Abstract: A laser transmitter is provided including a specialized compensator assembly damping mechanism. In accordance with one embodiment of the present invention, a compensator assembly position detector is arranged to detect a position X1 of the compensator assembly with respect to the X-axis, and a position Y1 of the compensator assembly with respect to the Y-axis. The compensator assembly damping mechanism includes an X-axis magnetic damping mechanism, a Y-axis magnetic damping mechanism, and a rotational damping mechanism. The active feedback circuit is arranged to (i) drive the X-axis magnetic damping mechanism so as to increase a damping force generated by the X-axis magnetic damping mechanism as a rate of change of the signal indicative of the position x1 increases, and (ii) drive the Y-axis magnetic damping mechanism so as to increase a damping force generated by the Y-axis magnetic damping mechanism as a rate of change of the signal indicative of the position y1 increases.

Abstract: An arrangement is provided for determining the relative angular orientation between an excavator bucket and the dipper stick of an excavator. The excavator bucket is mounted on a bucket linkage that is pivotally secured to the end of the dipper stick. A hydraulic actuator has a hydraulic cylinder pivotally connected to the dipper stick, and a piston rod pivotally connected to the bucket linkage. Extension or contraction of the hydraulic actuator causes the excavator bucket to be pivoted by the bucket linkage with respect to the dipper stick. A cable extension linear position transducer having a transducer casing, a sheath extending from the casing to a pulley system, and an extensible belt cable extending from the sheath through the pulley system to an end of the piston rod, provides an electrical output related to the extension of the belt cable from the sheath. A transducer mounting secures the casing of the cable extension linear position transducer in fixed relationship to the hydraulic cylinder.

Abstract: A laser receiver is provided that is capable of providing an accurate indication of laser receiver tilt and correcting a generated elevation signal based upon the indicated laser receiver tilt. In accordance with one embodiment of the present invention, a laser receiver is provided comprising a laser beam detection unit, an inclination detection unit, and suitable laser receiver control circuitry. The laser beam detection unit is arranged to enable production of an elevation signal indicative of an elevation of a laser beam relative to the laser receiver. The inclination detection unit comprises a reference light source, an optical fiber, and an optical detector. The optical fiber defines a light input end and a light output end and is coupled to the reference light source such that light from the reference light source enters at the light input end and exits from the light output end as an output beam of light. The optical detector is arranged to receive the output beam of light.

Abstract: A laser beam transmitting system is provided comprising at least one target, a laser detection module, an optical system, a rotary encoder, a dither zone memory, and a controller. The optical system is arranged to generate a reference laser beam selectively in one of a search mode and a target dither mode and to direct a laser beam reflected from the target to the laser detection module. The search mode is characterized by movement of the reference beam through a rotational arc defined about a central rotational axis and the target dither mode is characterized by movement of the reference beam through a selected discrete portion of the rotational arc. The rotary encoder is arranged to produce a rotary signal indicative of a rotary position of the reference beam relative to the rotational arc.

Abstract: A blade control system is configured to control the spatial orientation of an earthmoving blade mounted on a frame of an earthmoving machine for working a surface of earth to a desired shape. The blade slope angle required to maintain a selected cross-slope angle is calculated and the blade slope is then controlled so that the sensed blade slope angle is substantially equal to the calculated blade slope angle. The method and apparatus of the present invention is capable of maintaining the desired cross-slope even when the motorgrader is steered through a turn. The control system includes an input circuit, a sensor system and a processor. The input circuit is arranged to generate an output signal representative of the desired shape of the surface of earth to be worked. The sensor system includes a first sensor coupled to the frame of the earthmoving machine to generate a first signal indicative of a longitudinal slope angle of the frame with respect to horizontal.

Abstract: An arrangement is provided for determining the relative angular orientation between an excavator bucket and the dipper stick of an excavator. The excavator bucket is mounted on a bucket linkage that is pivotally secured to the end of the dipper stick. An hydraulic actuator has an hydraulic cylinder pivotally connected to the dipper stick, and a piston pivotally connected to the bucket linkage. Extension or contraction of the hydraulic actuator causes the excavator bucket to be pivoted by the bucket linkage with respect to the dipper stick. A cable extension linear position transducer having a transducer casing, a sheath extending from the casing, and an extensible cable extending from the sheath, provides an electrical output related to the extension of the cable from the sheath. A transducer mounting secures the casing of the cable extension linear position transducer in fixed relationship to the hydraulic cylinder. A clip secures the extensible cable to the piston.

