| 摘要 |
The blind (12) carrying information to be displayed is wound on upper and lower rollers (5, 9) which are driven by a motor (19) through pulleys (18, 22, 23) connected by an endless belt (21). The pulley (23) driving the lower roller (9) is linked to it by an internal helical spring to allow relative movement and so compensate for diametric changes as the blind winds from one roller to the other. The blind is illuminated from behind and is held close to the front window of the unit by jockey rollers (13). Each of its sections has a positioning marker (15) and a display code (17) at the top edge which are sensed by a series of photo-electric detectors (16) mounted at the upper end of the display frame (1). A remote control box operated by the petrol station attendant energises the motor (19) until the code of the desired display appears opposite the detectors.
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