JPH0517509B2 - - Google Patents
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- Publication number
- JPH0517509B2 JPH0517509B2 JP59062408A JP6240884A JPH0517509B2 JP H0517509 B2 JPH0517509 B2 JP H0517509B2 JP 59062408 A JP59062408 A JP 59062408A JP 6240884 A JP6240884 A JP 6240884A JP H0517509 B2 JPH0517509 B2 JP H0517509B2
- Authority
- JP
- Japan
- Prior art keywords
- coil
- magnetic
- sensor
- magnetic field
- detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
- G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils
- G01V3/105—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops
- G01V3/107—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops using compensating coil or loop arrangements
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明はフエライト検知センサに関するもので
あり、さらに詳細に言えば副生フエライトを樹脂
等で固めて道路等に敷設した磁気標識体を検知す
るセンサに関するものである。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a ferrite detection sensor, and more specifically, a sensor for detecting magnetic signs placed on roads etc. by hardening by-product ferrite with resin etc. It is related to sensors.
従来、副生フエライトからなる標識体（以下磁
気標識体という）を道路上に敷設し、前記標識体
を車載のセンサで検出することにより車輌を誘導
制御する方法が特願昭55−61435号及び特願昭56
−15455号により提案されている。このものにお
いて磁気標識体を検出する方法として次のものが
提案されている。すなわち、その一つは特願昭55
−141060号により提案されたもので、空心コイル
を２個を用い、一方のコイルで交流磁界を印加
し、他方のコイルで磁気標識体が存在することに
よつて起る磁界の変化を検出する方法である。も
う一つは特願昭57−229064号により提案されたも
ので、空心コイルで交流磁界を発生させ、磁気標
識体が存在することによつて起る磁界の変化を交
流応答型フラツクスゲート磁気センサで検出する
ものである。
Conventionally, there has been a method of guiding and controlling vehicles by laying markers made of by-product ferrite (hereinafter referred to as magnetic markers) on roads and detecting the markers with on-vehicle sensors, as disclosed in Japanese Patent Application No. 55-61435 and Special request 1986
- Proposed by No. 15455. The following methods have been proposed for detecting magnetically labeled substances. In other words, one of them is the patent application filed in 1983.
- This was proposed in No. 141060, and uses two air-core coils. One coil applies an alternating magnetic field, and the other coil detects changes in the magnetic field caused by the presence of a magnetic label. It's a method. The other method was proposed in Japanese Patent Application No. 57-229064, in which an air-core coil generates an alternating current magnetic field, and changes in the magnetic field caused by the presence of a magnetic label are detected using an alternating current response type fluxgate magnetism. It is detected by a sensor.
以上の方法は励起磁界に交流磁界を用いたた
め、道路上に落ちている鉄等の磁性金属と磁気標
識体とを識別することが可能である。すなわち、
金属に交流磁界を印加すると、表面にうず電流が
生じ位相が変化する。この変化は磁性体によつて
起る変化とは逆方向である。たとえば、鉄に交流
磁界を印加すると、上記の２つの変化が重畳する
が、磁界の周波数を上げて約100kHz以上になる
と、うず電流による変化の方が大きくなるため見
かけ上磁性による変化は示さなくなる。したがつ
て、励起磁界に100kHz以上のものを使い、電気
的に位相差を検出することで鉄と磁気標識体とを
識別することができる。以上のように磁気標識体
を用いて車の制御誘導を行う場合、交流磁界を用
いることは不可欠であるが従来のセンサには次の
様な欠点があつた。すなわち、励起磁界が不必要
な範囲まで広がり、センサをとりまく環境（すな
わち囲りの金属）などに影響を受ける。このた
め、実際にセンサを車体等にとりつける場合、金
属ケースでまわりを囲みシールドし、不必要な範
囲に磁場が広がらないようにする必要がある。し
かし、励起コイルに金属を近づけると、うず電流
の影響によりコイルがつくる磁場は減少する。シ
ールドケースがある場合のコイル中心軸上の磁場
は近似的に次式で表わされる。 Since the above method uses an alternating current magnetic field as the excitation magnetic field, it is possible to distinguish between magnetic metal such as iron and magnetic signs that have fallen on the road. That is,
