| 摘要 |
The invention relates to a probe assembly (1) adapted to penetrate and travel in a mass of material, comprising: a hull, a front striking zone (3) and/or a rear striking zone (4) axially opposite, for transmitting pulses to the hull, a striking piston (2) and a pneumatic motor for setting in motion the striking piston (2) so as to project it against a striking zone (3, 4) integral with the hull, a compressed-air supply for the motor, characterized by the fact that the friction of the hull and any guiding elements rigidly connected to the hull in a pulverulent mass is between a lower value f insufficient to assure the holding of the probe upon the recoil of the striking piston (2) and a higher value F preventing the probe from advancing upon the impact of the striking piston (2) on the striking zone (3, 4) so as to permit the advancement of the probe in the pulverulent material.
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