Self Computing Type Rod Patents (Class 33/294)
  • Patent number: 10634795
    Abstract: The invention provides a rover, which comprises a pole of which lower end indicates a point to be measured, a measurement auxiliary apparatus provided at a predetermined position of the pole, a direction detecting device integrally provided with the measurement auxiliary apparatus and for detecting a direction of the measurement auxiliary apparatus, and an object to be measured provided at a known distance from the lower end of the pole, wherein the measurement auxiliary apparatus comprises a horizontal detecting unit which is supported so as to be rotatable around two shafts orthogonal to each other and detects the tilts in two axial directions, motors provided so as to rotate the shafts, encoders provided respectively on the shafts, and an arithmetic processing component for controlling the motors in such a manner that the horizontal detecting unit becomes horizontal based on a detection result from the horizontal detecting unit, wherein the encoders are configured to detect a rotation amount of each shaft
    Type: Grant
    Filed: January 11, 2018
    Date of Patent: April 28, 2020
    Assignee: TOPCON Corporation
    Inventors: Fumio Ohtomo, Kaoru Kumagai
  • Patent number: 10119818
    Abstract: Some embodiments of the invention relate to a surveying pole comprising at least two pole sections being telescopically insertable into each other so that a height adjustment of the pole is provided, a pointing tip at the lower end of the pole for setting the pole on a terrain point, a receptacle at an upper end of the pole for mounting a position giving means, a height measuring system for indicating the distance of the position giving means relative to the terrain point.
    Type: Grant
    Filed: December 17, 2016
    Date of Patent: November 6, 2018
    Assignee: LEICA GEOSYSTEMS AG
    Inventors: Hannes Maar, Heinz Bernhard, Josef Lais, Paul Benz
  • Patent number: 9255798
    Abstract: A survey device may include a shaft portion having a longitudinal axis, a prism having a center point and being arranged near the top of the shaft portion and offset laterally relative to the longitudinal axis of the shaft portion, and a laser having a laser emission point in general alignment along the shaft portion with the center point of the prism.
    Type: Grant
    Filed: June 10, 2014
    Date of Patent: February 9, 2016
    Inventor: Keith Kahlow
  • Patent number: 8720074
    Abstract: A method of determining an elevation of a point relative to a leveling instrument includes sending a first signal from a controller to the leveling instrument using a wireless link. The first signal indicates to the leveling instrument to automatically align an alignment unit of the leveling instrument with a reference target of a leveling staff. The method also includes receiving a second signal at the controller using the wireless link. The second signal is sent from the leveling instrument and indicates that the alignment unit is aligned with the reference target. The method also includes sending a third signal from the controller to the leveling instrument using the wireless link. The third signal indicates to the leveling instrument to automatically determine the elevation of the point relative to the leveling instrument.
    Type: Grant
    Filed: December 6, 2011
    Date of Patent: May 13, 2014
    Assignee: Trimble Navigation Limited
    Inventor: Miguel Amor
  • Patent number: 7788815
    Abstract: A prism pole has a tubular housing having an open top, a flange at the open top, a bottom portion for contacting ground soil, a height-adjustable rod insertable into the tubular housing with an outer diameter less than inner diameter of the tubular housing to provide a slidable friction fit therebetween for positioning the height-adjustable rod with respect to the tubular housing, a lip at the top of the rod, a laser sensor mounted on the tubular housing for emitting a laser toward the lip to measure distance between the laser sensor and the lip, an electronic control unit in electrical communication with the laser sensor for receiving height measurements and providing height reference data corresponding to the height measurements, an electronic display in electrical communication with the electronic control unit for receiving the height reference data and displaying the height reference data, an audio device in electrical communication with the electronic control unit for emitting an alarm in response to rec
    Type: Grant
    Filed: August 6, 2007
    Date of Patent: September 7, 2010
    Assignee: Wilkinson & Associates
    Inventors: Richard Yandrick, Edward Wilkinson, John Wilkinson
  • Patent number: 7739803
