DYNAMIC HAMMER Russian patent published in 1996 - IPC

FIELD: devices for recovery of casings from wells, for example, from water wells. SUBSTANCE: dynamic hammer has body connected with its upper part to block and tackle system of drilling rig, striker spring-loaded relative to the body, side rests spring-loaded relative to the body and having limit actuating forces regulated by springs, and cap which is installed on casing to be recovered and serves as anvil. EFFECT: considerable reduction of labor input in recovery of metal casings from wells, decreased energy consumption and economically efficient. 1 dwg