JP3603084B2 - Blanking system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention, workpieces even when part of the optical axis of the light sensor is passing light and shielded by reason of an equal is the long object, position 置Gatokoro constant of vent light and the light blocking optical axis The present invention relates to a safety system such as a press machine having a function of outputting a machine operation permission signal.
[0002]
[Prior art]
In a safety measure for a press machine or the like, a transmissive light beam type sensor is often provided so that an operator does not accidentally enter a danger limit (operation range of a slide or a mold) of the machine. However, in an operation for processing a long object such as an aluminum sash, it is impossible to use the device because the long object shields a part of the optical axis of the light beam type sensor.
[0003]
For this reason, conventionally, a method has been adopted in which the safety of the worker is ensured by using a light beam type sensor of a plurality of optical axis shielding type. As one example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 2-271199 (Japanese Patent No. 2712043).
[0004]
This patent claims from the claims that "means for scanning all optical axes for a plurality of optical axes to detect the presence or absence of blocked optical axes, Light-shielding axis storage means for storing an optical axis, and means for outputting an optical-axis cutoff signal when a cutoff of an optical axis other than the optical axis stored in the light-shielding axis storage means is detected in the scan in the execution mode. A multi-optical-axis light-shielding mode that outputs an optical-axis cutoff signal only when an optical axis other than those previously stored in the light-shielding axis storage means is interrupted, and when all the optical axes are interrupted. A setting switch for outputting a mode setting signal for setting any one of the normal cutoff modes for outputting the optical axis cutoff signal, and the first after the multi-optical axis light shielding mode is set by the mode setting signal. Scan as described above Is a ray safety device configured machine tools to process as the scan mode.
[0005]
[Problems to be solved by the invention]
By the way, in the publication described above, in the setting mode, all the optical axes are scanned and all the optical axes in which the interruption is detected are stored in the light shielding axis storage means, and in the execution mode, the light shielding axes are previously stored. Since the optical axis cutoff signal is output only when the optical axis other than the one stored in the storage means is interrupted, it is smaller than the workpiece stored in the light shielding axis storage means (the height is lower). ) If the workpiece is inserted by mistake, the optical axis cutoff signal will not be output, so that there is a problem that different workpieces are processed differently.
[0006]
Further, even in a state in which the worker places his / her hand on the low workpiece, the processing machine operates if the workpiece is lower than the height of the workpiece stored in the light-shielding axis storage means. Since the example is a one-dimensional one in which the light-emitting device and the light-receiving device are installed in the left-right direction (up-down direction), the height direction (width direction) of the workpiece matches the one stored in the light-shielding axis storage means. However, even if there is an operator's hand on the side (upper side) of the workpiece, the light-shielding axis storage means does not output the optical axis cutoff signal, so that the processing machine operates and there is a problem in terms of safety for the operator. Could have occurred.
[0007]
Also, elements that are not fail-safe for storage and comparison of the light shielding axis storage means, for example, an optical axis data storage unit, a blocking optical axis number storage unit, a blocking optical axis number comparison unit, a data comparison unit, a mode determination unit, a synchronization signal generation unit Since a selection signal generator, multiplexer, demultiplexer, decoder, etc. are used, if any one of these elements fails or malfunctions, the stopped machine suddenly starts up or There is a danger of a catastrophic disaster due to the machine not being stopped, and a catastrophic product defect such as misalignment of the product, mixing of different products, and mis-teach of the product.
[0008]
An object of the present invention is to solve the above-described problems, and an object of the present invention is to prevent the occurrence of a human obstacle or a product defect due to the insertion of a different workpiece, and to prevent a hardware failure or a software bug. In this case, the operation permission signal is not output in the case where the error occurs, so that a blanking system in which the processing machine operates on the safer side is provided.
