Vehicular and/or walk behind vibratory compactors utilize a vibrated roller or plate to impose compaction forces on a densifiable strata, such as ground soil, a roadway base material or pavement. Utilizing a rotating energy source, such as a engine or hydraulic motor, to create the vibration appears...http://www.google.co.uk/patents/US6742960?utm_source=gb-gplus-sharePatent US6742960 - Vibratory compactor and method of using same
