JPS6018249Y2 - cutting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting device for cutting a pipe or plate into a predetermined length while moving at a predetermined speed.

This type of cutting device is used to cut continuously manufactured pipes or plates moving at a predetermined speed to a predetermined length while the pipe or plate is moving.

Especially for this cutting device, the cutting blade is initially stationary.
When a pipe or the like to be cut approaches, the cart or the like equipped with the cutting blade quickly adjusts its speed in the moving direction of the object to be cut, such as the pipe, and when the speed reaches the same speed, the cutting is performed. .

FIG. 1 illustrates the relationship between the object to be cut and the cutting blade, with the horizontal axis representing time and the vertical axis representing speed.

In FIG. 1, time t indicates the point at which the cutting blade is at rest, the point at which the cutting blade is cutting, or the solid line A indicates the speed of the cutting blade, and the dashed line B indicates the moving speed of the object to be cut, such as a pipe.

As is clear from FIG. 1, the cutting blade starts cutting when it quickly reaches the speed B of the object to be cut (point C in the figure).

The length of the object to be cut in this way can be considered as follows.

In other words, the moving distance L1 of the object to be cut (rectangles X, Y, and C in Fig.
, Z) and the moving distance L2 of the cutting blade between the time when the cutting blade starts and the cutting operation is performed (triangles X and C in FIG. 1).

The accuracy of the cutting length is determined from the difference (LI L2) from the Z (proportional to the area of Z).

This cutting length has already moved since the previous cutting, so the cutting length is the length that has been lengthened by (l, 1-L2). be done.

Since the object to be cut is cut as described above,
To maintain high cutting length accuracy, the cutting blade must quickly match the speed of the workpiece at point C in Figure 1, and the length (LI L2) must be kept highly accurate each time. need to be

Here, since the speed of the object to be cut, such as a pipe, can usually be easily maintained with high precision, the above-mentioned relationship (LL-L2)÷h holds true.

Therefore, if even the value of h, that is, the moving distance of the cutting blade, can be obtained with high precision each time, it is possible to maintain high precision of the cutting length.

However, in the past, it was extremely difficult to maintain this high level of accuracy.

The present invention was developed in view of the above circumstances, and aims to provide a cutting device that can maintain the moving distance of the cutting blade with high accuracy each time and reliably cut the object to be cut to a fixed size. .

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 1 indicates an object to be cut, such as a pipe, and this object 1 is moving at a predetermined speed in the direction of an arrow 2 in the figure.

3 is a first pulse generator for obtaining the moving speed of the object to be cut 1, that is, the moving distance of the object to be cut;
The output of the pulse generator 3 is applied to a function generator 5 via an F/V converter 4 and also to a down terminal of a first reversible counter 6.

The output of a second pulse generator, which will be described later, is applied to the up terminal of the first reversible counter 6.

Reference numeral 7 denotes a length setting device for setting the cutting length of the object to be cut 1. The output of this setting device 7 is given to a first reversible counter 6, and this counter 6 compares the set output with the input value given to the terminal. The counter 6 outputs the difference between the set output and the input value.

This output is compared with the output of the output setter 8a of the cutting length set in advance by the first comparator 8, and when the output of the counter 6 reaches a value, the start relay 9 is energized by the comparison output. Then, a relay output is given to the function generator 5.

Then, the function generator 5 starts its operation and provides an output to the speed control device 10.

The output of this device 10 starts a DC motor 12 that drives a cutting machine 11.

The timing at which the cutting machine 11 is started is shown in FIGS. 3A to 3C.

When the electric motor 12 is started, the output of the second pulse generator 13 (the moving distance 'L2) is input to the up terminal of the first reversible counter 6.

The difference between the first reversible counter 6 and the output of the first pulse generator 3 (L1-L2) is inputted into the instantaneous memory 14.

The output of the second pulse generator 13 is supplied to a second reversible counter 15, and the output thereof is supplied to a second comparator 16.

This second comparator 16 is a setter 1 for the moving speed of the object 1 to be cut.
The comparison output with the output of 7 is given to the instantaneous memory 14.

The memory 14 takes the difference between the output of the first reversible counter 6 and the output of the second comparator 16.

This difference output is converted into a pulse by a pulse converter 18, and the third
It is input to the reversible counter 19.

The output of this counter 19 is sent to the digital-to-analog converter 2.
0.

This digital-to-analog converter 20 converts the electric motor 12 into a
Since there is no need to modify the speed of the function generator 5, the correction command value given to the function generator 5 is set to zero.

The acceleration characteristics of the cutting machine 11 at this time are shown in Fig. 3, and the amount of movement of the cutting machine 11 is shown in Fig. 4.

The reason why the amount of movement of the cutting machine 11 in FIG. 4 draws a parabola is because of the way the triangles x, y, and c in FIG. 1 increase with respect to time.

As mentioned above, when the speed of the cutting machine 11 and the moving speed of the object to be cut 1 match and the object to be cut 1 reaches the set cutting length, the third
From the relationship between the output of the first reversible counter 6 given to the comparator 21 and the output of the cutting length zero setter 22, the third
An output is generated from the comparator 21, which energizes the cut command relay 23 to provide a cut command to the cutting blade 24 of the cutting machine 11.

The cutting length zero setting device 22 sets the cutting length of the workpiece 1 set by the output setting device 8a to, for example, r15or/
rIn, the set cutting length of the object 1 to be cut is exactly r150mmJ' 150mm-150
This is a setting device for setting that the length is Omm, that is, I″OwnJ (cutting length).

By providing this setting device 22, the length of the object 1 to be cut can be cut accurately.

When the cutting of the object 1 is completed, a cut end command is given to the function generator 5.

