PURPOSE: To achieve a higher accuracy by varying a force of pressing the tip of a rod for probing to earth by several stages to determine a particle size of earth according to a relationship between vibration information data and a rotational torque at various stages.
CONSTITUTION: A rod 1 for prospecting is penetrated with a penetrator 8. The tip part of the rod 1 is rotated with a motor 3. Vibrations varying with a particle size of earth as caused by a friction between the tip part of the rod 1 or between earths, crushing of earth particles or the like with the rotation thereof is detected with an acceleration sensor 2 to be sent out to an arithmetic processing means 13. A rotational torque during the rotation of the rod 1 is also detected with a torque sensor 4 to be sent out to the means 13. Here, the larger the particle size, the larger the output of the sensor 2 during the rotation of the rod and the output of the sensor 2 and the rotational torque become larger with a larger contact pressure between the rod 1 and earth. Thus, the particle size of earth can be discriminated based on a relationship between an output signal of the sensor 2 and the rotational torque.
OGATA KOJIRO
MITSUYANAGI NAOKI
Next Patent: SOIL QUALITY DISCRIMINATOR