text: The present invention relates to a door position monitoring mechanism, such as the type employed in university buildings and large office buildings or the like and more specifically to an improved wireless door position monitoring mechanism.
  Universities and large office complexes or the like often employ monitoring apparatus on doors to monitor access into the buildings and the rooms therein. Accordingly, when it is desired to monitor a number of doors at any one time, it is desirable that a mechanism be attached to a door to detect whether the door is open or closed, and that this mechanism be capable of transmitting a signal indicating door position status to a display panel or the like to provide a correct indication as to the open or closed condition of each of the doors to be monitored. To attain the desired monitoring of the status of each door, various types of apparatus are used, which are responsive to door position and capable of providing a control signal in relation thereto.
  In this regard, the prior art has several disadvantages and limitations. In general, the prior art has provided a monitoring mechanism which generally includes a monitoring system that is hard wired back to a host computer and is capable of controlling a limited number of doors generally ranging from 2, 4, 8, or 16 doors. If the end user wants to add a more doors than the monitor can handle (such as the 9th door for an 8-door controller), the end user must either physically remove and upgrade or replace the system as the system expands beyond the monitoring mechanism's designed capacity by buying an additional monitor and have it hard-wired back to the host computer. The present invention, in combination with a battery operated reading unit attached to the same door, eliminates the need of hard-wiring the door and hard-wiring back to the host computer.
  Additionally, in prior art, the intelligence of the system generally rests in a controller and not at the door. Accordingly, if power is lost, the system falls back to fail-safe or fail-secure mode and data stored in the reader will be lost. The present invention when connected to a battery operated reading unit attached to the same door, reads and stores all system data at the reader unit attached to the door, and all data is stored at the door until power is restored to the system, at which time all information passes back through the network to the host computer.
  Another disadvantage of the hard-wired systems typically found in the prior art is that these systems generally require an installer to drill holes to run wired cables to a card reader, run power back to a lock or strike, and wire door position contacts to install the door position switch. The present invention, on the other hand, may be installed at the screw hole location of a standard door latch and easily connected to battery operated reading unit and requires no drilling. Accordingly, the present invention advantageously greatly simplifies the installation procedure in this regard. That is, the present invention presents a mechanism in which the magnetic switch is built into a non-magnetic housing that attaches to the door and accepts a metal screw to secure the standard door latch to the door.
  Accordingly, it is a general object of the invention to provide a novel and improved door position monitoring assembly. A more specific object is to provide a monitoring assembly in accordance with the foregoing object which is relatively simple in its installation, and highly reliable in its operation.