JPH0967009A - Conveyor and multi-beam sensor - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] A single sensor can detect a work having an indeterminate passage position and a work having a small thickness. SOLUTION: A multi-beam sensor 1 is obliquely below a work transfer surface (upper surface of a roller 2) of a roller conveyor device A.
1 is arranged. From the multi-beam sensor 11, the light beam α divided into a plurality of rays is projected along the gap between the rollers 2, and a plurality of detection points are set. When each light beam α is scattered and reflected on the lower surface of the work 1, the light receiving elements 15a, 15b, ...

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier device and a multi-beam sensor used for the carrier device.

[0002]

[Technical background]

(Overall Configuration of Conveyor) What is shown in FIG.
FIG. 3 is a schematic view of a roller conveyor device A capable of sequentially feeding works 1 while maintaining a space between them without colliding with each other or exerting a pressing force on each other. In this roller conveyor device A, the work 1
Rollers 2 which can roll freely are arranged at regular intervals along the conveyance path of the above, and a drive belt 4 is rotated below the rollers 2 at a constant speed by a motor 3 or the like. Also, the roller 2
A lifter 6 driven by a solenoid (electromagnetic actuator) 5 is arranged in each predetermined zone below the drive belt 4 which travels in a contactless manner below. Laura 2
Is normally separated from the drive belt 4 and is free, but when the lifter 6 is raised by driving the solenoid 5, the drive belt 4 is pressed against the roller 2, and the roller 2 is rotationally driven by the drive belt 4. It A sensor S is arranged near the lifter 6 to detect the work 1 passing above the lifter 6, and the sensor S
Is transmitted to the solenoid 5 arranged in the zone on the upstream side of the first stage.

Although only two zones are shown in FIG. 1, three or more zones may be formed (that is,
(3 or more lifters may be installed in the area controlled by one drive belt 4). Further, the roller conveyor device A is configured by continuously installing the structures as shown in FIG.

When the sensor S in a certain zone (for example, the sensor S on the downstream side in FIG. 1) detects the work 1, the solenoid 5 on the upstream side from the sensor S moves from the sensor S as shown in FIG. 1 (a). Upon receiving the detection signal, the lifter 6 is lowered, and a brake (not shown) is applied to the roller 2 to stop the work 1. Therefore, the succeeding work 1 is not sent to the position where the work 1 is detected and collides with it. Then, when the work 1 detected by the sensor S on the downstream side passes over the sensor S, a non-detection signal is sent from the sensor S to the solenoid 5 on the upstream side as shown in FIG. The lifter 6 is sent up, and a driving force is applied to the roller 2 to send the work 1 to the downstream side. By performing such an operation for each zone of the roller conveyor device A,
As shown in FIG. 2, the work 1 is sequentially conveyed in each zone with a predetermined space.

(Conventional Sensor Used in Transporting Apparatus) Conventionally, as the sensor S, a transmission type or retroreflective type photoelectric sensor 7a, 7b and a diffuse reflection type or distance setting type photoelectric sensor 8 are used. It is used. Among these, in the case of the transmissive or retroreflective photoelectric sensors 7a and 7b, it is necessary to install two parts such as a light projecting part and a light receiving part or a light projecting and receiving part and a retroreflective plate, so as shown in FIG. The sensor optical axis is arranged outside the left and right side plates 9 so as to cross the upper surface of the conveyance path. Therefore, the photoelectric sensors 7a, 7
b jumps out of the roller conveyor device A (side plate 9),
It was a ledge and was an obstacle to the work. In addition, a plate-shaped work 1 (for example, a postcard) conveyed on the roller 2
In that case, detection was difficult. Furthermore, the work 1 slides on the roller 2 due to inertia and the work 1 collides with each other,
As shown in FIG. 4, when the work 1 floats and causes a bridge phenomenon, it may be impossible to detect the lifted work 1, and as a result, the work 1 becomes more and more congested at the location. .

In the case of the photoelectric sensor 8 of the diffuse reflection type or the distance setting type, the sensor optical axis passes through the gap between the rollers 2 so that the light emitting / receiving surface faces directly above and below the conveying path. It is located in. In this photoelectric sensor 8, as shown in FIG.
As shown in FIG. 5, the roller 2 can be arranged below the roller 2 so as not to project from the roller conveyor device A, and it is easy to detect a thin work 1 or a work 1 causing a bridge phenomenon. However, in the case of such a diffuse reflection type or distance setting type photoelectric sensor, since the work 1 can be detected only at one position in the width direction of the transport path, when detecting the work 1 whose passing position is indefinite, As shown in FIG. 3, it is necessary to install a large number at each detection position, resulting in high cost.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and its object is to detect a conveyed object whose passing position is indefinite with one sensor. An object of the present invention is to provide a transport device capable of performing the above.

Another object of the present invention is to provide a carrier device capable of detecting a thin object to be conveyed by a single sensor.

Another object of the present invention is to provide a multi-beam sensor used in the above-mentioned transfer device.

[0010]

DISCLOSURE OF THE INVENTION According to a first aspect of the present invention, there is provided a transport device for transporting a transport object and a plurality of light beams emitted from one housing, and reflected light is received by different light receiving elements. Is provided with a multi-beam sensor for detecting a conveyed object, and a conveyance control means for controlling the feeding and stopping of the conveying means based on the output from the sensor.

In the transport apparatus of the present invention, since a multi-beam sensor capable of emitting a plurality of light beams is used as a sensor for detecting a transported object, the detection position is determined for each light beam. By setting, a plurality of detection positions can be set. Therefore, a single sensor can detect a conveyed object whose passing position is indefinite.

A second aspect of the present invention is characterized in that, in the conveying apparatus according to the first aspect, the multi-beam sensor is installed on an oblique side of a conveyed object detection surface.

In this embodiment, since the multi-beam sensor is installed on the diagonal side of the object detection surface, the object can be obliquely irradiated with the light beam.
Therefore, a conveyed product having a small thickness can also be detected. In addition, even when the conveyed object causes the bridge phenomenon, the conveyed object can be detected.

