Plaintiff, 22 years old, was injured in Dryden, Maine, while he was idling a snowmobile. The speed-governor bell separated from the drive shaft, crashed through the engine housing, and struck the plaintiff in the face.
Plaintiff sustained multiple fractures of the jaw and nose, but reached an end result without cosmetic deformity and with no major functional loss. Expert engineering analysis established that the speed-governor bell, a centrifugal clutch arrangement, was inadequately secured to the end of the drive shaft by a single bolt and a simple washer. During normal idling or backing up of the snowmobile the drive shaft and governor bell rotated in such a manner as to unscrew the bolt, causing the free-spinning governor bell to fly off the drive shaft. An action in negligent design was based on the defendant’s failure to key or lock the bolt arrangement to the shaft so that the governor bell could not rotate with on the drive shaft.