| 摘要 |
PROBLEM TO BE SOLVED: To avoid excessive crushing of a soft tube regardless of the material quality or diameter of the soft tube. SOLUTION: An outer cylindrical body 10 and the inner cylindrical body 20 movable axially with respect to the outer cylindrical body 10 are provided, either one of an oscillation acoustic lens 15 and a receiving acoustic lens 23 is fixed to the outer cylindrical body 10, and the other one of them is fixed to the inner cylindrical body 20. A compression coil spring 25 energizing the inner cylindrical body 20 to the outer cylindrical body 10 in the direction allowing the oscillation acoustic lens 15 and the receiving acoustic lens 23 to approach each other is provided between the outer and inner cylindrical bodies 10, 20, and the stoppers 17, 26 prescribing the closest approach position of the oscillation acoustic lens 15 and the receiving acoustic lens 23 by mutual contact are provided to the outer and inner cylindrical bodies 10, 20. |
