An automobile plant in the city of Kremenchug produced simple and reliable trucks with two or three driving axles. Options with rear-wheel drive were widely used in the civil service as flatbed trucks, dump trucks, and chassis for the installation of various construction and road equipment. All-wheel drive cars, nicknamed the "Rapporteurs" for their characteristic wheels, for the most part went to supply the army.
general information
The development of a new model of the EOV-4421 excavator based on the KrAZ-255B for the needs of the army began in the late 70s. At that time, the E-305 version was in production, which was equipped with a fully mechanical drive. Because of this, it had low productivity and a complete lack of reserves for modernization.
The main purpose of KrAZ EOV-4421 was to carry out various earthworks during the construction of defensive structures and positions for troops and command and control posts. In addition, the working boom of the machine can be used to move goods weighing no more than 3000 kg. The maximum height of the work does not exceed 4.5 meters.
The production of cars started at the specialized enterprise "Red Excavator" (Kiev) at the very end of the 70s and lasted about 20 years. Based on the base model, there was an improved modification of the 4421A. After the collapse of the USSR, the production of this machine continued for several more years under the Atek-4421A index.
Operating principle
The main working element of the EOV-4421 is a bucket having a reverse circuit. For the excavator, only one bucket option is available with a maximum capacity of 650 liters. Because of this scheme, work is performed according to an unusual procedure - from top to bottom. All boom and bucket drives are run from hydraulic cylinders and a single high pressure line. The system pump is driven by an additional diesel engine, which is directly connected to the working shaft of the pump. The range of a fixed chassis is only 7.3 meters.
A big minus of the machine is the inability to install a standard straight bucket. Because of this, there are no reserves for increasing the productivity of the EOV-4421. However, the excavator continues to be widely used in many works because of its excellent cross-country ability and cost-effectiveness.
Base chassis
The car is equipped with an eight-cylinder Yaroslavl diesel model 238, which develops power up to 240 forces. The transmission includes a five-speed main gearbox and a two-speed transfer case. Due to the large number of units in the transmission and large wheels, fuel consumption does not fall below 40 liters per hundred kilometers. The fuel supply is stored in two cylindrical tanks and is 330 liters.
When moving to the place of work, the excavator can accelerate to a speed of 70 km / h and overcome pits and trenches no more than a meter wide. This is an acceptable indicator for a large and heavy (weight about 20 tons) machine. The installation cabin does not differ from the truck equipment and is intended for the driver and a pair of passengers.
Optional equipment
On the turntable was an additional four-cylinder diesel model SMD-14, which developed up to 75 forces. The hydraulic system of the EOV-4421 excavator was driven from this unit. To power the engine there was a separate tank, which provided autonomous operation of the installation up to 12 hours. This result is achievable only with the correct adjustment of the equipment for supplying fuel to the cylinders. The standard consumption of diesel fuel when working under load should not exceed 5 liters per hour.
The engine allows you to perform a quick full turn of the excavator platform and dig up to 90 meters of a standard trench in an hour. When excavating pits, an experienced operator can get up to 100 cubic meters of soil per hour.