Abstract: An accelerometer module is supported within an interior passage of a transmitter housing of a transmitter that is itself receivable within an inground housing of an inground tool to perform an inground operation which subjects the transmitter to mechanical shock and vibration. An accelerometer housing of the module includes an exterior periphery that is receivable in the interior passage of the transmitter. A resilient damping foam can be supported to dispose the foam between the accelerometer housing and the transmitter housing such that the foam cooperates with the accelerometer housing to form a complex mass-spring-damper system that exhibits a resonant frequency which is controllable. An accelerometer cartridge of the module can include a mass that is at least five times the mass of an original accelerometer cartridge. In one feature, the accelerometer cartridge can include a mass of at least 20 grams for a one inch diameter transmitter housing.

Abstract: A boring tool is movable through the ground. A transmitter supported by the boring tool transmits an electromagnetic homing signal. A portable device monitors the electromagnetic homing signal and receives the electromagnetic homing signal in a homing mode for guiding the boring tool to a target position. A processor generates steering commands for guiding the boring tool based on a bore plan in a steering mode such that at least some positional error is introduced without using the electromagnetic homing signal. Switching from the steering mode to the homing mode is based on monitoring of the electromagnetic homing signal as the boring tool approaches the portable device to then guide the boring tool to the target position location in compensation for the positional error. Intermediate target positions are described as well as guiding the boring tool based on the homing signal so long as the portable device receives the signal.

Abstract: A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.

Abstract: An emergency collective actuator includes an actuator motor to produce an actuation force and an actuator linkage that directly engages a friction control lever that is pivotally supported on the collective stick of a helicopter to apply the actuation force directly to the friction control lever such that the actuation force initially disengages the friction control and then reduces the adjustable pitch toward a minimum collective pitch position. The actuator can include a clutch that slips to allow the pilot to overcome the actuation force and that slips responsive to an engagement of the friction control by the pilot, but otherwise the clutch co-rotates with the motor shaft to bias the adjustable pitch toward a minimum collective pitch position.

Abstract: Discriminating between a cable locating signal and a false cable locating signal is described. A reference signal, which contains a locating signal frequency impressed on it, is transmitted in a way which provides for detection of a phase shift between the locating signal and the false locating signal. Based on the phase shift, a receiver is used to distinguish the locating signal from the false locating signal.

Abstract: A boring tool that is moved by a drill string to form an underground bore. A transmitter transmits a time varying dipole field as a homing field from the boring tool. A pitch sensor detects a pitch orientation of the boring tool. A homing receiver is positionable at a target location for detecting the homing field to produce a set of flux measurements. A processing arrangement uses the pitch orientation and flux measurements with a determined length of the drill string to determine a vertical homing command for use in controlling depth in directing the boring tool to the target location such that the vertical homing command is generated with a particular accuracy at a given range between the transmitter and the homing receiver and which would otherwise be generated with the particular accuracy for a standard range, different from the particular range. An associated system and method are described.

Abstract: A helicopter includes a rotor system having a rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and which helicopter generates a Low RPM signal that is indicative of a threshold low rotational speed of the rotor. An actuator arrangement can move the collective control by exerting a force on the collective control such that the pilot is able to overcome the actuator force but which otherwise can move the collective control from a current operational position toward a minimum pitch position. A clutch can co-rotate with a motor to serve in transferring the actuation force to reduce the adjustable pitch and can slip relative to the actuator shaft assembly responsive to an application of a counterforce applied by the pilot to the collective control such that the counterforce overcomes the actuation force.

Abstract: A drive train is used at least including an input shaft and an output shaft. A clutch member is rotatable by a clutch shaft about an axis of rotation. The clutch shaft is supported for lateral movement along the axis of rotation to move the clutch member to cooperate with the drive train at a first lateral position to cause the output shaft to turn and to move the clutch member to a second lateral position to disengage the output shaft from rotation of the input shaft. A permanent magnet is supported by one end of the clutch shaft and arranged for receiving an external magnetic biasing force along the axis of rotation to selectively move the clutch member between the first and second lateral positions. A traveling shaft can be used to support a selected gear for movement by the permanent magnet to implement transmission and reversing configurations.

Abstract: An autopilot system includes an actuator arrangement that receives control signals to influence the flight of the helicopter in a selected one of a plurality of different flight modes. A control stick input arrangement allows flight mode selection and control with no more than a particular one of the pilot's hands in the engaged position on the stick and without moving the hand away from the engaged position. A slaved gyro output signal is based on no more than the set of sensor outputs used by the autopilot such that an autopilot display presents autopilot flight mode information while displaying a slaved gyro output. The autopilot provides for pilot selection of one of a subset of the plurality of flight modes which is customized based on a current flight status of the helicopter. An automatic autorotation mode is provided.

Abstract: A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.

Abstract: An apparatus and method are used in conjunction with a system for performing horizontal directional drilling, the system including a drill string extending from a drill rig to a boring tool such that the boring tool is steerable based on a roll orientation. The system also includes an arrangement for generating steering commands for guiding the boring tool to a target position. Responsive at least in part to the steering commands, a display is configured to selectively indicate each of a rotate command, a push command and a spin command. A steering indicator is described which indicates a current roll orientation of the boring tool. A 3-D grid can be animated and centered on either a steering or target indicator. Rounding of a steering command ratio can limit the display of target roll orientations to only those that a given boring tool transmitter is capable of sensing and indicating.

