Bicycle Seat Post Four-Bar Linkage Position Changer
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Solution Overview
Problem
Cyclists face challenges in quickly and easily switching between aerodynamic and upright riding positions on road bicycles due to limited adjustment capabilities of traditional seat posts, which can lead to discomfort and inefficiency when changing riding styles during a ride.
Innovation Solution
A bi-stable dual position changer using a four-bar linkage mechanism allows for rapid and reliable alternation between two seat positions, maintaining consistent seat-to-bottom-bracket length, without the need for tools or replacement of the seat post, enabling seamless transitions between aerodynamic and upright riding positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional seat post is used with limited adjustment range, then the structure remains simple and reliable, but the rider cannot achieve both aerodynamic and upright positions effectively
Solution Approach 1:
The seat post incorporates a four-bar linkage mechanism with movable links that enable dynamic repositioning of the saddle between two distinct positions (aerodynamic and upright). The mechanism includes a first link, second link, third link, and fourth link connected through pivot points, allowing the saddle to transition from a first position suitable for aerodynamic riding to a second position suitable for upright riding, thereby providing adaptability without requiring multiple separate seat posts.
Solution Approach 2:
The seat post system is divided into multiple independent links (first link, second link, third link, fourth link) that can move relative to each other. Each link serves a specific function in the mechanism, with the first link connected to the saddle, the second link connected to the first link, the third link connected to the second link, and the fourth link connected to the third link and the seat tube. This segmentation allows for controlled movement between positions while maintaining structural integrity.
2Adaptability or versatility
If the saddle position is adjusted significantly forward for aerodynamic riding, then aerodynamic efficiency improves, but the seat cannot be moved back to a suitable position for upright road riding without reinstalling the seat post
Solution Approach 1:
The mechanism enables rapid transition between saddle positions through the coordinated movement of the four-bar linkage. The rider can switch between the first saddle position (forward for aerodynamic riding) and the second saddle position (rearmored for upright riding) by actuating the mechanism, eliminating the need to remove and reinstall the seat post. This dynamic repositioning capability addresses both the need for extended adjustment range and the time loss associated with repositioning.
3Ease of operation
If seat angle adjustment is performed using traditional bolt manipulation, then the seat angle can be changed, but the rider must get off the bicycle to perform adjustments
Solution Approach 1:
The mechanism is designed to be actuated by the rider during normal riding without requiring dismounting or tool use. The fourth link is connected to the seat tube and can be manipulated by the rider to trigger the position change, allowing the seat angle to be adjusted on-the-fly. This self-service capability enables the rider to perform adjustments independently while maintaining control of the bicycle.
4Adaptability or versatility
If clip-on aero bar extensions are used to achieve aerodynamic position, then aerodynamic shape improves, but the rider is in an uncomfortably stretched out position due to limited forward travel adjustment of the typical seat
Solution Approach 1:
The four-bar linkage mechanism provides controlled forward travel of the saddle to the first position, which is optimized for aerodynamic riding with aero bars. The mechanism ensures that the saddle moves to a precise forward position that maintains proper rider geometry, preventing the uncomfortably stretched position that occurs with limited adjustment seats. The dynamic repositioning capability allows the rider to achieve the aerodynamic position comfortably and maintain it during riding.
Data Source
AI summary
A bicycle seat position changer is provided which allows the rider to quickly change the effective seat tube angle of the bicycle without requiring the use of tools. The seat position changer allows the rider to move the seat between a forward position and a rearward position, allowing a rider to select a more aerodynamic position or a traditional road position while riding, as required for comfort or by riding conditions. The seat position changer allows the rider to adjust the seat position between the forward and rearward positions while maintaining a consistent difference in seat-to-bottom-bracket length. In one embodiment the consistent difference in seat-to-bottom-bracket length is close to zero and imperceptible to the rider.