Piezoelectric Drive Unit Layout for Reliable Runner Contact

The patent extracts the spring element from the system entirely, replacing it with a pretensioning device that applies force directly to the drive elements without requiring additional height. This eliminates the contradiction by removing the component that caused the height increase while maintaining contact reliability through direct mechanical pretensioning.

The patent replaces the spring-based mechanical system with a direct pretensioning mechanism that applies force more efficiently. This substitution allows for reliable contact during drive phase without the height penalty of spring elements, resolving the contradiction between reliability and compactness.

The patent implements dynamic control of the pretensioning force through the drive elements themselves. The actors can actively adjust their position and the force they exert on the element to be driven, allowing them to maintain reliable contact during drive phase while completely stroking off during return phase. This dynamic capability eliminates the harmful effects of excessive static spring forces.

The drive elements serve their own pretensioning function through their dimensional changes. By expanding and contracting, the actors automatically apply and release force on the element to be driven, eliminating the need for separate spring elements and enabling precise control of contact conditions without causing wear or reducing drive force.

The patent segments the drive function into multiple actors working in sequence rather than relying on a single miniaturized stroke section. This segmentation allows each actor to have larger, more manufacturable dimensions while achieving the same overall drive effect through coordinated action of multiple elements, reducing the impact of manufacturing tolerances.

The patent changes the operational parameters of the actors by implementing active pretensioning and controlled dimensional changes. This allows the system to operate with larger stroke movements that are less sensitive to manufacturing tolerances, while still achieving compact overall device dimensions through efficient force transmission and coordination of multiple actors.

The patent implements dynamic control of actor positioning through active pretensioning and controlled expansion/contraction. This allows compact actors to maintain precise contact during drive phases and complete separation during return phases, overcoming the limitations of their small height through active force management and coordinated motion control.

The system employs feedback control through the pretensioning mechanism and coordinated actuation of multiple actors. This ensures that even compact actors with limited stroke capability can maintain consistent contact and separation by continuously adjusting their position and force application based on the operational phase, resolving the contradiction between compactness and contact reliability.