Handling one or two tube bundles simultaneously

The production speed of welded tubes depends very much on the thickness of the tube wall. Thin-walled tubes are produced much faster than thick-walled tubes. In order to be able to handle all products of a tube production line using just one magnet crane, bundles of thinwalled tubes need to be moved around at a sufficiently fast rate.

This is achieved by picking up one heavy or two lighter tube bundles. By doing this not only does the volume handled get adapted to the production speed, but optimum utilisation of the crane capacity is also achieved.

The magnets can either be placed in line for transporting single bundles or offset side by side for carrying double bundles. The lateral movement of the magnets can be automatically set in 7 freely programmable positions and thus adapted to the bundle size

Example applications

Figure 1: Carrying double bundles of thin-walled tubes for efficient loading of trucks at OneSteel in Australia.
 

Figure 2: Clearing the end of a tube production line at Aratubo in Spain
 

Figure 3: Automated warehouse with maximum storage density (no aisles between the racks, stacks up to 6 metres high) at Aratubo in Spain
 

Oblique is possible

Magnetic systems for vertical plate storage are a trend-setting development from TRUNINGER. For highly varied storage systems, they represent a compact alternative to the horizontal storage of plates on the floor: With a single unit, plates can be picked up horizontally or vertically as well as deposited again in the required position.

Figure 1: High storage density with vertical plate storage

High storage density—short transport distances

The vertical storage of the plates massively increases the storage density, shortens the access time and enables direct commissioning of a wide variety of sheet metal. grades from the storage location to the truck or to further processing without additional transport equipment.

Advantages

• The distances between the individual material racks are extremely small thanks to the flat magnet design.
• There is no need to restack the material because storage is sorted by type.
• Commissioning of the individual plates is simple and quick.

Your benefits

• Store significantly more material in the same amount of space.
• Results in shorter transport distances on an average.
• Time savings in plate commissioning.
• One system for all sheet metails according to the motto "One size fits all!".
• Vertical and horizontal storage can be combined with the same system.

Born out of experience: the technology

By using special tilting devices, it is possible to pick up and deposit plates both horizontally as well as vertically. When in basic position, the magnets are suspended vertically in the tilting device. In this position, the crane operator moves the magnets between the stacks of the vertical plate storage system to pick up the plates (see Fig. 1).

Figure 2: Picking up a horizontally lying load

To lift a horizontal load, the magnets must be placed on the load. A rolling mechanism automatically rotates the magnets into a lying horizontal position when they are placed on a horizontal plate. To bring the plate into a vertical position, the magnets must be placed on the outer edge of the plate (see Figure 2).
 

Figure 3: Magnets locked in horizontal position

For the exclusive transport of plates in a horizontal position, e.g. when clearing a firing table, the magnets can be locked in the horizontal position using the chains provided (see Figure 3). This simplifies the handling of the magnets considerably and saves time. Accordingly, these chains must be unhooked again for transporting plates in the vertical position.
Depending on the crane configuration, different crossbeam designs result in the widest possible range of applications for magnet systems for heavy plate transport in horizontal and vertical positions. For very broad plates, oblique storage is often the only alternative for transport on trucks or railroad wagons (see Fig. 4).

Figure 4: Wagon unloading, pickup of broad heavy plate

Even special formed workpieces, e.g. stiffened ship's sides, can be transported to the assembly site without any problems with a vertical plate system from TRUNINGER.

Figure 5: Transport of ship sides at a shipyard

Why redundant system design

Electrical controls are built using a whole bunch of sub-systems which all have a certain potential of failure. To provide safety of the system in case of a single sub-system failure, safety relevant sub-systems are built redundant (double). The two sub-systems working on the same task are cross-checked to make sure, that both systems work fine. Two redundant systems do not add much to safety, if failure of one system is not detected.

Therefore, redundancy, cross-check and safety relevance are part of safety class 3 design concept also referred to in international standardization document DIN-EN 954-1.

Standard redundant components

The concept of redundancy is a central feature built-in Truninger magnet system controls. All safety relevant sub-systems are built according to the safety class 3 standard. The following subsystems are covered:

• Two power sources, mains and backup battery. Backup battery capacity is designed to maintain safe operation for at least 20 minutes.
• Two current sensors and two associated cross-checked signal processing units. Failure of one sensor will be detected and trigger a switch over to battery operation and system lock (magnet can be switched Off but no more On).
• Two power switches, one dedicated to mains power, one dedicated to battery power. Failure of power electronics IGBT (transistors) will cause the second current loop to take over and also lock the magnet system. Both power switches are checked in every load cycle.
• Two controllers built in different hard and software. Any failure of the SmartPick^TM main controller will hand over the control task to the slave controller SafePick^TM. Also here, both controllers are checked continuously by each other.
• Two low voltage power sources. Each of the two controllers is equipped with individual low voltage power sources. Such power sources are cross-checked and both are battery backupped.

