Rake
The rake (South German also: Schlagler ) is an agricultural device that is used to combine crops such as hay or straw into uniform (night) swaths (locally also loading discs, rows, lines, oars, harrows, slaughtered meat). These can then be picked up with the baler , a forage harvester or a loading wagon . In addition, the wilted material is also brought into this shape in the evening so that it is better protected from the nocturnal dew and the soil can dry better in the morning before the stalks are then evenly distributed again with the hay tedder so that they can continue to dry.
Types
There are many different types of rake. The devices not described here are multiple devices and are shown in the article about hay tedders . Most of the rakes are mounted in the rear, all types can also be found occasionally in the front. Modern large swathers have their own chassis and are attached.
Rotary rake
The rotary rake is the most common. It has one or more horizontal rotors with 6 to 16 tine arms, which are driven by the tractor via the PTO or the hydraulics. Several rake tines are attached to the arms, which brush vertically over the ground and transport the crop to the side with one, two or three rotors or to the center with two, four or six rotors. The tines are deflected and the stalks are deposited via a cam track control. The swath can still ventilate through the loose deposit. The large rotors of up to 4.50 m make adaptation to the ground more difficult, but this can be improved by tandem chassis under and jockey wheels in front of the rotors. By combining two, four or six rotors, working widths of up to 20 m can be achieved. The working speed is around 8-15 km / h. In some designs with side swath placement, the rotors can be adjusted so that two swaths are placed. This function is mostly used to rake up arid crops overnight ( night swaths ).
Star wheel rake
It consists of 3–20 toothed wheels, the so-called star wheels, which push the stalk from one star to the other at an angle to the direction of travel and deposit it as a swath. The spring-mounted, ground-driven star wheels follow the ground well and handle the crop very gently. However, the work performance decreases with heavy and wet forage.
The star wheel swathers are available as side swathers that deposit the swath to the side and as central swathers with a working width of almost 12 m. The newer small devices are attached to the three-point hydraulic system . All others are drawn. The larger devices also have an articulated frame, which further improves ground contour following. Due to the much higher possible working speed (v> 20 km / h), the work performance is significantly higher than that of rotary swathers of the same width. The acquisition and operating costs are lower than with rotary rakes due to the simpler construction. The introduction of the star wheel turner at the beginning of the fifties in the last century was a milestone in the development of new techniques for rationalizing the forage harvest . While the star wheel rake has lost importance in Germany with the development of the rotary rake, it is popular and widespread in other countries, especially in North America. A colloquial name is "Heuma", a brand name of the Niemeyer company. The star wheel swather is charged with weaving the swath into a braid, which makes it much more difficult to pick it up later.
Swath discs work according to the same principle . On rotary mowers , they serve to shift the forage by a few centimeters so that it is not run over. When pressing one uses it when the swath slightly wider than the pickup is.
Rotor rake
The rotor swather has several horizontal rotors with the same direction of rotation. With tines attached parallel to the surface of the ground, it transports the crop across the direction of travel and deposits it on the side. Due to the limited working width, it was hardly of any importance. An example is the CZ series (e.g. CZ 330, CZ 330-CH, CZ 340, CZ 450 and CZ 600) from PZ (Piet Zweegers). These have working widths of 3.3 to 6 m. The great advantage of the PZ CZ series was the high possible driving speed (20 km / h are possible at the appropriate speed), the low demands on the tractor (weight as well as power) and the swath is very airy. Disadvantages are the forage contamination on wet ground, the poor ground contour following of the wide models (especially the CZ600) and, at high driving speeds, the not very gentle forage treatment due to the high speed. Where these rakes are still used quite often is in numerous standard fruit trees. The reason for this is that you can drive very close to fruit trees with a rotor rake without damaging the rake if it comes into contact with the tree.
Another representative was Kuhn with the Kuhnflex rake and Deutz-Fahr with the TS 3.35. No tines were used for this, but rather rubber flaps with, in practice, quite high wear. At the same time, these rakes were often even more aggressive and less popular. However, if the setting is extremely meticulous and the ground is level, these rakes allow good swathing results, but they react very strongly to uneven ground.
In general, rotor rakes are no longer manufactured and there is hardly any demand for them anymore.
Pick-up belt rake
These rakes take the conveyed via pickup and transport the material onto a conveyor belt. This moves across the direction of travel and places the swath on the desired side. In contrast to rotary rakes, the forage is not swept over the ground. This prevents it from becoming dirty after the exposure.
Comb swather
In this long-standing design, there are combs that are inclined to the direction of travel. Around 10 combs rotate similar to the reel on a combine harvester and thus transport the grass. As a special feature, the rake is hydraulically driven.
Belt rake
Band rake swathers (also called band hay rakes or band rakes) have chains running transversely to the direction of travel, on which tines are mounted vertically. Their low demands on the towing vehicle make them particularly interesting for mountain regions, as a belt rake is very close to the vehicle and there is therefore no risk of axle relief. In addition, the performance requirements are very low, so that a hydraulic drive is also possible in addition to the conventional drive via the PTO shaft.
There are versions for front attachment or rear attachment with two devices (especially from Sepp Knüsel), so that a working width of around 5 meters is achieved; A baler or a loading wagon usually follows in the rear attachment. At the same time, there is also a conveyor belt for attaching the side to a transporter . These are driven hydraulically.
This type of rake is often also attached to a motor mower , especially on steep slopes.
literature
- Agriculture: Volume 3 - Agricultural engineering and construction . BLV Verlagsgesellschaft, Munich, ISBN 3-405-14349-7 .
- Udo Bols: Agricultural implements for tractors in earlier times . Verlag Podszun-Motorbücher GmbH, Brilon, ISBN 978-3-86133-441-5 .
