Bicycle Stem Locking Mechanism for Play Elimination
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Solution Overview
Problem
Existing bicycle handlebar stem systems face challenges in compact storage and anti-theft functionality due to play and clearance issues, leading to unsatisfactory handling and security concerns.
Innovation Solution
A stem design with integrated locking mechanisms that eliminate play through a combination of beveled locking components and elastomer rings, allowing for precise control and secure positioning of handlebars, compatible with both classic and ahead set assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If locking means are positioned close to the handlebar to eliminate play, then handling precision is improved, but manufacturing precision requirements increase significantly
Solution Approach 1:
The patent introduces a conical intermediary element that mediates between the locking means and the handlebar. This cone absorbs positioning tolerances through its geometry, allowing the locking mechanism to engage the handlebar securely without requiring extremely tight manufacturing tolerances. The conical shape provides a gradual transition zone that compensates for clearance variations while maintaining precise handling control.
2Volume of moving object
If handlebars are positioned coplanar with the frame for compact storage, then storage space is reduced, but the bicycle becomes unusable without mechanical modifications
Solution Approach 1:
The patent implements a dynamic locking system that allows the handlebar to be positioned in different configurations. The locking mechanism can secure the handlebar in a coplanar position with the frame for compact storage, while also allowing it to be returned to its operational position for normal use. This dynamic capability enables the system to adapt between storage and usage states without permanent mechanical modifications.
3Device complexity
If locking means are integrated completely into the stem, then device complexity is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the locking mechanism, the conical positioning element, and the handlebar interface into an integrated stem assembly. This consolidation reduces the number of separate components and simplifies the overall device structure. While the integration increases manufacturing complexity for the stem itself, it eliminates the need for separate locking devices and reduces assembly steps, ultimately simplifying the complete bicycle system.
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 compact storage option and enhanced security by eliminating play, ensuring precise handling and secure positioning of handlebars, thereby improving user safety and bike security.
Implementation Method 1
each receiving a key and a return spring arranged to return the key to the outside of its housing
Implementation Method 2
a bevelled core operated by a screw traction free mounted in said stem
Data Source
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AI summary
The invention relates to a stem (10) for a bicycle handlebar having controlled release of the steerability thereof, including a body (24) intended for receiving a stem arm (12) which in turn receives a handlebar, said stem also including a headset (40), a means (14) for attaching said stem (10) to the fork (16) of a bicycle including a head tube and a locking/unlocking means (18), characterised in that the locking/unlocking means (18) includes at least one key (56) placed in a cavity (54) arranged in the headset (40), a resilient means (58) for returning said at least one key towards the outside of said cavity, holes (36) arranged in the stem body (24) through which said keys pass, a ring (62) suitable for retracting the at least one key (56) through said holes (36) by a rotation or translation movement, respectively. The mounting also provides an aheadset arrangement.