Shoe-Hold Pin Segmentation for Drum Brake Spring Retention
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Solution Overview
Problem
Conventional shoe-hold apparatuses for drum brake devices face inefficiencies in assembly and disengagement prevention, with limited engagement points leading to operational challenges and increased risk of disengagement during assembly and use.
Innovation Solution
A shoe-hold apparatus featuring a shoe-hold spring with one end opened slots and a shoe-hold pin with a disengagement preventive portion, where the shoe-hold pin's design includes a small diameter penetrating portion and a large diameter disengagement preventive portion, preventing lateral and rotational movement of the shoe-hold spring, ensuring secure engagement with the back plate and drum surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the shoe-hold spring is retained between the engagement head and the web using conventional methods, then the assembly structure is simple, but the shoe-hold spring can rotate with the engagement portion as fulcrum, creating disengagement risk
Solution Approach 1:
The shoe-hold pin is segmented into three functional portions: engagement head for initial retention, shaft for positioning, and disengagement preventive portion for securing. This segmentation allows each portion to perform its specific function, preventing rotation and disengagement while maintaining structural simplicity.
Solution Approach 2:
The disengagement preventive portion acts as an intermediary element between the shoe-hold spring and the web. It插 fits into the pin insertion hole to prevent the shoe-hold spring from rotating with the engagement portion as fulcrum, thereby eliminating the disengagement risk.
2Reliability
If the shoe-hold spring is forcefully deformed to engage with the concave seat, then engagement is achieved, but the operability becomes extremely inefficient
Solution Approach 1:
The shoe-hold spring is designed to be elastically deformable, allowing it to automatically adjust and engage with the disengagement preventive portion without requiring excessive external force. The elastic deformation enables self-engagement, improving assembly operability while ensuring reliable engagement.
3Device complexity
If only one engagement portion exists between the shoe-hold pin and shoe-hold spring, then the structure is simple, but pulling the shoe-hold spring causes rotation and potential disengagement
Solution Approach 1:
The shoe-hold pin is divided into multiple functional segments: the engagement head provides initial retention, the shaft provides positioning, and the disengagement preventive portion provides rotational constraint. This segmentation creates multiple engagement points that work together to prevent disengagement under pulling forces.
Solution Approach 2:
Different portions of the shoe-hold pin have different local qualities optimized for specific functions. The engagement head has a larger diameter for retention, the shaft has a reduced diameter for positioning, and the disengagement preventive portion has specific dimensions to prevent rotation. This local differentiation enhances overall reliability.
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 enhances assembly efficiency by eliminating the need for excessive force to maintain resilient deformation and effectively prevents disengagement of the shoe-hold spring, improving overall operability and reliability.
Implementation Method 1
a shoe-hold spring, which is a sheet metal bent to form a web side arm and a drum side arm... the shoe-hold spring is resiliently retained between the second head and the web
Data Source
AI summary
To accomplish both prevention of disengagement of the shoe-hold spring from the shoe-hold apparatus and improvement of the assemblability of the same. The shoe-hold pin has the small diameter portion and the large diameter portion. One end opened slots are formed at the pair of arms of the U-shaped shoe-hold spring, and the slots are such that the small diameter portion of the shoe-hold pin is passable therethrough and the large diameter portion is non-passable.The pin-insertion hole, which is continuous to the slot of the web side arm and may position the large diameter portion therein, is formed in the web side arm and restricts the shoe-hold spring from disengaging therefrom when the large diameter portion of the shoe-hold pin is positioned in the pin-insertion hole.