JP2020121328A - Safety device for press brake, press brake, and safety monitoring method - Google Patents

Abstract

To secure the safety of bending work at a high level while suppressing complication of the bending work.SOLUTION: A safety device 34 for a press brake is provided with a plurality of distance sensors 36 for detecting a top face of a work-piece W or a top face of a lower mold 14, and the plurality of distance sensors 36 are provided at upper positions of the lower mold 14 along a width direction. The safety device 34 for a press brake is provided with an entry determination part for determining whether a foreign matter E enters between an upper mold 12 and the lower mold 14 on the basis of detection values of the plurality of distance sensors 36 during downward movement of an upper table 24.SELECTED DRAWING: Figure 2

Description

The present invention relates to a press brake safety device, a press brake, and a safety monitoring method for monitoring the entry of foreign matter between an upper mold and a lower mold.

In recent years, in order to sufficiently secure the safety of bending work, the press brake is often equipped with an optical press brake safety device (see Patent Document 1). The optical press brake safety device is provided on one side of the upper table, and is equipped with a projector that projects monitoring light such as laser light along the width direction (width direction of the press brake) passing directly under the upper mold. , A light receiver provided on the other side of the upper table and receiving the monitoring light. The optical press brake safety device is equipped with a monitoring controller for monitoring the entry of foreign matter between the upper mold and the lower mold, and the projector and the light receiver are connected to the monitoring controller. ing. The monitoring controller determines whether or not a foreign matter has entered between the upper mold and the lower mold based on the light receiving state (light receiving result) of the light receiver during the lowering operation of the upper table. Then, when it is determined that a foreign matter has entered between the upper mold and the lower mold, the control device of the press brake controls the lifting actuator to stop the lowering operation of the upper table.

JP, 2007-203310, A

By the way, since the monitoring light is projected right below the upper mold along the width direction, the upper mold does not approach the lower mold even if foreign matter is present on or near the lower mold. As long as the monitoring controller cannot determine that a foreign object has entered between the upper mold and the lower mold. Therefore, in the optical press brake safety device, there is a problem that it is not easy to secure a high level of safety in bending work.

Further, for the same reason, when the shadow of the upper mold is enlarged due to the influence of the diffraction of the monitoring light due to the temperature difference around the upper mold, there is no foreign substance between the mold and the lower mold, The monitoring controller may erroneously determine that a foreign object has entered between the upper mold and the lower mold. Therefore, there is a problem that the lowering operation of the upper table is unnecessarily stopped and the bending work becomes complicated.

Therefore, in order to solve the above-mentioned problem, the present invention can monitor the entry of foreign matter between the upper mold and the lower mold without using the monitoring light projected along the width direction. An object is to provide a safety device for a brake, a press brake, and a safety monitoring method.

The safety device for a press brake according to the first embodiment of the present invention is provided above the lower die in the press brake along the width direction, and detects the distance to the upper surface of the work or the upper surface of the lower die. Whether a foreign object has entered between the upper mold and the lower mold based on the detection values of the plurality of distance sensors during the lowering operation of the plurality of distance sensors and the upper table relative to the lower table. An entry determination unit for determining whether or not it is provided.

According to the first embodiment of the present invention, during the relative lowering operation of the upper table with respect to the lower table, the entry determination unit determines the upper die and the upper die based on the detection values of the plurality of distance sensors. It is determined whether or not a foreign matter has entered between the lower die. Thereby, based on the detection values of the plurality of the distance sensors, without using the monitoring light projected along the width direction of the press brake, the foreign matter between the upper mold and the lower mold is detected. The approach can be monitored. Therefore, without considering the expansion of the shadow of the upper mold, if there is a foreign substance on or near the lower mold, the upper mold does not approach the lower mold. However, it can be determined that a foreign matter has entered between the upper mold and the lower mold.

In the first embodiment of the present invention, the entry determination unit determines whether one of the detection values of the plurality of distance sensors corresponds to the detection value corresponding to the distance to the upper surface of the work and the upper surface of the lower mold. By determining whether or not the detection value is equivalent to the distance to the foreign matter other than the detection value corresponding to the distance, it is determined whether or not the foreign matter has entered between the upper mold and the lower mold. Good. In this case, when the entry determination unit determines that one of the detection values of the plurality of distance sensors is a detection value corresponding to the distance to the foreign object, the entry determination unit calculates the size of the foreign object, It may be determined whether or not a foreign object has entered between the upper die and the lower die by determining whether or not the size exceeds the allowable range.

The safety device for a press brake according to the first embodiment of the present invention performs a relative lowering operation of the upper table when it is determined that a foreign matter has entered between the upper mold and the lower mold. A stop signal output unit that outputs a stop signal for stopping may be provided.

In the safety device for a press brake according to the first embodiment of the present invention, before the relative lowering operation of the upper table is started, the detection values of the plurality of distance sensors are classified into a plurality of types according to the size. The value classification unit and the detection values of the plurality of distance sensors are classified into two types: a group of detection values corresponding to the distance to the upper surface of the work and a group of detection values corresponding to the distance to the upper surface of the lower mold. When it is determined that the work on the lower die is appropriate, the appropriate determination unit may be provided. Further, the press brake safety device according to the first embodiment of the present invention allows the relative lowering operation of the upper table when the work on the lower die is determined to be appropriate. A permission signal output unit that outputs a permission signal may be provided.

