Linear Chain

1. What's a Linear Chain?

A linear chain SK (LinearChain) or TC (TowerChain) also falls under the category of electromechanical linear drive technology. It consists of specially shaped, highly precise mechanical chain links. Unlike a standard chain designed for tensile forces, the links of a linear chain have so-called shoulders. When an axial force is applied, the chain stiffens via these shoulders, and the resulting form-lock allows for the transmission of compressive forces.

Linear chains are essential components in linear drive technology. They show their true strength in situations where other products, such as screw jacks, linear drives, or screw drives, are excluded due to space constraints.

2. The basic principle: One idea, many possibilities

A load can either be pushed or pulled. Suitable drive elements are either a lifting cylinder or a motor-driven chain. Both options have drawbacks:

1. "Normal" chains can only pull and require two drives for back-and-forth movement.
2. Lifting cylinders are rigid; they can both pull and push. However, lifting cylinders require a retraction space that equals the length of the transfer distance and extends along the same line. Additionally, lifting cylinders need to be twice as long as the distance and are not flexible in tight spaces.

An ideal solution would be a combination of a cylinder and a chain without the mentioned disadvantages, versatile and cost-effective.

Such a versatile tool does exist: the linear chain, which is as flexible as a chain and can also perform the work of a lifting cylinder.

3. How does a Linear Chain work?

Right from the start: The linear chain can operate in both directions—it can pull and "push." This makes it the only chain in the world capable of doing so. What's ingenious for machinery is the chain's ability to coil up, allowing it to be used extremely space-efficiently.

4. How the chain "pushes"

Through the drive element, typically an electric motor, thrust force is applied to the chain links. The shoulders of the individual chain links then press against each other, forming a rigid unit. This allows them to lift or push the load. Thus, the chain becomes a rod that surpasses the cylinder in terms of range, load capacity, speed, and precision. Additionally, the linear chain can be practically "infinitely" long, while a lift cylinder cannot simply be extended.

5. How the chain "pulls"

In the other direction, when pulling, it functions like a regular chain. However, the unloaded part of the linear chain is only half as long and doesn't need to be stored parallel to the travel path. Instead, it can be redirected to a location with sufficient space. The linear chain can be rolled up like a rope. The main advantage is that the linear chain can be coiled and stored where space is available.

6. How does the drive work?

The chain is driven by a chain wheel located in the drive housing. The drive housing not only handles the driving and guiding of the chain but also redirects the chain by 90° or 180°. As a result, the space behind the drive housing is never occupied by the chain. The housing is additionally equipped with a drive shaft, which can be configured on side A, side B, or both sides. This drive shaft allows for the attachment of a geared motor.

To store the chain, a custom storage solution in steel profiles can be provided by the customer. Alternatively, chain magazines, chain covers, or guide rails can be used to handle the task of chain storage.

7. When should a Linear Chain be chosen?

The main focus of the linear chain is on space-saving and achievable speed. The chain's ability to retract allows for applications in confined spaces to be implemented with ease. Speeds of over 300 mm/s are also easily achievable.

8. When is the Linear Chain a poor choice?

Linear chains are economically viable primarily when the space-saving benefits provide significant value. Using a linear chain in standard applications, where alternative electromechanical drives could also be used, often proves to be uneconomical.

9. Linear Chain in action

10. Typical applications for the Linear Chain

If you’re wondering where linear chains can be used, there are a variety of possible applications. For example:

1. In general machinery, medical technology, and automotive engineering
2. Industrial furnaces
3. Sheet metal cold processing
4. Foundries
5. Rolling mills and steelworks
6. Automotive industry
7. Drives in lifting tables
8. Stage platforms
9. Tool and material handling
10. Warehouse logistics
11. Feeding hardening furnaces
12. Cooling systems
13. Modern building technology
14. Conveyor systems
15. Tool changes in metalworking presses
16. Automated guided vehicles (AGVs)
17. Moving freight containers

11. Sizes and options

The linear chain SK (LinearChain) or TC (TowerChain) is available in sizes from 3 kN to 60 kN and is divided into the following types:

1. SK03
2. SK04
3. SK08
4. SK12
5. SK18
6. SK25
7. SK35
8. TC60

The number denotes the maximum nominal load for each chain type (e.g., SK08 = 8 kN). Various standard options are available for the chains, including: Guide rails, chain covers, storage magazines, stainless steel chains (for high temperatures or corrosive environments), hardened chains (for increased lifespan), chain deflections, lubrication systems.

12. Chain lengths

Since a chain is not limited to a certain length of raw material, it can be made up to 20 meters long. However, for chains under pressure, a phenomenon known as "buckling" can occur.

Even if the chain is rated for a nominal load of 8 kN, the length can lead to stability issues. To prevent this, linear chains can be equipped with a guide, and the chains themselves can be fitted with guide rollers. This retrofit results in the types SK03G, SK04G, SK08G, SK18G, and SK35G, where "G" stands for "guided."

13. Pro and Cons