Abutment adjustment method and press brake

Abstract

This press brake (1) comprises: a press brake body (10) that bends a workpiece along a bending line extending in the left-right direction; a back gauge (30) that is disposed behind the press brake body (10) and comprises abutments (42a, 42b) that an end of the workpiece butts against to position the workpiece; and a guard (50) that is provided to surround a rear region of the press brake body (10) including the back gauge (30) and restricts entry into the rear region. This butting adjustment method includes: a first This abutment adjustment method includes: a first step for moving abutments (42a, 42b) rearward by operating a Y-axis actuator (34); and a second step for adjusting the positions of the abutments (42a, 42b) in the left-right direction by manually moving the abutments (42a, 42b) in the left-right direction from an access region in which the restriction of a guard has been released.

Description

Method for Adjusting Stop and Press Brake

[0001] The present disclosure relates to a method for adjusting a stop and a press brake.

[0002] Patent Document 1 discloses a press brake provided with a back gauge that is arranged behind upper and lower tables and positions a workpiece to be processed. This back gauge includes a stop that can be manually moved along a guide track extending in the left - right direction. An operator needs to adjust the position of the stop according to the processing.

[0003] European Patent No. 2881188 Specification

[0004] However, a guard for restricting the entry of an operator is provided in the rear area of the press brake including the back gauge. The operator had to enter the inside of the guard with the restriction of the guard properly released, approach the back gauge, and then adjust the position of the stop. Therefore, the adjustment work of the stop was time - consuming and a great burden on the operator.

[0005] One aspect of one or more embodiments is a press brake comprising a press brake body that bends a workpiece along a bending line extending in the left - right direction, a back gauge arranged behind the press brake body and provided with a stop for positioning the workpiece by abutting the edge of the workpiece, and a guard provided so as to surround the rear area of the press brake body including the back gauge and restricting entry into the rear area. In the press brake, it is a method for adjusting the position of the stop. This adjustment method includes a first step of moving the stop backward by operating an actuator, and a second step of an operator outside the guard manually moving the stop in the left - right direction from an access area where the restriction of the guard is released to adjust the position of the stop in the left - right direction.

[0006] Figure 1 is a front view of the press brake according to this embodiment. Figure 2 is a rear view of the press brake according to this embodiment, showing the opening in a closed state. Figure 3 is a rear view of the press brake according to this embodiment, showing the opening in an open state. Figure 4 is a perspective view showing the back gauge. Figure 5 is a first diagram showing a method for adjusting the stopper. Figure 6 is a second diagram showing a method for adjusting the stopper. Figure 7 is a third diagram showing a method for adjusting the stopper. Figure 8 is a fourth diagram showing a method for adjusting the stopper. Figure 9 is a fifth diagram showing a method for adjusting the stopper. Figure 10 is a diagram showing a modified example of the door.

[0007] The adjustment method for the press brake and stopper according to this embodiment will be described below with reference to the drawings.

[0008] Referring to Figures 1 to 3, the configuration of the press brake 1 according to this embodiment will be described. In this specification, the directions used in the press brake 1 are defined as left-right direction, front-back direction, and up-down direction. The left-right direction and front-back direction correspond to two orthogonal directions in the horizontal plane, and the up-down direction corresponds to the vertical direction. In Figure 1, the vertical direction of the paper corresponds to the front-back direction, with the direction away from the paper being the front direction and the direction approaching the paper being the rear direction. In Figures 2 and 3, the vertical direction of the paper corresponds to the front-back direction, with the direction away from the paper being the rear direction and the direction approaching the paper being the front direction. However, these directions are used only for convenience in explaining the bending system. In the drawings, the right direction, left direction, up direction, down direction, front direction, and rear direction are indicated by RT, LT, UP, DN, FR, and RR, respectively.

[0009] As shown in Figure 1, the press brake 1 comprises a press brake body 10, a back gauge 30, a guard 50, and a control device 100.

