Linear Motor Heald Frame Control for Dobby Loom Shedding
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Solution Overview
Problem
Existing shedding devices for weaving machines, particularly those with heald frames, lack flexibility in controlling shed positions and movement, limiting their ability to handle complex weft insertion patterns and energy efficiency at high speeds.
Innovation Solution
A control system for linear motors that allows precise control of the heald frame between upper and lower maximum positions at predetermined times, enabling flexible weft insertion and the creation of varied shed positions, including 'middle' positions, and the production of weft loops of different sizes and spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional shedding devices with fixed heald frames are used, then the structure is simple, but the flexibility in controlling shed positions and weft insertion patterns is limited
Solution Approach 1:
The patent applies dynamics by making the heald frames movable rather than fixed. Each heald frame can be independently positioned between upper and lower maximum positions at controlled times, enabling variable shed positions and patterns. This dynamic capability transforms the rigid, fixed-structure shedding device into a flexible system that can adapt to different weaving requirements through programmable motion control.
Solution Approach 2:
The patent replaces traditional mechanical shedding mechanisms with a control system that uses linear motors to actuate heald frames. This substitution of mechanical systems with motorized control enables precise, programmable positioning of heald frames at predetermined times, providing flexible control over shed positions without the complexity of traditional multi-component mechanical shedding devices.
2Productivity
If linear motors are used to control heald frame movement, then the weaving speed increases, but the power consumption increases
Solution Approach 1:
The patent applies periodic action by controlling the linear motors to operate intermittently rather than continuously. The control system activates linear motors only at specific moments when heald frames need to be repositioned between upper and lower maximum positions. This periodic actuation maintains high weaving speed capability while significantly reducing overall power consumption compared to continuous motor operation.
Solution Approach 2:
The control system performs preliminary action by pre-planning and coordinating the actuation of multiple linear motors. The controller determines optimal timing for each motor's operation based on the desired shed pattern, allowing motors to be activated in a coordinated sequence rather than simultaneously. This preliminary coordination reduces peak power demands while maintaining the ability to achieve high weaving speeds.
3Speed
If multiple linear motors are activated simultaneously, then the shed position changes quickly, but the power consumption peaks
Solution Approach 1:
The control system applies periodic action by distributing the actuation of multiple linear motors across different time intervals. Instead of activating all motors simultaneously to change shed positions, the controller sequences their activation in periodic cycles. This approach maintains the overall speed of shed position changes while avoiding peak power consumption associated with simultaneous motor activation.
Solution Approach 2:
The patent applies segmentation by dividing the actuation of multiple linear motors into separate, independent control events. Each linear motor is controlled individually with its own activation timing, allowing the system to segment the power demand across time. This segmentation enables rapid shed position changes through coordinated sequential actuation while preventing the accumulation of peak power demands that would occur with simultaneous activation.
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 solution enhances the flexibility and energy efficiency of weaving machines by allowing for precise control of heald frame movements, enabling more complex weft insertion patterns and reducing power consumption by decoupling the start times of linear motor movements, thus improving the protection of warp threads and increasing weaving speed.
Implementation Method 1
a linear motor is provided for each shaft which acts to advance the shaft in the direction of the arrow 2 and 4 in FIG. 1 along the guide 3 and 5
Data Source
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AI summary
In order to improve a dobby loom having a plurality of heddle frames, in particular having a changeover device for weft threads, according to the invention the heddle frames (4, 6, 8, 10) are each connected to a linear motor, such that by means of controlling the linear motor the heddle frame (4, 6, 8, 10) can be moved from an upper maximum position to a lower maximum position and vice versa. In one embodiment, the dobby loom has a plurality of warp thread presentation means, for example color control needles (18, 20), for the selective introduction of different weft threads (40, 42) into the warp shed and for changing the weft threads (40, 42). The loom comprises a control unit for controlling the linear motors, which control unit is designed to enable the control of a specified position of the heddle frame (4, 6, 8, 10) between the upper maximum position and the lower maximum position at a predetermined point in time. Said control unit has a sensor unit by means of which the position of each of the heddle frames (4, 6, 8, 10) can be detected continuously.