When an alternating magnetic field is applied to a metal, eddy currents occur on the surface and the phase changes. This change is in the opposite direction to that caused by magnetic materials. For example, when an alternating current magnetic field is applied to iron, the above two changes are superimposed, but when the frequency of the magnetic field is increased to about 100 kHz or higher, the change due to eddy current becomes larger, so no change due to magnetism appears. . Therefore, by using an excitation magnetic field of 100 kHz or more and electrically detecting the phase difference, iron and magnetic labels can be distinguished. As described above, when controlling and guiding a vehicle using magnetic markers, it is essential to use an alternating current magnetic field, but conventional sensors have the following drawbacks. That is, the excitation magnetic field spreads to an unnecessary range and is affected by the environment surrounding the sensor (ie, surrounding metal), etc. Therefore, when actually attaching the sensor to a vehicle body, etc., it is necessary to surround it with a metal case and shield it to prevent the magnetic field from spreading to an unnecessary range. However, when metal is brought close to the excitation coil, the magnetic field created by the coil decreases due to the effects of eddy currents. The magnetic field on the central axis of the coil when there is a shield case is approximately expressed by the following equation.
Ｈ＝Ｊ／２〔a2／（a2＋x2）3/2−a2／｛a2＋（ｘ＋2
d）2｝3/2〕
ここで、Ｊ；電流(A)、Ｈ；磁界の強さ（Ａ／
ｍ）、
ａ；コイルの半径(m)、ｘ；コイル軸上
の距離(m)、ｄ；コイルとシールドケー
スの距離(m)である。 H=J/2 [a 2 /(a 2 +x 2 ) 3/2 −a 2 /{a 2 +(x+2
d) 2 } 3/2 ] Here, J: Current (A), H: Magnetic field strength (A/
m), a: radius of the coil (m), x: distance on the coil axis (m), d: distance between the coil and the shield case (m).
上式において右辺の第２項がシールドケースに
よる磁界の減少を表わす。この式よりコイルとシ
ールドケースの距離ｄ(m)が小さければ、磁界の減
少は大きくなる。たとえば、コイルの径に30cmの
ものを用い、シールドケースを５mmの距離に設け
た場合、中心軸上15mmの磁界は約50％減少する。
この様な励起磁界の減少は電気的に損失であり、
検知距離の低下を招く。 In the above equation, the second term on the right side represents the reduction in the magnetic field due to the shielding case. From this equation, the smaller the distance d(m) between the coil and the shield case, the greater the reduction in the magnetic field. For example, if a coil with a diameter of 30 cm is used and a shield case is placed at a distance of 5 mm, the magnetic field at 15 mm on the central axis will be reduced by about 50%.
This reduction in the excitation magnetic field is an electrical loss,
This results in a decrease in detection distance.
また、励起磁界の範囲が広がつているため、セ
ンサの指向性が広くなり、このため磁気標識体を
数枚並べてコード符号化する場合、標識体の間隔
によつては標識体間でセンサの出力が重なり合
い、標識体一枚一枚を識別できなくなる、すなわ
ち分解能が悪いという問題があつた。 In addition, because the range of the excitation magnetic field has expanded, the directivity of the sensor has become wider. Therefore, when several magnetic markers are lined up for code encoding, depending on the spacing between the markers, the sensor may be There was a problem in that the outputs overlapped, making it impossible to identify each marker individually, that is, the resolution was poor.
本発明の目的は、シールドケースが不要でかつ
分解能が高いフエライト検知センサを提供するこ
とにある。
An object of the present invention is to provide a ferrite detection sensor that does not require a shield case and has high resolution.
