JPS59165180A - Reading method of bar code for tire selection - Google Patents

Abstract

PURPOSE:To discriminate the tire accurately by reading an identification code formed in the surface of the tire as projections and recesses, converting it into an electric signal and generating a recess-side hold signal, and shifting it to a projection side by a specific voltage and generating a comparison signal to eliminate the influence of undulations of a tire. CONSTITUTION:The bar code 5 for identification which consists of a recessed part 11, wide bars 12, and narrow bars 13 is formed in the surface 15 of the tire 10, which is rotated to read the code 5 by a displacement gauge 20; and the code is converted into an electric signal, which is supplied to a bar code reader 30. The output of the amplifier 31 of this device 30 is divided into two and one is inputted directly to a comparator 35. The other output is applied to the comparison signal generating circuit consisting of a voltage shifting circuit 32, recessed part signal holding circuit 33, and discharging circuit 34. When the comparison signal is generated, the recess-side hold signal is generated and shifted to the projection side by the specific voltage to generate the comparison signal, which is inputted to the other terminal of the comparator to identify the tire 10 accurately while eliminating the influence of undulations of the tire 10.

Description

[Detailed Description of the Invention] The present invention relates to a method for reading barcodes for tire sorting.
More specifically, the present invention relates to a method for reading a tire sorting barcode, which allows tires to be sorted by quickly and accurately reading a tire sorting barcode formed in an uneven shape on the tire surface during the tire molding stage.

In recent years, the types of tires produced have increased dramatically in response to improvements in automobile performance and diversification of user needs. There is a strong demand for automation of the work of discriminating tires, etc. by scale type. As a result, automatic tire sorting mark reading devices of various types and structures have recently been proposed and put into practical use.

Another method is to form a bar code, which is a combination of a wide bar and a narrow bar, on the tire surface in an uneven manner as the tire sorting mark, and read this bar code with a reading device.

In this case, a combination of wide grooves 2 and narrow grooves 3 are bored in the stamping plate 1 as shown in FIG. If you have access to the tire mold, you can make the tire 1 after molding.
An uneven bar code 5 as shown in FIG. 2 is formed on the bar code 0.

In FIG. 2, 11 is a recess formed by the embossing plate 1, 12 is a wide bar formed by the wide groove 2, 16 is a narrow bar formed by the narrow groove 2, and 14 is a recess formed by the embossing plate 1. A groove mark protrusion 15 is formed on the tire surface by rubber entering a groove formed in the head of a screw 4 for attaching to a mold.

However, when reading the barcode 5 formed by the unevenness on the tire as described above, the tire is rotated and the unevenness of the barcode 5 is detected by the distance from the light source using light such as a laser. If you try to convert this into an electrical signal and decipher the barcode, there is a drawback that the conventional method of reading and processing barcodes printed in black and white cannot be processed in the same way because the tires vibrate as they rotate. . That is, when the tire is rotated, the distance of the tire itself to the light source changes unexpectedly.
The unevenness detection signal of the barcode 5 is displaced with an amplitude of about 3 to 10 times the height of the protrusions of the barcode 5, making it impossible to accurately read the unevenness of the barcode itself.

Also, attach the barcode embossing plate 1 with the screws 4 as described above.
In order to stop the printed barcode, the groove mark protrusion 14 formed by the screw groove 6 is about three times as large as the convex part of the barcode 5, and since this protrusion 14 and the barcode 5 are close to each other, the conventional printed barcode detection processing method However, there is also a drawback that a part of the barcode detection signal is hidden by the protrusion detection signal and cannot be detected.

The purpose of this invention is to quickly and accurately read the tire sorting barcode formed by unevenness on a part of the tire without being affected by the shaking of the rotating tire, as described above, and sort the tires. , to provide a new barcode reading method.

To achieve the above-mentioned purpose, in this invention, a bar code formed in an uneven shape on the tire surface is read, a concave side hold signal is created from an electric signal from an unevenness detector that converts this into an uneven electric signal, and this is used as a convex side hold signal. The present invention is characterized in that a comparison signal shifted by a predetermined voltage is generated, and the level of the electric signal is determined using the comparison signal as a threshold.