In the first embodiment of the present invention, the detection value classification unit corresponds the detection values of the plurality of distance sensors to a group of detection values corresponding to the distance to the upper surface of the work and the distance to the upper surface of the lower mold. When the detection values cannot be classified into two groups, the detection values of the plurality of distance sensors corresponding to the width dimension of the work are regarded as a group of detection values corresponding to the distance to the upper surface of the work, and the other distances The detection values of the sensor may be regarded as a group of detection values corresponding to the distance to the upper surface of the lower mold. In this case, in the safety device for a press brake according to the first embodiment of the present invention, is the variation in the group of the detection values of the plurality of distance sensors corresponding to the width dimension of the work within the allowable range as the warp of the work? A warp determination unit that determines whether or not it may be provided.

In the first embodiment of the present invention, the detection value classification unit corresponds the detection values of the plurality of distance sensors to a group of detection values corresponding to the distance to the upper surface of the work and the distance to the upper surface of the lower mold. If it cannot be classified into two types of detection value groups, it corresponds to the width dimension of the work excluding the detection value of the distance sensor corresponding to the end side of the work, provided that the bending is box bending. The detection values of the plurality of distance sensors are regarded as a group of detection values corresponding to the distance to the upper surface of the work, and the detection values other than the detection values of the plurality of distance sensors corresponding to the width dimension of the work are set in the lower mold. It may be regarded as a group of detected values corresponding to the distance to the upper surface.

In the first embodiment of the present invention, the detection value classification unit corresponds to a group of detection values corresponding to the distances to the upper surface of the work and the distances to the upper surface of the lower mold from the detection values of the plurality of distance sensors. When the detection values cannot be classified into two types, the maximum detection value among the detection values of the plurality of distance sensors is regarded as a detection value group corresponding to the distance to the upper surface of the lower mold, and the maximum value is detected. The detected value close to the value obtained by subtracting the thickness of the workpiece from the detected value is regarded as a group of detected values corresponding to the distance to the upper surface of the workpiece, and the remaining detected values are regarded as a group of detected values corresponding to the distance to the foreign matter. You may regard it. In this case, in the safety device for a press brake according to the first embodiment of the present invention, the entry determination unit calculates the size of the foreign matter before the relative lowering operation of the upper table is started, and the calculated foreign matter is calculated. It may be determined whether or not a foreign object has entered between the upper mold and the lower mold by determining whether or not the size exceeds the allowable range.

The press brake according to the second embodiment of the present invention includes the safety device for a press brake according to the first embodiment of the present invention.

A safety monitoring method according to a third embodiment of the present invention is provided with a plurality of units provided along a width direction above a lower die in a press brake and detecting a distance to an upper surface of a work or an upper surface of the lower die. Whether a foreign object has entered between the upper die and the lower die based on the detection values of the plurality of distance sensors during the lowering operation of the upper table relative to the lower table using To determine.

According to the third embodiment of the present invention, the upper die and the lower die are based on the detection values of the plurality of distance sensors without using the monitoring light projected along the width direction of the press brake. The entry of foreign matter between the molds can be monitored. Therefore, without considering the expansion of the shadow of the upper mold, if there is a foreign substance on or near the lower mold, the upper mold does not approach the lower mold. However, it can be determined that a foreign matter has entered between the upper mold and the lower mold.

ADVANTAGE OF THE INVENTION According to this invention, the safety|security of bending work can be ensured in a high level, suppressing complexity of bending work.

FIG. 1 is a schematic front view of a press brake according to an embodiment of the present invention. FIG. 2 is a control block diagram of the press brake according to the embodiment of the present invention. FIG. 3 is a schematic diagram showing a detection state of the plurality of distance sensors before the lowering operation of the upper table is started. FIG. 4A is a schematic view showing a state of detection by the plurality of distance sensors in a normal state before the lowering operation of the upper table is started. FIG. 4B is a diagram showing the relationship between the sensor positions and the detection values of the plurality of distance sensors before the lowering operation of the upper table starts in that state. FIG. 5A is a schematic diagram showing a state of detection by a plurality of distance sensors in a state where a work having a warp is supported by the lower die before the lowering operation of the upper table starts. FIG. 5B is a diagram showing the relationship between the sensor positions and the detection values of the plurality of distance sensors before the lowering operation of the upper table is started in that state. FIG. 6A is a schematic diagram showing a state of detection by a plurality of distance sensors in a state where foreign matter has entered between the upper die and the lower die during the lowering operation of the upper table or before the lowering operation is started. is there. FIG. 6B is a diagram showing the relationship between the sensor positions and the detection values of the plurality of distance sensors in that state. FIG. 7A is a schematic diagram showing a state of detection by a plurality of distance sensors in a state where a workpiece having a flange is supported on the lower die before the lowering operation of the upper table is started. FIG. 7B is a diagram showing the relationship between the sensor positions and the detection values of the plurality of distance sensors before the lowering operation of the upper table in that state is started. FIG. 8A is a flowchart showing the operation of the press brake according to the embodiment of the present invention. FIG. 8B is a flowchart showing the operation of the press brake according to the embodiment of the present invention. FIG. 8C is a flowchart showing the operation of the press brake according to the embodiment of the present invention.

