Glossary · Guards and machine motion
Power transmission apparatus
Also known as: mechanical power-transmission apparatus
In machine safety, power transmission apparatus are the machine components that transmit energy or motion, including shafts, belts, pulleys, gears, chains, sprockets and couplings, as distinct from the point of operation where work is done.
- Machine safety
- USA
In one sentence
Power transmission apparatus such as shafts, belts, pulleys, gears and couplings must be guarded, since people rarely need access to them during operation.
Example
The V-belt drive and coupling between the motor and the pump of a hydraulic press unit are enclosed by a fixed guard that is removed only during maintenance.
How it applies
- Machine safety: Transmission parts create entanglement hazards and in-running nip points. Because operators rarely need access, complete enclosure with a fixed guard is the usual measure.
- USA: OSHA covers mechanical power-transmission apparatus in 29 CFR 1910.219, in addition to the general machine guarding rule in 29 CFR 1910.212.
- Maintenance: Belt tensioning, lubrication and coupling alignment require guard removal. The maintenance manual should require energy isolation first and, where possible, allow lubrication from outside the guard.
- Technical documentation: List transmission guards as parts of the machine, with replacement part numbers, so that damaged guards are replaced rather than left off.