Bar mower

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Motor mower with double knife cutter bar with fixed counter knife (communal cutter bar)
Details of a finger cutter bar
Detail of a double knife cutter bar with two driven knives, i.e. a movable counter blade
Cutting unit with finger cutter bar on a combine harvester

A mower is a mower for mowing of grass , grain or thin trees. The special feature of this agricultural machine is the beam on which the cutting device is attached. The plant material to be mowed is cut according to the scissor-cut principle by the oscillating movement of a knife bar equipped with triangular knife blades against a fixed or movable counter blade. For a flawless cut, a cutting speed (i.e. the speed of the knife bar to the shearbar) of an average of 2.4 m / s for grass and of around 1.75 m / s for the harder stalks of harvested grain is required. The drive can be done by ground drive of the device pulled by draft animals or tractors or direct drive by the engine of a carrier vehicle, for example a tractor or two- wheel tractor .

history

The device described by Pliny

Pliny the Elder reports in his natural history of a mower for grain, which is in use in Gaul . A representation of such a mower can be seen on the grave relief in the Musée Gaumais by Virton , another fragment in the Landesmuseum Trier . It shows a donkey pushing a two-wheeled box across a field. The drawbar was attached to the back of the box and behind the animal a farm worker usually walked to steer the device. The box, which was open at the front, had a row of gripping teeth at the level of the ears (but not yet movable against each other). If the device was pushed over a grain field, the ears of corn got between the gripping teeth and fell into the box. The straw stopped and was grazed by the cattle.

“Tolemache mower” from the magazine Die Gartenlaube from 1853
Grass mower with attached hand rest, converted for mowing grain

The first mower for harvesting grain was built in 1826 by the Scottish pastor Reverend Patrick Bell. It already had a reel and moving knives that worked on the principle of scissors. In 1831 Cyrus Hall McCormick built a grain mower, which he applied for a patent in 1834. This "Virginia Reaper" was already equipped with fingers and a knife and brought its inventor great economic success. But it was only with the development of the triangular blades a few years later that the mowing of the finer grass became possible. In 1851 a grass mower was presented in London. Since it was relatively expensive in relation to the labor force, it was not able to establish itself significantly in Europe. Only with the migration of workers into industry was there an increased demand for mowing machines, but as the farms were equipped with tractors, they were replaced by attachable mid-mounted mowers. With the development of the rotary mowers from 1963 and the increase in the performance of the tractor, the importance of the bar mower for grass mowing declined.

The drive power of the bar mower is lower than that of other mowers, but it is still so high that a draft animal is rarely enough or only with a small working width.

Types

The double knife cutter bar has two sharp blades. It prevailed mainly in municipalities and on single-axle mowers with small farmers, on wide-track two-axle mowers only on slopes. The advantage of this technology lies in the largely trouble-free (blockage-free) operation, which, however, is paid for with meticulous adjustment and higher maintenance costs. In the case of stored grass and grain areas, however, the desired cutting quality is not achieved. A distinction is made between:

  • Double cutter bar with one fixed and one moving cutter bar. Mainly used as a universal cutter bar in municipal field maintenance.
  • Double cutter bar with two moving knife rows, used as a grass mower on single-axle tractors and two-axle tractors for mowing.

The finger cutter bar has sharp blades that are guided past the blunt fingers and thus cut off the grass and grain stalks precisely. The finger cutter bar is the most common mowing technology for bar mowers in agriculture. It is much less sensitive to stones or other obstacles than a double cutter bar. At the same time, maintenance is much easier as there are fewer moving parts.

Types

mower

Bar mower for horse-drawn trains, driven by the wheels

For a long time, the mower was pulled by workhorses, and the mower was driven by the wheels across the ground. Because of the difficulty of moving, two horses were necessary, which had the necessary tractive effort. As a result, it remained unaffordable for smaller farmers with a horse for a long time, unless they teamed up with a colleague. It remained a dream for farmers with working cows. It was only with the development of light petrol engines in the 1920s that it became possible to modify the mower. An add-on motor took over the mower blade drive and a horse now only had to pull the mower, which had recently been fitted with ball bearings. Over time, tractors were used as towing vehicles. The era of mowers came to an end in the 1950s after around 100 years of construction.