[0009]
[Means for Solving the Problems]
The blanking system of the present invention achieves the above-mentioned object, and its means is that a plurality of light emitters and light receivers intersect at an insertion port of a workpiece in a processing device such as a press machine so that two pairs face each other. A light-type sensor installed at the same time, a changeover switch for switching between a teaching mode and an operation mode, an operating device for giving a teaching command and an operation command, and a switch for switching the changeover switch to the teaching mode and giving a teaching command by the operating device. And a storage device for storing an optical axis pattern light-shielded and transmitted by a workpiece inserted between the light beam sensors, and a driving command given by the operating device, between the light beam sensors. Comparing the light-shielding and light-transmitting state of the optical axis by the workpiece inserted into the light-shielding and light-transmitting state stored in the storage means. And a determination device that outputs an operation permission signal when an output indicating that the light-shielding and light-transmitting states of the optical axis from the comparison device match is executed, and executes the functions of the storage device, the comparison device, and the determination device. Programmable controller having different kinds of redundant hardware and software for performing the operation, a self-diagnosis device for periodically confirming the identity of all memories at the time of system startup and operation, and an operation of the programmable controller A fail-safe AND operation element that outputs an operation permission signal only when all the results are the same, and a light-shielding and light- transmitting optical axis obtained by a workpiece inserted during actual processing. pattern, consistent with the optical axis pattern stored in the storage device by the teachings and Starring of the programmable controller Results, characterized in that the operation permission signal is outputted from the AND operation element only when all the same.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a blanking system according to the present invention will be described with reference to the drawings. In the present invention, "blanking" is a term meaning invalidation in English. Hereinafter, the disabled optical axis is referred to as a “blanking optical axis”. A system in which only a predetermined optical axis position of the beam safety device is invalidated is referred to as a “fixed blanking system”, and a system in which only a predetermined number of optical axes of the beam safety device is invalidated is referred to as a “variable blanking system”. Ranking system ".
[0013]
FIG. 1 is a configuration diagram of a fixed blanking system according to the present invention.
This system comprises a light beam sensor 1 in which a plurality of light emitters and light receivers are installed facing each other in a vertical direction or a horizontal direction, a switch 2 for specifying whether each optical axis position of the sensor is valid or invalid, and a switch invalidating the switches. And a control circuit 3 for outputting a machine operation permission signal when all the optical axis positions designated as effective are light-shielded and all the optical axis positions designated as valid are light-transmitting.
[0014]
Therefore, a valid / invalid switch is set for each optical axis so that only the optical axis that is blocked when the long object 4 is properly entering is invalidated, and all other optical axes are valid. Then, the output of the machine operation permission signal can be stopped when a finger or the like accidentally enters instead of a long object (entry path A of the finger or the like in FIG. 1) or when a different type is fed.
[0015]
In the case of the embodiment of the variable blanking system, the switch 2 in FIG. 1 in the above embodiment is not a switch for designating the number of invalid optical axes of the light beam type sensor 1, and the number of light-shielded optical axes Is provided with a control circuit 3 for outputting an operation permission signal when the number specified by the switch is provided.
[0016]
Therefore, if the number of optical axes to be shielded when the long object 4 is properly entered is set in the switch, when a finger or the like enters by mistake instead of the long object (the finger or the like in FIG. 1). When a different type is fed or the number of optical axes to be blocked is different, the output of the machine operation permission signal can be stopped.
[0017]
Next, a two-dimensional blanking system according to a second embodiment will be described. The light sensor 1 shown in FIG. 1 is installed so as to face the vertical direction and the horizontal direction. In this case, even if the human body enters the danger limit from either the vertical or horizontal direction of the long object. (This corresponds to the approach paths C and D of the fingers and the like in FIG. 2), and has a feature that the machine can be stopped.
[0018]
In the blanking systems according to the first and second embodiments, it is necessary to previously set the position and number of the blanking optical axes by operating a key switch, a dip switch, and the like. . However, for long products such as aluminum sashes, in which the number of products in one lot is extremely small and the number of varieties is enormous (the number of varieties may reach tens of thousands), dip switches etc. To specify the blanking optical axis by operating is a very complicated operation for the operator.
[0019]
Therefore, in the present invention, when the type of long object is changed, the blanking optical axis for each type can be taught simply by operating the footbedal or the like. When configuring such a system, it is convenient to teach the blanking optical axis using a programmable controller (hereinafter abbreviated as "PLC"). However, the conventional PLC has a problem that an erroneous operation permission signal is generated when a failure occurs because control of the storage device is not fail-safe. Further, there is a problem that an erroneous operation permission signal is generated even when a failure occurs in hardware other than the storage device or when a bug is included in the control program (software).
[0020]
Therefore, in the present invention, PLCs having different types of software and hardware are multiplexed (heterogeneous redundancy), and when all the operation results of these multiplexed PLCs match, a machine operation permission signal is output. The problem was to solve this problem by developing a system that does this. Hereinafter, this embodiment will be described with reference to FIG.
[0021]
This system includes a changeover switch 7 for switching between a teaching mode and an operation mode, an operation device 8 for giving a teaching command and an operation command, and a light blocking state of each optical axis when the teaching command is generated (in the case of a fixed blanking system, light is blocked). Storage device 9 for storing the position of the optical axis, the number of optical axes that are blocked in the variable blanking system, and the light-shielded state of each optical axis when the operation command is issued and each light stored in the storage device. A comparison device 10 that compares the light-shielded state of the axes and a determination device 11 that outputs an operation permission signal when the light-shielded state of each optical axis when a teaching command is generated and when an operation command is generated match. The operating device 8 may use not only buttons operated by hand but also a foot switch operated by foot.
