Since wood has become a necessary raw material for human society, in addition to firewood and weapons, for the construction of housing, subsequent buildings and other products for various purposes, the forest has become a source natural inexhaustible wealth and raw materials. One of the fundamental problems that arose was the extraction or transport of the fallen log from the forest to the workshop or to the construction site.
In the forest exploitation, mechanization is becoming more and more important every day. Attachments and log grapples belong to the group of construction machinery and are used to easily extract fallen trees and finished logs from inaccessible forest terrain, an accessible path or warehouse from which logs can be easily transported by conventional means of transport. For this purpose, it is equipped with devices and tools for receiving and towing or transporting logs.
There are three methods of attracting wood:
- ground traction (cattle, adapted agricultural tractor or skidder),
- export on wheels (tractor – crew or forwarder combination) and
- to take away (forest cable car or helicopter).
Mechanization of development and working technique, the process of obtaining wood is faster and raises the safety of workers to the highest possible level. In any case, foresters generally choose the first solution because it is the simplest. If you are wondering if you need a machine like this, read some information about it that will help you make a choice.
1.4 × 4 drive
Due to the inaccessible terrain, wood clamps have four-wheel drive, and unlike conventional tractors where the front wheels are smaller, these machines have four equal wheels. When pulling the timber, the raised end of the load rests on the rear of the skidder and the dynamic loads of the front and rear axles are equalized or, depending on the position of the timber in the load, the size of the loader. load and slope, the loads on the rear axle are higher.
The limit load that the skidder can attract is therefore determined by the admissible load on the rear axle, the angle of longitudinal stability and the achievement of the traction force on the wheels.
The propulsion part consists of an internal combustion engine, most often a four-stroke diesel engine. The transmission system transmits power from the engine to all wheels. The purpose of the power transmission system is to increase the torque obtained on the wheel. By studying the current development and production of these around the world, it is concluded that most loggers and other similar machines use a mechanical transmission. The transmission system consists of a clutch, gearbox, drive distributor, differential on each axle, and planetary or end gear on each wheel.
3. Technical characteristics
The weight of logs for extracting and transporting logs is approximately 7 tonnes (60% on the front axle and 40% on the rear axle). Timber grapples are becoming more and more massive, and the reasons are in the demands for increased productivity, their application and their durability. The transmission is usually with 5 forward gears and 1 reverse with fast and slow speed.
Although log handles are made of durable materials, they do sometimes break. Even if this happens, don’t worry, it can be replaced. This is very useful to know because on a machine you can change the handles according to your needs. Learn more about it on uniforest.de.
4. Working techniques
The movement of machines in the forest is only allowed on pre-marked or constructed forest roads. Adjacent trees along the road must be properly protected from damage. Machines must be used in such a way as not to damage adjacent shafts. The weight of the load and the carrying capacity of the land must always be taken into account. Overloading causes excessive compaction of the soil and also damages the veins and roots of surrounding trees.
Timber removal is mainly related to rugged and inaccessible mountainous areas, where, due to large differences in height over short horizontal distances, the construction of forest roads is expensive and environmentally unacceptable. When removing the timber, the round timber is completely or partially lifted off the ground, which causes less damage to the soil and young shoots along the cable car route and as such is an environmentally appropriate procedure.
5. Safety when working with forestry machines
When pulling wood sets, workers and other persons should not be on the tow rope or driving with the driver, on the tractor or on the wood sets that are being drawn. In order to avoid risks when working in groups, the operator of the machine should not start to attract wood sets until the assistant has given them the intended start signal. The worker who manages the mechanized means must be trained to attract logs, roundwood and other assortments of wood.
In unfavorable weather conditions (rain, wind, snow, cold, etc.), the attraction of wood assortments can only be achieved with a machine equipped with a safety cabin with driver’s seat. The tractor with cab must be easy to mount or remove from the cab. The tractor cab must be designed to protect the driver or front passenger if two seats are installed in the cab, inclement weather, drops and overhead branches, lumps of logs and other objects, injury from overturning the vehicle. tractor, etc.
Forestry today can in no way be compared to forestry at the start of the last century. Global forestry is based on short patrol forests, forest plantations and crops in which clean logging is carried out and high-tech mechanization, such as that which is an example of joint work: harvester – forwarder where they combine logging and wood production and export of felling sets.
Due to the extreme risk when working with machines on forest land, it is important to strictly control the accuracy of the wood clamps and to maintain them properly. Although evolutionary mechanization has improved and accelerated the work of obtaining wood, there remains a human factor necessary for good logging. That is why it is extremely important to train workers and to promote and respect the standards of safety and protection of workers engaged in forestry affairs.