| 摘要 |
A vehicle traffic detecting device is provided with an automatic cleaning device. The detecting device has an emitter and a receiver facing each other and respectively emitting and receiving a beam of electromagnetic radiation along opposite ends of a beam path. The cleaning device has first and second cleaning units for respectively cleaning the emitter and the receiver. Each cleaning unit includes a fastener fastening the cleaning unit to a casing of the detecting device, a dispenser dispensing a transparent film, a contoured guide defining a film path along which the dispensed film resides, and an actuator for moving the dispensed film along the defined film path. A portion of the defined film path is located in front of the emitter/receiver of the detecting device and thereby positions a portion of the dispensed film in front of the emitter/receiver of the detecting device. The cleaning device also has a controller for automatically activating the actuators of the cleaning units in response to a predetermined signal from the detecting device signifying that at least one of the portions of the dispensed films currently in front of the emitter and receiver of the detecting device is fouled. The actuators when actuated move each of the dispensed films a distance along the film path such that the fouled portion(s) are moved beyond the front of the emitter/receiver and the portion of the dispensed film newly in front of the emitter/receiver is clean. |
