CA1198165A - Means for metallic object detection - Google Patents
Means for metallic object detectionInfo
- Publication number
- CA1198165A CA1198165A CA000402340A CA402340A CA1198165A CA 1198165 A CA1198165 A CA 1198165A CA 000402340 A CA000402340 A CA 000402340A CA 402340 A CA402340 A CA 402340A CA 1198165 A CA1198165 A CA 1198165A
- Authority
- CA
- Canada
- Prior art keywords
- coil
- signal
- transmitter
- signal emitted
- amplitude
- 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
Links
- 238000001514 detection method Methods 0.000 title claims description 4
- 230000005672 electromagnetic field Effects 0.000 claims abstract description 14
- 230000001702 transmitter Effects 0.000 claims description 2
- 230000003321 amplification Effects 0.000 abstract description 6
- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000002800 charge carrier Substances 0.000 description 4
- 230000000977 initiatory effect Effects 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000005293 physical law Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
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
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Remote Sensing (AREA)
- Geology (AREA)
- Environmental & Geological Engineering (AREA)
- Electromagnetism (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
- Control Of Vending Devices And Auxiliary Devices For Vending Devices (AREA)
- Control And Other Processes For Unpacking Of Materials (AREA)
Abstract
ABSTRACT
The invention relates to metallic object detector comprising a coil system with a transmitter coil for generating an electromagnetic field and a receiver coil which is arranged in such a way that an electromotive force is induced in the coil when the coil is affected by the field generated by a metallic object and the field generated directly by the transmitter coil. The invention relates particularly to the transmitter side and includes a feed-back circuit for keeping the amplitude of the electromagnetic field generated by the transmitter coil constant. The transmitter side comprises, specifically, an oscillator which generates a sinusoidal signal for the transmitter coil and a variable attenuation/amplification circuit which controls the amplitude of the sinusoidal signal. The attenuation/amplification circuit is controlled by a signal which is emitted by the coil system after the sinusoidal signal has been rectified and compared with a reference voltage. In one embodiment it is the signal emitted by the receiver coil due to the directly induced electromotive force in the coil which is fed back but in a second embodiment it is a signal emitted by the transmitter coil which is fed back.
The invention relates to metallic object detector comprising a coil system with a transmitter coil for generating an electromagnetic field and a receiver coil which is arranged in such a way that an electromotive force is induced in the coil when the coil is affected by the field generated by a metallic object and the field generated directly by the transmitter coil. The invention relates particularly to the transmitter side and includes a feed-back circuit for keeping the amplitude of the electromagnetic field generated by the transmitter coil constant. The transmitter side comprises, specifically, an oscillator which generates a sinusoidal signal for the transmitter coil and a variable attenuation/amplification circuit which controls the amplitude of the sinusoidal signal. The attenuation/amplification circuit is controlled by a signal which is emitted by the coil system after the sinusoidal signal has been rectified and compared with a reference voltage. In one embodiment it is the signal emitted by the receiver coil due to the directly induced electromotive force in the coil which is fed back but in a second embodiment it is a signal emitted by the transmitter coil which is fed back.
Description
~ 23260-303 The present invention relates to metalllc object detection means com-prising a coil system with a transmitter coil for generating an electromagnetic field and a receiver coil which is arranged in SUCil a way tha-t an electromotive force is induced in the coil when the coil is affected by the field generated by a metallic object and the field generated directly by the transmitter coil and, more particularly, the invention relates to means for keeping the amplitude of the electromagnetic field generated by the transmitter coil con-stant.
Metallic object detection means of this type may for instance be used in apparatus for detecting metallic objects in earth in connection with geophysical prospecting but can also be used in electromagnetic proximity fuses for initiating the charge of a charge carrier, for instance a missile, pro-jectile, shell or the like, when this passes a metallic object at a certain dis-tance. In both of said applications, signal processing means are arranged to emit an active output signal in dependence on the interEerence electromotive force induced in the receiver coil due to the metallic object.
In Swedish patent No. 77.06158-8, which issued on April 30, 1981 to Aktiebolaget ~ofors, metallic object detector means of the afore-mentioned type are illustrated and used in an electromagnetic proximity fuse for initiating the charge of a charge carrier when a metallic object is located at a well de-fined distance from the charge carrier, preferably a small distance of 0.5 -1.5 m. The advantage of generating an electromagnetic field for use in a proxi-mity fuse is that such fuse acts independently of the earth-magnetic field and also independently of whether or not the target is built up of iron in contrast to previously known magnetic proximity fuses.