    Abstract: The present invention provides a surveying system, which comprises a surveying device 1 provided with a function for tracking a target 13, and a remote control device 16 for remotely controlling the surveying device on a target side, said surveying device comprises a measuring unit 21, an image pickup unit 23, a first radio unit 33, and a first control arithmetic unit 29, said remote control device comprises a second radio unit 37, a second control arithmetic unit 35, a second display unit 18 and a second operation input unit 20, said first control arithmetic unit transmits measurement data of the measuring unit to the remote control device via the first radio unit when a detection result is within the tracking range based on the detection result of a reflection light from the target, and transmits an image data taken by the image pickup unit via the first radio unit when the detection result is out of the tracking range, said second control arithmetic unit receives the measurement data and the image data via
    Type: Grant
    Filed: November 21, 2008
    Date of Patent: June 22, 2010
    Assignee: Kabushiki Kaisha TOPCON
    Inventors: Kazuyoshi Yahagi, Masaaki Kobayashi, Terukazu Nagashima, Yoshikatsu Miyao
  • Publication number: 20080256812
    Abstract: A prism pole has a tubular housing having an open top, a flange at the open top, a bottom portion for contacting ground soil, a height-adjustable rod insertable into the tubular housing with an outer diameter less than inner diameter of the tubular housing to provide a slidable friction fit therebetween for positioning the height-adjustable rod with respect to the tubular housing, a lip at the top of the rod, a laser sensor mounted on the tubular housing for emitting a laser toward the lip to measure distance between the laser sensor and the lip, an electronic control unit in electrical communication with the laser sensor for receiving height measurements and providing height reference data corresponding to the height measurements, an electronic display in electrical communication with the electronic control unit for receiving the height reference data and displaying the height reference data, an audio device in electrical communication with the electronic control unit for emitting an alarm in response to rec
    Type: Application
    Filed: August 6, 2007
    Publication date: October 23, 2008
    Inventors: Richard Yandrick, Edward Wilkinson, John Wilkinson
  • Patent number: 7373725
    Abstract: Disclosed herein are representative embodiments of grade rods, grade-rod readers, and combinations thereof. In one exemplary embodiment, a grade rod is provided that has a reference surface extending along at least a portion of the rod. The reference surface includes two or more reference indicators spaced at substantially even intervals from one another. A reader unit is mounted to the rod (for example, slidably mounted). The reader unit includes one or more sensors positioned proximate to at least a portion of the reference surface of the rod. The sensors of this embodiment are configured to detect the motion of at least one of the two or more reference indicators relative to the sensors as the reader unit is moved along the reference surface. Other grade rod and grade-rod reader embodiments, as well as methods for using such embodiments, are also disclosed.
    Type: Grant
    Filed: October 20, 2005
    Date of Patent: May 20, 2008
    Assignee: Laserline Mfg., Inc.
    Inventors: Robert W. Vanneman, Robert J. Blick
  • Patent number: 7251899
    Abstract: A direct reading prism pole has a tubular housing having an open top, a flange at the open top, a conical bottom portion for wedging the tubular housing into ground soil, a height-adjusting rod partially inserted into the tubular housing by a friction fit, a lip positioned at the top of height-adjustable rod, a laser sensor mounted to the outer surface of the tubular housing for emitting a laser toward the lip to take height measurements of the distance between the laser sensor and the lip, an electronic control unit for receiving the height measurements and providing height reference data, an electronic display for displaying the height reference data, an audio device for emitting an alarm indicating movement of the height-adjusting rod with respect to the tubular housing, and an output device for sending the height reference data to a data collection device.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: August 7, 2007
    Assignee: Wilkinson & Associates, Inc.
    Inventors: Richard Yandrick, Edward Wilkinson, John Wilkinson
  • Patent number: 6182372
    Abstract: A distance interpolator incorporated into a total station and a method for digitally interpolating a distance measurement from the total station to a target, such that the distance interpolator measures the distance from the total station to the target using primarily digital electronics and statistical analysis. In one embodiment, the total station transmits an energy pulse from the electronic distance measuring portion of the total station, with the energy pulse directed at the target. This embodiment then receives at the electronic distance measuring portion the energy pulse reflected from the target. This embodiment also contains a reference oscillator and digital counter, which counts the number of reference oscillator clock pulses that elapse from the time the energy pulse is transmitted to the time the reflection of the energy pulse is received.
