How to turn around 20-foot cargo containers in just 5 minutes - using the linear chain

Cost-effective, space-saving, and disruption-free - the Linear Chain was the best solution here. But how?

Philipp Schmalzhaf - Sales Manager - GROB Antriebstechnik GmbH

by Philipp Schmalzhaf, Sales Manager

Linear Chain used in a Container Mover - GROB Drive Technology GmbH

Thousands of trucks drive across our highways every day, transporting containers. Once they arrive at their destination, the containers must be transshipped. This is where either a crane or a forklift is needed - and an employee to operate these machines. This costs time, money and ties up resources. So not the best choice. A much more elegant solution is the space-saving Linear Chain - made by GROB Antriebstechnik in Sinsheim. Because rail freight has many advantages: safety, climate protection, planning, and reliability. But what happens when the goods arrive at the final station? How does the container get from the rail to the road? And how can turnaround times be minimized, and handling costs kept under control? These are all good questions to which the Swiss company InnovaTrain AG has found convincing answers and developed an innovative solution that has the potential to conquer the world market. The central element of this solution is the Linear Chain by GROB. But first things first:

What's the current situation?

When a freight train arrives at its final destination, the cargo container needs to be unloaded from the train onto a truck. This is typically done using a crane or a very large forklift (reach stacker). However, this also requires a driver, who must be available at the exact moment the truck arrives to minimize turnaround times and prevent handling costs from unnecessarily increasing the cost of transport. It's clear that such a solution is time-consuming, expensive, and inflexible. Therefore, there is a need for a loading concept that is as independent as possible and allows the driver to handle the cargo containers themselves.

Linear Chain for a container mover - GROB Drive Technology GmbH

A genius product now provides the solution

An innovative loading concept with integrated chain conveyors has been in use very successfully in Switzerland since 2011. For example, railCare, the rail logistics subsidiary of the Swiss food wholesaler Coop, has been using the ContainerMover-3000 since 2011 with growing success, and it's only a matter of time before neighboring countries such as Germany, France, or Italy also open up to this groundbreaking technology.

Now, the Linear Chain takes the lead role

In both rail and road freight transport, environmental conditions can be quite harsh. In summer, temperatures can quickly reach 35°C (95°F), while in cold winter nights, they can easily drop to -25°C (-13°F) or even lower. This is why InnovaTrain engineers had a clear requirement for a perfectly functioning cargo container handling concept: "The market demands a simple solution that requires as little maintenance and as trouble-free as possible. Customers want handling times to be as short as possible today," says Beat Wegmüller, Head of Development at InnovaTrain.

The solution needed to be simple, maintenance-free, and trouble-free, consisting of only a few components. The result was an innovative solution with the potential to become a global solution. For with the Linear Chain from GROB Antriebstechnik GmbH in Sinsheim, InnovaTrain engineers found the perfect product for this task. The handling system consists of a lifting and lateral shifting construction that is modularly mounted on the truck chassis. The counterpart on the container mover is the wagon adapter on the wagon, which is secured via the standard cargo container pins and thus connects the construction on the truck chassis to the wagon.

Linear Chain in action - Container Mover - GROB Drive Technology GmbH

The GROB Linear Chain pushes the container from the truck

Fast transshipment in 5 minutes - Thanks to the space-saving Linear Chain

The truck drives to the unloading station. Sensors are used to position the truck at the wagon, the support legs are extended, and the height is adjusted. Under the cargo container are two so-called "mover beams" that are equipped with air bellows. The cargo container is lifted out of the truck's pins using compressed air from the remote control. Now, two pairs of chain conveyors are moved via two hydraulic motors, each of which moves a rolling mover beam laterally towards the wagon. The cargo container stands on the two mover beams and is thus moved from the truck onto the wagon (during unloading). When loading the truck, it goes exactly in the other direction. Now the four chain conveyors pull the cargo container onto the truck. A chain is therefore used here that can both "pull and push".

Container Mover and a Linear Chain - application - GROB Drive Technology GmbH
Container Mover - Linear Chain - GROB Drive Technology GmbH

Before/After

In just a few minutes, the Linear Chain loads the cargo container onto the truck. See the before-and-after image on the left.

The major advantage of the Linear Chain from GROB

Occasionally, the employees at Innovatrain are asked: "Why don't you simply use long hydraulic cylinders for horizontal shifting?" "That was indeed our initial idea back then,' says CEO Pieter van den Bold, "but there's no space for that on the truck because the cargo container needs to be shifted by more than its width – up to 3.2 meters (3.5 yards). Such a task can only be accomplished with a retractable Linear Chain. In each container mover is installed 12 meters (about 13 yards) of the Linear Chain."

The entire handling process, remotely controlled by the driver, takes less than 5 minutes. For this, the Innovatrain system only requires a roadway with a width of three meters (3 yards). Handling can be done at any open loading or connecting track. It's hard to imagine a faster or more cost-effective way to handle cargo containers."

