Bicycle Shifter Pawl Segmentation for Shock Reduction
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Solution Overview
Problem
The existing bicycle operating devices, particularly those with a position maintaining pawl, often experience a rough releasing action due to potential shocks between the release member and the pawl, which can hinder smooth operation.
Innovation Solution
The bicycle operating device incorporates a support structure with a release member, a positioning ratchet, and a position maintaining pawl, featuring a first and second pawl part that rotate together and independently around pivot axes, reducing shock during the release operation by adjusting the contact and holding portions to ensure a smooth release mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a position maintaining pawl with a single integrated structure is used, then the device structure is simple, but the releasing action becomes rough due to shock between the release member and the pawl
Solution Approach 1:
The position maintaining pawl is divided into a first pawl part and a second pawl part that are separate from each other. The first pawl part includes a positioning portion and a holding portion, while the second pawl part includes a release portion and a contact portion. This segmentation allows independent optimization of each part's function, reducing shock during release operations and improving releasing action smoothness.
2Ease of manufacture
If the position maintaining pawl is made as a single integrated component, then the manufacturing process is simple, but the material selection is limited
Solution Approach 1:
By dividing the pawl into separate first and second pawl parts, the invention enables selection of different materials for each part based on specific functional requirements. The first pawl part can be made from one material optimized for positioning and holding, while the second pawl part can be made from another material optimized for release and contact functions, thus expanding material selection versatility.
3Speed
If the release portion is positioned closer to the release member, then the release action is more direct, but shock between the release member and release portion increases
Solution Approach 1:
The second pawl part acts as an intermediary between the release member and the positioning ratchet. The contact portion of the second pawl part contacts the positioning ratchet first, and only after this contact is established does the release portion of the second pawl part contact the release member. This intermediary arrangement reduces shock by distributing the impact force across multiple contact points and timing the interactions sequentially.
Solution Approach 2:
The positioning ratchet contacts and moves the contact portion of the second pawl part away from the positioning ratchet before the release member contacts the release portion. This preliminary action prepares the system for release by pre-positioning the contact portion, reducing the shock that would occur if the release member directly impacted the release portion without this preparatory movement.
Data Source
AI summary
A bicycle operating device includes a support structure, a release member, a positioning ratchet and a position maintaining pawl. The release member is movable between first and second positions. The positioning ratchet has positioning ratchet teeth that establish predetermined positions. The position maintaining pawl is movable between a ratchet maintaining position and a ratchet releasing position. The position maintaining pawl includes a positioning portion, a holding portion, a release portion and a contact portion. The positioning portion moves away from the positioning ratchet, while the contact portion and the holding portion move toward the positioning ratchet teeth as the release member contacts and moves the release portion away from the release member as the release member moves in a releasing direction. The release portion moves away from the release member in response to movement of the positioning ratchet contacting and moving the contact portion away from the positioning ratchet.