LOADING MACHINE SCRAPER CONVEYOR TENSIONING DEVICE Russian patent published in 1996 - IPC

FIELD: materials handling; conveyors. SUBSTANCE: tensioning device of loading machine scraper conveyor has scraper chain tensioning hydraulic cylinder, four-line three-position control valve unit one input of which is hydraulically coupled with pressure main line, pilot controlled check valve whose input and control space are hydraulically coupled with corresponding output of four-line three-position control valve unit, safety valve whose input is hydraulically coupled with piston space of scraper chain tensioning hydraulic cylinder, control hydraulic cylinder, one working space of which is connected by hydraulic line with output of safety valve, it has also restrictor and return main line. Device has three-line two-position control valve unit with spool pusher and with spring return arrangement whose input is hydraulically connected with second input of four-line three-position control valve unit, and outputs are hydraulically connected with return hydraulic main line and with input of pilot controlled check valve. Output of pilot controlled check valve is hydraulically coupled with piston space of scraper chain tensioning hydraulic cylinder, and rod space of scraper chain tensioning hydraulic cylinder is hydraulically coupled with second working space of control hydraulic cylinder and with control space of pilot controlled check valve. Hydraulic line connecting one of working spaces of control hydraulic cylinder with output of safety valve is hydraulically connected through restrictor with return main line, and rod of control hydraulic cylinder is installed for engagement with pusher of three-line two-position control valve unit. EFFECT: enlarged operating capabilities. 1 dwg