According to a third aspect of the present invention, in the transport apparatus according to the first aspect, the multi-beam sensor has a light emitting element, a light receiving element, and two or more types of diffraction gratings, and the two or more types. Each of the diffracted light spots generated by another diffraction grating is positioned between the diffracted light spots generated by one of the diffraction gratings Is characterized by.

In this embodiment, the diffracted light spots produced by another diffraction grating are positioned between the diffracted light spots produced by one of the two or more types of diffraction gratings. Since the diffracted light spots are arranged on a straight line, the diffracted light spots can be arranged at any position or at any interval by selecting a diffraction grating having an appropriate pattern and arranging it at an appropriate position. . Therefore, it is possible to use a multi-beam sensor having an array pattern according to the size and shape of the transported object.

According to a fourth aspect of the present invention, in the transport apparatus according to the first aspect, the detection method of the multi-beam sensor is a distance setting type.

In this embodiment, since the detection area can be set within a certain distance range, the object passing through the detection surface and the object located at a position distant from the detection surface (such as surrounding machines and workers) Etc.) and the risk of false detection can be reduced.

According to a fifth aspect of the present invention, in the transport apparatus according to the first aspect, the light emitting / receiving surface provided on the housing of the multi-beam sensor is horizontal or obliquely downward. There is.

In this embodiment, since the light emitting / receiving surface provided on the housing of the multi-beam sensor is oriented horizontally or obliquely downward, dirt, cloudiness, dust, etc. are unlikely to adhere to the light emitting / receiving surface. Become. Therefore, it is possible to prevent the detection sensitivity of the multi-beam sensor from being lowered due to the light beam being blocked by dirt or dust on the light emitting / receiving surface.

According to a sixth aspect of the present invention, in the transport apparatus according to the first aspect, the multi-beam sensor outputs the discrimination result by each reflected light beam on the detection surface by OR output. .

In this embodiment, since the multi-beam sensor outputs the discrimination result by OR, the detection signal is output when the conveyed object has passed one of the detection points. Therefore, in the case of an application in which it is desired to detect whether or not the transported object has passed, the subsequent signal processing can be simplified.

According to a seventh aspect of the present invention, in the transport apparatus according to the first aspect, the multi-beam sensor individually discriminates each reflected light beam on the detection surface.

In this embodiment, since each light beam on the detection surface is individually discriminated, it is possible not only to detect that the conveyed object has passed, but also to detect the conveyed object (passage position in the width direction). Can also be detected. Alternatively, it is possible to detect the rough width of the conveyed product.

According to an eighth aspect of the present invention, in the conveying apparatus according to the seventh aspect, at least one of the upper and lower sides and / or the at least one of the left and right sides of the conveying apparatus is directed toward the traveling direction of the conveyed object passage position. It is characterized in that a multi-beam sensor is arranged in.

The width of the conveyed object can be detected by disposing the multi-beam sensor on either the upper side or the lower side. In addition, the height of the conveyed object can be detected by disposing the multi-beam sensor on either side. Further, by disposing the multi-beam sensors on both sides, the width and height of the conveyed object can be known. Therefore, according to this embodiment, the size of the conveyed product can be detected.

A multi-beam sensor according to a ninth aspect is
A light emitting element, a light receiving element, and two or more types of diffraction gratings,
Each diffracted light spot is arranged in a straight line such that a diffracted light spot generated by another diffraction grating is located between diffracted light spots generated by one of the two or more types of diffraction gratings. It is characterized by that.

In this multi-beam sensor, the diffracted light spot generated by another diffraction grating is positioned between the diffracted light spots generated by one of the two or more types of diffraction gratings. Since the diffracted light spots are arranged in a straight line, it is possible to arrange the diffracted light spots at any position or at any interval by selecting a diffraction grating with an appropriate pattern and arranging it at an appropriate position. it can. Therefore, an arbitrary array pattern of diffracted light spots can be obtained.

[0028]

FIG. 5 is a partially cutaway perspective view showing a conveying device, that is, a roller conveyor device A according to an embodiment of the present invention. The entire structure of the roller conveyor device A is the same as that shown in FIGS. 1A and 1B except for the sensor portion, and therefore the illustration thereof is omitted.

In the roller conveyor device A of the present invention, the multi-beam sensor 1 is provided as a sensor S in each zone diagonally below the detection surface (the upper surface of the roller 2).
1 is arranged. That is, as shown in FIG. 5, in the lower space of the roller 2, near the inner side of the side plate 9, the multi-beam sensor 11 is arranged so that the light projecting / receiving surface faces obliquely upward.
Is arranged. The multi-beam sensor 11 includes a light projecting unit (multi-beam light source 12) and a light receiving unit, and a plurality of discontinuous light beams α are emitted from the light projecting unit. These light beams α are in the same plane and the roller 2
It passes through the gap between them. When the work 1 passes the position of any one of these light beams α, the light beam α is diffused and reflected on the lower surface of the work 1, and the reflected light is received by the light receiving portion of the multi-beam sensor 11, and the work 1 is detected. .

FIG. 6 is a perspective view showing an example of the multi-beam sensor 11, in which a multi-beam light source 13, a light-receiving lens 14 and light-receiving element arrays 15a, 15 are provided in a housing 12.
b, ..., etc. are stored. The multi-beam light source 13 constituting the light projecting unit includes a light emitting element 16 such as a light emitting diode (LED) or a semiconductor laser element (LD), and the light projecting lens 1.
7 and a diffraction grating 18. Light emitting element 1
The divergent light emitted from 6 is converted into collimator light by the light projecting lens 17, and then passes through the diffraction grating 18. Here, as shown in FIG.
The light beam α of the next light is used. The light receiving section is composed of a light receiving lens 14 and light receiving element arrays 15a, 15b, ..., And each of the light receiving elements 15a, 15b, 1 which constitutes the light receiving element array.
5 c is arranged at a position where the 0th order light or the ± 1st order light scattered and reflected by the work 1 passing on the upper surface of the roller 2 is condensed by the light receiving lens 14. Therefore, the work 1 is the 0th order light or ± 1 on the detection surface 19 (the upper surface of the roller 2)
When passing through any of the light spot positions of the next light, the light beam α scattered and reflected by the work 1 is received by any of the light receiving elements 1
The light is received by 5a, 15b and 15c, and the work 1 is detected.

