Pleated Screen Crossbar Structure for Hidden Guide Cords
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Solution Overview
Problem
Existing screen devices with cord-guided crossbars face manufacturing difficulties due to sharp edges from holes in C or hollow profiles, which hinder movement and damage guide cords, especially in tight spaces like campers.
Innovation Solution
The crossbars are formed by two parallel profiles with a space between them to accommodate a strip with holes for guide cords, allowing for easy deburring and rounding of edges, making the manufacturing process simpler and reducing guide cord damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If holes are made in C or hollow profiles for guide cords, then the crossbar can be manufactured with a closed profile structure, but sharp edges at the holes hinder movement and may damage guide cords
Solution Approach 1:
The crossbar is divided into two separate profile parts that are arranged parallel to each other. This segmentation eliminates the need for holes in a closed profile, as the guide cords pass through the space between the two profile parts. The segmentation resolves the contradiction by maintaining structural integrity while eliminating sharp edges that could damage guide cords.
Solution Approach 2:
The guide cords are nested within the space between the two profile parts of the crossbar. This nesting arrangement allows the guide cords to be protected and guided smoothly without contacting sharp edges, while the closed profile structure is maintained for structural strength.
2Ease of manufacture
If holes are made in crossbars for guide cords, then the crossbar structure is simplified, but deburring and rounding edges is difficult particularly on the inside of profiles
Solution Approach 1:
By segmenting the crossbar into two separate profile parts, the invention eliminates the need for holes entirely. The guide cords pass through the gap between profiles rather than through holes, completely avoiding the manufacturing difficulty of deburring and rounding edges inside closed profiles.
Solution Approach 2:
The harmful feature (sharp edges from holes) is extracted by removing the holes from the design. The guide cord passage is created as an open space between profiles rather than as holes, eliminating the manufacturing precision problem entirely.
3Device complexity
If guide cords are visible between flanges of C profile, then the crossbar structure is simple, but it interferes during manual handling of the crossbar
Solution Approach 1:
The guide cords are nested within the space between the two profile parts, making them invisible from the outside while maintaining the simplicity of the crossbar structure. This nesting resolves the contradiction by hiding the cords during manual handling while keeping the overall structure simple.
Solution Approach 2:
The space between the two profile parts acts as a protective enclosure for the guide cords, similar to a flexible shell. This enclosure hides the cords from view and prevents interference during manual handling, while maintaining structural simplicity.
Data Source
AI summary
A screen device intended for a window or a door in a building or vehicle. The device includes a first elongated frame part having two ends; a further frame part and a third one, respectively, being arranged at each end of the first frame part at right angles to the first frame part and connected to a first one of its two ends. Two crossbars are arranged in parallel to the fixedly arranged first frame part and movable independently of each other along the two further frame parts. A pleated screen element is arranged between the first crossbar and the second crossbar, and the crossbars are guided by guide cords. At least one of the crossbars is formed by two profiles that are arranged in parallel to each other and leave a space between them in which a strip provided with holes for respective ones of the guide cords is received.