Embodiments of the present invention will be described with reference to FIGS. 1 to 8C.

In the specification and claims of the present application, “provided” is intended to include not only being directly provided but also indirectly being provided through another member. The “foreign matter” refers to an object other than the work, such as a worker's finger and a tool. The “width direction” means the width direction of the press brake, and in the embodiment of the present invention, the left-right direction. The “depth direction” means the depth direction of the press brake, and in the embodiment of the present invention, the front-back direction. The “vertical distance” is intended to include not only the distance in the vertical direction but also the distance in the direction slightly inclined in the vertical direction.

In the drawings, "FF" indicates forward, "FR" indicates backward, "L" indicates left, "R" indicates right, "U" indicates upward, and "D" indicates downward. The alternate long and short dash line in FIGS. 3, 4(a), 5(a), 6(a), and 7(a) indicates ultrasonic waves. The sensor positions "c", "d", "e", "f", "g", and "h" in FIGS. 4B, 5B, 6B, and 7B are shown. , “I”, and “j” indicate the alphabetical code of the corresponding distance sensor.

As shown in FIG. 1, a press brake 10 according to an embodiment of the present invention is a processing machine that bends a plate-shaped work (sheet metal) W by cooperation of an upper die 12 and a lower die 14. is there. Further, the press brake 10 includes a main body frame 16, and the main body frame 16 has a pair of side plates 18 facing each other in the width direction (left-right direction) and a plurality of connecting members (which connect the pair of side plates 18). (Not shown).

A lower table 20 extending in the width direction is provided at the bottom of the body frame 16. A lower die holder 22 that detachably holds the lower die 14 is provided above the lower table 20. An upper table 24 extending in the width direction is provided on the upper part of the main body frame 16 so as to be able to move up and down (movable in the vertical direction). The upper table 24 is attached to the lower mold holder 22 (lower table 20). Facing up and down. A plurality of upper mold holders 26 that detachably hold the upper mold 12 are provided below the upper table 24. At the upper part of each side plate 18, a hydraulic lifting cylinder 28 is provided as a lifting actuator for lifting the upper table 24. Further, a back gauge 30 (see FIG. 2) for positioning the work W in the depth direction (front-rear direction) with respect to the lower mold 14 is provided on the back side (rear side) of the lower table 20.

Note that the lower table 20 may be configured to be movable up and down instead of being configured to be movable up and down. In other words, it suffices if the upper table 24 can be moved up and down relatively to the lower table 20. Instead of using the hydraulic lifting cylinder 28 as the lifting actuator, a lifting servomotor (not shown) may be used.

As shown in FIG. 2, the press brake 10 includes a control device (NC device) 32 that controls the pair of lifting cylinders 28, the back gauge 30, and the like based on a processing program. The control device 32 is configured by a computer. The control device 32 includes a memory (not shown) that stores a machining program, mold information, work information, product information, and the like, and a CPU (not shown) that executes the machining program. Omitted) and. The mold information includes information indicating the shape of the upper mold 12, the size and the arrangement position of each part, and the shape of the lower mold 14, the size of each part, the position and the like. The work information includes information indicating the material, shape, and thickness of the work W, dimensions of each part, and the like. The product information includes information indicating the shape of the product (not shown) and the dimensions of each part. When the bending is box bending, the product information includes information indicating the height dimension of the flange. The machining program includes information indicating the distance between the upper table 24 and the upper surface of the lower die 14 before the lowering operation of the upper table 24, and the upper table 24 and the upper surface of the work W before the lowering operation of the upper table 24 are started. It includes information indicating the distance of.

The press brake 10 includes a press brake safety device 34 that monitors the entry of foreign matter other than the work W between the upper mold 12 and the lower mold 14. The specific configuration of the press brake safety device 34 is as follows.

As shown in FIGS. 1 and 2, on the lower end side of the upper table 24, a plurality of ultrasonic distance sensors 36 for detecting the distance in the vertical direction to the upper surface of the work W or the upper surface of the lower mold 14 are provided. It is provided along the width direction (left-right direction). Each distance sensor 36 faces the lower mold 14 or the lower mold holder 22 in the vertical direction. The height positions of the plurality of distance sensors 36 with respect to the upper table 24 are located at the same height position.

Instead of providing the plurality of distance sensors 36 on the lower end side of the upper table 24 as the upper position of the lower mold 14, the distance sensors 36 are provided on the front side of the upper mold 24 in the upper mold 12, the upper mold holder 26, or the body frame 16. It may be provided on a fixed support member (not shown). The distance sensor 36 may not face the lower mold 14 or the lower mold holder 22 in the vertical direction. The press brake safety device 34 may use a laser distance sensor (not shown) or an eddy current distance sensor (not shown) instead of the ultrasonic distance sensor 36.

