Mechanical Hazards

Hazard	Mechanism	Typical location
Entanglement	Clothing, hair or gloves caught by a rotating part	Shafts, spindles, couplings, drills, augers
Drawing-in / trapping	Body part pulled into a nip	Meshing gears, rollers, belt and pulley, chain and sprocket, conveyor drums
Impact	Struck by a moving part	Robot arms, moving tables, reciprocating mechanisms
Crushing	Trapped between two parts or a part and a fixed object	Presses, platens, closing guards, moving carriages
Shearing	Trapped between a moving and a fixed edge	Guillotines, hydraulic rams, gates
Cutting / severing	Contact with a cutting edge	Saws, blades, knives, cutters
Stabbing / puncture	Contact with a sharp projection	Needles, swarf, tooling, ejected material
Ejection	Material or part thrown out	Grinders, lathes, injection moulding, wood machinery

In-running nips

The in-running nip — where two counter-rotating rollers meet, or a belt runs onto a pulley — is particularly dangerous because it draws the limb in at speed, and the reflex to pull away is far too slow. Serious hand and arm injuries from nips typically happen faster than a person can react, which is why the control must be a physical barrier rather than care.

Non-mechanical hazards

Machines also present electrical, thermal, noise, vibration, radiation, and substance hazards, and hydraulic or pneumatic pressure that can inject fluid through skin. A machine risk assessment covering only mechanical trapping is incomplete.