Derailleur Spring Tension Adjustment Mechanism
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Solution Overview
Problem
Adjusting spring tension in bicycle derailleurs is challenging, especially at the inboard location, which is tight and difficult to access, requiring trial and error methods that are inefficient and inconvenient.
Innovation Solution
A mechanism featuring a rotatable orienting washer and coil spring with an adjusting device that allows for tension adjustment at the derailleur head without contacting the washer, using retaining arrangements like gear teeth, pawls, and ratchet teeth to secure the spring at desired positions, facilitating easier and more precise adjustments at the outboard side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adjustment is made at the inboard location of the derailleur head, then the spring tension can be adjusted, but the location is tight and difficult to access making the adjustment process complex and time-consuming
Solution Approach 1:
The patent relocates the spring tension adjustment mechanism from the inboard location to the outboard location of the derailleur head, effectively changing the spatial dimension of access. This allows users to adjust spring tension from the external side where there is ample space, rather than from the tight inboard location near the bicycle frame.
Solution Approach 2:
The patent introduces an intermediary mechanism consisting of a cup-shaped member with gear teeth that engages with a spring adjust collar. This intermediary allows the adjusting tool to rotate the spring adjust collar without directly contacting the orienting washer, mediating the adjustment process to achieve both ease of operation and precision.
2Productivity
If trial and error adjustment method is used at the derailleur cage, then spring tension can be varied, but the process requires multiple attempts and is inefficient
Solution Approach 1:
The patent incorporates a feedback mechanism where the cup-shaped member with gear teeth provides tactile and visual feedback during adjustment. The gear teeth engage with corresponding teeth on the spring adjust collar, allowing the user to feel and see the incremental changes in spring tension, enabling precise adjustment in a single attempt rather than through trial and error.
Solution Approach 2:
The patent allows the user to pre-determine the desired spring tension by rotating the spring adjust collar to a specific position before securing it. The retaining arrangement is designed to hold the collar at any angular position, enabling preliminary adjustment followed by secure locking, rather than requiring multiple trial attempts.
3Measurement precision
If the adjusting device contacts the orienting washer during adjustment, then the spring tension can be modified, but the precision and control of adjustment are reduced
Solution Approach 1:
The patent introduces a cup-shaped member with gear teeth as an intermediary between the adjusting tool and the spring adjust collar. This intermediary engages with matching gear teeth on the collar, providing precise mechanical coupling that allows controlled rotation without direct contact between the adjusting device and the orienting washer, thereby maintaining both precision and ease of operation.
Solution Approach 2:
The patent segments the adjustment mechanism into distinct functional components: the cup-shaped member with gear teeth for precise engagement, the spring adjust collar for tension control, and the retaining arrangement for securing the adjustment. This segmentation allows each component to perform its specific function optimally, with the gear teeth providing precise angular positioning.
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
Enables straightforward and precise adjustment of spring tension at the derailleur head, improving usability and reducing the complexity of the adjustment process by allowing for easy rotation and secure locking of the spring tension, enhancing the angular orientation control of the derailleur.
Implementation Method 1
A spring is provided in association with each of the pivot axes in order to balance the derailleur to achieve a correct angular position thereof
Implementation Method 2
An adjusting device rotates the second end of the coil spring relative to the other of the derailleur head and orienting washer, without contacting the orienting washer, to adjust tension of the coil spring
Data Source
AI summary
A mechanism for adjusting spring tension at a derailleur head mountable to a bicycle frame having a limiting stop, includes an orienting washer rotatably mounted to the bicycle frame and having a tail engaging the limiting stop. A coil spring has a first end fixed to the derailleur head and a second end rotatably mounted relative to the orienting washer. An adjusting sleeve in the head rotates the second end of the coil spring relative to the orienting washer, to adjust tension of the spring. A retaining arrangement releasably retains the second end of the spring at a desired angular position after the second end of the spring has been rotated. A bolt secures together the orienting washer, the spring, the sleeve and the retaining arrangement to assemble the mechanism and for mounting the assembled mechanism to the bicycle frame and the derailleur head.