    Type: Grant
    Filed: August 25, 1998
    Date of Patent: February 6, 2001
    Assignee: Trimble Navigation Limited
    Inventor: Robert Lamm
  • Patent number: 6167629
    Abstract: A leveling rod for an electronic level has a plurality of bar-shaped marks disposed adjacent each other in a longitudinal direction along the leveling rod in parallel with each other and perpendicular to a length of the leveling rod. The marks are arranged at a constant pitch. The width dimensions of the marks in the longitudinal direction of the leveling rod are represented by a plurality of integers. A permutation of predetermined number of values chosen from a sequence of numbers made up of a sequential array of the ratios of the width dimensions is arranged to be different from a permutation chosen from any other portion of the sequence of numbers.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: January 2, 2001
    Assignee: Sokkia Co. Ltd.
    Inventor: Minoru Chiba
  • Patent number: 6161295
    Abstract: A brake mechanism for use with a computerized grade rod comprising a housing containing a tunnel adapted to receive the grade rod and having the grade rod extend therethrough. A sensing wheel is mounted on the housing and tangentially engages the outer surface of the grade rod and rotates as the housing ascends and descends the grade rod. A brake assembly is carried by the housing in a predetermined longitudinal position with respect to the grade rod. The brake assembly includes first and second spaced apart brake shoes spaced apart longitudinally of the grade rod. A mounting plate is carried by the housing. First and second arms carry respectively the first and the second brake shoes. Each of the said brake shoes has a center point. First and second spaced apart pivot pins are provided for pivotally mounting the first and second arms. The first and second pivot pins are positioned off center with respect to the center points of the first and second brake shoes.
    Type: Grant
    Filed: January 15, 1999
    Date of Patent: December 19, 2000
    Inventors: Glenn J. Mooty, Bruce J. Richardson
  • Patent number: 6131296
    Abstract: As equipment has a transducer (G) that receives signals from a number of objects with unknown positions and senses the directions from the transducer to the objects. The directions of the sight lines to the objects are sensed in at least two separate transducer locations. The transducer signals are supplied to calculator (CU) which calculates the positions of the objects.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: October 17, 2000
    Inventor: Jan G. Fager
  • Patent number: 6085452
    Abstract: A device and method for marking a location with a marker stake. An elongate wire-like rod is partially inserted in the ground at a location to be marked, and the rod is received in a pre-sized panel having a pair of flag faces and an open-ended longitudinal channel, the channel being dimensioned to receive the rod in friction fit. The flag faces are separated by a plurality of spacers in generally parallel orientation to each other, with the spacers defining the plurality of channels, and the panel has two longitudinal ends each having a sighting notch. While inserting the rod into the ground, the panel may be disposed at the ground to serve as a guide to retain the rod against deflection. Two or more panels and rods may be joined together to produce a larger marker stake, and the panels may be oriented at right angles to each other to give the marker stake a greater three-dimensional profile.
    Type: Grant
    Filed: December 11, 1996
    Date of Patent: July 11, 2000
    Inventor: R.P. Stephen Davis
  • Patent number: 6076267
    Abstract: A leveling pole which includes a scale visibly provided on a front surface of the leveling pole and at least two colored divisions formed on the front surface of the leveling pole. A border between two adjacent colored divisions of the at least two colored divisions extends in a longitudinal direction of the leveling pole. One of the two adjacent colored divisions and the other of the two adjacent colored divisions are painted a first color and a second color, respectively. A brightness of the first color is different from a brightness of the second color.
    Type: Grant
    Filed: February 20, 1997
    Date of Patent: June 20, 2000
    Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
    Inventor: Tatsuo Gotoh
  • Patent number: 5983511
    Abstract: An apparatus for displaying a direction for adjusting its height to its appropriate height includes a plurality of light sources, a light receiving portion, and a control unit. The light sources are arranged in the form of a matrix in a display portion of the apparatus and displays the direction as a moving shape by emitting light in turn. The light receiving portion receives an incident beam and outputs a signal corresponding to a height of the incident beam. The control unit controls the light emission of the light sources in accordance with the signal so as to move the shape downward or upward to indicate the appropriate height. The control unit controls the light emission of the light sources so that at least one light source of a group of the light sources is lighted after a predetermined time, shorter than a time during which a human eye can keep an afterimage, after other members of the group were lighted.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: November 16, 1999
    Assignee: Kabushiki Kaisha Topcon
    Inventors: Kazuki Osaragi, Satoshi Hirano
  • Patent number: 5894344
    Abstract: An elevation measurement instrument including a support ruler, an optical instrument and a bracket pivotally coupling the optical instrument to the support ruler. The optical instrument includes a first ocular mount having a telescope with a horizontal crosshair and a second ocular mount having a horizontal alignment level device. The bracket couples the optical instrument to the ruler along a horizontally balanced axis. The bracket includes a position indicator colinearly aligned with the horizontal crosshair.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: April 13, 1999
    Assignee: Tamez Construction
    Inventors: Daniel Tamez, Ana Tamez
  • Patent number: 5551159
    Abstract: Scalable measuring apparatus for use by an operator with a laser beam from a laser-level transmitter comprising a vertically disposed grade pole having lower and upper extremities. A laser-level receiver is provided for detecting the laser level beam. A controller is mounted on the grade pole and carryies the laser-level receiver. At least a portion of the controller is being capable of ascending and descending the grade pole. An indicator is electrically coupled to the laser-level receiver for giving a response perceptible to the operator when the laser beam is detected by the laser-level receiver. The controller has a brake for retaining the controller at a predetermined elevation with respect to said grade pole. The controller is capable of ascending and descending the grade pole which is free of markings.
