IMPACT ACTION DEVICE Russian patent published in 2008 - IPC E02D7/10 E21B1/00 

FIELD: subclass of apparatus for drilling and building.

SUBSTANCE: impact action device meant for penetration into soil of metal structures, mainly long length pipes, includes a coaxial housing provided with guides receiving therein a hollow impact piston and allowing its axial displacement and a catch mounted in the bottom part of said housing. The housing has a cavity that is arranged over its working stroke chamber and filled with working fluid and receives the impact piston. A transversal divider separates said cavity into two chambers. The upper chamber continuously communicates with a drain line, and the lower one - with the upper chamber via a coaxial hole that is arranged in the transversal divider and receives the impact piston. At the end of the working stroke an annular boss of the impact piston enters the lower chamber via said hole. The diameter of said annular boss is as large as one of said hole.

EFFECT: enhanced reliability and increased service life of the device.

2 cl, 1 dwg