The proximity fuse according to said Swedish patent specification is mainly characterized in that the receiver coil is located in front of and at a certain distance from the transmitter coil, preferably in the nose section of the charge carrier, so that in addition to the interference electromotive force ~/ -- 1 --A ~
also an electromotive force is induced in the receiver coil under direct influ-ence of the electromagnetic field generated by the transmitter coil and that the signal processing means are arranged to separate the interference electro-motive force from the directly induced electromotive force and to emit the active output signal to means for initiating the charge.
In geophysical prospecting as well as in proximity fuses it is desired to keep the amplitude of the generated electromagnetic field constant, i.e., independent of frequency, temperature, and different disturbing factors which may affect the detector means. I~ is therefore desired to design the trans-mitter unit in such a way that the requirement of a constant amplitude of the field can be better fulfilled than previously. This also represents an advan-tage with respect to the manufacturing of the detector means as the tolerance requirements of for instance the transmitter coil can be reduced It is therefore an object of the present invention to provide detector means in which the amplitude of the ele~r, ~gn~tic field gencrated by the tra[ls-mitter coil can be easily kept constant. The invention is characterized by an oscillator for generating a sinusoidal signal for the transmitter coil, means ~or controlling the amplitude of the sinusoidal signal, a feed-back circuit com-prising means for rectifying a signal emitted by the coil system and means for comparing said rectified signal with a reference voltage and in dependence of '` L~ said comparison-3*~ an output signal to said means for controlling the ampli-tude of the sinusoidal signal. In one embodiment it is the signal emitted by the receiver coil due to the directly induced electromotive force in the coil which is fed back but in a second embodiment it is a signal emitted by the transmitter coil which is fed back.
The invention will now be described in more detail with reference to the accompanying drawings in which:
Figure 1 is a block diagram of a first embodiment of the invention;
and Figure 2 i5 a block diagram of a second embodiment of the inven~ion.
The block diagram of Figure l illustrates the basic structure and function of the detector means according to the invention. The detector means may for instance be utili~ed in a metal detector for geophysical prospecting or in a proximity fuse for initiating a charge near a metallic object (the target).
Both of said applications include a coil system which comprises a transmitter unit in the form of a transmitter coil for generating an electromagne~ic field which is distributed in space according to known physical laws and a receiver unit in the form of a receiver coil which is located so that it is affected by the electromagnetic field generated by the metallic object in which case an in-terference electromotive force is induced in the coil. The recciver coil is also ~ocated in such a way that a part of the electromagnetic field, generated by the transmitter coil, falls directly on the receiver coil and gives r;se to a direct-ly induced electromotive force in ~he coil. By means of signal processing means the interference electromotive force is then separated from the directly induced electromotive force and an active output signal is provided in dependence of the interference electromo$ive force only.
The signal processing of the interference electromotive force is not a part of this invention and is therefoTe not described here. Reference should be made to the above-mentioned Swedish patent specification No. 77.06158-8 if more information is re~uired regarding the signal processing aspect. The present invention relates to the transmitter unit of the detector means and includes a feed-back circuit which makes it possible to keep the amplitude of the electro-magnetic field generated by -the tr~nsmitter coil constant.
More particularly, the block diagram illustrated in Figure l comprises an oscillator 1 for generating a sinusoidal signal X oE a specific freqwency and amplitude. Signal X is fed via one input of a variable attenuation/amplification circuit 2 to a tuned circuit comprising a current feed back amplifier 3, a capa citor C, a driver unit 4 and a transmitter coil 5. The amplifier 3 and the driver unit ~ provide the necessary current I for the transmitter coil 5. The transmitter coil then generates an electromagne-tic field with the same frequency as the sinusoidal signal X. This field is distributed in space according to known physical laws and a part of the field falls directly on a receiver coil 6 located close to the transmitter coil 5 or at a certain distance from said coil, depending on the field of application. An electromotive force is then induced in the receiver coil 6 and gives rise to a receiver signal Im which is fed to an integrator 7 and a rectifier 8 in which the signal is integrated and rectified, respectively. The signal is then compared with a reference voLtage, Uref in a comparator 10, and if the sum of the rectified signal and the reference voltage is not equal to zero, then an error signal is obtained which is integrated by means of an integrator 9 to give rise to a signal Y, which is fed to the other input of the variable attenuation/amplification circuit 2 to control the output of circuit 2 according to the values of the sinusoidal signal X and the integrat-ed error signal Y.
The block diagram illustrated in Figure 2 is similar to that of Figure 1 but in this second embodiment the receiver coil is not used in the invention.
Instead, the transmitter coil voltage signal Is is fed back and rectified by the rectifier 8, the rectified signal then being fed to comparator 10 as before.
