Trip hammer

Early history

China

  In ancient China, the trip hammer evolved out of the use of the Du Shi)(Wade-Giles spelling):

Fu Hsi invented the pestle and mortar, which is so useful, and later on it was cleverly improved in such a way that the whole weight of the body could be used for treading on the tilt-hammer (tui), thus increasing the efficiency ten times. Afterwards the power of animals—donkeys, mules, oxen, and horses—was applied by means of machinery, and water-power too used for pounding, so that the benefit was increased a hundredfold.^[4]

With his description, it is seen that the out-of-date Chinese term for pestle and mortar (dui, tui) would soon be replaced with the Chinese term for the water-powered trip-hammer (Pinyin: shui dui; Wade-Giles: shui tui).^[2] The Han Dynasty scholar and poet Ma Rong (79–166 AD) mentioned in one of his poems of hammers 'pounding in the water-echoing caves',^[4]. As described in the Hou Han Shu, in 129 AD the official Yu Xu gave a report to Emperor Shun of Han that trip hammers were being exported from Han China to the Western Chiang people by way of canals through the Chilian Shan Mountains.^[4] In his Rou Xing Lun, the government official Kong Rong (153–208 AD) remarked that the invention of the trip hammer was an excellent example of a product created by intelligent men during his own age (comparing the relative achievements of the sages of old).^[4] During the 3rd century AD, the high government official and engineer Du Yu established the use of combined trip hammer batteries (lian zhi dui), which employed several shafts that were arranged to work off one large waterwheel.^[5] In Chinese texts of the 4th century, there are written accounts of men possessing and operating hundreds of trip hammer machines, such as the venerable mathematician Wang Rong (died 306 AD), Deng Yu (died 326 AD), and Shi Chong (died 300 AD), responsible for the operation of hundreds of trip hammers in over thirty governmental districts throughout China.^[6] There are numerous references to trip hammers during the Tang Dynasty (618–907 AD) and Song Dynasty (960–1279), and there are Ming Dynasty (1368–1644) references that report the use of trip hammers in papermills of Fujian Province.^[7]

Although Chinese trip hammers in China were sometimes powered by the more efficient vertical-set waterwheel, the Chinese often employed the horizontal-set waterwheel in operating trip hammers, along with recumbent hammers.^[8] The recumbent hammer was found in Chinese illustrations by 1313 AD, with the publishing of Wang Zhen's Nong Shu book on ancient and contemporary (medieval) metallurgy in China.^[9] There were also illustrations of trip hammers in an encyclopedia of 1637, written by Song Yingxing (1587-1666).^[10]

Europe

The first known water-powered and mechanised trip hammers in Europe were found by the 12th century. Their use was described in medieval written sources of Styria (in modern-day Austria), written in 1135 and another in 1175 AD.^[11] Both texts mentioned the use of vertical stamp mills for ore-crushing.^[11] Medieval French sources of the years 1116 and 1249 both record the use of mechanised trip hammers used in the forging of bloomery furnace.^[9] Although illustrated in China beforehand in the early 14th century, the recumbrent hammer was first depicted in artwork of Europe by the 17th century, in an illustration by Sandrart and Zonca (dated 1621 AD).^[9]

Types of trip hammers

Trip hammers were of three kinds. All require artificial power to lift them:

• The tail helve hammer or 'tilt hammer' has a pivot at the centre of the helve on which it is mounted, and is lifted by pushing the opposite end to the head downwards. In practice the head on such hammers seems to have been limited to one hundredweight (about 50 kg), but a very rapid stroke rate was possible. This made it suitable for drawing iron down to small sizes suitable for the cutlery trades. There were therefore many such forges known as 'tilts' around Sheffield. They were also used in brass battery works for making brass (or copper) pots and pans. In battery works (at least) it was possible for one power source to operate several hammers.

• The belly helve hammer was the kind normally found in a pig iron into forgeable bar iron. This was lifted by cams striking the helve between the pivot and the head. The head usually weighted quarter of a ton. This was probably the case because the strain on a wooden helve would have been too great if the head were heavier.

• The nose helve hammer seems to have been unusual until the late 18th or early 19th century. This was lifted beyond the head.

The choice of which kind should be used in a particular context may depend on the strain that its operation imposed on the helve. This was normally of wood until the 19th century. Surviving nosehelves^[12] and those in pictures^[13] appear to be of cast iron. This was replaced by James Nasmyth's steam-powered drop hammer (invented in 1839 and patented in 1842. However the forge had become less important following the improvements to the rolling mill that went along with the adoption of puddling from the end of the 18th century.

Notes

References

• Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 2. Taipei: Caves Books Ltd.
• Song, Yingxing, translated with preface by E-Tu Zen Sun and Shiou-Chuan Sun (1966). T'ien-Kung K'ai-Wu: Chinese Technology in the Seventeenth Century. University Park: Pennsylvania State University Press.