Abstract: A device for finding studs in a wall that uses a strong magnet mounted in a pen-like holder. The device is slid along a wall until a fastener is detected. The magnet is strong enough to provide firm pull on the fastener providing a sure response to the stud. The magnet is also strong enough to hold the device securely to the wall so that it projects out orthogonally from the wall surface. The device can then be left in place, with no need to mark the location of the stud on the wall. Moreover, the device can be left in place while additional studs are located using the device as a reference and a tape measure to measure standard stud spacing in the wall. In this way, one or more studs may be quickly and surely located.

Abstract: The invention offers a position determining method that ensures high reliability in the determination of a digging position by sensing on the ground an AC magnetic field generated by a coil housed in a digging head, even in the presence of a noise magnetic field affecting the position determination. This is a digging position determining method in a non-open-cut method of excavation which senses the AC magnetic field provided from a magnetic field source by an above-ground magnetic sensor to calculate the position of the magnetic field source from the magnitude and direction of the sensed AC magnetic field.

Abstract: To locate via electromagnetic signaling each of a plurality of buried side leg conveyances (141-146) coupled to a common underground backbone conveyance (12), a cable locating signal generator (17) applies a plurality of different frequency conveyance locating signals to the backbone conveyance. A separate one of a plurality of filter arrestors (181-186) selective passes a particular one of the plurality of different frequency locating signals onto a corresponding one of the side leg conveyances. In this way, each side leg conveyance carries only a particular frequency locating signal whose strength remains unaffected by the locating signal on the other side leg conveyances.

Abstract: An apparatus for locating a target object using parametric inversion employs a signal injector capable of injecting a signal into the target object, wherein at least a portion of the target object is buried, a magnetic field receiver, a matching processor for matching to a magnetic field received by the magnetic field receiver a parametric magnetic field distribution model corresponding to the target object and at least one other object, and a locating processor for locating the target object using parameters from the parametric magnetic field distribution model.

Abstract: A device for locating a metallic stud disposed within a wall. The device comprises an elongate housing which itself comprises a base portion defining a generally planar contact surface and a handle portion which extends from the base portion. In addition to the housing, the device comprises at least one magnet which defines a generally planar attraction surface. The magnet is disposed within the base portion of the housing such that the attraction surface extends in generally parallel relation to the contact surface. The magnet and the housing are sized relative to each other such that the force of magnetic attraction between the magnet and the stud when the device is oriented in a particular location upon the wall is sufficient to maintain the device thereon without external support.

Abstract: A display apparatus of magnetic flux density for detecting an internal crack of a metal or a shape of the metal includes a three-dimensional magnetic flux focusing unit installed near the metal, for concentrating magnetic flux generated by the metal, a magnetic flux density measurement unit installed near the magnetic flux focusing unit, for measuring changes in magnetic flux density concentrated by the magnetic flux focusing unit, and a display unit electrically connected with the magnetic flux measurement unit, for real-time displaying and storing changes in the magnetic flux density.

Abstract: A transmitter that is electrically connected to a circuit and an associated receiver is used to identify an element of that circuit in the presence of other circuits. This may be used in AC or DC systems that are powered or not to identify or trace circuit elements such as lines, junctions, switches, fuses, or breakers. One version that identifies the circuit breaker of the circuit connected to the transmitter in a powered AC distribution system.

Abstract: Cathodic protection voltages are used to resist the damage to pipes or cables from electrolytic effects. However, localised fields can lead to stray currents and may result in corrosion and it is therefore desirable to detect and analyse those stray currents. Frequently there are several pipes in the area of interest and so it is necessary to distinguish between those pipes. Therefore the cathodic voltage on the pipes is modulated, with different pipes having different modulations. This modulation may be applied using an interrupter. Orthogonal modulations with non-unitary aspect ratios improve the discrimination between the pipes whilst maximising the energy content of the modulation pattern. The analysis is improved when the interrupters are synchronised with each other and so repeating on the same time-base. This synchronisation may be achieved using an external time signal such as GPS. An interrupter which can be used in this regard is also proposed, and may be powered from the cathodic voltage itself.

Abstract: A housing for a subsurface object locator has a bubble level vial for leveling surfaces using the housing and a scribe tip for marking a surface being probed with the locator.

