PNEUMATIC PERCUSSION MECHANISM Russian patent published in 2016 - IPC E21B1/30 E21C37/22 

FIELD: construction.

SUBSTANCE: invention relates to construction and mining industry, in particular to pneumatic shock action devices. A percussion mechanism comprises a cylindrical housing with discharge channels, a ring flange with a through central hole, a working tool with a shaft, a step drummer with a stem part, a rod with a piston part installed in the central hole of the ring flange, which is constantly located in the through axial hole of the step drummer, a ring chamber of the pneumatic buffer (stroke), a bushing of the cylindrical housing with a hole for passing of the stem part and the ring neck (formed by the bushing from the side of the ring chamber of the pneumatic buffer - stroke) limiting the size of movement of the step drummer, a barrel with a channel for air intake fixed with reference to the cylindrical housing, a ring distributive chamber in the bushing of the cylindrical housing, a network air chamber from the ring flange side, an idling chamber from the side of the shaft of the working tool held by a spring with reference to the cylindrical housing. Flat channels on the side surface of the piston part of the rod interacting with the through axial hole in the step drummer are implemented with varying lengths with the total area of cross sections increasing from the full diametrical section of the face part of the rod towards the end of the face part installed in the through axial channel of the step drummer. Implementation of the flat channels with varying geometrical sections allows to reduce air counter-pressure in the idling chamber, due to the smaller amount of air the initial stage of intake, through the smaller through passage section of the flat channels that reduces resistance to movement of the step drummer, and also keeps its pre-shock speed to the moment of impact onto the shaft of the working tool, thus increasing the energy of impact and the frequency of impacts of the pneumatic percussion mechanism.

EFFECT: design improvement.

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