Stacking Cradles
Time saving as an advantage
By using a TRUNINGER magnet system you save not only space, but lots of time as well.
Magnets, when properly operated, allow you to:
- Approach the load quickly and reliably
- Grip the load securely
- Lift the load from its storage location in a few seconds
Magnet systems also enable everything in the warehouse to be tightly packed, which results in shorter average crane travel distances and therefore saved time.
Handling more material in a small space
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
Magnet system with cradle carriers
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
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Slewing magnets
Flexibility and safety
Flexible movement makes it possible for the magnet spreader beam to be adapted to users’ varying requirements. Magnet slewing plays a central role in this.
Slewing magnets are used not only because of their great adaptability, but also because they play an important part in magnet systems’ ability to handle materials safely.
The magnets are slewed, either manually or by motor drive, before they are set down on the load. Slewing magnets are extremely useful in the following situations:
Many different materials—one magnet system
It is often necessary to lift various loads of differing dimensions using one and the same magnet system. A typical such application would be handling steel bars and sheet metal in the same bay of a warehouse. The magnet spreader beam needs a high degree of versatility to adapt to the various dimensions and different materials.
For steel bars the magnets are positioned parallel to the load, while for carrying sheet metal they are slewed 90 degrees.
Figure 1: Magnets slewed 90° on a pack of sheet metal
Figure 2: Magnets turned parallel to the load, lifting a bundle of pipes
Varying material widths – high-density storage
A profitable warehouse succeeds when offering a good range and mix of products. Consequently material of different shapes, lengths and widths are found in the storage area and each of them makes different use of the space. The warehouse will yield higher returns when all products are stored as compactly as possible and when the product mix does not consume too much space.
Slewing magnets help to increase storage density by adapting to the width of each material. For narrow loads or individual bundles the magnets are placed parallel to the load. For wide loads or for lifting more than one bundle at a time the magnets are slewed.
Figure 3: Slewing magnets lifting three bundles of pipes simultaneously
Safety when lifting wide loads
The magnets used for beams or sections are very slim, allowing to pick single beams even in narrow gaps. Spaces between material stacks and between aisles are deliberately avoided in order to reduce cost.
In a warehouse for beams or sections the material is stored in many different sizes. I-beams of both 100 and 1,000mm in width may be found. For wide beams, setting the magnets down in the middle is difficult to achieve. Positioning the magnets at an angle prevents the load from tilting about the long axis when picked off-centre.
Slewing magnets are thus a basic requirement for transporting the load safely!
Figure 4: Slewing magnets placed at a slight angle on a wide load
Load temperature > 120°C
Example: Hot billet handling up to 600°C
Thanks to the transport of hot material, sequential processes in the steel mill can run “with the same heat”. This means, that material does not need to be heated up again for further processing, thus saving considerable time and energy.
Figure 1: TRUNINGER magnet system for billets up to 600°C
General Considerations for Handling Hot Loads
For magnetic handling of hot loads a number of physical properties and design issues need to be considered:
- Steel loses all of its ferromagnetic properties at temperatures above 768°C.
- Hot metal products are not as stiff as cold products. The increased flexibility of the product results in more deflection. This increased deflection needs to be carefully considered in the design of a suitable magnet handling system.
- At load temperatures of 600°C, the lifting force of the magnet is significantly reduced compared to the force generated at 20°C.
- Special precautions must be taken to protect the magnet electrical coils from the heat.
- The design of any magnet lifting system needs to be as simple as possible. Active (motorised) spreaders require motor drives which in most cases are not capable to withstand constant exposure to high temperatures. Lubrication of moving parts is also difficult due to unstable lubricants.
- Devices such as proximity switches or sensors are also generally unreliable when constantly exposed to high temperatures. Sensors must be either removed or protected against the heat.
TRUNINGER “HOT” Magnets
Our long term experience as a manufacturer of magnet systems allows us to offer a wide range of magnet lifting solutions for hot load handling. Thanks to the following features, hot loads at temperatures of up to 600 °C can be transported safely:
- Magnet electric coils potted with high temperature resistant compound
- High temperature resistant insulation material
- Reflective plates to protect the magnet from radiated heat
- Thermal insulation layers within the magnet to separate the magnet coil from the heat
- Magnet housing designed for passive cooling
- Heat resistant power supply cables with additional heat protection device
Slewing Device
Compact but rugged
There are a number of reasons why it may be necessary to rotate a load:
- To achieve optimum alignment on a truck, train or ship
- To get high storage density in a warehouse
- To handle different alignment of material in the stock or in production
- To scan loads for automatic identification devices (e.g. barcode readers)
- A motorised load slewing device allows the load to be rotated by remote control
Rotating a load during transport can be done in two ways:
- By a slewing crab on the crane
- By a slewing device on the spreader beam or on the magnet itself
Note:
Slewing devices often add significantly to the cost of magnet systems or cranes. If you have the option to plan your storage layout, it is therefore very advisable to consider a fix alignment of material, machines (processes) and transport (trucks). This will not only safe investment costs but also reduce cycle time.
