Patent ID: 7878448

Claim:
An aircraft auxiliary power unit suspension system for isolating an aircraft auxiliary power unit having at least one aircraft auxiliary power unit operation frequency, said aircraft auxiliary power unit suspension system comprised of at least one longitudinal suspension linkage having a longitudinal length and a longitudinal length spring line of action running along said longitudinal length, said longitudinal suspension linkage terminating with a first elastomeric rod end, wherein said first elastomeric rod end has an elastomeric rod end intermediate elastomer with an elastomeric rod end intermediate elastomer radial thickness between an elastomeric rod end inner rigid member and an elastomeric rod end outer rigid member, said elastomeric rod end intermediate elastomer radial thickness at least 2mm, said elastomeric rod end inner rigid member having a center bore axis with said elastomeric rod end inner rigid member received inside said elastomeric rod end outer rigid member with said elastomeric rod end inner rigid member center bore axis nonparallel with said longitudinal length spring line of action with said first elastomeric rod end having an elastomeric rod end radial spring rate in the range from 20,000 to 100,000 lbs./inch , said elastomeric rod end intermediate elastomer radial thickness and said elastomeric rod end radial spring rate in the range from 20,000 to 100,000 lbs./inch aligned with said longitudinal length spring line of action wherein said aircraft auxiliary power unit suspension system provides said aircraft auxiliary power unit with a suspended auxiliary power unit natural frequency, said suspended auxiliary power unit natural frequency below said aircraft auxiliary power unit operation frequency.