Shuttle Storage System Part 3 – Layouting

Shuttle vehicles and rails must be designed in a space-saving way, in order to reach a profitable height grid. The height of the rail is decisive for the reachable space utilisation, because the height arises in every storage level and the totes are stored with a greater, vertical distance as actual necessary. Thus, the space utilisation and the storage capacity are less than those of lifting beams or miniloads – also because of the need of vertical conveyors. On the other hand, the floor space required is almost the same. The rail usually features a high integration of functions. It combines the function of positioning, energy transmission, carrying and guidance of the shuttle as well as safety functions. The data transmission is normally done via WiFi or Bluetooth. The rack has to be realized in that way, that it is able to absorb the occurring force of the movement, even in the case of error. Consequently, the costs for this kind of rack are higher than those for systems, which don’t cause forces or only small forces into the rack.

Shuttle Storage System Part 2 – The Basics (2/2)

A shuttle storage system consists of the following components:

– Shuttle vehicle with or without lifting functionality (MLS or OLS Shuttle)
– Vertical conveyor
– Railing system
– Rack
– Load
– Controls
– Transfer conveyors

Shuttle vehicles, which – regarding the design – aren’t bound to a specific aisle, can move themselves autonomous and therefore take functions in different levels or aisles of the rack. Therefore appropriate transfer devices are necessary. Shuttle vehicles can also be the replacement for automated conveyor systems, in order to bridge transport routes outside of the rack. Accordingly, the design of the shuttles must be appropriate for leaving the rack and moving on the industrial floor or on a rail system.

Shuttle Storage System Part 1 – The Basics (1/2)

Shuttle storage systems are used to store or to buffer totes, cardboard boxes and shelf boards. Static line racks are referred as shuttle storage system, in which autonomous shuttle vehicles operate. Every single shuttle vehicle operates in one or in several rack levels, but not in all. Shuttles, which operate in several rack levels, feature a lifting function. Vertical conveyors are used to connect the rack levels. Those can either relocate the shuttle vehicles in another rack level or convey the load to the level of the pre-storage area. Shuttle storages are used preferably for highly dynamic applications and are assigned to the automated small-parts warehouses. Thus, they represent an alternative to the conventional storage system with lifting beams – or miniloads. Advantages arise with the possibility to scale the performance of the system by varying the number of shuttles. Hence, it can be reacting to peak demands and changeable capacity utilisations. The loading is done by load handling devices (LHD), as they are known from the miniloads. However, the LHD are optimised in reference to the application of shuttle systems. Therefore, the flexibility concerning different goods is given. Depending on the LHD different rack types must be used.



The ABC of the shuttle storage systems – 10-part blog series!

We present you the basics of the shuttle technology in our 10-part blog series, we explain the difference between shuttles and miniloads and we go into detail about the future of both, partly rival systems. Especially, shuttle systems become increasingly popular, but is their usage useful at all time? Is the miniload “out of fashion”? This and a lot of other questions we are going to amplify in the course of the blog series.

Flow Rack System – Driven By Gravity Or Safety?

Powered flow rack warehouses for pallets, unit loads and trays up to 1500 kg are based on the renowned GEBHARDT pallet accumulation conveyor type 525 – which has been synonymous with robust handling and energy efficiency technology for decades.


This system has many benefits. Space is used optimally since the lanes do not Need to decline. There is also a low profile construction. The warehouse works according to the first-in first-out principle. This ensures that the goods stored first are also removed from the warehouse first. As compared to the gravity systems, the GEBHARDT flow rack warehouse offers a much higher amount of safety for both the goods and the staff. The system works without a decline; brakes cannot fail; it works without line pressure and guarantees safe removal of the pallets even with damaged running rails. The warehouse has a load side and removal side. This leads to short travel and efficient work. The warehouse also can be expanded virtually without limitation. The flow rack channels can be 10 m or 100 m long. – No decline needs to be considered.

Sorting and Supply with AS/RS Supply T-Car e.g. with pallet lifter


The powered flow rack warehouse offers safety that is only possible with a powered horizontally placed flow rack system of accumulation roller conveyors. This means comprehensive safety for pallets with heavy and light conveyed goods and for the people who operate the warehouse. GEBHARDT accumulation roller conveyors guarantee safe continuous operation as every single roller is powered. The pallets are transported on powered rollers and accumulate automatically with zero line pressure. No „braking“ – therefore also no danger that pallets break free and hit the floor with destructive force.

