| 摘要 |
A device for generating warning signals consisting of sound waves at frequencies between 14 and 26 kHz, preferably intended to be mounted on a motor vehicle so that the device will be actuated by the wind. The device operates similar to a flue pipe and generates a subatmospheric pressure behind the sharp edge of the flue pipe. The subatmospheric pressure is created by a passage continuing to a resonant chamber, open at its rear end, the passage being larger in cross-section than the resonant chamber. The passage is formed in a body which has substantially the shape of a frustum of a cone and is formed with longitudinal through slots which extend from the passage. With this design, a subatmospheric pressure is generated which excites the pipe to vibrate even in a relatively slow wind. |
