Tag axle assembly

Abstract

A tag axle assembly has a frame having a pair of hanger brackets, an upper cross tube and a lower cross tube. A pair of rocker beams having a primary pivot for pivotally mounting the rocker beam to the support frame is mounted to the frame. A suspension air spring extends between the upper cross tube and each rocker beam, and a lift air spring extends between each hanger bracket and the front end of the rocker beam. An axle seat is hingedly mounted to the rear end of each rocker beam. An upper beam having an actuator beam and a lift bar are pivotally mounted to the axle seat and to the support frame. A linear actuator extends between the support frame and the actuator beam. Inflation of the lift air spring causes the rocker beams to rotate about the primary pivots, and expansion of the linear actuator causes the actuator beam and the interconnected lift bar to raise. As the interconnected lift bar raises, it applies an upward force to the axle seats such that the axle seats rotate about the hinge pins relative to the rocker beams. Such rotation causes the axle seats to raise further out of the ground engaging position and forward. To move the suspension into ground engaging position, the lift air springs are collapsed, and the effective length of the linear actuator is reduced while simultaneously, the suspension air springs are inflated to carry load.