| 摘要 |
An alarm device for detecting movement of parked automobiles provides a support for mounting on an automobile. An outer member defines a ring having an inner surface of conducting material. A helical spring is attached to the support to suspend the ring in an attitude where the ring defines an aperture in cross-section. An inner member having an outer surface of conducting material is connected by a flexible connection to the support to be suspended in said outer member and spaced from the inner surface thereof. |
