Jacquard Loom Retaining Lever Air Gap Control
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Solution Overview
Problem
The precision and reliability of the selection device in a Jacquard type loom's shedding mechanism are limited by the air gap between the retaining lever and the electromagnet, affecting the magnetic attraction force and current supply control.
Innovation Solution
A mechanism with a ferromagnetic core electromagnet and a retaining lever that includes a non-magnetic body with a stop surface, allowing precise positioning of the external attraction surface relative to the electromagnet's polar surfaces, controlling the air gap and magnetic attraction force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the retaining lever is positioned close to the electromagnet to reduce the air gap, then the magnetic attraction force increases and selection precision improves, but the positioning accuracy and reproducibility of the air gap become difficult to control
Solution Approach 1:
A non-magnetic body is introduced as an intermediary element between the retaining lever and the electromagnet. This non-magnetic body includes a stop surface that limits the approach of the retaining lever, thereby precisely controlling the air gap distance. The non-magnetic material does not interfere with the magnetic field while providing mechanical positioning, resolving the contradiction between needing close proximity for strong magnetic attraction and needing precise control of the air gap for reproducibility.
2Force
If the air gap between the retaining lever and electromagnet is reduced, then the magnetic attraction force increases, but the control over the supply current and magnetic force becomes less precise
Solution Approach 1:
The non-magnetic body acts as a mechanical intermediary that pre-positions the retaining lever at a precise distance from the electromagnet. This mechanical positioning ensures a consistent and reproducible air gap, which in turn provides a stable baseline for controlling the magnetic attraction force through electrical current. The stop surface on the non-magnetic body serves as a mechanical reference that complements the electrical control system.
3Device complexity
If the retaining lever structure is simplified, then the device complexity decreases, but the ability to precisely control the air gap and magnetic attraction is compromised
Solution Approach 1:
The retaining lever assembly uses a composite structure combining magnetic and non-magnetic materials. The retaining lever itself remains relatively simple, but the addition of the non-magnetic body with its stop surface creates a composite system that achieves precise air gap control without significantly increasing overall structural complexity. The non-magnetic material is strategically placed only where needed for positioning, maintaining simplicity while adding precision.
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
Enhances the precision and reproducibility of the magnetic attraction between the retaining lever and electromagnet, improving the overall selection process in the Jacquard type loom.
Implementation Method 1
an electromagnet which includes a ferromagnetic core defining at least a first polar surface and at least a second polar surface
Implementation Method 2
a selection device comprising at least an electromagnet
Implementation Method 3
a ferromagnetic armature which interacts magnetically with the first and second pole surfaces to control the angular position of the retaining lever
Data Source
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AI summary
This crowd-forming mechanism includes at least one movable hook (X200) that can be held in position by a selection device comprising at least one electromagnet with a ferromagnetic core having at least one first and one second polar surface, these polar surfaces being offset from each other in the longitudinal direction. The selection device also includes a retaining lever (200) configured to retain the movable hook when it is in or near its top dead center position, the retaining lever being pivotable between a position away from the electromagnet and a position pressed against the electromagnet.The retaining lever (200) includes a ferromagnetic armature (202) that interacts magnetically with the first and second pole surfaces to control the angular position of the retaining lever about the axis of oscillation. This armature includes an external attraction surface (S208) that is opposite the second pole surface when the retaining lever is in the position pressed against the electromagnet, and a non-magnetic body (204) integral with the armature (202). The non-magnetic body (204) of the retaining lever (200) includes at least one stop surface (S204), which is adjacent to the external attraction surface (S208), distant from the electromagnet when the retaining lever is in its position away from the electromagnet, and in contact with the electromagnet when the retaining lever is in its position pressed against the electromagnet.Furthermore, in the position where the retaining lever is pressed against the electromagnet, the external attraction surface (S208) is distant from the second polar surface.