Elastic Thread Anchoring in Sanitary Product Sleeves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing elastic structures in absorbent sanitary products face challenges with the use of glue, including inconsistent dispensing, clogging, contamination, and quality issues due to high-frequency intermittent welding, particularly in creating alternating elastic and non-elastic portions.
Innovation Solution
An elastic structure and production method that uses continuous welding to anchor elastic threads within a tubular sleeve made of non-elastic flexible material, with specific welding configurations to ensure the thread is anchored in elasticized portions while free in non-elasticized portions, eliminating the need for glue and reducing vibrations and overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glue is used to anchor elastic threads to the substrate, then the elastic structure can be produced, but there is difficulty in ensuring constant quantities of glue dispensing, clogging, contamination, and need for welding to close structures
Solution Approach 1:
The patent removes the glue dispensing system entirely from the production process. Instead of using glue to anchor elastic threads, the invention uses a welding device that directly welds the elastic thread to the substrate through a continuous welding action, eliminating all problems associated with glue dispensing including clogging, contamination, and inconsistent application.
Solution Approach 2:
The patent replaces the mechanical glue dispensing system with a welding-based anchoring system. The welding device uses thermal or ultrasonic energy to create secure anchors in the substrate, substituting the chemical adhesive mechanism with a thermal/mechanical welding process that is more reliable and controllable.
2Adaptability or versatility
If high-frequency intermittent welding is used to create alternating elastic and non-elastic portions, then the desired structure is achieved, but vibrations produce decline in weld quality
Solution Approach 1:
The patent employs a dynamic welding wheel system where one welding wheel rotates continuously while the other remains stationary or rotates at a different speed. This dynamic configuration allows the welding wheels to be moved radially relative to each other to interrupt welding in non-elasticized portions while maintaining continuous rotation, thereby avoiding high-frequency intermittent welding vibrations and maintaining weld quality.
Solution Approach 2:
The patent implements periodic interruption of the welding action by radially moving the welding wheels relative to each other. The welding is continuously applied in elasticized portions while being periodically interrupted in non-elasticized portions, achieving the desired alternating structure without the quality decline associated with high-frequency intermittent welding.
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 approach allows for high-quality, glue-less elastic structures with alternating elasticized and non-elasticized portions, improving production efficiency and weld quality by maintaining consistent welding operations, avoiding the issues associated with high-frequency intermittent welding.
Implementation Method 1
The welds forming the connecting portions of the elastic thread are formed by a thermal or ultrasonic welding device
Implementation Method 2
The welds forming the connecting portions of the elastic thread are formed by a thermal or ultrasonic welding device
Implementation Method 3
When the longitudinal tensioning ceases, the thread tends to expand radially and remains anchored to the connecting portions by interference
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An elastic structure for absorbent sanitary products, comprising - a sleeve (12) comprising a first and a second layer (14, 16) overlapping each other, - at least one elastic thread (18), which extends within said sleeve (12) in a longitudinal direction, and - a plurality of first connecting portions (24) spaced apart in the longitudinal direction, wherein each of said first connecting portions (24) comprises two first welds (28) arranged on opposite sides of the thread (18), wherein the first welds (28) weld said first and said second layers (14, 16) to each other in a first longitudinal portion (20) of said sleeve (12), and wherein said first welds (28) of each of said first connecting portions (24) have respective proximal surfaces (30) facing the thread (18), spaced apart by a distance (D1) less than the diameter (D) of the untensioned thread, in order to anchor the thread (18) to said first longitudinal portion (20) of the sleeve (12), and - a plurality of second connecting portions (26) spaced apart in the longitudinal direction, wherein each of said second connecting portions (26) comprises at least one second weld (29), wherein said second welds (29) weld said first and said second layers (14, 16) to each other in a second longitudinal portion (22) of said sleeve (12) without axially connecting the thread (18) to said second longitudinal portion (22) of the sleeve (12).