Belt for a slat blind, method for manufacturing a belt and device for use in such a manufacturing method
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Solution Overview
Problem
Existing carrier strips for venetian blinds, made from polyester threads, suffer from non-uniform thickness, high rigidity, rough surface, and fraying, leading to uneven rolling and reduced service life.
Innovation Solution
A carrier tape produced using high-strength, thermoplastic, spun-dyed polyester yarns woven into a fabric structure with a quasi-continuous heat setting and smoothing process using a hot press, ensuring uniform thickness and adjustable rigidity, while maintaining color fastness and UV resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fabric tape is stretched and fed to a calender for heat setting and thickness adjustment, then the tape undergoes thickness adjustment and heat setting, but the resulting tape has non-uniform thickness, rough surface, and high rigidity
Solution Approach 1:
The patent changes the physical-chemical parameters of the polyester fibers by using spun-dyed thermoplastic fibers with specific crystallization characteristics. The fibers are heat-set at temperatures between 80°C and 150°C to control crystallization during stretching, which fundamentally alters the material's response to mechanical processing and enables uniform thinning without surface degradation
Solution Approach 2:
The patent implements a periodic stretching process where the tape is stretched in multiple passes with intermediate relaxation periods. This allows controlled, progressive thinning that maintains surface smoothness while achieving uniform thickness, avoiding the single-pass aggressive stretching that causes surface roughening
2Reliability
If the fabric tape is processed through chemical baths for finishing and coloring, then the tape achieves required color and finish, but the service life is reduced due to fraying
Solution Approach 1:
The patent applies preliminary edge sealing by heat-setting the tape edges before the main processing sequence. This pre-treatment creates a more stable edge structure that resists fraying during subsequent chemical baths and mechanical processing, significantly extending service life without affecting the coloring process
Solution Approach 2:
The patent uses composite construction with polyester fiber cores and protective edge bindings. The spun-dyed thermoplastic fibers provide structural integrity while resistant edge treatments prevent fraying, creating a composite structure that maintains reliability throughout the service life
3Productivity
If a calender is used for smoothing the fastener tape, then surface smoothness is achieved, but the feed rate becomes extremely low making the process inefficient
Solution Approach 1:
The patent performs preliminary smoothing during the weaving process by using tension-controlled loom settings that produce a pre-smoothed fabric structure. This preliminary action reduces the burden on subsequent calendering, allowing faster feed rates while maintaining surface quality
Solution Approach 2:
The patent replaces the traditional mechanical calendering system with a combination of controlled stretching and heat-setting processes. This substitution uses thermal and mechanical fields more efficiently to achieve smoothing at higher speeds, eliminating the bottleneck of slow mechanical pressure application
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
The solution results in a tape with consistent thickness, high tear strength, and improved durability, maintaining over 350 N tear strength after 1000 hours of UV exposure, with elongation of less than 1.3% and acceptable stiffness for drapability, enhancing the service life and operational efficiency of venetian blinds.
Implementation Method 1
heat setting and smoothing of a woven strip in the manufacture of a carrier strip
Implementation Method 2
The dry, finished fabric strip is stretched in the longitudinal direction and then fed to a calender, where heat setting and thickness adjustment of the strip takes place
Implementation Method 3
a relatively inelastic band results even after weaving, which has an elongation of a maximum of 1.3% by stretching and subsequent heat setting
Data Source
Figure 1~2
AI summary
The invention relates to a carrier strip for venetian blinds, a method for producing a carrier strip for venetian blinds and a device (10) for quasi-continuous heat setting and smoothing of a woven strip (20) in the manufacture of a carrier strip for venetian blinds. This carrying tape is made of an inelastic, stretched, heat-set fabric, which consists of thermoplastic, high-strength, spun-dyed threads and has a high tear strength of more than 700 N, a low elongation of a maximum of 1.3%, a small variation in thickness of less than 0.015 mm, if necessary a has a defined rigidity and a mirror-smooth surface on both sides of the fastener tape. Due to these properties, the fastener tape has a longer service life (Fig. 1).