| 摘要 |
A novel automatic traffic responsive control is provided for controlling the energization of the reversible drive of a powered door. The traffic control includes a traffic detector which is unobtrusive or invisible, does not require any special floor preparation of fixtures, or posts or guard rails at the entrance or the exit of the doorway, and is insensitive to the presence of the swinging door in one of the zones adjacent the door which must be monitored for safety and control reasons. The traffic control involves an emitter and a detector of radiant energy, e.g., infra red, with the emitter mounted by the header substantially on the hinge line and emitting a downwardly directed energy beam of a preselected divergence which spans the path of travel of traffic approaching the doorway. The sensor is mounted adjacent the opposite jamb and has its axis of sensitivity pointed transversely of the beam of energy to define in the intersecton therewith, a three-dimensional control zone in which the presence of traffic is detected by reflected radiant energy. In the preferred embodiment, the bottom plane of the control zone is substantially parallel to the floor and the radiant energy is coded to render the control insensitive to ambient radiations.
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