This hinge is a key element in the new form factor.
A two-part material is published on the company’s website that shed light on the most interesting design feature of the Galaxy Z Flip smartphone – the folding mechanism, which is a key element of the new form factor. It allows not only to open and close the screen, but also to fix it at different angles.
The designers had the task of creating a compact and reliable hinge, and to protect the thinnest gap between the hinge and the screen from small particles.
The hinge device is shown in the first three illustrations. The mechanism consists of two cone-shaped cams with a flat top at both ends of the hinge and spring.
The spring presses on the cams, providing a reliable fixation of the device when folded.
When the device opens, the upper cam begins to slip. At 90 °, the cams are in contact with the flat part of the surfaces, and when fully open (180 °), the upper cam is on the other side of the slope. In this case, the spring creates tension, fixing the hinge in this position.
As for the protection against the penetration of dust and other particles, it is provided by brushes made of nylon fibres, which “wipe” the surface of the outer part of the hinge when folding and unfolding.
This solution allows to ensure the durability of the structure and does not depend on small changes in the size of the gap during folding. By the way, with regard to durability, the hinge is tested for 200,000 operations. This part of the construction is shown in the bottom illustration.