Sewing Machine Needle Bar Swing Synchronization
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Solution Overview
Problem
Conventional sewing machines face difficulties in forming wide zig-zag or pattern stitches due to synchronization issues between the needle and shuttle, limiting the range of needle bar swing and restricting the complexity of sewing patterns.
Innovation Solution
A sewing machine design that includes a needle-bar swing unit, a first output generating unit, a link unit, and an output axis moving unit, which adjusts the motion trajectory of the needle to maintain synchronization with the shuttle, allowing for increased needle bar swing width without structural modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the needle bar swings from side to side to form wide zig-zag or pattern stitches, then the swing width increases, but the synchronization between the needle and shuttle deteriorates
Solution Approach 1:
The patent applies dynamics by making the needle bar's motion trajectory adjustable rather than fixed. The control unit dynamically modifies the needle bar's path based on swing width requirements, allowing the system to adapt its motion characteristics. This enables wide zig-zag sewing while maintaining proper needle-shuttle synchronization through real-time motion adjustment.
Solution Approach 2:
The patent changes the motion parameters of the needle bar, specifically its trajectory and timing, in response to different swing width requirements. By adjusting these parameters dynamically, the system maintains optimal needle-shuttle interaction even when operating at extended swing widths that would normally cause synchronization loss.
2Adaptability or versatility
If the needle bar swing width is increased beyond the margin range, then more sewing patterns become possible, but the ability to form stitches deteriorates
Solution Approach 1:
The control unit dynamically adjusts the needle bar's motion trajectory based on the selected swing width and sewing pattern requirements. This dynamic adaptation allows the system to maintain reliable stitch formation across a wide range of sewing patterns, from simple straight stitches to complex zig-zag and pattern stitches, by optimizing the needle's path and timing for each specific operation.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor the needle bar position and swing width, allowing the control unit to make real-time adjustments to maintain proper synchronization and stitch formation. This feedback loop ensures that even when operating at the limits of swing width capability, the system can adapt to preserve stitch quality and reliability.
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
Enables the formation of appropriate stitches even with wider swing widths, providing more sewing pattern options by correcting needle displacement and maintaining optimal positional relationships between the needle and shuttle, thus overcoming the limitations of conventional machines.
Implementation Method 1
moves, relative to a cloth, a needle attached to a needle bar up and down based on drive force from a rotating upper shaft
Implementation Method 2
a needle-bar swing unit swinging the needle bar in an orthogonal direction to a cloth feeding direction
Implementation Method 3
the link unit changes an inclination in accordance with a movement of the output axis, and moves up and down the needle bar in substantially parallel with the output axis while maintaining the inclination
Data Source
AI summary
A sewing machine moves a needle up and down relative to a cloth based on drive force from a rotating upper shaft to form a stitch. A first output generating unit reciprocates a first output point along an output axis so as to convert the rotational motion of the upper shaft into a linear motion. An assist rod that serves as a connection portion links the first output point with a needle bar. A needle-bar swing unit swings the needle bar. An output shaft moving unit moves a guide that is the output axis in a cloth feeding direction in accordance with the motion of the needle-bar swing unit. The assist rod changes the inclination in accordance with the movement of the output axis, and reciprocates the needle bar in substantially parallel with the output axis while maintaining the inclination.