Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Guards and machine motion

Rotary motion

Also known as: rotating motion

In machine safety, rotary motion is continuous motion around an axis that can create entanglement, drawing-in, cutting or impact hazards, even at low speed and on smooth surfaces.

  • Machine safety
  • Risk assessment

In one sentence

Rotary motion of shafts, spindles, rolls and blades can entangle hair and clothing or draw in hands, even when the part turns slowly and looks smooth.

Example

A slowly turning shaft end protruding from a mixer gearbox catches a loose sleeve; a fixed cover over the shaft end prevents this entanglement hazard.

How it applies

  • Risk assessment: Rotating parts cause entanglement hazards through projections, keyways and set screws, and drawing-in hazards where they form nip points. Blades and cutters add cutting hazards.
  • Machine safety: Rotating parts can keep turning after a stop command. Check the stopping time and use guard locking where run-down outlasts the time needed to reach the part.
  • Human factors: Slow rotation looks harmless and invites people to touch or clean running parts. Warnings and instructions should explicitly forbid this.
  • Technical documentation: Name rotating parts in the operating manual, state required clothing rules (no loose clothing, tied-back hair) and describe how to confirm standstill before access.

Rotary motion vs. oscillating motion

Rotary motion continues in one direction around an axis. Oscillating motion reverses within a limited angle.

By knowledge.aitechdoc.world · Published September 25, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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