| 摘要 |
<p>An alarm comprising a hollow housing 11 which is adapted to be positioned on chair leg 1 by any suitable means such as a strap or clip. The ground engaging shaft 15 is connected to a spring biased electrically conductive piston 16 whilst the other end of the shaft extends through the housing such that it can reciprocate in and out of the housing. Whilst end 15A of shaft 15 remains on the ground with shaft 15 in the first position, no alarm sound is generated. If the chair is tilted such that chair leg 1 leaves the ground 2, the spring 19 biases the shaft 15 via piston 16 out of the housing to a second position whereby the electrically conductive piston 16 touches contact 22 thus causing the sound transducer to be activated.</p> |