    Type: Grant
    Filed: October 11, 1995
    Date of Patent: September 3, 1996
    Inventor: Glenn J. Mooty
  • Patent number: 5457890
    Abstract: Scalable measuring apparatus for use by an operator with a laser beam from a laser-level transmitter comprising a vertically disposed grade pole having lower and upper extremities. A laser-level receiver is provided for detecting the laser level beam. A controller is mounted on the grade pole and carries the laser-level receiver. At least a portion of the controller is capable of ascending and descending the grade pole. An indicator is electrically coupled to the laser-level receiver for giving a response perceptible to the operator when the laser beam is detected by the laser-level receiver. The controller has a brake for retaining the controller at a predetermined elevation with respect to the grade pole. The controller is capable of ascending and descending the grade pole which is free of markings.
    Type: Grant
    Filed: March 22, 1993
    Date of Patent: October 17, 1995
    Inventor: Glenn J. Mooty
  • Patent number: 5402223
    Abstract: An electronic survey stadia to ascertain distance and elevation data from a rotary laser beam(s) in relation to known points. To ascertain elevation data stadia is in perpendicular position in relation to rotary laser beam plane. When beam impinges upon stadia, a measurement is taken by evaluation circuit, processed by an algorithm, then stored in memory and output to display device for use. To ascertain distance measurements, stadia is placed parallel in rotary laser beam(s) plane. The stadia self calibrates by counting rotational speed of laser beam. Once RPM and direction are established, stadia then measures time of laser beam to cover a known distance within stadia. This value is then used in an algorithm to produce distance measurements, thus producing distance and elevation data to memory and display.
    Type: Grant
    Filed: September 24, 1992
    Date of Patent: March 28, 1995
    Assignee: Smart Grade Incorporated
    Inventors: Timothy A. Schlobohm, Patrick D. Maloney
  • Patent number: 5313409
    Abstract: An arrangement for one-man surveying, including a measuring station (1) and a target unit (2). A sighting-marker arrangement is provided which can be indicated by an indicator arrangement (7) on the measuring station. The measuring station (1) automatically takes a target seeking mode when the indicator arrangement (7) does not indicate the sighting-marker arrangement and a target following mode, when the indicator arrangement indicates the sighting-marker arrangement. The sighting-marker arrangement includes a combination of a first and a second sighting-marker unit. The first unit has a light source (8) on the target unit (2). The second unit has a light source (9) on the measuring station (1) and a reflector (11) on the target unit (2).
    Type: Grant
    Filed: October 4, 1991
    Date of Patent: May 17, 1994
    Assignee: Geotronics
    Inventors: Rudolf Wiklund, Mikael Herztman, Leif Andersson, Olle Engdahl, Lars Ericsson
  • Patent number: 5272814
    Abstract: A device for defining a plane to determine relative elevations comprising in combination a stationary housing (7) having an aperture (8) and locating a pair of vertical reflecting surfaces (6) at right angles to each other which may be a pair of mirrors (5) or a right angle prism (32) and a levelling rod or staff (14) adapted to be positioned at a vewing distance from the housing (7) and incorporating a light source (12) and an eyepiece (15) whereby an observer at the location of the levelling rod (14) can move the light source (12) up and down the levelling rod (14) until a reflection of the light from the light source (12) is seen in the pair of reflecting sufaces (6). A reading can then be taken on the levelling rod (14) at a point midway between the eyepiece (15) and the light source (12) which defines a horizontal line from the reflecting surfaces (6).
