Aerodynamic Ski Pole Cross-Section Design
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Solution Overview
Problem
Modern ski poles face challenges in achieving high breaking strength, stiffness, and aerodynamic properties without increasing weight, as existing designs either compromise on weight or stability due to drag forces affecting their trajectory during skiing.
Innovation Solution
A ski pole with a cross-sectional shape featuring a first part with a curved portion and a second part connected by side parts, forming four corners, which gradually changes from a four-corner shape to a circular shape along the shaft, providing increased strength and aerodynamics without significant weight increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular cross-section shaft is used, then the ski pole has simple manufacturing and symmetric structure, but it produces drag and lift forces that cause trajectory deviation and require unnecessary corrective force
Solution Approach 1:
The patent applies asymmetry by changing the cross-sectional shape from circular to triangular. The triangular cross-section with one side facing forward eliminates the symmetric circular shape that generates lift and drag forces. This asymmetric geometry allows the pole to cut through air more efficiently without generating unwanted aerodynamic forces that would require corrective steering input from the skier.
Solution Approach 2:
The patent applies curvature by rounding the corners of the triangular cross-section. Instead of sharp 90-degree corners, the corners are rounded with a radius of curvature between 0.5-5mm. This curvature modification reduces turbulence and vortex formation at the corners while maintaining the beneficial asymmetric triangular shape, thereby reducing drag compared to sharp-cornered triangles.
2Weight of moving object
If the shaft diameter is reduced to decrease weight, then the ski pole becomes lighter, but the breaking strength and buckling resistance decrease
Solution Approach 1:
The patent applies composite materials by using fiber-reinforced plastic (FRP) construction with layers of carbon fiber, glass fiber, or other reinforcing fibers embedded in a polymer matrix. This composite structure provides high strength-to-weight ratio, allowing the shaft to maintain adequate diameter for strength while using lighter materials. The fiber orientation and layering can be optimized to provide maximum strength where needed while minimizing weight.
Solution Approach 2:
The patent applies parameter changes by modifying the cross-sectional geometry from circular to triangular with rounded corners. This geometric parameter change increases the section modulus and moment of inertia for a given area, thereby increasing bending strength and buckling resistance without increasing the overall size or weight of the shaft. The triangular shape with rounded corners provides more efficient material distribution.
3Object-affected harmful factors
If a triangular cross-section is used, then the ski pole has reduced drag and lower weight, but it may twist during use and has reduced stability
Solution Approach 1:
The patent applies asymmetry by orienting the triangular cross-section with one side facing forward in the direction of motion. This asymmetric orientation provides stable aerodynamic characteristics and prevents the pole from rotating during use. The asymmetric shape creates stable pressure distribution that resists twisting moments, thereby improving rotational stability while maintaining the drag-reducing benefits of the triangular form.
Solution Approach 2:
The patent applies curvature by rounding the corners of the triangular cross-section. The rounded corners with radius 0.5-5mm reduce stress concentration points that would otherwise be prone to failure and reduce turbulence. The curvature also helps stabilize the pole by creating more uniform airflow patterns around the corners, reducing vortex formation that could induce twisting moments.
4Strength
If the shaft wall thickness is increased to increase strength, then the breaking strength improves, but the weight increases
Solution Approach 1:
The patent applies composite materials by using high-strength fiber-reinforced plastics with optimized fiber content and orientation. The fiber layers (carbon, glass, or other reinforcements) provide exceptional tensile and compressive strength, allowing thinner wall sections to achieve the same strength as thicker solid sections. This enables weight reduction while maintaining adequate breaking strength through intelligent material selection and layering strategies.
Solution Approach 2:
The patent applies parameter changes by modifying the cross-sectional geometry to triangular with rounded corners, which increases the section modulus and moment of inertia. This geometric parameter change allows the shaft to achieve higher bending strength and buckling resistance with thinner walls compared to a circular section, thereby reducing weight while maintaining strength requirements.
Data Source
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AI summary
The invention is directed to a ski pole comprising a longitudinal shaft. The shaft includes a cross-section that comprises: -a first part including a curved first portion arranged symmetric about a cross- sectional centerline (CL) of the shaft, and -a second part including a second portion arranged symmetric about the cross- sectional centerline. Wherein the first part is connected to the second part by side parts including side portions, each side part comprises a first end connected to an end of the first part and a second end connected to an end of the second par, each connection between the side parts and the first and second parts forms a corner, such that there are total four corners in the cross-section of the shaft.