[0022]
Hereinafter, an operation procedure of the present apparatus when processing a long object with a stepping-type press machine will be described with reference to the drawings. In this device, the operator first switches the changeover switch 7 to the teaching mode, then sets the mold in the proper position while holding the long object with both hands, and operates the foot switch 8 (teaching instruction). , The blanking optical axis is stored in the storage device 9. In the case of the fixed blanking system, it is necessary to specify the position of the light-shielded optical axis, and in the case of the variable blanking system, it is necessary to specify the number of light-shielded optical axes. Then, a changeover switch 12 for switching between fixed blanking and variable blanking is separately required. Since the switching frequency of this switch is usually extremely low, it is preferably provided on a circuit board or the like that cannot be easily operated by an operator.
[0023]
Next, after the changeover switch 7 is switched to the operation mode, the slide is started by operating the foot switch 8 (driving command) while holding the long object with both hands. When the movement is in progress, since the optical axes other than the blanking optical axis are shielded, the slide does not start. Also, when the position of the long object is displaced, or when a long object of a different type is inserted by mistake, the optical axes other than the blanking optical axis are blocked or the blanking optical axis becomes transparent. The slide does not start in this case.
[0024]
In this example, the operating device 8 for giving the teaching command and the driving command is shared, but these may be different. In particular, when teaching is possible without holding a long object with both hands, unless the device for giving a teaching command is operated by both hands, the shape of the operator's finger may be stored as the shape of the long object. Therefore, special attention should be paid to this point for safety.
[0025]
Because of the above configuration, even if there are many types of long objects, a simple teaching system that does not require operating key switches, dip switches, etc. every time the type is changed Is possible.
[0026]
By the way, as a fail-safe measure in the event of a hardware failure or a software bug, a method of multiplexing the same type of CPU has conventionally been adopted. Since the hardware and software processing methods are the same, there is a drawback that the probability of simultaneous multiple failures is extremely high as compared with the heterogeneous redundancy method. Therefore, in a system in which the occurrence of a failure may immediately lead to a serious disaster, such as a work by a press machine, multiplexing of hardware and software must be based on a diversity structure.
[0027]
Next, an embodiment of the fail-safe blanking system having the diversity structure will be described with reference to FIG.
This system is composed of three types of PLCs 13 to 15 which have different types of redundancy (hereinafter, referred to as “diversity structure”), a fail-safe logical product operation element 16 and a self-diagnosis device 17. And a control circuit 18 for turning on an operation permission signal, which is a signal output of the AND operation element 16, only when all of the operation results 13 to 15 are the same.
[0028]
Since these three types of PLCs have different hardware structures, it is extremely unlikely that the three types of PLCs will cause a hardware failure at the same time. Further, since the software processed on each CPU is also different, the possibility that an operation permission signal is erroneously output due to a software bug (error) is extremely low.
[0029]
Further, in a system using a PLC, a malfunction due to an abnormality in a memory causes a problem. However, in this system, a memory is multiplexed for each CPU and a self-diagnosis device is used to periodically start and operate the system. It confirms the identity of all memories. Further, since the AND operation element used in this system is a fail-safe element, it does not output an ON signal by mistake when a failure occurs.
[0030]
As described above, in the blanking system according to the present embodiment, the failure that does not erroneously output the operation permission signal even in the case of abnormality or failure of the PLC hardware, software, memory, or the like, and failure of the AND operation element. A safe blanking system can be realized.
[0031]
In the above-described embodiment, as a fail-safe two-dimensional blanking system provided with deterministic disaster prevention means, a plurality of light beam sensors are provided in different directions, and a human body is placed at any place in a predetermined two-dimensional area. Even if an object or an object enters, a human body or an object can be detected.
[0032]
Further, a fail-safe blanking system provided with deterministic product inspection means is used not only when a misalignment of a product, mixing of a different product, a mistake in teaching a product, or any other abnormal state occurs, but also in the memory. Even when a failure or abnormality occurs in any of the device, the comparison device, and the determination device, the operation permission signal of the machine can be reliably stopped to prevent erroneous processing of the product.