    Type: Grant
    Filed: October 8, 1991
    Date of Patent: December 28, 1993
    Inventor: Bruce G. Key
  • Patent number: 5189484
    Abstract: This laser beam detector system may comprise an array of photodetectors usable in conjunction with a laser employed to define an elevation or grade. The detector array is utilized on an elongate device having a plurality of faces, with a plurality of detectors disposed in a consistently spaced arrangement on each of the faces. The detectors of each face have a field of view different from the field of view of the detectors of the other faces, and each detector on each face of the array is disposed at the same height as a corresponding detector on each of the other faces. Importantly, each group of detectors at the same height are electrically interconnected into a co-functioning group. Our novel arrangement is such that a laser beam incident on any detector of a co-functioning group is detected, with the position of the detector upon which the beam impinged being identified, and a readout indicative of that detector then provided.
    Type: Grant
    Filed: August 13, 1991
    Date of Patent: February 23, 1993
    Inventors: Eric C. Koschmann, Mark E. Taylor, Carroll D. Lifer
  • Patent number: 5087125
    Abstract: An equipment for measuring difference in elevation employing a leveling pole and a level is disclosed. The leveling pole comprises divisions of coded marks each indicating height at a unit interval. The level comprises a telescope and an image sensor. The output signal of the sensor is decoded for display of digital height value. A plate glass is provided in front of an object lens for vertical compensation of an optical axis of the telescope. An inclination angle of the plate glass required for compensation is used for interpolation between two adjacent coded marks.
    Type: Grant
    Filed: September 12, 1990
    Date of Patent: February 11, 1992
    Assignee: Optec Co., Ltd.
    Inventor: Yoshinori Narutaki
  • Patent number: 4820041
    Abstract: A position sensing apparatus and method useful for surveying, marking, and grading implement sensing and control is disclosed. The position sensing apparatus includes two laser reference stations, each of which projects a laser beam that periodically sweeps in a plane across the area to be surveyed. Each time a laser beam strikes the opposite reference station, a radio timing signal is broadcast by that reference station. The position sensing apparatus also includes a portable sensing station that comprises a laser beam receiver, a radio reciever, and a programmed computer. The planar position of the portable sensing station relative to the reference stations is computed by a triangulation technique based on the relative timing of detection of the laser beams by the laser beam receiver and the reception of the radio timing signals by the radio receiver. Elevation is determined according to the height at which one of the laser beams strikes the laser beam receiver.
    Type: Grant
    Filed: November 12, 1986
    Date of Patent: April 11, 1989
    Assignee: Agtek Development Co., Inc.
    Inventors: Richard W. Davidson, John W. Fletcher
  • Patent number: 4730920
    Abstract: An optoelectronic stadia is proposed, which is intended for a levelling system with a rotary laser. The stadia has at least one vertical row of light sensitive diodes, which are electrically connected in matrix form. One diode pair in each case forms one matrix node. The column signals and line signals are decoded and evaluated in an evaluation apparatus and the measured result is supplied to a display means. The matrix arrangement of the diodes leads to a very simple construction with relatively few components.
    Type: Grant
    Filed: March 24, 1986
    Date of Patent: March 15, 1988
    Assignee: Nestle & Fischer
    Inventors: Harald Schlemmer, Rainer Stuhlmuller
  • Patent number: 4673287
    Abstract: A laser-optical surveying system comprising a leveling system which uses a surveyor's rod wherein a laser beam rotates in a horizontal plane and is adapted to strike a surveyor's rod. The surveyor's rod is equipped with a coding representing the length, that is, in the case of a leveling system, representing the altitude, which can be read with the laser light so that an optical signal representing the altitude is generated when the laser beam passes the rod. The latter is then converted to an electronic signal and serves, when electronically processed, for displaying the height of the laser beam on the surveyor's rod.
    Type: Grant
    Filed: June 6, 1984
    Date of Patent: June 16, 1987
    Assignee: Nestle & Fischer
    Inventor: Edmund Rickus
  • Patent number: 4653910
    Abstract: A laser alignment system includes a remote indicator to display the alignment data when the main receiver is out of sight. The remote indicator receives both operating power and alignment data through a connecting cable to the main receiver. A Liquid Crystal Display (LCD) is used in the remote indicator because of its inherently low power consumption. To make the LCD visible under conditions of reduced ambient lighting, a light source illuminates the LCD from behind. A lighting control circuit turns the light source on only when alignment data is present in order to limit battery drain on the main receiver.