The press brake 10 includes a monitoring controller 38 for monitoring the entry of foreign matter other than the work W between the upper mold 12 and the lower mold 14. The monitoring controller 38 is configured by a computer, and the monitoring controller 38 is connected with a plurality of distance sensors 36, a control device 32, and the like. The monitoring controller 38 has a memory (not shown) that stores a monitoring program, sensor information, and the like, and a CPU (not shown) that executes the monitoring program. The sensor information includes information indicating the position of each distance sensor 36 in the width direction (horizontal direction) and the like.

The CPU of the monitoring controller 38 invalidates the detection of the distance sensors 36 other than the plurality of distance sensors 36 corresponding to the lower mold 14 among all the distance sensors 36. Specifically, for example, in the case shown in FIG. 3, the CPU of the monitoring controller 38 includes a plurality of distance sensors 36c to 36l which correspond to the lower mold 14 (opposite vertically). The detection of the distance sensors 36a, 36b, 36k, 36l other than 36j is invalidated.

As shown in FIG. 2, the monitoring program executed by the CPU of the monitoring controller 38 has a function as a detection value classification unit 40, a function as an appropriateness determination unit 42, a function as a permission signal output unit 44, and an entry determination unit 46. , A function as the stop signal output unit 48, and a function as the warp determination unit 50. Then, the specific contents of the detection value classification unit 40, the appropriateness determination unit 42, the permission signal output unit 44, the entry determination unit 46, the stop signal output unit 48, and the warp determination unit 50 are as follows.

The detection value classification unit 40 classifies the detection values of the plurality of distance sensors 36 into a plurality of types according to the size by using, for example, cluster analysis. For example, in the case shown in FIGS. 4A and 4B, the detection value classification unit 40 sets the detection values of the plurality of distance sensors 36c to 36j to the detection value (dv1) corresponding to the distance to the upper surface of the work W. And a group of detection values (dv2) corresponding to the distance to the upper surface of the lower mold 14 are classified. The group of detection values of the plurality of distance sensors 36e to 31h becomes the former group, and the group of detection values of the plurality of distance sensors 36a, 36b, 36i, 36j becomes the latter group.

The detection value classifying unit 40 has two types of detection values of the plurality of distance sensors 36: a group of detection values corresponding to the distance to the upper surface of the work W and a group of detection values corresponding to the distance to the upper surface of the lower mold 14. When it is not possible to classify into, the detection values of the plurality of distance sensors 36 corresponding to the width dimension of the work W are regarded as a group of detection values corresponding to the distance to the upper surface of the work W. The detection value classification unit 40 regards the detection values of the other distance sensors 36 as a group of detection values corresponding to the distance to the upper surface of the lower mold 14. For example, in the case shown in FIGS. 5A and 5B, the detection value classification unit 40 divides the group of detection values of the plurality of distance sensors 36d to 31i into the group of detection values corresponding to the distance to the upper surface of the work W. And the group of detection values of the plurality of distance sensors 36c and 36j is regarded as a group of detection values corresponding to the distance to the upper surface of the lower mold 14.

The appropriateness determining unit 42 is divided into two groups, that is, a group of detection values corresponding to the distance to the upper surface of the work W and a group of detection values corresponding to the distance to the upper surface of the lower mold 14. When the work W on the lower die 14 is classified, it is determined whether or not the work W on the lower die 14 is classified. Specifically, the adequacy determination unit 42 determines that the work W on the lower mold 14 is appropriate when the predetermined first requirement to the predetermined third requirement are satisfied. The adequacy determining unit 42 determines that the work W on the lower mold 14 is not appropriate when one of the predetermined first requirement to the third requirement is not satisfied.

Here, the predetermined first requirement is that the detection value d corresponding to the distance to the upper surface of the work W is equal to or substantially equal to the distance between the upper table 24 and the upper surface of the work W before the lowering operation of the upper table 24 is started. It is in agreement. The predetermined second requirement is that the detection value corresponding to the distance to the upper surface of the lower mold 14 is equal to or substantially equal to the distance between the upper table 24 and the upper surface of the lower mold 14 before the lowering operation of the upper table 24 is started. It is in agreement. The predetermined third requirement is that the difference obtained by subtracting the detection value corresponding to the distance to the upper surface of the work W from the detection value corresponding to the distance to the upper surface of the lower mold 14 is the same as or substantially equal to the thickness of the work W. It is the same. When determining the predetermined third requirement from the predetermined first requirement, the detection value corresponding to the distance to the upper surface of the work W and the detection value corresponding to the distance to the upper surface of the lower mold 14 are, for example, average values. Use the value.

The permission signal output unit 44 turns on the safety signal when the work W on the lower mold 14 is determined to be appropriate. In other words, the permission signal output unit 44 outputs a permission signal for permitting the lowering operation of the upper table 24 when the work W on the lower mold 14 is determined to be appropriate.

As shown in FIG. 2 and FIGS. 6A and 6B, the entry determination unit 46 determines the upper die 12 and the lower die based on the detection values of the plurality of distance sensors 36 during the lowering operation of the upper table 24. It is determined whether or not the foreign matter E has entered between the mold 14.