Abstract: A detector to detect metal fragments (especially in pre MRI scanning) comprising: a first loop of conducting material, means to feed an rf signal to the first loop, a second loop of conducting material, and means to detect an induced rf signal consequent to said rf signal in said first loop, said second loop being geometrically symmetrically arranged with said first loop such that the rf signal, induced is therein is substantially zero when there are no metal fragments in the close proximity of the sensor. Preferably the second loop comprises two halves arranged in anti-phase, such in the form of a figure of eight. The loops are arranged to be substantially co-planar, such as on a PCB.

Abstract: An apparatus is provided for testing a communications line. The apparatus comprises a spool having at least eight terminals, and a length of wire wound on the spool. The wire has at least four subpairs of wires, each of which has opposite ends. A first end of each of the subpairs of wires is electrically connectable to the communications line, and a second end of each of the subpairs of wires is electrically connected to a corresponding terminal on the spool.

Abstract: A method for locating a device producing a magnetic field in a blind or inaccessible position of a work piece. A magnet is initially placed on a first side of the work piece such that a magnetic field produced by the magnet extends through the work piece. Probes are then positioned over a second surface of the work piece to determine the location of the axis of the magnet via the strength of the sensed magnetic field and the location where the strength measurements are made. Once the position of the axis of the magnet is determined, the work surface is either marked or worked on through the platform on which the probes are positioned. In particular, the present invention allows a very accurate positioning of a work tool on the second surface without the need to first visualize the first surface of the work piece.

Abstract: A vector positional display for use in an underground metal locating system for indicating the relative position of the underground metal with respect to a sensor array. The underground object functions as a RF transmitter, and the antenna array detects the transmitted signal. Commutation of the antenna array causes frequency modulation of the received signal which after demodulation can be used for identifying the direction of the object from the sensor array. A display slot counter accumulates count from a system clock, and resolution decoders determine field of view from the antenna array in locating the object. A zero crossing data probe triggers a display decoder which converts accumulated count to a format for energizing lights in the display unit.

Abstract: A system for locating underground or above ground metal and pipe objects includes a transmitter for generating an RF signal which is applied to the object which acts as a transmitter. An above-ground antenna array receives the RF signal transmitted by the underground object with a commutator for periodically and sequentially receiving signal from each antenna in the array, the commutator frequency modulating the received signal. A FM demodulator then demodulates the signal from the commutator and provides a Doppler effect frequency shift signal. A vector positional display then indicates position of the object based on the Doppler effect frequency shift signal relative to a reference signal.

Abstract: An excavator vehicle has sensors thereon at different heights. Each sensor may have a coil which is generally horizontal and which detects the magnetic field generated by a current in a buried conductor. By detecting the relative magnitudes of the component of the field parallel to the ground, as detected by the sensors, it is possible to determine whether or not the excavator vehicle is proximate the buried conductor. A warning may be generated, or the excavating tool of the excavator vehicle controlled, to prevent the excavating tool damaging the buried conductor.

Abstract: An apparatus for locating a target object using parametric inversion employs a signal injector capable of injecting a signal into the target object, wherein at least a portion of the target object is buried, a magnetic field receiver, a matching processor for matching to a magnetic field received by the magnetic field receiver a parametric magnetic field distribution model corresponding to the target object and at least one other object, and a locating processor for locating the target object using parameters from the parametric magnetic field distribution model.

Abstract: An article identification device 4 is mounted on a trap of which operation is diagnosed. The identification device 4 includes a memory 47 in which trap identification data is stored. When the identification device 4 receives an electromagnetic wave from a trap operation diagnosing device, a rectifier 46 derives DC power from the electromagnetic wave, which DC power drives the memory 47 and a modulator 48 so that an electromagnetic wave containing the trap identification data can be sent to the operation diagnosing device. The operation diagnosing device derives the trap identification data from the received electromagnetic wave to identify the trap whose operation the operation diagnosing device diagnoses.

