09 - Scientific and electric apparatus and instruments
Goods & Services
Electronic detectors for observing and measuring the infrared spectrum using thermographic or infrared technology for screening for variances in body temperature other than for medical use
09 - Scientific and electric apparatus and instruments
Goods & Services
Electronic detectors for observing and measuring the infrared spectrum using thermographic or infrared technology for screening for variances in body temperature other than for medical use
09 - Scientific and electric apparatus and instruments
Goods & Services
Electronic detectors for observing and measuring the infrared spectrum using thermographic or infrared technology for screening for variances in body temperature other than for medical use
Remanent ground response is induced by rapid high current in a transmit coil. The transmit coil remains at zero current for a sufficient time for the remanent ground response to be sensed in a receive coil. A rapid high voltage and a sustained low voltage establish and maintain a stable current in the transmit coil followed by a zero current period. The sequence is repeated with a stable negative and followed by positive currents and a zero current. The receive coil is repeatedly interrogated at zero current between switch closings connecting in the transmit coil. Combined ground remanence and target eddy current signals are received during the constant current periods, and the ground remanence signals sensed during zero transmit coil current are subtracted from the combined signals.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
G01V 3/12 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with electromagnetic waves
G01V 3/40 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation specially adapted for measuring magnetic field characteristics of the earth
G01V 3/15 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation specially adapted for use during transport, e.g. by a person, vehicle or boat
17.
Auto nulling of induction balance metal detector coils
A metal detector has a large primary transmit coil, a small primary feedback bucking coil, a first receive coil, and a second receive coil. A variable resistance device is connected to the first and second receive coils. A voltage source is connected to the large primary transmit coil. The voltage source is oppositely connected to the small primary feedback bucking coil. A primary voltage is provided to the large primary transmit coil. A reverse primary voltage is provided to the small primary feedback bucking coil. The small primary feedback bucking coil is positioned near the first and the second receive coils. The metal detection methods and apparatus sums up the signals from the two secondary coils. One is over nulled, the other is under nulled. They are close enough to an inductive null to attenuate the stray coupled signals from the primary driving signal and detecting the object.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
G01V 3/38 - Processing data, e.g. for analysis, for interpretation or for correction
A ground search metal detector with a pivotally mounted search coil that locates a stem connector at either of a storage position or an operational position. The operational position locates the connector adjacent to the central portion of the search coil to facilitate useful operational characteristics, and the storage position locates the connector adjacent to the perimeter edge to facilitate compact storage of the metal detector by pivoting the stem to overlap the search coil.
G01V 3/165 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation specially adapted for use during transport, e.g. by a person, vehicle or boat operating with magnetic or electric fields produced or modified by the object or by the detecting device
A hermetically sealed metal detector includes a plastic housing with an integrally formed diaphragm having a predetermined area and a thickness that enables vibration thereof by an internal acoustic transducer. An alert signal audibly drives the transducer in response to a metal detector circuit. The acoustic transducer is positioned to align the transducer output port adjacent to the interior surface of the diaphragm, which enables coupling of the acoustic signal through an air gap to vibrate the diaphragm. A cover is disposed about the diaphragm on the exterior of the housing. The cover has a vent formed therethrough for enabling passage of the acoustic energy to the exterior of the housing. Light and battery hermetic sealing are also presented.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
G01V 3/17 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation specially adapted for use during transport, e.g. by a person, vehicle or boat operating with electromagnetic waves
A01B 1/20 - Combinations of different kinds of hand tools
A hermetically sealed metal detector includes a plastic housing with an integrally formed diaphragm having a predetermined area and a thickness that enables vibration thereof by an internal acoustic transducer. An alert signal audibly drives the transducer in response to a metal detector circuit. The acoustic transducer is positioned to align the transducer output port adjacent to the interior surface of the diaphragm, which enables coupling of the acoustic signal through an air gap to vibrate the diaphragm. A cover is disposed about the diaphragm on the exterior of the housing. The cover has a vent formed therethrough for enabling passage of the acoustic energy to the exterior of the housing. Light and battery hermetic sealing are also presented.
