| 摘要 |
The arrangement includes a barrier (1) moving between two pillars( 2,3) and driven by an electric motor (4). The barrier stops the drive motor if an obstacle is detected in the path of the door. The detectors used are an array of light beams and a pneumatic detector. The light beams have a light source (5) and a corresponding light detector (6) mounted on the door pillars (2,3). An opto-electronic block (14) is fitted to the door, and is powered by a battery mounted on the door so that can be polarised to permit or block the passage of light. This method gives improved discrimination against ambient light. The pneumatic contact is formed as a rubber edge to the door. Both detectors switch off the drive motor if an obstacle is detected. |
