Clipless Bicycle Pedal Locking Mechanism with Cam
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Solution Overview
Problem
Clipless bicycle pedals face challenges such as requiring a fixture for assembly, coil spring-induced gouging, dynamic seals for rotation, mechanical play between loops, and lack of engagement force adjustment, leading to weight issues and compromised performance.
Innovation Solution
A clipless bicycle pedal design featuring a locking mechanism with a cam system between inner and outer loops that allows for locked and unlocked configurations without a coil spring, enabling assembly without a fixture, using static seals, reducing play, and allowing force adjustment through spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a coil spring is used to hold loops perpendicular to each other, then the locking mechanism can maintain proper orientation, but the spring causes gouging into the sleeve surface over time
Solution Approach 1:
The patent removes the coil spring from the locking mechanism, extracting the harmful element that caused gouging. Instead of using a spring to hold loops perpendicular, the invention uses a different mechanism that eliminates contact between the spring and sleeve, thereby preventing surface damage while maintaining loop orientation stability
Solution Approach 2:
The patent introduces a sleeve with specific geometric features that act as an intermediary between the loops and the force required to maintain perpendicular orientation. The sleeve's geometry provides the necessary constraints without requiring a spring that would gouge the surface
2Reliability
If a steel sleeve is used to prevent gouging, then the sleeve surface durability is improved, but the pedal weight increases significantly
Solution Approach 1:
By removing the coil spring entirely, the patent eliminates the need for a steel sleeve to prevent spring-induced gouging. This allows the use of lighter materials for the sleeve while maintaining durability, as there is no spring contact to cause wear
Solution Approach 2:
The patent enables the use of composite or lighter materials for the sleeve construction, combining durability requirements with weight reduction goals by eliminating the spring mechanism that necessitated heavy steel construction
3Ease of operation
If the sleeve is allowed to rotate within the pedal body, then the locking mechanism can function properly, but dynamic seals are required which are more susceptible to leaking
Solution Approach 1:
The patent separates the rotational function from the sealing function by designing the locking mechanism so that only the necessary components rotate while the sleeve remains stationary relative to the pedal body, allowing static seals to be used instead of dynamic seals
Solution Approach 2:
The locking mechanism is designed to achieve proper function through the interaction of its components without requiring the sleeve to rotate, allowing the system to self-accommodate the loops' orientation changes while maintaining a stable sealing interface
4Ease of manufacture
If the leg ends of the coil spring are not precisely located, then manufacturing is easier, but mechanical play occurs between loops that compromises cleat engagement
Solution Approach 1:
By removing the coil spring, the patent eliminates the manufacturing precision issue entirely. The locking mechanism achieves proper loop positioning through geometric constraints and component interactions that do not require precisely located spring leg ends
Solution Approach 2:
The patent replaces the spring-based positioning system with a geometry-based positioning system that uses the shapes and arrangements of rigid components to maintain proper loop orientation without relying on precise spring leg end locations
5Manufacturing precision
If a fixture is required to assemble the loop/spring mechanism, then the coil spring can preload the loops into perpendicular position, but consumer rebuilding without the fixture becomes impossible
Solution Approach 1:
By removing the coil spring and its associated fixture requirement, the patent enables consumers to rebuild the locking mechanism using standard tools. The perpendicular positioning is achieved through geometric constraints that do not require specialized assembly fixtures
Solution Approach 2:
The locking mechanism is designed to self-align and self-position the loops into the correct perpendicular orientation through the interaction of its components during normal assembly, eliminating the need for external fixtures and enabling consumer-friendly rebuilding
Data Source
AI summary
A clipless bicycle pedal including an axle, connectable to a bicycle crank arm, and a locking mechanism, connected to the axle, suitable to engage/disengage a cleat assembly of a cycling shoe. The locking mechanism includes a sleeve, inserted along the axle, an inner loop and an outer loop, inserted along the sleeve and free to rotate around the sleeve, so that the inner loop is contained within the outer loop. The locking mechanism further includes a cam, included between the inner loop and the outer loop, suitable to hold the inner loop and the outer loop in an engagement configuration of the cleat assembly. The cam is also suitable to allow rotational movement of the inner, outer loops relative to each other, from the engagement configuration to a disengagement configuration of the cleat assembly.