METHOD AND DEVICE FOR DIGGING EARTH BY SCRAPERS Russian patent published in 1998 - IPC

FIELD: earth moving machinery and equipment. SUBSTANCE: this relates to scraper with active front apron. According to method, digging is performed by bowl, and additional traction force for rendering help to base vehicle is created by means of apron by digging it into ground mass. Loading of scraper bowl with ground is effected at bowl digging speed which is by 5-7 km/h higher than apron digging speed which is of constant value. At reduction of bowl digging speed down to apron speed or below it, apron is automatically shifted to digging into ground mass with creation of additional traction force. Scraper for realization of aforesaid digging method has bowl of reduced cutting width and increased length of bottom which is equal to height of apron being in position before joining of blade plate with bottom and at determined angle of its incline to horizon multiplied by cotangent of incline angle of main sliding plane of protrusion prism with its incline angle to horizon which depends on angle of internal friction of loosened ground in bowl. Length of bowl bottom is 1.4-1.7 times larger than length of bottom in conventional scraper or scraper-elevator. EFFECT: higher efficiency. 4 cl