| 摘要 |
A portable security device adapted to be removably mounted on the top edge of an inwardly swinging door whereby opening of the door will automatically actuate a battery-operated alarm. The alarm includes an audible buzzer, the battery, a manual set switch, an actuation lever and associated wiring electrically connecting said components. The actuation lever is formed of spring steel and projects outwardly from a housing containing the alarm components and is biased to the alarm ON position. The lever is moved to the alarm OFF position by contact with the door frame when the door is in the closed position. Upon inward movement of the door by an intruder the lever is urged by its bias to the alarm ON position thereby actuating the alarm. A lock-in circuit may be incorporated into the main electrical circuitry of the alarm to prevent deactivation of the alarm even if the actuation lever or the set switch is moved to the alarm OFF position.
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