Slewing trolley on cranes
Cranes with a slewing trolley replace the corresponding device on the magnet side. This leads to lower weights and cost of the magnet system.
Figure 1: Slewing trolley on a crane
Slewing device on magnet system
A load slewing device on the magnet or spreader beam side makes sense when the footprint of such device does not collide with narrow gaps in the store area.
Figure 2: Magnet spreader beam with load slewing device
Load slewing on magnet
For special applications, it is also possible to place a load slewing device on a single magnet. Load slewing devices are often used with coil magnets; this allows coils to be turned remotely.
Power can be supplied to the magnet within the load rotating mechanism by means of slip rings, if required. This avoids a limitation of the rotation range.
Figure 3: Load slewing device in combination with a coil magnet
QuickChange™
Flexibility for singles and packs
The QuickChange™ system enables a single crane to use a range of different magnet spreader beams.
The lower spreader beams are remotely coupled with the permanently installed upper spreader beam, and the mechanical and electrical connection is made automatically.
Such as the system bellow:
A slim magnet system designed for single beams is used to enter in-between narrow stacks in the warehouse. Storage can be arranged compact and high, resulting in small space consumption and high handling speeds.
Figure 1: QuickChange™ system with lower spreader beams for handling individual sections
Change spreader beam in shortes time
This customer gets his sections delivered by train in packs weighing up to 8,000kg. Handling of such packs surpass the capacity of the slim single beam magnet system above.
A second magnet system featuring large magnets with a deep magnetic field is used to move the packs. A common interface allows to interchange the two magnet systems. Coupling and decoupling to the crane is done at the press of a button, both mechanically and electrically.
Figure 2: Automatic decoupling of the spreader beams for individual sections
The crane operator interchanges the two magnet systems within a few seconds. No manual work on any hook or plug is required.
Figure 3: Quick interchange of two different magnet systems
Removing residual magnetism
Leaving no traces
Demagnetisation
Residual magnetism in steel can cause serious problems. The material may ‘stick’ to machine, small pieces of steel (washers, bolts, swarf etc) can adhere to the transported material or welding arcs can be ‘blown‘ or ‘deflected‘.
Efficient demagnetisation of the load is essential. Our magnet controllers perform extensive and fast demagnetization processes. This reduces residual magnetism to a minimum in the shortest possible time.
What happens when steel becomes magnetised?
Ferromagnetic materials which have never been exposed to a magnetic field consist of randomly ordered magnetic domains such as shown below in Figure 1. Steel, when in this state, does not show any magnetic effects (corresponds to point a in Figure 3).
Figure 1: Magnetic domains positioned at random (material demagnetised)
When the material above is exposed to an external magnetic field, the magnetic domains start to align. The stronger the outer magnetic field, the better alignment we get. If all of the domains are aligned as shown in Figure 2, the material is magnetically saturated (Point b in Figure 3). Saturated steel goes allong with magnetic field strength of about 2.4 Tesla.
Figure 2: All magnetic domains aligned (material magnetically saturated)
Unfortunately, the magnetic domains do not return to their random state when the external magnetic field is removed. This results in residual or permanent magnetism remaining in the material (see remanence Point c in Figure 3).
To remove such residual magnetism a demagnetisation process needs to be applied. The external field is not just removed but follows a certain fluctuation in time and strength. The magnetic domains are kind of ‘shaken‘ which causes their uniform alignment to fall apart. Such method needs to match the magnetic properties of the material. Mild steel quickly loses its magnetism, a material property refered to as ‘soft magnetic‘. Quality steel on the other hand, is ‘hard magnetic‘ and more difficult to demagnetise.
RDS (Reverse Degauss System)
RDS demagnetisation is designed for quick elimination of residual magnetism in mild steel. Applying a negative magnetic field causes the magnetic domains to gradually adopt a random alignment. When the opposing field is turned off (Point d in Figure 3), the residual magnetism is elimated to a vast extend.
Figure 3: Hysteresis of soft magnetic mild steel
DDS (Downcycle Degauss System)
DDS reduces the residual magnetism for hard magnetic materials. A series of polarity changes in a magnetic field with decreasing amplitude is applied as shown below in Figure 4:
Figure 4: Typical magnet current during DDS demagnetisation
The magnetic domains are effectively ‘shaken‘ into a random state, residual magnetism is reduced down to typically 5 mT corresponding to about 0.1% of field strength of saturated steel. This is well bellow the critical levels causing the problems above. Figure 5 shows the resulting hysteresis:
Figure 5: Hysteresis of hard magnetic quality steel
FE method
Magnets do not only need to lift weights, they also must be safe in case of application specific imperfections and disturbances. Magnets are never in perfect contact to the load. Dirt, ice, metal chips, packing materials, strappings, surface coatings and also load deflections force an air gap between magnet and load.
