SONIC WAVE GENERATING APPARATUS

PURPOSE:To enhance measuring accuracy, by allowing a hammer member to collide with a wall surface by the operation of a fluid and generating a sonic wave by hammering. CONSTITUTION:This apparatus is constituted of an apparatus main body 11, a fixing member 12, a protruding contact element 13, a cylinder part 14, a hammer member 15 and an operation member 16. High pressure air is supplied to the front chamber 14b of the cylinder part 14 from a cylinder 26 through an air passage 30 by the operation of a solenoid valve 27 and the member 15 is moved to a start position colliding with a lid body 23. Next, the operation of the valve 27 is changed over and high pressure air is sent into the rear chamber 14a of the cylinder part 14 in large quantities at a high speed through an air passage 29 while the front chamber 14b is allowed to communicate with a discharge port 31. By this method, the member 15 moves from the start position toward the front end surface of the cylinder part 14 at a high speed to collide with said front end surface. The impact due to the collision of this member 15 is transmitted to the protruding contact element 13 and impact sound is transmitted to a rock bed 8 through the protruding contact element 13. By this method, a sonic wave can be transmitted to the rock bed 8 and the enhancement of measuring accuracy is attained.