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Vertical towers: a thousand small parts in a few square metres of floor

A vertical tower solves the warehouse that has run out of floor but stores small goods: a thousand different stock keeping units (SKUs) in a few square metres, retrieved in seconds, with nobody walking an aisle or climbing a ladder. The goods travel to the window and the operator stays at the workstation. STOKA designs, imports, installs, integrates and supports these machines, and we always begin with the process. This page helps you see whether your warehouse is a candidate, and equally when it is not.

Tell us your problem

Where do I put a thousand small spare parts when the floor is full?

Upwards, inside a single closed cabinet. A vertical tower stacks trays as high as the roof allows and delivers the one you ask for at a window set at waist height. The same spare parts that today fill a whole aisle of shelving fit into a few square metres of floor.

What is a vertical lift module (VLM), and what is a carousel?

In plain terms: it is a tall closed cabinet full of trays with a window at operator height. You call up an item, the machine finds the tray it lives on and brings that tray to the window. Nobody walks to the shelf or climbs a ladder: the goods come to the person. The technical name for the tower format is vertical lift module (VLM): an extractor travels up and down the centre of the cabinet and moves trays between the storage columns and the delivery window. The carousel is the other family: instead of lifting individual trays, it rotates a closed train of bins until the one you want faces the operator, much like a dry cleaner. Both solve the same problem by different routes. STOKA designs them, imports them, installs them, integrates them with your management system and supports them.

The answer when you do not have 7 metres of height

Automated pallet systems work between 7 and 40 metres of height: below that floor the investment does not pay, because there is nowhere to put the height the system needs in order to perform. That describes an enormous number of urban warehouses, industrial mezzanines, workshops and older sheds with 4, 5 or 6 metres of clear height.

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The vertical tower has no such floor: it is dimensioned to whatever height exists. If you have 4 metres, the tower is 4 metres tall and still gives you back most of the floor that shelving occupies today, because inside it the trays sit tight against one another, with no aisles and no manoeuvring space. So when the survey shows low clear height and small goods, the conversation is not about stacker cranes: it is about towers. It works the other way round too: with 12 metres of clear height and pallets, the tower is not your system.

Where it pays off: small, valuable and many SKUs

The profile that performs best is always the same: small parts, many different SKUs and high value per unit. Machinery and automotive spares, workshop tooling, electronic components, medical supplies and consumables, laboratory samples, tooling inserts, and also document archives that must be kept on file but are almost never consulted.

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All of that usually lives today in long aisles of light shelving, where the operator walks, searches by eye, climbs a ladder and occasionally comes back with the wrong part. The tower reverses the whole arrangement: the operator stays at the window and the machine brings the correct tray over, with the exact position lit up on the tray itself. You gain floor surface, but above all you gain search time and accuracy. With locations managed by the software, inventory stops depending on the operator's memory.

Tower or carousel: what the survey looks at

The difference between the two families is the movement. The tower moves trays vertically inside a cabinet and exploits all the available height, so it performs better the higher the roof.

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The carousel rotates a closed train of bins; the horizontal type turns on the floor and the vertical type turns inside a lower cabinet, which suits premises with very low ceilings or where a tall structure cannot be anchored. Order rate is the other criterion: a tower delivers one tray at a time, whereas several units working in parallel, with the operator between them, sustain far more activity. The choice comes out of crossing real clear height, the number of SKUs, the size of the stored unit and order lines per hour at the peak, not at the average. We do that calculation during the survey, and the technical sheet for the chosen machine is delivered with the diagnosis.

What else you gain: lock and key, and goods that stay clean

Two advantages never make the brochure and yet weigh heavily in practice. The first is control: the machine closes under lock and key and access is managed per user, so what sits inside only comes out against a registered request with a name attached to it.

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For expensive spares, tooling that goes missing, medicines or controlled supplies, that is often worth as much as the square metre you save. The second is cleanliness: being a closed cabinet, the goods gather no dust and stay protected, which matters in electronics, in optics and in any sterile product. And the square metre you hand back to the floor has a price: premium industrial rent in the Buenos Aires Metropolitan Area (AMBA) averages USD 7.33 per square metre per month, and in the City of Buenos Aires (CABA) it rises to USD 14.52 (CBRE, Q2 2026). In a small urban warehouse, that arithmetic makes itself.

What determines the choice between a tower and a carousel?

We do not publish model-by-model specification tables: the detailed sheet comes with the assessment, sized against your operation. These are the criteria the choice is made on.

Real clear height
Measured to the lowest interfering point, not to the roof: a beam, a sprinkler, a light fitting. The tower is dimensioned to whatever you have, and below 7 metres it is usually the only automated option on the table.
Size and weight of what you store
The unit that goes on the tray has to be small and handled by hand. If you move pallets, reels or heavy packages, the system is a different one: the tower is not the answer, and it is worth knowing that before quoting.
Number of SKUs
The more different and the smaller the SKUs, the better it performs. With few SKUs and high volume each, the tower becomes expensive per position and the same money goes further in shelving or in a high-density system.
Order lines in the peak hour
One window serves one tray at a time. If the picking peak asks for more, the answer is several units in a battery or a different technology altogether. It is dimensioned on the measured peak, never on the monthly average.
Floor and access control
The machine concentrates a lot of load on very little surface, so permissible floor load is verified on site. And if you need traceability per user or a lock-and-key close, that is defined now, together with the management software.

Engineering for your operation

When is a vertical tower the wrong choice?

Our approach

It is the wrong choice in three scenarios, and all three are common. The first is bulky or heavy goods: if what you store is pallets, reels, profiles or packages a person cannot lift, the tray is not the right container and the correct system sits in another family. The second is holding few SKUs with high volume each: the tower charges dearly for every position, and with that profile the same money goes further in properly dimensioned shelving or in high density. The third is movement volume: if picking in the peak hour exceeds what a single window can deliver, the tower becomes the bottleneck of the entire operation, and adding units raises the cost until another technology turns out cheaper. And if the real problem is that inventory does not reconcile or that locations are disorganised, that is fixed first with process, not by buying a machine.

Frequently asked questions

Does it work if my warehouse is only 5 metres high?

Yes, and that is precisely its ground. Automated pallet systems need between 7 and 40 metres to perform, so below that height they drop out of the conversation. The vertical tower is dimensioned to the real clear height you have, measured to the lowest interfering point, and it still gives floor back.

How many trays does it hold, and how much weight per tray?

That depends on the model, on the available height and on the unit you store, so we do not publish a general table: out of context it leads to buying badly. The ranges are narrowed during the survey with your real dimensions and weights, and the full technical sheet for the chosen machine comes with the diagnosis.

Does it integrate with my management system?

Yes. The tower runs on its own software, which manages locations and directs the operator, and that software integrates with your warehouse management system or with the enterprise resource planning (ERP) system you already use. The integration is defined in the detailed design, because every installation has its own data map.

How long does installation take?

For automated systems the lead time is 3 to 4 months from the purchase order, and a tower usually lands at the short end of that range because it arrives pre-assembled and is anchored in place. The exact schedule is closed with the detailed design, depending on the civil works required.

Other systems

Tell us what you store and how much height you have

The survey establishes real clear height, unit size, the number of SKUs and the picking peak. With that we tell you whether the answer is a tower, a carousel or simply better organised shelving.