JP2001232418A - Method and apparatus for bending - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent work interruption and to reliably secure the safety of a worker when a work obstructs an optical axis in bending work by using an apparatus with an optical axis type safety device integrated thereon. SOLUTION: When a punch 4 and a die 5 (upper/lower dies) are closed by stepping on a foot switch button 11 and a work W is held between the upper/ lower dies 4, 5, the optical axis type safety apparatus which stops a die action when a hand obstructs an optical axis L before die closing is operated, a die action is once stopped simultaneously with die closing in a closing process, and the optical axis type safety apparatus is invalidated. Thereafter, a both-hand operation switch mechanism where bending start switch buttons 10, 10 are pushed with both hands is operated. During a closing process, safety is secured by the optical axis type safety apparatus, and during a bending process, safety is secured by the both-hand operation switch mechanism. Further, during the bending process, the optical axis type safety apparatus is invalidated, and hence such a situation that a work W obstructs the optical axis L to interrupt working does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending method capable of smoothly and safely bending a sheet metal work or the like, and a bending apparatus suitable for carrying out the bending method.

[0002]

2. Description of the Related Art A device called a press brake is used for this type of forming process, that is, for bending a sheet metal work or the like. In this apparatus, an upper table provided with a punch (upper die) and a lower table provided with a die (lower die) are vertically vertically movable and vertically movable, and a sheet metal work is placed on the lower table. The lower table is raised by a hydraulic cylinder or the like to press the work between the die and the punch to perform a predetermined bending process.

[0003] In bending using a press brake or the like, there is a danger that an operator's hand or the like may be interposed between the upper and lower tables and may be pinched between the punch and the die. For this reason,
Conventionally, in this type of bending apparatus, an optical axis type that stops the operation of the upper and lower tables as soon as an operator's hand interrupts the optical axis by installing a light emitter and a light receiver on both sides of the work table. Incorporation of safety devices was being done.

[0004]

This optical axis type safety device has been useful in that it can be installed relatively easily and safety can be ensured. However, depending on the shape of the work, the work itself may be used. However, there is also a problem that the processing work is interrupted by interrupting the light beam (optical axis), so that it does not function as a safety device.

In order to provide an optical axis type safety device capable of effectively functioning for various workpiece shapes, Japanese Patent Application Laid-Open No. 10-328741 discloses a pair of light emitter / receiver using a motor and a screw, respectively. An optical axis type safety device in which the position of the optical axis is movable is disclosed. However, even if the light emitter / receiver can be moved in this way, in a complicated processing step in which the shape or size of the work exceeds expectations or the position or posture of the work is changed in the apparatus, After all, the work blocks the optical axis and does not function as a safety device.

In view of the above, the present invention has been made in view of the problem of the bending apparatus incorporating such an optical axis type safety device, and changes the position and orientation of the work even if the shape and size of the work are special. Even with such a complicated bending process, the work itself does not interrupt the optical axis and the work is not interrupted on the way, and furthermore, the bending method and the bending method which can ensure the safety of the worker reliably. It is intended to provide a processing device.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a bending method for closing a vertical die, sandwiching the work between the upper and lower dies, and thereafter bending the workpiece by further die operation. Until the mold is closed, if the optical axis is interrupted, the mold operation is stopped or the optical axis type safety device with the function of giving a warning is activated, and the mold operation is performed once while clamping the work between the upper and lower molds by closing the mold. It was stopped and the optical safety device was disabled, after which the mold could only be operated by pressing the button with both hands.

Further, as a bending apparatus for suitably performing the above-mentioned processing method, there are provided an upper and lower mold which can be opened and closed, and a function of interrupting the mold operation or interrupting the warning by blocking the optical axis. Equipped with an optical axis type safety device and a two-handed operation switch mechanism, the mold closing operation can be performed only when the optical axis type safety device is in the input state. A folding apparatus was set in which the mold was once stopped, and after the mold was closed, the mold was operated only by pressing a button with both hands by a two-hand operation switch mechanism.

According to the bending method and the bending apparatus of the present invention, since the optical axis type safety device operates during the mold closing process, it is possible to avoid the danger of the hand being caught in the mold and the like. In the bending step, the mold does not operate unless the button is pressed with both hands by the two-hand operation switch mechanism, so that there is no danger of the hand being pinched by the mold. In addition, since the optical axis type safety device is disabled during the bending process, even if the shape and size of the work is special, even if it is a complicated bending process that changes the position and posture of the work Since the work itself does not interrupt the optical axis and the work is not interrupted on the way, the bending can be performed freely.

