Optics: measuring and testing – Position or displacement
Reexamination Certificate
1999-10-13
2002-11-12
Font, Frank G. (Department: 2877)
Optics: measuring and testing
Position or displacement
Reexamination Certificate
active
06480289
ABSTRACT:
TECHNICAL FIELD
This invention relates to a position measuring apparatus for an underground excavator, which is useful in measuring a position of excavation by the underground excavator, such as a pipe-jacking machine or a shield machine, which is advancing in the ground while excavating a tunnel, to an optical deflection angle measuring apparatus for measuring with lights a deflection angle between two line segments connecting a cardinal point to respective points set on opposite sides of the cardinal point with distances left from the cardinal point, and also to a position measuring apparatus for an underground excavator, which by using this optical deflection angle measuring apparatus, measures a position of excavation by the underground excavator advancing along a curved path.
BACKGROUND ART
For an underground excavator such as a pipe-jacking machine or a shield machine which advances in the ground while excavating a tunnel, it is necessary to enable the excavator to accurately advance along a planned line which is a preset advancing route. For this purpose, it is desired to make it possible to measure the current position of the advancing underground excavator in real time and accurately. Namely, if the underground excavator begins to advance off the planned line, an operator can quickly find out this problem and can take a countermeasure at an early stage if the operator is provided in real time with highly-reliable information on the current position of the underground excavator. Control can therefore be performed with ease to make the underground excavator advance along the planned line, and improvements in the accuracy of the work can also be expected. As techniques for measuring a position of excavation by an underground excavator, a variety of methods have been used to date including a method in which “a measurement is performed manually by using a transit”, a method in which “a position of excavation by an underground excavator is measured by arranging an oscillating coil, which generates an induction field, on the underground excavator and measuring the intensity of the induction field with a receiving coil arranged on the ground”, and a method in which “a position of excavation by an underground excavator is measured by laying a cable way conversely on the ground, causing a current to flow through the cable way to generate an induction field, and detecting the intensity of the induction field with a receiving coil arranged on the underground excavator”. However, these conventional techniques for the measurement of positions of underground excavators are inherently incapable of performing real-time measurements of positions of excavation or, even if such real-time measurements are feasible theoretically, can hardly be put into practical use.
As a position measuring technique for an underground excavator, which can reduce these problems, a direction detecting apparatus for a shield machine has been proposed as disclosed in JP 61-45092 A. This direction detecting apparatus for the shield machine, which has been proposed previously, is an apparatus in which “a first laser beam oscillator for performing radiation into a forward tunnel and a first laser beam receiver capable of receiving a laser beam from a front are mounted on a base such that they can be turned in an X direction (yawing direction) and an Y direction (pitching direction) by servomotors, a measuring instrument capable of detecting their turned angles by sensors is arranged in an entrance section to the tunnel, a second laser beam oscillator for performing radiation toward a first laser beam receiver at a rear, a second laser beam receiver capable of receiving a laser beam from the first laser beam at the rear and a third laser beam oscillator for performing radiation toward the shield machine at a front are arranged on a base such that they can be turned in the X direction and the Y direction by servomotors, a measuring relay designed to detect their turned angles is arranged in an intermediate section of the tunnel, and a third laser beam receiver and a pitching-rolling meter, which can receive a laser beam from the second laser beam oscillator at the rear and can detect the X and Y directions and a rolling angle, respectively, are arranged on the shield machine”.
Upon performing construction work on the ground or under the ground, it is necessary to determine an angle relationship between two line segments which connect a point, which serves as a cardinal point, to points set on opposite sides of the cardinal point with distances left from the cardinal point. Upon constructing a curved or bent road, it is necessary to determine the angle of the curved or bent part of the road surface under construction. In this case, a measurement point which serves as a cardinal point is set at a suitable place in the curved or bent part, measurement points are also set in road-surface working zones on the opposite sides of the cardinal point with distances left from the cardinal point, and an angle between line segments connecting the measurement point as the cardinal point to the respective measurement points on the opposite sides of the cardinal point is measured. To excavate a curved tunnel by an underground excavator, the position of excavation must be ascertained to determine whether or not the underground excavator is accurately advancing along a planned route (preset advancing route). In this case, it is also necessary to determine an angle relationship between line segments connecting a measurement point, which serves as a cardinal point, to respective measurement points on opposite sides of the cardinal point, as will be described in detail subsequently herein. To determine an angle relationship between line segments on opposite sides of such a cardinal point as an apex, either an interior angle or an exterior angle of both the line segments can be measured, and this object can be achieved if a value concerning such an angle as enabling to automatically specify the angle relationship can be measured. In this specification, a value concerning such an angle as enabling to specify the angle relationship between such two line segments is called a “deflection angle”.
In construction work, a measuring method making use of a transit has been adopted to date in general to measure such deflection angles. As this measuring method of a deflection angle by a transit is a method which relies upon human ability, it requires labor such as a skilled worker and moreover, takes a long time for each measurement. In addition, a turning mechanism is required to turn a telescope in a yawing direction (horizontal direction) and a pitching direction (vertical direction), so that mechanical measurement errors tend to occur due to this turning mechanism, thereby making it difficult to assure high measuring accuracy. Furthermore, if external force such as that causing tilting in the yawing direction and/or pitching direction, such as vibrations, is applied, a measurement error takes place by such external force, thereby affecting the results of the measurement.
Incidentally, upon excavating a curved tunnel by an underground excavator which advances in the ground while excavating a tunnel, the position of excavation by the underground excavator is measured so that the underground excavator can accurately advance along a planned route. Examples of underground excavators of this type can include small-diameter pipe-jacking machine for burying in the ground small-diameter pipes which men cannot enter and semi-shield and shield machines for burying in the ground large-diameter pipes which men can enter. To measure the position of excavation by such an underground excavator, it is the general practice to set a measuring start point and a measuring end point at a position—which serves as a start pint for excavation by the underground excavator, such as a starting shaft—and within the underground excavator, respectively, and also to set a suitable number of intermediate measuring points between the measuring start point and the measuring e
Miyanagi Naoki
Moro Takashi
Shimomura Yoshiaki
Crowell & Moring LLP
Hitachi Construction Machinery Co. Ltd.
Merlino Amanda
LandOfFree
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