tilt hammer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A heavy forge hammer having a pivoted lever by which it is tilted up and then allowed to drop.

from The Century Dictionary.

• noun In mech., a power machine-tool for hammering, forging, etc.

from the GNU version of the Collaborative International Dictionary of English.

• A tilted hammer; a heavy hammer, used in iron works, which is lifted or tilted by projections or wipers on a revolving shaft; a trip hammer.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tilted hammer; a heavy hammer, used in ironworking, lifted or tilted by projections or wipers on a revolving shaft; a trip hammer.