Ring structure for preventing blade damage

A centrifugal snow blower for clearing snow fall comprising a housing defining an opening in the direction of clearing, a fan rotatable about a central axis arranged within said housing, said fan comprising a rotatable shaft having a plurality of curved scoop-like blades, each of which has one end attached to said shaft, each of said blades extending radially from and axially of said shaft to protrude axially through said opening and at least in part out of said housing, said blades each terminating in a rounded leading or cutting edge with the forwardmost extent of each blade being located in a common plane outside said housing and perpendicular to the shaft, and means for preventing introduction of obstacles into said housing and damage to said blades comprising a ring concentric to the central axis of said fan welded to said rounded leading or cutting edges between their forwardmost extent and the front of said housing.