When you hear the word automation, everyone agrees: it requires processes that are as precise, reliable and fast as possible, processes that can be synchronised and work around the clock. Without exception. Cable chain systems are an indispensable part of process automation because there are applications in almost every production site which require machine parts to be continuously supplied with power, data or media, such as air and water. On this page, you will find out exactly what is meant by a cable chain, when it is used, which materials are available for cable chains, what arrangement and mounting options are available, and last but not least what you need to keep in mind when selecting the appropriate cable chain cables.
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What is a cable chain and what task does it perform?
A cable chain is a mechanical system that protects, supports and guides cables and media hoses in permanently moving machine applications.
The movements in the cable chain are performed in a controlled manner so that the forces permanently acting on the cable or the media hose do not cause premature damage or failure. Cables and media hoses are ultimately subjected to millions of bending movements along the travel distance in the cable chain.
What are the essential features of a cable chain?
It enables the electrical, optical, hydraulic or pneumatic connection between two points in linear movement in an easy and efficient way. Certain cable chains enable rotations of up to 540° and can therefore also perform three-dimensional movements, as required in robotics applications.
It guides and supports the cables and hoses contained within it in a controlled manner, while observing the minimum permissible bending radius.
It provides mechanical protection for cables and hoses and even separates them from chemical environmental influences if they are enclosed with protective covers.
This not only reduces the number of maintenance intervals for cables and hoses, but also increases their service life.
How is a drag chain constructed?
A cable chain is made up of many interconnected chain links that are closed on both short sides. The size of the chain link is determined by the number and dimensions of the cables.
A single chain link consists of the following elements:
- Side band
- Connecting pin: the individual sideband chain links are connected to each other with connecting pins.
- Frame stay (with or without protective covers) are available in a wide range of variants. In addition to open variants, there are also those with protective covers made of plastic, aluminium, steel or even stainless steel to protect the cables from environmental conditions if necessary.
- Separators on the other hand, ensure the correct positioning and separation of cables and hoses within the cable chain. They are attached vertically to the frame stay.
- Connecting elements are used for a variety of mounting positions so that the cable chain can be attached to the system or machine at both ends.
What advantages does a cable chain have compared to cable trolley systems?
Competitive advantages of the cable chains as compared to the traditional systems, like conductor bars and festoon suspensions and cable trolley systems are:
- they shine thanks to the ability to carry different kinds of utilities (power, signal and data cables as well as hydraulic and pneumatic hoses),
- they can be used unconditionally in critical environments where dust, moisture, chemicals and aggressive substances can be present in the atmosphere on a daily basis.
- they can withstand high speeds and accelerations.
- Cables can be installed, replaced or installed at a later date.
- Horizontal, as well as vertical, diagonal and circular travel distances are also possible.
- Maintenance work is easy to carry out, but it is generally less maintenance-intensive.
- They require a much lower media length for comparable travel distances, as the media are linear in the cable chain rather than sagging.
The cable chain follows the cable
Cable chains are tasked with protecting and guiding the flexible cables and hoses installed within them. For this reason, chains must always be designed according to the cable/hose features and not the other way round! The more precisely defined the cables/hoses are, the better.
How are cables arranged in the cable chain?
In order to ensure that the cable chain functions smoothly and to avoid any damage to the media, the cables and hoses to be guided, which are relevant for the chain size and composition of the components, should be thoroughly evaluated before selecting the cable chain.
Which cable for the cable chain?
Cables and hoses suitable for cable chains are sometimes flexed very strongly and continuously. As a result, they are permanently exposed to the stresses resulting from the bending movement in the cable chain. Unlike three-dimensional torsional movements, this bending movement is always linear and always in one direction.
The flexibility of a cable has a direct impact on its bending radius, which indicates how much a cable can be bent without impairing its functional capability.
The tighter the bending radius, the greater the stress on the cable and the more difficult it is to achieve the long service life required.
