| 摘要 |
The present invention comprises a casing (1), a permanent magnet (3) mounted inside it on a rotation shaft (2), a switch (4) and a limiter (5) of the oscillations of the magnet (3), mounted on the casing (1) which, in turn, is mounted inside an envelope (6). The casing (1) is suspended on a rotation shaft (8) and has its centre of gravity (10) located opposite to the rotation shaft (2) of the permanent magnet (3) below the rotation shaft (8) of the casing (1). |