Optional redundant components

Most often, the power lines from the controller to the magnet are considered safe and therefore not built redundant. However, in some harsh environments, cables and cable drums can not be considered safe.

If required, total redundancy can be achieved building up two independent electric power circuits to the magnet. Two independent cables, two cable drums, two electric coils in the magnet and two power supplies PowerPickTM build up such independent electric power circuits. Even a short cut at any location of one circuit will not stop this system from operating.

Example: Below is a typical gantry crane installation with an integrated, total redundancy coil magnet system:

Figure 1: Magnet system with total redundancy electrical system
 

The redundant components are:

• Two PowerPick^TM modules.
• Two sets of flat cables.
• Two cable reelers.
• Two independent coils inside the magnet.

This arrangement forms two completely independent end-to-end power circuits which guarantees safety of the load even in the event of partial or complete failure of one circuit.

Also a redundant operator control sub-system ensures that the magnets may be operated from a backup pendant if the radio control unit or radio receiver are faulty.

Easy rotation of large loads

Further processing on slit coils often requires them to be rotated from the horizontal into the vertical position or vice versa.

TRUNINGER has developed magnetic coil rotators for this purpose. Coil rotators offer:

• Easy transport of coils to and from store
• Direct transfer of coils from store to mandrel of processing machine

A coil rotator is an alternative to chains and slings. The magnet grips the slit coil gently on its surface. Maximum contact area guaranteeing the required adhesive force for rotating the coil safely and protects the coil from damage.

Figure 1: 8t coil rotator in position – winding axis horizontal

The magnet is designed in such a way that the coil eye remains unobstructed. The slit coil can thus be pushed straight onto a decoiler without any additional step in the working process.

Figure 2: 8t coil rotator in position, winding axis vertical

Flexibility increases profitability

The QuickChange™ system enables a single crane to use a range of different magnet spreader beams. Controlled remotely by the operator, the lower spreader beams are linked both mechanically and electrically to the upper spreader beams permanently attached to the crane. Product-specific magnet spreader beams are needed for different applications, for instance, in the prefabrication hall of a large sectional steel service centre. 

For moving the individual sections from the warehouse to the saw, sandblaster, processing centre or dispatch area, especially narrow magnets are used, enabling the cranes to work even in tall narrow aisles between the stored material. This enables the user to achieve maximum storage density.

Figure 1: QuickChange™ system with lower spreader beams for handling individual sections in the prefabrication area
 

Switching spreader beams faster and with added ease

The sections are usually delivered by train or ship in packs weighing up to 8,000kg. To keep costs down, these packs of sections need to be unloaded and moved to their respective storage locations as quickly as possible.
Large magnets with a deep magnetic field are used to move the packs around efficiently and safely. These magnets are attached to two further lower spreader beams. To change magnets, first the two lower spreader beams for individual sections are lowered onto their spreader beam stands and decoupled.

Figure 2: Automatic decoupling of the lower spreader beams for individual sections
 

The two lower spreader beams for bundled section packs are then attached. Using a remote control unit or suspended keyboard, the crane operator is able to change the spreader beams within a matter of seconds, without having to bother with any hooks or plugs.

Figure 3: Quick coupling up of the section pack magnets for fast and efficient unloading of trains and ships

Why demagnetisation of the load can be critical

In material handling applications where the steel has to pass though automated processing lines, residual magnetism in the load can cause serious problems. The load may ‘stick’ to machine parts as it travels through the production line or it may attract other small pieces of steel (washers, bolts, swarf etc).
In these situations efficient demagnetisation of the load is essential. SmartPick offers configurable demagnetisation for eliminating a maximum amount of residual magnetism in minimum time.

What happens when steel becomes magnetised?

Ferromagnetic materials such as such as mild or quality steel which have never been subjected to a magnetic field are made up of randomly ordered magnetic ions as represented below in Figure 1. Steel, when in this state, has no magnetic effect on its surroundings (see point a in Figure 3:).