FIG. 8 is a block diagram showing the circuit configuration of the multi-beam sensor 11. Oscillation circuit 2
The clock pulse generating circuit 22 outputs a pulse signal having a constant frequency in synchronization with the reference signal generated in 1. The light emitting element drive circuit 23 is the clock pulse generation circuit 2
When the pulse signal is received from 2, the light emitting element 16 is caused to emit light, and as a result, the light emitting element 16 emits pulse light at regular intervals. Each light receiving element 15a that constitutes the light receiving element array,
When the reflected light beam α from the work 1 is received, 15b and 15c output light reception signals. This received light signal is sent to the amplifier 2
After being amplified by 4, it is compared with a predetermined threshold value by the comparator 25. If the amplified received light signal is greater than the threshold value, register 2
The determination signal is output to 6. A pulse signal is input to the register 26 from the clock pulse generation circuit 22,
When the determination signal is received from the comparator 25 at the same time as the pulse signal, it is determined that the work 1 is detected, and the detection signal is output from the output circuit 27. Each light receiving element 15a,
Since the output circuit 27 that outputs the detection signal based on the light receiving signals of 15b and 15c is connected to the OR operation circuit 28, any one of the light receiving elements 15a, 15b and 1
When 5c receives light, it outputs a detection signal from the output terminal 29.

The OR operation circuit 28 has the circuit configuration shown in FIG.
Instead of using, all the light beams α (0th order light and ± 1st order light) emitted from the multi-beam light source 13 may be received by one light receiving element.

As described above, this roller conveyor device A
In this case, the multi-beam sensor 11 is used as a sensor, a plurality of light beams α are emitted along the gaps between the rollers 2, and when any one of the light spots on the detection surface 19 is passed by the work 1, this is detected. Since the detection is performed, it is possible to detect the work 1 whose passing position is indefinite by one sensor.

The multi-beam sensor 11 has a detection surface 1
Since it is arranged obliquely laterally with respect to 9, it is possible to reliably detect the thin plate-shaped work 1. Further, the work 1 can be detected even when the bridge phenomenon occurs.

Further, since the multi-beam sensor 11 is arranged below the roller 2, the sensor is inconspicuous in appearance and does not obstruct the passage of the work 1. further,
Since it does not jump out from the roller conveyor device A, it does not interfere with the work.

The advantage of using the multi-beam sensor 11 is that the detection range can be widened and a high S / N ratio can be realized. For example, when a sensor equipped with a scattering type light source is used, the light beam intensity curve spreads over the whole as shown by 30 in FIG. At the position, the light beam intensity becomes lower than the detection sensitivity, the detection range is narrowed, and the S / N ratio is deteriorated. On the other hand, when the multi-beam sensor 11 is used, the detection points are discontinuous, but a peak-shaped light beam intensity curve such as 31 in FIG. 9 is obtained, and the light beam intensity at the light beam emission point deviates from the center. You can make it bigger even in the place As a result, the detection range can be widened and a high S / N ratio can be realized.

However, when the multi-beam sensor 11 is used, the detection positions (light spot positions) are scattered, so the relationship between the light spot interval g on the detection surface 19 and the minimum width m of the work 1 becomes a problem. That is, when the work 1 passes through the non-detection area between the light spots, the work cannot be detected. In order to prevent this, it is necessary to set the maximum value of the light spot distance g on the detection surface 19 and the light spot distance between the inner surface and the end of the side plate 9 to be smaller than the minimum width m of the work 1. is there.

For example, assuming that the work 1 having the minimum width m is a standard mail such as an envelope or a postcard, the work 1 has a minimum width m of 90 mm. Further, as the multi-beam sensor 11, one that emits three light beams α (0th order light, ± first order light) as shown in FIG. 7 is used, and the multibeam sensor 11 is used as a detection surface 19 as shown in FIG. H = 130 mm from the inner side of the side plate, and L = 30 mm from the inner surface of the side plate 9. In FIG. 10, a = the distance between the inner surface of the side plate 9 and the light spot of the −1st-order light b = the distance between the light spot of the −first-order light and the light spot of the 0th-order light c = the light spot of the 0th-order light and the + 1st-order light The distance between the light spot of d = + 1 order light and the inner surface of the side plate 9. Here, while changing the diffraction angle θ, a = 85
The multi-beam sensor 11 is tilted so as to be mm, and the emission angle φ of the 0th-order light is adjusted, and d = max (a, b, c), that is, d
Was made equal to the largest value among a, b, and c, and was determined as the conveyor width W = a + b + c + d. FIG. 11 shows the relationship between the conveyor width W and the respective values a, b, and c (beam intervals) at this time. From FIG. 11, it can be seen that the conveyor width W in which all of a, b, c, d are smaller than the minimum width 90 mm of the work 1 (a, b, c, d <g) is about 300 mm or less. Therefore, the conveyor width W is about 30
If it is 0 mm or less, the multi-beam sensor 1 as shown in FIG.
11, the values of a, b, and c are read so as to be the values read from the conveyor width W of FIG. 11, and the diffraction angle θ and the exit angle φ of the 0th-order light are determined so that such values are obtained. do it.

(In case of four beams) Also, in FIG.
By passing the light beam α emitted from the light emitting element 16 and converted into the collimated light by the light projecting lens 17 through the diffraction grating 18, the ± first-order light and the ± second-order light (the zero-order light is adjusted by adjusting the diffraction efficiency). The multi-beam sensor 11 emits four light beams α.