本発明はギヤツプを有する軟磁性体コアに励起
コイルを巻き、前記ギヤツプの一部に少なくとも
１個の検知コイル又は磁気センサを前記励起コイ
ルによる励起磁界をキヤンセルするように設けた
ことを特徴とするフエライト検知センサである。
すなわち、励起コイルのコアには、たとえばフエ
ライトやパーマロイなどの軟磁性体を用いる。上
記コアに巻かれたコイルが作る磁界はほとんど高
透磁率をもつたコア内に集中し、上記ギヤツプ間
で広く分布する様になる。このため、従来のセン
サの様な磁気標識体近辺以外での磁界の分布は、
ほとんどなく、シールドケースを設ける必要はな
い。またギヤツプ間を小さくすれば、励起磁界を
局在化することができ、より分解能は向上する。
ここで使用する磁気センサとしては交流応答型セ
ンサやホール素子等が考えられる。上記磁気セン
サ又は検知コイルは励起コイルのギヤツプの間に
設け、磁気標識体の接近による磁界変化を検出す
るものである。
The present invention is characterized in that an excitation coil is wound around a soft magnetic core having a gap, and at least one detection coil or magnetic sensor is provided in a part of the gap so as to cancel the excitation magnetic field generated by the excitation coil. It is a ferrite detection sensor.
That is, a soft magnetic material such as ferrite or permalloy is used for the core of the excitation coil. The magnetic field generated by the coil wound around the core is mostly concentrated within the core having high magnetic permeability, and is widely distributed between the gaps. For this reason, the distribution of the magnetic field outside the vicinity of the magnetic label, as in conventional sensors, is
There is almost no need to provide a shield case. Furthermore, by making the gap smaller, the excitation magnetic field can be localized and the resolution can be further improved.
As the magnetic sensor used here, an AC response type sensor, a Hall element, etc. can be considered. The above-mentioned magnetic sensor or detection coil is provided between the gap of the excitation coil and detects changes in the magnetic field due to the approach of the magnetic marker.
以下本発明の実施例について図面を参照して詳
細に説明する。
Embodiments of the present invention will be described in detail below with reference to the drawings.
第１図ａ，ｂは、従来方式のセンサの励起コイ
ル（空心）と本発明の励起コイルの磁束分布の一
例を示すものであり、第１図ａが従来のものを、
また第１図ｂが本発明の励起コイルの磁束分布を
示す。第１図ａに示すように従来の励起コイル１
は円形の空心コイルとして形成されているから、
コイルの表面と裏面に磁極が表われ、磁束３は表
面から裏面に大きな円を描く分布となる。これに
対し、第１図ｂにおいて本発明はフエライト、パ
ーマロイなどの軟磁性体コア１３にギヤツプ１２
を形成し、該コア１３に励起コイル２を巻き付け
たものである。本発明によれば、磁性はコア１３
のギヤツプ１２を挾む両端に表われ、このため磁
束４はギヤツプ間のみに局在化して分布する。第
２図は第１図に示した励起コイルを使つたセンサ
を示すもので、第１図ａは従来のセンサを、第２
図ｂは本発明のセンサの一実施例を示す。第２図
ｃに示すように従来のセンサは励起コイル１０に
交流磁界を発生させ、検出コイル１１は該コイル
を貫ぬく励起磁束が０になるように（以下磁気平
衡という）励起コイル１０と組み合わせて設けて
いた。今この磁界中に、磁気標識体を接近させる
と、検出コイル１１を貫ぬく磁束の平衡がくず
れ、検出コイル１１に誘導電圧が生じ、この誘導
電圧を検出することで標識体の接近を検知してい
た。これに対し、第２図ｂにおいて、本発明は第
１図ｂに示したようにギヤツプ１２をもつた閉ル
ープ形のフエライトコア１３に巻いた励起コイル
１４で交流磁界を発生させ、さらにコア１３のギ
ヤツプ１２の間に２つの検知コイル１５，１６を
該コイルの検出磁界方向（以下感度軸という）１
８がコアの中心軸１７に平行でかつ対称になるよ
うに配置したものである。検知コイル１５，１６
は、それぞれのコイルに誘導される電圧が０にな
る様に電気的に接続し、端子１９を設けてある。
今この磁界中に磁気標識体が接近すると、検知コ
イル１５，１６を貫く磁束のバランスがくずれ、
端子１９には誘導電圧が生じる。この誘導電圧を
検出することにより、磁気標識体の接近を検知す
る。尚、実施例では検知コイルを用いたが、これ
に代えて交流応答型フラツクスゲートまたは、ホ
ール素子などの磁気センサを用いてもよい。次に
第２図ａのセンサにおいて、励起コイル１０に30
mmφ（100turn）、検出コイル１１に20mmφ
（100turn）のものを用い、一方第２図ｂのセンサ
