| 摘要 |
<p>A scraper (16) applies a blade of polyurethane (18) in scraping contact with an ore conveyor-belt (10) in a mine. A detector (29, 34) senses when the staples at a joint (23) in the belt (10) are approaching the blade (18), and signals the air actuation system (20) of the scraper to automatically cause the blade (18) to jump back momentarily. The scraper blade (18) is automatically eased back onto the belt (10) after the joint (23) has passed. The system is used when the blade (18) and associated components have enough inertia that the jerk from the passing joint (23) could cause damage. The system is used also in conjunction with sensors which detect an absence of ore on the belt, and/or when the belt (10) has stopped moving, and which signal a requirement to retract the blade from the belt (10).</p> |