[0010] The press brake body 10 is a processing machine that bends sheet metal or other plate-shaped workpieces along a bending line extending in the left-right direction through the cooperation of a lower die 17 such as a die and an upper die 18 such as a punch. The press brake body 10 comprises left and right side plates 11 and 12, a lower table 13, an upper table 14, and left and right table drive devices 19 and 20.

[0011] The left and right side plates 11 and 12 are positioned so as to face each other and are separated in the left-right direction.

[0012] The lower table 13 extends in the left-right direction and is supported by the front lower parts of the left and right side plates 11 and 12. Above the lower table 13, a lower mold holder 15 is provided along the left-right direction for detachably holding the lower mold 17.

[0013] The upper table 14 extends in the left-right direction and is supported on the front upper part of the left and right side plates 11 and 12 so as to face the lower table 13. The upper table 14 is configured to be movable in the vertical direction relative to the left and right side plates 11 and 12. An upper mold holder 16 for detachably holding the upper mold 18 is provided on the lower side of the upper table 14 along the left-right direction.

[0014] The left and right table drive units 19 and 20 are fixed to the upper parts of the left and right side plates 11 and 12, respectively. Each table drive unit 19 and 20 is a drive unit that moves the upper table 14 in the vertical direction. For example, the table drive units 19 and 20 mainly consist of an electric motor that provides rotational drive and a ball screw mechanism that converts the rotational motion of the electric motor into linear motion. The table drive units 19 and 20 may also be composed of hydraulic actuators.

[0015] The back gauge 30 is positioned behind the press brake body 10, specifically behind the lower and upper tables 13 and 14. The back gauge 30 positions the workpiece by abutting the trailing edge of the workpiece against it.

[0016] As shown in Figure 4, the back gauge 30 comprises a rectangular frame 31, a Y-axis carriage 35, left and right Z-axis carriages 36a and 36b, an X-axis beam 40, and left and right abutments 42a and 42b.

[0017] The rectangular frame 31 is mounted on a support frame 21 (see Figure 3) that spans across the left and right side plates 11 and 12 of the press brake body 10. The rectangular frame 31 is composed of a rectangular frame. Of the rectangular frame 31, the straight frames 31a and 31b located on the left and right sides are provided with Y-axis guide rails 32a and 32b that extend in the front-rear direction. The rectangular frame 31 is provided with a Y-axis actuator 34 for moving the Y-axis carriage 35 in the front-rear direction. For example, the Y-axis actuator 34 comprises an electric motor and a ball screw mechanism.

[0018] The Y-axis carriage 35 is mounted on the left and right straight frames 31a and 31b. The Y-axis carriage 35 can move in the forward and backward direction by being guided by the Y-axis guide rails 32a and 32b. The Y-axis carriage 35 moves in the forward and backward direction when the Y-axis actuator 34 is operated. Z-axis carriages 36a and 36b are positioned at the left and right ends of the Y-axis carriage 35. The Z-axis carriages 36a and 36b are provided with Z-axis guide rails 37a and 37b that extend in the vertical direction. The left and right Z-axis guide rails 37a and 37b are held movably by guide members fixed to the left and right ends of the Y-axis carriage 35. The Z-axis carriages 36a and 36b can move in the vertical direction by being guided by the Z-axis guide rails 37a and 37b.

[0019] The X-axis beam 40 extends in the left-right direction. The X-axis beam 40 is horizontally supported by Z-axis carriages 36a and 36b. A Z-axis actuator 37 is provided in the center of the X-axis beam 40 to move the X-axis beam 40 in the vertical direction. For example, the Z-axis actuator 37 comprises an electric motor and a ball screw mechanism. When the Z-axis actuator 37 operates, the X-axis beam 40 moves in the vertical direction. At this time, the vertical movement of the X-axis beam 40 is guided by the Z-axis carriages 36a and 36b.