において、励起コイル１４を50mm×35mm、幅10mm
の“口”字形でギヤツプ20mmを有するフエライト
コア１３に巻いたもの、検知コイル１５，１６は
５mmφ×５mm（100turn）でコイルの中心軸はコ
アの軸１７より５mmの位置に固定し用い、磁気標
識体を検知した結果を第３図、第４図に基づき説
明する。第３図は、第２図のセンサを用い、巾50
mm、厚み３mmのフエライト標識体３２を検出した
検出曲線を示す。縦軸は、検出コイルに誘導され
る電圧を、横軸はセンサ中心と標識体中心との中
心間距離を示す。図より明らかな様に従来センサ
による検出曲線３０は本発明のセンサによる検出
曲線３１に比較して標識体の端でなだらかであ
り、本発明のセンサは従来のものに比較して分解
能が優れていることを示している。 Figures 1a and 1b show an example of the magnetic flux distribution of the excitation coil (air core) of a conventional sensor and the excitation coil of the present invention.
Further, FIG. 1b shows the magnetic flux distribution of the excitation coil of the present invention. As shown in Figure 1a, a conventional excitation coil 1
is formed as a circular air-core coil, so
Magnetic poles appear on the front and back surfaces of the coil, and the magnetic flux 3 is distributed in a large circle from the front surface to the back surface. In contrast, in FIG. 1b, the present invention has a gap 12 in a soft magnetic core 13 made of ferrite, permalloy, etc.
The excitation coil 2 is wound around the core 13. According to the invention, the magnetic properties of the core 13
The magnetic flux 4 appears at both ends sandwiching the gap 12, and therefore the magnetic flux 4 is localized and distributed only between the gaps. Figure 2 shows a sensor using the excitation coil shown in Figure 1, and Figure 1a shows a conventional sensor with a second
Figure b shows an embodiment of the sensor of the invention. As shown in FIG. 2c, the conventional sensor generates an alternating magnetic field in an excitation coil 10, and the detection coil 11 is combined with the excitation coil 10 so that the excitation magnetic flux penetrating the coil becomes zero (hereinafter referred to as magnetic equilibrium). It was set up. Now, when a magnetic marker approaches this magnetic field, the balance of the magnetic flux passing through the detection coil 11 is disrupted, and an induced voltage is generated in the detection coil 11. By detecting this induced voltage, the approach of the marker can be detected. was. In contrast, in FIG. 2b, the present invention generates an alternating current magnetic field with an excitation coil 14 wound around a closed-loop ferrite core 13 with a gap 12 as shown in FIG. Two detection coils 15 and 16 are connected between the gap 12 in the detection magnetic field direction of the coils (hereinafter referred to as the sensitivity axis) 1
8 are arranged parallel to and symmetrically with the central axis 17 of the core. Detection coils 15, 16
are electrically connected and provided with a terminal 19 so that the voltage induced in each coil becomes zero.
If a magnetic label approaches this magnetic field, the balance of magnetic flux passing through the detection coils 15 and 16 will be disrupted.
