Our Extractor Hammers do exactly that. Get that stuck drill string back out of the hole.
The Medium Extractor Hammer (pictured at left) is a pneumatic hammer. The outer sleeve of the extractor is a reciprocating weight that weighs 200 lbs. It cycles fast like a down hole hammer and has a 4 1/2″ API thread at each end. With subs, it can be fastened to the top head drive or kelley of any rig. The sub on the bottom is fastened to the drill rod, casing, or whatever you want to pull.
While the Extractor Hammer is hammering up, the operator can pull up or push down, twisting simultaneously, if desired; normally you need only to pull. The Extractor Hammer has a 4 1/2″ regular box on the bottom.
The Extractor Hammer package includes two subs of the following choices: 3 1/2 API pin up or pin down or 2 7/8 IF pin up or down (with a 6″ pull plug).
Other accessories are threaded casing adapters and the heavy duty hinge that allows the casing or drill pipe to be pulled out away from the rig as the top head is lowered back down.