Adjustable Cam Actuated Brake Assembly Wear Compensation
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Solution Overview
Problem
Existing cam actuated brake assemblies face issues with brake pad wear, requiring actuators with longer strokes or adjustable links, which can lead to disengagement of the wedge or cam and necessitate costly shutdowns for adjustments, especially in critical industries like oil drilling.
Innovation Solution
An adjustable cam actuated brake assembly featuring a cam with a piston and adjuster mechanism, allowing for rapid adjustment of the piston's position within a bore to compensate for brake pad wear without requiring shutdowns, using a notched piston and retaining pins to maintain proper alignment and engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the actuator stroke is increased to compensate for brake pad wear, then the brake pads can contact the disk over a larger range of wear, but the wedge or cam may disengage from the cam followers and the actuator loses applicable force and modulation capability
Solution Approach 1:
The actuator system is segmented into two independent functional components: a long-stroke actuator that provides the necessary travel range for worn brake pads, and a separate cam mechanism that maintains engagement reliability. The cam follower is positioned to follow the cam profile throughout the entire actuator stroke range, ensuring continuous engagement even with the extended stroke length.
Solution Approach 2:
The cam mechanism acts as an intermediary between the long-stroke actuator and the brake pads. It translates the linear motion of the long-stroke actuator into controlled rotational motion of the brake arms, maintaining proper force application and modulation while accommodating the extended stroke required for worn pads.
2Ease of operation
If an adjustable link is provided between the actuator and the wedge or cam to remove slack caused by brake pad wear, then proper operation can be maintained, but the brake must be stopped during adjustment causing expensive shutdown time
Solution Approach 1:
The brake assembly incorporates self-adjusting features through the cam mechanism design. As brake pads wear, the cam profile automatically compensates for the increased clearance, maintaining proper engagement without requiring manual intervention. The long-stroke actuator working with the cam mechanism provides automatic adaptation to wear conditions.
Solution Approach 2:
The system transitions from a static link length to a dynamic solution where the cam profile geometry adapts to different wear conditions. The cam's curved surface provides varying leverage and engagement characteristics that automatically adjust to the current pad thickness, eliminating the need for manual link adjustment.
3Ease of operation
If a traditionally used actuator with spring return is used in cam actuated brakes, then the actuator returns to fully retracted position when brake is not applied, but the wedge or cam becomes retracted from engagement causing contact surfaces to become fouled or misaligned
Solution Approach 1:
The cam mechanism is designed to maintain preliminary engagement of the cam follower with the cam profile even during actuator retraction. The cam's geometric profile ensures that the follower remains in contact with the cam surface throughout the retraction stroke, preventing disengagement and maintaining proper alignment of contact surfaces before the braking action is actually required.
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
Enables rapid and efficient adjustment for brake pad wear without disengagement, reducing downtime and operational costs by allowing for in-place adjustments without compromising braking performance or force modulation.
Implementation Method 1
frictionally engaging an object between the braking surfaces
Data Source
AI summary
In a cam actuated brake, an adjustable cam disposable intermediate a pair of following surfaces on first ends of a pair of arms. The arms being rotatable about parallel axes and having a pair of opposing brake surfaces at second ends. The cam comprises a body having a first and second opposite cam surfaces adapted to engage the following surfaces and a bore intermediate the cam surfaces and a piston receivable in the bore. The piston is releasably coupled to the bore. The cam further comprises an adjuster for varying the position of the piston in the bore. The piston may be engaged by an actuator so as to wedge the cam between the following surfaces of the arms so as to rotate the first and second arms about their respective axes thereby frictionally engaging an object between the braking surfaces.