Forestry machines come in all shapes and sizes. In many, the operator sits in a cab with windows that are usually made of polycarbonate, a heavy-duty plastic that provides protection from heat, air, dust, and noise.
Though the rotating cutting devices such as chainsaw and disk cutters that the machines use to cut have improved the efficiency of forest operations immensely, these improvements have also brought additional hazards to forest equipment operators.
Rotational energy coupled with cutting edges makes very efficient tools for cutting trees, masticating, chipping or grinding vegetation and debris, and even chewing up forest road surfaces. However, when something breaks, the flying object can be a real hazard. Chainsaw chain travels at about 150 feet per second; the cutting edge of a saw head can travel at twice that speed.
“Some high-tech forestry machines use chainsaw cutters to process trees into logs,” says Bob Rummer, project leader of the Southern Research Station (SRS) Forest Operations Research unit. “Severe injuries can occur if the chain breaks during cutting. Small broken pieces can go flying at very high speeds (a phenomenon called chainshot) and can penetrate cab windows.”
Improving protective structures for operators of forest machines continues to be a huge dilemma. Many forest machines have fully enclosed cabs to provide a comfortable work environment, but they’re not always constructed with materials that can deflect a flying sawhead or chainshot. Rummer and his staff in Auburn, AL, have conducted research and lab studies on improving the safety of these machines since 2008. Recent research examined how window thickness and material construction affect resistance to impact from thrown objects.
From The USFS Southern Research Station: https://www.srs.fs.usda.gov/compass/2012/04/17/better-protection-for-forest-machinery-operators/