The "optical axis type safety device" in the bending method and the bending apparatus of the present invention may be designed so as to be automatically invalidated at the same time when the mold is closed. Since the mold operation is temporarily stopped at the time of closing, it may be designed so that it can be invalidated by a human operation such as pressing or releasing a button at this time.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on examples.

The bending apparatus 1 shown in FIG. 1 and FIG.
An upper table 2 having a punch (upper die) 4 at a tip thereof, which is a press brake for bending a sheet metal work.
And a lower table 3 provided with a die (lower die) 5 corresponding to the punch 4 are disposed vertically openably and closably, and are provided with an optical axis type safety device and a two-handed operation switch type safety device (a two-handed operation switch). ) And the operation of the upper and lower tables 2 and 3 can be controlled by a combination of these two safety devices.

The upper table 2 has a punch (upper die) 4 formed in a convex shape at the tip end.
A die (lower die) 5 having two V grooves 5a and 5b corresponding to the punch 4 provided on the table surface is provided. When the foot switch button 11 provided on the floor surface is depressed, the hydraulic cylinder 7 is actuated. When the lower table 3 is raised, the work W is held between the punch 4 and the die 5 when the mold is closed, and when the lower table 3 is further raised, the work W is bent along the groove angle with the V groove 5a (5b) as a bent portion. It is configured to be bent in a V-shape.

As shown in FIGS. 1 and 2, the optical axis type safety device of the present device 1 includes a pair of a light emitter 8 and a light receiver 9 on both left and right sides of the die 5 in front of the V groove 5b. When the optical axis L of the laser beam transmitted from the light emitter 8 to the light receiver 9 is cut off by an operator's hand or the like, the operation of the hydraulic cylinder 7 is immediately stopped, and the mold closing operation of the upper and lower tables 2 and 3 is urgently stopped. It is designed as follows. In this optical axis type safety device, an input state (O
N), the setting is made such that when the upper and lower molds (punch 4 and die 5) close, they are automatically invalidated. That is, the input state is set only during the mold closing operation of the upper and lower tables 2 and 3. Accordingly, even when the work has a complicated shape, the work is large, or a case where a plurality of bending processes are continuously performed, the work W is moved along the optical axis in the bending process after the mold is closed. There is no interruption of the mold operation by interrupting L.

As shown in FIG. 2, each of the light emitter 8 and the light receiver 9 has a predetermined thickness, and is integrally formed on a substrate 12 having pin insertion holes 13 and 13. These substrates 12 are mounted on both sides of the lower table 3, respectively, and pin insertion holes 13, 1
A support base 1 having perforated shaft holes 15 corresponding to 3
6 and 16, the pins 17 are inserted into the pin insertion holes 13 and the shaft holes 15, respectively, and tightened.
It is attached detachably with 2. That is, the light projector 8 and the light receiver 9 of the present apparatus 1 are both detachably attached to the support base 16 and can be easily replaced with a different set of the light projector 8 and the light receiver 9. Therefore, the height of the optical axis L can be freely changed according to the size of the work W or the like by changing the light projector 8 and the light receiver 9 of different sets or changing the thickness of the substrate 12. Further, if the light emitter 8 and the light receiver 9 are in the way, they can be easily removed.

On the other hand, as shown in FIGS. 3A and 3B, the two-hand switch type safety device of the present device 1 has two switches S1 and S2 arranged in series, and each switch S
1, folding start switch button 10, 10 linked with S2
Are arranged on the upper surface of an operation table T installed in front of the lower table 3 at appropriate intervals, and unless both these two folding start switch buttons 10 and 10 are pressed, the drive signal is transmitted to the drive circuit. When the two bending start switch buttons 10 and 10 are both pressed, a drive signal is transmitted to the drive circuit, and the lower table 3 is raised again by the operation of the hydraulic cylinder 7 so that the subsequent bending process can be performed. Designed.

Further, in the present apparatus 1, as shown in FIG.
Only when the sensor is OK, that is, when the optical axis type safety device is ON, the lower table 3 is set so as to move up and open and close the mold. Immediately before the contact with the workpiece, the ascending speed of the lower table 3 once decreases, and when the mold is closed, that is, when the die 5 contacts the workpiece W, the sensor operates and the operation of the hydraulic cylinder 7 temporarily stops. Is set to be invalid (OFF).

Hereinafter, an example of an operation process of bending the work W into a V-shape using the bending apparatus 1 will be described.