Consider a case where the multi-beam sensor 11 as described above similarly detects the work 1 having the minimum width m = 90 mm. The multi-beam sensor 11 is arranged at a position H = 130 mm below the detection surface 19 and L = 30 mm from the inner surface of the side plate 9 as in the case of FIG. In FIG. 12, a = interval between the inner surface of the side plate 9 and the light spot of the −secondary light b = space between the light spot of the −secondary light and the light spot of the −first light c = light of the first light Distance between spot and light spot of + 1st order light d = Interval between light spot of + 1st order light and light spot of + 2nd order light e = + Distance between light spot of 2nd order light and inner surface of side plate 9. While changing the diffraction angle θ, the angle (direction) of the multi-beam sensor 11 is adjusted so that a = 85 mm, and also e = max (a, b, c, d),
The conveyor width was determined as W = a + b + c + d + e. FIG. 13 shows the relationship between the conveyor width W and the respective values a, b, c, d (beam intervals) at this time. From FIG.
All of a, b, c, d, and e are the minimum width g of the work 1 g =
It can be seen that the conveyor width W smaller than 90 mm (a, b, c, d, e <g) is about 300 to 360 mm. Therefore, if the conveyor width W is about 300 to 360 mm, the multi-beam sensor 11 having the configuration as shown in FIG. 12 is used, and the values of a, b, c, and d are set to the values read from the conveyor width W in FIG. It suffices to read the values and determine the diffraction angle θ and the angle of the multi-beam sensor 11 so that such values can be obtained.

(Other example of multi-beam sensor) As described above, since the multi-beam sensor 11 is obliquely arranged with respect to the detection surface 19, a multi-beam sensor using the 0th order light and the ± 1st order light of the diffraction grating 18 is used. Even in the case of the beam sensor 11, the detection surface 1
The light spot spacing g of the light beam α in 9 is not uniform. However, it is preferable from the viewpoint of widening the field of view that the light beams α on the detection surface 19 are evenly spaced.

FIGS. 14 to 16 show the light spot spacing of the light beam α on the detection surface 19 by using two diffraction gratings 18a and 18b (composite grating) combined as the diffraction grating 18 of the multi-beam sensor 11. A method of adjusting g so as to have a desired interval (for example, making light spot intervals equal) is shown. First, as shown in FIG. 14, the light beam α emitted from the light emitting element 16 and collimated by the light projecting lens 17 is used.
Is transmitted through two diffraction gratings 18a and 18b, one diffraction grating 18a generates 0th order light and ± 1st order light, and the other diffraction grating 18b generates only 0th order light. By arranging the 0th-order light spot of the diffraction grating 18b between the 0th-order light spot and the + 1st-order light spot of the diffraction grating 18a, the detection surface 1
The light spot intervals g of the respective light beams α in 9 are made substantially uniform.

FIG. 15 shows a light beam α emitted from the light emitting element 16 and collimated by the light projecting lens 17.
Is transmitted through two diffraction gratings 18a and 18b, one diffraction grating 18a generates 0th-order light and ± 1st-order light, and the other diffraction grating 18b generates ± 1st-order light.
Then, the −1st-order light spot of the diffraction grating 18b is arranged in the center between the 0th-order light and + 1st-order light spots of the diffraction grating 18a, and the + 1st-order light spot of the diffraction grating 18a is -1st order light and + by the diffraction grating 18b
By arranging them in the central portion between the respective light spots of the primary light, the light spot intervals g of the respective light beams α on the detection surface 19 are made substantially uniform.

FIG. 16 shows a light beam α emitted from the light emitting element 16 and collimated by the light projecting lens 17.
Is transmitted through two diffraction gratings 18a and 18b, one diffraction grating 18a generates 0th-order light and ± 1st-order light, and the other diffraction grating 18b generates ± 1st-order light.
Then, on the detection surface 19, the distance between the light spots of the 0th order light and the + 1st order light by the diffraction grating 18a is
The light spot intervals g of the respective light beams α on the detection surface 19 are made substantially uniform by dividing the light spots of the ± first-order lights by b into approximately three equal parts.

(In the case of 5 beams) Here, the relationship between the multi-beam sensor 11 using the composite grating having the structure as shown in FIG. 16 and the conveyor width W will be considered. Consider the case where the work 1 having the minimum width g = 90 mm is detected as in the past. As shown in FIG. 17, the multi-beam sensor 11 has H = 130 mm below the detection surface 19 and L = 3 from the inner surface of the side plate 9.
It is supposed to be placed at a position of 0 mm. In FIG. 17, a = interval between light spots of −1st-order light by the inner surface of the side plate 9 and the diffraction grating 18a b = interval between light spots of −1st-order light and 0th-order light by the diffraction grating 18a c = diffraction grating 18a Between the 0th-order light and the light spots of the -1st-order light by the diffraction grating 18b = The distance between the -1st-order light and the + 1st-order light spots of the diffraction grating 18b = The + 1st-order light and the diffraction grating 18a by the diffraction grating 18b Is the distance between the respective light spots of the + 1st order light due to d = the distance between the light spot of the + 1st order light due to the diffraction grating 18a and the inner surface of the side plate 9. Then, the multi-beam sensor 1 is changed so that the diffraction angle θ of the diffraction grating 18a is changed and a = 85 mm.
The angle of 1 was adjusted and d = max (a, b, c) was set, and the conveyor width was determined as W = a + b + 3c + d. FIG. 18 shows the relationship between the conveyor width W and the values a, b, and c (beam intervals) at this time. From FIG. 18, all of a, b, c, and d are the minimum width g of the work 1 =
It can be seen that the conveyor width W smaller than 90 mm (a, b, c, d <g) is about 360 to 500 mm. Therefore, if the conveyor width W is about 360 to 500 mm, the multi-beam sensor 11 configured as shown in FIG.
The values of b and c may be read, and the diffraction angle θ and the angle of the multi-beam sensor 11 may be determined so that such values can be obtained.

Under the same conditions, about 500 mm
When the multi-beam sensor 11 is used in the roller conveyor device A having the above-mentioned conveyor width W, the multi-beam sensor 11 as described above may be arranged near the inner surfaces of the left and right side plates 9.

