Abstract: A vehicle cab suspension unit has a support plate f or fixation to a vehicle frame, an impact plate for fixation to a cab of the vehicle, a pair of air springs supporting the impact plate above the support plate, and a pair of shock absorbers for damping changes in the separation between the impact and support plates. A track arm is pivotally connected between the support and impact plate s for permitting changes in the vertical separation of the plates and restraining lateral motion of the plates relative to one another. A U-shaped crash restraint strap is fixed to the support plate and loops over the track arm to restrain the track arm from excessive pivoting in an angular direction away from the support plate, so as to deform the suspension unit to absorb energy in a crash and resist complete separation of the support and impact plates.

Abstract: A vehicle cab suspension unit has a foundation which is secured to an outer rail of the frame of the vehicle and pivotally connects one end of a track arm. The other end of the track arm is supported above the foundation by an air spring, and a cab support yoke is pivotally connected between the ends of the track arm so as to support and secure the cab at a position along the track arm between its ends. Shock absorbers are provided between the foundation and the cab support yoke on both sides of the track arm. A height control valve maintains the height of the suspension unit and elastomeric snubbers on the foundation provide limits to the range of travel of the unit.