[0020] The left and right abutments 42a and 42b are components against which the trailing edge of a workpiece abuts when positioning the workpiece. The left and right abutments 42a and 42b are provided on the X-axis beam 40. The left and right abutments 42a and 42b are configured to slide on the X-axis beam 40. The left and right abutments 42a and 42b are not moved by actuators, but are moved in the left and right direction by manual operation by an operator. Therefore, the operator needs to adjust the position of the left and right abutments 42a and 42b according to the size of the workpiece. The X-axis beam 40 is provided with a scale 41 that serves as a guide when adjusting the position of the left and right abutments 42a and 42b.

[0021] In a back gauge 30 with this configuration, the control device 100 controls the Y-axis and Z-axis actuators 34 and 37, thereby moving the X-axis beam 40 and the left and right abutments 42a and 42b provided on the X-axis beam 40 in the front-rear and up-down directions. The front-rear and up-down positions of the abutments 42a and 42b are adjusted by the operation of the Y-axis and Z-axis actuators 34 and 37. On the other hand, the left-right positions of the left and right abutments 42a and 42b are manually adjusted by an operator.

[0022] As shown in Figures 1 and 2, the guard 50 is provided to surround the rear area of ​​the press brake body 10. The rear area is the area located behind the lower and upper tables 13 and 14, and this rear area also includes the back gauge 30. The guard 50 restricts the entry of workers into the rear area. In this embodiment, the guard 50 is composed of plates that physically restrict the entry of workers.

[0023] The guard 50 comprises a left guard 51, a right guard 52, and a rear guard 53. The left guard 51 is located on the left side of the press brake body 10 and is positioned to cover an open area provided on the left side plate 11 of the press brake body 10. The right guard 52 is located on the right side of the press brake body 10 and is positioned to cover an open area provided on the right side plate 12 of the press brake body 10.

[0024] The rear guard 53 is positioned behind the press brake body 10, specifically behind the back gauge 30, and is provided to cover the open area between the left and right side plates 11 and 12. The rear guard 53 comprises a base panel 54 with an opening 55 in the center, and left and right doors 56 and 57 that open and close the opening 55. As shown in Figure 3, the length L from the lower end of the base panel 54 to the lower end of the opening 55 is designed assuming that a worker will step over and enter the guard 50 during maintenance work. Specifically, it is set to be approximately the same height as the support frame 21 on which the back gauge 30 is mounted.

[0025] As shown in Figure 2, the left door 56 covers the left half of the opening 55 from the center and is a sliding door consisting of two panels. By moving the left door 56 to the open position on the left side, the left half of the opening 55 from the center can be opened. The right door 57 covers the right half of the opening 55 from the center and is a sliding door consisting of two panels. By moving the right door 57 to the open position on the right side, the right half of the opening 55 from the center can be opened. The opening 55 can be opened or closed by moving one or both of the left and right doors 56 and 57. When one or both of the left and right doors 56 and 57 are in the open position, the restriction on the opening 55 is released. Even when outside the guard 50, a worker can access the inside of the guard 50 by inserting their upper limbs through the opening 55. In other words, the opening 55 corresponds to an access area for a worker to access the inside of the guard 50. Furthermore, by making the left and right doors 56 and 57 sliding doors composed of two panels, the size of the opening 55 can be increased.

[0026] The control device 100 controls the operation of the press brake body 10 and the back gauge 30. The control device 100 is a computer, such as an NC (Numerical Control) device. The computer mainly consists of a hardware processor such as a CPU (Central Processing Unit), memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus.

[0027] The computer's memory stores a predetermined computer program. The hardware processor executes this computer program, thereby enabling the computer to perform multiple functions provided by the control unit 100.

[0028] In this embodiment, the control device 100 controls the vertical movement of the upper table 14 by controlling the left and right table drive devices 19 and 20. The control device 100 also controls the front-to-back and vertical positions of the left and right abutments 42a and 42b by controlling the Y-axis and Z-axis actuators 34 and 37.

