Trip hammer
（重定向自Helve Hammer）
A trip hammer, also known as a helve hammer, is a massive powered hammer used in:
Trip hammers were usually raised by a cam and then released to fall under the force of gravity. Historically, trip hammers were often powered by a water wheel, and are known to have been used in China as long ago as 40 BC or maybe even as far back as the Zhou Dynasty (1050 BC–221 BC) and in medieval Europe by the 12th century. During the Industrial Revolution the trip hammer fell out of favor and was replaced with the power hammer. Often multiple hammers were powered via a set of line shafts, pulleys and belts from a centrally located power supply.