The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram illustrating the construction of an embodiment of a tire sorting code reading device for carrying out the method of the present invention. 2
0 is a laser type displacement type, which includes a laser oscillator 21 that emits a laser beam R, a lens 22 that focuses the laser beam R emitted on the surface of the tire 10, and a lens 22 that receives the collected light. The light receiving element 26 converts the signal into an electric signal and outputs it, and a displacement calculating section 24.

60 is a barcode reading circuit for the method of the present invention, and an amplifier 6 that amplifies the electric signal from the displacement meter 20.
1. A voltage shift circuit 62 that shifts the input signal to the convex side by a predetermined voltage; A concave signal hold circuit 66 that holds the uneven input signal at the concave side voltage and delays the voltage to follow the image signal; It is comprised of a discharge circuit 64 that performs discharge so that the output signal immediately follows the displacement of the input signal from the convex side to the concave side, and a comparator 65. In the present invention, the output of the amplifier 61 is branched into two, one being directly connected to one of the input terminals of the comparator 65, and the other being connected via the voltage shift circuit 62, the negative signal hold circuit 66, and the discharge circuit 64. and is connected to the other input terminal of the comparator 65.

□Using the device configured as described above, the present invention accurately reads the uneven barcode 5 formed on the surface of the tire 10 and determines the type of tire 1o. This will be explained using FIGS. 4 and 5.

First, it is assumed that an electric signal 40 as shown by a broken line in FIG. 4(A) appears at a point P on the circuit after the amplifier 61 shown in FIG. 3. For example, the image signal 44 of this electric signal 40 corresponds to the signal from the groove trace protrusion 14 in FIG. , the image signal 45 is the tire surface 1
5, and the concave signal 41 corresponds to the concave portion 11 of the tire 10.

In this invention, the barcode reading circuit 60 branches this electrical signal 40 into two branches, one of which is directly input to a comparator 65. Therefore, the waveform at point Q in the circuit is exactly the same as the electrical signal 40. Then, the other branched electric signal 40 is first applied to a predetermined voltage ΔV(
V) to the image signal side. Therefore, the electrical signal 40
The concave signal 41 in FIG.
It becomes like the concave signal 51.

Eventually, an image signal 44 due to the groove trace protrusion is added to the electric signal 40.
appears, the comparison signal 50 is output to the negative signal hold circuit 66.
Therefore, it cannot follow the image signal 44, and gradually moves toward the image signal 44 with a constant time constant like the image signal 54. (This time constant can be determined depending on the bar width of the 7S-coat and the tire rotation.) Before long, the image signal 44 drops 1.
When the comparison signal 50 matches the convex signal 54, the comparison signal 50 follows the image signal 44 and falls by the discharge circuit 64, and returns to the level of the concave signal 51.

Thereafter, similarly, due to the functions of the concave signal hold circuit 66 and the discharge circuit 64, the comparison signal 50D or the image signal 52 is generated for the image signals 42 and 43 due to the electrical signal 40 of <-12 and 13.
, 53. Then, /<- code 5, the recess 11 of the tire 10 passes, and the electric signal 40 is transmitted to the tire surface 1.
5, this image signal 45 is long and covers almost the entire circumference of the tire 10, so the comparison signal 5
0 is initially set to signal 5 by the function of the concave signal hold circuit 66.
5a, it is below the image signal 45, but eventually exceeds it, and as shown in signal 55b, the voltage difference of the shift voltage ΔV (V) by the voltage shift circuit 62 is maintained, and the image signal 4
Stable at levels higher than 5.

The comparison signal 50 produced as described above is output to point R in the circuit shown in FIG. In this invention, the comparator 6
5, the comparison signal 5o appearing at this point R is compared with the electric signal 40 appearing at point Q, and only when the electric signal 40 exceeds the comparison signal 50, a high level signal H is output to the comparator 65, and otherwise so that a low level signal is output. That is, in this invention, the level of the electrical signal 40 is determined using the comparison signal 50 as a threshold, and the fourth
It is possible to obtain a pulse signal 60 from which a barcode pattern can be accurately identified as shown in FIG.