[0029] Furthermore, as shown in Figure 2, sensors 26 are provided on the left and right doors 56 and 57 of the rear guard 53. The control device 100 receives detection signals from the sensors 26. The sensors 26 detect when one or both of the left and right doors 56 and 57 move from the closed position, that is, when one or both of the left and right doors 56 and 57 are opened. Based on the detection signals from the sensors 26, the control device 100 can determine that one or both of the left and right doors 56 and 57 have been opened, that is, when the restriction of the guard 50 on the opening 55 has been released.

[0030] When performing bending using the press brake 1 configured in this way, the operator stands in front of the press brake body 10 and inserts the workpiece from front to rear into the space between the lower table 13 and the upper table 14, placing the workpiece on the lower die 17 mounted on the lower table 13. At this time, the operator positions the workpiece by abutting the rear edge of the workpiece against the abutments 42a and 42b of the back gauge 30 so that the bending line of the workpiece coincides with the bending position of the press brake body 10. Then, the control device 100 receives a trigger from the operator and lowers the upper table 14 toward the lower table 13. As a result, the workpiece is pressed between the lower die 17 and the upper die 18, and the workpiece is bent at the desired bending angle along the bending line.

[0031] The method for adjusting the positions of the abutments 42a and 42b according to this embodiment will be described below with reference to Figures 5 to 9. In this description, we assume a scenario in which the positions of the left and right abutments 42a and 42b are adjusted in accordance with the second bending process after the first bending process has been performed on the workpiece. Therefore, the left and right abutments 42a and 42b are currently in the positions corresponding to the first bending process. Also, as shown in Figure 5, the left and right doors 56 and 57 of the rear guard 53 are in the closed position, and the opening 55 is closed.

[0032] As shown in Figure 6, the control device 100 controls the Y-axis actuator 34 to move the left and right abutments 42a and 42b backward from their previous (first) machining positions. Specifically, the control device 100 moves the left and right abutments 42a and 42b to the retracted position, which is the furthest rearward position within their movable range.

[0033] As shown in Figure 7, when the left and right abutments 42a and 42b move to the retracted position, the worker stands behind the rear guard 53 and moves the left and right doors 56 and 57 to the open position. When the left and right doors 56 and 57 move to the open position, the sensor 26 outputs a detection signal indicating that the left and right doors 56 and 57 are open. When the control device 100 determines that the left and right doors 56 and 57 have been opened based on the control signal, it puts the press brake 1 to an emergency stop.

[0034] As shown in Figure 8, a worker positioned behind the rear guard 53 can access the inside of the guard 50 by inserting their upper limbs through the opening 55 and adjust the left-right positions of the left and right abutments 42a and 42b. At this time, since the worker can access the inside of the guard 50 through the opening 55, the position of the left and right abutments 42a and 42b can be adjusted even when the worker is outside the guard 50. In addition, the left and right abutments 42a and 42b have been moved to their retracted positions in advance and are closer to the rear guard 53. As a result, the left and right abutments 42a and 42b are within reach of the worker's upper limbs, allowing the worker to adjust the position of the left and right abutments 42a and 42b in a comfortable posture.

[0035] Once the positions of the left and right abutments 42a and 42b have been adjusted, the operator moves the left and right doors 56 and 57 to the closed position, as shown in Figure 9. As a result, the opening 55 is closed by the left and right doors 56 and 57. A detection signal indicating the closed state of the doors 56 and 57 is input from the sensor 26 to the control device 100. Based on the control signal, the control device 100 determines that the left and right doors 56 and 57 are closed and returns the press brake 1 to the operating state. The control device 100 also controls the Y-axis actuator 34 to move the left and right abutments 42a and 42b forward according to the processing position for the current (second) processing, positioning the left and right abutments 42a and 42b at predetermined positions in the front-rear direction.

[0036] Through the above series of steps, the left and right abutments 42a and 42b are appropriately positioned to correspond to the second bending process.

[0037] Thus, the method for adjusting the abutments in this embodiment includes a first step of moving the left and right abutments 42a and 42b backward by operating the Y-axis actuator 34, and a second step of adjusting the positions of the abutments 42a and 42b in the left-right direction by manually moving the left and right abutments 42a and 42b in the left-right direction from the access area where the restriction of the guard 50 has been released.

