Roll cages and wheeled racks - Manual handling
Manually propelled roll cages (basically a cage mounted on wheels) are used to transport goods within the factory, warehouse or retail store. Roll cages come in various forms but basically comprise a cage mounted on four wheels. Roll cages are supplied in a variety of heights ranging from 1550 mm up to 1830 mm (most operators cannot see over 1400 mm). Fully loaded roll cages may weigh 500 kg or more. Two common wheel sizes are 100 mm and 125 mm diameter.
The movement and loading of these pieces of equipment results in many injuries, mainly related to manual handling. Comprehensive industry data is not availalable but some companies that use roll cages continuously have found up to a third of their accidents are roll cage related. Injuries result from pushing/pulling especially up slopes, trying to prevent roll cages overbalancing (and crush injuries where this was not successful), repetitive loading and unloading, trapping hands and feet and roll cages falling off lorries (eg from a tail lift) during loading/unloading.
Roll cage design and construction is important. The frame should be robust and rigid with shelf arrangements that will withstand long-term use. Larger diameter wheels reduce pushing/pulling forces (eg the force required to overcome a small step are typically 20% greater if using a 100 mm wheel as opposed to a 125 mm wheel). Castors fitted close to corners improve stability. Handles should be incorporated at a height of approximately 1000 mm to move fingers away from corners of cages.
Castors and wheels
Robust wheel castors (eg stainless steel) with good quality wheel bearings are important. Ensure wheels and bearings are suitable for any harsh environment, such as high or low temperatures (eg ovens, freezers) or pressure washing. Wheel material should be carefully selected - hard materials such as nylon will lower rolling resistance, polyurethane wheels are quieter on rough surfaces and high-temperature rubber wheels are often a good option and are quiet in operation. Castors and wheels should be subject to routine maintenance, along with the roll cage generally.
Safe working advice
- only move one cage at a time
- move the cage no faster than walking speed
- wherever possible push the cage as this is ergonomically better than pulling it
- seek help on ramps and uneven surfaces
- stack heavier items at the bottom to lower the centre of gravity
- do not load above the load line or above the level where the operator can see over the load.