Abstract: A system and method to locate electronic marker balls includes receiving a signal representative of a detected marker ball. The signal includes the resolved in-phase and quadrature-phase (I and Q) components, each centered about a first frequency. The I and Q components are filtered in order to shift the first frequency to a second frequency and match the second frequency I and Q components to exponential decay characteristics associated with the marker balls. The second frequency I and Q components phase integrated in order to distinguish the components from noise. The integrating is based upon predetermined gain coefficients and produces integrated I and Q components in accordance with the predetermined gain coefficients. Next, a magnitude of the integrated I and Q components is determined to produce an I and Q magnitude vector and a noise variance associated with the magnitude vector is determined. Finally, the recursive coefficients are adjusted in accordance with the determined noise variance.

Abstract: The present invention is directed to a non-contact detector for sensing a periodically varying magnetic field. The non-contact detector includes a probe having at least one magnetic sensor used to sense a magnetic environment generated by current running through a conductor. The detector includes means for periodically varying the magnetic environment and sensing means that is associated with each magnetic sensor that produces an electrical signal representative of the change in the magnetic environment. The detector also includes means for delivering a usable representation to a user in response to the sensing of the periodically varying magnetic environment.

Abstract: A hand held subsurface object locator has a pocket sized housing that contains circuitry and a power source for electrically detecting substratum objects hidden behind a surface. The housing is preferably less than two inches wide and at least three times as long as it is wide. The housing has a pocket clip preferably affixed to a battery compartment door at one end of the housing and the other end of the housing is tapered and includes a plurality of tapered indicators.

Abstract: A terminator unit for use in wiring networks for naming wiring outlets, for verifying the normality of the wiring and for avoiding antenna effect, comprising a connector having a plurality of contacts, a first set and a second set of plurality of resistors. The resistors of the first set are connected each between one common point and a selected contact, such that a particular binary code is determined according to the particular combination of resistors connected to selected contacts. The resistors of the second set, suitable for avoiding antenna effect, are connected between one common point and each of the contacts. When the connector is joined to a matching outlet of the wiring, the particular binary code is remotely recognized through the wiring by sensing the resistors and the continuity of the wiring and the absence of short circuits are verified by measuring the resistors of the second set.

Abstract: A dc connection (CAB1, CAB2) in a bipolar 12-pulse system for transmission of electrical energy by means of high-voltage direct current interconnects two converters, each one having two 6-pulse valve bridges (BR11, BR12, BR21, BR22) connected in series at a connection point (J1, J2). In a method for location of the cable, said cable is located by sensing of a magnetic field associated with a current flowing through the cable. The dc connection is temporarily supplied with a ground-mode current, intended for the location, and a magnetic field associated with said ground-mode current is sensed.

Abstract: A device for locating a metallic stud disposed within a wall. The device comprises an elongate housing which itself comprises a base portion defining a generally planar contact surface and a handle portion which extends from the base portion. In addition to the housing, the device comprises at least one magnet which defines a generally planar attraction surface. The magnet is disposed within the base portion of the housing such that the attraction surface extends in generally parallel relation to the contact surface. The magnet and the housing are sized relative to each other such that the force of magnetic attraction between the magnet and the stud when the device is oriented in a particular location upon the wall is sufficient to maintain the device thereon without external support.

Abstract: An inductive sensor arrangement for detecting ferromagnetic or non-ferrous electrically conducting objects hidden in a surrounding medium comprising three field coils arranged in essentially the same geometric plane and adjacently positioned at angular distances of usually 120° from each other around a central axis orthogonal to the plane for generating an alternating magnetic flux by a sequential excitation with an AC-current ramp. The sensor arrangement further comprises three sense coils respectively mounted inside each associated field coil and in an orientation to the axes of each of the field coils such that essentially no voltage is induced in the sensor coils in an environment free of a metallic object.

Abstract: A metal locating system includes a first transmitter unit and a second receiver detector unit for locating an under and above ground radio frequency driven element such as a pipe. The first unit is a radio frequency transmitter operating at radio frequencies and coupled to the driven element as a loss line antenna. The receiver second unit is a switched diversity antenna connected to a radio FM receiver and a differential phase detection system. When the first unit is driven by the driven element, the second unit is able to detect and trace the position of the driven element relative to the switched diversity antenna.