[0038] According to this method, the worker can access the inside of the guard 50 from the access area, so the worker can adjust the positions of the left and right abutments 42a and 42b even while the worker is outside the guard 50. Also, since the left and right abutments 42a and 42b have moved backward, they are closer to the rear guard 53. As a result, the left and right abutments 42a and 42b are within the reach of the worker's upper limbs, so the worker can adjust the positions of the left and right abutments 42a and 42b in a comfortable posture. Therefore, the adjustment work of the left and right abutments 42a and 42b can be performed quickly, reducing the burden on the worker.

[0039] In the method for adjusting the abutment of the present embodiment, the second step further includes releasing the restriction in the access area.

[0040] According to this method, when the left and right abutments 42a and 42b are not adjusted, the access area is restricted, so the safety of the press brake 1 can be enhanced. Also, by releasing the restriction in the access area, the operator can properly enter the inside of the guard 50, so the operator can adjust the left and right abutments 42a and 42b from the access area.

[0041] In the method for adjusting the abutment of the present embodiment, the guard 50 includes an opening 55 that is the access area and left and right doors 56 and 57 that open and close the opening 55. In this case, the step of releasing the restriction in the access area is to move the left and right doors 56 and 57 to open the opening 55.

[0042] According to this method, by opening the opening 55, access can be made from the opening 55 to the inside of the guard 50. Thereby, even when the operator is outside the guard 50, the operator can easily adjust the positions of the left and right abutments 42a and 42b.

[0043] The method for adjusting the abutment of the present embodiment further includes a third step of bringing the press brake 1 to an emergency stop when the restriction in the opening 55 (access area) is released.

[0044] According to this method, when access from the opening 55 to the inside of the guard 50 becomes possible, the press brake 1 is brought to an emergency stop. Thereby, the safety when the operator manually moves the left and right abutments 42a and 42b can be ensured.

[0045] In the method for adjusting the abutment of the present embodiment, the guard 50 includes a sensor 26 that detects the movement of the left and right doors 56 and 57. The third step includes determining that the restriction in the access area has been released when the movement of the left door 56 is detected by the sensor 26.

[0046] According to this method, by referring to the detection result of the sensor 26, it is possible to accurately detect that the restriction in the access area has been released.

[0047] In the method for adjusting the abutment of the present embodiment, the guard 50 includes a right guard 52 provided on the right side of the press brake main body 10, a left guard 51 provided on the left side of the press brake main body 10, and a rear guard 53 provided behind the press brake main body 10. The opening 55 is provided in the rear guard 53.

[0048] According to this method, since the opening 55 is provided in the rear guard 53 located on the side where the abutments 42a and 42b move by the Y-axis actuator 34, the operator can operate the abutments 42a and 42b from a position close to the abutments 42a and 42b. Thereby, the operator can easily adjust the positions of the left and right abutments 42a and 42b with a reasonable posture.

[0049] In the method for adjusting the abutment of the present embodiment, in the first step, the left and right abutments 42a and 42b are moved to the retracted position that is the most rearward within the movable range of the left and right abutments 42a and 42b.

[0050] According to this method, since the abutments 42a and 42b are moved to a position close to the operator, the operator can easily operate the left and right abutments 42a and 42b.

[0051] Further, the press brake 1 of the present embodiment includes a press brake main body 10 that bends a workpiece along a bending line extending in the left-right direction, left and right abutments 42a and 42b that position the workpiece by abutting against the edge of the workpiece, and are disposed behind the press brake main body 10, a guard 50 that is provided so as to surround the rear region of the press brake main body 10 including the back gauge 30 and restricts entry into the rear region, and a control device 100. When the control device 100 determines that the abutments 42a and 42b have moved rearward to a position where they can be operated by an operator outside the guard and the restriction of the guard 50 has been released in the accessible area accessible to the operator, the press brake main body 10 is brought to an emergency stop.

