Independent Lifting Drive Motor for Sewing Machine Material Feeder
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Solution Overview
Problem
Existing sewing machines lack flexibility in adjusting the intermittent lifting of the upper material slide during sewing operations, leading to potential misalignment and increased mechanical burden, noise, and reduced adaptability to changing sewing conditions.
Innovation Solution
Incorporating an independent lifting drive motor synchronized with the needle drive, allowing for precise control of the upper material slide's stroke and force, which is independent of the needle drive, enabling flexible setting options and reducing noise and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the upper material slide is intermittently lifted by a mechanically derived movement from the arm shaft, then the lifting can be synchronized with the needle drive, but the design effort is considerable and the stroke movement cannot be automatically adapted to changing sewing conditions
Solution Approach 1:
The lifting drive is separated from the needle drive into an independent motor-driven system. The upper material slide lifting function is segmented from the arm shaft mechanism, allowing independent control of lifting parameters (stroke length, lifting height, force) while maintaining synchronization through electronic control, thus improving adaptability without proportionally increasing overall system complexity
Solution Approach 2:
The lifting drive parameters are made dynamically adjustable during sewing operations. The stroke length, lifting height, and clamping force can be automatically adapted to changing sewing conditions through electronic control, transforming a static mechanically-derived system into a dynamic, programmable system that responds to varying requirements
2Ease of operation
If the upper material slide is lifted during sewing operations, then alignment adjustments can be made, but misalignment and relative displacement of material parts occur
Solution Approach 1:
The upper material slide is lifted during specific phases of the sewing cycle (e.g., during needle insertion or between stitches) when material displacement is minimal. This timing strategy allows alignment adjustments to be made preliminarily without causing significant misalignment, as the lifting occurs at strategically chosen moments when the material is least susceptible to relative displacement
3Device complexity
If the upper material slide is lowered without controlled deceleration, then the mechanical structure is simpler, but noise pollution increases and components are burdened
Solution Approach 1:
The lifting drive motor is programmed to decelerate the upper material slide before it reaches the lower material slide, providing a cushioning effect that prevents impact. This electronic control-based cushioning replaces the need for complex mechanical cushioning mechanisms, maintaining structural simplicity while eliminating noise and reducing component burden through controlled deceleration
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 precision of the upper material slide's movement, preventing misalignment, reducing noise and mechanical stress, and allowing for efficient operation at high sewing frequencies.
Implementation Method 1
A linear motor according to claim 2 leads to a particularly simple construction of the independent lifting drive of the upper material feeder.
Data Source
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AI summary
This sewing machine includes a lifter unit (26, 32) which is independent of the needle drive. It incorporates a lifter drive motor (26) fixed to the casing (2, 3, 4), working with a lift drive controller (30). The lifter drive is a linear motor (26). The controller supplies a sequence of currents to this motor, to cause raising and lowering. The currents supplied, are modulated in terms of their magnitudes and direction. The sequence is given in the detailed description. A first, forward acceleration current initiates raising of the upper material feeder (16). A reversed-direction braking current is then supplied. A reduced current is supplied in the forward direction, sufficient to hold the lifter. A second acceleration current is supplied in the reverse direction, to lower the upper material feeder. A lower current is then supplied in the reverse direction, for holding. During the cycle, following supply of the second acceleration current, an additional braking current may be supplied, in the forward direction. The lift drive motor works with a lifting rod carrying the upper feeder. The drive rod from the lift motor is connected to push and pull the lifting rod, with which it aligns. A carrier for the upper feeder is connected to a fixed support structure on the casing. This structure also has a separate feeder drive (24, 25) fixed to it. The arrangement allows the upper feeder to swing relative to the support structure (19) about an axis, between an upper lifted position and a lowered position. The drive controller is connected to the lift drive motor (26) and the needle drive. The needle rod position is detected from the needle drive. The lifter drive motor is controlled as a function of this position.