Spreader types

Robust simplicity

A fixed spreader beam represents the simplest possible magnet beam design. The main feature is it's simple and robust structure. Most often,  such spreader beam can be built without any – or very few – moving parts, which underlines the unpretentiousness of this solution.

Benefit 1  Low maintenance costs
 

Figure 1: Simple fixed spreader beam for lifting large round steel bars
 

In particular for long spreader beams, low dead weights can be achieved by means of a honeycomb design (see figure 2).

Benefit 2  Low dead weight of the magnet gripper, less wear of the crane

Hooks for conventional material handling – for example, using chains and ropes – can be added at any place along the fixed spreader beam. The same applies to additional mechanical devices, such as stacking cradles, safety grippers, quick-change systems etc. (see figure 2).

Benefit 3  Universally adaptable
 

Figure 2: Fixed spreader beam with three magnets, using honeycomb design and equipped with a quick-change system
 

A fixed spreader beam can be provided with additional auxiliary functions such as:

• Slewing magnets
• Travelling magnets or magnet groups
• Load tilting device
• Load slewing device, etc.
   

Figure 3: Fixed spreader beam with travelling magnet groups
 

A properly designed fixed beam is usually simple, robust and relatively inexpensive.

Selection criteria for the fixed crosshead

Fixed spreader beams are a good solution for steel handling processes when the following conditions apply:

• The material to be handled is:
  • of uniform length, or
  • differs only slightly in length
  • and is sufficiently rigid
• Two points of suspension are available on the crane side
• The material orientation is:
  • either parallel to the crane bridge
  • or parallel to the crane way
• The material is slewed during transport using a slewing gear

Driveless telescopic beam

A passive telescope is used when cranes are equipped with two independent trolleys. A three-piece telescopic beam connects the two sub-spreader beams and thus ensures their correct alignment to the load.

Benefit 1  Stable magnet position when picking and lifting loads
 

Figure 1: Swing-free order picking from a cassette
 

The distance between the magnet groups can be adjusted to the corresponding material length, by moving the crane trolleys. As a result, beam length does not exceed   load length.

Benefit 2  Using a passive telescope short and long load  is transported safely (see also ‘Load deflection’.

The telescopic arms are guided by rollers. This results in low friction and smooth operation when moving the magnet groups.

Benefit 3  Accurate positioning and less wear

The passive telescope can also be operated inclined to lift short remnants using one magnet group only. This is advantageous e.g. on a saw, when long bars and short cuts must be transported with the same magnet system.

Benefit 4  Flexible material handling with optimum storage density
 

Figure 2: Lifting a short beam with a single magnet group
 

Criteria for choosing a passive telescope

Passive telescopes are a good choice when:

• material length ratio is 2:1 or more
• material is sufficiently rigid

• Crane is equipped with two independent trolleys
• The material is arranged in parallel to the crane bridge
   

Figure 3: Passive telescope with two magnet groups lifting a bundle of hollow sections

Multifunctional all-rounder

An active telescope is mounted to the crane on two points of suspension.  The distance between the magnets is varied by motor drive.

In contrast to the passive telescope, all magnets remain equidistant, which is particularly important for thin, flexible material (see also ‘Load deflection’).

Benefit 1  Variable magnet spacing results in low load deflection
 

Figure 1: Active telescope carrying a single plate
 

For an active telescope, the magnets are correctly distributed in length at the push of a button, which reduces material deflection and optimizes load distribution among the magnets. 

Many powerful magnets does not necessarily guarantee adequate lifting capacity; correct load distribution is at least as important for  safety.

Benefit 2  The load is equally distributed among magnets
 

Figure 2: Two active telescopes transporting long rebar bundles
 

The spreader beam should not be longer than the material to be lifted. This makes it easier to load and unload material in the vicinity of walls, uprights, warehouse bays, lorries, railway wagons or ships.

Benefit 3  Active telescope guarantees compact storage
 

Figure 3: Active telescope unloading rebar bundles from a ship

Criteria for choosing an active telescope

Active telescopes are a good solution when:

• the material varies considerably in length
• the material is highly flexible (e.g. rebars or sheet metal)

• Two crane suspensions are available
• the material is arranged parallel to the crane bridge
• or parallel to the crane runway
• the material must be rotated in both directions by slewing gear

An all-purpose design

When a crane offers two points of suspension for each trolley, a magnet system consisting of two individual spreader beams is ideal, a highly flexible, robust and cost-effective solution. The distance between the two independently controllable magnet groups can thus be adapted to different material lengths. There is not any intermediate beam structure between them.

Benefit 1  Simple design and efficient operation
 

Figure 1: Two individual spreader beams carrying a long beam
 

Short material and off-cuts can be lifted using one magnet group only. The length of the magnet beam never exceeds the length of the material to be lifted. This allows to  work near obstacles such as walls, uprights and warehouse bays as well as loading and unloading lorries and railway wagons.

Benefit 2  Compact design and high-density storage
 

Figure 2: Lifting pipe bundles out of uprights using two individual spreader beams  storage with two individual spreader beams
 

Lifting forces follow a direct line from magnets to crane ropes permitting a very lightweight spreader beam design featuring high ratio of lifting capacity per dead weight.

Benefit 3  Lightweight design and less wear
 

Figure 3: Two individual spreader beams lifting a long, thin plate
 

Usually two fixed beams are applied to keep costs low. However, the beams can also be fitted with travelling magnets (see figure 3) or from an active telescopes.

Correct positioning of the magnets on the load reduces load deflection significantly.

Criteria for choosing two individual spreader beams

Two individual spreader beams are a good solution when :

• The material to be handled
  • varies considerably in length
  • and is relatively rigid
• Two points of suspension are available for each trolley
• The material is arranged parallel to the crane bridge

Spreader beams for specific customer applications

In addition to the tried and tested standard spreader beam solutions, numerous specially designed TRUNINGER spreader beams can be found all over the world.

Tailored to specific customer request, new and inspiring solutions are engineered in close dialogue between customers and our specialists. We make your material flow fly, reliably, safe and no matter what the conditions are.

Should you envisage any unusual application for magnetic material handling, we would be delighted to take up discussion with you.

Example applications
 

Figure 1: A “full face magnet” with 175 ring magnets for loading and unloading a cutting machine
 

Figure 2: Fixed spreader beam for carrying plates with travelling magnets and removable extension arms; spreader beam is coupled to a container lifting device
 

Figure 3: “Full face magnet” for loading and unloading large-format plates in a single lift
 

Figure 4: Special spreader beam for carrying truck frame profile sets