Abstract: A torsional balancer device for a rotary shaft such as for a piston engine comprises a primary mass mounted upon the rotary shaft and a secondary mass resiliently supported and mounted with respect to the primary mass so as to be capable of resilient rotational movement with respect thereto. The primary and secondary masses have mutually facing surfaces which define a working space and a viscous damping agent is in the working space. The mutually facing surfaces have profiled configurations so as to form a plurality of chambers the widths of which are varied during relative vibration of the secondary mass with respect to the primary mass. The configurations may comprise coregistering ribs and grooves which have various cross-sectional shapes.

Abstract: A turret for a lathe has a substantially circular turret member pivotally mounted in front of the head stock and a plurality of support surfaces are formed on the periphery of the turret member. The support surfaces are each inclined with respect to the axis of rotation of the turret member and tool supports are pivotally mounted on the support surfaces.