Technical Features

  • Horizontal flow rack channels – each carrier roller is driven
  • Drive of several channels by a common motor – Drive parts like chains and gears are protected in the frame profile
  • Secure, smooth pallet transport – conveyor speed 0.2 m/s – each flow rack channel is designed as an accumulation roller conveyor
  • Lowest power demand, only approx. 5 Watt per pallet – no group transport

Examples of application

  Chemical industry

  • Powered flow rack system with 3 levels and 17.5 m long channels
  • Feeding with an ASRS
  • Removal with a forklift truck
  • Storage capacity for 504 pallets, each with a weight of 500 kg
Food industry
  • Powered flow rack system with 2 levels for pallets
  • Top level for storage, lower for load supply
  • Top: Fully automated feeding by conveyor system, removal by lift truck
  • Lower: Feeding and removal by forklift truck
  • In the same company there is a second double level flow rack system with a storage capacity of 1000 pallets and an hourly capacity of 60 pallets. The lower level lies has a height of 2 m. The space beneath is used for stowing the partial pallets and for order picking. The feeding of the flow rack system takes place automatically by an AS/RS. The removal is carried out by a lift truck.
Beverage industry

Powered flow rack system for beverage pallets 1000 x 1200 x 1800 mm. Three levels, one on top of the other, 45 m long. Fully automatic in-feeding by an AS/RS system. Removal by a lift truck. ASS removal is planned within the framework of an expansion. A warehouse update by a material flow computer with integrated printer and screen provides constant information on the stock levels of 25 beverage types.

Warehouse capacity
approx. 2000 Pallets
Conveyance capacity
100 Pallets/h
Conveyor speed
0,2 m/s
Total drive output
10 kW

Energy Efficiency In Intralogistics: Lowering Costs, Protecting The Environment.

In the scope of the Blue Competence sustainability initiative of VDMA, an intralogistics technology supplier takes on board responsibility for economy, ecology and society. The objective is minimization of the energy and resource consumption by innovative Technology.

Opportunities for optimization of energy consumption
Energy consumption not only depends on the automatic conveyor and warehouse technology. The greater part of the energy consumption relates to heating/ventilation, lighting and other consumers. Therefore, it is necessary to choose a holistic approach when energy consumption should be reduced. Beside to the conveyor and warehouse technology the building technology is important. The processes and procedures of the operation of an automated system also have great influence.

Lowering costs, protecting the environment

The Blue Competence initiative of the VDMA helps to find sustainable products and companies who adopt sustainability. GEBHARDT decided early on to place its products and services under the Blue Competence flag of the VDMA. It has always been our objective to develop machines that keep the energy consumption as low as possible. This objective becomes more and more important particularly in times of increasing energy prices. GEBHARDT combines innovative software with advanced mechanics to achieve this objective. Optimization that only includes individual components utilizes only a small part of the optimization potential. In intralogistics the overall system must be monitored. The reduction of energy consumption often goes hand in hand with the also welcome effect of wear reduction. Both together reduce the operating costs and make the logistics center more efficient.

Suppliers of automated intralogistics systems have many opportunities to influence the energy consumption of the logistics center:

Light-weight construction

Especially in the area of warehouse technology it is important to implement targeted lightweight, because the reduction of the moving mass is the first step to reduce energy consumption. Extensive simulation tools, such as FEM, are necessary in the product development. This leads to the use of innovative materials and bonding techniques, such as gluing. The composite-miniload Cheetah is the pioneer in this industry here.

Dynamic adjustment / run on demand

The energy usage in logistics centers and thus also in automatic small-parts storage can fluctuate considerably during the course of the day. There is a great savings potential here. Smart dynamics adjustment allows for energy saving particularly in the traveling axis. Smart algorithms analyze the order loading and automatically adjust the dynamic parameters of the warehouse technology. Also conveyor technology should only run if there is something to convey. Therefore it is important to integrate an intelligent shutdown of drives. The dynamics of the conveyor system can be adapted to the order situation. Intelligent software ensures that the performance of several intralogistics components is synchronized and matched to each other. So, only the energy is consumed, which is actually needed.