Specifically, the entry determination unit 46 determines that one of the detection values of the plurality of distance sensors 36 corresponds to the detection value (dv1) corresponding to the distance to the upper surface of the work W and the upper surface of the lower mold 14. It is determined whether or not the detected value is a detected value (dve) corresponding to the distance to the foreign object E other than the detected value (dv2) corresponding to the distance. For example, in the case shown in FIGS. 6A and 6B, the entry determination unit 46 detects that the distance sensors 31f and 31g correspond to the distance to the foreign matter E among the detection values of the plurality of distance sensors 36c to 36j. It is determined that it is the value (dve), and it is determined that the foreign matter E has entered between the upper die 12 and the lower die 14.

When the entry determination unit 46 determines that one of the detection values of the plurality of distance sensors 36 is the detection value (dve) corresponding to the distance to the foreign object E, the entry determination unit 46 calculates the size of the foreign object E, By determining whether or not the size of E exceeds the allowable range, it is determined whether or not the foreign matter E has entered between the upper mold 12 and the lower mold 14. When the size of the foreign material E exceeds the allowable range, the entry determination unit 46 determines that the foreign material E has entered between the upper die 12 and the lower die 14. When the size of the foreign material E does not exceed the allowable range, the entry determination unit 46 determines that the foreign material E has not entered between the upper mold 12 and the lower mold 14.

Here, the size of the foreign matter E is the height and width of the foreign matter E, and the size of the foreign matter E exceeding the allowable range means that either the height or the width of the foreign matter E is within the allowable range (height). Or the allowable range of width). The height of the foreign matter E is calculated based on the detection value (dve) corresponding to the distance to the foreign matter E. The width of the foreign matter E is calculated based on the position in the width direction (left-right direction) of the distance sensor 36 that has detected the detection value (dve) corresponding to the distance to the foreign matter E. Note that only the height or width of the foreign matter E may be used as the size of the foreign matter E.

The stop signal output unit 48 turns off the safety signal when it is determined that the foreign matter E has entered between the upper mold 12 and the lower mold 14. In other words, the stop signal output unit 48 outputs a stop signal for stopping the lowering operation of the upper table 24 when it is determined that the foreign matter E has entered between the upper mold 12 and the lower mold 14. Output.

As shown in FIGS. 2 and 5A and 5B, in the warp determination unit 50, the group of the detection values of the plurality of distance sensors 36 (for example, 36c to 36j) corresponding to the width dimension of the work W is the work W. Whether the variation Δd of the detection values of the plurality of distance sensors 36 corresponding to the width dimension of the work W is within the permissible range as the warp of the work W when considered as a group of detection values corresponding to the distance to the upper surface. To determine.

As shown in FIGS. 2 and 7A and 7B, the detection value classification unit 40 determines that the variation Δd is not within the allowable range as the warp of the work W and the bending is box bending. The height of the flange F is calculated based on the detection values of the distance sensors 36 corresponding to both ends of W (upper and lower facing). The detection value classification unit 40 detects the distance sensors 36 corresponding to both end sides of the work W on condition that the calculated height of the flange F is the same as or substantially the same as the height dimension of the flange as the product information. Except for the values, the detection values of the plurality of distance sensors 36 corresponding to the width dimension of the work W are regarded as a group of detection values corresponding to the distance to the upper surface of the work. For example, in the case shown in FIGS. 7A and 7B, the detection value classification unit 40 includes a plurality of detection values of the plurality of distance sensors 36d to 36i excluding the detection values of the plurality of distance sensors 36d and 36i. The distance sensors 36e to 36h are regarded as a group of detection values corresponding to the distance to the upper surface of the work W. The detection value classification unit 40 regards the group of detection values of the plurality of distance sensors 36c and 36j as the group of detection values corresponding to the distance to the upper surface of the lower mold 14.

The detection value classification unit 40 determines the maximum detection value among the detection values of the plurality of distance sensors when the variation Δd is determined not to be within the allowable range as the warp of the work W and the bending is not box bending. It is considered as a group of detected values corresponding to the distance to the upper surface of 14. Further, the detection value classifying unit 40 regards the detection values close to the value obtained by subtracting the thickness dimension of the work W from the maximum detection value as a group of detection values corresponding to the distance to the upper surface of the work W, and the remaining detection values. It is regarded as a group of detection values corresponding to the distance to the foreign matter E. Further, when the remaining detection values are regarded as a group of detection values corresponding to the distance to the foreign matter E (see FIG. 6A), the approach determination unit 46 determines that before the lowering operation of the upper table 24 is started, It is determined whether or not the foreign matter E has entered between the upper die 12 and the lower die 14 by calculating the size of the foreign matter E and determining whether or not the size of the foreign matter E exceeds the allowable range. To do.

Next, the operation of the press brake 10 including the safety monitoring method according to the embodiment of the present invention will be described with reference to FIGS. 8A, 8B, 8C and the like. The safety monitoring method according to the embodiment of the present invention is a method for monitoring the presence or absence of the foreign matter E between the upper mold 12 and the lower mold 14. The safety monitoring method according to the embodiment of the present invention includes a distance detection step and an entry determination step.

