| 摘要 |
Alarm apparatus suitable for attachment to a motor-cycle for producing an audible alarm when an unauthorized person tilts the cycle from the rest position in which it was left. The apparatus comprises a casing containing the alarm circuit and a self-contained power supply, the casing being mountable in a fixed angular position on the motorcycle, preferably at the rear of the cycle so that the license plate can then be mounted over the rear of the casing. The casing is held to the cycle by fastening means which are accessible only when a removable portion of the casing is removed, and the alarm circuit is responsive to the removal of the closure portion of the casing to produce an electrical alarm signal when the closure portion is removed so that one cannot remove the entire casing or open the casing to disable it without sounding the alarm. The angle of the cycle is sensed by a pair of mercury switches within the casing, one for sensing tilt in one angular direction and the other for sensing tilt in the other direction from a reference angular position normally defined by the position in which the cycle is held by its stand. The two mercury switches are preferably independently adjustable in angular position so as to accommodate any stand angle. The battery within the casing energizes an alarm circuit whenever either one of the mercury switches is closed by tilting of the cycle or when the closure for the casing is removed, provideded also that a key-operated line switch has also been closed by the operator upon leaving the cycle. The alarm circuit includes a timing circuit such that when one of the switches has been closed and is then reopened, the alarm signal will continue for a predetermined length of time and will then terminate, thereby providing an adequate alarm in case of tampering with the cycle yet preventing continued operation of the alarm which will unduly deplete the battery supply. |
