Chain Block Rolling Restriction for Dragging Stability

The patent applies preliminary anti-action by designing rolling restriction portions that prevent the chain block from rolling onto its side before dragging occurs. The rolling restriction portions create a physical barrier that stops the chain block from adopting a harmful orientation (wheel cover or gear case facing down) during the dragging operation, thereby preventing damage before it can occur.

The patent converts the potential harm of rolling during dragging into a benefit by using the rolling restriction portions to guide the chain block into a stable dragging posture. The rolling restriction portions transform the uncontrolled rolling motion into a controlled orientation where the chain block drags on its side surfaces, protecting the wheel cover and gear case from damage.

The rolling restriction portions provide preliminary anti-action by preventing the gear case from contacting the ground during dragging operations. By restricting rolling motion, the design ensures that the gear case maintains an elevated position, preventing direct contact with ground contaminants and eliminating the harmful effect of dust ingress through damaged rivets.

The patent converts the potential harm of ground contact into a benefit by using the rolling restriction portions to elevate the gear case during dragging. This transformation ensures that the gear case is protected from dust and contaminants while maintaining the mobility needed for operation.