[0052] With this configuration, the worker can access the inside of the guard 50 from the access area, so even if the worker is outside the guard 50, they can adjust the left and right positions of the left and right abutments 42a and 42b. Also, since the left and right abutments 42a and 42b have moved backward, they are closer to the rear guard 53. As a result, the left and right abutments 42a and 42b are within the reach of the worker's upper limbs, so the worker can adjust the positions of the left and right abutments 42a and 42b in a comfortable posture. Therefore, the adjustment work of the abutments 42a and 42b can be performed quickly, reducing the burden on the worker.

[0053] In the press brake 1 of this embodiment, the guard 50 includes an opening 55 which is an access area, and left and right doors 56 and 57 which open and close the opening 55. The restriction of the guard 50 is released by moving the left and right doors 56 and 57 to open the opening 55.

[0054] With this configuration, the opening 55 can be opened, allowing the worker to access the inside of the guard 50 through the opening 55, even if the worker is outside the guard 50. This allows the worker to easily adjust the positions of the left and right abutments 42a and 42b.

[0055] In the press brake 1 of this embodiment, the guard 50 is equipped with a sensor 26 that detects the movement of the left and right doors 56 and 57. When the sensor 26 detects the movement of the left and right doors 56 and 57, the control device 100 determines that the restriction of the guard has been released.

[0056] With this configuration, by referring to the detection results of the sensor 26, it is possible to accurately detect when the restrictions in the access area have been lifted.

[0057] In the press brake 1 of this embodiment, the guard 50 includes a left guard 51 provided on the left side of the press brake body 10, a right guard 52 provided on the right side of the press brake body 10, and a rear guard 53 provided behind the press brake body 10. The opening 55 is provided in the rear guard 53.

[0058] With this configuration, since an opening 55 is provided in the rear guard 53 located on the side where the abutments 42a and 42b move due to the Y-axis actuator 34, the operator can operate the abutments 42a and 42b from a position close to them. As a result, the operator can easily adjust the positions of the left and right abutments 42a and 42b in a comfortable posture.

[0059] In the press brake 1 of this embodiment, the back gauge 30 further comprises an X-axis beam 40 extending in the left-right direction. The abutments 42a and 42b are slidably arranged on the X-axis beam 40 in the left-right direction.

[0060] With this configuration, the operator can manually move the abutments 42a and 42b.

[0061] In the press brake 1 of this embodiment, the back gauge 30 is further equipped with a Y-axis actuator 34 that moves the X-axis beam 40 in the front-rear direction. The control device 100 controls the Y-axis actuator 34 to move the abutments 42a and 42b backward from the opening 55 to a position where an operator can operate them.

[0062] In this configuration, the rearward movement of the abutments 42a and 42b is achieved by the Y-axis actuator 34. This allows the abutments 42a and 42b to be automatically moved to a position where they can be operated by the operator.

[0063] In the press brake 1 of this embodiment, the left and right doors 56 and 57 are configured to slide along the left-right direction.

[0064] This configuration allows the left and right doors 56 and 57 to move parallel to the rear guard 53. Therefore, compared to a method where the doors move back and forth like a hinged door, the rearward protrusion when opening the opening 55 can be suppressed. This makes it possible to miniaturize the device.

[0065] In this embodiment, the doors that restrict the opening 55 are exemplified as left and right doors 56 and 57 of the double-leaf type. However, as shown in Figure 10, the doors that restrict the opening 55 may also be single-leaf doors 58. Furthermore, in this embodiment, the doors that restrict the opening 55 slide in the left-right direction, but the doors that restrict the opening 55 may also slide in the up-down direction.

[0066] Furthermore, in this embodiment, an opening 55 provided in the rear guard 53 is exemplified as the access area. However, the access area is not limited to this, as long as an operator can operate the abutments 42a and 42b from outside the guard 50. In addition, although a physical panel is exemplified as the guard 50 in this embodiment, the guard 50 may also be configured to restrict entry by light rays.