First, the worker places the work W at a predetermined position on the die 5 by hand, and depresses the foot switch button 11 while holding the work W so as not to shift from the predetermined position. When the foot switch button 11 is depressed, the optical axis type safety device enters the input state, and the hydraulic cylinder 7 operates to start lowering the lower table 3. During the upward movement of the lower table 3, the operation of the hydraulic cylinder 7 is immediately stopped when the optical axis L between the light emitter 8 and the light receiver 9 is interrupted by the hand of an operator or the like.

The lower table 3 lowers the ascending speed immediately before the mold is closed, and when the mold is closed, that is, when the punch 4 comes into contact with the work W and clamps the work W, the sensor operates and the operation of the hydraulic cylinder 7 is automatically stopped. At the same time, the optical axis type safety device becomes invalid (OFF). Therefore, in the subsequent steps, the operation of the apparatus 1 is not stopped by the work W blocking the optical axis L until the foot switch button 11 is depressed again.

Here, the work W is held between the punch 4 and the die 5, and the worker can retreat his hand.
Next, the operator operates the folding start switch buttons 10 and 1 with both hands.
0 at the same time, the lower table 3 is further raised, the work W is strongly closed by the punch 4 and the die 5, and the work W is V-shaped along the groove angle with the V groove 5a (5b) as a bent portion. Can be folded. When the bending is completed, the lower table 3 is automatically lowered (pulled back) to open the mold. Therefore, if the operator takes out the work W from the apparatus 1 or continuously bends the work W, The above process may be repeated by pressing the foot switch button 11 again with the work W in a predetermined posture and position.

In the bending apparatus and the bending method of the present invention, the optical axis type safety device enters an input state (ON) when the foot switch button 11 is depressed, and becomes invalid (OFF) when the depression is released. ) Can be designed. Further, the pair of light emitters 8 and light receivers 9 can be moved back and forth, and the optical axis can be moved to a non-blocking position according to the shape of the workpiece, and the light emitters 8 and light receivers 9 can be automatically or manually operated, respectively. It can be designed to be rotatable and rotated appropriately according to the shape of the workpiece so as not to hinder the processing. Furthermore, in the device 1, the operation of the hydraulic cylinder 7 is designed to be stopped when the optical axis L is shut off. However, instead of stopping the operation or stopping the operation, an alarm sounds, a warning lamp It can also be designed to warn the operator, such as blinking.

The two-handed switch type safety device of the above-mentioned device 1 is an example for one-person operation. However, two sets of folding start switch buttons 10.10, four in total, are operated by two people. Can also be configured for

The above device 1 is an example in which an optical axis type safety device and a two-hand switch type safety device are incorporated in a so-called 2V die in which two V grooves are provided in the die.
The present invention can also be configured by incorporating an optical axis type safety device and a two-handed switch type safety device into a bending device having another configuration, for example, a 1V die or a hemming die for bending a work by 180 degrees. In this case, the hemming die may be provided with an optical axis type safety device at each of the primary bent portion and the secondary bent portion.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a configuration of a bending device according to one embodiment of the present invention.

FIG. 2 is a schematic front view showing a configuration of an optical axis type safety device in the bending device of FIG.

3A and 3B are diagrams showing a configuration example of a two-hand switch type safety device, wherein FIG. 3A is a circuit diagram thereof, and FIG. 3B is a perspective view showing an arrangement state and an operation state of a folding start switch button. .

4 is a work process diagram showing an example of a bending process using the bending device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bending apparatus 2 Upper table 3 Lower table 4 Punch (upper type) 5 Die (lower type) 5a, 5b V groove 7 Hydraulic cylinder 8 Projector 9 Receiver 10 Folding start switch button 11 Foot switch button

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Yamada 2480 Mado, Hiratsuka-shi, Kanagawa F-term in the Hiratsuka Plant of Mitsubishi Plastics Corporation (reference) 4E063 AA01 BA07 FA06 FA10 4E088 BA02 KK04 KK08

Claims (2)

[Claims] 1. A bending method for closing a top and bottom mold, sandwiching a work between the top and bottom dies, and thereafter bending the work by a further molding operation. Activate the optical axis type safety device with the function of stopping or warning, clamping the work between the upper and lower molds by closing the mold and stopping the mold operation at the same time, invalidating the optical axis type safety device, and thereafter A bending method wherein the mold can be operated only by pressing a button with both hands. 2. An upper and lower mold provided to be openable and closable, an optical axis type safety device having a function of interrupting or warning the mold operation by blocking an optical axis, and a two-hand operation switch mechanism, The mold closing operation is enabled only when the optical axis type safety device is in the input state, and the mold operation is temporarily stopped by holding the work between the upper and lower molds by closing the mold, and after closing the mold, the two-hand operation switch mechanism is used with both hands. A bending machine set so that the mold can be operated only by pressing a button.