An induced voltage is generated at the terminal 19. By detecting this induced voltage, the approach of the magnetic label is detected. Although a detection coil is used in the embodiment, an AC responsive flux gate or a magnetic sensor such as a Hall element may be used instead. Next, in the sensor of FIG. 2a, the excitation coil 10 is
mmφ (100turn), 20mmφ for detection coil 11
(100 turns), and on the other hand, in the sensor shown in Fig. 2b, the excitation coil 14 is 50 mm x 35 mm and 10 mm wide.
The detection coils 15 and 16 are 5 mmφ x 5 mm (100 turns), and the center axis of the coil is fixed at a position 5 mm from the core axis 17. The results of detecting the marker will be explained based on FIGS. 3 and 4. Figure 3 shows a sensor with a width of 50 mm using the sensor in Figure 2.
A detection curve for detecting a ferrite labeled body 32 with a thickness of 3 mm and a thickness of 3 mm is shown. The vertical axis shows the voltage induced in the detection coil, and the horizontal axis shows the center-to-center distance between the center of the sensor and the center of the marker. As is clear from the figure, the detection curve 30 by the conventional sensor is gentler at the edge of the label than the detection curve 31 by the sensor of the present invention, and the sensor of the present invention has superior resolution compared to the conventional sensor. It shows that there is.
第４図は巾50mmの磁気標識体４０を10mm間隔で
並べた場合の検出曲線を示す。第４図ａは従来セ
ンサの検出曲線４１を、第４図ｂは本発明のセン
サの検出曲線４２を示す。図より明らかな様に従
来センサの検出曲線４１は標識体間を明確に識別
できない。これは一枚一枚の検出曲線は第３図３
１の曲線の様に標識体の端でブロードでありこの
ため標識体間で重なり合うために起る。このため
標識体一枚一枚を検出するためには２つのフエラ
イト標識体４０，４０の間隔をもつとひろくする
必要がある。本発明センサは第３図で示すように
分解能がよいため、第４図ｂに示すように標識体
の間隔が10mmでも標識体一枚一枚を検出すること
ができる。 FIG. 4 shows a detection curve when magnetic labels 40 each having a width of 50 mm are arranged at intervals of 10 mm. FIG. 4a shows a detection curve 41 of the conventional sensor, and FIG. 4b shows a detection curve 42 of the sensor of the present invention. As is clear from the figure, the detection curve 41 of the conventional sensor cannot clearly distinguish between markers. The detection curve for each sheet is shown in Figure 3.
Like the curve 1, the curve is broad at the ends of the markers, and this occurs because the markers overlap. Therefore, in order to detect each marker, it is necessary to increase the distance between the two ferrite markers 40, 40. Since the sensor of the present invention has a good resolution as shown in FIG. 3, it is possible to detect each marker one by one even if the distance between the markers is 10 mm as shown in FIG. 4b.
第５図は本発明の他の実施例を示すもので、第
２図ｂでは２個の検知コイルを用いたが、本実施
例は１個の検知コイルで磁気平衡を検出する場合
を示すものである。すなわち、第５図において、
検知コイル５０はコア１３のギヤツプ１２の中心
に、該コイル５０の感度軸５１がコアの中心軸５
２に対して垂直となるように設けたものである。 Fig. 5 shows another embodiment of the present invention, in which two detection coils were used in Fig. 2b, but this embodiment shows a case where magnetic equilibrium is detected with one detection coil. It is. That is, in FIG.
The detection coil 50 is located at the center of the gap 12 of the core 13, and the sensitivity axis 51 of the coil 50 is aligned with the central axis 5 of the core.
2. It is provided perpendicularly to 2.
第６図は第５図に示す実施例のセンサでフエラ
イト標識体６０を検出した検出曲線６１を示す。
検出曲線６１は図より明らかな様に標識体６０の
中心で最小となり、端と中心の間で最大値を示す
曲線となる。 FIG. 6 shows a detection curve 61 when the ferrite label 60 was detected by the sensor of the embodiment shown in FIG.
