JPH0367811A - Presence-of-goods detecting method for goods transfer device - Google Patents

Abstract

PURPOSE:To detect even lightweight goods or thin goods by irradiating rays from obliquely above on a goods receiving table, and receiving the reflected light by a photographing means which has been provided so as to be opposite to the upper surface of the goods receiving table, and when the output level thereof is less than a prescribed value, by judging the presence of the goods. CONSTITUTION:The projecting rays of a projector 14A are reflected by a mirror 15A, so that the goods 17 on a receiving table 1 can be irradiated from obliquely above. Thereby, if the goods 17 is present on the goods receiving table 1, the shade is formed, and the reflecting light is reduced. In this condition, when photographing is carried out by a camera 10A, the voltage level of the luminance signal output from the camera 10A decreases. Thus, it can be judged that the goods is present when the voltage level decreases less than a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a load detection method for detecting the presence or absence of a load on a load conveying device.

BACKGROUND OF THE INVENTION As a conventional method for detecting the presence of goods, for example, Japanese Patent Application No. 62
As seen in No. 77693, the presence or absence of a load on the tray is detected by optically reading when the pattern of the detection plate affixed to the side of the tray is disturbed by the vibration of loading the load onto the tray. A method is used in which the presence or absence of a load on the tray is detected by providing light emitters and receivers facing each other on both sides of the path through which the load on the tray passes, and the light is blocked by the load.

Problems to be Solved by the Invention However, with the conventional method of detecting the presence of a load, it is impossible to detect the presence of the load because the tray does not vibrate and the light from the emitter and receiver is not blocked when the load is light or thin. The present invention solves the above-mentioned problem, and aims to provide a load detection method that can detect the presence or absence of a load on a load transfer device even when the load is light or thin. .

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method for detecting the presence of a load in a load transfer device, in which light is emitted diagonally from above onto the top surface of a load receiving platform of a load transfer device that travels on a fixed path to convey loads. An imaging means is provided above the fixed path, facing the upper surface of the loading tray, and receiving the reflected light from the upper surface of the loading tray as input, and when the output level of the imaging means is below a predetermined value, it is possible to determine whether the cargo is present. This is determined to be true.

Effects According to the cargo presence detection method of the present invention, when a cargo is present on the cargo receiving platform of the cargo transport device, a shadow is formed on the receiving platform by light diagonally from above, thereby reducing reflected light input to the imaging means. However, since the output level of the imaging means decreases, the presence of goods is detected. Therefore, even if the load is light or thin, the presence or absence of the load can be reliably detected.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view showing the configuration of a load conveying device using the method of detecting the presence of load in a load conveying device according to the present invention.

In FIG. 1, reference numeral 1 denotes a cargo receiving platform of a load conveying device that travels in the direction of arrow X on a fixed path to convey cargo, and this cargo receiving platform 1 is installed in a machine frame 2 as shown in FIG. A support roller 4 that supports the rectangular cylindrical rail 3 from above and below and a roller 5 for preventing lateral vibration are attached to the upper end of a movable body 6 that is towed by re-chaining or the like, and is attached to the upper end of a movable body 6 that swings left and right via a longitudinal pin 7. Since the rollers 8 attached to both sides of the lower part of the loading platform 1 are supported and guided by a pair of support rails 9, the loading platform 1 can be placed in a normal position without tilting as shown by the solid line in FIG. 2 during normal transportation. By lowering one of the support rails 9 and raising the other at a predetermined location, the load can be moved left and right around the longitudinal pin 7 on the loading platform as shown in the imaginary line in Figure 2. By swinging it, the load is automatically dropped, allowing the load to be sorted.

In addition, in FIG. 1, IOA and IOB are imaging means provided above a fixed path of the loading platform 1, facing the upper surface of the loading platform 1, as shown in FIGS. 3 and 4. This is a camera that uses a CCD as an image sensor, and is located on the downstream side in the running direction They are provided at intervals of /2 or less. 3- As shown in FIGS. 3 and 4, at both ends of the machine frame 2, projectors 14A, 14
B, and mirrors 15A and 15B are provided that project the light projected from the projectors 14A and 14B onto the upper surface of the loading tray from different diagonal directions above, respectively. The reflected light of the light projected onto the upper surface of the loading platform 1 is input.

