Glossary · Guards and machine motion
In-running nip point
Also known as: ingoing nip point
In machine safety, an in-running nip point is a location where rotating surfaces move toward each other or where a rotating surface approaches a fixed surface, so that body parts, clothing or hair can be drawn in.
- Machine safety
- USA
In one sentence
In-running nip points form where rolls, belts or gears turn toward each other or a fixed part and draw in hands and clothing faster than people react.
Example
Where a conveyor belt runs onto its head pulley, the belt and pulley form an in-running nip point that is covered by a fixed guard.
How it applies
- Machine safety: OSHA's general machine guarding rule names ingoing nip points among the hazards that must be guarded. Typical locations are roll pairs, belts running onto pulleys, chains onto sprockets and meshing gears. The resulting harm is a drawing-in hazard.
- Design: Guard the nip itself, ideally with a fixed guard. Emergency stop devices do not replace guarding, because drawing-in happens too fast for a person to react.
- Human factors: Cleaning a running roll or belt is a classic cause of nip-point injuries. Instructions should require stopping and isolating the machine before cleaning.
- Technical documentation: Identify nip points in the risk assessment and mark them in maintenance drawings, so that service staff know where guards must be refitted.
In-running nip point vs. pinch point
A nip point involves at least one rotating part that draws material in. A pinch point can also arise between parts in linear motion.