Heald Shaft Chamber Design for Corner Stability
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Solution Overview
Problem
Modern high-speed weaving machines experience failures at corner connections due to extreme accelerations and forces, which existing heald shaft designs, particularly those using aluminum components, struggle to withstand effectively.
Innovation Solution
A heald shaft design featuring two shaft bars with a cross-sectional profile that includes chambers to increase rigidity, a side support with a tab that engages in these chambers for enhanced stability, and a fastening device to securely lock the tab, reducing deformation and susceptibility to shear forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum shaft bars and side supports are used with a single screw corner connection, then the heald shaft can be lightweight and easy to assemble, but the corner connection fails under extreme accelerations and large forces during high-speed weaving
Solution Approach 1:
The shaft bar cross-section is segmented into multiple chambers (at least two chambers) separated by internal webs. This segmentation increases the moment of inertia and rigidity of the shaft bar without increasing its external dimensions or weight, allowing the aluminum structure to withstand the large forces generated during high-speed weaving while maintaining lightweight construction.
Solution Approach 2:
The corner connection uses a composite structure combining the aluminum shaft bar with a steel reinforcement element (spreader or insert) positioned in the chamber. This composite design leverages the high strength-to-weight ratio of steel at the critical corner connection point while maintaining the overall lightweight aluminum construction of the heald shaft.
2Strength
If the shaft bar has a solid cross-section, then it has high rigidity, but it increases mass and reduces the rigidity-to-mass ratio needed for modern high-speed weaving machines
Solution Approach 1:
The shaft bar is designed with a hollow cross-section containing at least two chambers separated by internal webs. This segmentation distributes material more efficiently, placing it farther from the neutral axis to maximize the moment of inertia and rigidity. The result is a shaft bar with high rigidity that is lighter than a solid cross-section of the same external dimensions.
Solution Approach 2:
Instead of increasing rigidity by adding material in the planar dimensions (which would increase weight), the design uses the depth dimension by creating internal chambers and webs that extend through the cross-section. This three-dimensional structural arrangement maximizes rigidity for a given mass by optimizing the distribution of material throughout the volume.
3Ease of manufacture
If a single screw is used for the corner connection, then assembly is quick and easy, but the connection point becomes the starting point for failure under operational loads
Solution Approach 1:
The corner connection employs a composite fastening system combining a steel reinforcement element (spreader or insert) with the aluminum shaft bar and side support. The steel element acts as a load-bearing insert that distributes stresses and prevents the connection from failing, while the overall assembly remains simple to manufacture and assemble using standard machining and assembly processes.
Data Source
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AI summary
Weaving shaft (1) having the following features: at least two shaft rods (2) extending substantially in the longitudinal direction (L) of the weaving shaft (1), at least one side support (3) extending substantially in the vertical direction (H) of the weaving shaft (1) and to which the at least two shaft rods (2) are attached at a distance (A) in the vertical direction (H), wherein the sides of the shaft rods facing each other in the vertical direction (H) are called inner sides (IS) and the sides facing away from each other are called outer sides (AS), wherein the at least one side support (3) is equipped with a flap (4) extending substantially in the longitudinal direction (L) of the weaving shaft (1), wherein at least one shaft rod (2) is made of light metal and has a cross-sectional profile that delimits at least two chambers (5, 7, 9), at least one fastening device for releasably locking the flap (4) to the shaft rod (2), wherein at least one chamber (5) has a height (hk),which corresponds to at least 30% of the height (hs) of the shaft rod (2), and wherein the flap (4) of the side support (3) engages in said chamber (5) and fills it in the height direction (H) of the weaving shaft (1) at least in a region of the longitudinal extent of the weaving shaft (1).