Scissors (textile finishing)

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Shearing (ancient scissors , English shearing ) is a finishing process in the textile industry . By cutting off protruding fiber ends (the pile ), a uniform surface is created after the loop structure of these textiles has been cut or the fabric or possibly knitted fabric has been roughened .

history

It is not known when shearing, which used to be used for the finishing of cloth, came into being. A prerequisite for this was the existence of hanger shears , which can be proven several times in the last millennium BC. The oldest, very vague references to shearing can be found around 400 BC. The evidence for the implementation of this procedure in the time of the Romans is much more concrete . Finds of fragments of cloth scissors in the northern provinces as well as representations on grave steles show that shearing was carried out in Roman times. Around a millennium later, a picture of a 14th-century clipper can be found on the glass windows of the cathedral of Semur-en-Auxois / France. When shearing emerged as an independent craft cannot be determined. The first indications are found in Florence in 1193 . In Germany, this craft can be traced back to Augsburg for the first time in 1346 . Attempts were made early on to mechanize shearing. Leonardo da Vinci carried out the first work on this around 1500. He designed a mechanized cutting table. After him, another technology visionary, Christopher Polhem , dealt with this topic. After the first works by Leonardo, it took around three hundred years before the time was ripe for their realization. The Englishman John Harmar from Sheffield was the first to take up the idea of ​​the mechanized cutting table again and in 1787 created a corresponding mechanical device. This was in use for several decades. It was replaced by the rotary knife shearing machine . The machine, the working principle of which is still used today, goes back to the American Samuel Grissould Dorr from Albany , who registered a patent for a machine of this type in 1792. By the middle of the 19th century, the mechanized shear table had largely been replaced by the rotary knife shearing machine in textile finishing companies.

Cloth shearers shearing in the 16th century

Hand shears

Before the introduction of the machines, shearing was done manually with large cloth scissors on shear tables. The cloth scissors were heavy ironing scissors with a total length of 100 to 140 cm. The two cutting surfaces, which came together in a bracket, had lengths of approx. 60 cm. Work was carried out on long, narrow cutting tables approx. 3 m long and 40 cm wide. A padded fabric was stretched across the surface of the table so that it was slightly curved . The tissue to be sheared was attached to these tables with so-called cloth shear clips or pin hooks .

Mechanical shearing

Today shearing is done with a clipper or diagonal clipper. Pioneering work in this area was done by Severin Heusch in Aachen in 1850 and thus the oldest shear knife factory in Germany, primarily through the development of his "Heusch concave spiral", a shear knife whose main advantage was that its cutting angle changed over the course of the material Wear process no longer changes. Before the industrial revolution , this work was done by the cloth shears with large hand shears .

application

The shearing production step produces various semi-finished textile products :

Pattern formation in tufted carpets

For special effects, loop carpets are also subjected to the shearing procedure and thus patterned. A distinction is made between the following shear methods:

Tip-sheared ('shearing the tips')

With this shearing method, the shearing knife is set to a certain height and shears off the longest poles of the carpet, so that a cut pile is created at this point and the shorter poles remain, the loop pile remain. If the pile consists of three pile heights, the middle height is shorn. In the method, only the top section of the pole is sheared.

Random-sheared: ('random shear')

With this method of shearing, the loop pile is initially tufted with higher loops as if by chance in order to shear off the higher poles in the actual process. A random pattern arises. You can only shear the poles.

Level-sheared: ('scissors at height')

This method is tufted at two heights and the higher pole is completely cut open, which can create two different surfaces. At the end there is a uniform height. Loops and velor are on the same level.

literature

  • Daniel Gottfried Schreber u. Henri Louis Duhamel du Monceau: The art of cloth making, primarily in fine cloth. Leipzig, 1776, OCLC 174761934 .
  • Julia de Lacy Mann: The Cloth Industry in the West of England from 1640 to 1880. Clarendon Press, Oxford, 1971, ISBN 0-19-828255-9 .
  • Herbert Vogler: Who Invented the Clipper? In: Melliand textile reports. Year 1989, 2008, pp. 39–43.

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