Bicycle Gearshift Actuator Fastening Release Mechanism
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Solution Overview
Problem
Existing actuator devices for bicycle gearshifts are bulky and complex due to the number of components and space occupation, particularly in the arrangement of levers and torsion springs, which can lead to compromised performance under impacts or deformations.
Innovation Solution
A compact actuator device with a fastening/release mechanism featuring a rotatable first member, a second member, and an elastic element that switches between a fastening and release operative condition based on stress levels, allowing the connection rod to rotate as a unit with the motion transmission element under normal stress and freely in case of excessive stress, thus absorbing impacts without transferring them to the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fastening/release mechanism with levers and torsion springs is provided to protect against excess stresses, then the gearshift is protected against impacts and deformations, but the device becomes bulky and complex with increased space occupation
Solution Approach 1:
The patent combines the fastening and release functions into a single integrated mechanism where the elastic element directly couples the motion transmission shaft and connection rod. This eliminates the need for separate levers and multiple torsion springs, reducing component count while maintaining protection functionality through the elastic element's inherent ability to absorb excess stresses and allow controlled slippage.
2Reliability
If a fastening/release mechanism with levers and torsion springs is provided to protect against excess stresses, then the gearshift is protected against impacts and deformations, but the device occupies significant space
Solution Approach 1:
The patent merges the protective function into a compact arrangement where the elastic element is positioned between the motion transmission shaft and connection rod, eliminating the space required for external levers and multiple springs. This integrated design achieves impact protection with minimal space occupation.
Solution Approach 2:
The elastic element is nested within the existing actuator structure, utilizing the space between the motion transmission shaft and connection rod. This nesting approach allows the protective mechanism to be accommodated within the existing footprint without requiring additional external space.
3Reliability
If multiple components like levers and torsion springs are used in the fastening/release mechanism, then the protection function is achieved, but the overall design becomes simpler in terms of total number of components
Solution Approach 1:
The patent merges multiple protective components (levers and torsion springs) into a single elastic element that performs the fastening and release functions. This consolidation reduces the total number of components while maintaining the essential protective functionality through the elastic element's ability to engage and disengage based on stress levels.
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 more compact and simpler design that effectively absorbs undesired impacts and deformations, maintaining structural integrity and allowing manual operation for gear selection, while reducing the risk of mechanical interference and damage.
Implementation Method 1
an elastic element operatively arranged between the first member and the second member and that exerts a predetermined pre-load stress on the first member and on the second member
Implementation Method 2
a torsion spring that pushes the driven member against the driving member
Data Source
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AI summary
The invention relates to an actuator device for a bicycle gearshift, comprising an actuation linkage, a drive member configured to control the deformation of the actuation linkage and comprising a motion transmission element (122) having a rotation axis (X), and a fastening/release mechanism (150) operatively arranged between the motion transmission element (122) and a connection rod (102) of the actuation linkage. The fastening/release mechanism (150) comprises a first member (160) rotatable about the rotation axis (X) as a unit with said motion transmission element (122), a second member (170) rotatable about the rotation axis (X) together with said connection rod (102), an elastic element (180) operatively arranged between the first member (160) and the second member (170) and that exerts a predetermined pre-load stress on the first member (160) and on the second member (170). The fastening/release mechanism (150) is selectively configurable in a fastening operative condition in which the first member (160) is rotatable about the rotation axis (X) as a unit with the second member (170), and in a release operative condition in which the first member (160) and the second member (170) can rotate with respect to one another about the rotation axis (X).