Haymaking Machine Coupling Return Device Bidirectional Energy Control

The invention inverts the traditional return device by adding a second deformable element that acts in opposition to the first element. While the first element (buffer) only resists upward movement, the second element (spring) only resists downward movement. This bidirectional resistance system controls vertical movements in both directions, eliminating the instability and uncontrolled motions that occur with unidirectional return devices when operating over uneven terrain.

The return device is segmented into two distinct functional elements: a first deformable element (buffer) that compresses during upward pivoting to control upward travel, and a second deformable element (spring) that compresses during downward pivoting to limit downward movement. This segmentation allows each element to specialize in one direction of movement, effectively absorbing shocks and jolts in both directions while maintaining a relatively simple overall structure.

The coupling device maintains its adaptability through the dynamic interaction of two deformable elements with different characteristics. The buffer provides progressive resistance during upward movement while the spring provides resistance during downward movement. This dynamic system allows the coupling to adapt to varying terrain conditions while simultaneously controlling the vertical position of the trunnion, ensuring consistent working height for the raking forks regardless of ground unevenness.