Abstract: A method of electronically isolating a conductor by sensing a current signal in the conductor, adjusting the current signal to yield an adjusted signal, and applying the adjusted signal to the conductor to oppose the current signal. Amplifying the signal, as well as phase-shifting the signal may adjust the current signal. The current signal may be sensed using magnetic induction, and the adjusted signal applied to the conductor using magnetic induction as well. The method is carried out using a clamping device that can further evaluate an environment of the conductor, by randomly changing a magnitude and phase of a test signal applied to the conductor, and examining a received signal in response to the changes. A tracking error in the adjusted signal can be handled by predicting a next required phase shift. Prediction coefficients can be calculated utilizing a least means square algorithm. The invention is particularly applicable to the location of obscured (e.g.

Abstract: A novel insert assembly for use in snowboards and other sporting equipment provides for embedded insert location, regardless of the properties of the insert material per se, and without requiring either expensive equipment or a complex location process. This is achieved by positioning a small inexpensive magnet on or within the insert cavity, or placing a plug-like magnet in the open threaded end of the inserts. After the board assembly is complete, a magnetic material such as iron powder is dusted on the surface of the board to react with the field lines created about each insert, revealing the insert location. Then, the board can be drilled to pierce the insert cap, and facilitate removal of any plug in the insert. It is also possible to provide, through powdered metal technology, an insert material which itself will produce the desired magnetic field of sufficient intensity at the dusted surface of the board.

Abstract: A housing for a subsurface object locator has a bubble level vial for leveling surfaces using the housing and a scribe tip for marking a surface being probed with the locator.

Abstract: An apparatus for finding studs within walls has an elongated magnet having a round and smooth outer surface. The magnet is attached at one of its ends to a bead chain wherein each of he beads is able to rotate relative to the next so that the magnet is essentially free of any restriction in rotating about its long axis with respect to the chain. In use, the magnet is held suspended from the bead chain and moved across a wall until it detects a metal object within the wall. The magnet then rotates against the wall until it places itself at the center of the object thus defining the center of a stud or other hidden object.

Abstract: A portable electronic reference point locator facilitates location of a reference point, located on one side of a structure (such as a wall, floor or ceiling), from the opposite side of the structure. The system is particularly useful when installing new electrical wiring or hardware, when installing new plumbing, or when performing other construction related tasks that require the location of one side of a structure to be determined relative to the other side of the structure. The system comprises a transmitter and a receiver. The transmitter is located at a position that defines the reference point, and includes an oscillator and an antenna that cooperate to generate and transmit an electromagnetic signal. The receiver includes a transducer that senses the electromagnetic signal transmitted by the transmitter, and an indicator that indicates whether the receiver is within a given distance of the transmitter.

Abstract: The invention provides an interactive means to locate and identify underground utilities. The apparatus is used with a marker associated with an elongate electrical conductor, which may be a cable shield or a trace wire. It includes a remote, portable probe that is used to transmit a RF signal to be received by a transponder associated with the marker. The transponder is powered by a DC potential on the conductor. In preferred embodiments it has the capability of communicating with a terminal unit over the conductor to transmit information and instructions between the probe and the terminal unit.

Abstract: A signal injecting apparatus which includes a microcontroller for generating a 1024 hertz square wave signal which is supplied through a NAND gate to a field effect transistor. When the transistor is switch on a tank circuit comprising a pair of capacitors and the primary of a signal injector coil starts oscillating and will continue to oscillate when the transistor is switch off. The power level for the signal to the cable is determined by an operator based on the operator inputs from depressing a pair of push button switches. The microcontroller, responsive to the operator inputs from the push button switches, outputs a digital word to a digital-to-analog converter that represents the required power level. The analog output signal from the digital-to-analog converter is supplied to a control loop circuit which adjust the power level by enabling and disabling the NAND gate.

Abstract: A line locating device and method that is capable of determining the location of a line even when a significant amount of transmitted signal is coupled to neighboring lines. A device according to this invention includes a transmitter that couples a transmitted signal onto a metal line where the transmitted signal is a first signal having a carrier frequency modulated with second signal of a lower frequency. The device also includes a receiver that receives a received signal from the metal line and evaluates the signal in terms of period and polarity to determine an incoming signal or an outgoing signal. The receiver addresses an appropriate signaling unit in response to the incoming signal or the outgoing signal.

