The rotating shaft pulls you into and around the shaft in a fraction of a second. PTO shafts can quickly entangle and seriously injure even the strongest person. However, the rounder, smoother shafts are less likely to catch clothing than square shafts. The universals at the end of the PTO shafts are the most likely to catch loose clothing and cause a wrap-type injury. These bulky parts extend beyond the PTO shaft and can cause a wrap-type injury even if you are clear of the PTO shaft.
Shear points are areas where two pieces move in a cutting motion.
Shear injury can occur on a potato harvester at the boom joints, which can be raised and lowered. A finger placed in a boom joint or between a fan belt and the pulley would be quickly severed. The airhead engine, like any other engine, has moving parts which can be dangerous. The belt, turned by the engine which drives the fan, is a site for amputation as well as other bodily injuries. Crush points occur where two objects move towards each other or one object moves toward a stationary object.