    Type: Grant
    Filed: October 18, 1985
    Date of Patent: March 31, 1987
    Assignee: Spectra-Physics
    Inventor: Mark E. Poling
  • Patent number: 4471532
    Abstract: A direct reading grade rod as provided with a fixed scale having display windows therein and one or more sliding members slidable behind the fixed member and carrying a plurality of number sets, with different positions of the sliding member resulting in different sequences of numbers displayed in the windows.
    Type: Grant
    Filed: May 25, 1983
    Date of Patent: September 18, 1984
    Inventor: John G. R. Francis
  • Patent number: 4345382
    Abstract: Apparatus for use in setting and checking grades in construction of roads, parking lots, building, or the like comprising a level support in combination with a level rod wherein the level support has a nominal length of X plus Y, for example, the level rod includes a zero mark above which are plus (+) graduations in terms of a principal dimension and a subordinate dimension below which are minus (-) graduations in terms of the principal and subordinate dimensions down to a length of X according to the principal dimension and a leg member adustably secured to the rod, the leg member having a foot portion extending below the lower end of the rod, the leg member being adjustable so that the foot portion may be selectively set to extend below the lower end of the rod for a minimum distance of Y according to the subordinate dimension or more as desired, whereby the zero mark may be selectively set at a distance equal to the nominal length of X plus Y above the lower end of the foot portion so that in use of the ap
    Type: Grant
    Filed: February 13, 1980
    Date of Patent: August 24, 1982
    Inventor: Dwight D. Warren
  • Patent number: 4271598
    Abstract: A surveyor's levelling staff which comprises an endless graduated band or strip on a hollow elongated body with a portion of the strip to be viewed extending along a longitudinal face of the body and the remainder of the strip disposed within the body. The strip passes around a spring-loaded tensioning roller and a winding and brake roller inside the body. The tensioning roller maintains a predetermined tension on the strip and the winding and brake roller includes a winding handle to move the strip along the longitudinal face of the body and through the body, and a brake which, in the locked position prevents relative movement of the strip.
    Type: Grant
    Filed: October 24, 1979
    Date of Patent: June 9, 1981
    Assignee: Anson Engineering Pty. Ltd.
    Inventor: Donald G. Thomas
  • Patent number: 4030832
    Abstract: A grade rod and method of operation for use in a surveying system employing a laser beam which is rotated in a plane. A flexible tape formed with a graduated scale is mounted for movement in a loop within the housing. A slider on the tape carries a pair of closely spaced-apart light detectors as well as electronic circuitry which discriminates between laser beam pulses and sunlight. Output signals from the circuitry on the slider are fed into a control circuit in the housing through a flexible cable which is carried in a traveling loop. Scale indicators are mounted for movement with the slider along a fixed scale which is provided on the housing, and a manually operated cursor is mounted for movement along the housing. The control circuit includes means for driving the tape and slider in a search mode until a light pulse from the laser hits a detector, and then in a track mode for centering the detectors on the plane of the laser beam.
    Type: Grant
    Filed: February 10, 1975
    Date of Patent: June 21, 1977
    Assignee: Spectra-Physics, Inc.
    Inventors: Joseph F. Rando, Arthur Sobel, Richard W. Davidson
  • Patent number: 4029415
    Abstract: A land-surveying apparatus for use with a laser beam source to obtain grade and range distances has a grade pole with a laser beam detection unit slidably mounted thereon, electrical measuring means being connected between the grade pole and the detection unit to generate an electrical grade signal representative of the grade distance between a detector using an array of phototransistors and the base of the grade pole. A digital display unit receives the grade signal, processes it, and digitally, visibly displays the information contained in the signal. Electrical grade calculating circuitry is provided to process first and second grade signals containing the elevation of the upper and lower edges of the laser beam relative to the base of the pole and arithmetically process the signals to obtain the elevation of the laser beam center which is then displayed as the grade distance.
    Type: Grant
    Filed: February 3, 1975
    Date of Patent: June 14, 1977
    Assignee: Dakota Electron, Inc.
    Inventor: Phillip R. Johnson