PNEUMATIC TYPE AUTOMATIC SAND AND SOIL REMOVING HAMMER

摘要

1530865 Boring earth &c P SCHMIDT 11 March 1977 [19 March 1976] 10440/77 Heading E1F A damping device 1 which is mounted between a pneumatic self-propelled displacement hammer 13 for boring holes in the ground and a casing string 15 to clamp the transmission of shock waves to the casing string 15 includes a first mandrel 3 connected to the rear end of the hammer, a sleeve 5 fixed to the mandrel 3, a second mandrel 2 connected to the casing string 15 via connector 16 and elastic elements 7 e.g. rubber rings disposed between the mandrel 2 and sleeve 5. The rubber rings 7 act between a flange 8 on the mandrel 2, the end of the mandrel 3 and an inturned flange 11 on the sleeve 5.