The invention discloses a compaction mechanism of a fast-assembling dolly of an engine, and belongs to the field of equipment for
vehicle detection. The compaction mechanism comprises a soleplate, four compaction assemblies are arranged on the soleplate, each compaction
assembly comprises a rotating wheel, a driving belt and a weight, and each rotating wheel is connected with a hydraulic rotatingoil cylinder; and the soleplate is provided with a weight stop mechanism which comprises a sliding body and a
ratchet hinged to the axial center of the weight, the sliding body comprises a spur rack and a
ratchet strip fixedly connected to the spur rack, the
ratchet strip is engaged with the ratchet, the spur rack is in sliding connection to the soleplate, the frame is in rotational connection with first and second rotating shafts, the rotating wheel sleeves the first rotating shaft, a first unidirectional bearing is arranged between the rotating wheel and the first rotating shaft, the gear sleeves the second rotating shaft, a second unidirectional bearing is arranged between the
gear wheel and the second rotating shaft, the spur rack is engaged with the gear, and a belt is wound around the first and second rotating shafts. Via the compaction mechanism, the magnitude of a clamp force can be adjusted freely.