Interim circuit coupling at AS/RS

The interim circuit coupling represents smart control of the traveling and lifting axis. The objective is to achieve the minimum traveling and lifting time for a maximum number of double cycles with the minimum energy consumption. The energy that is released, e.g. when the traveling axis is braked, is diverted to the lifting axis to supply the required movement of the lifting axis. This solution pays off immediately and reduces energy consumption by up to 20%.

Energy recovery at AS/RS

The energy generated in the movement and positioning energy released in the system is connected via the mains feedback device and the interim circuit of the frequency inverters. Generated energy that cannot be used in another axis can be fed back into the mains. This technology permits ASRS to save up to 50 % energy. Amortization with pallet handling ASRS is at approx. 2 years.


Smart software for saving energy comprise various functions. In addition to the dynamics adjustment, the path to be travelled must be minimized, e.g. by ABC analysis. The work load management can ensure that auxiliary processes like relocations are performed in times of low work load, e.g. at night. The storage and relocation strategies must be optimized for each individual application.

Continuous improvement

Energy consumption of a logistics center can be continually improved. The improvement process must be continually revised and updated. The starting point is the evaluation of consumption data, followed by a search for potential improvements. Efficiency is increased once potential savings are identified. The results must be measured, visualized and monitored before the process is instigated.

Lightweight construction for miniload cranes: Evolution or revolution?

RBG CheetahFor many years, the lightweight construction  for storage and retrieval cranes is driven by the requirements of performance and energy efficiency. There is a trade-off between operations and design in an automatic small parts store. A modern storage and retrieval crane has to provide a better performance without deteriorating the cost advantage and the storage capacity. An increase in the performance requires higher driving dynamics of the storage and retrieval crane, which requires a larger volume and a stiffer supporting structure to give a reduced calming time. This however leads to a deterioration of the approach dimensions and a reduced storage capacity. With the same volume of the supporting structure, the stability without changing the approach dimension can be implemented by an antipedalgear. This however leads to higher acquisition costs and reduced availability caused by an additional technical expense. Similarly the stiffness can be increased due to the lightweight construction with new materials, like Carbon Fibre Reinforced Plastic (CFRP). So the energy consumption as well as the stress of susceptible components will be reduced, what leads to a reduction of the operating costs and the availability. The acquisition costs will be significantly higher  using CFRP. The evolution of familiar concepts , which rely on the use of thin-walled, edged or rolled metal structures, are reaching their limits with an increase of dynamic. This shows, for example when there are problems with the fatigue strength and results in cracks in the metal. This is why GEBHARDT decided to go a revolutionary way and rely on composite materials. The result is the GEBHARDT Cheetah.

Up to now the implementation of a consistently lightweight construction with composite materials failed because of the high material- and manufacturing costs. That’s why the implementation of the Cheetah-mast is made of standard profiles of composite materials. The critical buckling of the large volume mast can be prevented with the use of profiles in the thrust range of the mast. The storage and retrieval crane is made of different materials, mainly steel, aluminum and composite materials. This material mix breaks down the previous problems with composite material concepts in storage technology.  Because the adhesive bonding has proved to be a good joining technology for different materials, a suitable surface pretreatment and  adhesive technique was developed. Equally the adhered materials were checked regarding their aging, to guarantee a permanent bond. Adhesive Bonding is especially advantageous in comparison to welding, because there is nearly no thermal deformation which has to be corrected. Also the adhesive is using the complete contact surface of the joining members – e.g. in comparison to spot-welding. Furthermore the adhesive gives a higher damping to the overall structure, so the storage and retrieval crane gets an improved calming time after slowing down. Besides the development of the new product, Gebhardt also had to implement new technologies for the manufacturing process. Up to now the multi material mix and especially the use of composite materials were used rarely in intralogistics. To check the operational stability and the operational safety of the new storage and retrieval crane, the mast was tested on a servo-hydraulic vibration test rig. It proved it’s stability even after a few millions of load change and showed no damage at all. Testing also included tens of thousands of collisions with the buffer and emergency stops. That’s how the test stand trials and aging test reflect the whole life cycle of the Cheetah.