As is clear from the figure, the detection curve 61 has a minimum value at the center of the label 60 and a maximum value between the edge and the center.
以上の様に本発明はコア入りの励起コイルと、
検知コイル又は磁気センサとを組み合わせること
により、励起磁界を局在化するようにしたため、
シールドケースを必要とせず、しかも分解能を向
上できる効果を有するものである。
As described above, the present invention includes an excitation coil with a core,
By combining with a detection coil or magnetic sensor, the excitation magnetic field is localized, so
This does not require a shield case and has the effect of improving resolution.
第１図ａ，ｂは励起磁場分布を示す図、第２図
ａ，ｂは従来方式と本発明の方式のセンサの一実
施例を示す構成図、第３図、第４図は第２図ａ，
ｂに示したセンサによる検出曲線図、第５図は本
発明のセンサの他の実施例を示す構成図、第６図
は第５図のセンサによる検出曲線図である。
図において、１，２……励起コイル、３，４…
…磁束、１０……励起コイル、１１……検出コイ
ル、１２……コアのギヤツプ、１３……フエライ
トコア、１４……励起コイル、１５，１６……検
出コイル、１７……中心線、１８……感度軸、１
９……検出コイル端子、３２……フエライト標識
体、４０……フエライト標識体、５０……検出コ
イル、５１……感度軸、５２……中心軸、６０…
…フエライト標識体。
Fig. 1 a and b are diagrams showing the excitation magnetic field distribution, Fig. 2 a and b are configuration diagrams showing an example of the sensor of the conventional method and the method of the present invention, and Figs. a,
FIG. 5 is a block diagram showing another embodiment of the sensor of the present invention, and FIG. 6 is a detection curve diagram by the sensor shown in FIG. In the figure, 1, 2... excitation coil, 3, 4...
... Magnetic flux, 10 ... Excitation coil, 11 ... Detection coil, 12 ... Core gap, 13 ... Ferrite core, 14 ... Excitation coil, 15, 16 ... Detection coil, 17 ... Center line, 18 ... ...Sensitivity axis, 1
9...detection coil terminal, 32...ferrite labeled body, 40...ferrite labeled body, 50...detection coil, 51...sensitivity axis, 52...center axis, 60...
...Ferrite labeled body.
Claims (1)
を巻き、前記ギヤツプの一部に少なくとも１個の
検知コイル又は磁気センサを前記励起コイルによ
る励起磁界をキヤンセルするように設けたことを
特徴とするフエライト検知センサ。1. Ferrite detection characterized in that an excitation coil is wound around a soft magnetic core having a gap, and at least one detection coil or magnetic sensor is provided in a part of the gap so as to cancel the excitation magnetic field by the excitation coil. sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59062408A JPS60205273A (en) | 1984-03-30 | 1984-03-30 | Ferrite detection sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59062408A JPS60205273A (en) | 1984-03-30 | 1984-03-30 | Ferrite detection sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60205273A JPS60205273A (en) | 1985-10-16 |
| JPH0517509B2 true JPH0517509B2 (en) | 1993-03-09 |
Family
ID=13199281
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59062408A Granted JPS60205273A (en) | 1984-03-30 | 1984-03-30 | Ferrite detection sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60205273A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0790051B2 (en) * | 1986-01-23 | 1995-10-04 | 株式会社三共 | Ball game machine |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5764188A (en) * | 1980-10-08 | 1982-04-19 | Res Dev Corp Of Japan | Ferrite detector |
| JPS58213276A (en) * | 1983-05-27 | 1983-12-12 | Hitachi Ltd | Detector of magnetic material or conductive substance |
-
1984
- 1984-03-30 JP JP59062408A patent/JPS60205273A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60205273A (en) | 1985-10-16 |
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