Internal Adjustable Limit Stop Mechanism for Roller Shades

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Solution Overview

Problem

Existing architectural covering assemblies for windows and doors often rely on external limit devices that are unreliable, aesthetically undesirable, and consume space, and consumers face challenges in adjusting travel limits to accommodate fabric settling or personal preferences.

Innovation Solution

An architectural covering assembly with adjustable and fixed travel limits entirely disposed within the roller tube, allowing for fine adjustments of the extension and retraction limits by an installer or user, using a mechanism that includes limit screws and nuts, where the adjustable limit can be adjusted via a tool through an opening in the end plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external limit devices are used to provide travel limits for roller shades, then the travel limits can be provided, but the devices are unreliable, aesthetically undesirable, and consume space

Engineering Contradiction:
Improvereliability of travel limit mechanismVSAvoidexternal limit devices
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the limit mechanism from external placement and relocates it entirely inside the roller tube. The limit screws and nuts are positioned within the hollow interior of the roller tube, eliminating the need for external limit devices that protrude outward. This internalization resolves the contradiction by removing the aesthetic and spatial drawbacks of external devices while maintaining their limiting function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent nests the limit mechanism within the roller tube structure. The limit screws are positioned inside the hollow roller tube, with their protruding ends extending into the tube's interior space. The limit nuts thread onto these screws from the inside, creating a compact nested arrangement that fits within the roller tube's hollow interior. This nesting eliminates external devices while preserving the travel limit function.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If fixed travel limits are used in the roller tube, then the mechanism is simple, but the limits cannot be adjusted for fabric settling or consumer preferences

Engineering Contradiction:
Improveadjustability of travel limitsVSAvoidadjustable limit mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements adjustability by allowing the limit screws to be selectively repositioned along the roller tube's interior surface. The limit screws can be rotated or shifted to change the position where they engage with the limit nuts, thereby adjusting the travel limits. This dynamic capability enables adaptation to fabric settling and consumer preferences while maintaining a relatively simple internal mechanism.

Inventive Principle:
Principle #15Dynamics

3Shape

If limit mechanism is disposed entirely inside the roller tube, then aesthetics are improved and space is saved, but adjustment becomes more difficult

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidadjustability of limit
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The patent introduces a tool as an intermediary to facilitate adjustment of the internal limit mechanism. The tool is inserted through an opening in the end plate to engage with and reposition the limit screws or nuts from the inside of the roller tube. This intermediary tool enables easy adjustment of the internal limit mechanism without requiring disassembly of the roller tube, thus maintaining aesthetic appearance while improving ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3309347B1Adjustable internal double limit stop for roller shades
Publication Date: 2021.12.15 HUNTER DOUGLAS INC
  • EP3309347B1 patent drawingFigure 1
  • EP3309347B1 patent drawingFigure 2
  • EP3309347B1 patent drawingFigure 3

AI summary

An architectural covering assembly (100) includes a rotatable roller tube (104), a covering (106) coupled to the rotatable roller tube (104), and first and second limit screws (124,126) each having respective first and second ends. The second end of the first limit screw (126) engages the first end of the second limit screw (124). One of the limit screws(124) is rotationally and axially fixed with respect to an end plate (122). The other of the limit screws (126) is movable between rotationally locked and rotationally unlocked positions with respect to the end plate (122). Limit nuts (128,130) are threadably coupled to external threads of the limit screws (124,126). In the rotationally locked position the one of the limit screws is axially and rotationally fixed with respect to the end plate (122), and in the rotationally unlocked position the other of the limit screws is rotationally movable with respect to the end plate to adjust an extension or retraction limit of the covering (106).