Patent ID: 8590668

Claim:
A construction machine, comprising: a lower propelling body; an upper slewing body including an upper frame and slewably mounted on the lower propelling body; a cab including a floor plate and being installed on the upper frame; and a cab noise reduction device, the cab noise reduction device comprising: the floor plate; an under-cab member including a cab deck supporting the cab and being provided under the cab to define a closed-form under-cab space whose periphery is substantially closed, in cooperation with the floor plate; and a Helmholtz resonator provided in the under-cab space to reduce noise intruding into the under-cab space by a resonance effect, wherein the resonator includes: a hollow body portion having a sidewall; and an opening provided in the sidewall of the body portion and being uncovered when the cab is installed on the upper frame, to let an internal space of the body portion and the under-cab space outside the body portion communicate with each other through the opening.