Resilient Slack Adjuster Link for Brake Travel Limit Protection
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Solution Overview
Problem
Automatic slack adjusters in commercial vehicle brakes can suffer from damage due to binding or excessive resistance in the force transmission path between the brake actuator and the slack adjuster, leading to potential deformation of components.
Innovation Solution
Incorporating a resilient portion in the adjustment link, such as a telescoping shaft arrangement or a spring mechanism, to accommodate excess actuator pushrod stroke and interaction forces, thereby preventing deformation and potentially eliminating the need for a torque limiting clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque limiting clutch is used to allow relative movement between the worm shaft and worm wheel when torque exceeds a threshold, then component damage is prevented, but device complexity increases
Solution Approach 1:
The patent removes the torque limiting clutch from the force transmission path between the actuator and slack adjuster. Instead, the resilient portion of the adjuster link itself provides the torque limiting function by yielding when excessive force is applied, thereby preventing component damage without requiring an additional clutch mechanism.
Solution Approach 2:
The resilient portion changes its mechanical properties (stiffness) based on the applied load. Under normal operating conditions, it remains rigid to transmit force efficiently. When excessive torque is applied, it yields or deforms, automatically limiting the torque transmitted to protected components, thus replacing the clutch's torque limiting function.
2Manufacturing precision
If the adjustment link is made rigid to ensure precise force transmission, then manufacturing precision is improved, but component damage risk increases due to binding or excessive resistance
Solution Approach 1:
The resilient portion acts as a pre-designed cushioning element that yields when excessive force or binding occurs in the force transmission path. This beforehand cushioning prevents the transmission of damaging forces to other components, protecting the system from harm while maintaining precise force transmission under normal conditions.
3Reliability
If a resilient portion is added to the adjustment link to accommodate excess stroke and forces, then component damage is prevented, but device complexity increases
Solution Approach 1:
The resilient portion of the adjuster link serves multiple functions simultaneously: it transmits force under normal conditions, limits torque when excessive force is applied, accommodates excess actuator stroke, and protects other components from damage. By integrating these functions into a single element rather than adding separate mechanisms, the overall device complexity is minimized.
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 resilient link design minimizes the risk of component damage by allowing axial displacement and adjusting the force threshold to ensure slack adjustment occurs before reaching the limit of travel, reducing the likelihood of deformation and potentially eliminating the need for additional clutch mechanisms.
Implementation Method 1
Incorporating a resilient portion in the adjustment link, such as a telescoping shaft arrangement or a spring mechanism, to accommodate excess actuator pushrod stroke and interaction forces
Implementation Method 2
A resilient portion 306 of the link 300 is formed in this embodiment in the upper portion 301. The resilient portion includes an outer tubular section 307 having a spring seat 308 at the dog-leg end of the tubular section 307.
Data Source
AI summary
A self-adjusting automatic slack adjuster for reducing slack in the brake of a vehicle includes an adjuster link having a resilient portion. When a brake application force being applied to the slack adjuster exceeds a level that could result in brake application linkage damage as a result of the slack adjuster's slack adjustment mechanism having reached a travel limit, the resilient portion of the adjuster link permits the axial length of the adjuster link to change to accommodate the high brake application force in order to minimize or preclude damage to the brake application linkage.