Bicycle Pedal Compression Spring for Axial Play and Binding
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Solution Overview
Problem
Existing bicycle pedals experience binding issues due to axial play and tolerance variations, which can be exacerbated by weather, contamination, and extreme longevity, leading to bearing damage and reduced performance.
Innovation Solution
A bicycle pedal design featuring a compression spring on the spindle to maintain the pedal's position, combined with an elastomeric seal and multiple bearings, ensures proper loading and minimizes axial play within specified tolerances, preventing binding and enhancing bearing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pedal is rigidly fixed to the shaft, then the bearing alignment is precise, but axial play causes binding due to tolerance variations and environmental factors
Solution Approach 1:
The patent applies the dynamics principle by replacing the rigid fixed connection with a dynamic spring-based connection. The compression spring allows the pedal to move axially relative to the shaft, accommodating tolerance variations and environmental changes while maintaining reliable operation without binding. This dynamic adjustment mechanism resolves the contradiction between precise alignment and binding prevention.
Solution Approach 2:
The patent applies parameter changes by introducing a spring mechanism that changes the physical state of the connection from rigid to compliant. The spring allows controlled axial movement, changing the positional parameter of the pedal relative to the shaft, thereby preventing binding while maintaining functional alignment under varying operating conditions.
2Reliability
If the pedal allows axial movement to prevent binding, then reliability improves, but bearing alignment precision deteriorates
Solution Approach 1:
The spring-based connection creates a dynamic system where the pedal can move axially within controlled limits. This dynamic capability prevents binding while the spring's elastic properties maintain adequate bearing alignment through its force-exerting action, resolving the contradiction between movement freedom and alignment precision.
Solution Approach 2:
The spring acts as an intermediary element between the pedal and the shaft. It mediates the interaction by allowing controlled movement while maintaining force transmission and alignment. The spring's elastic deformation absorbs tolerance variations and environmental changes, preventing binding while preserving functional alignment.
3Reliability
If springs are added to the pedal, then axial shock is absorbed, but device complexity increases
Solution Approach 1:
The spring mechanism serves multiple functions simultaneously: it absorbs axial shocks, prevents binding caused by tolerance variations, and maintains bearing alignment through its elastic force. By combining these functions into a single component, the patent reduces overall device complexity while achieving multiple reliability improvements.
Solution Approach 2:
The patent merges the shock absorption function with the binding prevention function into a single spring mechanism. This consolidation eliminates the need for separate components for each function, thereby reducing device complexity while achieving both shock absorption and binding prevention through the same elastic element.
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 design effectively reduces axial play to zero to 0.100 inch, maintaining optimal bearing alignment and preventing binding, while the elastomeric seal protects against environmental factors, ensuring smooth operation and extended lifespan.
Implementation Method 1
a spring, coaxially placed on the pedal shaft, to maintain the position of the pedal on the shaft
Implementation Method 2
an elastomeric seal and multiple bearings, ensures proper loading and minimizes axial play
Data Source
AI summary
Improvements in a bicycle pedal that uses a compression spring placed along the spindle of the pedal to maintain position of the pedal on the spindle and allow for tolerance and assembly variation. The spring ensures proper loading on the bearings and allows for tolerance build-up of the pedal and bearings to eliminate binding. The play is eliminated as the spring biases out the maximum and minimum tolerance of the parts used in the pedal. The design uses an elastomeric seal at the crank connection side. The seal allows the shaft to be pressed into the pedal and through one or a plurality of bearings where it can be secured with the fastener under the spring tension.