Protective Case Coupling via Segmented Protrusions

The coupling unit is segmented into multiple functional elements: first protrusions extending from the detachable component, second protrusions extending from the component outer peripheral edge surface, and corresponding grooves in the casing body. This segmentation allows each element to perform a specific function, with the first protrusions providing initial engagement and the second protrusions with grooves providing enhanced stability, thereby resolving the contradiction between simple structure and reliable coupling.

The coupling mechanism transitions from a single-dimensional annular protrusion-groove interface to a multi-dimensional engagement system. The first and second protrusions extend in different directions and at different positions, creating engagement forces in multiple dimensions. This dimensional expansion increases the coupling stability without significantly complicating the manufacturing process, as each protrusion and groove can be formed using standard molding techniques.

The coupling unit is designed with dynamic characteristics that allow easy detachment when needed while maintaining stability during normal use. The first protrusions can be easily pushed out of the corresponding grooves to detach the back plate, providing ease of operation. Meanwhile, the second protrusions engaging with the grooves create a stable locked state during normal use, preventing accidental detachment. This dynamic design allows the same structure to provide both easy operation and reliable coupling.

The detachable coupling is segmented into two functional parts: first protrusions that enable easy detachment by being pushed out of grooves, and second protrusions that provide stable engagement during normal use. This segmentation allows the back plate to be easily installed and removed when needed, while maintaining coupling stability during normal operation, thus resolving the contradiction between ease of operation and reliability.