(Relationship between received light power and beam projection position)
Now, as shown in FIG. 19, the light beam α having the projection beam power P ₀ is incident on the detection surface 19 and is scattered and reflected by the detection surface 19 (32 indicates the brightness distribution of scattered light), and the light beam α is Let P ₁ be the received light power when the light is received by the light receiving element, for example 15b, the light receiving efficiency P ₁ / P ₀ is P ₁ / P ₀ = (1−cos ² ω) cos θ = sin ² ω · cos θ Is represented. Here, γ is the angle formed by the optical axis connecting the light spot 33 on the detection surface 19 and the center of the light receiving lens 14 with the normal line of the detection surface 19, and ω is the light spot 33 on the detection surface 19 seen from the light receiving lens 14. It is the angle of view. As the distance R of the light spot 3 from the position of the light receiving lens increases, γ → π / 2ω → 0, and thus the light receiving efficiency P ₁ / P ₀ decreases. Therefore, if the projection beam power P _{0 of the} light beam α projected from the multi-beam sensor 11 is constant regardless of the light spot position, the light beam α reflected by the work 1 is received by the light receiving elements 15a, 15b, ... Received power P when light is received at
₁ is not uniform (see FIG. 20), and the signal processing circuit of the multi-beam sensor 11 becomes complicated.

(Multi-Beam Sensor Having Composite Grating) The above-mentioned problem can be solved by using the multi-beam sensor 11 having a composite grating. FIG. 21 is a perspective view showing a multi-beam sensor 11 provided with such a composite grating, which comprises a light projecting section 41 and a light receiving section 42. The light projecting unit 41 projects a plurality of (four in this embodiment) light beams α from the gap between the rollers 2 toward different positions on the detection surface 19. The light receiving unit 42 determines the presence or absence of the work 1 (or outputs a detection signal for determination) by receiving the reflected light beam α from the detection surface 19.

The light projecting section 41 is a light emitting element 1 such as an LED.
6, a light projecting lens 17 for collimating the divergent light from the light emitting element 16, and a composite grating element 43. The composite grating element 43 is for dividing the collimated light into four lights by diffraction, and FIG. 22 (a) is a plan view of the composite grating element 43, and FIG. 22 (b) is the composite grating element 43. A side view is shown. The composite grating element 43 is composed of four grating regions 43a, 43b, 43c, 43d, and each grating region 43a, 43b, 43
The grating directions of c and 43d are determined according to the respective positions so that diffracted light can be projected to different positions. In addition, each grating area 43a, 43b,
43c and 43d are the detection surfaces 19 formed thereby.
Positions of the upper light spot 33 and corresponding light receiving elements 15a, 15b, 15c, 15d for receiving the reflected light beam α.
The area is increased as the distance from the light receiving lens 14 increases and the incident angle of the reflected light beam α from the detection surface 19 with respect to the optical axis of the light receiving lens 14 increases.

In this embodiment, the light receiving element 15a
And the light spot 33 corresponding thereto is the longest, and the off-axis angle of the reflected light beam α incident on the light receiving element 15a is the largest.
The area of the grating region 43d for projecting onto 3 is the largest. And another light spot 3
Corresponding to 3, the area becomes smaller in the order of the grating regions 43c, 43b, 43a adjacent to the grating region 34d.

Further, the light receiving section 42 includes four light receivers 44.
a, 44b, 44c, 44d and a light receiving lens 14 for condensing
It is composed of Light receiving elements 15a, 15b, 15
c and 15d are, as shown in FIG.
44b, 44c, and 44d are housed inside, and openings 45 are formed on the upper surfaces of the light receivers 44a, 44b, 44c, and 44d, respectively. The size of these openings 45 is set according to the amount of light reflected from the corresponding light spot 33 so that the amount of light incident on each of the light receiving elements 15a, 15b, 15c, 15d becomes equal.

As described above, the diffused light emitted from the light emitting element 16 is divided into four light beams α by the composite grating element 43 and is collimated to irradiate the detection surface 19 with the light spot 33 having an appropriate area. To be done.

The light spot 33 generated by each of the grating regions 43a, 43b, 43c, 43d of the composite grating element 43 is the grating region 43a, 43.
The size of the light spot 33 projected from the grating region 43d having the largest area corresponding to the sizes of b, 43c, and 43d is the largest.

The light beam α diffusely reflected by the detection surface 19
Are imaged by the light receiving lens 14 and are received by the light receiving elements 15a, 15b, 15c and 15d of the light receiving unit 42.

If the amount of the reflected light beam α is constant, as the distance between the light spot 33 on the detection surface 19 and the light receiving element becomes longer as described above, the light receiving amount of the light receiving element decreases, and the light receiving lens 14 receives light. The larger the off-axis angle of the reflected light beam α, the smaller the amount of light received by the light receiving element. On the other hand, in the multi-beam sensor 11 using the composite grating element 43, the grating region 4 is associated with the distance between the light spot 33 and the light receiving element and the magnitude of the off-axis angle.
Since the sizes of 3a, 43b, 43c, and 43d are determined, and the size of the light spot 33 is determined by this, the light receiving amount (light receiving power P ₁ ) of each of the light receiving elements 15a, 15b, 15c, and 15d is almost the same. Are equal (Fig. 24
reference).

However, the light receiving elements 15a, 15b, 15
The amount of light received by c and 15d may not always be sufficiently adjusted depending on the size of the grating regions 43a, 43b, 43c and 43d of the grating element 43.

Therefore, the grating regions 43a, 43
The adjustment error of the received light amount due to the area of b, 43c, 43d is
This is corrected by changing the size of the opening 45 of the light receivers 44a, 44b, 44c and 44d. As a result, finally all the light receiving elements 15a, 15b, 15c, 15d
It becomes possible to equalize the received light amounts of.

Further, in the composite grating element 43, the height of the grating is set to each grating region 43.
It may be different for each of a, 43b, 43c, and 43d. Since the diffraction efficiency of the grating element 43 depends on the height of the grating, the grating regions 43a, 43
By adjusting the height of the grating for each of b, 43c, and 43d, each light receiving element 15a, 15b, 15c, 1
The diffraction efficiency can be adjusted for each of the grating regions 43a, 43b, 43c, 43d so that the amount of light incident on 5d is constant.

