| 摘要 |
Apparatus for monitoring the percent of grade and controlling machinery in response thereto is disclosed. A novel grade sensor A includes a reservoir 14 filled with a translucent fluid medium 30 to a predetermined level L. Grade sensor A is adapted for attachment to associated machinery such as casing head 50 of casing pipe 40 being simultaneously bored and pushed underground. A light emitting diode 18 transmits light through the fluid containing reservoir. Light detector 16 is located opposite the diode for detecting light intensity and has an output representing the intensity. Light intensity changes due to changes in the orientation of the sensor and inclination of the surface level of the fluid medium is used to indicate changes in percent of grade. Electrical means F converts output of detector 16 into a visual display of percent of grade change. Steering apparatus is provided in the form of elongated steering skis B carried exteriously of casing head 50 having a free end 54 for providing reactionary steering force. Inflatable air bag 56 is in operational engagement with free end 54. Supply means D selectively inflate the air bags in response to visual display 84.
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