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

Linear motion

Also known as: transverse motion

In machine safety, linear motion is movement along a straight path that can create crushing, shearing or impact hazards, for example where a moving part approaches a fixed part or a person.

  • Machine safety
  • Risk assessment

In one sentence

Linear motion of slides, rams, axes and carriages creates crushing, shearing and impact hazards wherever the moving part approaches something fixed.

Example

The gantry axis of a palletizer travels along a straight rail and creates a crushing hazard between the carriage and the end stop.

How it applies

  • Risk assessment: For every linear axis, identify where the moving part closes a gap with a fixed part, another moving part or a wall. These gaps are the crushing hazard and shearing hazard locations.
  • Machine safety: Measures include guards, minimum gaps that avoid crushing of body parts, and speed or force limits. In setup modes, Safely-Limited Speed (SLS) can reduce the hazard while a person is near the axis.
  • Technical documentation: Travel ranges and end positions belong in the machine description. Maintenance instructions should say how to secure vertical axes against falling under gravity when drives are de-energized.
  • Terminology: OSHA training material speaks of “transverse motion” for straight-line movement. Use one term consistently in a document set.

Linear motion vs. reciprocating motion

Linear motion is any straight-line movement. Reciprocating motion is the special case of repeated back-and-forth linear movement.

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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