Specifically, the feed-back circuit is connected to the terminal 11 at the junc-tion of the capacitor C and the transmitter coil 5 in the tuned circuit.
Another difference between the first and second embodiments relates to the variable attenuation/amplification circuit 2. In the second embodiment _ 4 --~ 3~
this circuit is connected to oscillator 1 in an oscillator feed-back configura-tion circuit, but as with the first embodi.ment the integrated error signal Y is also used here to control the variable attenuation/amplification circuit 2.
It is not always necessary to include an integra.tor 7 in the feed.back circuit and Figure 2 shows an example in ~hich this integrator is not included in the loop.
A specific advantage achieved by the afore-mentioned circuits is that the tolerance field of the frequencies of the oscillator 1 and the tuned circuit is increased. Moreover, possible variations i.n the loss resistances of the transmitter coil or temperature variations of the capacitor C of the tuned ci.r-cuit have no influence on the amplitude of the field generated by the transmitter coil 5. By rectifying the receiver signal the detector means is also insensi-tive to phase shifts in the coils and the driver unit 4. The amplitude of the electromagnetic field can easily be controlled by means of the direct reference voltage Uref-
Metallic object detection means of this type may for instance be used in apparatus for detecting metallic objects in earth in connection with geophysical prospecting but can also be used in electromagnetic proximity fuses for initiating the charge of a charge carrier, for instance a missile, pro-jectile, shell or the like, when this passes a metallic object at a certain dis-tance. In both of said applications, signal processing means are arranged to emit an active output signal in dependence on the interEerence electromotive force induced in the receiver coil due to the metallic object.
In Swedish patent No. 77.06158-8, which issued on April 30, 1981 to Aktiebolaget ~ofors, metallic object detector means of the afore-mentioned type are illustrated and used in an electromagnetic proximity fuse for initiating the charge of a charge carrier when a metallic object is located at a well de-fined distance from the charge carrier, preferably a small distance of 0.5 -1.5 m. The advantage of generating an electromagnetic field for use in a proxi-mity fuse is that such fuse acts independently of the earth-magnetic field and also independently of whether or not the target is built up of iron in contrast to previously known magnetic proximity fuses.
The proximity fuse according to said Swedish patent specification is mainly characterized in that the receiver coil is located in front of and at a certain distance from the transmitter coil, preferably in the nose section of the charge carrier, so that in addition to the interference electromotive force ~/ -- 1 --A ~
also an electromotive force is induced in the receiver coil under direct influ-ence of the electromagnetic field generated by the transmitter coil and that the signal processing means are arranged to separate the interference electro-motive force from the directly induced electromotive force and to emit the active output signal to means for initiating the charge.
In geophysical prospecting as well as in proximity fuses it is desired to keep the amplitude of the generated electromagnetic field constant, i.e., independent of frequency, temperature, and different disturbing factors which may affect the detector means. I~ is therefore desired to design the trans-mitter unit in such a way that the requirement of a constant amplitude of the field can be better fulfilled than previously. This also represents an advan-tage with respect to the manufacturing of the detector means as the tolerance requirements of for instance the transmitter coil can be reduced It is therefore an object of the present invention to provide detector means in which the amplitude of the ele~r, ~gn~tic field gencrated by the tra[ls-mitter coil can be easily kept constant. The invention is characterized by an oscillator for generating a sinusoidal signal for the transmitter coil, means ~or controlling the amplitude of the sinusoidal signal, a feed-back circuit com-prising means for rectifying a signal emitted by the coil system and means for comparing said rectified signal with a reference voltage and in dependence of '` L~ said comparison-3*~ an output signal to said means for controlling the ampli-tude of the sinusoidal signal. In one embodiment it is the signal emitted by the receiver coil due to the directly induced electromotive force in the coil which is fed back but in a second embodiment it is a signal emitted by the transmitter coil which is fed back.
The invention will now be described in more detail with reference to the accompanying drawings in which:
Figure 1 is a block diagram of a first embodiment of the invention;
and Figure 2 i5 a block diagram of a second embodiment of the inven~ion.
The block diagram of Figure l illustrates the basic structure and function of the detector means according to the invention. The detector means may for instance be utili~ed in a metal detector for geophysical prospecting or in a proximity fuse for initiating a charge near a metallic object (the target).