G08B 3/00 - Audible signalling systemsAudible personal calling systems
G08B 5/00 - Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied
G08B 7/00 - Signalling systems according to more than one of groups Personal calling systems according to more than one of groups
G01D 5/12 - Mechanical means for transferring the output of a sensing memberMeans for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for convertingTransducers not specially adapted for a specific variable using electric or magnetic means
This invention relates to a metal detector where a coil is used to transmit a periodic magnetic field to energize metal objects that are concealed and often buried or hidden in a matrix (ground) containing ferromagnetic minerals. There are many difficult and often simultaneous challenges, such as detecting large deep targets, detecting minutely small targets, identifying target properties, ignoring the ferromagnetic matrix, avoiding a net magnetic field which can trigger magnetic sensors in land mines, and ignoring conductive salt responses. Either time-domain or frequency domain methods have been used to address these challenges with mixed levels of success. The ability to simultaneously use time-domain and frequency-domain methods can expand detection capability. Techniques are presented for achieving these goals.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
A constant current is provided to an energizing coil in a magnetic detector by charging a capacitor through a resistor from a high voltage source. Discharging of the capacitor into the energizing coil quickly increases current in the energizing coil. After the capacitor is switched off, a low voltage source maintains current constant in the energizing coil. The coil discharges its energy as a negative voltage to the capacitor. A high negative voltage source tops off the capacitor. After a delay, the capacitor discharges a negative current into the energizing coil. A negative low voltage source maintains the negative current. The negative voltage source is disconnected, and the coil discharges positive voltage into the capacitor. The high voltage source tops off the capacitor with positive voltage to repeat the cycle.
G01N 27/72 - Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
G01N 27/80 - Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating mechanical hardness, e.g. by investigating saturation or remanence of ferromagnetic material
26.
Time domain method and apparatus for metal detectors
This invention provides a pulse induction metal detector where a coil transmits a pulsed magnetic field to energize metal objects that are often buried or hidden in a matrix (ground) containing ferromagnetic minerals. A difficult challenge is to detect and identify the metal object while ignoring the ferromagnetic matrix. Techniques are presented for achieving this.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
A new hybrid metal detector combines induction balance and pulse induction technologies. Target signals are generated from a transmitted wave that has both induction balance and pulse current inducing characteristics and uses pertinent sampling of the receive data. Combining the two data sources provides eddy current target identification while excluding ground permeability and remanence obscuration.
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
30.
Dual field search coil for pulse induction metal detectors
A new dual field search coil for pulse induction metal detectors has multiple coplanar wire coils of different diameters connected in series with the output of a pulse source, overcoming the loss of target size resolution associated with a single coil search loop. Small objects are sensed by an internal small coil and larger objects are sensed by the larger outside coil, and the overall depth of target sensing remains similar to that of a single coil construction. The smaller coil is isolated from the pulse source by the inductance of the larger coil and will ring at a frequency determined by its own parameters. To prevent the smaller coil from ringing, a second damping resistor is connected across the terminals of the smaller coil at the junction of the large and small coils making up the modified search loop.
G01N 27/72 - Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
G01V 3/08 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
A hand-held metal detector and soil excavation device useful for locating and retrieving metallic objects concealed in soil or other materials. The device includes a housing with a hand-grip portion and an elongated probe portion. There is an excavation tool connected to the housing that is useful for moving soil to locate metallic objects that are sought. The device also includes a metal detector circuit located within the housing, that operates to generate an alert signal when the probe portion is moved into proximity of metallic objects.
Metal detectors include a sense coil coupled to an analog to digital converter that produces a numeric representation of an electrical signal associated with a conductive object situated in an active region of a sense coil. The numeric representation is processed to obtain a noise contribution associated with random noise, fixed pattern noise, and/or thermal drift. The noise is subtracted from the numeric representation to produce a numeric difference. The numeric difference includes contributions associated with conductive objects located in a sense volume defined by the sense coil. The numeric difference (or the numeric representation) can be digitally processed with, for example, a matched filter to enhance the conductive object contribution. The matched filter can be based on a measured sense coil speed or can be based on typical sense coil speeds.
G01V 3/08 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
G01V 3/10 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