The CPU of the monitoring controller 38 acquires mold information, work information, and product information from the control device 32 (step S101 in FIG. 8A). Next, the CPU of the monitoring controller 38 invalidates the detection of the distance sensors 36 other than the plurality of distance sensors 36 corresponding to the plurality of lower molds 14 among all the distance sensors 36 (step S102 in FIG. 8A). .. The plurality of distance sensors 36 detect vertical distances to the upper surface of the work W or the upper surface of the lower mold 14 (step S103 in FIG. 8A). Then, the detection value classification unit 40 classifies the detection values of the plurality of distance sensors 36 into a plurality of types according to the size (step S104 in FIG. 8A), and the CPU of the monitoring controller 38 further includes the plurality of distance sensors. It is determined whether or not the detection values of 36 are classified into two types, a detection value group corresponding to the distance to the upper surface of the work W and a detection value group corresponding to the distance to the upper surface of the lower mold 14 (FIG. 8A). Step S105).

When the detection values of the plurality of distance sensors 36 are classified into two types (Yes in step S105 in FIG. 8A), the appropriateness determining unit 42 determines whether the work W on the lower mold 14 is appropriate. It is determined whether or not (step S106 in FIG. 8A). When the work W on the lower die 14 is proper (Yes in step S106 in FIG. 8A), the permission signal output unit 44 turns on the safety signal (step S107 in FIG. 8A), in other words. Then, the permission signal for permitting the lowering operation of the upper table 24 is output. Then, the control device 32 controls the pair of lifting cylinders 28 to start the lowering operation of the upper table 24 (step S108 in FIG. 8A). Detection by the plurality of distance sensors 36 during the lowering operation of the upper table 24 is started (step S109 in FIG. 8B, distance detection step).
When the work W on the lower die 14 is not appropriate (No in step S106 in FIG. 8A), the CPU of the monitoring controller 38 generates an alarm indicating that an abnormality has occurred (in FIG. 8A). Step S110).

During the lowering operation of the upper table 24, the entry determination unit 46 determines whether any of the detection values of the plurality of distance sensors 36 is the detection value corresponding to the distance to the foreign matter E (step in FIG. 8B). S111, entry determination step). If any of the detection values of the plurality of distance sensors 36 is not the detection value (dve) corresponding to the distance to the foreign substance E (No in step S111 in FIG. 8B), the CPU of the monitoring controller 38 It is determined whether or not the bending process is completed (step S112 in FIG. 8C). Then, when the bending process is completed (in the case of Yes in step S112 in FIG. 8C), the CPU or the like of the monitoring controller 38 ends the series of processes. If the bending process is not completed (No in step S112 in FIG. 8C), the CPU of the monitoring controller 38 returns the process to step S111 in FIG. 8B.

When any of the detection values of the plurality of distance sensors 36 is the detection value (dve) corresponding to the distance to the foreign object E (in the case of Yes in step S111 in FIG. 8B), the entry determination unit 46 determines The size of the foreign matter E is calculated (step S113 in FIG. 8B), and it is determined whether the size of the foreign matter E exceeds the allowable range (step S114 in FIG. 8B). Then, when the size of the foreign matter E exceeds the allowable range (in the case of Yes in step S114 in FIG. 8B), the entry determination unit 46 causes the upper die 12 and the lower die to move during the lowering operation of the upper table 24. It is determined that the foreign matter E has entered between the mold 14 (step S115 in FIG. 8B). The stop signal output unit 48 turns off the safety signal (step S116 in FIG. 8B), in other words, outputs a stop signal for stopping the lowering operation of the upper table 24. Then, the controller 32 controls the pair of lifting cylinders 28 to stop the lowering operation of the upper table 24 (step S117 in FIG. 8B). The CPU of the monitoring controller 38 generates an alarm indicating that an abnormality has occurred (step S118 in FIG. 8B).

If the size of the foreign matter E does not exceed the allowable range (No in step S114 in FIG. 8B), the CPU of the monitoring controller 38 returns the process to step S111 in FIG. 8B.

On the other hand, when the detection values of the plurality of distance sensors 36 are not classified into two types (No in step S105 in FIG. 8A ), the detection value classification unit 40 determines the plurality of detection values corresponding to the width dimension of the work W. The detection values of the distance sensor 36 are regarded as a group of detection values corresponding to the distance to the upper surface of the work W. The detection value classification unit 40 regards the detection values of the other distance sensors 36 as a group of detection values corresponding to the distance to the upper surface of the lower mold 14 (step S119 in FIG. 8A). Then, the warp determination unit 50 determines whether or not the variation Δd in the detection values of the plurality of distance sensors 36 corresponding to the width dimension of the work W is within the allowable range as the warp of the work W (step S120 in FIG. 8A). .. If the variation Δd is within the allowable range (Yes in step S120 in FIG. 8A), the CPU of the monitoring controller 38 shifts the processing to step S106 in FIG. 8A.

If the variation Δd is not within the allowable range (No in step S120 in FIG. 8A), the CPU of the monitoring controller 38 determines whether the bending work is box bending (step S121 in FIG. 8C). When the bending process is box bending (Yes in step S121 in FIG. 8C), the detection value classification unit 40 determines the flange F based on the detection values of the distance sensors 36 corresponding to both end sides of the work W. The height of the is calculated (step S122 in FIG. 8C). The detection value classification unit 40 determines whether the height of the flange F is the same as or substantially the same as the height dimension of the flange as the product information (step S123 in FIG. 8C).

