JP2001227696A - Antireflection mechanism for light ray type safety device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection mechanism for a photoelectronic safety device for preventing the reflection of the light emitted from a light-emitting device, having a length of a guide plate as a safety distance, and capable of preventing the reflection of the light to provide a comfortable working condition. SOLUTION: This antireflection mechanism 22 has a constitution to surely detect the light-shielding of plural optical axes formed by the light-emitting device and a light-intercepting device, and is mounted on a central part of a guard plate 19 mounted at lower parts of plural optical axes for preventing the light emitted from the light-emitting device from being reflected by the guard plate 19, and surely detecting the light-shielding of the optical axes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam type safety device employing a press machine or the like, and more particularly to an antireflection mechanism of a light beam type safety device for preventing reflection of light emitted from a light emitting element.

[0002]

2. Description of the Related Art Conventionally, in a press machine or the like, a light beam type safety device has been installed between a machine and an operator to ensure the safety of work. For example, FIG. 7 shows a system used in a conventional light beam type safety device, in which a light emitting section 1 in which a plurality of light emitting elements 1-1 to 1-n are disposed, and a plurality of light receiving elements 2-1 to 2- n
Are arranged facing each other, an optical axis is created between the corresponding light emitting element and the light receiving element, and the drive of the press machine is stopped depending on whether the optical axis is interrupted or not. For example,
When any one of the optical axes is interrupted in the process of lowering the slide of the press machine, the press machine is stopped immediately.

It is to be noted that not only a press machine but also a device for installing a light beam type safety device between a device and an operator to ensure work safety has the same configuration.

[0004]

The above-mentioned conventional system has the following problems. That is, the presence of the guard plate 3 located below the light emitting unit 1 and the light receiving unit 2 is present. Essentially, the guard plate 3 prevents the worker's body from entering the press machine from below the light beam type safety device. Therefore, as shown in FIG. 8, the guard plate 3 is formed with a length of the safety distance L to completely close the lower portion between the optical axis 4 and the press machine 5. FIG. 8 is a side view as seen from the direction of arrow a in FIG.

However, in this case, as shown by a dashed line in FIG. 7, light emitted from the lower light-emitting elements 1-n and the like is reflected at the central portion of the guard plate 3 and is directed to the opposing light-receiving elements 2-n and the like. input. Therefore, even when a part of the body blocks the original optical axis (indicated by an X in FIG. 7), it cannot be determined that the light is blocked, and for example, the drive of the press machine 5 cannot be stopped.

This can be said also above the optical axis 4 in FIG. For this reason, in the conventional light beam type safety device, the guard plate 3 is disposed further away from the safety distance L by d as shown in FIG. In this case, a gap is formed by the distance d, which causes a problem in safety, and furthermore, the distance between the operator and the press machine is increased, thereby deteriorating workability.

In order to solve the above-mentioned problems, the present invention provides an anti-reflection mechanism of a light beam type safety device which has a safety distance L where the length of the guard plate 3 is set, prevents light reflection, and has excellent workability. is there.

[0008]

According to the first aspect of the present invention, there is provided a light emitting unit having a plurality of light emitting elements, and an equal number of light receiving elements provided facing the light emitting elements. In a light beam type safety device having a light receiving portion provided and a guard plate located below a plurality of optical axes formed between the light emitting element and the light receiving element, an antireflection mechanism is provided at substantially the center of the guard plate. This can be achieved by providing an anti-reflection mechanism for the formed light beam safety device.

Here, a device in which the above-described light beam safety device is used is, for example, a press machine or the like, and the light beam safety device is disposed between the press machine or the like and an operator. Various anti-reflection mechanisms are conceivable. For example, formation of unevenness, application of a non-reflective paint, attachment of a non-reflective member, and the like can be considered.

With this configuration, the light emitted from the light emitting element is not reflected by the guard plate and enters the light receiving element, so that the interruption of the optical axis can be reliably detected. The safety of the device can be increased.

According to a second aspect of the present invention, in the first aspect of the invention, an upper guard plate is also provided above the plurality of optical axes, and for example, an anti-reflection mechanism is formed substantially at the center of the upper guard plate. ing.

With this configuration, it is possible to prevent reflection of light even above the light beam type safety device, to reliably detect interruption of the optical axis, and to enhance the safety of the light beam type safety device. it can.

According to a third aspect of the present invention, in the first aspect of the invention, the anti-reflection mechanism is, for example, unevenness formed on the guard plate. With this configuration,
Light reflection can be prevented, and interruption of the optical axis can be reliably prevented. In addition, it is relatively easy to provide the guard plate with irregularities. For example, it can be easily formed by creating a corresponding mold.

According to a fourth aspect of the present invention, in the second aspect of the invention, the anti-reflection mechanism is, for example, unevenness formed on the guard plate. This embodiment corresponds to claim 2 described above, and this configuration can also prevent reflection of upward light and reliably prevent interruption of the optical axis. Also, it is relatively easy to form irregularities on the guard plate.

According to a fifth aspect of the present invention, in the first aspect, the anti-reflection mechanism is, for example, a projection formed on the guard plate. With this configuration,
Light reflection can be prevented, and interruption of the optical axis can be reliably prevented.

