Bicycle Shift Lever Independent Pivot Mechanism

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Solution Overview

Problem

Existing bicycle shift operating devices often require complex arrangements for independent operation of levers, which can lead to cumbersome designs and reduced ease of use.

Innovation Solution

A bicycle shift operating device featuring a base member, shift unit, first and second operating levers, and biasing elements that allow independent operation of the levers, with the first operating lever biased to a rest position and the second lever able to move independently without moving the first lever, simplifying the arrangement and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a complex arrangement is used to enable independent operation of operating levers, then the levers can operate independently, but the device complexity increases

Engineering Contradiction:
Improveindependent operation of leversVSAvoidarrangement complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The operating levers are segmented into independent pivotable units, each capable of independent operation. The first operating lever is pivotally mounted relative to the base member about a first pivot axis, while the second operating lever is pivotally mounted on the first operating lever about a second pivot axis, allowing each lever to function independently without complex coupling mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs dynamic biasing elements (springs) that automatically adjust to maintain the first operating lever at its rest position while allowing the second operating lever to move independently. The first biasing element biases the first operating lever towards the first rest position, and the second biasing element biases the first operating lever towards the first rest position in response to independent movement of the second operating lever, enabling independent operation without complex mechanical constraints.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the second operating lever is mounted on the first operating lever, then the structure is simplified, but the first operating lever may move unintentionally when the second lever operates

Engineering Contradiction:
Improvestructural simplicityVSAvoidposition stability of first lever
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The first biasing element acts as a counterbalancing mechanism that applies a restoring force to the first operating lever, keeping it at its rest position while the second operating lever moves independently. This biasing force counteracts any unintended movement of the first lever caused by the operation of the second lever, maintaining positional stability without requiring complex mechanical constraints.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Stability of the object's composition

If biasing elements are used to maintain rest positions, then lever positioning is improved, but the device complexity increases

Engineering Contradiction:
Improvelever positioningVSAvoidnumber of biasing elements
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The biasing elements serve multiple functions: the first biasing element maintains the first operating lever at its rest position, while the second biasing element not only maintains the first operating lever at rest but also responds to independent movement of the second operating lever. This multi-functional use of biasing elements achieves stable lever positioning with a relatively simple arrangement, avoiding the need for additional complex positioning mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This design enables a more straightforward and efficient operation of the shift operating device, allowing for independent movement of levers without the need for complex mechanisms, enhancing user experience and device simplicity.

Implementation Method 1

The first biasing element biases the first operating lever towards the first rest position to keep the first operating member at the first rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The second biasing element biases the first operating lever towards the first rest position in response to independent movement of the second operating lever from the second rest position to the second shifting position while the first operating lever remains at the first rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2535255B1Bicycle shift operating device
Publication Date: 2017.03.22 SHIMANO INC
  • EP2535255B1 patent drawingFigure 1
  • EP2535255B1 patent drawingFigure 2~3
  • EP2535255B1 patent drawingFigure 4~5

AI summary

A bicycle shift operating device is basically provided with a base member, a shift unit, a first operating lever, a second operating lever, a first biasing element and a second biasing element. The first operating lever operates the shift unit by pivoting about a first pivot axis between a rest position and a shifting position. The second operating lever operates the shift unit by pivoting about a second pivot axis on the first operating lever between a rest position and a shifting position. The first biasing element biases the first operating lever towards the first rest position to keep the first operating member at the first rest position. The second biasing element biases the first operating lever towards its rest position in response to independent movement of the second operating lever from its rest position to its shifting position while the first operating lever remains at its rest position.