Suspension for a truck tilt cab

Abstract

A tilt-cab truck with the cab independently suspended on the main frame. A power device for tilting is connected to the cab and the frame at pivots spaced away from the main cab pivot. On each side of the truck a front suspension bell crank is pivoted to the cab by a main pivot and has an arm extending substantially horizontally back to a pivotal connected to the main frame, with a crank arm extending down from the rear and bearing on one end of a horizontal front air spring that is secured to the main frame at its other end. A leveling valve assembly for maintaining cab height relative to the frame is connected to the front air springs and to a source of air pressure. An anti-roll structure is rigidly connected at each end to the bell crank and extends down below it and then laterally across to the other side of the truck. A pair of lower latch assemblies are each secured to the main frame near the rear of the cab, and a pair of upper latch assemblies are each releasably secured to a lower latch assembly. A pair of horizontal rear links are each pivotally connected at a forward end to the cab and at a rear end to an upper latch assembly, and a pair of rear air springs are each mounted on an upper latch assembly with an upper end bearing against the cab. A leveling valve assembly for each rear air spring is connected to the source of air pressure, for maintaining the cab height relative to the frame. A pair of front damper-snubbers, each adjacent to the main pivot, are operatively interposed between the cab and the main frame, and a pair of rear damper-snubbers, each adjacent to the rear end of one rear link, are interposed between the cab and the upper latch assembly, each damper-snubber has hydraulic cushioning for preventing bottoming out at each end of its stroke.