US 3502851 A
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March 24, 1970 JIRO KIIKKIMOTO ET AL 3,502,851
, METHOD OF IDENTIFYING ROLLING STOCK AND A DEVICE THEREFOR Filed May 26, 1965 3 Sheets-Sheet 1 INVENTORS Tiro Kakimaio Kaneln'k MuraLa Walk/4 8M ATTORNEYS March 24, 1970 JIRO KAKIMOTQ ETAL 3,502,851
I METHOD OF IDENTIFYING A ROLLING STOCK AND A DEVICE THEREFOR Filed May 26. 1965 3 Sheets-Sheet 2 r A m S R a E E m N m... m 0 WEN m .uM 0 d. KI 0m M .wa T l BY QS WQWMM March 24,1970 JIRQ KAKIMQTQ ETAL 3,502,851
METHOD OF IDENTIFYING A ROLLING STOCK AND A DEVICE THEREFOR FiledMay 26. 1965 3Sheets-Sheet 5 Fig.9.
INVENTORS 3 r0 Ka H mofo Kdne/v/ko Murda ZLZZ QE M ATTORNEYS United States Patent 3 502,851 METHOD OF IDENTIl YING A ROLLING STOCK AND A DEVICE THEREFOR Jiro Kakimoto, Tachikawa, Tokyo, and Kanehiko Murata,
Yokohama, Japan, assignors to The Furukawa Electric Company Limited, Tokyo, Japan Filed May 26, 1965, Ser. No. 459,063 Claims priority, application Japan, June 1, 1964, 39/30,837; June 24, 1964, 39/ 49,697 Int. Cl. G06k 19/00, 21/00 US. Cl. 23561.12 6 Claims ABSTRACT OF THE DISCLOSURE A method for automatically identifying a moving object in which use is made of a code plate having a plurality of parallel coded fluorescent substance patterns located above and below the horizontal center line of the plate and extending partly into the opposite side of the plate defined by the horizontal center line.
This invention relates to a method of identifying rolling stock running on a railroad and a device therefor. More particularly there is disclosed a method of automatically identifying rolling stock while moving on a railway track by utilizing the photoluminescence of a fluorescent substance associated with a code plate secured to each car said code plate being irradiated by ultraviolet rays.
Along with the recent development of mechanized processing of information on railways, many countries collect the latest information on the movement of rolling stock, particularly freight cars, at centralized data processing stations in order to speed the operation of coupling and to decoupling freight cars and automatically print a list of freight cars bound to a certain destination, thereby improving efficiencies in utilizing freight cars and in processing the paper work related thereto. For such centralized controlling operation, it is necessary to put an individual code symbol on each car to identify it automatically as it passes a predetermined check point by means of said individual code symbols. There are a number of methods proposed for identifying rolling stocks, most of which consist of providing a passive code means secured to the side of the car, which faces check points irradiating a suitable detecting medium, such as a light beam, electromagnetic wave, sound wave, etc., from a reckoning station located at a check point and identifying each rolling stock by detecting by a detector, the signal reflected from said code means secured to the car.
In using electromagnetic waves for said detecting medium, there are two distinctively different methods, i.e. one using the reflection of micro-waves and another using electromagnetic coupling of a long wave and a medium wave. Such methods using electromagnetic waves have an advantage in that the measurement is not adversely affected by natural environmental conditions such as rain, snow and mist. On the other hand, the former method using micro-waves has disadvantages in that a micro-wave generator is expensive and that the measurements are affected considerably by inclination and displacement of the code plate secured to the rolling stock, and the latter method using long and medium waves has disadvantages in that the coding device to be mounted on the rolling stock becomes complicated in construction and accordingly expensive. Moreover the measurement is affected by noise generated in overhead electric power transmission lines used for feeding electric locomotives and cars, and that the use of such electromagnetic waves is limited by government laws and regulations in certain countries.
A method of using monochromatic or multichromatic light as said detecting medium has an advantage in that the code plate to be secured to the rolling stock is simple and inexpensive. However, it is a disadvantage of a detector of this type that the measurement is greatly affected by noises due to natural or artificial light beams and hence the signal to noise ratio i.e. S/N ratio, is low. Modulated light beams may be used to raise the S/N ratio, but the modulator for such purposes is complicated and it is rather difflcult to modulate high frequency waves. Besides, in such method using either modulated or unmodulated light beams, the light beam projected toward the code plate and the light beam returning from the code plate are of the same nature, as
no frequency conversion is carried out at the code plate between said two light beams, and hence such method has a disadvantage in that the measurement by the detector might be interfered with by noises due to light beams reflected from a place other than the desired portion of the code plate or delivered directly to the detector from the light beam projector .without passing the code plate.
