DFK Cabs produces polycarbonate cabins
Good cabin design which ensures driver safety and comfort is an essential component of forklift design and manufacture. Melissa Barnett
looks at how this is achieved using a range of innovative cabin options and accessories available on the market.
The USA's National Institute of Occupational Safety and Health (NIOSH) has identified five main causes of the quarter million materials handling injuries each year: awkward lifting practices, repetitive movements, heavy lifting, stationary postures and extensive pressure point contact such as grasping or leaning against sharp edged surfaces. Exposure to heat and cold, loud noises and air pollutants contribute to driver fatigue, illness and accident.
NIOSH points out that although there are costs involved in improving working conditions, they can be offset by improved productivity. Consumer pressure and an increasing awareness of the benefits of a safe and ergonomic cabin have encouraged forklift manufacturers to incorporate a range of additional features into their cabin design.
Cabin layout can expose operators to excessive vibration, muscular injuries through the need to constantly turn the head to reverse or stretching to reach controls.
It has, for example, been estimated that a forklift driver can go through up to 2,000 arm and leg movements in one eight-hour shift, inevitably resulting in fatigue and injury.
In 2005, the German Federal Institute for Industrial Safety and Industrial Medicine calculated that every fourth day was lost to muscular-skeletal injury alone, with a net production loss of over EUR10.6 billion (USD15.4 billion) a year.
To avoid potential downtime through injury, the UK Government's health and safety executive suggests that employers should look at the following when assessing a work-space, such as a forklift cabin:
* Is the person in a comfortable position?
* Does the person experience discomfort, including aches, pain, fatigue or stress?
* Is the equipment appropriate, easy to use and well maintained?
Manufacturer Hyster believes that "both productivity and safety are enhanced when improved ergonomic design helps the operator". With this in mind, Hyster has included adjustable operator controls in its cabins which are arranged in close proximity to the driver and can be used by a wide range of operators.
German materials handling group KION, manufacturer of Linde and Still forklifts, states that all its devices and operating functions are constructed in line with the most recent technological and medical findings. To avoid wrist and arm strain, Still forklifts have incorporated fingertip hydraulic control operation and an armrest which can be adjusted to fit the length and height of the operator's arm and hand. German seat manufacturer Grammer goes one better with its Primo M seat by enabling the driver to also adjust the armrest by angle.
Raymond Corporation has fitted a three-tiered scalloped armrest and a multifunction control handle to its 4150 and 4250 series of stand-up counterbalance forklifts. A multifunction control means that operators can use minimal hand and arm movement to operate equipment.
Neck and shoulder
There have been a number of forklift cabin options designed to address the specific issue of driver neck and shoulder injury. From rotating cabins such as Jungheinrich's early experiments with the EFG D30, which utilised a 180 degree rotating cabin, to rotating seats now fitted to many forklifts. As well as reducing neck strain, rotating the seat or cabin minimises blind spots in the driver's peripheral vision.
In 1995, Toyota developed a revolutionary tilting cab for its BT Reflex series of warehouse forklifts which is still in production. Early research by Toyota found that forklift operators were 2.5 times more likely than other workers to suffer from neck injuries. BT's tilting cab allows the operator to see the fork tips when they are elevated, reducing neck bending by 10-15%; in a conventional reach truck, the driver must move his head in order to gain the same view.
Konecranes has elevating cabins
Reach stacker drivers, like their warehouse colleagues, are constantly required to look up to check their load. Konecranes recently delivered nine reach stackers to the Kuwait Port Authority with elevating cabins, allowing the driver to lift the cabin to five containers high, giving them the ability to view the second rail track.
An additional feature of the recently released Grammer Primo M seat is its backrest angle adjustment, which allows the driver to tilt the seat back by 30°, reducing neck strain from prolonged periods of extension. The seat also has an optional integrated backrest extension which can be adapted to suit the individual height of any driver.
US company Bahrns Materials Handling and Equipment has designed a simple but ergonomic solution to reduce neck and back strain from constant reversing. The Ergo back-up handle is a simple grip handle, attached to the inside of the overhead guard, keeping the driver's hand safely inside the cabin. It is designed to stop operators from grabbing the overhead guard during reversing, a dangerous practice that often results in hand injury. According to the designers, back strain is reduced because the handle also gives the driver something to hang on to when reversing. An optional horn button means that the driver can keep one hand on the steering wheel at all times.
Mirrors are still the simplest and cheapest way to reduce the repetitive head turning that forklift operators need to do when reversing and checking loads. Forklift mirrors are particularly useful in high pedestrian traffic environments, narrow internal aisles and at warehouse T-intersections.
