Workplace Health and Safety Queensland issued a safety alert that dealt with truck and trailer powered ramps and how to use them safely.
The safety alert was prompted by an incident where a worker was injured while he was assisting with the lowering of a ramp on a trailer that was being used to move a heavy mobile plant.
The ramp when it was raised was help in place on the trailer deck with a chain and chain-tensioning device (over-centre ‘dog’).
The worker was injured when he was helping a colleague to release the dog. He was standing at the back of the ramp on the left hand side and then pushed it forwards toward the front of the trailer.
As the dog released the ramp traveled backwards instead of forwards, dropping quickly and hitting him causing serious injury.
The full safety alert can be found at http://www.deir.qld.gov.au, we have included an excerpt below:
The worker was pushing against the ramp to reduce tension in the chain and assist in the removal of the over-centre dog (chain tensioning device).
These devices can release violently and cause injury to the operator, particularly if the chain has been over tensioned. In this case, the worker was struck by the falling ramp before he could move out of the way. The sudden release of the tensioned dog caused the ramp to spring back quickly then drop at a much faster rate than expected. If the chain had been tensioned with a device that could have been released from the side of the trailer, the worker would not have been in the way of the dropping ramp.
Workers should never stand where they could be struck by a falling ramp.
Ramps should not be secured for travel with over-centre dogs Load tensioning devices that have either ratchet or turnbuckle tensioning systems are better. Fixed length and specifically designed tie bars can also be used.
Clearly visible signs at the rear of the vehicle warning people to remain clear of ramps at all times help to highlight the risk.
If the lowering speed of the ramps is adjustable, the device used to vary the speed (e.g. a flow control valve) should be locked with a key or tool to minimise the likelihood of unauthorised use.
Only load rated chains, tensioners, connectors and anchors should be used to secure the ramps.
Ramps powered by double acting hydraulic cylinders (see photograph 4) are preferable to those powered by single acting cylinders. These ramps can be fully raised and lowered without the need for workers to touch the ramps. Single acting cylinder ramps require the operator to initially push the ramp to start it lowering.
This increases the risk of workers getting in the path of the ramps. These ramps also introduce exposure to hazardous manual tasks.
The likelihood of injury from single acting cylinder ramps can increase because an operator working alone will need to push the ramp with one hand while the other is operating the ramp control switch.
The ramp control switch should be of a type requiring constant pressure (also known as ‘deadman’), that requires the operator to stay next to the control panel during raising and lowering of the ramp, reducing the risk of the operator being in the path of the ramps.
The ramp control switch should be located on the left side of the trailer or vehicle where the operator is out of the path of the ramps and other vehicles.