PILE-DRIVING HAMMER Russian patent published in 1995 - IPC

FIELD: civil engineering equipment to immerse into soil reinforced concrete piles. SUBSTANCE: pile-driving hammer includes slideway 1, hammer 2, power cylinder 4 with stepwise piston 5. Resetting cavity 11 and low pressure cavity 12 communicated between one another through overflow valves 17 are formed in power cylinder 4. Resetting cavity 11 of power cylinder 4 are directly connected to pump 15. Additional hydraulic accumulator 36 connected to control cavities 31 of overflow valves 17 and through return valve 37 with pump 15 is installed between slide valve distributor 22 and pump 15. Control cavities 31 of overflow valves 17 are isolated from resetting cavity 11 and through slide valve distributor 22 are connected periodically to pump 15 or low pressure cavity 12 of power cylinder 4. Liquid from pump 15 is fed to resetting cavity 11 and concurrently through distributor 22 into control cavities 31 of overflow valves 17 to keep up the latter in closed position. Piston 5 is reset and charging hydraulic accumulator 36 is occurred concurrently. Once pressure pulse has entered control cavity 24, slide valve 23 is switched over to shut off control cavities 31 of overflow valves 17 from pump 15, and to connect them with drainage. Overflow valves 17 are open under effect of liquid pressure in resetting cavity 11 that comes from pump 15. In so doing cavity 11 of the hammer is communicated with cavity 12. Piston 15 is accelerated. The piston stops the slide valve is switched over again to communicate control cavities 31 of valves 17 with the pump to shut off them from the drainage. Reliability of opening and keeping up valves 17 in open position at small cross sections of the hydraulic line is provided with the fact, that small volume of the liquid from control cavities 31 enters the drainage through distributor 22 in the process of opening valves 17. Hydraulic accumulator 36 promotes fast shutting valves 17 after piston acceleration. EFFECT: high efficiency of the hammer. 1 dwg