JP2001259898A - Safety distance operating method in press, and safety device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety distance operating method excellent in startability, and a safety device in a press. SOLUTION: The safety distance operating method to show the distance between the arrangement position of an invasion detector which outputs the invasion signal when foreign matters invade in a working area of the press and a front side of a die comprises a step of measuring the time from the time when the stop signal is outputted to the press to the time when a slide is stopped as a sudden stop time, a step of operating the safety distance based on the measured sudden stop time, and a step of successively updating the previously operated safety distance to the present safety distance in every operation, and a controller of operating these steps is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for calculating a safe distance in a press machine.

[0002]

2. Description of the Related Art In order to prevent an accident when a foreign object such as a worker's hand enters the work area of a slide during operation of a press machine, a light beam type safety is provided at an entrance to the work area of the slide from outside. Equipment is installed. FIG. 5 is a perspective view showing an example of a press machine provided with such a light beam type safety device. A bolster 2 is provided at a lower portion of the press machine 1, and a lower mold 3 is provided on an upper surface of the bolster 2. A slide 4 is provided at the upper part of the press machine 1 and at a position facing the bolster 2 so as to be movable up and down. An upper mold 5 is arranged on the lower surface of the slide 4 so as to face the lower mold 3. ing. The work area 6 in which the slide 4 moves up and down is defined as a danger area, and the work area 6 excluding the work surface on which the worker works (usually the front surface of the press machine 1) cannot enter from outside. Is surrounded by a guard or the like. A light beam safety device 7 is disposed on the left and right of the entrance of the work surface, and the light beam safety device 7 includes a light projector 7a and a light receiver 7b facing each other.

As shown in FIG. 6, a light beam emitted from a light projector 7a is received by a light receiver 7b, and a light beam curtain is formed at the entrance of the work surface. The intruder (foreign matter such as a worker's hand) shields the press machine 1 shown in FIG. Then, when the controller (not shown) receives the detection signal of the light beam type safety device 7, if the slide 4 is operating, the slide 4 is emergency-stopped to prevent an accident.

[0004]

However, the conventional emergency stop method using the light beam type safety device 7 has the following problems. That is, as shown in FIG. 7, the light beam type safety device 7 is installed at a safe distance A which is a predetermined distance from an end surface of the lower die 3 or the upper die 5 near the front surface of the press machine 1. The safety distance A is usually a value calculated by multiplying the maximum speed (1.6 m / sec) when a human hand is operated and the sudden stop time from when the stop signal is output to when the slide 4 stops. It is. At the time of an emergency stop, the brake is applied after the clutch of the slide drive unit is disengaged, and the slide 4 stops, but the sudden stop time gradually increases in accordance with an increase in the amount of wear on the brake pad accompanying an increase in the press operation time. Therefore, normally, the value calculated based on the sudden stop time after the predetermined operation time when the brake pad is worn is set in the controller as the safety distance A. However, this causes a problem that the safety distance A, which is always too large, is set until the predetermined operation time is reached, so that the worker does not lean on the press machine 1 and thus the workability is poor. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method and an apparatus for calculating a safe distance in a press machine capable of securing a leaning suitable for a sudden stop time. .

[0006]

In order to achieve the above object, the present invention provides an intrusion detector for outputting an intrusion signal when a foreign object enters a working area of a press machine. A step of measuring a time from when a stop signal is output to the press machine to when the slide stops as a sudden stop time in the method of calculating a safe distance indicating a distance between the press and the front of the mold; The method includes a step of calculating a safety distance based on time, and a step of sequentially updating the previously calculated safety distance to a current safety distance each time the calculation is performed. Further, the controller has a controller that operates based on the above steps.

