What Is a Pocket Spring Unit, and How Does It Work?

In the Turkish market this product answers to four names at once: paket yay, cep yay, torba yay and bağımsız yay. All four describe the same thing — a unit in which every coil is enclosed in its own fabric pocket and the pockets are joined to each other. There is no technical distinction between them; which name a supplier uses is mostly a habit of the factory or the region.

English adds its own list. Pocket spring, pocketed coil, encased coil and individually wrapped coil all name the same unit, German says Taschenfederkern, and French says ressorts ensachés.

The practical consequence is simple: a buyer comparing a quotation for paket yay against one for cep yay is comparing two words for one product. The real differences sit underneath the name, in the construction detail — wire gauge, pocket fabric, how the rows are joined, what happens at the edge, and how the unit is packed.

Production starts by winding the coils one at a time. Steel wire is formed into a helix at a set diameter and height, and those two figures — wire gauge and coil height — are the primary variables governing how far a given coil compresses under a given load. Change either and the firmness of the whole unit changes.

Each wound coil then goes into a pocket of non-woven fabric, and the pocket is closed. The fabric does more than hold the coil: it keeps metal from rubbing against metal, and metal from rubbing against the foam above. The pockets are not made singly but as a continuous strip of adjoining pockets, which produces a row of springs.

Rows are then laid side by side and joined. The join is usually made by ultrasonic welding or with adhesive, and the integrity of the finished unit largely rests on it — a weak join lets rows separate in service and the unit loses its shape.

In the final step the unit is brought to the required mattress size and, where specified, its perimeter is reinforced. Edge support may be a heavier wire in the outer rows or a foam frame built around the unit; both aim to delay the surface collapsing when weight sits on the edge.

In systems where the coils are tied to each other by helical wires, load at one point pulls the neighbouring coils down with it and the surface sinks across a wide area. A pocket unit has no such tie. Wherever the load falls, only the pockets under it compress, and the pockets beside them stay where they are.

The first thing this buys is localised response. The surface answers the heavy and the light parts of a body separately: shoulder and hip sink further while the lumbar region keeps being supported. As coil count rises the springs get thinner and sit closer together, so the contour is followed in smaller steps.

The second is reduced motion transfer. On a double mattress, movement on one side is not passed along to the neighbouring coils, so less of it is felt on the other side. There is no single number for this — it depends on the unit's construction, the layers above it and the size of the mattress.

Independence is not an advantage under every condition. A unit built from very few coils of heavy wire responds coarsely, and if the layers above are too firm the surface will not let the coils work separately in the first place. The unit is chosen together with what goes on top of it.

A pocket spring unit is not a mattress on its own; it is the mattress's load-bearing core. Layers sit above and below it, and the feel of the finished product comes out of how the unit and those layers behave together.

Directly above and below the unit there is usually a sheet of felt. Its job is threefold: it separates the coils from the soft layer above, it reduces the pocket fabric rubbing against foam, and it delays the coil ends making themselves felt at the surface over time. Above the felt comes foam as a comfort layer, while rebonded foam is more often used as a base or intermediate layer for support.

That is why the phrase “pocket spring mattress” names a combination of layers rather than a single product. The same unit gives a noticeably different mattress once the felt and foam above it change, so a quotation is worth reading for its layer list as much as for the unit specification.

We manufacture and supply the components of those layers; we do not make or sell finished mattresses. The pocket spring unit and the rebonded foam are our own production, while felt and roll foam are sourced and supplied. The party assembling the finished mattress is always the mattress manufacturer buying the components.

Most of the volume a pocket spring unit occupies is air: the inside of every coil and the space between them is empty. Roll-packing removes that emptiness temporarily — the unit is vacuum-compressed and wound into a roll.

For an exporter this converts directly into cost. Far more units fit into the same vehicle, so freight per unit falls, and over long distances that difference becomes a line of its own in the landed cost. Handling and warehouse space shrink with the volume too.

Compression has details of its own. How long a unit can stay rolled, and how much time it needs to recover its height once opened, are points to settle while the order is being discussed. Where they do not suit the buyer's process, the unit can equally be shipped uncompressed on a pallet.