What does forklift engineering heritage mean for you?

Directions of development in lift truck technology – past and present

Deep expertise, built upon a long and distinguished engineering heritage, reinforces customer confidence in a brand like Cat® Lift Trucks. In fact, this manufacturer’s historical connections stretch right back to forklift development’s earliest days. Ruari McCallion summarises the key steps in lift truck evolution and how they benefit customers today.

Forklift trucks: a century and a half of evolution

Goods-carrying wheeled vehicles are probably as old as the wheel itself and they proved to be as much as humanity needed, for thousands of years; but necessity is the mother of invention. The demands of production from the dawn of the Industrial Age, and the booming output from industries and agriculture in the 19th Century, gave birth to: initially, powered platforms; and then, just over 100 years ago, the first trucks that combined horizontal movement with powered lifting.

The dawn of powered forklift trucks

Towmotor Corporation, which became part of the Caterpillar organisation in 1965, was one of the two pioneering companies that introduced forklifting mechanisms to powered lifting trucks – and so the forklift truck was born.

They were still fairly crude, especially in their lifting mechanisms, and the lifting capacity was very low by modern standards – less than a tonne even on the biggest trucks. But they were more effective than their predecessors and, as a result, encouraged other companies to pick up the idea and run with it.

The 1920s saw rapid expansion of industry and agriculture across Europe and the Americas. Market demand led to forklift truck capacities increasing, quite quickly. By the end of the 1930s, machines could lift between 1.3 and 2.2 tonnes – or 3,000 to 5,000 lbs; the American companies that were leading the way worked to the imperial units they were comfortable with and so talked in round numbers of thousands of lbs when discussing weights and capacities.

Widening choices

It was the development of hydraulic lifting systems that made the rapid increase in capacity possible but motive power had a major role, too. Operators could, by the 1930s, choose from: gasoline (petrol) vehicles; the torquey and efficient diesel engines that were fast gaining market share; and from lead-acid battery power, on smaller-capacity trucks.

The core technology of a series of heavy, lead-acid batteries that had to be recharged at the end of every shift was to stay largely unchanged for nearly 90 years, until the emergence of practical lithium-ion (Li-ion) batteries at commercial scale. However, what they did, from day one, was allow forklift trucks to be used more freely and extensively in confined environments, such as warehouses, without suffocating everyone with exhaust fumes.

The great leap forward: war economy

Necessity, in the shape of World War 2, intervened once more to accelerate the development of ‘forklift troops trucks’. The global conflict created more than one impetus. Manpower was at a premium as most adult males were enrolled in their nations’ armed forces. At the same time, the need for rapid movement of materials – munitions, supplies and food, of course – became extremely pressing. Dock space was also at a premium. In theory, especially in America, docks could expand as far inland as required. In practice, stores needed to be kept close to loading/unloading areas. Travelling miles from store to ship, to truck convoys, etc., was a waste of vital time.

Warehouses and depots got taller and space for manoeuvring got tighter. High-reach, highly manoeuvrable vehicles became standard military logistics equipment. After the war they were readily adapted for civilian use, in warehousing, logistics and manufacturing.

The first narrow electric reach truck was launched in the UK in 1954. It enabled high-bay storage and expanded usable space. As a result, it helped to transform warehouse design.

Without the pressure from surging productivity, as in the 1920s, or war needs, we saw a steady evolution, rather than revolution, of forklift truck design from the 1950s onwards. Caterpillar became a strong player in the market when, in 1965, it acquired the Towmotor Corporation, one of the first, pioneering forklift truck manufacturers.

New power and shifting demand

Development has accelerated again in the late 20th and early 21st century, driven by a number of factors. Globalisation has seen an explosion in international trade and, with it, demand for logistics and associated warehouse space. More recently, Covid lockdowns encouraged people to buy from remote vendors like Amazon and Barnes & Noble, which supply from giant distribution centres. This has seen mushrooming demand for forklift truck fleets.

Further drivers of change have included: legislation on emissions control; greater emphasis on driver safety (such as safety cages and seatbelts) and comfort; and the emergence of practical alternatives to diesel power, such as LPG/propane internal combustion engines and more powerful electric power.

The arrival of practical Li-ion battery power has had profound effects on the design of electric forklift trucks. Lead-acid batteries are often heavy enough to act as counterweights on their own; Li-ion batteries last longer and can be recharged faster than lead-acid but they are much lighter. This means that designs don’t have to be restricted to the order forks-mast-driver-battery compartment, running front to back, and it means that capacity isn’t automatically tied to the weight of the batteries and their counterbalance effect. Designers can put weight wherever they wish, including closer to the vehicle floor; a lower centre of gravity improves stability.

Furthermore, as Li-ion batteries can be charged faster, it means that individual forklifts can be available for more hours in the day.

Weighty matters: from less than a tonne to AI and AGVs

The early days, when the most powerful forklift trucks could lift no more than 900 kg, are far behind us. Those weights are coming within the reach of body-worn exoskeletons. Standard trucks can lift 1.5 to 3.5 tonnes; heavy industrial forklifts can carry 50 tonnes; and specialised port machines can have capacities exceeding 70 tonnes.

So what does the future hold; regular readers of Eureka all know that we have been marking milestones and describing developments for over 15 years. We haven’t yet reached the stage of exoskeletons such as that worn by Ripley in the second of the Alien movies, when she used its power to defeat the Alien predator, but their capacities are increasing.

The power of electric vehicles is increasing apace. For a long time, single electric battery cells were capable of powering no more than 1.5 volts each, no matter how big they were. Lithium-ion batteries are already more than double that, or even triple; a fully charged cell can be rated at up to 4.7 volts. As Li-ion is more energy-dense than lead-acid, they are also lighter and smaller, so a forklift truck chassis can carry much more Li-ion power than the traditional lead-acid units. They have served us well for a century but the ‘old faithful’ may have seen its day.

Automated guided vehicles (AGVs) are becoming a quite common sight in warehouses across the world. The next logical development is for genuinely autonomous vehicles, which can make their own decisions and choose their own paths, based on the tasks assigned to them. Will we see warehouses that are so completely automated and controlled by artificial intelligence (AI) that there will be hardly anyone in the building except for maybe a bored supervisor in an elevated control office?

Probably not. If we have learned nothing else from the last 150 years, it is that automation rarely, if ever, delivers on its most extravagant promises! But it will always make a change and usually for the more profitable.

So, raise a glass to 100 years of the forklift truck, to a rich and fascinating history – and to what may be an even more exciting future.

Click here for further information on the heritage of Cat Lift Trucks.

Forklift truck evolution: a timeline