Bicycle Shift Lever Ratchet Layout for Compact Robust Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing operating devices for human-powered vehicles, such as bicycles, are costly and lack robustness while requiring complex constructions that hinder compact design.
Innovation Solution
The operating device incorporates a support structure with pivotally supported first and second pawls on a user operating member, biased for quick engagement and disengagement, and a ratchet mechanism with a positioning pawl for precise control, allowing for reduced manufacturing costs and enhanced robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex construction is used in the operating device, then the robustness is improved, but the manufacturing cost increases and the device size increases
Solution Approach 1:
The first pawl and second pawl are pivotally supported on the same first user operating member, merging multiple functions into a single component. This reduces the overall number of parts and simplifies the construction while maintaining robustness through the coordinated action of the two pawls with different pivot axes
Solution Approach 2:
The first user operating member serves multiple functions: it supports both the first pawl for releasing the positioning pawl and the second pawl for pulling the ratchet member. This multi-functional design reduces component count and simplifies the overall construction while maintaining reliable operation
2Ease of manufacture
If the first pawl and second pawl are pivotally supported on the first user operating member, then the manufacturing cost is reduced, but the robustness may be compromised
Solution Approach 1:
The first pawl and second pawl are positioned at different pivot axes that are offset from each other on the first user operating member. This asymmetric arrangement allows each pawl to independently perform its function with optimal mechanical advantage, ensuring robust operation while using a single operating member
Solution Approach 2:
The first user operating member is segmented into two distinct functional zones: one for the first pawl that releases the positioning pawl, and another for the second pawl that pulls the ratchet member. This segmentation allows independent optimization of each function while reducing overall manufacturing cost through component consolidation
Data Source
AI summary
An operating device includes a support structure, a ratchet member, a positioning member, a release member, a first user operating member, a first pawl and a second pawl. The ratchet member is movable between a plurality of predetermined positions. The positioning member includes a positioning pawl that selectively engages the ratchet member to selectively establish the predetermined positions. The release member is movable between a first position and a second position to disengage the positioning pawl from the ratchet member so the ratchet member can move in a releasing direction. The first pawl and the second pawl are pivotally supported on the first user operating member around different pivot axes. The first pawl moves the release member from the first position to the second position during operation of the first user operating member. The second pawl moves the ratchet member in a pulling direction.