JPH06304682A - Device for detecting abnormality of feeding press material - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a simple and highly accurate press material feeding abnormality detection device. [Structure] In an apparatus for intermittently supplying the press material (5) by sandwiching it by two rolls (3, 4) for each stroke of the press machine, one encoder (related to the drive side feed roll (3) ( 1) and another encoder (2) related to the material to be fed (5), a total of two encoders are provided, said one encoder (1) being set in the material transfer device itself The number of pulses corresponding to the transfer distance is detected, and the other encoder (2) is configured to detect the number of pulses corresponding to the actual moving distance of the material (5), and both pulse numbers are being transferred. A feed abnormality detection device that counts with a counter and outputs a feed abnormality signal when the difference exceeds a predetermined value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press material feed abnormality detecting device, and more specifically, it can detect with high accuracy when a predetermined feed has an abnormality due to material slip or the like. The present invention relates to an anomaly detection device having a simple structure and relatively low cost.

[0002]

2. Description of the Related Art Normally, whether or not a press material is accurately fed by a set amount is detected by measuring the position of the material at the completion of feeding by using a pilot pin or a light beam type sensor, and it is determined that there is no abnormality. For example, the feed abnormal signal is first issued at this point to stop the press suddenly, and this method is still common today. However, if the abnormality is detected when the feeding is completed, a situation occurs in which the material is not normally fed and punching occurs, which causes damage to the die. Most of the damage of the die during the press operation occurs in such a situation.

In order to avoid such an adverse effect, Japanese Patent Laid-Open No. Sho 61-61
-266137 "Press material feed abnormality detection device of press" sets a plurality of detection points that hold the press material feed amount and compare it with the reference value from the feed start period to the end period. Inventions for early detection of mistakes have been proposed. Specifically, in this disclosed invention, the target of comparison with the measured material feed amount (“measured feed amount”) is “corresponding to the stored press material feed amount and the output timing of each synchronization signal. It is defined as "a preset feed amount of press material". Explaining the operation of the disclosed invention as a specific example, for example, the feed amount is 9
Assuming that the feed angle is 0 mm, the feed allocation angle is 180 ° (with respect to the press crank angle), and the feed speed is constant during the feed allocation angle, a feed amount of 90 mm is input to the detector as a necessary operation. The detector uses a feed check synchronization signal (crank angle 3
Calculate "reference feed amount" at 30 ° (90mm * (3
30 ° -270 °) / 180 ° = 30 mm). Sending 27
It starts at 0 ° (see Figure 5 below). At the 330 ° position, the measured feed amount stored in the two latches,
The reference feed amount (30 mm) at 0 ° is compared, and if the difference exceeds a preset allowable range, a feed abnormality detection signal is output and the press is stopped.

Although the above-mentioned disclosed invention is an improvement over the conventional general method, it still has a problem. First, although there is no problem in a feeder such as an NC feeder in which the feed set amount is set by a digital switch, etc., in a general mechanical feeder etc., it is troublesome to separately input the feed set value and the like into the detector. It takes. Alternatively, a device for converting the set numerical value into an electric quantity and a device for transmitting the electric quantity to the detector are required, which is complicated in any case. Second,
In the above specific example, the feed speed was set to a constant speed for simplification, but in reality, the manufacturer of the feed device devised various feed curves so that the press material can be fed at high speed and stably. Is very much. In general, the displacement with respect to the angle can be expressed by a mathematical expression, so if you enter the coefficient of the checkpoint displacement that matches the feed curve, it will be calculated internally and the reference feed amount at the checkpoint will be calculated from the feed set amount value. Can be calculated. For that purpose, it is necessary to input the coefficient at the timing of the checkpoint that matches the feeding curve for each feeding device.

