In vibratory plates (vibratory plate compactor machine), the reciprocating movement of an engine piston is converted into rotation of the crankshaft, and the latter is converted into rotation of an eccentric rotary shaft of vibrator unit, which create a periodic force that leads to reciprocating movement of the plate. Such a vibratory plate is complicated.

It is proposed to use a free-piston engine with one piston as the engine for a vibratory plate. In this free piston engine, the piston moves reciprocally, and the cylinder performs reciprocating movements opposite to the movements of the piston. The cylinder is mounted vertically and fixed to the plate. In each engine cycle the gas pressure acts on the piston and cylinder. After combustion, the piston moves up and the cylinder moves down. Since the cylinder is fixed to the plate, it also moves downward and compacts soil, gravel, etc.