JP2001259744A - Safety apparatus of press brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a malfunction in press working, to easily adjust an optical axis and to easily retreat an optical sensor. SOLUTION: In a safety apparatus of a press brake which stops a press action when an optical axis of an optical sensor 5 is interrupted with approach of an upper die 1 and lower die 2 when the gap between the upper die 1 and the lower die 2 is measured and reach a size so that a finger can be put therein, the detection of the optical sensor 5 is stopped. the malfunction, in which the optical axis is interrupted with the object to be worked, etc., to stop an press action, is eliminated, at this stage, a finger cannot enter between the upper die 1 and the lower die 2, thus, safety is secured. Further, the optical sensor 5 is mounted to a sensor mounting plate 6 narrowing downward, the sensor mounting plate 6 is inserted into an inserting groove narrowing downward of a support table 7 arranged to a lower die 1 side as freely inserting in/out, the sensor mounting plate 6 is easily mounted/demounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press brake safety device using an optical sensor.

[0002]

2. Description of the Related Art Conventionally, a press brake for bending a thin plate has been used to perform a press operation when an upper axis and a lower mold are brought close to each other and an optical axis is interrupted by an operator's finger or the like. An optical sensor-type safety device for stopping is provided.

[0003] As one example, Japanese Patent Publication No. 7-45118 discloses that not only the press operation is stopped by blocking the optical axis as described above, but also the lowering of the upper die by two optical sensors arranged vertically. In the figure, a speed is detected, and when the speed is higher than a predetermined speed, the pressing operation is stopped.

Japanese Patent Laid-Open Publication No. Hei 5-277564 discloses an optical sensor in which the mounting portion of the optical sensor is finely moved by a hinge or a long hole to adjust the optical axis, and is fixed at a fixed position by clamping with a clamp. I have.

[0005]

However, in the above-described safety device of the optical sensor type, since the light shielding is detected until the press, even when the workpiece interrupts the optical axis during the processing, etc. The emergency stop of the press brake may occur. In such a case, there is a danger that the operator may be confused and an accident may occur at the time of the recovery work.

Further, it is troublesome to adjust the positions of the light emitter and the light receiver of the optical sensor according to the shape of the lower mold and the workpiece, and to retract the optical sensor when replacing the mold. There is also a problem that this is the case.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a safety device for a press brake in which there is no possibility of malfunction, the optical axis can be easily adjusted, and the optical sensor can be easily retracted.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a press brake safety device for stopping a press operation when an optical axis of an optical sensor is interrupted when an upper mold and a lower mold approach each other. The distance between the upper mold and the lower mold is measured, and when the distance becomes too small for the finger to enter, the detection by the optical sensor is stopped.

In this safety device, a malfunction in which the optical axis is shielded from light by a workpiece or the like at the time of pressing and the pressing operation is stopped is eliminated. At this stage, a finger does not enter between the upper die and the lower die. Nature is also secured.

Further, the optical sensor is mounted on a sensor mounting plate having a lower constriction, and the sensor mounting plate is removably inserted into an insertion groove of the lower constriction provided on the lower die. Accordingly, the optical sensor can be easily fixed at an accurate position, and the sensor mounting plate can be easily attached and detached when the mold is replaced.

Further, the height of the optical axis may be adjusted by forming the insertion groove in the support base in a plurality of steps with a difference in height, and inserting a sensor mounting plate into an appropriate step.

[0012] Further, a holding frame which moves up and down with the rotation of the screw shaft is provided on the support base, the insertion groove is formed in the holding frame, and the holding shaft is rotated by rotating the screw shaft to raise and lower the optical axis. May be adjusted.

If a hook hooking hole is formed in the sensor mounting plate, a sensor mounting plate for replacement or a sensor mounting plate detached from the support base at the time of mold replacement can be hooked on the hook.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, as shown in FIG. 1, an upper die 1 and a lower die 2 are mounted on an upper table 3 and a lower table 4, respectively, and the lower table 4 is raised to perform press working. The safety device for the press brake will be described.

In this press brake, an optical sensor 5 including a light emitter and a light receiver is arranged on both sides of the lower die 2.
The optical sensor 5 is mounted on a sensor mounting plate 6, and the sensor mounting plate 6 is held on a support 7 fixed to the lower table 4. As the optical sensor 5, a laser type is used, and its optical axis 8 passes through the front of the upper die 1 above the thin plate P which is a workpiece as shown in FIG. 2. .

Also, as shown in FIG.
A proximity switch 10 is provided on one side via a bracket 9. The proximity switch 10 measures the distance between the upper die 1 and the lower die 2, and when the distance becomes too small for a finger to enter, the light of the optical sensor 5 is stopped by the signal of the proximity switch 10 and the light is blocked. Is stopped. Although a switch using a magnetic field is used here as the proximity switch 10, a limit switch or the like may be used.

In such a safety device, there is no erroneous operation in which the optical axis is shielded from light by the workpiece or the like and the pressing operation is stopped, and a finger enters between the upper die 1 and the lower die 2 at this stage. No security is ensured.

Next, a first embodiment of the mounting portion of the optical sensor 5 will be described with reference to FIGS.

In this example, as shown in FIG. 3, the lower part of the sensor mounting plate 6 is formed with a taper of constriction, and
Is formed with an insertion groove 11 of a lower constriction corresponding to the taper of the sensor mounting plate 6. A sensor mounting hole 12 and a hook hooking hole 13 are provided in an upper portion of the sensor mounting plate 6, and screw holes 14 are formed on both sides of the insertion groove 11 of the support base 7. A hook 15 is attached to an end surface of the lower table 4.

