The lower drawing is of a PTO system where the implements input driveline connects directly to the tractor PTO stub. The following parts of the PTO have been found to be hazardous. The tractor's stub shaft, often called the PTO, transfers power from the tractor to the PTO-driven machine or implement. Power transfer is accomplished by connecting a drive shaft from the machinery to the tractor's PTO stub shaft. At all speeds, they rotate in proportion to the speed of the tractor engine.
Most incidents involving PTO stubs stem from clothing caught by an engaged but unguarded PTO stub.
Boot laces, pant legs, overalls and coveralls, sweat shirts, and windbreakers are clothing items that can be ome caught and wrapped around a spinning PTO stub shaft. The entire IID shaft is a wrapping point hazard if the IID is completely unshielded. Protruding pins and bolts used as connection locking devices are particularly adept at snagging clothing. If clothing doesn't tear or rip away, as it sometimes does for the fortunate, a persons limb or body may begin to wrap with the clothing. Even when wrapping doesn't occur, the affected part may become compressed so tightly by the clothing and shaft that the person is trapped against the shaft.