Vehicle cab with dissimilar sound absorbing material

Claim 1

A sound absorbing means on a tractor comprising, a platform and a control console defining an operator station, a vehicle chassis, compartment means defining an engine compartment with said compartment means connected to said chassis, resilient means resiliently supporting said platform and control console on said chassis for arresting structural sound transmission from the engine compartment to said operator station, resilient means connecting said compartment means defining said engine compartment to said control console, said control console including a fire wAll adjacent said engine compartment, a rearward wall, upper and lower walls, and side walls defining a sound absorbing chamber between said engine compartment and said operator station, blocks of substantial volume of sound absorbing material for absorbing a range of high frequencies and blocks of substantial volume of sound absorbing material for absorbing a range of low frequencies extending into said sound absorbing chamber for absorbing airborne sound over a substantial range of frequencies that is transmitted from said engine compartment into said sound absorbing chamber toward said operator station, said rearward wall including a rearwardly and upwardly inclined portion joining an instrument panel extending upwardly intermediate said upper and lower walls reflecting sound for absorption into said sound absorbing material, said walls reverberating sound for absorption into said sound absorbing material, means supporting said sound absorbing materials on said walls in said sound absorbing chamber of said control console to thereby attenuate sound transmission from the engine compartment to the operator station.