Abstract: An electromagnetic wave isolation apparatus is provided for use in household multi-outlets, which apparatus includes an electromagnetic wave detecting circuit for sensing induced electromagnetic waves generated in the home or office and generating an output signal responsive to a predetermined level of the induced electromagnetic waves. An electromagnetic wave isolation circuit is provided, in response to the output signal of the detecting circuit to generate an output signal for driving a lamp which indicates the presence of electromagnetic waves and subsequently for driving a switch which enables one of AC output lines to be connected with the circuitry ground of the multi-outlet. A switching circuit is also included for activating a second switch provided in each of the AC output lines in response to the output signal of the isolation circuit. A resistor is connected between the circuitry ground and the ground terminal of the power cord of the multi-outlet.

Abstract: In a method and system for detecting a particular AC circuit from among a plurality of AC circuits at a circuit box, a transmitter is plugged into the particular AC circuit to be detected, the transmitter creating a high amplitude high-frequency current pulse. With a receiver, sensing the particular circuit at the circuit box by use of a sensing coil and employing a variable gain stage in conjunction with a threshold comparator and latch to pick off a signal caused by the high amplitude high frequency current pulse. The signal is latched so that a microprocessor can read the signal to activate an indication to a user when the particular AC circuit has been located at the circuit box. The microprocessor can be programmed after it is mounted into the receiver by use of a computer which transfers a program to the microprocessor. In an alternate embodiment of the invention, instead of the latch, the threshold comparator connects to an interrupt input of the microprocessor.

Abstract: A traceable push rod having a predetermined length comprising an inner layer, an intermediate layer and an outer layer. The inner layer characterized as being electrically conductive. The inner layer preferably made of copper or copper alloy. The intermediate layer characterized as being electrically insulative. The intermediate layer preferably at least partially made of fiber glass. The third layer characterized as being water proof. The third layer preferably made of plastic. The traceable push rod further having a first end and a second end. The first end having at least one sonde receiving terminal for removably receiving a sonde. The second end adapted for electrical communication with an electrical power source such as a battery or transmitter. The electrical power source adapted to provide an electric current to the inner layer and/or the sonde.

Abstract: The relative position of a cable (10) within a pipe (16) is obtained by first applying a locating signal to a metallic part (12) of the cable so that the locating signal radiates beyond the pipe. The strength of the locating signal is measured at two separate distances from the cable via a pair of signal detectors (24, 26). By comparing the difference in the locating signal strengths to a predicted differential locating signal strength for a given cable depth within a pipe of known parameters, the actual cable depth can be detected.

Abstract: An apparatus for locating positions on a surface of a structural member indicating the presence of elements within and below the surface of the structural member by means of a detector (1) including a scanning head (3), a position measuring device (4) and an evaluation unit (5) all located within a housing (2). A marking device (6) is connected to and interacts with the evaluation unit (5) for automatically placing a visible marking on the surface of the structural member at the location of the elements scanned by the detector.

Abstract: A nail locating device is adapted for locating a magnetically attractive nail that was driven into a non-magnetically attractive board, and includes a seat, an indicator rod and a biasing spring. The seat is adapted to be moved on a surface of the board, and confines a vertically extending receiving space therein. The indicator rod is disposed in the receiving space, and has a ball portion and a magnet supporting portion that extends downwardly from the ball portion. The magnet supporting portion has a magnet member mounted thereto. The biasing spring is disposed in the receiving space, and supports the ball portion of the indicator rod in the receiving space such that the indicator rod is pivotable in the seat and is movable downwardly in the receiving space due to attraction of the magnet member to the nail in order to indicate the location of the nail in the board.

Abstract: A system for detecting the orientation of an optical cable for communication purposes has resonant networks or transponders on or in the cable jacket or sheath which have electromagnetic field lines detachable at the surface and running in the direction of the cable. The system can be used for identification of the cable as well.

Abstract: A system for locating a circuit interrupter associated with a selected branch circuit. The system includes a passive transmitter that creates a current spike at a predetermined frequency and a receiver broadly tuned about that predetermined frequency. The current spike signal has a sufficiently short spike duration and a sufficient amplitude so as to substantially minimize development of a sympathetic signal on other branch circuits adjacent to the selected branch circuit. The passive transmitter includes a voltage controlled switch in series with a charge storage device. The receiver drives a user-perceivable signaling device upon sensing the current spike. Related subsystems and methods are also disclosed.