According to a sixth aspect of the present invention, in the second aspect, the anti-reflection mechanism is, for example, a convex portion formed on the guard plate. With such a configuration, reflection of light can be prevented, and interruption of the optical axis can be reliably prevented.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of a light beam type safety device of the present embodiment and a press machine using the light beam type safety device. The press machine 10 includes a drive unit 11, a slide 12, a button switch 13, and a control panel 1 of the press machine.
4, and an operation panel 15 and the like. The light beam type safety device 16 includes a light emitting unit 17 and a light receiving unit 18. The light emitting unit 17 includes a plurality of light emitting elements 17-1 to 17-n. Light receiving elements 18-1 to 1
8-n are provided. Further, the light emitting element 17-1
To 17-n and the light receiving elements 18-1 to 18-n are arranged at positions facing each other, and the light of the corresponding light emitting element enters the light receiving element.

FIG. 2 is a side view of the vicinity of the light beam type safety device 16 as viewed from the side. As shown in the drawing, the guard plate 19 is set to the length of the safety distance L, and the distance between the worker and the press machine 10 is also reduced by the length d as compared with the above-described conventional case, so that workability is improved. As shown in FIG. 3, when a hand or the like interrupts an optical axis 20m formed between a certain light emitting element 17-m and a light receiving element 18-m, the light receiving element 1
The incidence of light on 8-m is blocked. In this case, in the related art, there is a risk that the light reflected at the center of the guard plate 19 may enter the light receiving element 18-m.
Since the anti-reflection mechanism 22 for unevenness and the like is provided at the central portion of the light emitting device, reflected light can be surely blocked.

FIG. 4 shows an example of the structure of the antireflection mechanism. In the example of FIG.
a is engraved. In this case, since no convex portion is formed on the surface of the guard plate 19, even if the material or the like moves on the guard plate 19, the material or the like will not be damaged.

FIG. 5 shows a guard plate 19 in which a convex portion 22b is formed substantially at the center. In this case, guard plate 1
Since only the protrusion 22b is formed on the surface of the guard 9, the guard plate 19 can be easily processed.

FIG. 6 shows that a non-reflective plate 22c is formed substantially at the center of the guard plate 19 by bonding or the like. In this case, the non-reflection plate 22c is, for example, a blackboard or a diffuse reflection plate. Note that the present invention is not limited to the above example, and the antireflection mechanism can be realized by another configuration. For example, an anti-reflection paint may be applied, or an opening may be provided at a position corresponding to the guard plate 19.

In the above example, the guard plate 19 provided below the light beam type safety device 16 has been described. However, a guard plate is provided above the light beam type safety device 16 to prevent the reflection at the upper side. Is also good. With this configuration, the safety can be further increased.

As described above, according to the present embodiment, the light emitted from the light emitting element is not reflected on the guard plate and incident on the light receiving element, so that the interruption of the optical axis can be reliably detected. Therefore, the guard plate 19 can be disposed up to the safe distance L, and the worker and the press machine 10 can be disposed.
Can be shortened and workability can be improved.

[0024]

As described above in detail, according to the present invention, workability can be increased while ensuring safety.

Further, the anti-reflection mechanism of the present invention can be realized with a simple structure such as forming irregularities on the guard plate.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a light beam type safety device of the present embodiment and a press machine using the beam type safety device.

FIG. 2 is a side view showing the vicinity of the light beam type safety device.

FIG. 3 is a view showing light blocking when a hand or the like blocks an optical axis formed between a certain light emitting element and a light receiving element;

FIG. 4 is a diagram illustrating a configuration example of an anti-reflection mechanism, in which irregularities are engraved substantially at the center of a guard plate.

FIG. 5 is a diagram illustrating a configuration example of an anti-reflection mechanism, in which a convex portion is formed substantially at the center of a guard plate.

FIG. 6 is a diagram illustrating a configuration example of an anti-reflection mechanism, in which a non-reflective plate is formed at a substantially center of a guard plate by attaching or the like;

FIG. 7 is a diagram illustrating a conventional example.

FIG. 8 is a diagram illustrating a conventional example.

FIG. 9 is a diagram illustrating a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Press machine 11 Drive part 12 Slide 13 Button switch 14 Control panel 15 Operation panel 16 Light beam safety device 17 Light emitting part 18 Light receiving part 17-1-17-n Light emitting element 18-1-18-n Light receiving element 19 Guard plate 20 Optical axis 21 Optical axis 22 Anti-reflection mechanism 22a Unevenness 22b Convex part 22c Non-reflective plate

Claims (6)

[Claims] 1. A light-emitting portion provided with a plurality of light-emitting elements, a light-receiving portion provided with the same number of light-receiving elements facing the light-emitting elements, and formed between the light-emitting elements and the light-receiving elements. And a guard plate positioned below the plurality of optical axes, wherein an anti-reflection mechanism is provided substantially at the center of the guard plate. 2. The light beam type according to claim 1, wherein an upper guard plate is also provided above the plurality of optical axes, and an antireflection mechanism is provided substantially at the center of the upper guard plate. Anti-reflection mechanism of safety device. 3. The anti-reflection mechanism for a light beam type safety device according to claim 1, wherein said anti-reflection mechanism is an unevenness formed on said guard plate. 4. An anti-reflection mechanism for a light beam type safety device according to claim 2, wherein said anti-reflection mechanism is an unevenness formed on said upper guard plate. 5. An anti-reflection mechanism for a light beam type safety device according to claim 1, wherein said anti-reflection mechanism is a convex portion formed on said guard plate. 6. The anti-reflection mechanism for a light beam type safety device according to claim 2, wherein the anti-reflection mechanism is a convex portion formed on the guard plate.