Variable Clamp Linkage for Uniform Thermoforming Sheet Stretching

The clamp structure is made dynamically adjustable through the linkage mechanism connecting multiple clamps. The linkage allows the distance between clamps to be varied, transforming a static clamp system into a dynamic one that can adapt to different stretching requirements and achieve uniform stretching across the entire cover sheet area.

The clamp system is divided into multiple individual clamps connected by linkages rather than a single rigid clamp. This segmentation allows each clamp to be independently positioned and adjusted, enabling precise control over the stretching process and uniform distribution of force across the cover sheet perimeter.

The cover sheet is pre-stretched by the variable clamps before the final forming process. This preliminary stretching action, performed while the sheet is heated and pliable, prevents excessive expansion and sagging during subsequent processing, maintaining dimensional control and preventing wrinkles.

The variable clamps apply counteracting force to the natural expansion and sagging tendency of the heated cover sheet. By clamping and stretching the perimeter, the system creates a pre-tension that opposes the gravitational and thermal expansion forces, preventing defects before they occur.