19 is arranged along the radial direction of the rotating disk 15. A sliding block 20 is slidably arranged in the sliding groove 19. One end of the sliding block 20 far away from the center of the rotating disk 15 is connected to a first spring 22. The other end of the first spring 22 is connected to the outer side wall of the sliding groove 19. A lever 21 is connected to the upper part of the sliding block 20. The lever 21 is perpendicular to the sliding block 20. As the rotation speed of the rotating disk 15 increases, the sliding block 20 will move outward along the sliding groove 19 due to centrifugal force. The faster the rotation speed of the rotating disk 15, the farther the sliding block 20 is from the center of the rotating disk 15.

[0039] A support frame 18 is arranged above the rotating disk 15. A detection mechanism 23 is installed on the support frame 18. The detection mechanism 23 is embedded in the support frame 18. The detection mechanism 23 can be used to detect the position of the lever 21, that is, it can detect whether the rotation speed of the rotating disk 15 increases. Specifically, the detection mechanism 23 includes a mounting block 24. A sliding hole 25 is formed in the mounting block 24. The sliding hole 25 is arranged along the radial direction of the rotating disk 15. A support block 26 is arranged in the sliding hole 25. A part of the support block 26 is located above the mounting block 24. The lower end of the support block 26 passes through the sliding hole 25 and is connected to a movable block 34. A sliding groove 35 is formed in the lower part of the movable block 34. A pressing block 27 is connected to the side of the support block 26. A plurality of trigger mechanisms 28 are arranged at the position corresponding to the lower part of the pressing block 27 on the mounting block 24. The plurality of trigger mechanisms 28 are arranged along the length direction of the sliding hole 25. The trigger mechanism 28 is electrically connected to the motor 11.

[0040] During the process of the rotating disk 15 rotating to drive the sliding block 20 to rotate, the lever 21 will pass through the sliding groove 35 in the movable block 34. After the distance between the lever 21 and the center of the rotating disk 15 changes, when passing through the sliding groove 35, it will contact the sliding groove 35 to drive the movable block 34 to move. The movable block 34 drives the support block 26 to move, so that the pressing block 27 contacts the corresponding trigger mechanism 28 to send a signal. When the newly triggered trigger mechanism 28 is farther from the center of the rotating disk 15 than the triggered trigger mechanism 28, it indicates that the rotation speed of the rotating disk 15 increases, that is, the rotation speed of the driving wheel 2 increases. At this time, control the motor 11 to make the high-speed counter 5 move towards the driving wheel 2 and the driven wheel 1, reducing the distance between the high-speed counter 5 and the induction switch 4, so that the high-speed counter 5 can better record the pulse signal sent by the induction switch 4, reducing the interference caused by the excessive distance between the two and affecting the counting, and avoiding affecting the detection result. When the newly triggered trigger mechanism 28 is farther from the center of the rotating disk 15 than the triggered trigger mechanism 28, it indicates that the rotation speed of the rotating disk 15 decreases, that is, the driving wheel 2 starts to decelerate and prepare to stop. At this time, control the motor 11 to make the high-speed counter 5 move away from the driving wheel 2 and the driven wheel 1, maintaining sufficient space between the high-speed counter 5 and the driving wheel 2 and the driven wheel 1, so as not to affect the operation of the staff.

[0041] As Figure 6 shown, the trigger mechanism 28 includes an installation groove 30 opened on the installation block 24. An elevating block 31 is installed in the installation groove 30. A part of the elevating block 31 is located in the installation groove 30, and a part of it penetrates out of the installation groove 30. The upper end of the elevating block 31 is hemispherical. A second spring 32 is connected between the lower end of the elevating block 31 and the bottom of the installation groove 30. A trigger 33 is provided at the bottom of the installation groove 30. Guide surfaces 38 are provided at positions near both sides of the lower end surface of the pressing block 27. The guide surfaces 38 are inclined outward and upward. During the movement of the pressing block 27, the guide surfaces 38 can press down the elevating block 31, so that the lower end surface of the pressing block 27 further presses down the limiting groove 37 to make the bottom of the limiting groove 37 contact the trigger 33. A limiting groove 37 is opened on the lower end surface of the pressing block 27. The shape of the limiting groove 37 matches the shape of the top of the elevating block 31. The top end of the elevating block 31 can extend into the limiting groove 37, so that the limiting groove 37 can limit the position of the pressing block 27 to a certain extent, so that the movable block 34 will not shake and shift to affect the control. At the same time, when the lever 21 acts on the sliding groove 35 to make the movable block 34 move, the elevating block 31 can be disengaged from the limiting groove 37 without causing interference.

[0042] A support groove 29 is opened at the upper end of the installation block 24. The support groove 29 is arranged along the length direction of the sliding hole 25. A ball is installed at the lower part of the support block 26, and the lower part of the ball is located in the support groove 29.

[0043] The two ends of the sliding groove 35 are respectively provided with guiding inlets 36. The distance between the two side edges of the guiding inlet 36 gradually increases as it moves away from the sliding groove 35. The setting of the guiding inlet 36 can guide the shifting lever 21 to better enter the sliding groove 35. The guiding inlet 36 is in a horn shape, so that the shifting lever 21 can be guided by the guiding inlet 36 during the process of moving away from or approaching the center of the circle.

[0044] The above description is only the preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. Any technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for controlling the tension of a band saw blade, characterized in that: Step 1: The driving wheel (2) drives the driven wheel (1) to rotate through the band saw blade (3), and the driving wheel (2) and the driven wheel (1) are respectively installed with induction switches (4). When the driving wheel (2) and the driven wheel (1) rotate, the induction switches (4) send out pulse signals, and two high-speed counters (5) are set to respectively record the number of pulse signals sent by the two induction switches (4); Step 2: At a certain time interval, the linear speeds of the driving wheel (2) and the driven wheel (1) are calculated by the number of pulse signals recorded in the time period; Step 3: Calculate the slip value between the driving wheel (2) and the driven wheel (1). When the slip value exceeds a set range, the driving mechanism (6) controls the driven wheel (1) to move toward the side of increasing the tension. When the slip value is within the set range, the driving mechanism (6) does not move the driven wheel (1). Step 4: Repeat steps 2 and 3 until the band saw blade (3) stops running.

2. A band saw blade tension control method according to claim 1, characterized in that: The driving wheel (2) is driven by a motor. After the motor is started, the pulse signal of the induction switch (4) on the driving wheel (2) is recorded by a high-speed counter (5). If no continuous pulse signal is received, it is determined that the motor fails to start or the gear shaft of the gearbox slips.

3. A band saw blade tension control method according to claim 1, characterized in that: The slip value can be set between -5% and +5%.

4. A band saw blade tension control method according to claim 1, characterized in that: The driving mechanism (6) is an oil cylinder, which is connected to the driven wheel (1) by driving. The oil cylinder is controlled by an electro-hydraulic servo control valve. The electro-hydraulic servo control valve has a bidirectional control capability and can control the bidirectional movement of the piston in the oil cylinder.

5. A band saw blade tension control method according to claim 1, characterized in that: In step 3, when the slip value is zero, the driving mechanism (6) controls the driven wheel (1) to move toward the side where the tension is reduced.

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