Preloaded Torsion Spring for Robotic Surgical Grip Force Control

The patent employs a variable mechanical advantage mechanism where the mechanical advantage ratio changes during the clamping cycle. Initially, a high mechanical advantage provides sufficient clamping force to overcome tissue stiffness, then transitions to a lower mechanical advantage to prevent excessive force and tissue damage. This dynamic parameter change resolves the contradiction between needing high force and avoiding tissue damage.

The mechanism transitions from a static high mechanical advantage design to a dynamic system where the mechanical advantage varies continuously during operation. The mechanism automatically adjusts its force multiplication ratio based on the clamping state, providing high force when needed and reducing force when tissue is securely held, thereby preventing damage while maintaining effective manipulation.

By changing the mechanical advantage parameter dynamically during the clamping cycle, the system achieves both high force generation and precise force control. The variable ratio allows the mechanism to adapt its stiffness characteristics, providing high force when needed while maintaining controllability throughout the operation.

The dynamic adjustment of mechanical advantage transforms a stiff, hard-to-control mechanism into an adaptable system that can precisely control applied force. The mechanism's stiffness varies during operation, being high when force is needed to initiate clamping and lower when precise force control is required to maintain the clamp without damaging tissue.