Another method of identifying a rolling stock by using sound waves as a detecting means has a disadvantage in that its S/N ratio and reliability are low due to sound noises of the rolling stock and Doppler effect related thereto.
The primary object of the invention is to obviate the above mentioned disadvantages of conventional methods by using the photoluminescence of fluorescent substances caused by irradiation by ultraviolet rays and to provide a novel method for identifying a rolling stock having a high S/N ratio and an excellent reliability by means of simple and inexpensive devices. In carrying out a method in accordance with automaticaly identifying a rolling stock of the invention, a special code plate having a coded pattern of fluorescent substance is secured to a definite place on the side of each car facing check points to be identified, and an identifying station is established at a detecting place provided with a projector to project ultraviolet rays onto the code plate and a detector to detect fluorescent light beams reflected from the fluorescent substance pattern of the code plate, thereby projecting ultraviolet rays having suitable wave lengths against said code plate to excite said fluorescent substance pattern on said code plate. Fluorescent light beams produced by excitation of said coded fluorescent substance pattern of the code plate are then detected by means of a detector, and are transmitted to a central controlling station to operate automatic controlling devices of rolling stock according to coded fluorescent substance patterns.
A salient feature of the invention is to use special code plates having a coded fluorescent substance pattern, and is based on the principle that a fluorescent light beam is produced by a fluorescent substance when energized by ultraviolet rays and the reflected fluorescent light beam is used as a detection light beam. In other words, the detection light beams are produced by converting the wave lengths of the projection light beams by using said code plate, which is a major difference between the method of the invention and conventional methods using light beams for identifying rolling stock. Therefore, according to the invention, those light beams, which are reflected from such portions of the code plate and other than the fluorescent substance pattern thereof and delivered directly from the projector, are possibly interrupted by applying a suitable optical filter in the detector in order to detect only said detection light beams consisting of fluorescent rays. Therefore the S/ N ratio of the method of the invention is highly improved.
For a better understanding of the invention reference is taken to the accompanying drawings, in which FIG. 1 is a diagrammatic view illustrating a general arrangement of the devices for carrying out the method of identifying rolling stock according to the invention;
FIG. 2 is a front view of a first embodiment of a code plate to be mounted on an outside surface of a rolling stock to be identified;
FIG. 3 is a sectional view taken on the line 8-8 of FIG. 2;
FIG. 4 is a perspective view showing construction of the code plate;
FIG. 5 is a front view of a second embodiment of the code plate;
FIG. 6 illustrates pulse wave forms of electrical signals produced by converting the detected light beams reflected from the code plate shown in FIG. 5;
FIG. 7 is a plan view of the third embodiment of the code plate of the invention;
FIG. 8 is a plan view showing a fourth embodiment of the code plate of the invention; and
FIGS. 9 to 12 are curve diagrams showing wave forms of output signals from the detector, which were obtained in actual tests of the invention made under various conditions.
