Patent ID: 8490585

Claim:
A work apparatus comprising: an air cooled combustion engine; a cooling air blower having a fan wheel and a cooling air spiral having a base; said cooling air blower being configured to generate a cooling air flow in a flow direction; an air output window having a pass-through cross-section arranged in said base of said cooling air spiral; a combustion air channel branching of from said air output window and leading from said cooling air blower to said combustion engine for conducting combustion air to said combustion engine in a flow direction; a guide wall projecting into said cooling air spiral and extending between said fan wheel and said air output window; and, said pass-through cross-section of said air output window tapering in said flow direction of said combustion air from a first pass-through area to a second pass-through area; wherein said guide wall has a roof section that overlaps said air output window at a distance (a); and, wherein said air output window has a radial back edge; said guide wall has a back end in said flow direction of said cooling air flow; said guide wail has a radial end section at said back end; said radial end section extends approximately along said radial back edge of said air output window; and, said radial end section forms an open pocket in which portions of the cooling air become trapped and thereby create a dynamic pressure above said air output window.