However, when the movement of the feeder itself (for example, the rotation of the roll) is delayed with respect to the crank angle of the press due to the drive system of the feeder and the compliance including backlash in the feeder, compared to the design timing. There are many. That is, it is very difficult to set the reference amount for the checkpoint. In the above example, 90mm
Is sent at a constant speed for a crank angle of 180 °, 0.5 mm is sent per 1 °. If a detection accuracy of 0.1 mm is required, the angle detector and the feed device must be synchronized with a high accuracy of 0.1 to 0.2 °. It can be said that the detection accuracy of the angle detector is not so high, but when the feeding device is synchronized with the angle detector or in the opposite direction, the above-mentioned high precision is close to impossible. Moreover, this is the case of a constant speed, and when a checkpoint is provided near the maximum speed with a non-constant speed feed curve adopted in a normal feeder, the feed amount per angle increases near this point, Higher angle setting accuracy is required, and in order to meet this demand, the setting position of the checkpoint must be limited or the detection accuracy must be lowered. Thus, in the above disclosed invention, there is a practical limitation that the detection accuracy of the feed error is considerably lowered due to the problem of the timing setting accuracy in addition to the detection accuracy of the pickup roll. Further, in the disclosed invention, since the checkpoints are points set in advance, the number is limited to a limited number, and the more checkpoints, the more labor and cost increase.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention solves all of these problems, has a relatively simple structure and is easy to operate, and detects a feed error with high accuracy without increasing the cost. It is an object of the present invention to provide a press material feeding abnormality detecting device capable of performing the above.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention is an apparatus for holding a press material by two rolls for each stroke of a press machine and intermittently supplying the press material with one encoder in association with a material feed roll. , A total of two encoders related to the material to be sent and another encoder are provided, and one encoder detects the number of pulses corresponding to the transfer distance of the material transfer device itself, and the other encoder Is configured to detect the number of pulses corresponding to the movement distance of the material, counts the number of both pulses during transfer, and outputs a feed error signal when the difference exceeds a predetermined value. This is an implementation of a feed error detection device that stops the press.

According to the present invention, as in the above-mentioned published invention,
Since a feed error can be detected without waiting for the feed to finish, a rapid press stop output can be output and the ram can be stopped before the press ram reaches bottom dead center, so that the material is sent normally. It is possible to prevent damage to the die caused by punching when not in use, and to detect a feed error with high accuracy that cannot be achieved in the disclosed invention with a simpler configuration and operation in the disclosed invention. There is.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing the concept of the first embodiment of the present invention, in which a material 5 is intermittently fed by being sandwiched between two feed rolls 3 and 4. The feed roll 3 is the drive side,
The other roll 4 is the driven side which is rotated through the material. According to the present invention, the drive side feed roll 3 is provided with the first encoder 1 in association therewith. A second encoder 2 is provided in association with the driven roll 4. The first encoder 1 detects the rotation angle of the driving roll 3. The second encoder 2 is configured to detect the rotation angle of the driven roll 4. The number of pulses generated by each encoder is equal to the circumferential distance of each roll. For example, two rolls 3,4
When the diameters of the two are equal, both encoders are 3000
When PPR (Pulse Per Revolution) is used and the diameter of the driving roll 3 is φ100 and the diameter of the driven roll 4 is φ50, the driving roll side encoder 1 is 3000 PPR and the driven roll side encoder 2 is 1500 PPR, or 300.
Decelerates to 1/2 at 0PPR.

When the sheet is normally fed with the above configuration, a distance substantially equal to the circumferential distance corresponding to the rotation angle of the drive roll 3,
The material is moved by the frictional force, and the driven roll 4 is rotated by the circumferential distance of the driven roll 4 which is approximately equal to the moving distance of the material.
At this time, encoders 1 and 2 attached to both rolls
Output pulses are equal to or different from each other. The material 5 held between the drive roll 3 and the driven roll 4 is slipped on either side of both rolls and the material is not fed for the set distance, or the external force acts on the material, and the material exceeds the set distance. If a paper is sent, a feed error will occur. At this time, the output pulse of the encoder 1 of the drive roll 3 is constant, but the encoder 2 of the driven roll 4 generates a different number of pulses. The difference between these pulse numbers produces a press stop output according to the circuit example shown in FIG. 3 or 4.

FIG. 2 is a perspective view showing a second embodiment of the present invention, in which both the feed roll 13 and the feed roll 14 may be driven, or only one side (13) may be driven as in the previous example. . In this embodiment, the first encoder 1 is attached to one side of the feed roll and detects its rotation angle. Second
The encoder 2 is attached to the pickup roll 15 in contact with the moving surface of the material 5 so that the moving distance of the material 5 can be detected by the encoder. The number of pulses of the two encoders makes the transfer distance per pulse the same as in the previous embodiment.

During normal feeding, the feed roll 13
The material 5 is moved by the frictional force by a distance approximately equal to the circumferential distance corresponding to the rotation angle of the first roll mounted on the feed roll 13.
Encoder 1 outputs a pulse approximately equal to the moving distance of material 5. On the other hand, the output pulses of the encoder 2 of the pickup roll 15 that outputs the number of pulses corresponding to the moving distance of the material 5 are also equal or the difference is small. Material 5
If the material slips on either side of both rolls or if the material moves due to an external force, the feed error occurs and the feed error occurs. At this time, the output pulse of the first encoder 1 attached to the roll 13 is constant,
The encoder 2 of the pickup roll 15 outputs different pulse numbers. This difference in the number of pulses generates a press stop signal according to the circuit example of FIG. 3 or 4 as in the previous example.