[0067] Furthermore, in this embodiment, the worker manually moves the left and right abutments 42a and 42b. As a method of manual movement, it is assumed that the worker moves the abutments 42a and 42b by directly touching them with their hands, but the worker may also move the abutments 42a and 42b by grasping a tool such as a rod and pressing the tool against the abutments 42a and 42b.

[0068] As described above, this embodiment has been presented, but the statements and drawings that constitute part of this disclosure should not be understood as limiting this disclosure. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure.

[0069] The disclosures of this application are related to the subject matter described in Japanese Patent Application No. 2024-220633, filed with the Japan Patent Office on 17 December 2024, and all of the disclosures herein are incorporated herein by reference.

Claims

A press brake body that bends the workpiece along a bending line extending in the left-right direction, The press brake body is equipped with a back gauge positioned behind the press brake body, which is used to position the workpiece by abutting the edge of the workpiece against it. A press brake comprising a guard provided so as to surround the rear region of the press brake body including the back gauge and restricting entry into the rear region, wherein a method for adjusting the position of the abutment is provided, A first step involves moving the stopper backward by operating the actuator, A second step involves a worker outside the guard manually moving the abutment in the left-right direction from the access area where the guard's restriction has been released, thereby adjusting the position of the abutment in the left-right direction. A method for adjusting the stopper, including the stopper itself. 　 The second step further includes the worker releasing the restrictions in the access area. The method for adjusting the stopper according to claim 1. 　 The system further includes a third step of emergency stopping the press brake when the restriction in the access area is released. The method for adjusting the stopper according to claim 2. 　 The guard comprises an opening which is the access area and a movable door which opens and closes the opening. The step of releasing the restrictions in the access area is for the worker to move the door to open the opening. The method for adjusting the abutment according to claim 3. 　 The guard is equipped with a sensor that detects the movement of the door, The third step includes determining that the restriction in the access area has been released when the movement of the door is detected by the sensor. The method for adjusting the stopper according to claim 4. 　 The guard includes a right guard provided on the right side of the press brake body, a left guard provided on the left side of the press brake body, and a rear guard provided behind the press brake body. The aforementioned opening is provided in the rear guard, The method for adjusting the stopper according to claim 4. 　 The first step is to move the stopper to the rearmost retraction position within the range of motion. The method for adjusting the stopper according to claim 1. 　 A press brake body that bends the workpiece along a bending line extending in the left-right direction, The press brake body is equipped with a back gauge positioned behind the press brake body, which is used to position the workpiece by abutting the edge of the workpiece against it. A guard is provided so as to surround the rear area of ​​the press brake body, including the back gauge, and restricts entry into the rear area. A control device is provided, The control device is When the stopper moves backward to a position where it can be operated by an operator outside the guard, and when it is determined that the restriction of the guard has been released in an access area accessible to the operator, the press brake body is brought to an emergency stop. Press brake. 　 The guard comprises an opening which is the access area and a movable door which opens and closes the opening. The restriction of the guard is released when the worker moves the door to open the opening. The press brake according to claim 8. 　 The guard is equipped with a sensor that detects the movement of the door, The control device determines that the restriction on the guard has been released when the movement of the door is detected by the sensor. The press brake according to claim 9. 　 The guard includes a left guard provided on the left side of the press brake body, a right guard provided on the right side of the press brake body, and a rear guard provided behind the press brake body. The aforementioned opening is provided in the rear guard, The press brake according to claim 9. 　 The back gauge further comprises a beam extending in the left-right direction, The stopper is positioned on the beam so as to be slidable in the left-right direction. The press brake according to claim 9. 　 The back gauge further comprises an actuator for moving the beam in the forward and backward direction, The control device is By controlling the actuator, the stopper is moved backward from the opening to a position where the operator can operate the stopper. The press brake according to claim 12. 　 The aforementioned door is configured to slide along the left-right direction. The press brake according to claim 9.

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