Lift axle suspension

In a lift axle suspension for a wheeled vehicle having a longitudinally extending frame member on either side of the vehicle, the suspension comprising with respect to each of said frame members, a substantially rigid, longitudinally extending beam, a hanger bracket means for attaching the beam to a longitudinal frame member, means for attaching and end of said beam to said bracket which retains said beam in a position substantially parallel to said longitudinal frame member and allows said beam to rotate about its attached end in a plane substantially parallel to said longitudinal frame member, said hanger bracket means including a substantially vertically extending plate member, an axle-to-beam connecting member spaced from said hanger bracket along said beam, a first expandable and retractable air bellows means functionally positioned between said beam and a respective frame member at a spaced distance from said hanger bracket means, and means for raising the axle so as to lift the wheels of the vehicle above a road surface and for lowering the axle, to lower the wheels of the vehicle onto the road surface, the improvement comprising as said means for raising and lowering the axle, a pivotal connection attached to said vertically extending plate member in such a manner that the longitudinal axis of said pivotal connection is positioned substantially parallel to the longitudinal direction of said frame member, a second expandable and retractable air bellows located between a pair of plate means, one of said plate means being rigidly attached in said suspension and the other of said plate means being attached to said pivotal connection in such a manner that said plate lies in a plane which is parallel to and rotates about the longitudinal axis of said pivotal connection, a link member connected at one end to said pivotally attached plate means and at the other end to said beam such that upon expansion or retraction of said second air bellows and the opposite movement of said first air bellows, said pivotally connected plate means and link member move with respect to said rigidly attached plate means thereby causing said beam to pivot at its connection with said hanger bracket and raise or lower the axle with respect to the road surface.