When the height of the flange F is the same as or substantially the same as the height dimension of the flange as the product information (Yes in step S123 in FIG. 8C ), the detection value classification unit 40 determines that both ends of the work W are located. The detection values of the plurality of distance sensors 36 corresponding to the width dimension of the work W, excluding the detection values of the distance sensor 36 corresponding to, are regarded as a group of detection values corresponding to the distance to the upper surface of the work (step S124 in FIG. 8C). ). The CPU of the monitoring controller 38 shifts the processing to step S106 in FIG. 8A.

If the height of the flange F is not the same as or substantially the same as the height dimension of the flange as the product information (No in step S123 in FIG. 8C), the CPU of the monitoring controller 38 indicates that an abnormality has occurred. Is generated (step S110 in FIG. 8A).

When the bending is not box bending (No in step S121 in FIG. 8C), the detection value classification unit 40 sets the maximum detection value among the detection values of the plurality of distance sensors to the upper surface of the lower mold 14. It is regarded as a group of detected values corresponding to the distance of. Further, the detection value classification unit 40 regards a detection value close to a value obtained by subtracting the thickness dimension of the work W from the maximum detection value as a group of detection values corresponding to the distance to the upper surface of the work W (step S125 in FIG. 8C). ). Then, the detection value classification unit 40 determines whether or not the difference between the maximum detection value and the close detection value is the same as the thickness dimension of the work W (step S126 in FIG. 8C). When the difference between the maximum detection value and the close detection value is the same as the thickness dimension of the work W (Yes in step S126 in FIG. 8C), the detection value classification unit 40 determines the remaining detection values as foreign matter. It is regarded as a group of detected values corresponding to the distance to E (step S127 in FIG. 8C).

After that, the entry determination unit 46 calculates the size of the foreign matter E (step S128 in FIG. 8C) and determines whether the size of the foreign matter E exceeds the allowable range (step S129 in FIG. 8C). Then, when the size of the foreign matter E exceeds the allowable range (Yes in step S129 in FIG. 8B), the entry determination unit 46 sets the upper die 12 and the lower die 12 before the lowering operation of the upper table 24 is started. It is determined that the foreign material E has entered between the mold 14 (step S130 in FIG. 8C). The CPU of the monitoring controller 38 generates an alarm indicating that an abnormality has occurred (step S110 in FIG. 8A). If the size of the foreign matter E does not exceed the allowable range (No in step S129 in FIG. 8B), the CPU of the monitoring controller 38 shifts the processing to step S106 in FIG. 8A.

If the difference between the maximum detection value and the close detection value is not the same as the thickness dimension of the work W (No in step S126 in FIG. 8C), the CPU of the monitoring controller 38 indicates that an abnormality has occurred. Is generated (step S110 in FIG. 8A).

Next, the function and effect of the embodiment of the present invention will be described.

As described above, during the lowering operation of the upper table 24, the entry determination unit 46 determines whether any of the detection values of the plurality of distance sensors 36 is the detection value corresponding to the distance to the foreign matter E. Thus, it is determined whether or not the foreign matter E has entered between the upper mold 12 and the lower mold 14. Thereby, the entry of the foreign matter E between the upper mold 12 and the lower mold 14 is monitored based on the detection values of the plurality of distance sensors 36 without using the monitoring light projected along the width direction. can do.

Therefore, without considering the enlargement of the shadow of the upper die 12, if the foreign matter E is present on or near the lower die 14, the upper die 12 approaches the lower die 14. Even if it does not exist, it can be determined that a foreign matter has entered between the upper mold 12 and the lower mold 14. Therefore, according to the embodiment of the present invention, it is possible to secure the safety of the bending work at a high level while suppressing the complexity of the bending work. In particular, since the entry determination unit 46 calculates the size of the foreign matter E and determines whether or not the size of the foreign matter E exceeds the allowable range, the approach determination unit 46 is placed between the upper mold 12 and the lower mold 14. It is possible to accurately determine whether or not the foreign matter E has entered.

Even if the work W has the flange F, if the foreign matter E exists between the upper die 12 and the work W, the foreign matter is present between the upper die 12 and the lower die 14. It can be determined that it has entered. Therefore, according to the embodiment of the present invention, the safety of the bending work can be ensured at a high level even when the box bending of the work W is performed.

As described above, before the lowering operation of the upper table 24 is started, the plurality of distance sensors 36 detect the vertical distance to the upper surface of the work W or the upper surface of the lower mold 14. Therefore, according to the embodiment of the present invention, it is possible to detect the thickness of the work W and determine whether the warp of the work W is within the allowable range, and the effective use of the press brake safety device 34 is possible. Can be planned.

The present invention is not limited to the above description of the embodiments, but can be implemented in various other modes by making appropriate changes. The scope of rights included in the present invention is not limited to the above embodiment.