(Multi-Beam Sensor Having Off-Axis Micro Fresnel Lens Array) Next, as another multi-beam sensor 11 having another configuration, an off-axis micro Fresnel lens array 46 (hereinafter referred to as off-axis micro A Fresnel lens will be abbreviated as off-axis MFL).
This multi-beam sensor 11, as shown in FIG.
The multi-beam light source 13, the light receiving lens 14, and the light receiving element arrays 15a, 15b, ... Are provided. The multi-beam light source 13 is provided with a light emitting element 16 such as an LED, and the light emitting element 16 is arranged above the light emitting element 16, divides the light emitted from the light emitting element 16 into four light beams α, collimates these light beams α, and then respectively positions them at different positions. It is composed of an off-axis MFL array 46 for projecting toward. The light receiving element array includes many light receiving elements. In this embodiment, four light receiving elements 1
Only 5a, 15b, 15c and 15d are used. The light receiving lens 14 receives the diffused reflected light (diffuse reflected light) from the detection surface 19 and receives the corresponding light receiving elements 15a, 15b, 15c, 15.
This is for forming an image on d.

An example of the structure of the off-axis MFL array 46 is shown in FIG. This off-axis MFL array 4
6 is a plurality (4 in this embodiment) of off-axis M
The FLs 46a, 46b, ... Are arranged at predetermined positions. The off-axis MFLs 46a, 46b, ...
As shown in (c), the incident light beam α is deflected in a predetermined direction according to the shape of the unequal-spaced gratings formed therein, and the diffused light is collimated (the collimated light can also be condensed. ) It has a function. Such off-axis MFLs 46a, 46b, ...
It has a grating pattern obtained by cutting a part of the lens 47. The off-axis MFL array 46 shown in FIG. 26A is used to split the outgoing light beam α of the light emitting element 16 into four beams and collimate them, as shown in FIG.
The light spots 33 arranged in a line can be formed on the detection surface 19.

The composite grating element and the off-axis MFL array can be manufactured by, for example, separately manufacturing four types of gratings and off-axis MFL and then bonding them. Further, the diffraction grating, the composite grating element, and the off-axis MFL array described above use a 2P (Photo-Polymerizatio) using a stamper.
It may be integrally formed by the method n) or integrally formed by injection molding.

(Another Embodiment of Multi-Beam Sensor) As the multi-beam light source 13 which constitutes the light projecting portion of the multi-beam sensor 11, one having a structure other than the above may be used. For example, as shown in FIG. 27, the pattern surface of the diffraction grating 18 may be directed toward the light emitting element 16 side. 28 shows a light emitting element 16 and a light projecting lens 17.
And a prism 48 (for example, a prism having a polygonal shape such as a trapezoidal prism),
The light emitted from the light emitting element 16 is converted into collimated light by the light projecting lens 17, refracted by the prism 48, and a plurality of light beams α are emitted in different directions. Also, FIG.
Shown in Figure is a plurality of light emitting elements 16 (light emitting element array)
In the multi-beam light source 13 including the light projecting lens 17, the light beam α emitted from each light emitting element 16 is converted into collimated light by the light projecting lens 17 and emitted in different directions. Further, FIG. 30 shows a multi-beam light source 13 including a light emitting element 16 and a lens array 49, and the light emitted from the light emitting element 16 is the lens array 4
Each lens of 9 is collimated and emitted in different directions. Needless to say, the effect of the roller conveyor device A of the present invention can be obtained even when the multi-beam sensor 11 including the multi-beam light source 13 is used.

(Another Embodiment of Conveying Device) FIG. 31 is a schematic perspective view showing a roller conveyor device A according to another embodiment of the present invention. In this embodiment,
A multi-beam sensor 11 is arranged on the outer side of the side plate 9 and obliquely above the work passing surface (the upper surface of the roller 2). The multi-beam sensor 11 faces diagonally downward,
The plurality of light beams α are projected so as to pass through the gap between the rollers 2.

If the multi-beam sensor 11 is arranged obliquely downward and obliquely above the roller conveyor device A, the light emitting / receiving surface faces downward, so that noise from a fluorescent lamp or the like is less likely to be received and detection sensitivity is increased. Is stable. Also,
Since the light emitting / receiving surface of the multi-beam sensor 11 faces downward, dust, dust, dirt, clouding, etc. are less likely to adhere to the light emitting / receiving surface, and the detection sensitivity of the multi-beam sensor 11 can be prevented from deteriorating due to dust or the like.

Furthermore, if the multi-beam sensor 11 is arranged above the roller conveyer device A, it can be arranged outside the side plate 9, so that the distance from the multi-beam sensor 11 to the detection surface 9 can be made longer and Spot spacing g
Can be made relatively uniform.

Even when the multi-beam sensor 11 is arranged obliquely below the detection surface 9, as shown in FIG. 32, the housing of the multi-beam sensor 11 is arranged horizontally and the light beam α is emitted. By projecting light obliquely upward, dust and the like are less likely to adhere to the light emitting / receiving surface of the housing. On the contrary, the multi-beam sensor 11 may be arranged so that it is directly above and directly below the detection surface. Further, the water repellent treatment may be applied to a glass plate, a transparent resin plate, or the like provided on the light emitting / receiving surface of the housing.

(Still Another Embodiment of the Conveying Device) FIG.
FIG. 6 is a schematic view showing a roller conveyor device A according to still another embodiment of the present invention. In the roller conveyor device A, the detection area 51 of the work 1 by the multi-beam sensor 11 is limited to a predetermined range (the hatched area in FIG. 33) including the work passing surface (the upper surface of the roller 2).
This can be achieved by using a split photodiode or a position detection element (PSD) as each light receiving element of the multi-beam sensor 11 and making the multi-beam sensor 11 a distance detection type. In the case of one beam / one light receiving element, it is a well-known technique to detect a distance using a divided photodiode or a position detection element (PSD) according to the principle of triangulation, and this embodiment is a multi-beam sensor. It has been applied to.

When a diffuse reflection type multi-beam sensor which is not a distance setting type is used, as shown in FIG. 34, a part other than the work 1 is placed above the roller conveyor device A (for example, the hand of the worker 52). If the light beam α of the multi-beam sensor 11 hits the body of the worker 52 and is reflected, there is a possibility that these may be erroneously detected as the work 1. On the other hand, according to this embodiment, the detection area 51
Since it is possible to detect only the lower surface of the workpiece 1 in
The erroneous detection as described above can be prevented, and the reliability can be improved.

