| 摘要 |
PROBLEM TO BE SOLVED: To provide a positioning device for underground excavating machine which is constituted to prevent of mechanical and vibrational measuring errors by eliminating the need of the operation for irradiating a position detecting element with light emitted from a diffused light source at measuring time, and to improve the reliability of measurement made by using the diffused light. SOLUTION: After a base point of measurement, one or more intermediate points of measurement, and a point to be measured are successively set, a measurement unit 400 provided with a common lens 411 which condenses diffused light rays from front and rear light sources 41 and 42, position detecting elements 412-2 and 412-1 which detect the receiving position of the condensed light rays, reflection prisms 413-1 and 413-2 which transmit the diffused light rays which are about to be made to incident to the lens 411 and introduce the light condensed through the lens 411 each position detecting elements 412-1 and 412-2, and the light sources 41 and 42 which emit the diffused light rays which are directed forward and backward by means of the prisms 413-1 and 413-2 is installed to each point of measurement. Then a position measuring instrument measures the position of the point to be measured relatively to the base point of measurement based on the detected results of the units 400 and the separately measured distances among the units 400. When each unit 400 successively detects the receiving positions of the diffused light rays from the light sources 41 and 42, the light source other than the light source which emits the light to be detected for its receiving position is turned off. |