Attachment mower

Bar mower on a tractor

Equipping the tractors with power take-offs such as a power take-off shaft or mower crank enabled the use of attachment cutter bars. The so-called inter-axle attachment became standard here. Here the mower is attached to the right between the axles. With the invention of the loader wagon in 1961, which was then built to swivel, it was possible to mow and load the grass in one operation. This revolutionized the daily fetching process. Larger working widths of a little over 2 m are designed as rear extensions. Double-knife mowers are mostly used for front attachment because of their more reliable operation. However, they could not prevail because of the poor overview.

Motor mower

The history of motor mowers began in the summer of 1920 when the Swiss farmer's son Jacob Fahrni developed a motor-driven hand-operated mower. In patent specification 99455 from January 12, 1922, he applied for a patent for his idea of ​​the motor mower. The Rapid Motor mower AG took from 1926 the first mass-produced motor-driven mower on the market. Machines with a working width of 2 m were already in use in 1930. With the development of the swath formers at the beginning of the 1950s, the rapid rise of motor mowers in the Alpine region began. The low center of gravity made it possible to use it on steep slopes. It developed into a single-axle tractor to which other machines such as haymaking or transport equipment could be attached. Transporters are a further development of the motor mowers after they had become heavier and heavier and steering forces for the turntable steering were hardly available.

Areas of application

Mounted mowers are still used today in businesses that fetch green fodder for their animals every day. Walk-behind motor mowers are used in areas that are inaccessible to modern technology. They are indispensable, especially in impassable mountains and on poorly bearing or wet surfaces. This particularly appeals to mountain regions such as the Alpine region. This can also be illustrated as a percentage. 22.9% are in Bavaria, 20.5% in Baden-Württemberg and 12.2% in North Rhine-Westphalia. As part of ecological agreements, they can be promoted due to the low risk of injury to the wildlife in the meadows.

Cutter bars continue to be used in combine harvesters , where weight and reduced power consumption are more important than a clean cut.

literature

  • Hans Schön: Agriculture: Volume 3 - Agricultural engineering and construction. Process engineering - work - building - environment , BLV, Munich 1998, ISBN 3-405-14349-7 .
  • Udo Bols: Agricultural implements for tractors in earlier times . Podszun engine books, Brilon 2007, ISBN 978-3-86133-441-5
  • Vogel: About mowers . In: Volksblatt . A weekly magazine with pictures. Year 1878, No. 18, pp. 137–138.
  • Friedrich Georg Wieck: From the commercial world: The mower . In: The Gazebo . Issue 33, 1853, pp. 358-360 ( full text [ Wikisource ]).
  • Mower . In: Meyers Konversations-Lexikon . 4th edition. Volume 11, Verlag des Bibliographisches Institut, Leipzig / Vienna 1885–1892, pp. 100–101.

Web links

Commons : Bar Mower  - Collection of pictures, videos and audio files

Individual evidence

  1. ^ Schweigmann: The agricultural machines and their maintenance . Giessen 1955, p. 176 ff.
  2. Naturalis_historia: 18.72
  3. Currently not on display.
  4. Propylaea Technology History - Agriculture and Crafts - 750 BC Until 1000 AD . P. 213 ff.
  5. NZZ , April 17, 2018, p. 26
  6. Ruedi Struder: 50 years motorization in the mountain economy . ( Memento of November 3, 2013 in the Internet Archive ; PDF) accessed on October 31, 2013
  7. D. Van de Poel, A. Zehm: The effect of mowing on the fauna of the meadows - A literature evaluation for nature conservation . In: ANLiegen Natur , 36 (2), 2014, pp. 36–51, Laufen.