Referring to FIG. 1, reference numeral 1 designates a rolling stock to be identified and 2 is a code plate having a coded fluorescent pattern as shown in FIG. 2, as an example, to be secured to the outside portion of the rolling stock 1. A projector 3 and a detector 4 are provided at a detecting station located at a definite place near by a railway track for the roling stock. The operation of the invention is as follows: When rolling stock is going to pass the detection station, a beam of ultraviolet rays having suitable wave lengths for exciting the fluorescent substance pattern on the code plate is projected from the projector .3 toward the code plate 2 secured to the rolling stock 1, then the fluorescent substance pattern of the code plate 2 is excited by the projected ultraviolet rays to produce fluorescent light beams having wave lengths inherent to said fluorescent substance. The rolling stock is identified by detecting the fluorescent light beam thus produced by means of the detector 4. The detector 4 consists of a filter, a photo-multiplier, an amplifier, a wave shaper, etc., and the output therefrom is transmitted to a central station 5 having a suitable data processing and controlling system. The projector 3 consists of a light source 6 to produce necessary ultraviolet rays and a suitable optical filter glass 7 to pass only required ultraviolet rays and to cut off those light beams produced by said light source which have unnecessary wave lengths. Any lamp producing ultraviolet rays of the necessary wave lengths, such as a high voltage mercury lamp or a fluorescent lamp, can be used as the light source 6. The detector 4 is also provided with suitable optical filter glasses 8, 8' to pass only fluorescent light beams produced by the excitation of the fluorescent substance pattern of the code plate and to prevent undesirable light beams from passing therethrough. Therefore, cut off by the filters 8 and 8 are those parts of the projection light beam which are reflected from non-fluorescent substance portions of the code plate, light beams delivered directly from the projector to the detector, and all other natural and artificial light beams having wave lengths diiferent from those of fluorescent light beams produced by the excitation of the coded fluorescent substance pattern on the code plate, and hence the S/N ratio is substantially improved. The projector and the photosensitive portion of the detector are usually placed in a common container and a shield plate is provided to protect such devices from direct exposure to the sunlight.
FIG. 2 shows a plan view of the first embodiment of the code plate, wherein each fluorescent substance pattern 9 disposed on upper and lower sides of the base line X-X corresponds to a binary number 0 or 1, and four such binary patterns constitute one decimal number. For example the pattern shown in FIG. 2 represents a decimal number 5. In actual applications a combination of a suitable number of code plates as shown in FIG. 2 is used responsive to the number of decimal digits required for numbering the rolling stock. The detector reads said coded pattern on the code plate secured to the rolling stock by means of scanning both upper and lower parts of the code plate, taking advantage of the movement of the rolling stock carrying such code plates.
FIG. 3 is a sectional view taken on the line 5-8 of FIG. 2 showing theconstruction of the code plate, wherein grooves 11 are cut on one side of a transparent base plate 10 made of acrylic resins and fluorescent substance 12 is embedded therein. The front surface of the fluorescent substance is protected by a transparent acrylic resin plate or coating which permits the passage of both ultraviolet rays and visible light beams, and the back side of the base plate is painted with substantially black paint acting to show the fluorescent pattern distinctly, and thus a code plate of simple construction and low cost is produced by using only one base plate. In the embodiment shown in FIG. 2, an acrylic resin plate is used as the base plate because it is most suitable judging from the fact that it easily passes ultraviolet rays and is low in cost, however, it is needless to say that any other material can be used for the base plate as long as such material permits the passage of both the necessary ultraviolet rays and the fluorescent light beams produced by the excitation of the fluorescent substance pattern.
The code plate may also be constructed as shown in FIG. 4, wherein a base plate 14 coated with a fluorescent substance is covered by a transparent protecting plate 15, which permits the passage of ultraviolet rays for exciting the fluorescent substance and also the fluorescent light beam produced by said excitation, and then overlapped by a non-transparent plate 17 provided with suitable slits 16 to obtain the desired fluorescent substance pattern. Thereafter elementary plates in said combination are made into a code plate by pressing or binding them tightly with screws or other suitable means.
FIG. 5 shows the second embodiment of the code plate characterized in that fluorescent patterns shown in FIG. 2, are extended beyond the center line X-X to partly overlap one another. In this case, the detector can scan the code plate, along three parallel lines a-a', X-X, and bb', thereby making it possible to always detect a signal response for each binary digit of code plate in the scanning along the center line X-X. FIG. 6 indicates the output signals from the detector obtained by the use of the code plate shown in FIG. 5. If such a code plate is used, and any pattern, such as portion m of FIG. 5, is undetected due to soil, etc. this failure can be easily found and located by using, for example, the signal corresponding to the center line X-X'; thereby the reliability in identifying the rolling stock is increased. Further, since the pulses detected on the center line X-X' can also be used as clock pulses, the speed of the moving car can also be measured with ease by using said pulses.
Another embodiment of the code plate as shown in FIG. 7 gives a coded symbol made by a combination of different kinds of fluorescent substances such as f, g, h, etc. In this case, the projected ultraviolet rays must have a wave length which can excite each of said fluorescent substances, and the fluorescent light beams produced by such excitations due to the irradiation of said ultraviolet rays are sorted by several kinds of filters fitted to the detector prior to conversion into electrical signals.
