JPS5838807A - Method for measuring length of moving substance - Google Patents

Abstract

PURPOSE:To measure the length of the moving substance without using a speed detector, by the constitution wherein the light, which is emitted from a light projecting device through a pair of reflecting plates that are arranged with a specified interval being provided, perpendicularly traverses the moving line of the material twice, and enters a light receiving device. CONSTITUTION:The light projecting device 3 and the light receiving device are provided over the moving line 20 of the substance 1 with a distance L being provided. The reflecting plates 5 and 6 are provided directly under the device 3 and 4. The light emitted drom the light projector 3 perpendicularly traverses the moving line 20. The light is reflected by the reflecting plates 5 and 6, perpendicularly tranverses the moving line 20 again, and enters the light receiving device 4. The length L is made slightly longer than the length l of the material. When the substance 1 moves at a constant speed, the material 1 shields the incident light for a time period te, enters the zone of the distance L, shields the reflected light from the reflecting plate 6 for a time period tL, and the substance is carried out. The length l of the material 1 is computed by an operator 7 by using the formula l=teXL/tL. Therefore, the length of the moving substance 1 is detected without using the speed detector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for measuring the length of a moving article.

When measuring the length of a moving article, it is known to detect the time during which the article blocks light and the article moving speed, and measure the length of the article from the product of these. However, since this method requires detecting the speed of the article, the measuring device inevitably becomes complicated. In particular, the rotary encoder method is known as a specific method for applying this method to articles moved by a belt conveyor, but there are cases where accurate speed cannot be detected due to belt or roll wear or slip between the belt and roll. There is a disadvantage.

The method for measuring the length of a moving object according to the present invention is a method invented in view of the above-mentioned points. A device is installed to direct the incident light from the floodlight to the first
The reflected light is caused to enter a reflecting plate perpendicularly across the moving line, the reflected light is made to be incident on a second reflecting plate directly below the light receiver, and the second reflected light from the reflecting plate is caused to be incident perpendicularly across the moving line to the light receiver. Receive light, detect the time 11 during which the article blocks the incident light or the second reflected light, and the time tL from the time when the article starts blocking the incident light to the time when the second reflected light starts blocking, and measure the ratio of these times. This method is characterized by:

The present invention will be explained below with reference to the drawings.

In FIG. 1A, 1 is an article, and 2 is a moving line of the article. Reference numerals 3 and 4 are a light projector and a light receiver provided on the moving line a at a distance apart, and this distance is equal to the length of the article 1! It has been made longer than that. Reference numeral 5 indicates a first reflector plate provided directly below the emitter 3, and reference numeral 6 indicates a second reflector plate provided directly below the receiver 4.
It is a reflecting plate, and the incident light 1 from the projector 3 is directed to the moving line 2.
The first reflecting plate 5 enters the first reflecting plate 5 perpendicularly across the
When the first reflecting plate 51 from 1 is incident on the second reflecting plate 6,
The second reflected light r2 from the second reflecting plate 6 perpendicularly traverses the moving line 2 and is received by the light receiver 4.

A light guide can be used to transmit the first reflected light r1, and it is desirable to insert an optical amplifier into this light guide.

FIG. 2 shows the light receiving state of the light receiver when the article moves, with level 1 showing light reception and level O showing light blocking.

As the movement of the article 1 progresses from the state shown in FIG. 1A, the article 1 enters a state in which it blocks incident light 1, as shown in FIG. 1B,
This light blocking period is indicated by tl in the signal in FIG.

After passing through this shading period, the article 1 enters the distance zone as shown in FIG.
The signals in the figure are indicated by t and l.

After passing through this zone residence period, the article 1 enters a state in which it blocks the second reflected light r2, as shown in the first diagram, and this shielding period is indicated by tl in the signal in FIG. 2.

Thus, in FIG. 2, point a corresponds to the starting point at which the article blocks the incident light 1, and point a corresponds to the starting point at which the article 1 blocks the second reflected light r2. The time span between these points is denoted by tL.

Here, the article movement speed is set to V (During the T period during the signal, the movement speed fluctuation can be made to be virtually zero, so ■ is constant)
Therefore, t-''LX L tL.

Therefore, L is constant, and the length l of the article can be measured by calculating tl/th x IJ using a calculator based on the received signal.

The above calculation may be performed by generating pulses with a number of cylinders proportional to tl and tL, converting tl and tl into digital quantities, and calculating the ratio of these digital quantities.

Further, in order to improve measurement accuracy, it is effective to make the distance in the distance zone in FIG. 1A as close to l as possible.

FIG. 3A is a side view showing an embodiment of the present invention in which the length of a plate-shaped article is measured while it is being conveyed by a belt conveyor, and FIG. 3B is a top view thereof.

In Figures 3A and 3B, '20 is a belt conveyor, 1 is a plate-shaped article, 3 is a projector, 5 and 6 are a first reflection plate and a second reflection plate, respectively, and 4 is a light receiver. , and 7 indicate a computing unit, such as a microcomputer, respectively.

8.8 is an air nozzle for preventing dust from adhering to the reflecting plate 5.6.

As described above, according to the method for measuring the length of a moving object according to the present invention, the length of a moving object can be measured simply by using a light projector, a light receiver, and a calculator, without requiring a speed detector for the object. can.

[Brief explanation of the drawing]

1A, 1B, 1C and 1st diagram are explanatory diagrams for showing the present invention; FIG. 2 is an explanatory diagram showing measurement signals in the present invention; FIGS. 3A and 3; B is an explanatory side view and an explanatory top view, respectively, showing the measuring device used in the present invention.

Claims (1)

[Claims] (1) A light emitter and a light receiver are installed in the middle of the movement line of the article, separated by a distance longer than the length of the article, and the incident light from the light emitter is directed perpendicularly to the first reflecting plate directly below the light emitter. The reflected light is incident on a second reflecting plate directly below the light receiver, and the second reflected light from the reflecting plate is received by the light receiver perpendicularly across the moving line, so that the article is not exposed to the incident light or A moving article characterized in that the time 12 for blocking the second reflected light and the time tL from the start of blocking the incident light of the article to the start of blocking the second reflected light are respectively detected, and the ratio of these times is measured. How to measure the length of.