10 Press Brake 12 Upper Die 14 Lower Die 16 Main Frame 18 Side Plate 20 Lower Table 22 Lower Die Holder 24 Upper Table 26 Upper Die Holder 28 Lift Cylinder 30 Back Gauge 32 Control Device 34 Press Brake Safety Device 36 ( 36a to 36l) Distance sensor 38 Monitoring controller 40 Detected value classification unit 42 Appropriate determination unit 44 Permit signal output unit 46 Entry determination unit 48 Stop signal output unit 50 Warp determination unit

Claims (11)

A plurality of distance sensors provided along the width direction at a position above the lower mold in the press brake, and detecting a distance to the upper surface of the work or the upper surface of the lower mold,
An entry determination unit that determines whether or not a foreign object has entered between the upper die and the lower die based on the detection values of the plurality of distance sensors during the lowering operation of the upper table relative to the lower table. And a safety device for a press brake, which is characterized by having The entry determination unit is configured such that one of the detection values of the plurality of distance sensors is a foreign matter other than the detection value corresponding to the distance to the upper surface of the work and the detection value corresponding to the distance to the upper surface of the lower mold. 2. It is determined whether or not a foreign object has entered between the upper die and the lower die by determining whether or not the detected value corresponds to the distance up to. Safety device for press brakes. The entry determination unit calculates the size of the foreign matter and determines the size of the foreign matter when it determines that one of the detection values of the plurality of distance sensors is a detection value corresponding to the distance to the foreign matter. The press brake safety according to claim 2, wherein it is determined whether or not a foreign matter has entered between the upper mold and the lower mold by determining whether or not the allowable range is exceeded. apparatus. And a stop signal output unit for outputting a stop signal for stopping the relative lowering operation of the upper table when it is determined that a foreign object has entered between the upper mold and the lower mold. The safety device for a press brake according to any one of claims 1 to 3, wherein the safety device is for a press brake. Before the relative lowering operation of the upper table is started, a detection value classification unit that classifies detection values of the plurality of distance sensors into a plurality of types according to the size,
When the detection values of the plurality of distance sensors are classified into two types, a detection value group corresponding to the distance to the upper surface of the work and a detection value group corresponding to the distance to the upper surface of the lower mold, or 2 An appropriateness determination unit that determines whether or not the work on the lower die is appropriate when it is considered that the workpieces are classified into types, and the appropriateness determination unit is provided. The safety device for a press brake according to any one of items. A permission signal output unit for outputting a permission signal for permitting a relative lowering operation of the upper table when it is determined that the work on the lower mold is appropriate. The safety device for a press brake according to Item 5. The detection value classifying unit classifies the detection values of the plurality of distance sensors into two types: a group of detection values corresponding to the distance to the upper surface of the work and a group of detection values corresponding to the distance to the upper surface of the lower mold. If not possible, the detection values of the plurality of distance sensors corresponding to the width dimension of the work are regarded as a group of detection values corresponding to the distance to the upper surface of the work, and the detection values of the other distance sensors are the lower mold. Regarded as a group of detected values corresponding to the distance to the upper surface of
Furthermore, a warp determination unit that determines whether or not variations in the detection values of the plurality of distance sensors corresponding to the width dimension of the work are within an allowable range as the warp of the work is provided. Item 6. A safety device for a press brake according to Item 6. The detection value classification unit classifies the detection values of the plurality of distance sensors into two types, a detection value group corresponding to the distance to the upper surface of the work and a detection value group corresponding to the distance to the upper surface of the lower mold. If it is not possible, the detection value of the plurality of distance sensors corresponding to the width dimension of the work is excluded, excluding the detection value of the distance sensor corresponding to the end side of the work, provided that the bending process is box bending. Considered as a group of detection values corresponding to the distance to the upper surface of the work, detection values other than the detection values of the plurality of distance sensors corresponding to the width dimension of the work are detected values corresponding to the distance to the upper surface of the lower mold. The safety device for a press brake according to any one of claims 5 to 7, characterized in that the safety device is regarded as a group. The detection value classification unit classifies the detection values of the plurality of distance sensors into two types, a detection value group corresponding to the distance to the upper surface of the work and a detection value group corresponding to the distance to the upper surface of the lower mold. When it is not possible, among the detection values of the plurality of distance sensors, the maximum detection value is regarded as a group of detection values corresponding to the distance to the upper surface of the lower mold, and the thickness dimension of the workpiece is calculated from the maximum detection value. The detected values close to the subtracted value are regarded as a group of detected values corresponding to the distance to the upper surface of the workpiece, and the remaining detected values are regarded as a group of detected values corresponding to the distance to the foreign matter,
Before the relative lowering operation of the upper table is started, the entry determination unit calculates the size of the foreign matter, and determines whether the calculated size of the foreign matter exceeds the allowable range, thereby the upper metal The press brake safety device according to claim 5, wherein it is determined whether or not a foreign matter has entered between the mold and the lower mold. A press brake comprising the press brake safety device according to any one of claims 1 to 9. Using a plurality of distance sensors that are provided above the lower die in the press brake along the width direction and that detect the distance to the upper surface of the work or the upper surface of the lower die,
A safety monitoring method for determining whether or not a foreign object has entered between the upper mold and the lower mold based on the detection values of the plurality of distance sensors during the lowering operation of the upper table relative to the lower table. ..

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