The requirements for the bending capacity of cables and hoses can therefore be defined as follows
These, of course, should comply with the cable chain requirements and the prevailing environmental conditions.
Cable chain cables are characterised by the lowest possible weight. Ultimately, the cable chain must not only support its own weight, but also that of the cables and media hoses placed in it over a length of metres.
Find out more about the outstanding bending properties of highly flexible cables and wires for continuous motion applications.
What other factors are important when selecting a cable chain?
Many factors are of great importance in the cable chain configuration. In addition to the specification of cable chain cables and the consideration of your application environment, the length, speed, acceleration and operating time of the cable chain as well as the weight of the cables must also be determined.
The subsequent arrangement, type of installation and material of the cable chain must also be included in the planning.
You can find detailed information on this in our white paper.
What chain arrangements are possible?
self-supporting arrangements are primarily suitable for smaller cable chain sizes. They are less susceptible to wear than sliding configurations, since there is no friction between the upper and bottom part of the chains during operation. However, the self-supporting length of a cable chain is limited.
As the travel distance increases, the net weight of the cable chain as well as the weight of the cables and hoses placed in it stress the application so that the cable chain can sag in unsupported areas. Sag is not necessarily a bad thing, but it reduces the potential speed and acceleration values of the cable chain.
If the maximum permissible sag value is exceeded, it is recommended that the cable chain is either supported or a gliding application is selected. If a travel distance of more than 10 m is to be overcome, a cable chain with a sliding arrangement and guide channel is usually chosen. Special design solutions (e.g. sliding shoes) minimise the friction effects between chain parts lying on top of one another. The sliding arrangement allows travel distances of up to 100 m and more.
What mounting options are available?
Side mounted application means that the chain works mounted on its side. This configuration is necessary if there is limited space upwards and normal assembly of the cable chains would require too much space. It is also necessary when the additional load of the utilities exceeds the maximum self-supporting capability of the chain, but for some reason the sliding configuration cannot be used.
The following options are available: supported applications where the cable chain is moving on a floor, inside a guide channel, for example in long travel distance applications. Or suspended applications where the cable chain is not supported from the bottom, for example in machine tools.
Vertical assembly means that the direction of motion is vertical and the arc of the chain radius does not touch the ground or the ceiling. For vertical assembly, the chain can either be suspended or brought into operation while standing.
Cables/hoses must be fastened at both ends using the corresponding accessories and should not touch the cable chain.
What material are cable chains made of?
All materials used at LAPP for the manufacture of cable chains are environmentally friendly (RoHS and WEEE). The cable chains are distinguished by the materials used for the chain links and the materials used for the frame stays.
We therefore divide the chains into:
Plastic cable chains are suitable for versatile standard applications in the vast majority of environments (including outdoors) and are also used for increased chain loads in wet and oily environments or for long travel distances. The fastest speed and acceleration values can be achieved with plastic cable chains. Both unsupported and gliding applications or applications with circular movement can be realised with plastic drag chains. They are made from a polyamide-based compound (Brylon 6) and are available as an open or completely closed variant.
By the way: LAPP also offers hybrid cable chains. In hybrid systems, the frame stays and protective covers are made of aluminium. The combination of plastic and aluminium helps to give the chain more rigidity/stability and resistance to harsh environments. Hybrid cable chains are available as open or fully closed variants.
Steel cable chains are suitable for a wide range of applications and especially for environments where plastic is not resistant enough. This is the case, for example, in environments with extreme plus or minus temperatures. This is where steel chains offer a clear advantage over plastic chains.
Configuration options for a cable chain
The majority of cable chain systems are equipped with a single chain. However, they can also have multiple chains. If the number of chains is greater than 1, the chains run directly next to one another, within one another in a ring shape or interlaced. Often, the chain is given a constant, linear direction of movement – a so-called displacement. In many applications, however, rotations inside the cable chain are also required, sometimes of up to 600°. In these cases, a multi-chain configuration is required. There are also countless chain configuration options available for combined movements, i.e. for displacements and rotations.