According to the present invention, the controller outputs a stop signal to the solenoid valve that controls the clutch and brake when a measurement signal from a measurement indicator such as a measurement button or an intrusion signal from an intrusion detector is input. . Then, based on the output stop signal and the vertical speed of the slide, the time from when the stop signal is output to the clutch and brake of the press machine to when the slide stops is measured as the sudden stop time. The product of the measured sudden stop time and a predetermined speed of the human hand stored in advance is defined as a safe distance. Then, every time the calculation is performed, the current safety distance is replaced with the previously calculated safety distance. A controller that operates such a process can always set a necessary and sufficient safety distance at the present time in consideration of the amount of wear of the clutch and brake, so that a press machine with good working efficiency and excellent leaning can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to FIGS. Figures 1, 2, 3, 4
In FIG. 5, the same elements as those described in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof is omitted. FIG. 1 shows a configuration of an embodiment according to the present invention. An output shaft of an electric motor 8 which is a driving source of the press machine 1 is connected to a flywheel 10 for smoothing the operation of the press machine 1 via a speed reducer 9. The output shaft of the flywheel 10 is connected to a first gear 12 via a clutch & brake 11. When transmitting the output rotation of the flywheel 10 to the first gear 12, the clutch of the clutch & brake 11 is engaged and the brake is not operated. Also, the first gear 1
When stopping the rotation of 2, the clutch of the clutch & brake 11 is disengaged to apply the brake. The first gear 12 meshes with a second gear 13 having more teeth than the first gear 12, and the output shaft of the second gear 13 is connected to the crank mechanism 1.
4 are provided. The slide 4 is attached to an output portion of the crank mechanism 14 that converts the rotational movement of the second gear 13 into a slide movement, and the upper mold 5 is attached to the lower surface of the slide 4. On the other hand, a lower mold 3 is attached to the upper surface of the bolster 2 at a position facing the upper mold 5.

A light beam type safety device 7 as an intrusion detector for detecting that a human hand or the like has entered the work area is provided movably in the front-rear direction. The press machine 1 is positioned at a safe distance A from an end face near the front face of the press machine 1 via a gear 23 and a rack 24 by a servomotor 22. When a human hand or the like enters the work area at the safety distance A, the light beam type safety device 7 outputs an intrusion signal W of the ON signal “1”, and when not intruding, the intrusion signal W of the OFF signal “0”. Is output. As another detector, a speed detector 15 for detecting the vertical speed of the slide 4 is attached near the slide 4.

The controller 17 receives a slide speed Hd from the speed detector 15 and an intrusion signal W from the light beam type safety device 7. The controller 17 outputs a servo motor command M to the servo motor 22 such that the light beam type safety device 7 approaches the target position. Further, the controller 17 outputs a solenoid valve command D to the solenoid valve 16 that controls the engagement / disengagement of the clutch of the clutch & brake 11 and the operation of the brake. When the solenoid valve command D is the ON signal “1”, the solenoid valve 16 outputs a predetermined value of the fluid pressure Ph. Due to this fluid pressure Ph, the clutch of the clutch & brake 11 is engaged and the brake is not operated, so that the rotation of the flywheel 10 is transmitted to the first gear 12. On the other hand, when the solenoid valve command D is the off signal “0”, the fluid pressure Ph becomes zero, the engagement of the clutch of the clutch & brake 11 is released, and the rotation of the flywheel 10 is not transmitted to the first gear 12. Then, the brake is operated and the rotation of the first gear 12 is braked by the brake.

The panel of the controller 17 is provided with a measurement button 18, a display 19, a first warning lamp 20, and a second warning lamp 21. The measurement button 18 is
Turn on when updating the safety distance A. Measurement button 18
When the switch is turned on, the solenoid valve command D of the off signal “0” is output, and when the switch is turned off, the solenoid valve command D of the on signal “1” is output. The display 19 displays the updated safety distance A. When a predetermined operating time of the press machine 1 has passed and it is time to update the safety distance A, the first warning lamp 20
Flashes to prompt the worker to update the safety distance A.
Further, when the updated safety distance A becomes larger than a safety distance threshold value Aj obtained by a method described later, the second warning lamp 21 flashes and the worker receives the clutch & brake 11.
To report abnormalities.

Next, the processing operation of the controller 17 will be described with reference to the flowchart of FIG. In the control flow in FIG. 2, each processing step is indicated by a number with S added. In S1, it is determined whether or not the measurement time of the safety distance A has come after a predetermined operation time has elapsed. When the measurement time has come, the first warning lamp 20 flashes in S2 and the process proceeds to S3. . If the measurement time has not been reached, the process proceeds to S11. When updating the safety distance A, the operator turns on the measurement button 18 while the slide 4 is being driven. In S3, it is determined whether or not the measurement button 18 is turned on,
At the time of the ON operation, the solenoid valve command D of the OFF signal “0” is given at S4, and at the time of the OFF operation, the ON signal “1” is given at S5.
Is output to the electromagnetic valve 16 and the process proceeds to S6.

