Tedders are an important and vital agricultural equipment used for haying on large livestock farms and private farmsteads. The popularity of the equipment is due to its high performance and ease of use.
Device and purpose
Tedder rakes replaced the usual rake, which was used to rake grass after mowing. With their appearance, it was possible to mechanize the process of harvesting hay and completely eliminate the use of heavy manual labor. Structurally, the rake-tedders are a two-section wheel-finger construction in which the sections are able to work both together and separately. Each block consists of a frame, support wheels and rotating rotors, which are the main working parts of the unit. The rotors are mounted to the frame by means of tapered bearings, and the torque required for their rotation is transmitted using the tractor universal joint shaft. The support wheels come into motion due to adhesion to the ground during the movement of the tractor.
Each of the rotors is equipped with raking fingers, for the manufacture of which high-strength steel is used. Depending on the model, the number of rotary fingers can be different - from 32 to 48 pieces. The fixing of the rotor wheels is carried out by means of a spring suspension, which prevents mechanical damage to the working elements and extends the service life of the unit. The rotors are located at a certain angle with respect to the line of movement of the tractor, and thanks to the rotating adjusting lever, they can be raised or lowered to the height necessary for more efficient operation. The same lever is used to put the unit into transport mode, when the rotors are raised high above the ground so as not to damage during movement.
Tedder rakes perform 3 important functions at once. The first consists in raking the mowed grass stand, the second in turning over already dried grass, which prevents its over-ripening, and the third in the formation of neat rolls convenient for transportation and storage.
Principle of operation
The process of swathing with a rake-tedder rake is quite simple and consists in the following: the movement of the unit in the field is carried out thanks to the tractor, which can be either a conventional tractor or a mini-tractor. The rotor wheels begin to rotate, while their fingers rake the mowed grass in such a way that the grass captured by the first rotor is pulled slightly to the side and transferred to the second and subsequent wheels. As a result, after passing the grass through all the rotors, uniform and voluminous rolls are formed, each of which is already well loosened and breathable. This grass collection technology allows hay to dry quickly and not overheat. The width of the rolls can be adjusted using the front and rear stretch marks.
The next function of the unit - tedding of hay - is as follows: the angle of the rotors relative to the ground is slightly altered, because of which the grass collected with the fingers does not enter the next wheel, as it was in the previous case, but fluffs and remains in the same place . The overturning of dried grass is achieved by advancing the unit section along the formed roll, which at the same time moves slightly and turns over. The operation of the rake-agitator is carried out by one tractor driver, and due to the simplicity of the design and the absence of complex components and assemblies, repair and replacement of failed parts can be performed in the field.
Advantages and disadvantages
As with any agricultural equipment, rake tedders have their pros and cons. The advantages include the unpretentiousness of the equipment in operation, as well as its undemanding to routine maintenance. A long service life of units reaching ten years is also noted. In addition, we can note the high reliability and durability of the structure, the basis of which is a powerful drawbar and a strong frame, as well as the ability to conveniently adjust the position of the rotors and quickly switch to the inoperative position, which is achieved thanks to the hydraulic mechanism. The performance of the rake tedders varies by model and averages 7 ha / h.
The disadvantages include the slow operation of the equipment in the corner sections, as well as the not very reliable chassis. However, the latter problem is a drawback of most trailed agricultural implements for various purposes.
The classification of rake-tedders occurs according to several criteria.
- Type of tractor. On this basis, two categories of aggregates are distinguished, the first of which is presented in the form of mounted or trailed equipment for tractors, and the second is much smaller and is intended for walk-behind tractors.
- The method of swathing. According to this criterion, two groups of devices are also distinguished: the first ones provide lateral, and the second ones provide lateral roll formation. Moreover, the "transverse" models have a very large grip, reaching 15 meters.
- Design. There are three types of tedders rakes on the modern market: wheel-finger, drum and gear. The former are equipped with a rotary wheel cushioning system, which makes them an indispensable type of equipment when working in fields with difficult terrain. Drum models are strong and durable devices, the principle of which is based on the rotation of independent from each other rings. Gear units are driven by a gear train and are capable of changing the angle of rotation and the inclination of the teeth.
- The number of rotor wheels. The most common type of equipment is four- and five-wheel models.