Figure 1: Ions positioned at random (material demagnetised)
 

When a positive magnetic field is applied, the magnetic ions start to fall into alignment. The more powerful the magnetic field, the more tightly the ions are aligned. If all of the ions are aligned as shown in Figure 2:, the material is said to be magnetically saturated (Point b in Figure 3:). For steel the magnetic saturation is equal to 2.4 Tesla.

Figure 2: All ions aligned (material magnetically saturated)
 

However, when the external magnetic field is removed, the ions do not return to their random state. This leaves some residual magnetism in the material, an effect known as remanence (Point c in Figure 3).
This residual magnetism has to be removed by some external means. The actual method applied depends mainly on the magnetic properties of the material. Material such as mild steel loses its magnetism quickly and is said to be ’soft magnetic’. Quality steel on the other hand, loses its magnetism very slowly and is therefore said to be ‘hard magnetic’.
 

RDS (Reverse Degauss System)

RDS demagnetisation eliminates residual magnetism from mild steel. Applying a negative magnetic field causes the magnetic ions to gradually adopt a random alignment. When the opposing field is turned off (Point d in Figure 3:), the ions are randomly aligned, thus eliminating the residual magnetism.

Figure 3: Hysteresis of soft magnetic mild steel

RDS cannot be applied to hard magnetic material because the negative magnetic field causes all the ions to adopt a reverse alignment instead of returning to a random state.

DDS (Downcycle Degauss System)

DDS reduces the residual magnetism in hard quality steel by applying a series of polarity changes in a magnetic field of ever decreasing amplitude as shown below in Figure 4:

Figure 4: Typical magnet current behaviour during DDS demagnetisation

With this approach the magnetic ions are effectively ‘shaken’ into a random state, reducing the residual magnetism to around 2 mT.
Figure 5: shows the resulting hysteresis:

Time is money

Economical and precise picking is extremely important for the steel trade. The TRUNINGER SmartPick^TM magnet control system enables us to meet demanding client-specific requirements for efficient and reliable material picking.

Variable grippers

You need the right approach to have a good grip on things! This naturally applies to magnetic grippers, too. At TRUNINGER the spreader beams and magnets are developed and built to suit each specific task. The model particularly well suited to the task of effective, precise and fast picking is the…

Retractable pole anchor

Developed by TRUNINGER – as simple as it is ingenious! With a retractable anchor integrated into the magnetic pole, the pole surface size can be automatically adapted to the load to be lifted. With the retractable anchor extended, individual bars or small quantities can be picked with ease.

Figure 1: Extended anchor lifts a single section

For large loads or bundles the anchor retracts automatically as the magnet pole is set down onto the surface of the material to be lifted. The whole surface area of the magnet pole is thus then available, ensuring safe, reliable transport.
 

Figure 2: Safely picking a bundle using the complete pole surface

Gentle turning over of slabs

Ongoing development in continuous casting technology has led to nearly all grades of steel now being cast in a single strand. Due to the diverse range of steel grades and the different manufacturing methods the strand’s surface needs to be treated for the next stage in the process. The blank gets further processed, for instance, by flame scarfing or high-pressure grinding. For deburring and grinding the slabs need to be turned over.

Magnet lifting systems from TRUNINGER are an alternative to stationary, hydraulic slab turning devices that require a lot of maintenance. Magnet spreader beams for use in slab turning applications have an especially robust design, making them suitable for cold as well as hot material.

Figure 1: Slab turning magnets taking a slab from a stack for further processing

Figure 2: Turning of a slab using magnets
 

TRUNINGER design features

TRUNINGER designs and manufactures special magnet systems for handling all kinds of heavy loads.

• Robust spreader beam design and durable magnet construction are built-in features of the magnetic systems designed specifically for slab turning applications.
• The magnet beams’ design is adapted to the relevant material specifications. Both individual magnets (see figure 2) and simple fixed beams with multiple magnets are used.
• Specially developed magnets with temperature-resistant coils guarantee a long service life under rugged conditions.
• The magnets are also fitted with reflection plates to protect the coils against radiated heat.
• The magnet control system is fitted with a back-up battery as standard and automatically switches from mains to back-up power in the event of mains failure.
• The entire magnet system can be designed with built-in redundancy, i.e. from the magnet controller via the power supply, right through to the magnet coils, the system incorporates fully redundant components.

Why modularity?