(Still Another Embodiment of the Conveying Device) FIG.
FIG. 8 is a diagram showing a circuit configuration of a multi-beam sensor 11 according to still another embodiment of the present invention. In the circuit configuration shown in FIG. 8, the detection signal of each light receiving element is output through the OR operation circuit 28. However, in the circuit configuration shown in FIG. 35, each light receiving element 15a, 15b, ... Is detected so that the passage position of the work 1 (the position of the roller conveyor device A in the width direction) can also be detected. The detection signals output from each of the light receiving elements 15a, 15b, ... Are stored in the memory 53, and the position determining unit 54 determines the passing position of the work 1 and outputs the output terminal 55 to the outside.

Thus, if not only the passage of the work 1 can be detected but also the passage position of the work 1 can be detected, a work sorting function as shown in FIGS. 36 (a) and 36 (b) is provided. It can be used for a carrier device.

In the roller conveyer apparatus A shown in FIG. 36, a sub-conveying line 57 is branched from the main conveying line 56, and a sorter 58 is provided on the side of the main conveying line 56 opposite to the sub-conveying line 57. ing. The sorter 56 includes a plurality of slide shoes 59 and a controller 60 arranged so as to project above the upper surface of the roller 2. Each slide shoe 59 can be moved between the rollers 2 by a drive mechanism (not shown) formed on the lower surface side of the rollers 2, and the multi-beam sensor 11
Is controlled by the controller 60 according to the output signal of Note that 33a, 33 in FIGS.
b, ... Are the light receiving elements 15 when the work 1 passes through.
It is a light spot whose reflected light is detected by a, 15b, ....

In the roller conveyer device A, the works 1 are sorted into the main carrying line 56 and the sub carrying line 57 according to the passage position of the works 1 as follows. For example, as shown in FIG. 33A, when the work 1 has passed a position detected by the light spots 33a and 33b, the passing position is detected by the multi-beam sensor 11. This passing position information is the controller 60
Sent to the slide shoe 5
9 is retracted to the edge of the main transport line 56. Therefore, the work 1 passes through the sorter 58 without being obstructed by the slide shoe 59, and is conveyed straight along the main conveyance line 56 as shown by an imaginary line in FIG.

On the other hand, as shown in the work 1 (a) shown by the imaginary line in FIG. 33 (b), the light spots 33b and 33c are formed.
When passing through the position detected by, the passing position is detected by the multi-beam sensor 11. When the passing position information is sent to the controller 60, the controller 60 appropriately moves the slide shoe 59 toward the side surface of the work 1. Slide shoe 59 that moves at this time
Moves at high speed until it comes into contact with the side surface of the work 1, and when it comes into contact with the side surface of the work 1, it moves slowly while pushing the side surface of the work 1. As a result, the work 1 is shown in FIG.
Like the work 1 (b), the subsequent work 1 (d) is forcibly moved to an area that does not interfere with the passage of the work 1 (d). Next, the work 1 moved along the main transfer line 56 while being pushed by the slide shoe 59 is shown in FIG.
Slide work 59
It is pushed out to the side of the sub-transport line 57 while being changed in direction by and is sent to the sub-transport line 57.

Therefore, according to the roller conveyor device A, the time required for sorting the works 1 can be shortened and the processing efficiency can be improved.

(Still Another Embodiment of Conveying Device) FIG.
FIG. 6 is a partially cutaway perspective view showing a carrier device according to still another embodiment of the present invention. In this roller conveyer apparatus A, one multi-beam sensor 11b is installed facing downward and above the transport path, and the other multi-beam sensor 11a is installed laterally on the side of the transport path.

FIG. 38 shows the upper multi-beam sensor 11b.
FIG. 3 is a diagram showing a circuit configuration of FIG. This multi-beam sensor 1
Similarly to the multi-beam sensor of FIG. 35, 1b determines whether or not the light receiving elements 15a, 15b, ... Detect the work 1 individually, and the work width determination unit 61 detects the width of the work 1 passing through. Then, the width information of the work 1 is output from the output terminal 62.

FIG. 39 is a diagram showing the circuit configuration of the lateral multi-beam sensor 11a. The multi-beam sensor 11a also discriminates whether or not the work 1 is individually detected by the respective light receiving elements 15a, 15b, ..., The work height discriminating unit 63 detects the height of the work 1 passing therethrough, and outputs the output terminal. The height information of the work 1 is output from 64.

Further, the multi-beam sensor 11a is
A work length discriminating unit 65 is provided for detecting the length of the work 1 (dimension in the carrying direction). Each light receiving element 15a,
The detection signals 15b, ... Are input to the counter 66, and the counter 66 obtains the passage time of the work 1 by counting the time during which the detection signal is output. Further, the conveyance speed of the work 1 is obtained from the rotation speed of the speed sensor 67 or the roller 2 or the traveling speed of the drive belt 4. Then, the work length determination unit 65
Calculates the length of the work 1 on the basis of the work passage time and the work transfer speed obtained by the counter 66, and outputs the length information of the work 1 from the output terminal 68.

Therefore, according to the carrying apparatus 1, it is possible to detect the three-dimensional dimensions (width, height, length) of the work 1 at the same time while detecting the passage of the work 1.

In each of the above embodiments, the multi-beam sensor may be designed to be placed horizontally (the light projecting section and the light receiving section are arranged horizontally as shown in FIGS. 5 and 31). It can also be designed to be vertically installed (the light projecting portion and the light receiving portion are arranged in the vertical direction).

[Brief description of drawings]

1A and 1B are schematic views for explaining a structure of a roller conveyor device and an operation for conveying a work.

FIG. 2 is a schematic side view showing a state in which a work is conveyed by each zone by the roller conveyor device.

FIG. 3 is a partially cutaway perspective view showing a structure of a sensor portion in a conventional roller conveyor device.

