Abstract: An improvement over U.S. Pat. No. 3,440,899 by McGavern. That patent includes a first plurality of shear liquid filled cavities defined by through apertures in the elastomer member. The improvement of this invention resides in adding a second plurality of shear liquid filled cavities, the cavities located in the inertia member at a surface thereof interfaced with the elastomer member. By this construction the total volume of shear liquid is increased, thereby increasing the damping action of the torsional vibration damper.

Abstract: A constant-tension spring device for the accessory belt of an automobile engine. The device includes a cylinder having an elastomer ring mounted within each of its ends. A rod passes through each elastomer ring, the rod having spaced shoulders each bearing against one end of a respective elastomer ring. Abutments within the cylinder position and retain the elastomer rings. Upon sufficient axial motion between the rod and cylinder, the elastomer rings are distorted by twisting and display a flat segment of the load vs. deflection curve between the rod and cylinder. The spring device maintains a desired tension within the accessory belt, compensating for temperature, humidity, and ageing changes in belt length which would otherwise result in change of belt tension.