In the tire sorting barcode reading method of the present invention, the comparison signal 50 is generated by branching the electric signal 40, so that when the tire 10 rotates, it moves up and down, and the electric signal 40 is generated as shown in FIG. Even if the comparison signal 50 oscillates and undulates or vibrates as shown in (A), the comparison signal 50 also oscillates at the same period, so the electrical signal 40 and the comparison signal 50 are relatively
This is the same as the relationship between the electrical signal 40 and the comparison signal 50 shown in FIG. Therefore, in the method of the present invention, even if the tire 10 vibrates unexpectedly while reading the barcode formed on the tire 10, the pulse signal can always be used to accurately identify the barcode pattern as shown in FIG. 5 CB+. You can get 60.

61M (Al reads the barcode 5 with the displacement meter 20 when the tire 10 in FIG. 3 rotates in the direction of the arrow X,
This is an example of an electric current 70 appearing at a point P in the circuit after the amplifier 61. Even if the electrical signal 70 fluctuates in this way, if the method of the present invention is used, the output point S of the comparator 65 will always have the signal of the harmonic I.5 on the tire 10 as shown in FIG. 6(B). A pulse signal 80 whose pattern can be accurately determined can be obtained.

In addition, in FIG. 6 (Bl), the pulse 84 is the groove trace protrusion 1.
4, the pulse group 82 is based on the barcode 5, the pulse 85 is a signal when it transfers to the tire surface 15, and the point Y coincides with point 2 after one rotation of the tire 10. , in the method of this invention, there is no convex signal between these points Y and Z1. Therefore, by using the pulse signal obtained by the method of the present invention, the type of tire can be easily determined.

As explained above, in this invention, a bar code formed in an uneven shape on the tire surface is read, a concave side hold signal is created from an electric signal from an unevenness detector that converts this into an uneven electric signal, and this is converted into an uneven electric signal. By creating a comparison signal shifted by a predetermined voltage to the side and using this comparison signal as a threshold to determine the level of the electrical signal, accuracy can be achieved even if the tire vibrates when rotating the tire and reading the barcode. Since a pulse signal containing a barcode pattern can be created in the process, there is an effect that tires can be sorted accurately without mistakes. In addition, in this invention, since the comparison signal is created based on the barcode concavity (Rjl signal), the protrusion caused by the groove of the barcode embossing plate mounting screw does not affect the reading of the barcode pattern. In addition, the overall length of the plate can be shortened by placing the plate mounting screws in close proximity to the bar forming grooves of the stamping plate, which has the advantage of improving the appearance of the tire after tire molding and improving its marketability.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of an embossing plate attached to a tire molding die to form an uneven code on the tire surface, and Fig. 2 is a perspective view of an embodiment of an embossing plate attached to a tire molding die to form an uneven code on the tire surface. FIG. 3 is a partial sectional view of a tire showing a barcode formed on the surface of the tire; FIG. 4 is a waveform diagram for explaining the present invention in detail, and shows a comparison signal superimposed on an electric signal.
[J(B) is a waveform diagram of a pulse signal obtained by the method of the present invention, FIG. figure(
B) is a waveform diagram of a pulse signal obtained from the waveform of Al, 61iJ (A) is a waveform diagram of point P (point Q) in Figure 3,
FIG. 6fB) is a waveform diagram at point R in FIG. DESCRIPTION OF SYMBOLS 1... Stamping plate, 4... Screw, 5... Bar code, 6... Groove, 10... Tire, 11... Recessed part, 12... IW wide bar, 13... ...Narrow bar, 14... Groove trace, 15... Tire surface, 20.
...Displacement meter, 60...Barcode reader, 62...
Voltage lift circuit, 63, concave signal hold circuit, 34...
・Discharge circuit, 65... Comparator, 40... Electric signal,
50...Comparison A1) Agent Patent Attorney Shin Ogawa
-・ Patent Attorney Masaru Noguchi Shoubenko 411 Shisaishita No. 1] Hikohiφ Figure 1 Enoki Figure 2

Claims (1)

[Claims] While rotating the tire on which the barcode is formed, an unevenness detector installed at a predetermined distance from the barcode detects the unevenness of the barcode and converts it into an electrical signal. The signal is split into two, and one of the electrical signals is used as a comparison signal by a voltage shift circuit, an open signal hold circuit, and a discharge circuit, and when the electrical signal is an open signal, this comparison signal is higher than the electrical signal by the shift voltage. When the electric signal is convex, the comparison signal is held on the open signal side so that it approaches the image signal over time, and the comparison signal created as described above is used as a threshold for the other side. A method for reading tire sorting barcodes that determines the level of electrical signals.