The electrical components of Truninger magnet systems are composed of a number of discrete, separately orderable modules. This multi-level modularity offers a number of benefits:

• It allows mass production of modules based on tried and tested technology
• All cabinets have the same dimensions regardless of function
• All board/component level spares are available from stock
• Many operational features are software configurable
• Ease of integration and maintenance
• Scalability: easy to add extra magnet groups if required

Electrical component hierarchy

 Figure 1: Hierarchy of electrical components
 

Maximum/minimum configuration

Modular cabinet design means the controller can be adapted to suit a wide range of applications. Figure 2 below shows a maximum configuration with battery backup and eight magnet groups:

Figure 2: SmartPick^TM maximum configuration
 

Only two cabinets are required for a minimum configuration supporting a single magnet with no battery backup (cf. Figure 3). This arrangement would be suitable for a scrap magnet application for example.

Figure 3: SmartPick^TM minimum configuration

Remote troubleshooting: quick and easy with cell phone link

When your magnet system develops a fault and technical support is not available locally you can use your Bluetooth-enabled cell phone to establish a direct ’helpline’ link between your system and a server located at the Truninger support centre. Figure 1 below gives an overview of how the link is built up:

Figure 1: Architecture of the remote helpline link
 

The link is setup in two easy steps:

• To initiate the remote helpline setup you have only to establish a Bluetooth connection between your cell phone and the SmartPick unit of your faulty magnet system.
• The SmartPick unit then automatically makes a call, via your cell phone, to the Truninger server using its locally stored subscriber number and APN (Access Point Name).

Once the link with the server is established, a service technician can then ’log in’ to your system to begin fault analysis and quickly determine the cause of the breakdown.

1. What is redundancy?

Electrical controls are built using a whole bunch of sub-systems each having a certain potential of failure. To provide safety of the system in case of a single sub-system failure, safety relevant subsystems are built double, generally referred to be “redundant”. Two sub-systems work on the same task and also cross-check each other to make sure, both systems work fine. Two redundant systems do not add much to safety, if failure of one system is not detected. Therefore, redundancy, cross-check and safety relevance are core elements of safety class 3 design concept also referred to in international standardization document DIN-EN 954-1.

2. Standard redundant components

The concept of redundancy is a central feature built-in Truninger magnet controller SmartPick^TM. All safety relevant sub-systems are duplicated according to the safety class 3 standard.

The following sub-systems are covered:

• Two power sources- mains and backup battery
  Backup battery capacity is designed to maintain safe operation for at least 20 minutes in case of mains power failure.
• Two current sensors—two associated cross-checked signal processing units
  Failure of one sensor will be detected and triggers a switch over to battery operation and system lock (magnet can be switched OFF but no more ON).
• Two power drives—AC/DC & DC/DC
  One drive dedicated to mains power AC/DC and one drive dedicated to battery power DC/DC. Failure of power electronics in any drive such as IGBT transistors will cause the second drive to take over and also lock the magnet system.
• Two controllers built in different hard and software
  Any failure of the SmartPick^TM main controller will hand over the control task to the slave controller SafePick^TM.
• Two low voltage power sources
  Each of the two controllers is equipped with individual low voltage power sources. Such power sources are continuously cross-checked and both are battery backed.

Optional redundant electric circuits

Most often, the power lines from the controller to the magnet are considered safe and therefore not built redundant. However, in some harsh environments, cables and cable drums can not be considered safe.
If required, two independent electric power circuits for one single magnet can be realised. Two cables, two cable drums, two electric coils in the magnet and two power modules PowerPick^TM build up such independent electric power circuits. Even a short cut at any location of one circuit will not stop this system from operating.

Figure 1: Redundant Magnet Controller SmartPick^TM
 

Figure 2: Magnet system on overhead crane
 

Figure 3: Redundant magnet system for bar bundles

A vital troubleshooting tool to minimise your system down time

Similar to the black box recorder of a modern aircraft, all major system events, faults and most operator actions are recorded in an event log. Up to 4,500 individual events can be stored in SmartPick’s non-volatile memory; this corresponds to approximately 200 load cycles of the magnet system.

In case of a breakdown, the events can be traced in detail making the event log a most valuable tool for troubleshooting . Detailed understanding of a problem allows to trigger the appropriate corrective action. Quite often, problems can be solved by telephone or email, saving a lot of time and cost as no specialist needs to rush on site. .

The event log can be accessed by laptop using  SmartPick^TM’s built-in BlueTooth module, nobody needs to climb up the crane (see figure 1 bellow).

