CROWN BIT Russian patent published in 2015 - IPC E21B10/02 E21B10/48 

FIELD: mining.

SUBSTANCE: drill bit comprises the body with working end divided by flushing grooves into sectors reinforced with wear-proof inserts, and damper. The latter is composed of two telescopic flat springs, on one side provided with connection thread for jointing with the crown bit body and core tool and on opposite side, they are rigidly interconnected. Note here that OD of larger diameter springs are reinforced with wear-proof inserts. Inner and outer springs are fitted in place to contact by their side surfaces between themselves. Note also that clearance between facing adjacent spring turn ends at initial position is larger than the spring working stroke initial position but smaller then their lengthwise flanges.

EFFECT: higher efficiency of crown bit operation, mainly, at drilling in interleaving and fractured rock.

2 cl, 1 dwg