[0033]
Further, a fail-safe two-dimensional blanking system with deterministic product inspection means is provided with a plurality of light-beam sensors in different directions so that the product can enter any part of a predetermined two-dimensional area. Misalignment, mixing of different products, incorrect teaching of products, and other abnormal conditions can be detected.
[0034]
Further, in the above-described embodiment, the PLC is used to constitute the diversity structure. However, hardware other than PLC may be used for different types of redundancy. Or, the case where they are installed facing each other in the "horizontal direction" has been described.
[0035]
Apparatuses to which the present invention can be applied can be applied to almost all apparatuses capable of entering a long object within the movable range of the machine. For example, it can be applied to press machines for processing long objects, press brakes for processing large-sized plates, printing presses, roll machines, etc. Also, in production systems, there are openings for loading and unloading products. In many cases, a unit is provided, but in such a case, the present invention can also be applied as a device for distinguishing between a human body and an object.
[0036]
【The invention's effect】
As described above, the present invention provides an operation permission signal only when a workpiece having a predetermined shape is inserted into a space of a light beam type sensor installed in such a manner that a plurality of light emitters and a plurality of light receivers cross each other and are opposed to each other. In the blanking system that is configured to output, the optical axis pattern light-shielded and transmitted by the workpiece inserted between the light emitter and the light receiver is stored in the light receiver in advance, and is inserted at the time of actual processing. further comprising a control circuit for the optical axis pattern of light shielding and passing light photodetector-side for receiving light from the projector by the workpiece, and outputs the operation permission signal only when they match with the optical axis patterns stored in advance Thereby, it is possible to process a long object without harming the fingers of the worker, and further enhance the safety by using the light beam type sensor as a two-way light emitter and a light receiver. It can be.
[0037]
In addition, a storage device that stores the light-shielding and light-transmitting state of each optical axis when a teaching command is generated, and a light-shielding and light-transmitting state of each optical axis that is stored when the operation command is generated. Since there is a comparison device that compares the light transmission state, even if there are many types of long objects, the blanking light can be easily performed without complicated operation every time the type is changed. Can teach the axis.
[0038]
In addition, since a programmable controller with heterogeneous redundancy and a fail-safe logical AND element are provided, a fail-safe system that does not erroneously output an operation permission signal in the event of a fault can be configured to prevent hardware failure. When a software bug occurs, the machine does not output the operation permission signal, so the processing machine operates more safely, so the stopped machine suddenly starts up or the running machine stops. This has the effect of preventing a fatal disaster due to disappearance and preventing a fatal product defect such as misalignment of the product, mixing of different products, and a mistake in teaching the product.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a blanking system showing an embodiment according to the present invention.
FIG. 2 is a configuration diagram of a blanking system showing another embodiment.
FIG. 3 is a configuration diagram of a blanking system showing still another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Beam sensor 2 Switch 3 Control circuit 4 Long object 5 Beam sensor (left-right direction)
6. Light beam sensor (vertical direction)
Reference Signs List 7 Changeover switch 8 Operating device 9 Storage device 10 Comparison device 11 Judgment device 12 Changeover switches 13 to 15 Programmable controller 16 with heterogeneous redundancy 16 Fail-safe AND operation element 17 Self-diagnosis device 18 Control circuit 19 Long object

Claims (1)

A light beam sensor in which a plurality of light emitters and light receivers intersect with each other at an insertion port of a workpiece in a processing device such as a press machine and are installed to face each other;
A changeover switch for switching between the teaching mode and the operation mode,
An operation device for giving a teaching command and a driving command;
A storage device for switching the changeover switch to a teaching mode, and storing an optical axis pattern that is shielded and transmitted by a workpiece inserted between the light beam type sensors when a teaching command is given by the operating device; ,
In a state where an operation command is given by the operating device, a light-shielding and light-transmitting state of an optical axis by a workpiece inserted between the light-ray sensors and a light-shielding and light-transmitting state stored in the storage unit A comparison device for performing a comparison,
A determination device that outputs an operation permission signal when an output indicating that the light-shielding and light-transmitting states of the optical axis from the comparison device match is input,
A programmable controller having heterogeneous redundant hardware and software for performing the functions of the storage device, the comparison device and the determination device;
A self-diagnosis device that periodically checks the identity of all memories at system startup and operation,
A fail-safe AND operation element that outputs an operation permission signal only when the operation results of the programmable controller are all the same,
The optical axis pattern of light shielding and light transmission of the optical axis obtained by a workpiece inserted at the time of actual processing matches the optical axis pattern stored in the storage device by teaching , and the programmable A blanking system wherein an operation permission signal is output from an AND operation element only when all operation results of the controller are the same .

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