When carrying out logging work for the removal of sawn trees or whips (trunk with sawn branches), various techniques are used. Material is delivered from logging sites to the place of loading onto timber trucks using skidders. For further transportation in the presence of relatively good roads, all-terrain vehicles with a trailer-dissolution are used.
General information
The most common tracked vehicles with two types of latches - with and without a choker. The first option carries out the movement of previously sawn trunks by drag, and the second one works in tandem with a special installation that cuts the tree and cleans the surface from knots. One of the most common machines is the TDT-55 skidder, which began production back in 1966. The car was assembled at a specialized Onega plant located in the city of Petrozavodsk. Despite the cessation of production in 2003, the tractor remains very popular because of its simple and unpretentious design.
The second most common unit is the TT-4 skidder, which has been produced by the Altai plant since 1991. This machine had a more modern design, but lasted on the conveyor only until 2010. The reason for the cessation of production was the bankruptcy and closure of the plant. TT-4 is a larger machine and belongs to the class of tractors with an effort of 4 tons (versus 2 tons for TDT-55).
Power plants
Both types of tractors are equipped with 4-cylinder liquid-cooled diesel engines. On TDT-55, motors of different types can be found - SMD-14BN, SMD-18N or D-245. Their power is from 62 to 100 forces. Most often there are cars with a SMD-14BN diesel engine and a five-speed gearbox.
The second machine uses a 110-horsepower AM-01 motor with a gearbox that provides eight forward gears and four reverse gears. Between the engine and gearbox on both machines a double-disk clutch is installed.
Chassis
The main part of the TDT-55 chassis is a sturdy frame made by welding from spars. To give greater rigidity, its lower part is covered with a steel sheet, and inside there are additional amplifiers of various shapes. Two suspension balancers equipped with spring shock absorbers are attached to the side parts of the side members. On each of them are placed two steel road wheels. A steel guide roller is installed in front, which can be moved to provide interference to the track of the skidder. To rotate the tracks, a rear wheel is used, equipped with a replaceable gear ring. The caterpillar has fingers floating freely in the seats. These parts are pushed into place by a special finger picker mounted on the drive gear of the drive wheel.
The chassis on the TT-4 has some differences. Its basis is a welded frame, consisting of side spars, which are interconnected by three transverse pipes and a front beam. The frontal sheet and the bottom part give additional rigidity to the frame. The suspension consists of five steel rollers. In this case, only two front rollers on each side have cushioning. The caterpillar is assembled on fingers with a hole for special locking rivets.
Special equipment
The TT-4 has a special winch equipped with a two-stage transmission and a reverse mechanism. Its drive is made from the driven shaft in the transfer case. On the back of the frame is a movable shield, which is used for laying whips. Its design has a special bulge that protects the load from slipping. Removing the shield from the tractor is carried out using hydraulic cylinders. After loading the wood onto the shield, it is pulled to a regular place with a winch.
The equipment of the TDT-55 is similar to the TT-4, with the exception of the hitch. A pushing frame with a blade is installed on the front of the side members of this tractor. A knife is placed along the bottom edge of the blade, which is used to cut soil or shrubs during various operations. The blade position control is hydraulic.
Workplace
On TT-4 the driver is in a fully enclosed two-seater cabin with circular glazing, providing a good overview. The cab is mounted on the axis of the tractor directly behind the engine. The driver's seat is equipped with shock absorption and can be adjusted in height. On the TT-4M version, a single cabin is used, offset to the left side.
A single cabin TDT-55 is located on the left side of the tractor. Next to it is an engine closed by a hood. Ventilation and heating systems with fan air supply are standard equipment. In the summer, you can provide additional air exchange using moving windshields and side windows. There are cleaners on the front and rear windows. The driver's seat can be adjusted in height.