Operators sometimes remove or open interlocked guards or enter a danger zone to carry out adjustments/process correction. Where dangerous parts are unprotected, then the machine should only start by hold-to-run devices combined with:
- True inch – a single depression of the control button causes a maximum cylinder movement of 25 mm. (repeatedly pressing the button should not cause uninterrupted movement of the cylinders)
- Slow crawl– continued depression of the control button allows uninterrupted movement of the cylinders at a maximum of 1m/minute.
If these hold-to-run controls reduce the ability of the machine to perform its function, provided there is no substantial increased risk, the following can be used:
- Limited inch– a single depression of the control button causes a maximum cylinder movement of 75 mm. (again, it should not be possible to cause uninterrupted movement of the cylinders by repeatedly pressing the button);
- Fast slow crawl– continued depression of the control button allows uninterrupted movement of the cylinders at a maximum of 5m/minute.
If dangerous parts are protected by trip or nip bars when interlocked guards are opened/removed or persons enter a danger zone to carry out adjustments/process correction, continuous operation may be possible provided there is no substantial increased risk.
- Continuous slow crawl– uninterrupted movement of the cylinders at 1m/min (5m/min for web-fed machines) which does not require continued depression of the control button. Crawl speed may be increased to a maximum of 5m/min (10m/min for web-fed machines) only if there is no substantial increase in hazard.