AIR-DRIVEN PERCUSSION MECHANISM Russian patent published in 2015 - IPC E21B1/30 E21C37/22 

FIELD: process engineering.

SUBSTANCE: invention relates to construction and mining, particularly, air-operated percussion tools. Percussion mechanism comprises cylindrical case with outlets, circular flange with central through bore, working tool with shank and stepped hammer with rod part. Rod with piston part is fitted in circular flange central through bore to stay permanently in thorough axial bore of stepped hammer. Pneumatic buffer has circular chamber. Cylindrical case bushing has the bore for rod part passage to make a circular web no pneumatic buffer circular chamber side that limits the stroke of steeped hammer. Cup with air feed channel is secured relative to cylindrical case. Circular distribution chamber is arranged in cylindrical case bushing. Circuit air chamber is arranged on circular filter side. Idle stroke chamber is arranged on working tool shank retained by spring relative to cylindrical case. Channels-grooves are made on rod piston part side surface to interact with steeped hammer through axial bore. Said channels-grooves feature variable lengths and total area of cross-sections increasing at area from full diametrical section of rod end part to end part end in through axial bore of stepped hammer.

EFFECT: decreased idle stroke chamber air counter pressure, and resistance to hammer stroke, higher power of impact and impact frequency.

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