An innovative solution for carving Ski based on retractile blades

This paper presents the design of a new ski to improve the performances focusing especially on steering conditions. In the proposed solution an additional retractile edge has been added modifying the lower surface of the ski. It consists of a thin stainless steel plate suitably reinforced with two longitudinal ribs welded along the plate borders to create the blades. Then this element is constrained to the ski along the longitudinal symmetry axis. In unload and straight conditions the gap between the ski and the edge is null while in curves the retractile blade is deformed and pushed out by the force applied by the skier, penetrating the snow. The mechanism for the force transmission is based on two revolution joints, allowing small rotations of the boot with respect to the ski and compensating the ski deformation, and several pistons, pushing on the edge. Two ski prototypes have been manufactured, instrumented and tested on a snow track. In particular, in order to show the differences in terms of performance, the modified skis have been compared to the classic version. Additional considerations about the variations on stiffness and friction behavior introduced by the new solution have been drawn too.