Abstract: Generally, a sonde, associated components and methods are described which can be used in conjunction with an inground tool having an inground tool housing that defines an inground tool cavity such that the inground tool cavity is exposed to an ambient pressure environment which surrounds the inground tool during an inground operation. A sonde housing assembly includes an exterior configuration that is receivable within the inground tool cavity. The sonde housing assembly at least partially defines a sonde interior and is further configured for receiving the pressure sensor body of a pressure sensor in a pressure sealed engagement. A sonde electronics package is supported within the sonde interior and is at least configured to receive the pressure signal and transfer a corresponding pressure signal from the sonde.

Abstract: Location determination is performed using a transmitter including an elongated generally planar loop antenna defining an elongation axis. The elongation axis is positioned along at least a portion of a path. A magnetic field is then generated which approximates a dipole field. Certain characteristics of the magnetic field are then determined at a receiving position radially displaced from the antenna elongation axis. Using the determined certain characteristics, at least one orientation parameter is established which characterizes a positional relationship between the receiving position and the antenna on the path. The magnetic field may be transmitted as a monotone single phase signal. The orientation parameter may be a radial offset and/or an angular orientation between the receiving position and the antenna on the path. The antenna of the transmitter may be inserted into a first borehole to transmit the magnetic field to a receiver inserted into a second borehole.

Abstract: Systems, apparatus and methods are described for purposes of initiating a response to detection of an adverse operational condition involving a system including a drill rig and an inground tool. The response can be based on an uphole sensed parameter in combination with a downhole sensed parameter. The adverse operational condition can involve cross-bore detection, frac-out detection, excessive downhole pressure, a plugged jet indication and drill string key-holing detection. A communication system includes an inground communication link that allows bidirectional communication between a walkover detector and the drill rig via the inground tool. Monitoring of inground tool depth and/or lateral movement can be performed using techniques that approach integrated values. Bit force based auto-carving is described in the context of an automated procedure.

Abstract: A boring tool moves having a pitch orientation, a yaw orientation and a roll orientation and is steerable underground using the roll orientation. A maximum drill string curvature is established for steering. The boring tool is advanced over a path segment. An averaged roll characteristic is determined for movement of the boring tool along the path segment. A path segment pitch orientation is established based on at least one measured pitch orientation along the path segment. Using the maximum drill string curvature in combination with the averaged roll characteristic and the path segment pitch orientation, the yaw orientation is determined. The averaged roll characteristic is determined based on a series of incremental roll measurements that are spaced across the path segment. A set of coupled ordinary differential equations is used to characterize movement of the boring tool.

Abstract: An inground housing supports a transmitter for receiving electrical power from a battery. The transmitter transmits at least one signal using at least two different transmit power levels for at least one of locating the transmitter and characterizing an orientation of the transmitter. Based on detecting the battery voltage, the transmitter selects one of the transmit power levels. Transmitter output power can be controlled based on one or both of signal gain and duty cycle.

Abstract: A transmitter for inground use controls a depth signal transmit power in relation to a data signal transmit power such that one reception range of the depth signal at least approximately matches another, different reception range of the data signal. A portable device can form a system with the transmitter in which the portable device scans a plurality of frequencies within at least one low frequency depth signal range to measure the electromagnetic noise at each one of the plurality of frequencies and identify at least one of the frequencies as a potential depth frequency for the transmitter. The portable device can include a dual mode filter having a rebar mode and a normal mode filter. The depth signal frequency is dynamically positionable in relation to low frequency noise.

Abstract: A portable device and associated method are described for use with a system in which a locating signal is transmitted from within the ground during an operational procedure. The locating signal includes a transmission frequency that is selectable from a group of discrete transmission frequencies in a frequency range and the region includes electromagnetic noise that can vary. The portable device includes a receiver having a bandwidth that includes the transmission frequency range and is operable for measuring the electromagnetic noise in the transmission frequency range to establish a frequency content of the electromagnetic noise for use in selecting one of the discrete transmission frequencies that is subsequently transmitted as the locating signal during the operational procedure. The locating signal can be transmitted from a boring tool, a pullback arrangement or an inground cable. A predicted maximum operational depth for a transmitter can be determined prior to the operational procedure.

Abstract: An inground isolator and associated method can provide an electrically isolated break in a drill string using electrical insulating members/isolators that are supported by a housing. During drill string operations, the isolators are subject only compressive forces responsive to both extension (pushing) and retraction (pulling) by the drill string. The isolators can be formed from an electrically insulating material such as a ceramic material. An interchangeable inground tool system is described which integrally serves to provide an electrically isolating gap in the drill string.

Abstract: A steering tool is movable by a drill string to form an underground bore along an intended path. A sensing arrangement of the steering tool detects its pitch and yaw orientations at a series of spaced apart positions along the bore, each position is characterized by a measured extension of the drill string. The steering tool further includes a receiver. At least one marker is positioned proximate to the intended path, for transmitting a rotating dipole field to expose a portion of the intended path to the field for reception by the receiver. The detected pitch orientation, the detected yaw orientation and the measured extension of the drill string are used in conjunction with magnetic information from the receiver to locate the steering tool. The steering tool may automatically use the magnetic information when it is available. A customized overall position determination accuracy can be provided along the intended path.