Internal Limit Nuts for Architectural Covering Travel Control
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Solution Overview
Problem
Architectural opening covering assemblies, such as blinds and shades, often require visible positive stops on the flexible covering to define travel limits, which are aesthetically unappealing and can become less effective due to skew over time, leading to reduced functionality.
Innovation Solution
The implementation of a dual travel limit assembly within the rotatable roller tube, utilizing first and second limit nuts that define the raised and lowered positions of the covering without external stops, allowing for adjustable travel limits and elimination of uncaptured loops, ensuring full window coverage and improved appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visible positive stops are used on the flexible covering to define travel limits, then the travel limits are clearly defined, but the aesthetic appearance deteriorates and effectiveness reduces over time due to skew
Solution Approach 1:
The patent removes the visible positive stops from the flexible covering and relocates the travel limit function to internal components (limit nuts on threaded members) within the headrail assembly. This extraction eliminates the aesthetic problem of visible stops while maintaining the functional requirement of defining travel limits through the relation: limit nut position → threaded member rotation → roller tube rotation → covering position control
Solution Approach 2:
The patent introduces threaded members and limit nuts as intermediary mechanical components between the user's operation and the covering's travel limits. These intermediaries translate rotational motion into precise positional control without requiring visible stops on the covering itself, thereby maintaining both aesthetic appearance and travel limit effectiveness
2Reliability
If visible positive stops are used on the flexible covering, then travel limits are defined, but the device complexity increases due to additional components on the covering
Solution Approach 1:
The patent merges the travel limit definition function into the existing headrail assembly by integrating limit nuts and threaded members with the roller tube mechanism. This consolidation eliminates the need for separate positive stop components on the flexible covering, reducing overall device complexity while maintaining travel limit reliability
Solution Approach 2:
The threaded members serve multiple functions: they provide the mechanical interface for the limit nuts, enable adjustable travel limit positioning, and integrate with the roller tube rotation mechanism. This multi-functionality reduces the need for additional dedicated components, thereby reducing device complexity
3Adaptability or versatility
If adjustable travel limits are implemented within the roller tube, then adaptability to various window dimensions is improved, but the device complexity increases
Solution Approach 1:
The patent implements adjustable travel limits through rotatable limit nuts on threaded members, allowing the travel limit positions to be dynamically repositioned according to different window dimensions. The adjustability is achieved by rotating the limit nuts along the threaded members, which translates to rotational adjustment of the roller tube and corresponding covering position, providing adaptability without requiring complex mechanical structures
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 solution provides effective travel limits for architectural opening coverings without visible stops, ensuring complete window coverage and reducing the appearance of uncaptured loops, while allowing for easy adjustment to meet various window dimensions and improving the operational stability of the covering assembly.
Implementation Method 1
a first limit nut threadably engaging the second threaded member and cooperating with a first fixed stop to define the lowered position, and a second limit nut threadably engaging the first threaded member and cooperating with a second fixed stop to define the raised position
Data Source
AI summary
Methods and apparatus to provide upper and lower travel limits for architectural opening coverings are disclosed. A disclosed architectural opening covering assembly includes a rotatable roller tube and a covering mounted to the roller tube. The covering is movable between a lowered position and a raised position. The covering is wound on the roller tube in the raised position. The covering assembly further includes a first limit nut located internal to the roller tube to define the lowered position, and a second limit nut located internal to the roller tube to define the raised position.