Abstract: A drilling system performs underground boring using a drill rig and a boring tool which is configured for moving through the ground under control of the drill rig to form an underground bore. A monitoring arrangement, forming part of the system, includes a detection arrangement at the drill rig for monitoring at least one operational parameter to produce a data signal relating to at least one of a utility to be installed in the underground bore, the drill rig and the boring tool. A portable device forms another part of the system for receiving the data signal relating to the operational parameter for use by the portable device. A communication arrangement, for example using telemetry, transfers the data signal from the drill rig to the portable device. The operational parameter may be monitored for the purpose of preventing equipment failure.

Abstract: A transmitter is part of a cable locating system for use in a region which contains at least first and second in-ground cables, each of which cables includes an electrically conductive component such that, when the first cable is driven at a locating signal frequency to emit a locating signal in an electromagnetic form, the locating signal is coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form. The transmitter generates the locating signal frequency for coupling onto the first cable and for transmitting a reference signal, which includes the locating signal frequency such that the reference signal includes a modulation envelope for comparison of the modulation envelope to the locating signal and to the false locating signal at a receiving location to distinguish the locating signal from the false locating signal.

Abstract: An arrangement and an associated method are described in which a boring tool is moved through the ground within a given region along a path in which region a cable is buried. The boring tool and the cable transmit a boring tool locating signal and a cable locating signal, respectively. Intensities of the boring tool locating signal and the cable locating signal are measured along with a pitch orientation of the boring tool. Using the measured intensities and established pitch orientation, a positional relationship is determined to relative scale including at least the boring tool and the cable in the region. The positional relationship is displayed to scale in one view. The positional relationship may be determined and displayed including the forward locate point in scaled relation to the boring tool and the cable. Cable depth determination techniques are described including a two-point ground depth determination method.

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 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.

Abstract: Tension monitoring is described using a sensor which may exhibit an offset for which compensation may be provided to produce a zero voltage amplified output or to increase dynamic range. An arrangement determines whether a power reset is responsive to a battery bounce such that an initially-measured system start-up parameter can be retained. The start-up parameter is automatically saved at start-up if the power reset is responsive to a start-up from a shut-down condition. The start-up parameter may be a zero tension amplified output responsive to the sensor offset at zero tension. Protection of a tension data set is provided such that no opportunity for altering the data set is presented prior to transfer of the data set. A housing configuration forms part of an electrical power circuit for providing electrical power to an electronics package from a battery.

Abstract: A portable locator and method for establishing the location of the cable line in a region which includes at least one generally straight electrically conductive cable line extending across the region from which cable line a locating signal includes a first arrangement for measuring a local flux intensity of the locating signal at a first above ground point within the region with the portable locator in a particular orientation at the first above ground point. A second arrangement uses the local flux intensity to establish a cable line angular orientation which limits the possible directions to the cable line relative to the particular orientation of the portable locator at the above ground point. A third arrangement uses the measured local flux intensity to establish an actual direction of the cable line that is selected from the possible directions based on certain characteristics of the locating 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: 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 pilot control interface and method are described for selective control of an autopilot system by a pilot of an aircraft in which the autopilot system is installed. The pilot control interface includes a passive network that is selectively switchable between a plurality of states across an output interface that is made up of no more than two conductors that are in electrical communication with the autopilot system. Modification of a current autopilot flight mode can be performed incrementally or continuously based on respective momentary and continuous pilot input actuations.

Abstract: A system includes a transmitter for use in conjunction with a horizontal directional drilling system that transmits a multi-bit symbol stream that characterizes sensor symbols for receipt by an aboveground portable device. The portable device receives the symbol stream for aboveground recovery of the sensor signals. The transmitter can precisely place the symbol frequencies at least to avoid a noise environment, as well as to avoid powerline harmonics, and can utilize wave shaping for transmitted symbols at least to provide for transmission power control, spectral content control and wideband antenna matching. The receiver can measure the noise environment to identify the symbol frequencies used by the transmitter. The noise can be scanned at an incremental resolution across a wide frequency bandwidth for display or automatic symbol frequency selection.

