Air spring unit for suspension systems

Claim 1

In combination with a suspension system for a vehicle of a type including a load-supporting axle and a leaf-spring assembly extended transversely of said axle and mounted thereon in a loadsupporting relation with the frame of the vehicle, an improved air spring unit comprising: A. means including a bracket suspended from said frame; B. a force dissipating arm of an elongated configuration; C. coupling means supporting said arm for pivotal motion in a vertical plane, including a horizontally extended pivot pin for pivotally connecting one end of said arm to said bracket in a coplanar relationship therewith; D. a variably pressurized air bag interposed between said arm and said bracket and connected with said arm at the end thereof opposite said one end; E. means for maintaining the height dimension of said air bag substantially constant, including an operable leveling valve connected with said air bag for varying the pressure within the air bag as predetermined pivotal motion in opposite directions is imparted to the force dissipating arm, and motion limiting means including a motion limiting stop for arresting pivotal motion of said force dissipating arm in at least one direction; and F. means for causing the air bag to support said arm in a substantially uniform manner against rotation about said pivot pin through a moment arm of a substantially fixed length including a wear plate defined on said arm in juxtaposition with said one end of the arm and in spaced relation with the end thereof opposite said one end, said wear plate being continuously seated on said leaf-spring assembly with the juxtaposed surfaces of the wear plate and the leaf-spring assembly being mated in a slidable relationship.