(Wrap Point. Source: University of Minnesota)
Any type of exposed rotating machine component can pose a wrap point or entanglement point hazard. Almost all field and stationary machines on a farm or ranch have one or more rotating parts, many of which present wrap point hazards. Examples of wrap points include power take-off (PTO) and secondary shafts on any machine, post-hole diggers, augers, and tines or blades on manure spreaders.
One of the most common wrap point hazards is the PTO unit, which rotates at a speed of at least 540 rpm, or nine rotations per second, when operating at full recommended speed. If a piece of a person's clothing or a shoelace is caught in a PTO rotating at this speed, the person could be entangled around the shaft in less than a second. A smooth shaft can be an entanglement hazard because force from the rotating shaft may be adequate to hold clothes against the shaft. Because clothing is more likely to catch on an uneven surface, the hazard increases when the shaft is not round; when there is dirt or debris such as mud, rust, or manure on the shaft (as shown in the image above); or when the shaft is nicked. Clothing can also become snagged on universal joints, keys, and fastening devices.
Wrap point incidents can result in the following injuries:
Incidents can result in fatalities if injuries are sufficiently severe.
You can reduce the risk of a wrap point incident by taking the actions that follow:
Click here to view a video about wrap point hazards from Pennsylvania State University’s Agricultural Safety and Health Program.
Click here to use the Farm/Agriculture/Rural Management-Hazard Analysis Tool (FARM-HAT) to determine the protection level of your machine master shield, PTO drivelines, and PTO warning decals.
Mechanical hazards: Wrap point. (2012). Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/66373/mechanical-hazards:-wrap-points.
Agricultural equipment and machine hazards. (2016). The Ohio State University. Retrieved from http://agsafety.osu.edu/programs/cfaes-osha/ag-equipment-machine-hazards.
American Society of Agricultural and Biological Engineers, 2009. ANSI/ASABE S604. Safety for power take-off (PTO), implement input drivelive (IID), implement input connection (IIC), and auxiliary power take-off (aux. PTO) for agricultural field equipment. St. Joseph, MI. Retrieved from https://elibrary.asabe.org/.
American Society of Agricultural and Biological Engineers, 2011. ANSI/ASABE AD500-1:2004. Agricultural tractors – Rear-mounted power take-off types 1,2 and 3 – Part 1: General specifications, safety requirements, dimensions for master shield and clearance zone. St. Joseph, MI. Retrieved from https://elibrary.asabe.org/.
FARM-HAT. (2010). Pennsylvania State University, Department of Agricultural and Biological Engineering, Agricultural Safety and Health. Retrieved from http://extension.psu.edu/business/ag-safety/farmhat.
Harshman, W., Yoder, A., Hilton, J., & Murphy, D. (2011) Mechanical hazards. HOSTA Task Sheet 3.1. Pennsylvania State University Agricultural and Biological Engineering Department. Retrieved from http://extension.psu.edu/business/ag-safety/youth-safety/national-safe-t....
Safety note #11: Power take-off safety. (2004) University of California, Agriculture and Natural Resources, Environmental Health and Safety. Retrieved from http://safety.ucanr.org/files/1364.pdf.