| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small and lightweight movable mechanism requiring no special power at low cost by oscillating the ramp of a channel and the plates in a throat, respectively, through a link mechanism and operating each link mechanism forward and reversely utilizing the displacement of a shape memory alloy due to power supply and the force of a bias spring. SOLUTION: Since a plurality of ramps 3a, 3b and a plate 3c are not oscillated before starting operation, power is not fed to the shape memory band alloy material 13 of a movable mechanism 18 and a plurality of link mechanisms 6, 6' are stopped at predetermined start positions by means of a bias spring 14. When the operation is started, a pressure sensor 17 detects a pressure at a moment of time when a vertical shock wave passes through a throat 4 and when a control circuit 15 decides that the detected value has reached a specified level, power is fed to the shape memory band alloy material 13 thus shortening the length thereof. Consequently, each link mechanism 6, 6' is turned to set each channel ramp 3, 3' and the plate 3c in the throat 4 at specified angles thus reducing the cross-sectional area of channel of the throat 4.
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