Description of the Hazard
Nip point hazards are present on nearly all rotating and reciprocating machinery. A nip point hazard is created whenever two adjacent parts of machinery move towards each other and have the potential to capture or draw-in foreign objects like body parts, loose clothing, or hair. This includes when both parts are moving (i.e. two meshing gears or infeed rollers) as well as when one part is stationary (i.e. a grinding wheel and a tool rest). These hazards are especially problematic because this type of motion tends to grab and pull an operator towards the hazard, thereby increase the severity of an incident.
Nip points are also known as “pinch points”, “in-running points”, and “draw-in points”.
Nip points are one of the leading causes of amputation and severe laceration. On larger machinery nip points can result in death.
Loose Articles and Clothing
Loose or hanging articles like clothes, lanyards, hair, and even appendages can easily become caught in a nip point. When this happens, the loose article can be wound-up in the machinery and pull anything attached to the article closer to the machinery, often leading to an increase in the severity of the injury.
The size and type of nip point can have a significant effect on the injury potential of a hazard. For example – if one part of the nip point is stationary (like the tool rest on a bench grinder), minimizing the gap can help to limit the severity of an injury.
The point of operation for some machinery is itself a nip point. Machinery like band saws, table saws, grinders, and lathes all require at least some kind of access to the point of operation and this leads to situations in which 100% isolation from a hazard is not possible.
Unexpected Hazards & Restarts
Nip points are not always obvious at a glance and this can lead to unexpected hazards being present during machine setup and maintenance activities.
Belts, Pulleys, and Shafts
Rotating parts, including the motor drive pulley, belting, pulleys, and shafts can cause significant injury if not properly guarded.
Example – OSHA Fatality Report
At 9:45 a.m. on February 2, 2019, an employee was polishing parts on a Doosan CNC lathe machine #2. The employee’s shirt/glove got caught on rotating piece. The employee was pulled into machine and struck on the head by the chuck. The employee sustained a skull fracture and was killed.OSHA ACCIDENT REPORT, INSPECTION: 1375843.015