Abstract: In the embodiment of the invention described in the specification, a drive assembly for an eccentrically driven mass has a drive shaft which drives the mass by a first eccentric device and a secondary shaft, driven synchronously with the drive shaft, which drives a second eccentric device spaced from the first eccentric device so as to guide the mass in a constrained manner. The connection between the second eccentric device and the mass includes a resilient mounting. In order to avoid, or at least reduce, sinusoidally varying stresses imposed on the resilient mounting during operation as a result of deflection of the drive shaft, the eccentricity of the second eccentric device is larger than the eccentricity of the first eccentric device by at least a portion of the magnitude of the maximum deflection of the drive shaft in the region of the mass occurring during operation.