Abstract: A portable locator and method for establishing the location of the cable line in a region which includes at least one generally straight electrically conductive cable line extending across the region from which cable line a locating signal includes a first arrangement for measuring a local flux intensity of the locating signal at a first above ground point within the region with the portable locator in a particular orientation at the first above ground point. A second arrangement uses the local flux intensity to establish a cable line angular orientation which limits the possible directions to the cable line relative to the particular orientation of the portable locator at the above ground point. A third arrangement uses the measured local flux intensity to establish an actual direction of the cable line that is selected from the possible directions based on certain characteristics of the locating signal.

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: A pilot control interface and method are described for selective control of an autopilot system by a pilot of an aircraft in which the autopilot system is installed. The pilot control interface includes a passive network that is selectively switchable between a plurality of states across an output interface that is made up of no more than two conductors that are in electrical communication with the autopilot system. Modification of a current autopilot flight mode can be performed incrementally or continuously based on respective momentary and continuous pilot input actuations.

Abstract: An autopilot actuator includes first and second motors each including a rotatable motor output shaft such that either one or both of the motors can drive an actuator output shaft. An autopilot main unit enclosure is removably mounted to the helicopter proximate to a cyclic control and commonly houses autopilot actuators as well as main autopilot electronics. A cyclic vibration isolator is removably supported by an actuator shaft for co-rotation and coupled to the cyclic control to attenuate a cyclic vibration frequency at the actuator shaft while output rotations of the actuator shaft below a resonant frequency are coupled to the cyclic control. A force limited link includes first and second ends and a variable length between. The force limited link having a relaxed length when less than an unseating force is applied and the variable length changes when an applied force exceeds the unseating force to permit pilot override.

Abstract: An assembly for transferring information to and/or from flexible sheet media in a highly advantageous curved configuration is disclosed. The sheet material includes a length and a width defining first and second opposing surfaces. The assembly includes support means for supporting the sheet the curved configuration across its width, having the first surface inwardly oriented with respect to the curved configuration. Thereafter, moving means moves the flexible sheet material so supported in a direction along a read/write path generally parallel to the sheet material length and transverse to the direction of curvature. A read/write arrangement is provided which is configured for reading and/or writing information across the width of the first surface of the sheet as the sheet is moved along the path in the curved configuration.

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: An accelerometer arrangement and method are described for determining accelerations of an inground tool. First and second triaxial accelerometers are supported such that a normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer for determining the accelerations along the three orthogonal axes based on a combination of sensing axis outputs from one or both of the triaxial accelerometers. A weaker sensing axis of one triaxial accelerometer can be supported at least approximately normal to a weaker sensing axis of another triaxial accelerometer such that the weaker axes are not used. The triaxial accelerometers can be supported such that one axis of one accelerometer can be redundant with respect to another axis of another accelerometer. One triaxial accelerometer can be mounted on a tilted plane with respect to another triaxial accelerometer.

Abstract: Arrangements, apparatus and associated methods are described for use in a multi-frequency boring tool locating system. The boring tool includes a transmitter for transmitting a locating signal at two or more selectable frequencies. One set of above ground procedures may be applied to the transmitter in order to change the frequency of the boring tool transmitter. Another set of procedures is applicable for changing the frequency during below ground drilling operations, for example, by subjecting the boring tool to a predetermined roll orientation sequence. An enhanced portable locator operates in a manual or automatic mode to receive locating frequency information transmitted from the boring tool transmitter including frequency updates. Boring tool transmitter, as well as above ground locator shutdown/restart procedures are described relating to multi-frequency operation. A tone detector is described which implements one or more digital match filters.

Abstract: An autopilot actuator includes first and second motors each including a rotatable motor output shaft such that either one or both of the motors can drive an actuator output shaft. An autopilot main unit enclosure is removably mounted to the helicopter proximate to a cyclic control and commonly houses autopilot actuators as well as main autopilot electronics. A cyclic vibration isolator is removably supported by an actuator shaft for co-rotation and coupled to the cyclic control to attenuate a cyclic vibration frequency at the actuator shaft while output rotations of the actuator shaft below a resonant frequency are coupled to the cyclic control. A force limited link includes first and second ends and a variable length between. The force limited link having a relaxed length when less than an unseating force is applied and the variable length changes when an applied force exceeds the unseating force to permit pilot override.