Such effects must be taken into account to make a magnet not only strong but also safe. Magnetic fields must penetrate such air gaps and match customer specifications also in the presence of such imperfections. For magnet design, TRUNINGER uses finite element simulations to optimize existing magnet designs as well as to develop new, customer-specific magnet solutions. Lifting force, magnetic penetration depth and air gap compatibility can be simulated for smooth implementation of customer specifications from theory to practice.
Figure 1: FE-simulation, I-beam bundle under lifting magnet
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Transport of two Tube Bundles
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 automatically be set in 7 positions and thus be adapted to the bundle size
Example applications
Figure 1: Carrying double bundles of thin-walled tubes 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 at Aratubo in Spain
Vertical Plate Storage
It also works vertically
Magnetic systems for vertical plate storage are a pioneering development from TRUNINGER. In highly diversified warehouses, they represent a space-saving alternative to horizontal floor storage of plates: With a single system, plates can be picked up horizontally or vertically and be placed in the required position.
Figure 1: High storage density with vertical plate storage
High storage density
High storage density - short travel distances
Vertical storage of the sheets massively increases the storage density, shortens the access time and enables a wide variety of plate qualities to be picked directly from the storage location onto the truck or into further processing.
The use of special tilting devices makes it possible to pick up and place sheets both horizontally and vertically. In the basic position, the magnets hang vertically. In this position, the crane operator moves the magnets between the vertical stacks of plates for pick up (see Figure 1).
Figure 2: Picking up a horizontal load
To lift a horizontal load, a rolling mechanism automatically rotates the magnets into a horizontal position when they are placed on the load. To lift the plates into the vertical position, the magnets are placed on one side of the plate (see Figure 2). For horizontal transport of the plates, the magnets can are place in the middle of the plate.
Figure 3: Magnets locked in horizontal position
For the exclusive transport of plates in a horizontal position, e.g. when clearing a flame cutting machine, the magnets can be locked in the horizontal position using a set of chains (see Figure 3). This simplifies the handling and saves time. Accordingly, the chains must be unlocked again for vertical transport.
Figure 4: Wagon unloading, pickup of wide heavy plate
Even special formed workpieces, e.g. stiffened ship's sides, can be transported to the assembly line without any problems using a vertical plate system from TRUNINGER.
Figure 5: Transport of ship sides at a shipyard
Coil Rotator
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 placed straight onto the mandrel of a decoiler without any additional step in the process.
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Figure 2: 8t coil rotator in position – winding axis vertical
Retractable Pole Anchor
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 ingenious! With a retractable anchor integrated into the magnetic pole, the pole surface size can automatically adapted to the load. 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 magnet is further set down. The anchor retracts automatically so that the entire pole surface comes into contact with the load. This way, even lager loads can be transported safe and reliably.
Figure 2: Safely picking a bundle using the complete pole surface
Slab Turner
Gentle turn over of slabs
Due to the diverse range of steel grades and the different manufacturing methods the slab's surface needs to be treated for the next process in production. Further processes are, for instance, 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. 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 moving a slab for further processing
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Figure 2: Turning over 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 fix length spreader 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 heat radiation.
- The magnet control system is fitted with a back-up battery as a 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 lines, right through to the magnet coils, the system incorporates fully redundant components.
Modular Design
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: SmartPickTM 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: SmartPickTM minimum configuration
Remote Helpline
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.
Redundant Magnet System
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 SmartPickTM. 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 SmartPickTM main controller will hand over the control task to the slave controller SafePickTM. - 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 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.
Figure 1: Redundant Magnet Controller SmartPickTM
| SP | Module SmartPick (SP), Nr. 1 CPU controlling AC/DC drive, signal inputs, redundant low power supply |
| SA | Module SafePick (SA), Nr. 2 CPU controlling DC/DC drive, battery charger, battery supervision / maintenance (automatic capacity test) |
| PP 1 & 2 | Module PowerPick (PP), generates safe DC Power for magnet uniting mains- and battery power drive |
| InfoPick | Module InfoPick, graphic display informing the operator and staff on the ground visually and acoustically about the state of magnet system |
| Operation | Two operation units can be connected to SP, if one of operation unit fails, another unit can be used as backup |
| Magnet Coil | Redundant magnet with double coil each connected to one PP module, this results in safe power supply keeping up sufficient magnet force in case of any power circuit Coil failure |
Figure 2: Magnet system on overhead crane
Figure 3: Redundant magnet system for bar bundles
Black Box / Event Log
Fast troubleshooting, short 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 SmartPickTM’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’)
Auto-positioning of Magnets
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.
Easy operation
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 SmartPickTM 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 SmartPickTM 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.