Fifty years of drag chain innovation

June 2004 marked the 50th anniversary of Kabelschlepp, inventor of the drag chain or cable carrier, recalls Lorenz Klein, MD of Kabelschlepp Metool and grandson of founder Dr Oskar Waldrich.

June 2004 marked the 50th anniversary of Kabelschlepp, inventor of the drag chain or cable carrier.

The original development was registered in 1954 by the Waldrich machine tool company of Siegen, Germany.

It was one of a long series of innovations that propelled the company to the forefront of the German engineering industry under the dynamic leadership of Dr Oskar Waldrich (1880-1967).

The drag chain was originally developed for a machine tool, but Dr Waldrich saw at once how the principle could be applied to any industry where moving machinery is fed by power cables, pneumatic or hydraulic hose.

The name Kabelschlepp (cable drag in German) was adopted for the new device and also for the new company, founded a year after the patent was granted.

The first truly practicable chain was a mild-steel assembly, each link containing dozens of components.

Known as the 100 Series, it was sturdy and well engineered, if a little elaborate, but above all it was reliable.

The concept was brilliantly simple and so, like many revolutionary ideas, instantly understandable and persuasive.

The chain controlled and protected the cables or hoses when in movement, by limiting the radius of the travel and, because it did not sag, could form a free, self-supporting span.

Kabelschlepp's design was modular and so could easily be expanded into smaller and larger sizes.

As early as 1957, the first licence was granted, to Gleeson Reel of the USA, and this relationship led to the first significant redesign in 1963, when sharp edges were eliminated in favour of a fully enclosed stopping system and kidney-shaped holes.

The Mono-Series, the world's first plastic chain was introduced in 1967.

With its light weight, smooth running and high speed operation it proved a worldwide success, but the potential of plastic chains remained significantly underexploited until 1970 when a dedicated factory was built in Siegen.

When the original patent expired, competition entered the marketplace, bringing mass-produced copies of the Kabelschlepp chain into new industries, not previously targeted.

Kabelschlepp responded by developing a series of new, innovative designs to meet the rapidly changing demands of accelerating industrial technology.

In 1973, the frame stay was patented, eliminating the need for individually milled stays.

Conduflex was the world's first totally enclosed cable carrier incorporating stainless steel frames for protection against coolant and metal chips.

1983 saw the first modular plastic chain that could be opened on both the inner and outer sides.

The K-Series plastic chain was patented in the following year.

In the 1990s, the pace of innovation began to accelerate even further.

The M-Series, patented in 1990, was a chain with strengthened links for long-span applications that can be used open or closed.

Seven years later came the lightweight, versatile and long-lasting Uniflex.

1999 was the year of Quantum, a lightweight polypropylene extrusion rather than a chain made up of separate links, resulting in near-silent, vibration-free running with high-speed, long-life operation.

The construction is reinforced by an integral steel cable, making it virtually indestructible: tests have now exceeded 50 million cycles.

This was followed three years later by the revolutionary Robotrax, the first truly three-axis carrier, modelled on the human spine and designed specially for robotic applications.

On the whole, the trend has been towards more demanding and highly engineered applications and lighter, faster chains while maintaining reliability and long life.

However, through its Nottingham-based subsidiary Metool Products, Kabelschlepp also pioneered very large, stainless-steel drag chains for the first North Sea platforms, establishing a worldwide reputation in this exceptionally demanding field.

The company has recently supplied a platform in the Caspian Sea with what are believed to be the largest cable and hose drag chains ever built.

Innovation on this scale has required sustained and substantial investment, in human resources, process and technology.

Kabelschlepp invested in CAD as early as 1972 and, from the 1990s, has continued to refine KabelCad, a computer-based, expert carrier selection program, which enables interested parties to generate their own CAD images.

Two fundamental considerations support this philosophy.

First, all applications are more or less safety-critical, as they involve moving power cables and hoses, and so proven reliability is important.

Secondly, most moving machinery is relatively sophisticated and subject to more or less constant advances.

The answer is likely to be a broad package of solutions - not just plastic chains - but a full range of steel and hybrid products backed by proper engineering support and experience.

The trend towards package solutions is particularly marked in the automotive industry, were a supplier is expected to take an increased degree of responsibility for the specification of the cable as well as the carrier - and, of course, the performance of both.

The package philosophy led, in 1999, to the development of Life-Line, Kabelschlepp's own range of cables, specifically to meet the demand for higher speeds and greater frequency of movement.

Automotive also means true mass production, coupled with the highest quality and performance requirements.

Kabelschlepp has responded to the challenge, supplying millions of chain links with no quality issues or failures.

Kabelschlepp was also quick to face the challenge of low-cost manufacturing abroad.

First there were a number of very early licensing arrangements with companies in the old Eastern bloc and, more recently, a Chinese joint venture.

In 1990, the Slovak operation became a wholly owned subsidiary which now employs over 200 people.

For the future, micro-chains, first developed in the 1980s, will become an increasingly significant sector of the market with the growth in robotics and machines using fine power, electronic and pneumatic lines to operate grippers and robots.

Applications include advanced medical robotics, control cameras, laser cutting and welding equipment - all have to be 100% safe and dependable.

Kabelschlepp believes the market will continue to grow and new markets, such as the aerospace industry, will discover the benefits of increasingly sophisticated hose and cable carriers.

Here, the need can only be met by significant investment and engineering resource.

In the past, Kabelschlepp has doubled its output every ten years, by pioneering virtually all the significant developments in our field.

The company is committed to maintaining this level of innovation, investment and growth and is looking forward to the next 50 years.

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