Patent ID: 7128172

Claim:
A drill string for percussive rock drilling comprising a shank adapter, an extension rod, a starter rod, and a drill bit, all arranged in series; wherein a rear end of the drill bit and a front end of the starter rod are configured for releasable interconnection; a rear end of the starter rod and a front end of the extension rod are configured for releasable interconnection; a rear end of the extension rod being configured for releasable inter-connection with the shank adapter; wherein the shank adapter, the extension rod, the starter rod, and the drill bit are configured for transmitting impact waves and conducting flushing medium; wherein the shank adapter comprises first and second adapter portions, a length of the second adapter portion being 60–140 mm; a front end of the first adapter portion being configured for releasable interconnection with a rear end of the second adapter portion; a front end of the second adapter portion being configured for releasable interconnection with the rear end of the extension rod.