JPS63187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tube cutting device, and more particularly to a tube cutting device using a disc-shaped grindstone.

When cutting a tube, the tube is usually supported horizontally by support rollers and rotated at low speed, and a high-speed rotating disc-shaped grindstone installed at the tip of a swinging arm is pressed against the tube from below. It is customary to apply the cutting depth and feed by adjusting the cutting angle. By the way, when cutting a workpiece with a disc-shaped grindstone, in order to increase the cutting efficiency, it is necessary to keep the circumferential speed of the grindstone constant. Therefore, in order to control the circumferential speed, it is first necessary to know the diameter of the grinding wheel. Conventionally, a worker approaches the equipment and measures it, or determines the diameter of the grinding wheel using some kind of guide, and then manually sets the circumferential speed of the grinding wheel based on this, but this method lacks safety and reliability. There is a problem. In addition, even if you attempt to indirectly measure the diameter of the grinding wheel from changes in the weight of the grinding wheel, the change in weight of the grinding wheel is small compared to the weight of other movable parts, so it is unreliable.
Furthermore, direct measurement using an optical sensor also has the problem of poor reliability due to a decrease in sensor performance due to adhesion of chips and dust during cutting.

Therefore, the present invention corrects the drawbacks of the above-mentioned prior art, and
The purpose of this invention is to enable the diameter of the grindstone to be measured safely and with high reliability, and to control the circumferential speed of the grindstone at a constant speed according to the diameter of the grindstone based on the results.

In order to achieve this object, the present invention includes a disc-shaped grindstone that is attached to one end of a swinging arm that swings in the vertical direction and is capable of cutting a horizontally supported pipe by coming into contact with it from below; a weight body attached to the other end of the swinging arm and capable of generating a moment to move the disc-shaped grindstone upward; and a weight body suspended at a distance from the weight body and pressed from below. A hanging weight body which, when lifted, releases the suspended state and comes into contact with the lower surface of the weight body; and a suspended weight body which is brought into contact with the weight body and both weight bodies are brought into contact with the bottom surface of the weight body. and by this pushing up, the rocking arm is swung to lower the grindstone to a predetermined standby position below the tube, and both weight bodies are lowered while supporting both weight bodies, a lifting drive device that raises the grindstone from a predetermined standby position to a position where it contacts the pipe; and after the raised grindstone contacts the pipe, the suspended weight is lowered so that the suspended weight becomes a weight. a detection means for detecting separation from the grinding wheel, and an amount of displacement of the grinding wheel from the predetermined standby position to a contact position of the grinding wheel and the pipe based on the amount of movement of the lifting drive device when the detection means operates. Displacement amount measuring means; Grinding wheel diameter calculating means for calculating a grinding wheel diameter from this displacement amount; Drive power determining means for determining the driving power of a grinding wheel driving device necessary to obtain a required circumferential speed of the grinding wheel from this grinding wheel diameter. It is equipped with the following.

According to such a configuration, the diameter of the grinding wheel is determined by the amount of displacement of the grinding wheel from a predetermined standby position until it comes into contact with the pipe, and the required circumferential speed corresponding to this diameter is given to the grinding wheel. .

Examples of the present invention will be described below.

As shown in FIG. 1, a disc-shaped grindstone 3 capable of cutting the pipe 2 by abutting it from below on the pipe 2 supported in the horizontal direction by a roller 1 is provided at one end of the swinging arm 4. A displacement detection device 8 detects the displacement of the grinding wheel 3 from a predetermined standby position 6 below the tube 2 to a contact position 7 with the tube 2 by contacting a weight 5 attached to the other end of the grinding wheel 3. Displacement amount measuring means 9 is provided to measure this amount of displacement based on a signal, and grinding wheel diameter calculating means 10 is provided to calculate the diameter of the grinding wheel 3 from this amount of displacement.
A drive power determining means 12 is provided for determining the drive power of the grindstone driving device 11 necessary to obtain the required circumferential speed of the grindstone 3 from the diameter of the grindstone.