Abstract: A laser transmitter and a method of transmitting a reference laser beam are provided comprising an auto scan dither mode. According to one aspect of the present invention, a laser transmitter is provided comprising a laser detection module, an optical system, and a controller. The laser detection module is operative to produce a reflected laser beam signal. The optical system is arranged to generate a reference laser beam selectively in one of a search mode and a target dither mode and to direct a reflected laser beam to the laser detection module. The optical system defines a rotational axis and the reference beam projects radially from the rotational axis. The search mode is characterized by movement of the reference beam through a rotational arc defined about the rotational axis and the target dither mode is characterized by movement of the reference beam through a dither zone occupying a portion of the rotational arc.

Abstract: A system and method for leveling an apparatus are provided. The position of the apparatus with respect to a pair of intersecting axes is determined by sensors positioned along each axis. The position of the apparatus is adjusted about a second set of axes by first and second leveling devices. The data from each of the sensors is transformed to new position data which corresponds to the position of the apparatus with respect to the second set of axes. The apparatus may be leveled automatically through direct control of the first and second leveling devices. The apparatus may also be leveled manually through the use of an indicator device which indicates the necessary adjustments for the first and second leveling devices.

Abstract: A laser transmitter includes an optical system arranged to generate laser beam and configured to project the laser beam radially so as to define a plane through which the laser beam is projected. A positioning device is coupled to the laser transmitter for adjusting an angular orientation of the optical system with respect to a first axis and with respect to a second axis. The angular orientation of the laser transmitter is adjusted so that the plane through which the laser beam is projected has a first slope with respect to the first axis and a second slope with respect to the second axis. A rotary encoder is arranged to determine a rotary position of the laser beam as it rotates to define the plane. A target is positioned in an alignment direction corresponding to the direction to which the laser transmitter is to be aligned. The laser transmitter may be aligned with respect to the first axis, the second axis or some other reference.

Abstract: A light detection system is provided including a switching circuit connected to an inductor shunted across a photoelectric cell and operative to switch between a light detection state and a charge storage state, wherein the light detection state causes a majority of current flowing through the inductor to bypass the charge storage circuit, and wherein the charge storage state causes a majority of current flowing through the inductor to pass through the charge storage circuit. In one embodiment of the present invention, the switching circuit is changed to the light detection state during a first period of time during which the laser beam is in the vicinity of the photoelectric cell and to the charge storage state during a second period of time during which the laser beam is remote from the photoelectric cell.

Abstract: A system and method for checking and calibrating, if necessary, the orientation of a rotating laser beam as projected by a laser transmitter is provided. The laser transmitter is initially adjusted so that the rotating laser beam defines a plane which will be substantially horizontal if the transmitter is properly calibrated. A retroreflective target is positioned a predetermined distance from the transmitter. A known point on the transmitter is aligned in the direction of the retroreflective target. The laser beam is reflected from the retroreflective target back to the laser transmitter. A photodetecting system within the laser transmitter generates a signal representative of the position of the laser beam on the target. The laser transmitter is then rotated about a reference axis until the position of the laser beam on the target is determined with respect to each of the remaining coordinate axes.

Abstract: A sensor assembly for monitoring shocks and vibrations on sensitive devices is provided. The sensor assembly comprises a detector beam supported between a pair of support members. A detector weight is secured to the detector beam between the support members. The detector beam is fracturable in response to the application of a predetermined level of force. An electrical circuit may be coupled to the detector beam for monitoring electrical continuity and structural integrity of the detector beam. The detector beam provides passive monitoring as the detector beam will fracture irrespectively of the power state of the electrical circuit. One or more detector beams may be used to monitor forces along a variety of different axes.

Abstract: A device for leveling a laser transmitter is provided. An optical position sensor is used to measure the position of a compensator assembly. The compensator assembly automatically adjusts the position of the laser beam once the compensator assembly is within a specified range of level. Once the compensator assembly is within the specified range, the compensator assembly optically adjusts the laser beam so that it is plumb. A leveling device may be used to level the laser transmitter in response to the position of the compensator assembly as measured by the position sensor.