Comatra's 4KLIFTCAM provides HD picture quality
Cabin-mounted cameras and monitors also greatly improve peripheral vision while reducing neck strain. A spokesman for industrial monitor supplier Comatra says that "Comatra's new 4KLIFTCAM is designed to reduce damaged goods, racks and pallets but also to reduce other related problems such as operator neck and back pain". The 4KLIFTCAM is mounted in four different locations on the forklift carriage, enabling the driver to choose his ideal viewing position. The camera uses high definition LED screen technology.
Driving over uneven surfaces and the subsequent ground vibration, referred to as low-frequency vibration, is one of the leading causes of lower back injury in forklift drivers. EU directive 2002/44/EC introduced minimum standards for workers exposed to risks arising from vibration. ISO 10326 defines the standards to which seat manufacturers must comply to minimise ground vibration. The forklift seat is the last stage of suspension before the driver.
Grammer's Primo M range of suspension seating has been specifically designed to reduce spinal injury. The seats come standard with intuitive weight adjustment, adjustable lumbar support, back rest and low profile mechanical suspension which reduces shock and vibration.
Raymond's 4150/4250 series of stand-up counterbalance forklifts incorporates ComfortStance suspension and a cushioned floor mat to protect drivers from vibration. ComfortStance works by automatically adjusting to each operator's weight.
Full suspension cabins on silent blocks and full suspension seating are standard on most new forklifts. Full suspension cabins are suspended on rubber buffers which absorb the forklift vibrations.
The most common cause of death in forklifts is roll-overs. Seat belts are designed to keep the forklift operator in the seat in case of a roll-over.
Although most new counterbalance forklifts come fitted with seat belts and it is mandatory in most countries to wear one if fitted, in reality they are seldom used, due to the constant driver entry and exits.
Due to an increase in insurance claims, however, most large companies try to enforce the regulations. A range of devices can now wire the seat belt so that the forklift fails to start unless the seat belt is in operation. Bahrns has designed the Safe-belt, 2009 winner of the Plant Engineering product of the year. The Safe-belt has a spring action which inhibits operator functionality if the belt is not engaged. It can be retro-fitted to most forklifts.
Dutch seat manufacturer EBLO has designed a personal protection system which is attached as guard rails to the cabin. The rails are lightweight and telescope back into the body of the truck when not in use, allowing for easy access to the cabin. The guard rails come in five bright, reflective colours which makes them easy to be seen from a distance and in dim light.
Mitsubishi's Grendia 1.5 to 5.5 tonne counterbalance forklift Hi-Vis roof recently won the Fork Lift Truck Association's 2011 award for safety. As the manufacturer explains, an overhead guard roof designed for protection from falling objects can actually hinder safety if it obscures the operator's vision. The Hi-Vis roof has no bars to hinder the view. Its combination of tough polycarbonate with a special coating resists scratching, weathering and deterioration with age which usually affects Perspex roofs.
CAT's cabin has PVC doors
Monica Escutia, spokesperson for Cat Lift Truck, says that the newly released DP/GP25-55N series offers a range of cabin options which improve safety and comfort - including sound-proofing, heating and defrosting, air-conditioning, audio system and a cabin mounted on four rubber shock mounts, resulting in very low noise and vibration levels.Cat has a range of fully built cabins available for retro-fitting. These cabins come in steel or PVC options. The PVC option offers all-round visibility, is water-proof and has mounted washers standard either forward or backward.
Czech company DFK Cab offers polycarbonate cabins which, CEO Dalibor Kaňovský explains, are lighter than traditional steel cabins, reducing tension on the blocks below the cabin. They are also transparent, increasing all-round visibility. The polycarbonate doors are virtually unbreakable, making them much safer than the traditional glass-windowed doors. Polycarbonate cabins are particularly useful in high lifting applications where a view of the load has to remain completely unobstructed.
Easy access to the cabin further reduces the risk of injury. Incorporating wide open or lower steps with slip-proof coatings into cabin design reduces the risk of slipping and injury. Hyster has designed their forklift steps to also be self-cleaning.
Hyster forklift operator consoles have a number of optional and standard safety devices fitted, including a parking brake warning alarm which reminds the driver to set the parking brake before leaving the cabin and a direction switch indicator which visually identifies for the driver the direction he has selected on the shift lever.
It should be obvious to both forklift manufacturers and end-users that a cabin design which provides safety and comfort will inevitably increase productivity and decrease down-time. As Toyota designers observe, "the benefits are clear: reduced demand on the operator, leading to greater speed and safety, significantly reducing the risk of accident and damage while boosting productivity".