Overrunning Brake Assembly for Gravity-Stable Coverings
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Solution Overview
Problem
Conventional brake assemblies in architectural-structure coverings introduce excess drag and lag, rendering them unusable with smaller coverings and causing unwanted movement due to gravity, leading to displeasing aesthetics and complaints.
Innovation Solution
A brake assembly incorporating a hub, wrap spring, drum, and one-way gear that allows free rotation in one direction while inhibiting rotation in the opposite direction, using frictional forces to maintain the covering's position against gravity, which can be overcome by a sufficient human force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional brake assembly is used to maintain the covering's position, then the covering can be held in place, but excess drag and lag are introduced, causing unwanted movement and rendering the brake unusable with smaller coverings
Solution Approach 1:
The brake assembly transitions from a static friction-based system to a dynamic overrunning clutch mechanism that adapts its state based on rotation direction. The clutch engages only when rotation reverses, providing position holding without continuous drag during normal operation. This dynamic behavior eliminates the constant friction drag of conventional brakes while maintaining reliability when needed.
Solution Approach 2:
The harmful continuous friction drag is extracted from the system by replacing the conventional brake with an overrunning clutch that provides intermittent engagement only during direction reversal. The clutch isolates the position-holding function from the continuous operation, allowing the covering to move freely during extension/retraction while preventing unwanted movement only when necessary.
2Stability of the object's composition
If a conventional brake assembly is used to prevent unwanted movement, then position stability is achieved, but lag and excess force are required to overcome the brake, leading to displeasing aesthetics
Solution Approach 1:
The overrunning clutch provides dynamic engagement that matches the operational requirements: it remains disengaged during smooth extension and retraction operations, then automatically engages only when rotation direction reverses to provide position stability. This eliminates the lag and rough operation of conventional brakes that require continuous friction-based holding.
Solution Approach 2:
The overrunning clutch acts as an intermediary mechanism between the driving force and the covering, providing smooth operation during normal movement while automatically engaging to prevent unwanted movement during direction reversal. This intermediary device eliminates the direct friction contact of conventional brakes, resulting in smoother operation and better aesthetics.
3Reliability
If the brake assembly engages immediately to prevent movement, then position holding is effective, but it prevents smooth operation and creates unwanted movement due to lag
Solution Approach 1:
The overrunning clutch dynamically adjusts its engagement state based on the direction of rotation, remaining disengaged during normal operation to eliminate lag, then automatically engaging when rotation reverses to provide immediate position holding. This dynamic response eliminates the time loss associated with conventional brake engagement while maintaining effective position holding.
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
Minimizes drag and unwanted movement, ensuring smooth operation and maintaining the covering's position without excess force, suitable for a wide range of architectural-structure coverings.
Implementation Method 1
a brake assembly incorporating a hub, wrap spring, drum, and one-way gear that allows free rotation in one direction while inhibiting rotation in the opposite direction, using frictional forces to maintain the covering's position against gravity
Implementation Method 2
a brake assembly incorporating a hub, wrap spring, drum, and one-way gear that allows free rotation in one direction while inhibiting rotation in the opposite direction
Implementation Method 3
using frictional forces to maintain the covering's position against gravity, which can be overcome by a sufficient human force
Data Source
AI summary
A brake assembly for use in an architectural-structure covering. The architectural-structure covering includes a rotatable member and a covering movable between a retracted position and an extended position. The brake assembly is operatively coupled to the rotatable member. The brake assembly is arranged and configured to permit rotation of the rotatable member in a first direction and to inhibit rotation of the rotatable member in a second or opposite direction to maintain a desired position of the covering. For example, the brake assembly is arranged and configured to prevent, or at least inhibit, unwanted extension of the covering due to the force of gravity. In some embodiments, the brake assembly includes a hub, a wrap spring, a drum, a one-way gear (e.g., a running gear such as, for example, a pinion or spur gear), and a housing.