The design enables the lifting loops to be attached around the hooks on the outside of the 4 poles. When filling an empty big bag, this hook will create tension on the lifting loops (starting low, and ending up at the top), while the big bag is lowered on the bottom deck (pulling on the springs).

• Advantages: compared to the lockhead version, as explained above, the spring will be able to lift the last 100-200kg (depending on the material) from the big bag when emptying.

• Disadvantages: taking out a full big bag, when there is tension on the spring, is very difficult.