In the case of the code plates shown in FIGS. 2, 5, and 7, the scanning operation of such code plates is conducted in the horizontal direction. This is the direction in which rolling stock 1, such as a freight car, travels on a railway line. If it is desired to scan the code plate perpendicularly to the travelling direction of the freight cars, another embodiment of the code plate as shown in FIG. 8 is used, wherein the fluorescent substance patterns i, j, k, etc. are arranged parallel to each other in the travelling direction of the freight car, and the code plate is scanned in the direction shown by the arrow nn, thereby a series of pulse signals spaced at an interval depending only on the scanning speed and independent of the travelling speed of the freight car can be obtained.
Table 1 shows examples of fluorescent substances, projected and detected to be used in the method of the invention.
TABLE 1 Fluorescent substance Wave length of Wave length of Projector 1 Organic fluorescent pigment s.
2 Superhigh voltage mercury lamp and UV pass filter.
3 Y2 filter, interference filter, and photomultiplier having a spectral sensitivity corresponding to 8-4 curve.
A series of actual measurements were taken by identifying rolling stock under various conditions by using a device of the invention having the construction and parts as shown in Table 1, and the results are given in FIGS. 9 to 12 showing output charts of the detector. Six code plates, such as shown in FIG. 2, each representing a decimal digit by four binary digits, were combined together, and a six-digit number thus constructed for rolling stock was read. FIG. 9 shows a detector output under the standard condition when the detector is located at a distance of 1,000 mm. from the code plate secured to the car, and FIG. 10 shows the detector output under the similar condition to that of FIG. 9 when the distance of the detector from the code plate became 1,100 mm., which meant an increase in the distance from the detector to the code plate of 100 mm.
FIGS. 11 and 12 show results of measurements under extremely severe conditions, i.e. said distance from the detector to the code plate was increased to 1,050 mm., which was 50 mm. beyond the standard distance, and the code plate inclined 10 degrees from the travelling direction of a freight car and inclined 5 degrees downward in a vertical direction. In addition to the above, the entire surface of the code plate was covered with snow in the case of FIG. 11 and with dust and smoke in the case of FIG. 12. Such measuring conditions as above are much more severe than those encountered in actual operation using the code plates.
It is apparent from FIGS. 11 and 12 that the detector output signals clearly respond to the coded pattern on the code plate even under extremely severe conditions. Therefore, it shows that the method of the invention is very reliable.
Furthermore, it was ascertained that a satisfactory detector output was obtainable even when a filter glass, which permits the passage of only 2% of fluorescent light beam, was inserted between the photosensitive portion of the detector under standard distance from the detector to the code plate, that is 1,000 mm. This fact shows that the system of the invention will function properly even after the original luminosity of the fluorescent substance is reduced to the level of only 2%.
What we claim is:
1. A code plate comprising a base plate, a fluorescent substance carried by said base plate and adapted to be excited upon the passing of ultraviolet rays towards said plate, and means to establish a coded pattern of fluorescent light beams produced by the excitement of said fluorescent substance, said means comprising a plurality of parallel coded fluorescent substance patterns located above and below the horizontal center line of said plate and extending partly into the opposite side of the plate defined by said line.
2. A code plate according to claim 1, wherein said parallel coded fluorescent substance patterns consist of grooves into which said fluorescent substance is disposed.
3. A code plate according to claim 1, wherein said base plate is made of transparent acrylic resin.
4. A code plate according to claim 1, wherein said base plate is transparent and said fluorescent substance is disposed adjacent one face of said base plate and wherein said means to establish a coded pattern comprises a nontransparent plate adjacent the other face of said transparent plate and having a plurality of parallel slits located above and below the horizontal center line of said plate and extending partly into the opposite side of the plate defined by said line, said fluorescent substance and plate being overlapped and pressed together as a unit adapted to be secured to a suitable outside position on rolling stock.
5. A code plate according to claim 1, wherein said means to establish a coded pattern comprises a plurality of additional fluorescent substance patterns carried by said plate, each having a different exciting wave length.
6. The invention as set forth in claim 1, wherein said plurality of parallel coded fluorescent substance patterns extend transverse to said horizontal center line and partially overlap in the region of said center line.
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3,377,616 4/1968 Auer 23561.115 X THOMAS A. ROBINSON, Primary Examiner R. M. KILGORE, Assistant Examiner US. Cl. X.R.