Then, as shown in FIGS. 4 and 5, the optical sensor 5 is inserted and fixed in the sensor mounting hole 12 of the sensor mounting plate 6, and the sensor mounting plate 6 is inserted into the insertion groove 11 of the support base 7. Insert the fixing cover 16 into the insertion groove 1 in this state.
1, and a bolt 17 is screwed into the screw hole 14 to fix the fixing cover 16.
By tightening, the optical sensor 5 is attached.

According to this mounting mode, if the thumbscrews 18 are loosened and the sensor mounting plate 6 is pulled out from the insertion groove 11 of the support base 7, the sensor mounting plate 6 does not hinder the mold changing operation, and the press working is performed. At this time, when the sensor mounting plate 6 is inserted into the insertion groove 11, they are fitted in the shape of a downward constriction, so that the optical sensor 5 can be easily fixed at a predetermined position and the optical axis can be stabilized. Can be.

For example, as shown in FIG. 6, in order to set the height of the optical axis higher by a, a sensor mounting plate 6 on which the optical sensor 5 is mounted at such a position is separately prepared.
It may be replaced as needed. At this time, the unnecessary sensor mounting plate 6 may be hooked on the hook 15 using the hook hooking hole 13.

Next, a second embodiment of the mounting portion of the optical sensor 5 will be described with reference to FIGS. 7 to 10, focusing on differences from the first embodiment.

In this example, as shown in FIG.
In the case where the insertion groove 11 is formed in two steps with a difference in height and the optical axis may be low, as shown in FIGS. 8, 9 and 10A, the lower insertion groove 11 If it is necessary to insert the sensor mounting plate 6 into the
As shown in FIG. 10B, the height of the optical axis is adjusted by inserting the sensor mounting plate 6 into the upper insertion groove 11.

Next, a third embodiment of the mounting portion of the optical sensor 5 will be described with reference to FIGS. 11 to 14, focusing on differences from the first embodiment.

In this example, as shown in FIGS. 11 to 13, the insertion groove 11 is formed in the holding frame 19 provided on the support base 7, and the arm 20 of the holding frame 19 is inserted through the support base 7. The holding frame 19 moves up and down with the rotation of the screw shaft 21.

Then, as shown in FIG. 14 (a), the optical axis is shifted from the state where the optical axis is low, as shown in FIG.
If the screw shaft 21 is set higher,
2, a handle (not shown) is engaged, and the screw shaft 21 is rotated to raise the holding frame 19. The height of the optical axis can be adjusted steplessly.

In these mounting modes, the optical sensor 5
Can be adjusted only in the height direction, but since the molding position of the press brake does not move in the front-rear direction, there is no need for a mechanism for adjusting the optical axis in the front-rear direction.

[0029]

As described above, in the safety device according to the present invention, the detection by the optical sensor is stopped when the upper mold and the lower mold approach each other up to a predetermined distance. As a result, there is no erroneous operation in which the press operation is interrupted due to shading, and no finger enters between the upper mold and the lower mold at this stage, so that safety is also ensured.

Further, since the sensor mounting plate and the support table are fitted in the shape of a constriction, the optical sensor can be easily fixed at a predetermined position to stabilize the optical axis, and the mold can be formed. At the time of replacement, the sensor mounting plate can be easily attached and detached.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a safety device for a press brake according to the present invention.

FIG. 2 is a side view showing the position of the optical axis in the above.

FIG. 3 is an exploded perspective view of a first mounting mode of the optical sensor.

FIG. 4 is a perspective view showing an attached state of the above.

FIG. 5 is a longitudinal sectional side view of the above.

FIG. 6 is a schematic front view showing the setting of the height of the optical axis in the above.

FIG. 7 is an exploded perspective view of a second mounting mode of the optical sensor.

FIG. 8 is a perspective view showing an attached state of the above.

FIG. 9 is a longitudinal sectional side view of the above.

FIG. 10 is a schematic front view showing the setting of the height of the optical axis in the above.

FIG. 11 is an exploded perspective view of a third mounting mode of the optical sensor.

FIG. 12 is a perspective view showing an attached state of the above.

FIG. 13 is a cross-sectional plan view of the above.

FIG. 14 is a schematic front view showing the setting of the height of the optical axis in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper die 2 Lower die 3 Upper table 4 Lower table 5 Optical sensor 6 Sensor mounting plate 7 Support base 8 Optical axis 9 Bracket 10 Proximity switch 11 Insertion groove 12 Sensor mounting hole 13 Hook hook hole 15 Hook 16 Fixed cover 17 Bolt 18 Thumbscrew 19 Screw shaft 20 Holding frame

Claims (5)

[Claims] When the optical axis of an optical sensor is interrupted when the upper mold and the lower mold approach each other, a press brake safety device that stops the press operation measures the distance between the upper mold and the lower mold,
A safety device for a press brake, wherein the detection by the optical sensor is stopped when the interval becomes too small for a finger to enter. 2. The optical sensor according to claim 1, wherein said optical sensor is mounted on a lower-mounting sensor mounting plate, and said sensor mounting plate is removably inserted into a lower-mounting insertion groove of a supporter provided on said lower mold side. The safety device for a press brake according to claim 1, wherein: 3. The safety device for a press brake according to claim 2, wherein the insertion groove is formed in a plurality of steps on the support base with a difference in height. 4. The safety device for a press brake according to claim 2, wherein a holding frame that moves up and down with rotation of a screw shaft is provided on the support base, and the insertion groove is formed in the holding frame. 5. The safety device for a press brake according to claim 2, wherein a hook catching hole is formed in the sensor mounting plate.