Abstract: Mechanism for vibrating frame-mounted screen panels having a housing containing integeared drive and driven shafts to which are keyed interfitting counterweights and which are journaled at opposite end portions in laterally spaced pairs of spherical roller bearings seated in correspondingly spaced pairs of cylindrical sockets in opposite sides of the housing, and an individual oil reservoir for each socket bounded inwardly by a crescent-shaped flange for maintaining oil therein at a level for wettig rollers of a bearing therein, the reservoirs being fed during operation of the mechanism by oil splashed by the rotating counterweights from a pool in a sump in the bottom of the housing.