Then, a reversal command is given to the electric motor 12 from the function generator 5, and the cutting machine 11 is quickly returned to its initial position.

While this electric motor 12 is in reverse rotation, the signal connected to the up terminal of the first reversible counter 6 (not shown) is operated down, and is reset at the time of completion of cutting, and at the same time, the signal connected to the up terminal of the first reversible counter 6 is continuously transmitted to the counter 6, which is set to a predetermined length. record the length of the cut object.

Additionally, pulse converter 18 prevents motor 12 from operating during reversal.

Next, if the moving speed of the cutting machine 11 is faster than the speed of the object to be cut 1 as shown in Figure 3a, if the object to be cut 1 is cut in this state, the cut length will be shorter than the above. I end up.

Therefore, in the above case, the difference in the first reversible counter 6 becomes larger than in the above case and is stored in the instantaneous memory 14.

On the other hand, the output of the second reversible counter 15 also changes and the second
The difference with the comparator 16 becomes large, and this difference becomes the instantaneous memory 1
4 will be compared.

That is, since the solid line shown in FIG. 4a is the amount of movement of the cutting machine 11, the output is sent from the third reversible counter 19 by the number of pulses proportional to the amount of the arrow in FIG. 4a.

The output of this counter 19 is sent to the digital-to-analog converter 2.
0, it is converted to an analog quantity, and with this analog quantity, Figure 3 a
The motor 12 is decelerated so that the speed is as indicated by the dotted line in FIG. 3a or the dotted line in FIG. 4a.

This is because when the analog quantity is given to the function generator 5, an acceleration reduction command is given from the function generator 5 to the electric motor 12 via the speed control device 10.

Next, if the speed of the cutting machine 11 is too slow, the result will be as shown by the solid line in FIG. 3C.

Therefore, the difference between the output of the first reversible counter 6 and the output of the second comparator 16 is large, as shown by the solid line in FIG. 4C (dotted line).

This difference is compared in the instantaneous memory 14 as before, and as before, this time the number of pulses proportional to the arrow in FIG.
The output of analog converter 20 is provided to function generator 5.

The function generator 5 gives an acceleration increase command to the electric motor 12 via the speed control device 10.

In this way, the moving acceleration of the cutting machine 11 can be adjusted to
Even if the moving speed differs from the moving speed, a correction command for decelerating or increasing the acceleration is given, so that the object 1 to be cut can always be cut at a constant length.

In addition, in the above explanation, we have described the case where all the correction amounts etc. are cleared when one cutting is completed, but if the correction amounts are accumulated in the third reversible counter 19, for example, and the accumulated amount is The correction may be performed using an integral amount.

Up to now, we have described the correction amount and the fact that the acceleration correction is applied after the cutting machine 11 is started using 17.
In FIG. 2, the digital-to-analog converter 20 is omitted, and instead, the output of the third reversible counter 19 is directly input.
Even if the setting device 8a is supplied as a command value correction for the setting device 8a which is operating as a cutting machine movement start setting device, the same operation as in the embodiment described above can be achieved.

In this way, even if the moving acceleration of the cutting machine 11 is the same, the starting point will be corrected, and it will be possible to always cut the cutting length to a constant length even in cases such as those shown in Fig. 3 a and c. be.

As described above, according to the present invention, the object to be cut can be cut to a constant length extremely accurately and continuously, and even if the moving speed of the halfway cutter varies, the amount of correction corresponding to this variation is A cutting device that can always cut a workpiece into two constant lengths without causing the cutting length to be long or short can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining the operation of the cutting device, Fig. 2 is a configuration diagram showing an embodiment of the present invention, and Fig. 3 a ``-'
C and FIGS. 4A to 4C are explanatory diagrams for describing the operation of the present invention. 1...Object to be cut, 3...First pulse generator, 5...Function generator, 6...First
Reversible counter, 7... Cutting length setting device,
8...First comparator, 10... Speed control device, 11... Cutting machine, 12... DC motor, 13... Second pulse generator, 14...
...Momentary memory, 15...Second reversible counter, 16...Second comparator, 17...
... Setting device, 19 ... Third reversible counter, 20 ... Digital-to-analog converter, 2
1... Third comparator, 24... Cutting blade.

Claims (1)

[Scope of Claim for Utility Model Registration] A cutting device that is connected to a device in which a cutting blade moves back and forth in a straight line so as to cut an object to be cut, such as a pipe or plate, into a predetermined length while moving at a predetermined speed. first and second pulse generators that indicate the respective travel distances of the cutting object and the cutting blade; the output of the first pulse generator is applied to the down terminal and the output of the second pulse generator is applied to the up terminal, and a first reversible counter to which the difference between the output and the output of a length setting device for setting the cutting length of the object to be cut is sent; and a difference output from this counter and an output setting device for setting a preset cutting length; a first comparator that compares outputs and sends out an output when the difference output of the counter reaches a predetermined value;
The output of the pulse generator is applied to a second reversible counter, a second comparator that compares the output of the counter with the output of a setting device for the moving speed of the object to be cut; an instantaneous memory to which the output of the counter is input and the difference output is sent to the output; a function generator to which the output of the first pulse generator is supplied and starts operating with the output of the first comparator; A speed control device that is controlled by the output of a function generator and controls the moving speed of the cutting blade and the difference output from the instantaneous memory are input, and the moving speed of the cutting blade and the moving speed of the object to be cut are set to the cutting length. a third reversible counter that sends an output that causes the function generator to change the correction command value of the cutting length, and an output of the first reversible counter and an output of the cutting setter, except that the function generator is optimal for the cutting length. a third comparator that sends a cut command to the cutting blade when the moving speeds of the cutting blade and the object to be cut match and the set cutting length of the object to be cut is reached; A cutting device characterized in that it provides a correction for.