KELLY’s engineering architecture originates from an absolute compromise between heavy-duty loads and clean environments. Addressing the mobility requirements of medical carts and professional instruments, we abandoned visual lightness in favor of a fully enclosed PA bracket structure, physically cutting off all paths for environmental debris to infiltrate the wheel core. This almost cold, closed-skeleton design firmly locks high-precision ball bearings within. To master an extreme load capacity of up to 120kg, workshop technicians performed rigorous stress calibrations on the TPU overmolding thickness and twin-brake components. Forgoing all redundant design language, it relies solely on the strictest physical barriers to deliver the uncompromising silence and smoothness required in a late-night hospital ward.