FIG. 4 is a schematic side view showing a state where a work is causing a bridge phenomenon.

FIG. 5 is a schematic perspective view with a part omitted showing a roller conveyor device according to an embodiment of the present invention.

FIG. 6 is a perspective view showing the above multi-beam sensor.

FIG. 7 is an explanatory diagram showing a principle of detecting a work by the above multi-beam sensor.

FIG. 8 is a diagram showing a configuration of a circuit portion of the above multi-beam sensor.

FIG. 9 is a diagram showing a beam intensity distribution by a multi-beam sensor and a beam intensity distribution by a sensor using diffused light.

FIG. 10 is a diagram showing an arrangement of multi-beam sensors and a definition of a light spot interval on a detection surface.

FIG. 11 is a diagram showing a relationship between a light spot interval (beam interval) and a conveyor width in the above.

FIG. 12 is a diagram showing the arrangement of multi-beam sensors and the definition of the light spot spacing on the detection surface when another multi-beam sensor is used.

FIG. 13 is a diagram showing a relationship between a light spot interval (beam interval) and a conveyor width in the above.

FIG. 14 is an explanatory diagram showing a light beam and a light spot interval when two diffraction gratings (composite gratings) are used.

FIG. 15: Two different diffraction gratings (composite grating)
FIG. 6 is an explanatory diagram showing a light beam and a light spot interval when using the.

FIG. 16 is an explanatory diagram showing a light beam and a light spot interval when two different diffraction gratings (composite gratings) are used.

17 is a diagram showing the arrangement of multi-beam sensors and the definition of the light spot spacing on the detection surface when the multi-beam sensor of FIG. 16 is used.

FIG. 18 is a diagram showing a relationship between a light spot interval (beam interval) and a conveyor width in the above.

FIG. 19 is a diagram for explaining the relationship between the position of a light spot and the light receiving power of a light receiving element.

20 is a diagram showing the light receiving power of each light receiving element shown in FIG.

FIG. 21 is a perspective view showing a multi-beam sensor using a composite grating.

22 (a) and (b) are a plan view and a front view showing the above-described composite grating.

FIG. 23 is a partially cutaway perspective view showing the structure of a light receiver used in the above multi-beam sensor.

FIG. 24 is a diagram showing the light receiving power of each light receiving element in the multi-beam sensor of FIG. 21.

FIG. 25 is a schematic diagram showing a multi-beam sensor using an off-axis MFL array.

FIG. 26A is a plan view showing an off-axis MFL array of the same, FIG.
Diagram showing how it is cut out from the Fresnel lens,
(C) is a perspective view showing the action of off-axis MFL.

FIG. 27 is a schematic view showing a multi-beam sensor having still another configuration.

FIG. 28 is a schematic view showing a multi-beam sensor having still another configuration.

FIG. 29 is a schematic view showing a multi-beam sensor having still another configuration.

FIG. 30 is a schematic view showing a multi-beam sensor having still another configuration.

FIG. 31 is a perspective view showing a transfer device according to still another embodiment of the present invention.

FIG. 32 is a schematic view showing still another arrangement mode of the multi-beam sensor.

FIG. 33 is a schematic view showing a transport device according to still another embodiment of the present invention.

FIG. 34 is a view for explaining the operation of the above-mentioned transport device.

FIG. 35 is a diagram showing another configuration of the circuit portion of the multi-beam sensor according to the embodiment of the present invention.

36 (a) and (b) are schematic plan views showing a transporting device and its operation according to still another embodiment, which utilizes the above-described circuit configuration.

FIG. 37 is a schematic perspective view showing a conveyance device according to still another embodiment of the present invention.

FIG. 38 is a diagram showing a configuration of a circuit portion of one multi-beam sensor in the transport apparatus of the above.

FIG. 39 is a diagram showing a configuration of a circuit portion of the other multi-beam sensor in the transport device of the above.

[Explanation of symbols]

 A roller conveyor device 1 work 2 roller 11 multi-beam sensor 13 multi-beam light source 15a, 15b, ... Light receiving element (array) 16 light emitting element 18, 18a, 18b diffraction grating 19 detection surface 33 light spot 43 composite grating element 43a, 43b, 43c, 43d Grating area 46 Off-axis MFL array 51 Detection area 54 Position determination part 56 Main transfer line 57 Sub-transfer line 58 Sorter 61 Work width determination part 63 Work height determination part 65 Work length determination part 67 Speed sensor

Claims (9)

[Claims] 1. A transport means for transporting a transported object, and a multi-beam sensor for detecting a transported object by emitting a plurality of light beams from one housing and receiving reflected light by different light receiving elements. And a conveyance control unit that controls feeding and stopping of the conveyance unit based on an output from the sensor. 2. The transport device according to claim 1, wherein the multi-beam sensor is installed on an oblique side of a transport object detection surface. 3. The multi-beam sensor has a light emitting element, a light receiving element, and two or more types of diffraction gratings, and between the diffracted light spots generated by one of the two or more types of diffraction gratings. Characterized in that the diffracted light spots generated by another diffraction grating are positioned so that the diffracted light spots are arranged in a straight line.
The transport device according to claim 1. 4. The carrier device according to claim 1, wherein the multi-beam sensor has a distance setting type detection method. 5. The carrier device according to claim 1, wherein the multi-beam sensor has a light emitting / receiving surface provided in a housing thereof in a horizontal direction or an oblique downward direction. 6. The transport apparatus according to claim 1, wherein the multi-beam sensor outputs a discrimination result by each reflected light beam on the detection surface by OR output. 7. The transport device according to claim 1, wherein the multi-beam sensor individually discriminates each reflected light beam on the detection surface. 8. A traveling direction of a conveyed article passing position,
The transport device according to claim 7, wherein a multi-beam sensor is arranged on at least one of the upper and lower sides and / or at least one of the right and left sides. 9. A light emitting element, a light receiving element, and two or more kinds of diffraction gratings, and another diffraction grating is provided between diffraction light spots generated by one of the two or more kinds of diffraction gratings. A multi-beam sensor in which the generated diffracted light spots are positioned so that the diffracted light spots are arranged in a straight line.