DOWNHOLE PNEUMATIC PERCUSSION MECHANISM Russian patent published in 1997 - IPC

FIELD: mining machinery, in particular, valveless downhole pneumatic percussion mechanism of closed type applicable in hole drilling in rocks of mean and high hardness. SUBSTANCE: use of split bushing embracing neck of hammer which are located in sleeve and installed in body in combination allows formation of circular and end chambers of working stroke providing increased working area of hammer in working stroke which is larger than the sectional area of body hollow and serves as base for provision of high energy parameters. Formed between working chambers is idle stroke chamber which is connected by means of channel with supplying channel and constantly being under pressure and capable of moving the hammer in idle stroke for considerable value providing for large working stroke to increase possibility of expansion of compressed air and to increase energy of single impact. There is no exhaust from idle stroke chamber to atmosphere to avoid unproductive consumption of compressed air occurring in emptying of parasite volumes which are always present in chambers. EFFECT: higher efficiency. 1 dwg