Tapered Creel Bobbin Brake Strap for Stable Torque Control
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Solution Overview
Problem
The increasing complexity, cost, and footprint of creel systems due to the need for individual braking of numerous creel bobbins in tire reinforcement processes, which complicates the application of uniform tension to reinforcement wires.
Innovation Solution
A creel bobbin brake design featuring a strap that winds over at least one and a half revolutions around the bobbin shaft, with a tapering opening allowing the strap end to be inserted repeatedly, making brake torque independent of shaft friction and dependent on strap tension, thereby reducing complexity and cost while maintaining effective tension control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a helically wound strap is used around the shaft, then the brake torque is generated, but the strap tends to run-off to the side of the shaft
Solution Approach 1:
The strap is designed with asymmetric geometry featuring a tapered cross-section where the width decreases in the direction of winding. This asymmetric shape, combined with the tapering opening, creates a self-centering effect that prevents the strap from running off to the side while maintaining stable positioning around the shaft
Solution Approach 2:
The tapering opening is designed to accommodate the tapered strap body, creating a nested relationship where the strap fits progressively tighter with each revolution. The opening dimensions are specifically matched to the strap dimensions at each stage of winding, ensuring stable positioning without run-off
2Reliability
If the strap is wound over multiple revolutions, then the brake torque becomes more stable, but the friction between strap and shaft becomes more significant
Solution Approach 1:
The invention changes the geometric parameters of the strap and opening, specifically the taper angle and dimensional ratios, to optimize the balance between friction utilization and brake torque consistency. The specific parameter ranges are selected to achieve reliable braking while minimizing excessive friction losses
3Manufacturing precision
If individual braking mechanisms are provided for each creel bobbin, then uniform tension is achieved, but the complexity and footprint of the creel increase dramatically
Solution Approach 1:
The strap is designed as a simple, inexpensive, single-piece component that can be easily replaced. This disposable-like approach eliminates the need for complex, expensive individual braking mechanisms while maintaining tension uniformity across all bobbins
Solution Approach 2:
The flexible strap, with its tapered cross-section and opening, provides an elegant simple solution to the braking problem. This thin-film-like structure replaces complex mechanical braking systems, significantly reducing device complexity and footprint while achieving the required tension control
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 design simplifies the creel system by reducing the reliance on shaft friction for brake torque, ensuring consistent tension application across multiple windings, and minimizing the creel's physical footprint and operational complexity.
Implementation Method 1
the brake torque can be made almost solely dependent on tension in the strap and the diameter of the brake surface at the shaft
Data Source
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AI summary
The invention relates to a first creel bobbin brake (41, 141), a creel bobbin assembly (3, 103), a creel (1, 101) and a creel method. The first creel bobbin brake (41, 141) is arranged for applying a braking torque to a first shaft (31, 131) of a first creel bobbin (21). The first creel bobbin brake (41, 141) comprises a strap (5, 205) that is provided with a first end (51, 251), a second end (52, 252) and a strap body (50, 250) extending in a longitudinal direction between the first end (51, 251) and the second end (52, 252), wherein the strap (5, 205) further comprises an opening (53, 253) in the strap body (50, 250), wherein the strap body (50, 250) and the opening (53, 253) are arranged to taper from the first end (51, 251) towards the second end (52, 252), wherein the strap (5, 205) is arranged to be wound around the first shaft (31, 131) of the first creel bobbin (21) over at least two revolutions, wherein the second end (52, 252) is insertable through the opening (53, 253) with each revolution.