| 摘要 |
<p>The safety equipment crises a pocket sized means of summoning aid out of doors in the form of an inflatable balloon and a cylinder of lighter-than-air gas. The balloon has its neck attached to the open end of a cylindrical section containing a central bore holding a spring-loaded disc against its seating. Connected to this section by an external carrier ring and internal channel is a gas container which has an inner chamber with a spring loaded disc at the top. In use, the gas container and upper cylinder are pressed together, so that gas flows through holes in the disc through the channel into the balloon, which is held by a cord as it rises.</p> |