At S6, the slide speed Hd of the slide 4
Is determined to be a zero value, and if the value is zero, the process proceeds to S7, and if not, the process of S6 is continued.
In S7, the time from when the electromagnetic valve command D is set to the OFF signal “0” to when the slide 4 stops is defined as the sudden stop time Tt. Then, the safe distance At is calculated by multiplying the sudden stop time Tt by 1.6 m / sec, and the process proceeds to S8. S
At 8, it is determined whether or not the current safety distance At is greater than the safety distance threshold value Aj. If the current safety distance At is greater, the second warning lamp 21 flashes at S9 to complete the control. Safety distance threshold A
If j is equal to or less than j, a servo motor command M is output to the servo motor 22 so that the safe distance A is set to the calculated current safe distance At in S10, and the control is completed. On the other hand, S
At 11, it is determined whether or not the intrusion signal W is the ON signal "1". When the intrusion signal W is the ON signal "1", the solenoid valve command D of the OFF signal "0" is output to the solenoid valve 16 at S12. Move on to processing. When the intrusion signal W is the off signal “0”, S
The processing of step 11 is continued.

Next, the operation and effect of this embodiment will be described. When it is time to measure the safety distance A and the first warning lamp 20 flashes, when the slide 4 comes to a stroke of approximately 90 degrees, the worker turns on the measurement button 18 (S1,
2, 3). The strokes of 0 ° and 180 ° indicate the top dead center position and the bottom dead center position of the slide 4, and when the stroke is approximately 90 °, the descending speed of the slide 4 is the highest. When the operator turns on the measurement button 18, the solenoid valve command D of the off signal “0” is output to the solenoid valve 16 (S
4) Since the engaged clutch is released and the brake is operated, the rotation of the first gear 12 is rapidly reduced.
When the operator turns on the measurement button 18, the measurement may be automatically started at the 90-degree position. FIG.
As shown in FIG. 3A, assuming that the solenoid valve command D outputs an off signal “0” from time t = 0, FIG.
The response time Tv which is the response time of the solenoid valve 16 as shown in FIG.
Later, the clutch is disengaged and the brake is activated. The slide speed Hd is determined by the deceleration time T after the brake starts to operate.
It will be zero after s. That is, the slide 4 stops after a sudden stop time Tt obtained by adding the response time Tv and the deceleration time Ts after the output of the solenoid valve command D of the OFF signal “0”. The present safety distance At is calculated based on the sudden stop time Tt (S6, 7). When the calculated current safety distance At is larger than the safety distance threshold Aj, the amount of wear of the clutch & brake 11 is large, so that When it is determined that the stop time Tt has increased, the second warning lamp 21 blinks to prompt maintenance of the clutch & brake 11 (S9).

In FIG. 4, the vertical axis represents the safety distance A, the horizontal axis represents the operating time Tp of the press machine 1, and the solid line represents the measurement time interval Ti.
, The dotted line indicates a constant value of the conventional safe distance Ac according to the conventional method. Measurement time interval T
i is a predetermined interval set in advance, for example, one month. The next safety distance threshold Aj is estimated based on the previous safety distance At and the current safety distance At measured this time. When the safety distance A measured next time is larger than the estimated safety distance threshold Aj, the wear speed of the clutch & brake 11 is determined. Is abnormally large, and the second warning lamp 21 blinks. In FIG. 4, the operating time Tp is the overhaul time T
e, the clutch & brake 11 is regularly maintained or replaced. The current safety distance At is equal to the safety distance threshold Aj
In the following cases, the light beam type safety device 7 is positioned at the position of the obtained current safety distance At (S10). On the other hand, if it is determined in S1 that the measurement time has not come, the intrusion signal W
Is determined to be an ON signal “1”. When the intrusion signal W is the ON signal "1", it is determined that a human hand or the like has entered the work area (S11), and the electromagnetic valve command D of the OFF signal "0" is sent to the electromagnetic valve 16 to stop the machine. Output (S1
2) The press machine 1 is stopped.

As described above, the sudden stop time Tt is measured at every predetermined measurement time interval Ti, and the current safe distance At is obtained. Then, the safety distance A at the position where the light beam type safety device 7 is positioned is updated at every measurement time interval according to the wear amount of the clutch & brake 11. With this, clutch &
Since the necessary and sufficient safety distance A can always be set in consideration of the wear amount of the brake 11, the leaning of the operator to the press machine 1 is improved, so that excellent work efficiency can be obtained. Further, the intrusion signal W is always determined even when the measurement time has not come. When the intrusion signal W is the ON signal "1", it is determined that a human hand or the like has entered the work area, and the press machine 1 is stopped. At the same time, the safety distance A is measured. Thereby, the position of the light beam type safety device 7 can be updated with the safety distance A which is constantly updated, so that a safety device with good approach can be obtained. Furthermore, since the safety distance threshold Aj is estimated based on the measured current safety distance At and the abnormality of the clutch & brake 11 is detected, a machine failure can be predicted and maintenance time can be shortened, so that work efficiency is improved.

