Back-Injected Fiber-Reinforced Ski Boot Shell
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Solution Overview
Problem
Existing methods for producing fiber-reinforced ski boot shells are complex and costly, requiring separate preforming steps and multiple injection molding processes, as well as the additional step of gluing on an elastomeric sole.
Innovation Solution
A method involving back-injection of a plastic material into a two-dimensional, sheet-like fiber structure within an injection mold, allowing for simultaneous three-dimensional shaping and forming of the shell element in a single step, using a thermoformable plastic material and fiber composite, which maintains the shell's geometry and provides direction-dependent elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate preforming steps and multiple injection molding processes are used to produce fiber-reinforced ski boot shells, then the structural integrity and reinforcement are improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple manufacturing steps into a single injection molding process. The fiber reinforcement elements are integrated directly into the shell molding process, eliminating separate preforming and assembly steps. The injection mold includes a recess for receiving the fiber reinforcement element, and plastic material is injected to surround and bond with the fiber element, creating an integrated fiber-reinforced shell in one operation.
2Strength
If separate preforming steps and multiple injection molding processes are used, then the fiber reinforcement is effectively achieved, but the production time and cost increase
Solution Approach 1:
The patent merges the fiber reinforcement integration step with the main shell injection molding process. The fiber reinforcement element is placed in the mold recess, and the plastic material is injected in a single continuous operation, eliminating multiple separate processes and reducing production time while maintaining effective fiber reinforcement.
3Ease of manufacture
If a two-dimensional fiber structure is directly back-injected with plastic material, then the manufacturing process is simplified, but the bond strength between plastic and fiber may be insufficient
Solution Approach 1:
The patent utilizes thermal parameters to enhance bond strength. The mold and fiber reinforcement element are heated to a temperature close to the melting point of the plastic material before injection. This temperature control ensures optimal bonding between the plastic and fiber structures during the injection process, achieving strong adhesion while maintaining manufacturing simplicity.
4Adaptability or versatility
If the shell-shaped element is made thermoformable between 50°C and 130°C, then the adaptability and customizable fit are improved, but the structural stability may be reduced
Solution Approach 1:
The patent applies fiber reinforcement elements specifically in zones where structural stability is critical, while allowing other areas to remain thermoformable for adaptability. The fiber reinforcement provides directional stiffness and maintains shell geometry in key areas during the thermoforming process, enabling the shell to be heated and molded to the user's foot while preventing excessive deformation and maintaining structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies the production process, reduces costs, and achieves a strong, intimate connection between the plastic and fiber structures, maintaining the shell's geometry and providing enhanced rigidity and adaptability for a comfortable, customizable fit.
Implementation Method 1
the planar fiber structure is first placed in an injection mold and then the liquid plastic material is injected onto the fiber structure
Implementation Method 2
The plastic material of the shell-shaped element and the fiber structure are thermoformable between 50°C and 130°C
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a shoe (1), in particular a ski boot, and to a method for producing a shoe (1), having a shell-shaped element (2, 3), which consists at least partially of a plastic material, wherein the shell-shaped element (2, 3) has at least one section (7) in which reinforcing fibers are provided and the reinforcing fibers are combined in a flexible, film-like, substantially flat fiber structure (6) before the shell-shaped element (2, 3) is formed, wherein the film-like fiber structure (6) is back-molded with the plastic material in order to form a three-dimensionally shaped shell-shaped element (2, 3) that is fiber-reinforced in some segments.