Both of said applications include a coil system which comprises a transmitter unit in the form of a transmitter coil for generating an electromagne~ic field which is distributed in space according to known physical laws and a receiver unit in the form of a receiver coil which is located so that it is affected by the electromagnetic field generated by the metallic object in which case an in-terference electromotive force is induced in the coil. The recciver coil is also ~ocated in such a way that a part of the electromagnetic field, generated by the transmitter coil, falls directly on the receiver coil and gives r;se to a direct-ly induced electromotive force in ~he coil. By means of signal processing means the interference electromotive force is then separated from the directly induced electromotive force and an active output signal is provided in dependence of the interference electromo$ive force only.
The signal processing of the interference electromotive force is not a part of this invention and is therefoTe not described here. Reference should be made to the above-mentioned Swedish patent specification No. 77.06158-8 if more information is re~uired regarding the signal processing aspect. The present invention relates to the transmitter unit of the detector means and includes a feed-back circuit which makes it possible to keep the amplitude of the electro-magnetic field generated by -the tr~nsmitter coil constant.
More particularly, the block diagram illustrated in Figure l comprises an oscillator 1 for generating a sinusoidal signal X oE a specific freqwency and amplitude. Signal X is fed via one input of a variable attenuation/amplification circuit 2 to a tuned circuit comprising a current feed back amplifier 3, a capa citor C, a driver unit 4 and a transmitter coil 5. The amplifier 3 and the driver unit ~ provide the necessary current I for the transmitter coil 5. The transmitter coil then generates an electromagne-tic field with the same frequency as the sinusoidal signal X. This field is distributed in space according to known physical laws and a part of the field falls directly on a receiver coil 6 located close to the transmitter coil 5 or at a certain distance from said coil, depending on the field of application. An electromotive force is then induced in the receiver coil 6 and gives rise to a receiver signal Im which is fed to an integrator 7 and a rectifier 8 in which the signal is integrated and rectified, respectively. The signal is then compared with a reference voLtage, Uref in a comparator 10, and if the sum of the rectified signal and the reference voltage is not equal to zero, then an error signal is obtained which is integrated by means of an integrator 9 to give rise to a signal Y, which is fed to the other input of the variable attenuation/amplification circuit 2 to control the output of circuit 2 according to the values of the sinusoidal signal X and the integrat-ed error signal Y.
The block diagram illustrated in Figure 2 is similar to that of Figure 1 but in this second embodiment the receiver coil is not used in the invention.
Instead, the transmitter coil voltage signal Is is fed back and rectified by the rectifier 8, the rectified signal then being fed to comparator 10 as before.
Specifically, the feed-back circuit is connected to the terminal 11 at the junc-tion of the capacitor C and the transmitter coil 5 in the tuned circuit.
Another difference between the first and second embodiments relates to the variable attenuation/amplification circuit 2. In the second embodiment _ 4 --~ 3~
this circuit is connected to oscillator 1 in an oscillator feed-back configura-tion circuit, but as with the first embodi.ment the integrated error signal Y is also used here to control the variable attenuation/amplification circuit 2.
It is not always necessary to include an integra.tor 7 in the feed.back circuit and Figure 2 shows an example in ~hich this integrator is not included in the loop.
A specific advantage achieved by the afore-mentioned circuits is that the tolerance field of the frequencies of the oscillator 1 and the tuned circuit is increased. Moreover, possible variations i.n the loss resistances of the transmitter coil or temperature variations of the capacitor C of the tuned ci.r-cuit have no influence on the amplitude of the field generated by the transmitter coil 5. By rectifying the receiver signal the detector means is also insensi-tive to phase shifts in the coils and the driver unit 4. The amplitude of the electromagnetic field can easily be controlled by means of the direct reference voltage Uref-
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Metallic object detection means comprising a coil system with a trans-mitter coil for generating an electromagnetic field and a receiver coil which is arranged in such a way that an electromotive force is induced in the coil when the coil is affected by the field generated by a metallic object and the field generated directly by the transmitter coil and wherein the amplitude of the electromagnetic field generated by the transmitter coil is kept constant charac-terized by an oscillator for generating a sinusoidal signal for the transmitter coil, means for controlling the amplitude of the sinusoidal signal, a feed-back circuit comprising means for rectifying a signal emitted by the coil system and means for comparing said rectified signal with a reference voltage and in de-pendence of said comparison emmitting an output signal to said means for controlling the amplitude of the sinusoidal signal.
2. Means according to claim 1 characterized by an integrator and a recti-fier for integrating and rectifying, respectively, the signal emitted by the coil system.
3. Means according to claim 2 characterized by a further integrator for integrating the signal emitted by the comparison means.
4. Means according to claim 1 characterized in that said signal emitted by the sensor device comprises the signal emitted by the receiver coil due to the directly induced electromotive force in the coil.