In addition, although not shown, as a third embodiment, even in a feeding device such as a gripper feed which does not depend on the holding of two rolls, a pulse is fed at a distance equal to the feeding pitch in its driving portion. The present invention can be implemented in the same manner as in the second embodiment if the encoder can be mounted for output.

FIG. 3 is a block diagram showing an example of a circuit for carrying out the present invention. A counter 1 is connected to a first encoder 1 and a counter 2 is connected to a second encoder 2. Both counters are connected to a comparator. When the difference between the counter 1 and the counter 2 exceeds a preset value, an abnormal feed is generated from the comparator and the press is stopped. The two counters are reset at the end of the feed after each press stroke. (See Figure 5)

FIG. 4 is a block diagram of a second circuit example.
Both encoder 1 and second encoder 2 are connected to one counter. In this case, subtraction is performed at the same time as addition, and when the counter value exceeds ± predetermined value, a feed error output is output and the press is stopped. As in the case of FIG. 3, the two counters are reset at the completion of feeding at each press stroke.

FIG. 5 is a schematic diagram for explaining the relationship between the press material feed period with respect to the press crank angle and the count effective period. 0 ° is the top dead center of the press ram and 180 ° is the bottom dead center. The count valid period is set to an appropriate angle including the entire press material feeding period. The counter is reset at an appropriate timing immediately before this count valid period.

According to the present invention, various operational effects as described below can be achieved by the simple and low-cost structure described above.
First, since the feed amount is measured by the rotation angle of the drive roll, there is no need to input it into the detector separately, and the operation is simple. Secondly, since the timing of the synchronization signal and the like is also unnecessary, it is not necessary to calculate the reference feed amount with respect to the angle, it is not necessary to consider the curve of the feed speed, and it is possible to widely support a variety of models. . Thirdly, since the rotation of the material driving unit itself in the feeding device is used as a reference, there is no inconvenience even if the movement of the feeding roll is delayed with respect to the crank angle of the press. Fourth, since the drive roll, the material pickup roll, and the two encoders can be configured with a certain degree of rigidity, the two encoders rotate almost equally under normal conditions. According to the apparatus of the present invention, it is possible to set the allowable range with a value close to the resolution of the encoder, and it is possible to perform detection with extremely high accuracy. Fifthly, when the difference between the two counters exceeds the allowable range (Circuit example 1), or when the value of the counter to be added / subtracted exceeds the allowable range (Circuit example 2), an abnormal output can be output instantaneously. Out. That is, it is possible to check the entire range of the feed angle. Lastly, two encoders are required, but instead an angle detector, calculation of a reference amount for a checkpoint, etc. are not required, so the cost can be reduced compared to the conventional example, and the practical effect is great.

[Brief description of drawings]

FIG. 1 is a schematic perspective view conceptually showing a first embodiment of the press material feeding abnormality detecting device according to the present invention.

FIG. 2 is a schematic perspective view showing a second embodiment of the present invention.

FIG. 3 is a block diagram showing an example of a circuit for implementing the present invention.

FIG. 4 is a block diagram showing a second example of the same circuit.

FIG. 5 is a schematic diagram illustrating a relationship between a press material feeding period for a press crank and a count valid period.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st encoder 2 ... 2nd encoder 3,13 ... Drive side feed roll 4 ... Follower side roll 5 ... Press material 15 ... Pickup roll

Claims (3)

[Claims] 1. A device for intermittently supplying a press material by holding two rolls for each stroke of the press machine,
A total of two encoders are provided, one related to the material feeding roll and the other related to the material to be fed.
One encoder detects the number of pulses corresponding to the moving distance of the material transfer device itself, and the other encoder detects the number of pulses corresponding to the moving distance of the material, and both pulse numbers are being transferred. The feed abnormality detecting device is configured to output the feed abnormality signal when the difference is equal to or more than a predetermined value. 2. The one encoder is attached to a rotary shaft of a drive side roll (3) of the two feed rolls,
The abnormality detection device according to claim 1, wherein the other encoder is attached to a rotation shaft of the driven roll (4). 3. The one encoder is attached to a rotary shaft of a drive side roll (3) of the two feed rolls,
The abnormality detection device according to claim 1, wherein the other encoder is attached to a rotary shaft of the pickup roll (15) which comes into contact with the moving surface of the material (5).