Ski Boot Last with Sliding Insert and Conical Pins
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Solution Overview
Problem
The existing methods for manufacturing ski boot shells with rigid soles face complications during unseating from molds, leading to misalignment, deformation, and costly production discards, compromising safety and increasing production costs.
Innovation Solution
A last for boot shell production with a slideable insert and bevel-free pins that allow for inclined sliding, facilitating easy and precise unseating without deformation, ensuring correct alignment and reducing production waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bevel-free pins are used to maintain mechanical grip and positioning precision, then fixing reliability is improved, but unseating difficulty increases due to mechanical interference with the metal plate seat
Solution Approach 1:
The pin is divided into two functional segments: a cylindrical body for positioning and mechanical grip, and a conical tip for unseating. This segmentation allows each part to perform its specific function optimally - the cylindrical portion maintains fixing reliability while the conical portion enables easy unseating by reducing friction during extraction
Solution Approach 2:
The pin geometry is modified by adding a conical tip that changes the contact parameters during unseating. The conical shape alters the friction characteristics and contact area as the pin exits the metal plate seat, transforming the unseating process from difficult to easy while maintaining the cylindrical body's positioning function
2Manufacturing precision
If the last is extracted at normal angle to maintain shell integrity, then shell deformation is minimized, but unseating time increases due to friction between centering elements and metal plate seat
Solution Approach 1:
The pin tip geometry is changed to a conical shape that modifies the extraction parameters. During unseating, the conical tip reduces contact friction with the metal plate seat, enabling faster extraction. The main extraction angle remains normal to preserve shell integrity, while the conical tip facilitates smoother removal
3Ease of operation
If beveling is applied to centering pins to facilitate disengagement, then unseating ease is improved, but positioning precision deteriorates leading to misalignment
Solution Approach 1:
The pin is segmented into a cylindrical body for precise positioning and a separate conical tip for easy unseating. The cylindrical body maintains full contact with the metal plate seat during positioning, ensuring precision, while the conical tip at the end facilitates disengagement without compromising the positioning function of the main pin body
Solution Approach 2:
Different portions of the pin have different geometric qualities - the cylindrical body provides uniform contact for precise positioning, while the conical tip provides reduced friction for easy unseating. This local differentiation of geometric properties allows both positioning precision and unseating ease to coexist
4Strength
If rigid materials are overmolded on the last to produce ski boot shells, then shell strength is improved, but production time increases and deformation risk increases during unseating
Solution Approach 1:
The pin tip geometry is changed to conical, which modifies the extraction parameters for rigid materials. The conical shape reduces contact friction and stress concentration during unseating, enabling faster removal of rigid shells without causing deformation or damage, thus improving productivity while maintaining shell strength
Data Source
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AI summary
A last (1, 101) for obtaining a shell (2) of a boot provided with a rigid sole (3) and, in the toe region (4), at least one metal plate (5a, 5b); the last (1, 101) comprises a main body (9) with which an insert (11, 111) is slideably associated, at the toe region (4), and can slide with respect to the main body (9) along a plane that is inclined by a different angle to the normal angle of extraction of the last (1, 101) from the shell (2); at least two bevel-free first pins (17a, 17b) protrude downward from the insert (11, 111) and interact selectively with the at least one metal plate (5a, 5b).