PERCUSSIVE PNEUMATIC UNIT Russian patent published in 2001 - IPC

FIELD: structural engineering; hole forming in ground for pipe driving and replacing. SUBSTANCE: unit has body and percussion tool provided with through axial holes, front and rear work areas; air distributor whose larger step is located in blowing form and smaller one is fastened in tail end of body; air duct made for joining to tail and front ends of body; plug used for joining to mentioned ends of body. Additional collapsible plug is installed in through axial hole of percussion tool. Length of additional collapsible plug is equal to or greater than percussion toll hole. EFFECT: enhanced power; enlarged service life. 2 cl, 5 dwg