In the present embodiment, the safety distance A is obtained by measuring the sudden stop time Tt by turning on the measuring button 18 by the operator, but the light beam of the light beam type safety device 7 is In this case, a measurement signal may be output by intentionally shading light to measure the sudden stop time Tt. In the present embodiment, when the measurement time of the safety distance A comes, the first warning lamp 20 flashes to urge the worker to turn on the measurement button 18 to measure the safety distance A. When the time comes, the solenoid valve command D of the OFF signal “0” may be automatically output to the solenoid valve 16 when the slide 4 reaches the 90-degree stroke, and measurement may be performed. Further, even if the first warning lamp 20 does not blink, the worker may turn on the measurement button 18 at any time to measure the safe distance A. In the present embodiment, the light beam type safety device 7 is moved to the position of the calculated safety distance A by the servo motor 2.
2, the worker looks at the required safety distance A displayed on the display, and the worker manually operates the beam-type safety device 7 in a state where the worker supervises the key with the key. May be positioned. Furthermore, in the present embodiment, the speed detector 15 is used to detect the slide speed Hd, but the position is detected by the position detector,
The speed may be calculated by differentiating the detected position. Alternatively, the slide speed may be calculated based on the rotation speed of the electric motor 8.

As described above, according to the present invention, when the measurement signal from the measurement indicator such as the measurement button or the intrusion signal from the intrusion detector is input, the stop signal for stopping the slide to the solenoid valve for controlling the clutch & brake is inputted. Is output. Then, the time from when the stop signal is output to when the slide stops is measured as the sudden stop time. The product of the measured sudden stop time and the predetermined speed of the human hand stored in advance is determined as the safety distance. Each time the safety distance is obtained, the current safety distance is replaced with the safety distance calculated previously. As a result, the necessary and sufficient safety distance at the present time can always be set in consideration of the amount of wear of the clutch and brake, so that a press machine with good working efficiency and good leaning can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of the present embodiment.

FIG. 2 is an example of a control flowchart according to the embodiment.

FIG. 3 is an explanatory diagram of a temporal change in a solenoid valve command and a slide speed.

FIG. 4 is an explanatory diagram of a change in a safe distance with respect to an operation time of a press machine.

FIG. 5 is a perspective view of a press machine provided with a light beam type safety device.

FIG. 6 is an explanatory view of a light beam curtain of the light beam type safety device.

FIG. 7 is an explanatory diagram of a safe distance.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Press machine, 2 bolster, 3 ... Lower mold, 4 ... Slide, 5 ... Upper mold, 6 ... Work area, 7 ... Light beam type safety device,
7a: light emitter, 7b: light receiver, 8: electric motor, 9: speed reducer, 10: flywheel, 11: clutch & brake, 12: first gear, 13: second gear, 14: crank mechanism, 15: speed Detector, 16 ... solenoid valve, 17 ... controller, 18 ... measurement button, 19 ... display, 20 ... first warning lamp, 21 ... second warning lamp, 22 ... servo motor,
23: gear, 24: rack, A: safe distance, Aj: safe distance threshold, D: solenoid valve command, Hd: slide speed, M:
Servo motor command, Tv: response time, Tp: operating time,
Ts: deceleration time, Tt: sudden stop time, Ti: measurement time interval, At: current safe distance.

Claims (2)

[Claims] In a method for calculating a safety distance indicating a distance between an arrangement position of an intrusion detector for outputting an intrusion signal when a foreign object enters a work area of a press machine and a front surface of a mold, the press machine is stopped. Measuring the time from when the signal is output to when the slide stops as a sudden stop time, calculating the safety distance based on the measured sudden stop time, and calculating the safety distance each time the calculation is performed. And a step of sequentially updating the distance to the current safe distance. 2. An intrusion detector which is disposed at a safe distance from the mold to the front of the press machine and outputs an intrusion signal when a foreign object enters the work area; In a safety device for a press machine having a controller for outputting a stop signal for suddenly stopping a slide to be moved up and down, a speed detector for detecting a vertical speed of the slide is provided, and the controller starts the slide from the time when the slide stop signal is output. Is measured as the sudden stop time, the safety distance is calculated based on the measured sudden stop time, and each time the safety distance is calculated, the previously calculated safety distance is sequentially updated to the current safe distance. A safety device for press machines.