Samsung Patents a Hollow-Shaft Hinge Assembly for Foldable Devices

By Patentlyze Team · Updated May 15, 2026

Samsung is patenting yet another hinge design — this time built around a hollow shaft with an inner rotating shaft connected to an outer bracket via link members. It's the kind of incremental mechanical engineering that quietly makes or breaks foldable phones.

What Samsung's hollow-shaft hinge actually does

Imagine folding your phone in half a thousand times a day. The hinge holding those two halves together has to be precise, durable, and thin — all at once. That's a genuinely hard engineering problem, and Samsung has been iterating on hinge designs for years across its Galaxy Z Fold and Flip lines.

This patent describes a hinge where a fixed outer hollow shaft stays anchored to the device's frame, while an inner shaft rotates inside it. A bracket wraps around the outside of the hollow shaft and is physically linked to that inner shaft through one or more connector pieces called link members. When you fold the device, the inner shaft and outer bracket rotate together as a single unit relative to the fixed hollow shaft.

The clever part is that the link member synchronizes the inner and outer rotating components without them being directly attached to each other — the hollow shaft sits between them as a kind of structural intermediary. It's a compact way to distribute rotational forces across more parts, which can reduce wear and improve feel.

How the shaft, bracket, and link members connect

The patent describes a hinge assembly with four main components working in concert:

• Fixing member / hollow shaft: This is the static anchor — a tube-shaped shaft that stays fixed relative to the device body and defines the hinge axis.
• Inner shaft: Sits inside the hollow shaft and rotates around the same hinge axis. It's the active rotating core.
• Bracket: Wraps around the outside of the hollow shaft and also rotates around the hinge axis — so both the inner shaft and the bracket rotate, but the hollow shaft between them stays still.
• Link member(s): One end attaches to the inner shaft; the other end is fixed to the bracket. This mechanical link forces the inner shaft and bracket to rotate together, even though they aren't directly connected.

The key insight is that sandwiching the fixed hollow shaft between two co-rotating components — one inside, one outside — allows the hinge to maintain structural rigidity while still enabling smooth rotation. The link member acts like a mechanical coupler, transferring rotational motion from the inner shaft outward to the bracket without requiring a direct rigid connection between them.

This architecture could allow for tighter tolerances and more consistent torque feel across the fold arc, which matters for premium foldable devices.

What this means for future Samsung foldables

Hinge reliability is arguably the most important engineering challenge in foldable phones. A hinge that feels loose after six months, or one that develops a gap or wobble, is a product-review killer. Samsung's Galaxy Z Fold and Flip series have steadily improved hinge feel over generations, and patents like this one show the incremental mechanical work behind those improvements.

For you as a user, better hinge engineering translates directly to a phone that folds and unfolds with consistent resistance, stays flat when open, and doesn't creak or flex where it shouldn't. This particular design — with its hollow-shaft sandwich architecture — seems aimed at distributing stress more evenly, which could mean longer hinge lifespan and a more premium tactile experience on future Galaxy Z devices.

Editorial commentary on a publicly published patent application. Not legal advice.