Dropper Post Pivot Geometry for Consistent Saddle Position
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Solution Overview
Problem
Dropper seat posts on modern off-road bicycles often compromise pedaling efficiency and rider comfort due to fixed seat tube angles that do not accommodate the biomechanical needs of riders across varying seat heights, leading to sub-optimal saddle positions and potential knee pain or injury.
Innovation Solution
A positionally optimized saddle dropper post system with a tension bar and pivot assemblies that allow the seat post to pivot, maintaining a consistent rider position and seat tube angle across different heights, ensuring optimal knee alignment and weight distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dropper seat post extends along a single axis of reciprocation, then the structure is simple and easy to manufacture, but the effective seat tube angle decreases and saddle pitch remains constant, leading to sub-optimal pedaling efficiency and knee positioning
Solution Approach 1:
The patent applies dynamics by making the seat tube angle adjustable rather than fixed. The dropper post mechanism allows the seat tube angle to change dynamically based on the extension position, with the angle being steeper when extended and shallower when compressed. This dynamic adjustment optimizes pedaling efficiency at different saddle heights while maintaining a relatively simple telescoping structure.
Solution Approach 2:
The patent changes the geometric parameter of the seat tube angle dynamically. Instead of maintaining a constant seat tube angle, the design allows the angle to vary as the dropper post extends or compresses. This parameter change ensures that the rider's knee remains properly positioned relative to the pedal spindle throughout the range of motion, thereby improving pedaling efficiency without requiring a completely complex mechanism.
2Ease of operation
If the seat post is extended to support rider weight during climbing, then the saddle is positioned further from the bottom bracket for fuller leg extension, but the knee position relative to the pedal becomes non-perpendicular, increasing risk of knee pain and injury
Solution Approach 1:
The patent uses dynamics to adjust the seat tube angle based on the dropper post extension position. When the post is extended for climbing, the seat tube angle becomes steeper, which positions the rider's knee correctly relative to the pedal spindle. This dynamic adjustment ensures that even when the saddle is further from the bottom bracket, the knee remains properly aligned, preventing harmful oblique forces during pedaling.
Solution Approach 2:
The patent changes the seat tube angle parameter in response to dropper post extension. By increasing the seat tube angle when extended and decreasing it when compressed, the design maintains optimal knee-pedal geometry throughout the full range of motion. This parameter adjustment eliminates the harmful effect of non-perpendicular knee positioning that would otherwise occur during extended positions.
3Adaptability or versatility
If the seat post is compressed closer to the top tube for descents, then the rider can move weight more freely, but the effective seat tube angle decreases further, compromising pedaling efficiency when not fully extended
Solution Approach 1:
The patent applies dynamics by making the seat tube angle responsive to the dropper post position. When compressed for descents, the seat tube angle becomes shallower, allowing the rider to move weight freely. When extended for climbing, the angle steepens to optimize pedaling efficiency. This dynamic adaptation ensures that pedaling efficiency is maintained at intermediate positions rather than being compromised by the compressed configuration.
Solution Approach 2:
The patent changes the seat tube angle parameter dynamically based on dropper post extension. The angle is steeper when extended (improving pedaling efficiency) and shallower when compressed (improving terrain adaptability). This parameter variation ensures that the bicycle maintains optimal performance characteristics across different riding conditions and intermediate positions, rather than sacrificing pedaling efficiency when not fully extended.
Data Source
AI summary
A bicycle frame includes a front triangle comprising a head tube and a bottom bracket shell, a tension bar comprising a first end and a second end, wherein the first end of the tension bar is pivotably connected to an upper portion of a telescoping seat post assembly, and a first fore pivot assembly at a first reach point. The first reach point is between a reach point of the bottom bracket shell and a reach point of the head tube. The first fore pivot assembly is pivotably connected to the second end of the tension bar. The frame further includes an aft pivot assembly at a second reach point, wherein the second reach point is closer to the reach point of the bottom bracket shell than the first reach point, and wherein the aft pivot assembly is pivotably connected to a lower portion of the telescoping seat post assembly.