Dump Trucks

Today, it is hard to imagine modern construction without dump trucks, which rightfully belong to the category of road construction machinery. However, not everyone knows that the history of domestic dump trucks began back in the 1930s during the large-scale industrialization of the Soviet Union. At that time, the country lacked specialized construction machinery. Only a few prototypes of dump trucks existed, and even those were imported from abroad.

The first domestic models were built with very primitive designs. In fact, they were not true dump trucks, but regular flatbed trucks with a strong wooden sheet laid on the bed floor and then loaded with cargo. How was unloading done? Quite simply: the edge of the wooden sheet was lifted with a crane using special loops, and the load would slide off through the side, which had to be opened beforehand. Thus, the term “dump truck” was somewhat premature for such machines, as they did not truly unload themselves.

A more advanced version was later proposed by two Russian inventors. The body was more sophisticated, increasing labor efficiency. The principle was as follows: the sides were higher and could fold down. Two angled panels were installed at the bottom of the body. When the side panels were opened, the cargo slid off both sides under gravity. In this case, the term "dump truck" was more appropriate. These models were mainly used as road construction equipment.

Over time, Soviet engineers were tasked with designing a dump truck for widespread use at construction sites. As a result of collective efforts, a new dump truck was introduced and mass-produced: the YAS-1, developed at the Yaroslavl plant. It was based on the YAG-4 truck. The key innovation was the use of a hydraulic system to lift the metal-clad wooden body for unloading. Between 1934 and 1936, approximately 550–580 YAS-1 units were delivered to Soviet construction sites.

Soon other factories adopted the hydraulic system, leading to models like the ZIS-19 and GAZ-410. Despite the convenience of hydraulics, the cost was high. Therefore, during industrialization, some trucks still used manual lifting mechanisms with gears and levers. Though less practical, these were more economical to produce.

There were also dump trucks using an inertial unloading method, which required drivers to reverse quickly and stop abruptly. Due to the special design, the bed would continue moving forward and tip over, unloading the cargo before returning to its original position. These models were also used mainly in road construction.

Many homemade designs existed, but hydraulic systems gained the widest popularity due to their efficiency and reduced physical labor. Even today, hydraulics dominate dump truck designs. Modern construction vehicles use telescopic hydraulic cylinders with stroke lengths often exceeding the cylinder body. These rods extend in stages under oil pressure. Today’s market offers a wide range of such cylinders with parameters like stroke length (40–900 cm), number of stages (2–10), load capacity (from 1.4 tons), operating pressure (up to 32 MPa), and extension speed (up to 50 cm/s).