Spreader types

Robust simplicity

Fixed spreader beams represent the simplest possible magnet beam design. Their main feature is the simple and robust form of construction. This style of spreader beam can often manage without any – or very few – moving parts, which underlines the simplicity of this type of solution.

Benefit 1: Low maintenance costs

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

With long spreader beams in particular it is possible to achieve a low dead weight by means of a honeycomb design (see figure 2).

Benefit 2: Low dead weight of the magnet gripper and less wear on the crane

Hooks for conventional material handling – for example, using chains and ropes – are possible at any place along the fixed spreader beam. The number and placement of hooks depends on the crane’s lifting capacity and on the structure of the beam. It is possible to attach 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 fitted with a quick-change system
 

A fixed spreader beam also permits the use of auxiliary functions. A number of optional auxiliary functions are available. These include, for example:

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

Figure 3: Fixed spreader beam with travelling magnet groups
 

In the right conditions fixed spreader beams provide a very economical solution.

Selection criteria for the fixed crosshead

Fixed spreader beams are a good solution for steel handling processes where the following conditions exist:

• The material to be handled is:
  • all of a uniform length, or
  • differs only slightly in length
  • and is sufficiently rigid
• Two crane suspension points are available for the spreader beam
• The material’s lengthways axis:
  • runs either parallel to the crane bridge
  • or parallel to the crane runway
• The material is to be slewed during transport using a rotating hoist

Driveless telescopic beam

A passive telescope is used on a crane equipped with two independent trolleys. A three-part telescopic beam connects the two sub-spreader beams and ensures proper alignment and stability of the magnet groups.

Benefit 1: Stabilised 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. Usually the overall beam length does not exceed that of the load.

Benefit 2: Using a passive telescope you can safely transport material of differing lengths (see also ‘Load deflection’).

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

Benefit 3: Accurate positioning and less wear

Positioning the passive telescope at a slight angle enables the operator to lift short material lengths using only one magnet group. This is advantageous, for example, when lifting material at sawing stations.

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 solution for steel handling processes where the following conditions exist:

• The material to be handled:
  • has an approximate length ratio of 2:1
  • is sufficiently rigid
• Two crane suspension points are available for the passive telescope
• The lengthways axis of the material runs 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 on two suspension points of a crane system. The spreader beam is fitted with a motor drive for varying the distance between the magnets.

In contrast to a passive telescope, all the magnets remain equidistant to one another, which is particularly important for non-rigid material (see also ‘Load deflection’).

Benefit 1: Adjustment of magnet spacing means only minor load deflection

Figure 1: Active telescope carrying a single plate

Simple control of the active telescope via an operator station enables the magnets to be positioned correctly on the load, thus reducing any load deflection and optimising the load distribution between the magnets. Having many powerful magnets does not necessarily guarantee adequate lifting capacity; good load distribution is one of the most important safety factors.

Benefit 2: Lifting capacity is spread equally across all magnets

Figure 2: Two active telescopes transporting long rebar bundles

The spreader beam is rarely longer than the material to be lifted. This makes it easier to load and unload material in the vicinity of obstacles such as 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 for steel handling processes where the following conditions exist:

• The material to be handled:
  • varies considerably in length
  • is relatively pliable (e.g. rebars or sheet metal)
• Two crane suspension points are available for the active telescope
• The material’s lengthways axis:
  • runs either parallel to the crane bridge
  • or parallel to the crane runway
• The material is to be slewed during transport using a rotating hoist or a loadslewing device

An all-purpose design

If a crane has two suspension points per trolley, then a magnet system with two individual spreader beams represents a particularly flexible, robust and inexpensive solution. One magnet spreader beam is reeved into each trolley. The distance between the two independently controllable magnet groups can thus be adapted to different material lengths. There is no connecting beam 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 just one magnet group. In this case the length of the magnet beam never exceeds the length of the material to be lifted. This makes it easier to work near to 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 crossheads

The almost direct line of force from the magnets onto the crane ropes permits a very lightweight spreader beam design with a good ratio of lifting power to dead weight.

Benefit 3: Lightweight design and less wear

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

The individual spreader beams are usually designed as low-cost fixed beams. However, they can also be fitted with travelling magnets (see figure 3) or used as active telescopes.

Simple operation by means of a control unit enables correct positioning of the magnets on the load, thus reducing any load deflection.

Criteria for choosing two individual spreader beams

Two individual spreader beams are a good solution for steel handling processes where the following conditions exist::

• The material to be handled
  • varies considerably in length
  • and is relatively rigid
• Two suspension points per trolley are available
• The material’s lengthways axis runs 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 are also in use around the world.

Tailored to specific applications, these special magnet beams support our customers’ steel handling processes with high reliability day after day and sometimes under extremely tough conditions. We develop and manufacture such systems in close consultation with the customer.

If you have an unusual application and are thinking about handling material magnetically, we would be delighted to discuss this with you.

Example applications

Figure 1: A “magnetic carpet” with 175 ring magnets for loading and unloading a cutting machine with plates of max. 12 x 3.5m

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

Figure 3: “Magnetic carpet” for loading and unloading large-format plates in a single lift
 

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