Giving key workers a mechanical lift

Few companies have a strategy for avoiding injury caused by handling heavy loads. But mechanical lifting aids are gaining favour and may be essential to keep up with the law.

It is now over eight years since legislation was introduced to protect from injury employees whose job it was to handle heavy loads. Yet the injuries continue.

A few companies approach ergonomics of the workplace seriously, introducing assist devices and lifting equipment to relieve operators of heavy and awkward handling tasks.

But according to Dr Ian Randle, a director of Northampton ergonomics consultancyHu-Tech Associates, most are negligent, and many are breaking the law.

The legislation relating to manual handling, The Manual Handling Operations Regulations 1992, details the weights that operators are permitted to handle while performing different lifting, stretching and twisting actions.

It is legislation that is good as far as it goes, says Randle. But he claims that ‘most firms are missing opportunities to get ergonomics as good as it could be, and many are not complying with the letter of the law’.

Randle’s observations are largely based on litigation cases and civil actions he regularly encounters, where upper limb and back injuries have beensustained as a result of poorly-designed manufacturing processes. But he adds that there are exceptions. ‘A handful of innovative forward-thinking, usually world-class organisations, have an ergonomic strategy, and are seeking to build ergonomics into their manufacturing systems. It is a cost-effective approach in the long term,’ he says.

In the US it is normal for plants to have an ergonomics programme manager, but it is extremely unusual in the UK. One UK plant where ergonomics has played a major role in manufacturing process design is BMW’s newly-renovated Oxford plant, where the new Mini is being built. While it is common to use scissor lifts on automotive assembly lines to adjust the height of the car to provide optimum workingconditions, BMW has gone one stage further for the new Mini. In the area where operators work on the underside of the car, the body is grabbed by a rotary sling, supplied by Swisslog, and rotated through 90º so it can be worked on in comfort at waist height.

Another ergonomic feature at Cowley is the provision of assist-devices to help take the weight where operators are required to manipulate heavy loads. These are used to advantage in two areas: for handling sub-assemblies and heavy parts to facilitate assembly manoeuvres, and to reduce the impact of high-power screwing operations carried out by operators using electric tools.

Trim and final manager Robin Charlton says: ‘Any tool for carrying out a fixing that requires a torque value of more than 60Nm, for example on a drive shaft, needs to be equipped with an assistor. This is because, for such high torques, the gun has a big kickback like a shotgun. Instead of the operator taking the kickback, it all goes through the assistor.’

The operator simply moves the tool into position for the assembly job and initiates the fixation program by pushing a button, before removing the tool and positioning it for the next vehicle. Some 40-50 of the DC tools in use on the Mini trim and final assembly line are fitted with assistors.

Assistors are also necessary to improve the ergonomics of the assembly operations for the sunroof, exhaust system, cockpit and battery. ‘In the old days, two operators would move the petrol tanks around above their heads. Now they manipulate them with the aid of an assistor under the control of a hand-held pendant with up/down and forward/back buttons,’ says Charlton.

Specific applications

Two assistors are needed for the exhaust system – one for taking the module out of the delivery pallet, the other for positioning it under the vehicle while the operator screws it in place.

This particular assistor floats on an air cushion to position the exhaust under the vehicle.

One of the downsides of using manipulators is that they are tailored to specific applications. This means that all the assistors at Cowley would have to be replaced if a new model were introduced, says Charlton. ‘It is obviously an expensive burden, but we have to take account of the ergonomic factors and the effect on our operators.’

Jaguar is also using assist devices on a large scale at its Halewood plant which started building the X-Type earlier this year. A total of 56 manipulators from Italian specialist Dalmec are operating in the body and trim and final assembly shops. ‘They are not only used for helping manoeuvre heavy weights,’ says Jackie Leotardi, operations manager at Dalmec’s UK arm. ‘If you are carrying out a particular job on a prolonged basis within a confined space and operate at awkward heights, then you need an assistor there too.’

Easy manoeuvrability

The Dalmec assistor operates on a lever principle with compressed air providing the counterbalancing system rather than a weight. It enables operators to manoeuvre parts by guiding the manipulator without taking any of the weight. Typical examples are picking the sunroof from a stillage and putting it into the car’s roof, placing the spare wheel in the boot and moving the seats into the car.

Where particularly heavy weights are being handled, a scissor lift table is the only solution, for moving the load and moving the operators. Cummins Engine Company has introduced both approaches.

At its Daventry plant, where Cummins builds its most powerful range of diesel engines, scissor lift tables are widely employed to ensure that operators have easy access to the engines for risk-free assembly, inspection and adjustmentoperations. A total of 11 scissor lift tables supplied by Northampton-based Hymo are now in operation.

In one of Cummins’ installations two 1,2000kg capacity lift tables are sunk into specially-constructed floor pits. The engines are supported on 3,500mm x 1,500mm platforms on the lift table. Operators, using push-button control units, stand at floor level and raise or lower the engine as necessary to achieve a comfortable working position.

In another area at Cummins, the operator stands on a platform supported on a scissor lift table. The operator adjusts the height of the platform to ensure he can conduct his or her duties without bending, stretching or stooping.

The legislation does not cover the area of lightweight handling involving repetitive tasks over long periods of time. For such operations, the Health & Safety Executive offers guidance but employers are of course not bound to follow it. ‘Repetitive manual work on production lines is an at-risk area for injuries. There are packing and assembly operations that are being done the same way today as they have been done for decades,’ says Randle.

Dalmec’s Leotardi identifies the foundry industry as being negligent with regard to lifting devices. ‘Employers ignore the regulations a lot. They consider ergonomics a low priority until an accident occurs. Then they come screaming to us asking for the equipment tomorrow.’

Randle urges the importance of careful planning to ensure the correct assist devices are applied for the appropriate tasks. He says it is not infrequent to find that companies have made well-intentioned attempts to assist their operators by introducing manipulators and lifting equipment, only to find that they are not used.

‘If operators judge that the equipment is awkward to use and they can do the job quicker and more easily without it, then it will remain idle.’