Figure 1: Accessing the event log using BlueTooth interface

The event log can be stored in a readable text file and e-mailed to a Truninger support centre for rapid analysis by a system specialist.

Inside the event log

All events logged have a unique event number and carry a date/time stamp; it is therefore possible to determine, to the nearest second, exactly when a particular event occurred. Events cover the following types of information:

• Magnet on/off cycles
• Magnet current and battery voltage
• Use of special features such as Partial Drop (order picking)
• Mains failures and battery switches
• Magnet lifting force selected during material handling operations
• Magnet and environment temperature
• State of crane interface signals
• System information: controller restarts, software versions, system id
• Changes to configuration data

Example: weak battery

The batteries play a critical role in the operational safety of a magnet system. Battery capacity is therefore tested every time the magnets are switched on and when insufficient, power on is aborted.
The following extract of the event log shows an attempt to switch on the magnets when battery test fails due to high voltage drop. Note that the most recent events appear first (so read bottom up for chronological order):

Event: 3398: 214 14:29:48 05.10 RB:chrg enabled 00000
Event: 3397: 145 14:29:44 05.10 Hoist lock OFF 00001
Event: 3396: 147 14:29:44 05.10 Travel lock OFF 00001
** Event: 3395: 012 14:29:20 05.10 RB:Bat test fail 01999
Event: 3394: 206 14:29:20 05.10 RB:bat voltage 00101
Event: 3393: 144 14:29:18 05.10 Hoist lock ON 00001
Event: 3392: 146 14:29:18 05.10 Travel lock ON 00001
Event: 3391: 213 14:29:18 05.10 RB:chrg disabled 00000
Event: 3390: 128 14:29:18 05.10 CB:VG ON 01000

The key events we see here are the following:

• Operator gives command to switch on a magnet (event 3390)
• Measured battery voltage just before battery test is 101 Volts (event 3394)
• Battery test fails because of excessive battery voltage drop (event 3395 data ‘999’)

The difficulty of manual positioning

When using an active telescope to work with different lengths of material you will often need to adjust the spacing between your magnets. In the case of long flexible material such as rebars for example (see Figure 1:), precise positioning can be critical if you want to avoid excessive bending of the load. This can be a safety issue.

The traditional motor control arrangement requires you to operate a 3-position spring-loaded switch (left-stop-right) to start the magnets moving in the desired direction. You must then release the switch (motor stop) once the required position is reached. The entire procedure is manual and correct positioning of the magnets relies on visual judgement alone which can be problematic if you are at some distance from the working zone or if visibility is impaired.

Figure 1: Active telescope transporting different lengths of rebars.
 

Precision and time-saving with auto positioning

With the Truninger auto-positioning feature it is possible to move the magnets to any one of up to eight pre-defined positions. These positions, pre-defined according to the different lengths of material you need to handle, are set up initially by a technician during commissioning of your system but may be re-programmed at any time.

Two different switch options are possible for controlling the auto-positioning:

• The simpler option uses the existing 3-position motor switch. With this arrangement the switch is turned in the desired direction of movement and held in position. The magnets will start to move in the selected direction and stop automatically when the next programmed position is reached. Movement of the magnets can be interrupted at any time simply by releasing the switch.
• A more flexible solution is to install an 8-position rotary switch allowing the target position (0-7) to be pre-selected. The magnets will then be set in motion by activating a springloaded 2-position switch and stop automatically when the pre-selected position is reached. Again, the magnets can be stopped at any time by releasing the 2-position switch.

When auto-positioning is activated the InfoPick display changes as shown below in Figure 2: 

Figure 2: InfoPick display during movement of magnets

The rotating green element indicates movement of the magnets; the yellow elements display the programmed text corresponding to the target position (3-6m in this example).

When the magnets stop at the target position the InfoPick display changes as follows:

Figure 3: InfoPick display when magnets reach target position

This remains for 3 seconds after which the InfoPick display reverts to the state it was in prior to activation of the auto-positioning.

Special devices

Our extensive experience of different applications as a magnet system manufacturer allows us to offer solutions for special projects as well as standard applications (see ‘Custom spreader beams’ document). One such solution created in response to customer-specific demands is our safety gripper.
TRUNINGER magnet systems are equipped with every conceivable mechanical and electrical/electronic safety feature as standard in order to achieve maximum safety levels when handling material magnetically. A load lifted with magnets could actually be secured to the spreader beam with chains.
However, this would be very time-consuming and potentially dangerous as workers would have to approach the suspended load to attach the chains. This is why TRUNINGER developed the safety gripper.