Four-wheel tedders are designed to work with tractors with a capacity of 12 to 25 liters. with. and walk-behind tractors. The tedding width of such models is 2.6 m, and the grass capture width is 2.7 m. Such devices weigh about 120 kg and are capable of operating at a speed of 8 to 12 km / h.
Five-wheeled samples of agitators aggregate with any type of tractor, excluding low-power walk-behind tractors. They have slightly higher performance when compared with the previous view. So, the length of the structure reaches 3.7 m, and the rotors are located obliquely. This design allows you to increase the efficiency of tedding and to eliminate losses during raking of grass. The weight of the models is 140 kg, the working speed is 12 km / h.
In addition to those presented, there are two-wheeled models, one of which will be discussed below.
The domestic agricultural equipment market is represented by a large number of rake-tedders. Among them there are both foreign units and devices of Russian production.
The most popular of them is the GVK-6 model. The product is manufactured at the enterprise of correctional institution No. 2 of the city of Ryazan and is actively exported to neighboring countries. The equipment can be aggregated by means of wheeled tractors of classes 0.6-1.4 and mounted on them like an ordinary hitch. A feature of the GVK-6 tedder is its ability to work with raw grass, the moisture content of which reaches 85%. For comparison, Polish and Turkish counterparts can only cope with 70% humidity.
The length of the unit is 7.75 m, the width is 1.75 m, the height is 2.4 m, and the working width reaches 6 m. The roll width is 1.16 m, the height is 32 cm, the density is 6.5 kg / m3, and the distance between two adjacent rolls is 4.46 m. In the working position, the device is able to move at a speed of up to 12 km / h, and during transportation - up to 20 km / h. The GVK-6 model is characterized by high productivity and processes an area of up to 6 hectares in an hour. The weight of the rake is 775 kg, the cost of one section is 30 thousand rubles.
The next popular model GVR-630 comes off the assembly line of the Bobruiskagromash manufacturing plant. The unit is also used in the form of a tractor trailer, and is connected to the tractor by means of a hydraulic system and a power take-off shaft. The working unit of the device is of Italian origin and is presented in the form of an asymmetric collapsible frame with two rotors installed on it. Each rotor has 8 rake mounted on it with a hub. Each rake is equipped with six teeth located at right angles. The height of the rotors above ground level is regulated by means of a hydraulic drive located on the left rotor wheel, which allows the robbery of fields with a slope and complex terrain.
The principle of operation of this model is somewhat different from the principle of operation of models of other brands and consists in the following: with multidirectional rotation of the rotor wheels, the teeth collect the mowed grass and lay it in rolls. When the direction of rotation changes, the machine, on the contrary, begins to stir up the mowing, thereby increasing air exchange and accelerating the drying of grass. The model has a large working width of up to 7.3 m and high raking performance of 7.5 ha / h. This is 35% higher than the average of most other models. In addition, the device is very maneuverable and compared with other models can reduce fuel consumption by 1.2 times. Such a rake weighs 900 kg, and their cost is within 250 thousand rubles.
You should pay attention to the swather GVV-6A produced by the Bezhetskselmash plant , located in the Tver region. The model is highly appreciated by Russian and foreign farmers; it competes worthily on the modern market with Western models. The unit is capable of processing 7.2 hectares per hour and has a rather high working speed of 14.5 km / h. The width of the device is 6 m, and the roll width when raking is 140 cm. The weight of the device reaches 500 kg, the cost is about 100 thousand rubles.
When working with a rake-tedder, a number of recommendations should be observed.
- Attach equipment when the tractor engine is off.
- Before starting work, it is necessary to check the connection of the rake and the tractor, as well as the presence of a safety cable fixed to the tractor cross member. You also need to make sure the tightness of the hydraulic system and the health of the driveshaft.
- During stops, the gear lever must be put in a neutral position and the power take-off shaft (PTO) must be turned off.
- It is forbidden to leave the tractor with the engine and PTO on, as well as with the parking brake off, unattended.
- Adjustment, cleaning and maintenance of the tedder rake should be done only with the tractor engine turned off.
- At bends and difficult terrain, the rake speed should be reduced to a minimum, and with especially sharp turns, it is necessary to disconnect the PTO.
See how the rake tedders work in the next video.