Brake Lever Retaining Formation for Push Rod
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Solution Overview
Problem
Existing brake systems face issues with push rod misalignment and disengagement, particularly in cold weather conditions, due to increased lubricant viscosity and complex assembly processes, leading to reduced brake responsiveness and increased maintenance costs.
Innovation Solution
A retaining formation combining a pinned connection and a ball and socket joint, along with a snap fit/snap fit connection, is used to securely attach the push rod to the brake lever, allowing for relative rotational movement while preventing axial separation, and utilizing a resilient clip or peening to ensure secure assembly and ease of servicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a ball and socket joint is used to allow rotational movement of the push rod, then the push rod can articulate perpendicular to its main axis, but the push rod can return before the lever in cold weather causing disengagement and misalignment
Solution Approach 1:
The patent combines a ball and socket joint with a retaining formation that includes a pin and bore. The ball (on the push rod) fits into the socket (on the lever), while the pin inserted through aligned bores in both components creates a retaining formation. This merging allows rotational articulation while preventing disengagement, resolving the contradiction between adaptability and reliability.
2Reliability
If a pinned joint is used to secure the push rod to the lever, then the connection is secure, but the assembly complexity and manufacturing cost increase due to additional bores and pin installation
Solution Approach 1:
The patent merges the ball and socket joint with the pinned connection into a single integrated retaining formation. The pin passes through bores in both the lever and push rod, combining the articulation function of the ball and socket with the securing function of the pin. This reduces assembly complexity compared to implementing these as separate components.
3Ease of operation
If a large diameter bore is used to allow free movement of the push rod at extreme ends of lever rotation, then the push rod can move freely, but misalignment and jamming of the brake occurs
Solution Approach 1:
The patent applies local quality by providing different geometric features at different locations of the retaining formation. The ball and socket joint provides local articulation capability for perpendicular motion, while the pin and bore provide local constraint to maintain alignment. This localized differentiation allows both freedom of motion and alignment precision.
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 effectively mitigates push rod misalignment and disengagement, ensuring reliable brake operation across varying conditions and simplifying assembly and maintenance by providing a secure, yet easily assembled connection.
Implementation Method 1
The retaining formation may be a resilient clip having a substantially U-shaped member to at least partially surround a brake lever
Implementation Method 2
The retaining formation may be formed by peening
Data Source
AI summary
A retaining formation defined on a brake lever of an air disc brake includes a push fit/snap fit connection for releasably securing a push rod to a brake lever. The retaining formation can include a pinned connection and a ball and socket joint, and a main axis of the pinned connection is coincident with a center of rotation of the ball and socket joint. The retaining formation can include a concave formation on one of the push rod and the brake lever and a corresponding convex formation on the other of the push rod and the brake lever. The concave formation at least partially surrounds the convex formation to prevent axial separation of the push rod and the brake lever. A method of assembling a brake subassembly includes the steps of assembling a push rod and a brake lever including a retaining formation such that at least a portion of the retaining formation deforms during assembly and resiles when the push rod is assembled to the brake lever to provide a snap fit connection therebetween. Another method of manufacturing a retaining formation includes the steps of providing one of a push rod and a brake lever with a concave formation, providing the other of the push rod and the brake lever with a convex formation able to receive the concave formation, assembling the concave formation and the convex formation, mechanically working the one of the push rod and the brake lever with the concave formation such that the concave formation at least partially surrounds the convex formation to prevent axial separation of the push rod and the brake lever.