FAQs about Linear Chains

A Linear Chain is a type of chain that can be both pulled and pushed. When the chain links are pushed together, they stay stable and rigid, allowing you to move things forward. It’s often used in machines to lift or push objects.

What a Linear Chain is and where it is used - GROB GmbH chevron_right

Depending on the size, the driving speed is usually below 50rpm.

Yes, lifting systems with multiple chains connected together are common.

The chain of the Linear Chain consists of links that rest on the shoulders and pins of the succeeding link. The chain of the Tower Chain is constructed with U-shaped chain links, providing greater stability and enabling unguided strokes of over 4m.

In standard applications, Linear Chains can be operated with a speed of 250mm/s. Special applications have already been implemented with speeds exceeding 800mm/s.

Yes, the use of stainless steel materials is a common practice for environments with aggressive media.

Yes, depending on the proximity to the product, the chain can also be completely made of stainless steel.

  1. When under pressure load: depending on the control, 100% repeatability can be achieved.
  2. Under changing loads: the control system must consider the backlash at the sprocket and manufacturing tolerances in the chain links.
  1. The load must always be guided
  2. Acceleration should be controlled via a ramp
  3. The chain cannot perform a swiveling movement
  4. The permissible buckling length must not be exceeded

No, within the buckling range, Linear Chains can also be used without guidance.

  1. Electronic bridge: If each lifting element of the system is driven by a motor, electronic synchronization can be achieved through encoders.
  2. Mechanical linkage: More cost-effective and fail-safe are cardan shafts and bevel gearboxes, which can connect all lifting elements of a system together.

The polygon effect occurs when a chain is positively driven by a sprocket. In this case, the chain cannot run perfectly circularly on and off the sprocket, causing deviations in the path of the traction medium. The speed of the chain then fluctuates periodically around a mean speed, which can manifest as vibrations in the chain.

Since the chain undergoes radial movement due to the polygon effect, the guide plates are extended, and minimal play is allowed. This helps mitigate this effect.

No, swiveling movements are not possible with the Linear Chain.

65% with chain magazine, 80% with free chain.

No, the load must always be guided.

There is no calculation basis for this. The buckling length has been determined through tests. You can find a corresponding diagram for horizontal applications here: General Catalog 2023 (grob-antriebstechnik.de). For vertical applications, please contact us.

No, a Linear Chain can never take over the guiding itself. The load must be guided.

  1. Lubrication system: attached lubrication brushes extend the lifespan.
  2. Chain magazine: the chain can be rolled up behind the housing.
  3. Reduction gear: especially useful in lifting systems to reduce torque through gears.
  4. Force sensor: for measuring axial load and protection against overload.

We always recommend using our standard link to connect your load. Utilize all the holes to ensure proper loading of the chain. Dimensions for the front link can be found here: General Catalog

As standard, GROB chains are galvanized. For environments with aggressive media, stainless steel chains can be used.

  1. Standard: 180°C (356°F)
  2. High-temperature continuous: 550°C (1022°F)
  3. High-temperature short-term (under 2 minutes): 1050°C (1922°F)
  1. The load must be guided
  2. The Linear Chain size must be chosen correctly
  3. It should be driven over a ramp

Yes, hardened chain links achieve a lifespan four times longer.

  1. A chain magazine winds the chain in multiple circular paths. Advantage: greater space saving.
  2. A chain cover protects the chain attached to the housing. Due to the attachment, the chain aligns itself and thus halves the stroke length. Advantage: more cost-effective.

Yes, the chain can be stored perpendicular to the lifting movement, such as 90°, or even 180° (parallel) to the lifting movement, as in the case of tool tables. The lift then operates on the table, while the storage runs parallel underneath it.

The T-guide was developed when space for the standard rail above the sliding surface was lacking. In one application example, the customer needed to maneuver with a forklift. The T-guide rail was then embedded in the floor, allowing the vehicles to continue maneuvering undisturbed.

No, you should provide a brake on the motor.

Check for dirt or worn-out parts. Thorough cleaning and, if necessary, replacement of damaged components may solve the problem. If the Linear Chain is noisy after acquisition, system tensions could be responsible.

The different installation positions do not affect the usability of Linear Chains (e.g., through oil sight glasses or similar). By simply changing the mounting side of the mounting brackets, the mounting sides can be adjusted as needed.

There's no calculation basis for this. Tests have shown that for standard chains, 250,000 cycles, and for hardened chains, 1,000,000 cycles represent realistic values.

Question not included?

You can find more application examples and drive solutions here

Linear Chain - GROB Antriebstechnik GmbH

What is a Linear Chain?

Discover the basics of Linear Chains and the impressive technology behind them in our beginner article. We explain how Linear Chains work and the important role they play in various applications. Dive in and learn why Linear Chains are a key component for precise linear movements.

Learn more

Share your application with us! We'll get back to you promptly.

Give us a call:

Or send us an email:

Thomas Moeschle

Thomas Möschle, Key Account Manager