Further, in FIG. 1, 12A to 12H are chutes for sorting, and each of the chutes 12A to 12H is a loading means for lowering one side of the support rail 9 of the loading platform 1 to drop the load on the loading platform 1. A driving device (not shown) is provided, and a light emitting/receiving device 16 for specifying the loading platform 1 that is being imaged by the cameras IOA and IOB is located upstream of the loading docking machine traveling direction X of the cameras IOA and IOB. It is set in.

A method of detecting the presence or absence of a load on the loading platform 1 will be explained.

As shown in FIG. 5, when a load 17 is placed on the loading platform 1, the light emitted diagonally from above by the mirror 15A creates a shadow on the loading platform 1, and the camera I
The reflected light input to the OA is reduced. Therefore camera IOA
Since the voltage level of the brightness signal output from
It can be determined that the load 17 is on top of the . In addition, camera IOA
, the number of IOBs is two, and the direction of the light irradiated onto the cargo 17 is changed to improve the reliability of detecting the presence of the cargo.

The inventory detection device 18 based on the above principle is configured as shown in FIG. 6, for example. The presence detection device 18 receives the luminance signals output from the cameras IOA and IOB and the cargo receiving platform detection signal from the light emitter/receiver 16 . The brightness signal of the camera IOA on the upstream side in the loading platform traveling direction X is detected by the first voltage detector 1.
9A, and the first voltage detector 19A turns on the output detection signal when the voltage level of the input luminance signal becomes below a predetermined value.

This detection signal is logically ANDed with the loading platform detection signal, and the first
is input to the set terminal of the flip-flop 20. Therefore, when a shadow appears on the loading platform 1 facing the camera 10A during detection of the loading platform 1, the output of the 6 first flip-flop 20 is turned on.

In addition, the luminance signal of the camera IOB, which is provided downstream of the camera IOA in the loading platform running direction X, is transmitted to the second voltage detector 19.
When the voltage level of the input luminance signal becomes below a predetermined value, the second voltage detector 1.9B turns on the output detection signal, and combines this detection signal with the output signal of the first flip-flop 20. A logical product is taken and inputted to the sensor 1~terminal of the second flip-flop 2I. Therefore, the output of the second flip-flop 21 is turned on when it is detected by the camera IOA and the camera JOB that a shadow has appeared on the second side of the receiving platform 1, and the presence of the cargo is detected. The cargo presence detection signal output from the second flip-flop 2 is the output of the second flip-flop 2.
From there, the sorting information is output to a control device that sorts the loads into shoes h12A to 12H. Further, the first and second flip-flops 20.21 are reset when the loading platform detection signal is turned off, and the presence or absence of a load is output for each loading platform 1.

In this way, even if the load 17 is a light or thin product, the presence or absence of the load 17 can be detected because a shadow appears on the load receiving platform 1.

Note that in this embodiment, camera 1. Although two units each of OA, ], IOB projectors 14A, 14B, and mirrors 15A, 15B are provided to improve reliability, it goes without saying that the presence or absence of the load 17 can be detected with each unit. Mirror], 5A, 15B
It is also possible to directly irradiate diagonal light from the projectors 14A, .

In addition, at this time, so that the light is irradiated on the entire surface of the loading platform 1,
It is necessary to provide a distance between the floodlights 14A, 14.8 and the loading platform 1, and problems remain regarding the location of installation.

Effect of the invention As described above, according to the inventory detection method of the present invention.

The presence or absence of a load on the loading platform can be detected by irradiating the loading platform with light from diagonally above the loading platform and detecting the shadow formed by the load by detecting the drop in the output level of the imaging means. Even if the load is light and thin, the presence of the product can be reliably detected.

[Brief explanation of drawings]

The engraving drawing is a perspective view showing the configuration of a load conveying device using the method of detecting the presence of load in a load conveying device of the present invention, FIG. The figures are a plan view and a front view of the load detection unit of the load transfer device, FIG. 5 is a schematic diagram for explaining the load detection method of the load transfer device, and FIG. FIG. 2 is a block diagram of a detection device. 1... Loading platform, 1. OA, IOB...camera, 14
A, 14B... Floodlight, 15A, 15B... Mirror,
17... Cargo, 18... Cargo presence detection device.

Claims (1)

[Claims] 1. Light is irradiated diagonally from above onto the top surface of a load receiving platform of a load carrying device that travels on a fixed path to transport loads, and the light is directed above the fixed path and opposite to the top surface of the load receiving platform to reflect light on the top surface of the load receiving platform. A method for detecting the presence of goods in a cargo conveyance device, which includes an imaging means that receives light as an input, and determines that the goods are present when the output level of the imaging means is below a predetermined value.