Bicycle Compliant Seat Post Interface for Shock and Lateral Stiffness
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Solution Overview
Problem
Existing bicycles designed for paved roads face a challenge in reducing road shock transmission to the rider without increasing weight or compromising rear end lateral stiffness.
Innovation Solution
A bicycle frame with a movable seat post and a damping member that couples the seat post to the frame, allowing for shock absorption while maintaining rear end stiffness, using a hydraulic damper and a flared portion in the seat tube to facilitate flexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the rear end of the bicycle is made compliant to reduce shock transmission, then shock absorption is improved, but weight increases and rear end lateral stiffness is lost
Solution Approach 1:
A damping member (hydraulic or elastomeric) is introduced as an intermediary element between the seat post and frame. This mediator allows controlled movement to absorb shock while maintaining overall structural integrity and preventing excessive weight gain compared to full compliant rear ends
Solution Approach 2:
Compliance is localized specifically at the seat post interface rather than making the entire rear end compliant. The damping member is positioned only where needed to reduce shock transmission to the rider, while the rest of the rear triangle maintains its rigid structure for lateral stiffness
2Object-affected harmful factors
If the rear end of the bicycle is made compliant to reduce shock transmission, then shock absorption is improved, but rear end lateral stiffness is lost
Solution Approach 1:
The compliance is localized to vertical movement at the seat post interface through the damping member, while the rear triangle geometry and remaining structural elements maintain lateral stiffness. The damping member only allows movement in the vertical direction needed for shock absorption
Solution Approach 2:
The seat post system is segmented into a movable upper portion that can dampen vertical movement and a lower portion that remains rigidly secured to maintain lateral stability. This segmentation allows different parts to serve different functions
3Object-affected harmful factors
If a damping member is added to couple the seat post to the frame, then shock absorption is improved, but device complexity increases
Solution Approach 1:
A hydraulic damper is used within the seat post assembly to provide vibration damping. This compact hydraulic mechanism effectively reduces vibration transmission while occupying minimal space and adding relatively little complexity to the overall bicycle structure
Solution Approach 2:
The damping characteristics can be adjusted by changing parameters such as the size and position of the damping member, the securing location distance from the upper end, and the gap dimensions. These parameter adjustments allow optimization of shock absorption without fundamentally changing the design complexity
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
The solution effectively dampens movement of the seat post, absorbing shock and vibration, while maintaining lateral stability and reducing weight increase, allowing customization for rider preferences.
Implementation Method 1
The damping member (e.g., a hydraulic damper) couples the seat post to the frame to dampen movement of the upper portion of the seat post between the first and second positions
Implementation Method 2
the seat post flexes when the upper portion of the seat post moves from the first position to the second position
Data Source
AI summary
A bicycle comprises front and rear wheels, a frame, a seat post, and a damping member. An upper portion of the seat post is movable relative to the frame between a first position and a second position. The damping member couples the seat post to the frame to dampen movement of the upper portion of the seat post. The damping member can be positioned at least partially in a top tube of the frame. Preferably, the seat post flexes when the upper portion of the seat post moves. The frame further includes a securing location for securing the seat post, and the securing location is a distance from the upper end of the seat tube that is at least 30% of a length of a seat tube. The seat post has a front-to-rear width, and the seat tube has a rear wall spaced from the seat post by a gap that is at least 25% of a front-to-rear width of the seat post.