Vibratory drive unit - has elastic device with non-linear resistance characteristic to radial weight displacement

摘要

A supporting component is fixed to a secondary shaft so that they cannot rotate in relation to each other, and has a weight mounted on it so as to give to the complete assembly a certain amount of imbalance, due to being eccentric to the axis of rotation. Thus the weight is displaced radially outwards and increases the degree of imbalance. An elastic device normally thrusts the weight towards the axis of rotation, and this has a non-linear resistance characteristic to the radial displacement. The elastic device can incorporate a first spring (3) offering resistance to radial displacement over a first speed range, and a second one (4) coming into action at the end of this range to provide additional resistance over a further range.