In FIG. 1, reference numeral 13 denotes a grindstone wear calculation means for calculating the grindstone wear amount during the previous cutting operation from the previous grindstone diameter and the current grindstone diameter calculated by the grindstone diameter calculation means 10. . Further, reference numeral 14 is designed to keep the circumferential speed of the grindstone 3 constant regardless of changes in the diameter of the grindstone during cutting, as the grindstone 3 naturally wears out during the cutting of the pipe and its value directly changes. This is a power correction means that corrects the output from the drive power determination means 12.

The displacement amount measuring means 9, the grinding wheel diameter calculating means 10,
Drive power determining means 12, grinding wheel wear amount calculating means 13
The functions of the power correction means 14 are achieved by the microcomputer 15. FIGS. number, and the explanation thereof will be omitted. The weights 5 include a fixed weight 16 as a weight fixed to the swinging arm 4, a first hanging weight 17 also as a weight suspended from the fixed weight 16, and a first hanging weight. 17 and a second hanging weight 18 as a hanging weight body.

The fixed weight 16 and the first hanging weight 17 are capable of generating a moment that moves the grindstone 3 upward. The second hanging weight 18 is released from the suspended state by being pushed up from below and can come into contact with the first hanging weight 17 .

On the other hand, the displacement detection device 8 includes the first and second hanging weights 17 and 18, and
It has a ball screw jack 19 as an elevating drive device that can come into contact with the second hanging weight 18. 20 is a motor with a brake for driving the jack 19, and 21 is a rotary encoder, which detects the rotation angle of the motor 20 to control the jack 19, the weight 5, and the swing arm 4.
The amount of displacement of the grindstone 3 can be detected through the . Further, the second hanging weight 18 is provided with a limit switch 22 as a detection means, and the first hanging weight 17 is provided with a limit switch 22 as a detection means. A locking piece 23 that sometimes turns on the limit switch 22
is provided. The grindstone driving device 11 includes a motor 24 for rotationally driving the grindstone 3 and a tachometer generator 25 for detecting the number of rotations of the motor 24.

FIG. 4 shows the overall hardware configuration of the present invention. That is, the cutting machine control panel 26 is configured to receive an on/off signal from the limit switch 22, a detection signal from the rotary encoder 21, and output driving power for the motor 20 with a brake. Also 2
7 is a control panel for the motor 24, which receives signals from the tachogenerator 25 and also controls the motor 24.
It is configured to output driving power of .

The control microcomputer 15 has an interface 28 with control panels 26 and 27. 29 is a tachometer generator 25 and a motor 2
Input/output line with 4, 30 is limit switch 2
2, and 31 is an input/output line to the rotary encoder 21 and the motor 20 with a brake. Further, 32 is a CPU, 33 is a memory, and 34 is a keyboard.

Next, the operation will be explained based on the flowchart shown in FIG. Prior to the work, the diameter value of the tube 2 to be cut is inputted using the keyboard 34. FIG. 2 shows the initial state before the start of cutting. That is, the jack 19 pushes up the second hanging weight 18, and the second hanging weight 18
The first hanging weight 17 and fixed weight 16 are pushed up, and the grindstone 3 is lowered to a predetermined standby position 6 below the tube 2. At this time, the rotary encoder 21 detects that the grindstone 3 is at the predetermined standby position 6, and since the second hanging weight 18 is in contact with the first hanging weight 17, the limit switch 22 is activated. It is in the on state.

From this state, the jack 19 is driven to gradually lower the weight 5. Then, the grinding wheel 3 gradually rises, and the displacement from position 6 is read by the rotary encoder 21. As shown in FIG. 1, when the grinding wheel 3 reaches the contact position 7 with the tube 2, the lifting of the grinding wheel 3 is stopped, and the fixed weight 16 and the first hanging weight 17
The descent of will also be stopped. However, the jack 19 is still operating, and only the second hanging weight 18 continues to descend, and this second hanging weight 18
The limit switch 22 is turned off when it is separated from the hanging weight 17. This timing is read by the microcomputer 15, and based on the reading of the rotary encoder 21 at this time, the amount of displacement of the grindstone 3 from the predetermined standby position 6 to the contact position 7 is measured.