Abstract: A radio link is established between the portable receiver used by an operator to trace the underground portion of a utility and the transmitter which induces a magnetic signal in the utility. Circuitry in both transmitter and receiver allows the operator who is remote from the transmitter to interrogate the transmitter from the receiver for essential information and to control operating functions at the transmitter. Such operations as changing the transmission frequency of the generator, conserving batter power by switching the transmitter's frequency generator to and from a power saving standby mode during periods of non-use, checking on the power level of the battery, and determining if the transmission circuit is complete and unbroken can be effected without the necessity of the operator returning to the site of the transmitter.

Abstract: A service provider that buries multiple utility conveyances (12a. 12b and 12c) along a common right of way (14) may facilitate their location via a technician (24) by impressing a pulsed confirmation signal (23) on each conveyance in addition to a conventional locate signal (16). The pulsed confirmation signal is uniquely identifies that conveyance, but also contains information that identifies the total number of conveyances and their relationship with each other.

Abstract: Location of an underground utility conveyance having a metallic part (10) running along its length is enhanced by providing a plurality of selective conduction units (30) spaced along the length of the conveyance. Each selective conduction unit selectively shunts the metallic part of the conveyance to ground at a point between its first and second ends in response to a particular pattern of pulses modulated onto the locating tone impressed on the metallic part by a cable-locating signal generator (14) to cause only that portion of the metallic part lying between the first end and said point to radiate the locating signal. In this way, the amplitude of the locating signal radiated above the earth for locating purposes is increased.

Abstract: A buried closure guard has an electronic transponder attached to a flat, perforated carrier sheet constructed of a flexible polymer. Holes in the carrier sheet, which serve to anchor the guard, preferably have an effective diameter of at least about 1½″ to allow typical backfill materials to pass through. By providing a webbed carrier, any protrusion of a digging tool (such as teeth on a backhoe bucket) will catch on one of these holes and pull at the carrier to make it further visible during excavation. The perforated construction of the sheet allows backfill material to settle and pass through the carrier without significantly shifting or bending the carrier. The carrier also makes it easy to manually deploy the transponder, i.e., maintain a proper horizontal orientation of the transponder coil.

Abstract: A boring operation performed by a boring head (18) is controlled to avoid interference with an adjacent buried conveyance (20) by first locating the conveyance and thereafter establishing a safety zone (24) thereabout. After establishing the safety zone, a check is made along the border (24a) of the safety zone adjacent the intended bore path for the presence of a monitor signal radiated by the bore head. If the bore monitor signal is detected at the safety zone border, an alert is generated.

Abstract: A device for electronically marking a buried closure has a transponder and a shield or cover affixed to the transponder in such a manner that, when attached to the buried closure, the transponder is positioned at a predetermined location and orientation with respect to the known position and orientation of the buried closure. The shield can have a raised portion housing the transponder, and is preferably elongated with an arcuate cross-section, generally larger than the buried closure.

Abstract: A single-sensor measurement system for detection and location of an AC signal emanating from a concealed energized electric conductor. A calibration routine of a measurement process carried out by the instrument first determines the background signal level of the AC signal at an initial position of the instrument. A second AC signal level is measured at a second location. The second signal level is compared with the background signal level. A signal indicating the presence of the energized electric conductor is generated by the instrument when the comparison result is greater than or equal to a predetermined value. The instrument initially positioned directly over a concealed energized electric conductor is automatically re-calibrated when a decrease in the AC signal level of a predetermined amount is detected. The electric field sensor is directly printed on the inside bottom panel of the instrument case and over the raised portions formed on the inside bottom panel.

Abstract: A hidden object sensor is described which senses and locates hidden objects hidden behind a surface of an architectural structure. The sensor includes sensing elements for sensing live wires behind the accessible surface, and separate sensing elements for respectively sensing metal and non-metallic objects behind the tested surface. A microprocessor alternates between the use of the various sensing elements and their associated circuits to detect live wires, metal objects, or wood studs. Visible and audible indicators are provided for indicating the device's mode of operation and the locations of sensed hidden objects.

Abstract: A display in a portable detector unit (e.g., a handheld “stud sensor”) projects a pattern of light onto a surface beneath which a hidden object is located. The pattern represents the location of a sensed characteristic of the object with respect to the surface. The pattern may include a single line or a plurality of lines, and may be projected in one or more directions.