Figure 1: Safety gripper with secured load
 

An open/close mechanism remotely controls the safety gripper. For handling reasons the safety gripper should be only slightly wider than the magnets as any extra width would have a negative impact on storage density, speed of access to material, deadweight, operability, etc. The safety gripper is therefore ideally suited for use with long products.

As the magnets grip and lift the material, the safety gripper is in the open position. Once the load has been lifted, the gripper is closed. The load then continues to be carried magnetically. The safety gripper is only used in an extreme emergency, i.e. in the event of the magnets dropping the load.

If necessary, the gripper can also be coupled to the crane’s operation, i.e. it can be made impossible for the crane to move if the safety gripper is not fully open or closed.

Simplicity, safety, flexibility

Basic operation of the magnets is reduced to a simple ON/OFF action from the operator station. To minimise the risk of accidental power off, switching off the magnets is always a two-handed operation requiring the simultaneous pressing of two separate buttons: OFF and ENABLE (see controls 2 & 3 in Figure 1:), located on opposite sides of the operator station.
In multiple-magnet systems you may choose to switch on or off all or only selected magnet groups (see group buttons 4 in Figure 1).

Magnet and crane controls in a single unit

In the case of overhead cranes operated from the factory floor the magnet and crane controls will generally be integrated into a single radio remote control unit similar to the one shown in Figure 1:

Figure 1: Typical radio remote control unit for crane and magnets

Automatic handling of crane interface functions

Automatic handling of crane interface functions To ensure safe, seamless interworking with the crane all basic crane control signals and interlocks are handled automatically by the SmartPick^TM unit. The following crane interlock signals are provided as standard and prevent or restrict movement of the crane if the magnets are not in the appropriate state:

• Hoist Lock: prevents activation of the crane hoist if the magnets have not reached a stable power setting. During power-up the first stable power state corresponds to the preselected Partial Load level. When the operator issues the power-off command, the crane hoist remains locked until the magnet current has reached zero.
• Travel Lock: the crane travel is immobilised or restricted to slow speed until the magnets have switched to full lifting force (Full Load).

As an additional safety feature, if the crane provides a LOAD SUSPENDED signal SmartPick^TM will ignore a magnet OFF command issued while a load is still suspended.

Working with reduced power

It is not always necessary or desirable to use the full lifting force of the magnets. For example when you want to lift small quantities of a material or selectively drop certain items such as plates, you will need to reduce the magnet power. There are two ways of controlling magnet lifting force:

• Pressing the ON and ENABLE buttons together (cf. 1 and 3 in Figure 1) will cause the magnets to switch to the pre-selected partial load setting. The magnet lifting force can then be further adjusted by turning the rotary selector switch (cf. control 5 in Figure 1).
• Once the magnets are in partial load, the lifting force may be gradually reduced by keeping the ON button pressed. This operation (Partial Drop) is convenient for plate handling when you need to drop only the bottom few plates.

Where automatic storage of long products is not economical, storing material in stacking cradles can be a useful alternative. In situations where small volumes or small quantities of material are stored and transported, what is needed is often just a lifting system which allows:

• Easy access
• Low space requirement
• Simple operation

Using a stacking cradle system it is possible to store large quantities of material in a very compact space. Such a storage system is the ideal, flexible solution for space-saving, safe storage of long and/or flat material as well as products in large quantities.

Figure 1: View of a typical stacking cradle storage system

Cradle carriers fixed on the magnet beam allow several operations with the same system:

• Rapid loading of the bundle into the stacking cradle
• Simple mechanical re-stacking of cradles
• Precise order picking of individual items using the magnets

By using the cradle carrier system to alter the stacking order, material lower down is always accessible. There is no longer any need for any manual rearranging.

The magnet system’s cradle carriers are located between the two magnets of a magnet group. The lugs are swivelled out by a motor.

Figure 2: Mechanical restacking of a cradle
 

Before order picking with the magnets the motor swivels the lugs back. The entire cradle carrier is no wider than the magnets. Long material can therefore be picked without any obstruction.

Figure 3: Order picking from the stacking cradle
 

For structural reasons a different cradle carrier design is needed for wide or flat loads. Here the carrier lugs no longer get swivelled out. Instead a motor rotates the entire carrier mechanism.

Figure 4: Carrying cradles using rotatable carrier mechanisms