| 摘要 |
The closed casing (4, 5) encloses an electrical motor (3) on the rotatable shaft of which a hammer rotates. The hammer with repeated strokes strikes against a striking surface on a wall in the casing. The wall through the hammer blows forms a vibrating membrane. The electrical motor, by means of a manoeuvring unit on the outside of the casing, can be adjusted between a rest position in which the hammer is inactive and an activated position in which the hammer rotates. The manoeuvring unit is coupled via a shaft (11) watertightly sealed against the casing to a current switch (10) enclosed in the casing for closing and breaking the current circuit in which the electrical motor and a battery unit are connected. The shaft is rotatable and capable of spring back. |
