Parallel Linkage Handlebar Stem for Height Adjustment
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Solution Overview
Problem
Conventional handlebar stems for vehicles face challenges in adjusting height without altering the angle of the handlebars relative to the user's position, leading to complex adjustments and high wear due to non-positive connections under stress.
Innovation Solution
A height-adjustable handlebar stem with a multiple parallel linkage design, featuring pivot bearings with external shells and internal journals, and a spring-loaded fixation mechanism that allows for easy height adjustment without changing the handlebar's angle, distributing forces evenly across multiple connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a non-positive connection with separate locking pieces is used, then the handlebar stem can be adjusted in height, but the construction becomes unstable under high stress and experiences high wear on locking surfaces
Solution Approach 1:
The patent merges the locking function directly into the rod structure by forming L-shaped locking elements as integral parts of the rod ends, eliminating separate locking pieces. This integration ensures that locking forces are directly transmitted through the rod structure itself, providing stability under high stress while maintaining ease of adjustment through the lever mechanism.
Solution Approach 2:
The patent segments the locking mechanism into distinct L-shaped locking elements formed as integral parts of each rod, with separate bearing surfaces for locking and loading. This segmentation allows the locking function to be distributed across multiple rod pairs, reducing wear on any single surface while maintaining overall stability.
2Reliability
If additional separate locking pieces are provided, then the pivot bearing can be fixed, but the device complexity increases
Solution Approach 1:
The patent combines the locking function with the rod structure by forming L-shaped locking elements as integral parts of the rod ends. These locking elements are seamlessly integrated into the rod geometry, eliminating the need for separate locking pieces while maintaining fixation stability through the form-fit connection with the bearing shells.
Solution Approach 2:
The rod structure serves multiple functions simultaneously: it provides the structural connection, contains integral L-shaped locking elements for fixation, and forms pivot bearings for rotation. This multi-functionality eliminates the need for separate locking pieces and reduces overall device complexity while maintaining reliability.
3Adaptability or versatility
If the handlebar height is adjusted by axial shifting within the steerer tube, then continuous height adjustment is possible, but the rotational orientation changes during adjustment
Solution Approach 1:
The patent employs a dynamic parallel linkage mechanism where four rods are arranged in two pairs, with each pair forming a parallelogram. This dynamic structure allows the handlebar to adjust height continuously while maintaining a constant angle relative to the steerer tube, as the parallel rods ensure that the handlebar remains parallel to its original orientation throughout the adjustment range.
Solution Approach 2:
The patent transitions from simple axial shifting (one-dimensional adjustment) to a parallel linkage mechanism that operates in multiple dimensions. The four rods are arranged in three-dimensional space with specific orientations, allowing height adjustment while constraining rotational movement through the geometric constraints of the parallel linkage structure.
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 provides a stable, easy-to-adjust handlebar stem that maintains the handlebar's angle relative to the user, reducing wear and complexity by distributing forces and eliminating the need for separate locking pieces, allowing for efficient height adjustment without unintended movements.
Implementation Method 1
the bearing journals designed to be axially displaceable against a spring load
Data Source
AI summary
In order to enable the height of the steering on vehicles with handlebars to be adjusted without the angle of attack being altered at the same time, the connection between steer tube and handlebar is designed as multiple parallel rods with at least two rod pairs (6, 6" and 6', 6'") arranged one on top of the other. The rods are arranged laterally on the steer tube (2) and rotatably mounted at the ends. The rotary bearings are formed by outer bearing shells (7 to 7) and inner bearing journals (8 to 8), the bearing shells being designed either as cylindrical openings in the rods (6, 6" and 6', 6'") or as separate shells connected to the rods. The rotary bearings are detachably fixed to one or both end(s) of at least two rod pairs by designing the bearing journals to be axially movable against a sprung load and guiding said bearing journals through the bearing shells. The outer ends of the bearing journals are designed as a pan head (9, 9' and 9", 9"') with a toothing ring directed axially inwards and the corresponding bearing shells with corresponding toothing directed axially outwards. On both sides of the steer tube (2), at least two pan heads (9, 9' and 9", 9"') arranged one above the other are firmly connected to one another.