Entanglement Hazards and Guarding for Mixers, Dough Sheeters, and Rollers

Where the Greatest Dangers Are

Many machinery injuries in food plants happen where "something rotating" meets "a hand." Common danger points:

• Between two counter-rotating rollers: On dough sheeters and laminators, once a finger or sleeve is caught, it gets drawn inward.
• Between a roller and a fixed part: The gaps between a conveyor belt and drum, or between a scraper and roller.
• Between the mixing arm and the bowl: Mixing arms for dough and fillings are most dangerous when a hand reaches into the bowl to scrape or remove material.
• Drive components: Belts and pulleys, chains and sprockets, gears, and exposed shafts.
• Screw feeders: The screw at the bottom of a hopper can catch a hand pushing material down.

These hazards are fast and powerful, and human reactions can't keep up. Long hair, wide cuffs, gloves, and apron strings can all be caught.

A Case From Hong Kong

A work safety alert issued in 2023 by the Occupational Safety and Health Branch of Hong Kong's Labour Department described how a female worker at a food factory fell into the mixing bowl while operating an electric mixer and was crushed to death by the rotating mixer arm. The Labour Department's recommendations to employers included: having a competent person carry out a risk assessment, fitting effective guards on all dangerous parts or enclosing danger zones with barriers, restricting entry by unauthorized persons; and when guards must be removed for inspection, repair, or cleaning, implementing a permit-to-work system and switching off and locking the power before entering the danger zone.

This isn't Taiwanese law, but it shows very concretely where the risks of mixers lie.

Taiwan's Regulatory Requirements

Chapter 3, "Prevention of Machinery Accidents," of the Occupational Safety and Health Facilities Regulations (職業安全衛生設施規則; the current text found at the time of writing was last amended on June 30, 2026) is the main basis:

• Article 43: Parts of machinery that could harm workers, such as prime movers, shafts, gears, pulleys, flywheels, drive wheels, and drive belts, must have guards, enclosures, sleeves, crossover bridges, or similar equipment.
• Article 44: Each machine must have its own power cutoff device such as a switch or clutch; on cutting, compressing, and other processing machines, the power cutoff must be located where workers can operate it without leaving their workstation; and contact or vibration must not cause the machine to start suddenly.
• Article 45: Power-driven machinery with significant hazards must have a clearly marked emergency brake device in an appropriate location that immediately cuts power and is linked to the braking system.
• Articles 49 and 50: Drive belts and shafts within 2 meters of the floor, or where people working or passing nearby could come into contact with them, must have railings, guard nets, or sleeves.
• Article 58: Drum-type machinery with nip point hazards, and hazardous parts of CNC or other automated machinery, must have guards, enclosures, or interlocked safety doors where the work could be hazardous.
• Article 76: Openings of crushers and mixers must have covers, enclosures, or railings at least 90 cm high to prevent falls; contact hazards between openings and moving parts must be guarded with enclosures or similar equipment.
• Article 77: When removing contents from a crusher or mixer, unless there is an automatic discharge mechanism, workers must be required to stop the machine before doing so.
• Article 78: Rolling machines with nip points must have enclosures, guide rollers, or interlocked safety guarding devices where there is a hazard.
• Article 57: During cleaning, oiling, inspection, repair, or adjustment, the machine must be stopped and locked out or tagged; see lockout rules.

Guards and Emergency Stops in Practice

• Fixed guards: Used on drive components that don't need to be opened often; ideally they can only be removed with tools.
• Interlocked covers: Where frequent opening is needed (such as feed openings and mixing bowl covers), opening stops the machine and it can only be started when closed.
• Emergency stop buttons: Red mushroom head on a yellow background, placed within the operator's reach and where bystanders can also press it; after being pressed, it must be manually reset before restarting.
• Feeding tools: When material must be pushed during operation, use pushers, scrapers, or other tools of sufficient length, not hands.
• Personnel: Don't wear gloves near rollers (Article 56 of the Facilities Regulations also requires telling workers not to use gloves for work with rotating cutting tools where contact is possible), tie up long hair, and fasten cuffs.
• Daily check: Before starting work, confirm that covers, interlock switches, and emergency stops are working; Article 327 of the Facilities Regulations prohibits workers from removing safety equipment or disabling it at will.

For detailed device explanations, see Emergency Stops, Safety Interlocks, and Guards.

FAQ

Q: Where are mixers and dough sheeters most dangerous?
A: Between counter-rotating rollers, between rollers and fixed parts, between the mixing arm and bowl wall, at exposed drive components, and at the screw feeder at the bottom of the hopper.

Q: Do the regulations require guards?
A: Yes. Article 43 of the Occupational Safety and Health Facilities Regulations requires guards and enclosures on drive components; Article 58 requires guards or interlocked safety doors on machinery with nip point hazards; Article 78 requires enclosures or interlocked guarding devices on rolling machines with nip points.

Q: Must machines have an emergency stop?
A: Article 45 of the Facilities Regulations requires power-driven machinery with significant hazards to have a clearly marked emergency brake device in an appropriate location.

Q: Can I reach in to remove material while the mixer is running?
A: No. Article 77 of the Facilities Regulations requires the machine to be stopped before removing contents from a mixer, unless there is an automatic discharge device.