Abstract: A laser beam transmitting system is provided comprising at least one target, a laser detection module, an optical system, a rotary encoder, a dither zone memory, and a controller. The optical system is arranged to generate a reference laser beam selectively in one of a search mode and a target dither mode and to direct a laser beam reflected from the target to the laser detection module. The search mode is characterized by movement of the reference beam through a rotational arc defined about a central rotational axis and the target dither mode is characterized by movement of the reference beam through a selected discrete portion of the rotational arc. The rotary encoder is arranged to produce a rotary signal indicative of a rotary position of the reference beam relative to the rotational arc.

Abstract: A system for distinguishing real target reflections from ghost target reflections for use in adjusting the orientation of a plane defined by a rotating laser beam from a laser transmitter is provided. One or more retroreflective targets are positioned in desired locations along a rotational arc to define the desired plane through which the laser beam is rotated. The laser beam rotates back and forth scanning for targets positioned along the rotational arc. The laser beam is reflected from the targets to the laser transmitter for processing. A plurality of detection zones are established within the rotational arc. The detection zones are associated with a direction of rotation of the laser beam so that the laser beam traverses a target prior to traversing a potential shiny surface which could cause a ghost target reflection. As the laser beam scans a target prior to a shiny surface, reflections received after a target reflection are ignored as being potentially invalid reflections.

Abstract: A laser beam receiver is provided wherein the position of a laser beam incident upon an array of a plurality of photosensitive cells is calculated by coupling the plurality of photosensitive cells to a plurality of signal amplifiers, wherein each subset of adjacent photosensitive cells is coupled to a distinct subset of amplifiers among the plurality of signal amplifiers and wherein each non-adjacent mutually-coupled cell subset is connected to a single one of the plurality of signal amplifiers; and calculating the position of the laser beam based upon amplified signals read at the plurality of signal amplifiers.

Abstract: An autofocusing system for a laser transmitter is provided. A laser beam is swept across a target having a plurality of sections. The target includes a first reflective section and a second reflective section with a non-reflective section positioned therebetween. A photodetector detects a signal representative of the laser beam reflected from the target. The laser beam is focused by adjusting the focusing lens until a ratio of the duration of the non-reflective portion of the signal to the sum of the durations of the reflective portions of the signal is maximized.

Abstract: A self-aligning laser transmitter having a dual slope grade mechanism is provided. The laser transmitter includes a light source coupled to a frame which is suspended from a gimbal mechanism. The gimbal mechanism and the frame are coupled to a rotatable base. X and Y axes leveling devices are coupled to the gimbal mechanism and the frame to level the light source. A grade arm having two level sensors mounted at ninety degrees to one another is coupled to the frame. The grade arm is pivoted along the X or Y axes by a grade arm pivoting device. The X and Y axes leveling devices reposition the light source so that the level sensors are level thereby introducing a slope to the light source corresponding to the amount of pivot of the grade arm. The base may be rotated for a dual slope capability. The laser transmitter may be self-aligned automatically by aligning the laser transmitter with a target positioned at a reference location.

Abstract: The present invention is an apparatus and method for accurately determining the position of a tool, for example an earthmoving bucket, mounted at the end of an arm which has a plurality of pivot points and is pivotally attached to the base of a machine, for example a piece of construction equipment like the platform of an excavator or other earthmoving machine. The present apparatus includes a plurality of reflectors mounted on the machine for indicating movement of the arm and the tool. Each reflector is operatively adapted for reflecting light back toward a light source. A light transceiver is mounted on the machine in a known relationship to the reflectors. The light transceiver is operatively adapted for transmitting a beam of light to illuminate each of the reflectors, thereby generating reflective light. The light transceiver detects the reflective light and the angular orientation of the reflective light it detects.

Abstract: A system for adjusting the orientation of a plane defined by a rotating laser beam from a laser transmitter is provided. The laser beam is swept across one or more targets having a plurality of sections. The targets each include a first reflective section and a second reflective section with a non-reflective section positioned therebetween. The non-reflective section includes a portion which slopes across the reflective sections. A photodetector detects a signal representative of the laser beam reflected from each of the targets. The orientation of the laser beam is adjusted until the laser beam traverses the center of the target at which point the width of the first reflective section equals the width of the second reflective section. A processor calculates the distance or angle in which to adjust the laser transmitter so that the laser beam traverses the center of the target once the laser beam traverses the portion of the target including the sloped non-reflective section.