Spreader Adjustment Mechanism Foot Pedal Operation

The patent introduces a foot pedal positioned at a lower level than the handle, allowing the user to operate the adjustment mechanism using their foot instead of their hand. This spatial repositioning from hand level to foot level eliminates the need to repeatedly bend down, transforming a labor-intensive hand operation into an ergonomic foot operation that maintains productivity while improving ease of operation.

The patent extracts and eliminates the complex Bowden cable and biasing means system from the adjustment mechanism. Instead, it uses a simple spring-loaded stopper that engages with a rack on the adjustment element. This simplified mechanism achieves the automatic closing function through a direct mechanical connection rather than through complex cables and biasing components, significantly reducing manufacturing and maintenance costs while preserving the adaptability of automatic hole closing.

The patent implements a self-service mechanism where the spring-loaded stopper automatically engages and disengages from the rack on the adjustment element based on its position. As the adjustment element moves during operation, the rack teeth naturally interact with the stopper, causing it to self-lock at predetermined positions without requiring additional actuators or complex control systems. This self-service approach provides reliable mechanical stability while minimizing device complexity.