Canted Disc Stretching of Elastic Strip Edges Without Splice Grip Loss
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Solution Overview
Problem
Conventional methods for stretching elastic strips in the cross-machine direction face issues such as loss of grip on the elastic strip due to splicing tape, leading to contraction and production delays, and require manual repositioning, resulting in downtime and interruptions.
Innovation Solution
An apparatus with rotatable discs featuring apertures and rows of teeth configured to engage and hold the elastic strip using vacuum pressure, maintaining tension and preventing contraction, while allowing for seamless rethreading during splicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If splicing tape is used to attach elastic strip to new roll, then elastic strip can be continuously supplied, but the canted discs lose grip on the elastic strip edges causing contraction and production delays
Solution Approach 1:
The harmful splicing tape is removed from the system. Instead of using tape to join elastic strip rolls, the invention feeds the elastic strip roll directly into the processing mechanism, eliminating the tape and its associated grip-loss problems while maintaining continuous production capability
Solution Approach 2:
The elastic strip roll is pre-positioned and fed directly into the processing mechanism before any processing occurs. This preliminary feeding action eliminates the need for splicing tape and ensures the elastic strip is already in the correct position for continuous processing without grip loss
2Reliability
If manual repositioning of elastic strip edges onto canted discs is performed, then grip can be restored, but downtime increases and production is interrupted
Solution Approach 1:
The processing mechanism automatically maintains grip on the elastic strip edges through its design features (teeth or grooves on the discs) without requiring manual intervention. The system serves itself by continuously holding the elastic strip in place during processing and splicing operations, eliminating downtime associated with manual repositioning
3Shape
If canted discs are used to stretch elastic strip in cross-machine direction, then elastic strip can be stretched, but grip is lost during splicing causing contraction
Solution Approach 1:
The disc surfaces are equipped with localized features (teeth or grooves) at specific positions to enhance grip on the elastic strip edges. These localized features provide selective engagement points that maintain grip during splicing while allowing the overall disc structure to continue providing cross-machine direction stretching functionality
Solution Approach 2:
The elastic strip is pre-positioned on the discs with proper engagement before splicing occurs. This preliminary positioning ensures that when the new roll is fed, the strip maintains its stretched configuration and grip is preserved throughout the transition, preventing contraction
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 ensures consistent stretch and reduces downtime by maintaining elastic strip tension, minimizing waste, and enhancing production efficiency by eliminating the need for manual repositioning.
Implementation Method 1
The outer rims of the canted discs may comprise apertures that are fluidly connected to a vacuum pressure source so that vacuum air pressure may be used to hold the edges of the elastic strip on the outer rims of the discs during operation
Data Source
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AI summary
An apparatus (10) for stretching an elastic strip (16) in a cross-machine direction (CD), the apparatus (10) comprising a set of rotatable discs (34, 62) including: a first rotatable disc (36), and a second rotatable disc (40), whereby the first rotatable disc (36) is inclined at an angle with respect to the second rotatable disc (40). Each rotatable disc (36, 40) has an outer surface (36e, 40e) comprising at least one aperture (58) that is configured to be fluidly connected to a vacuum pressure source and configured to receive an edge of an elastic strip (16) at a pick-up location and hold the edge of the elastic strip (16) as the elastic strip (16) is advanced in the machine direction (MD) from the pick-up location to a drop-off location during operation, whereby the distance between the first rotatable disc and the second rotatable disc is greater at the drop-off location than at the pick-up location, thereby stretching the elastic strip (16) in the cross-machine direction (CD). The outer surface (36e, 40e) of each rotatable disc (36, 40) also comprises at least one row of teeth (52, 54) that extends around at least part of a periphery of a rotatable disc (36, 40), whereby the at least one row of teeth (52, 54) comprises a plurality of teeth (55, 57) each having a gripping end (69, 70), whereby each tooth of the plurality of teeth (55, 57) exhibits a maximum cross-section that is situated at a distance from at the gripping end (69, 70) of the tooth.