5. Means according to claim 1 characterized in that said signal emitted by the sensor device comprises a signal emitted by the transmitter coil.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8102827A SE426269B (en) | 1981-05-06 | 1981-05-06 | DEVICE FOR THE DETECTION OF METAL FORMS |
| SE81.02827-6 | 1981-05-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198165A true CA1198165A (en) | 1985-12-17 |
Family
ID=20343740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000402340A Expired CA1198165A (en) | 1981-05-06 | 1982-05-05 | Means for metallic object detection |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS57192887A (en) |
| BE (1) | BE893088A (en) |
| CA (1) | CA1198165A (en) |
| CH (1) | CH656231A5 (en) |
| DE (1) | DE3217033A1 (en) |
| FR (1) | FR2505508B1 (en) |
| GB (1) | GB2097933B (en) |
| IT (1) | IT1147941B (en) |
| NL (1) | NL8201811A (en) |
| NO (1) | NO821485L (en) |
| SE (1) | SE426269B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5423262A (en) * | 1992-11-04 | 1995-06-13 | Bofors Ab | Magnetic proximity fuse |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59141001A (en) * | 1983-02-01 | 1984-08-13 | Mitsubishi Electric Corp | Detecting method for effective end position of metallic pipe |
| US5426363A (en) * | 1993-04-26 | 1995-06-20 | Kabushiki Kaisha Honda Denshi Giken | Object detecting device |
| AU2009262370B2 (en) * | 2008-06-27 | 2014-11-27 | Minelab Electronics Pty Limited | Constant current metal detector with driven transmit coil |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB835128A (en) * | 1955-09-17 | 1960-05-18 | Asea Ab | Apparatus for examining a substance utilising the effect of the substance on the q factor of a resonant circuit |
| DE2052989C3 (en) * | 1970-10-30 | 1973-11-08 | Guenther Dipl.-Ing. 2209 Sushoern Weber | Switching device triggered by one or more moving objects |
| GB1448877A (en) * | 1973-09-04 | 1976-09-08 | Weber G | Electronic switching device for sensing a body and for converting such sensing into an electrical signal |
| GB1561641A (en) * | 1976-08-05 | 1980-02-27 | Redland Automation Ltd | Presence detector apparatus |
| LU75628A1 (en) * | 1976-08-19 | 1978-04-13 | ||
| DE2722511A1 (en) * | 1977-05-18 | 1978-11-30 | Voll Walter | METAL DETECTOR |
| DE2722498C3 (en) * | 1977-05-18 | 1982-02-04 | Walter Ing.(Grad.) 8728 Hassfurt Voll | Device on a motor vehicle for displaying a minimum distance |
-
1981
- 1981-05-06 SE SE8102827A patent/SE426269B/en not_active IP Right Cessation
-
1982
- 1982-04-22 GB GB8211642A patent/GB2097933B/en not_active Expired
- 1982-05-03 NL NL8201811A patent/NL8201811A/en not_active Application Discontinuation
- 1982-05-04 JP JP57075053A patent/JPS57192887A/en active Pending
- 1982-05-05 FR FR8207818A patent/FR2505508B1/en not_active Expired
- 1982-05-05 CH CH2774/82A patent/CH656231A5/en not_active IP Right Cessation
- 1982-05-05 IT IT48333/82A patent/IT1147941B/en active
- 1982-05-05 NO NO821485A patent/NO821485L/en unknown
- 1982-05-05 CA CA000402340A patent/CA1198165A/en not_active Expired
- 1982-05-06 DE DE19823217033 patent/DE3217033A1/en active Granted
- 1982-05-06 BE BE0/208015A patent/BE893088A/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5423262A (en) * | 1992-11-04 | 1995-06-13 | Bofors Ab | Magnetic proximity fuse |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2097933A (en) | 1982-11-10 |
| NL8201811A (en) | 1982-12-01 |
| IT8248333A0 (en) | 1982-05-05 |
| SE8102827L (en) | 1982-11-07 |
| IT1147941B (en) | 1986-11-26 |
| FR2505508A1 (en) | 1982-11-12 |
| DE3217033A1 (en) | 1982-11-25 |
| JPS57192887A (en) | 1982-11-27 |
| CH656231A5 (en) | 1986-06-13 |
| NO821485L (en) | 1982-11-08 |
| FR2505508B1 (en) | 1985-11-29 |
| BE893088A (en) | 1982-08-30 |
| DE3217033C2 (en) | 1991-01-03 |
| GB2097933B (en) | 1985-05-15 |
| SE426269B (en) | 1982-12-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |