Exploring the Likelihood of Entanglements and Interactions with a PTO Knuckle

Abstract. Power take-off (PTO) is a common method of transferring power from a tractor to a towed piece of machinery. The PTO is also a well-documented cause of severe and often permanent disabling injuries to farm operators. The physical conditions that cause entanglements are not well established. Several studies have explored the parameters of PTO entanglements as materials have been drawn across a rotating PTO knuckle to test for entanglement probability. The objective of this study was to determine probability of entanglement when materials are dropped vertically onto a PTO knuckle spinning at 540 RPM. A total of 360 randomized trials were conducted with 10 replications for each of the six positions (center of yoke, edge of yoke rotating downward, edge of yoke rotating upward, center of cross, edge of cross rotating downward, and edge of cross rotating upward), and six different types of materials (woven cotton athletic shoe lace, cotton work boot lace, leather boot lace, cotton twine, denim strip, and Tyvek® strip). Not a single entanglement was recorded. Dramatic high speed video imagery authenticates the material‘s motion and path as it interacts with the rotating PTO knuckle.