Adjustable Bicycle Stem Assembly With Internal Cable Routing
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Solution Overview
Problem
Existing bicycle stems do not allow for adjustable length and height modifications, and they often expose cables externally, which is aesthetically unpleasing and cumbersome.
Innovation Solution
An adjustable stem assembly comprising a base, support, and optional separator, allowing for four distinct configurations that change the handlebar's height and length, with integrated cable passages within the stem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rotatable connection is used to adjust handlebar position, then the handlebar position can be modified along a circular trajectory, but the stem length cannot be modified and remains constant
Solution Approach 1:
The stem is divided into multiple modular components (first stem component, second stem component, optional third stem component) that can be independently selected and assembled. This segmentation allows the stem length to be modified by changing the combination of components, while the rotatable connection provides angular adjustment. The modular design resolves the contradiction by enabling both length variation and position adjustment through different assembly configurations.
Solution Approach 2:
The stem assembly incorporates a rotatable connection that allows dynamic adjustment of the handlebar position along a circular trajectory. Additionally, the modular components can be selectively assembled to dynamically change the stem length. This dynamic capability resolves the contradiction by providing both fixed length options (through component selection) and adjustable position options (through rotation).
2Ease of manufacture
If cables are routed externally for easy access, then cable installation is simple, but the appearance is aesthetically unpleasing and cumbersome
Solution Approach 1:
The stem components are designed with internal passages that nest the cables within the stem structure. The first, second, and optional third stem components contain hollow interiors through which cables can be routed internally rather than externally. This nesting approach resolves the contradiction by concealing cables within the stem's internal geometry, providing aesthetic appeal while maintaining cable accessibility through designated entry/exit points.
Solution Approach 2:
The stem components act as an intermediary structure that provides internal pathways for cable routing. Rather than allowing direct external cable placement, the stem's internal passages serve as a mediator that guides cables through the stem body. This resolves the contradiction by offering a compromise between external accessibility and internal concealment, with cables routed through the stem's interior while entering/exiting at convenient locations.
Data Source
Figure 1~2d
Figure 3~4b
Figure 5
AI summary
The invention discloses an adjustable stem assembly (1) for a bicycle comprising: a base (2) configured for fixation to the fork (H) of a bicycle (B); a support (3) configured for fixation to the base (2) alternatively in two positions and having a handlebar fixation means (32); a separator (4) for optional fixation between the base (2) and the support (3). Thus, the assembly (1) alternates between four configurations referred to respectively as short high, short low, long high and long low, where the height of the handlebar fixation means (32) is different in each of said four configurations. The invention also discloses a method for installing said stem assembly (1).