Lifting cartons without carrying them: lifting aids and carton grippers.

A steel part has a fixed shape, a known weight and a centre of gravity that stays where it is. A carton has none of these for certain. Its contents may shift, its weight may vary from shipment to shipment, and its surface may be covered with film, labels or tape. And the board itself lets air through.

It follows that there is no carton gripper for everything. Which one fits depends on how the cartons are made, how they arrive and where they go.

The most common gripper for cartons is an area gripper that grips the lid from above. It is fast, because the operator only has to place it and lift. Two conditions have to be met, though: the lid has to carry the weight of the contents, and the vacuum generation has to compensate for the air flowing in through the board. Porous corrugated board therefore needs vacuum generation with considerably more flow than a smooth, sealed surface.

Separately switchable zones allow small and large formats to be gripped with the same gripper. Our guide on sizing vacuum lifters describes how holding force and reserve are calculated.

Open cartons, cartons with a weak lid or with heavy, loose contents are better gripped from the side or from below. A clamp gripper holds the carton on two opposite sides; a fork gripper moves underneath it. Both need space: a gap next to the carton or access to its underside, for example on a roller conveyor with a cut-out.

They are somewhat slower than a suction gripper, but independent of whatever is stuck to the surface. In practice the two principles are often combined: suction for the normal case, clamping or forks for the exceptions.

Where parcels of different sizes arrive – in parcel handling, returns, or goods-in with many suppliers – a parcel gripper has to adapt. That can be done with adjustable clamping jaws, suction zones or interchangeable grippers with quick couplings. An analysis of the formats shows which route is right: if a few sizes make up most of the volume, a gripper tailored to them pays off. With a very wide spread, adjustability matters more than the last bit of speed.

On a pallet, the pick height changes with every layer. The stroke of the lifting aid therefore has to reach from the bottom to the top layer, and the structure has to cover the whole pallet and the set-down point beside it. From conveyor to pallet, from rack to packing table: the path decides whether a jib crane is enough or a rail system is needed.

Our application “Moving eight hundred cartons per shift” shows what this looks like at a high-volume dispatch station. This page covers the selection in general; that one describes a specific case.

The design load is never the carton alone. An area gripper with vacuum generation, valves and handle has its own weight, which comes off the device’s rated capacity. Our Skyline rope balancers are rated for 60 and 100 kilograms including the tool; the I-GO lifting columns, depending on the model, for 60 to 400 kilograms. A balancer is often enough for cartons; where heavy containers or a heavy gripper are involved, the lifting column is the safe choice.