The diameter of the grinding wheel is calculated from this displacement amount and the diameter value of the tube 2 mentioned above, and the circumferential speed of the grinding wheel 3 is set to a predetermined value.
A drive power signal for rotation speed control to the motor of the grindstone drive device 11 is determined.

Further, the diameter of the grindstone at the start of cutting during the previous cutting is stored in the memory 33, and the wear amount of the grindstone 3 during the previous cutting is calculated by comparing the grindstone diameter values of the previous time and this time. Several types of curves of wear over time of the grinding wheel 3 based on differences in characteristics are measured in advance (three types in the one shown in Fig. 5), and the curves are measured in response to changes in the diameter of the grinding wheel 3 during cutting. A time-varying power correction signal is applied to the rotational speed control drive power signal so that the circumferential speed always remains at a constant value.

The motor 24 is driven by such a signal,
The tube 2 is cut as shown in FIG. 3 while reading the rotational speed of the motor 24 with the tachometer generator 25. At this time, the jack 19 has been lowered to a predetermined lower position 35 away from the second hanging weight 18, and all the weights 16, 1
The weights 7 and 18 act to create a cut.

When the cutting of the tube 2 is completed, the reaction force from the tube 2 disappears, the grindstone 3 moves upward, and the weight 1
6, 17, and 18 are all supported by the jack 19 at the predetermined position 35. This turns on the limit switch 22 again,
Based on this signal, a stop signal for the motor 24 is issued. At the same time, the jack 19 is raised and the grindstone 3 is returned to the predetermined standby position 6 shown in FIG. 2, completing one cycle of work.

As described above, according to the present invention, the diameter of the disc-shaped grinding wheel can be adjusted in a safe and highly reliable manner based on the amount of displacement of the disc-shaped grinding wheel from the predetermined standby position to the abutment position of the disc-shaped grinding wheel and the pipe. Not only can it be measured with
Based on this measurement result, the grindstone can be controlled to always have a constant circumferential speed, and the grindstone can be constantly operated under good conditions.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of the present invention, Figs. 2 and 3 are diagrams showing a schematic configuration diagram of the mechanical device, Fig. 4 is a diagram showing the overall configuration of the hardware, and Fig. 5 is a flowchart of the operation. FIG. 2...tube, 3...disc-shaped grindstone, 4...swinging arm,
6... Predetermined standby position, 7... Contact position, 9... Displacement amount measuring means, 10... Grinding wheel diameter calculating means, 11...
... Grinding wheel drive device, 12 ... Drive power determining means, 1
3... Grindstone wear amount calculation means, 14... Power correction means.

Claims (1)

[Scope of Claims] 1. A disc-shaped grindstone attached to one end of a swinging arm that swings vertically and capable of cutting a horizontally supported pipe by coming into contact with it from below, and the swinging arm. a weight body attached to the other end and capable of generating a moment to move the disc-shaped grindstone upward; and a weight body suspended at a distance from the weight body and pushed up from below. a suspended weight body that is brought into contact with the lower surface of the weight body when the suspended state is released; and the suspended weight body is brought into contact with the weight body and both weight bodies are pushed up together; This push-up causes the swinging arm to swing and lower the whetstone to a predetermined standby position below the tube, and also lowers both weight bodies while supporting both weight bodies to lower the whetstone. A lifting drive device raises the grindstone from a predetermined standby position to a position where it contacts the pipe, and after the raised grindstone contacts the pipe, the suspended weight is lowered and the suspended weight is separated from the weight. a detection means for detecting this; and a displacement measurement means for measuring the displacement of the grindstone from the predetermined standby position to the contact position with the pipe based on the amount of operation of the lifting drive device when the detection means operates. , a grinding wheel diameter calculation means for calculating a grinding wheel diameter from this displacement amount, and a driving power determining means for determining a driving power of a grinding wheel driving device necessary to obtain a required circumferential speed of the grinding wheel from this grinding wheel diameter. A tube cutting device characterized by: