Abstract: A magnetic coupler for inducing a signal on a buried utility wire. The coupler has two elongated jaws, each extending along a separate longitudinal axis. The jaws are attached at a hinge. The jaws may be placed about an exposed portion of the utility wire. A signal generate provides a signal which is emitted from a transmitter in each of the jaws. The signals emitted from each jaw are antiphase to one another, such that they are additive to a utility wire disposed between the jaws but out of phase with respect to any utility not between the jaws. The signal is thus induced on the utility wire and can be detected as emitted from its below ground length by a conventional locator.

Abstract: A magnetic coupler for inducing a signal on a buried utility wire. The coupler has two elongated jaws, each extending along a separate longitudinal axis. The jaws are attached at a hinge. The jaws may be placed about an exposed portion of the utility wire. A signal generate provides a signal which is emitted from a transmitter in each of the jaws. The signals emitted from each jaw are antiphase to one another, such that they are additive to a utility wire disposed between the jaws but out of phase with respect to any utility not between the jaws. The signal is thus induced on the utility wire and can be detected as emitted from its below ground length by a conventional locator.

Abstract: A security system for controlling access to an enclosed conduit along which runs fiber optic cable, the conduit having a cover for access to the cable, the system having a communications receiver and a modulator responsive to an output of the receiver for coupling non-intrusively to the fiber optic cable adjacent the cover, the communications receiver being responsive to the presence or absence of an access authorization signal from an operator to cause the modulator to introduce a signal to the fiber optic cable indicative of the authorization status.

Abstract: A liquid level sensor for insertion into a tank for measuring the liquid level in the tank comprises an elongate tubular frame and a float movable inside the frame to seek the liquid level. A float lock guide formed as an elongate member is mounted lengthwise inside the frame. A float lock formed as an elongate member is located inside the frame parallel to the float lock guide. A plurality of linkages is pivotally connected between the float lock guide and the float lock such that lengthwise movement of the float relative to the float lock guide causes corresponding lateral movement of the float in the frame between an unlocked position where the float is free to move lengthwise in the frame to seek the liquid level and a locked position where frictional forces retain the float between the float lock and an inner wall portion of the frame.

Abstract: A liquid level measuring device includes an elongate handle and an elongate frame arranged in telescoping relationship. The frame is movable between a collapsed position for storage and an extended position for usage. A float is movable lengthwise along the elongate frame. A control rod extends lengthwise in the elongate frame and through a passage in the float. The control rod controls movement of the float relative to the elongate frame. An actuator actuates the control arm to move the float from the locked position to the unlocked position in response to a downward pressure between a lower end of the elongate frame and a bottom surface of the container so that the float is free to seek the liquid level in the container and to move the float from the unlocked position back to the locked position when the downward pressure is released.

Abstract: A liquid level sensor for measuring liquid levels in underground and above ground containers includes a frame formed to have an elongate hollow tubular configuration that encloses a cavity. A cam pivot has an end extending into the cavity from a first inner wall portion of the frame. A cam is arranged to be pivotal about the end of the cam pivot. A float is placed in the cavity. A spring is arranged to bias the cam arm into contact with the float to force a side portion of the float into a locked position in frictional engagement with the second inner wall portion of the frame. A cam actuator pivotally mounted in a lower end portion of the frame exerts a force on the cam arm to release the float from the locked position when the lower end of the frame contacts the container bottom.

Abstract: In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.

Abstract: A data sonde for use in horizontal drilling is provided, the data sonde comprising an antenna for emitting a first modulated signal from the data sonde, the first signal comprising zero and non-zero emission components in different periods, and a receiver for receiving an intermittent second data signal during first signal zero emission periods. A method of operation of the same is also provided.

Abstract: A liquid level measuring system includes a housing mounted to a container and a flexible coupling connected between the housing and a tubular frame suspended in a container holding a liquid. The flexible coupling maintains the tubular frame in a vertical orientation in the container. The tubular frame has a pair of 270° rifling grooves therein. A float is mounted in the tubular frame. The float has a pair of projections that extend from opposite sides portion thereof into the rifling grooves so that the float is force to rotate as it moves vertically in the tubular frame to seek the liquid level. A magnetic coupler assembly transfers movement of the float to an indicator. The magnetic coupler assembly includes a pair of facing dielectric discs. Each dielectric disc has three magnets mounted thereon with opposite poles facing one another.

Abstract: A system for actuating an indicator in response to a depth change in a liquid that is confined to a container comprises a housing, a float constrained to vertical movement in response to changes in liquid depth in the container, a drive rod arranged to rotate in response to vertical movement of the float, and a coupler mechanism mounted between the drive rod and arranged to transfer movement of the actuator to an indicator.

Abstract: In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.

Abstract: A float is arranged in a tubular frame to be unlocked to float in a liquid when the lower end of the frame contacts a bottom surface of a container containing the liquid. A float lock guide and a float lock actuator are mounted in the passage to move the float laterally in the frame as the lower end of the frame is moved away from the bottom surface of the container to lock the float in frictional engagement with the frame.

Abstract: A system for actuating an indicator in response to a depth change in a liquid that is confined to a container comprises a housing, a float constrained to vertical movement in response to changes in liquid depth in the container, an actuator connected to the housing and arranged to move in response to vertical movement of the float, and a coupler mechanism mounted between the actuator and the housing and arranged to transfer movement of the actuator to the indicator.

Abstract: A system for actuating an indicator in response to a depth change in a liquid that is confined to a container comprises a housing, a float constrained to vertical movement in response to changes in liquid depth in the container and an actuator arranged to move in response to vertical movement of the float. A flexible coupling is connected to the actuator and arranged to maintain the actuator in a vertical orientation in the liquid when the actuator and the housing are out of vertical alignment, and a coupler mechanism arranged to transfer movement of the actuator to the indicator.

Abstract: A liquid level measuring device includes an elongate handle and an elongate frame arranged in telescoping relationship. The frame is movable between a collapsed position for storage and an extended position for usage. A float is movable lengthwise along the elongate frame. A control rod extends lengthwise in the elongate frame and through a passage in the float. The control rod controls movement of the float relative to the elongate frame. An actuator actuates the control arm to move the float from the locked position to the unlocked position in response to a downward pressure between a lower end of the elongate frame and a bottom surface of the container so that the float is free to seek the liquid level in the container and to move the float from the unlocked position back to the locked position when the downward pressure is released.

Abstract: A device that can reduce the effects of interference on an electromagnetic field emitted from a buried, underground or otherwise inaccessible object is provided. The device generates quality metrics relating to a plurality of sideband signals from one or more input signals, compares the quality metrics and selects one or more sideband signals, dependent on the respective quality metrics. A method of selecting one of a plurality of sideband signals using quality metrics is also disclosed.

Abstract: In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.

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: In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.

Abstract: A monitoring device defines a boundary for movement of an underground object such as a booring tool. The underground object generates a magnetic field which is detected by the monitoring device. The monitoring device then determines the position of the underground object relative to itself, and hence to the boundary. The movement of the underground object can then be controlled so that it does not cross the boundary. The monitoring device may therefore define a protection zone so that a buried object within that protection zone will not be contacted by the moveable underground object.