FIXED QUANTITY SCRAPING CONTROL METHOD OF UNLOADER

PURPOSE:To realize fixed quantity scraping by successively determining a management region in scraping work to find an area within the management region, and finding a scraping speed based on a scraping height, a moving distance of a scraping part and specific gravity of a cargo to be transferred so as to move the scraping part in accordance with this scraping speed. CONSTITUTION:In an unloader utilizing a bucket elevator 3, for unloading a cargo W to be transferred such as ore and grain from a cargo hold of a ship to land, in the case where fixed quantity scraping is applied to a part of a scraping area S while a scraping part 1 with a scraping width L is moved from positions (a), (b) to positions (c), (d), the scraping area S is in advance calculated based on the positions (a), (b) and positions (c), (d). Scraping weight is calculated based on the scraping area S, a scraping height and specific gravity, and this value is divided by a scraping time to obtain a fixed scraping quantity. After a scraping speed V is calculated based on the fixed scraping quantity and a scraping distance, an arbitrary part of the scraping part 1 is specified and moved by the scraping distance at the scraping speed V so as to realize fixed quantity scraping.