| 摘要 |
<p>There is disclosed an improved door position monitoring unit for use in a security door installation. The unit includes track means for mounting with respect to a horizontal edge of a door and movable therewith, a circuit component such as a switch mounted with respect to a stationary surface of the door installation, such as the door frame or the threshold. The circuit component is capable of being operated to attain a first condition, and a second condition which conditions can be detected by suitable circuit means. A control arm is provided to mechanically link the door to the switches, said control arm having one end thereof slidably connected to said track means, and being pivotally mounted proximate the other end thereof to the door frame, such that movement of said door will produce pivotal movement of said control arm. Actuator means are provided interconnecting the pivotally mounted end of the control arm and the circuit component such that when the door is open said circuit component will be in a first condition, with rotation of said control arm upon movement of the door to the substantially closed position, producing a second condition for said circuit component, with initial movement of the door away from the fully closed position producing pivotal movement of the control arm in an opposite direction permitting said circuit component to return to said first condition.</p> |
