Sewing Machine Projector for Stitch Positioning
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Solution Overview
Problem
Conventional sewing machines face difficulties in accurately positioning the edge of a workpiece cloth or previously formed stitches relative to the presser foot, leading to challenges in maintaining a consistent stitch interval, especially for curved edges, and require multiple presser feet for varying stitch intervals, which is cumbersome and costly.
Innovation Solution
A workpiece cloth positioning guide device that projects a sewing reference mark with a circle centered on the needle drop point onto the workpiece cloth, allowing for precise positioning and adjustable stitch intervals by varying the size of the circle using a telescopic projector and lens system, enabling easy alignment and feeding of the cloth for consistent stitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a presser foot is used for positioning the workpiece cloth edge or previously formed stitches, then the stitch interval can be maintained at a predetermined distance, but the presser foot stands in the way of the operator's view and makes it difficult to position the cloth accurately
Solution Approach 1:
The patent uses a projector to create a visual copy (reference mark) of the positioning information on the workpiece cloth surface. Instead of relying on the physical presser foot as the reference, the system projects a mark that represents the desired stitch position, allowing the operator to see and align the cloth edge or previous stitches with the projected reference without the presser foot obstructing the view.
Solution Approach 2:
The patent replaces the mechanical positioning reference (presser foot) with an optical system (projector). The mechanical presser foot is substituted by a light-based projection system that displays positioning information optically on the workpiece surface, eliminating the visual obstruction caused by the physical presser foot while maintaining positioning accuracy.
2Adaptability or versatility
If multiple presser feet with different sizes are provided to change stitch intervals, then various stitch intervals can be achieved, but the device complexity increases and changing presser feet is extremely troublesome
Solution Approach 1:
The patent makes the positioning reference dynamic and adjustable through the projector system. Instead of having fixed, static presser feet with predetermined sizes, the projection system can dynamically display reference marks corresponding to different stitch intervals. The operator can change stitch intervals by adjusting the projection parameters rather than physically changing components, making the system adaptable without increasing mechanical complexity.
Solution Approach 2:
The patent creates a universal positioning system where a single projector device can perform the function of multiple presser feet. The projection system is multi-functional, capable of displaying reference marks for various stitch intervals and positioning requirements using one device, eliminating the need for multiple specialized presser feet.
3Ease of operation
If a projector projects a linear sewing reference line onto the sewing bed, then the edge of the workpiece cloth can be positioned, but it has difficulty forming stitches with predetermined intervals on workpiece cloth including curved edges
Solution Approach 1:
The patent adapts the projection system to display curved reference marks that match the curvature of the workpiece edges. Instead of only linear reference lines, the projector can display circular or curved reference patterns that conform to curved workpiece geometries, enabling accurate stitch interval maintenance on curved edges by providing visually guided curved positioning references.
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 reliable and flexible formation of stitches at desired intervals on variously shaped workpieces, including curved ones, without the need for multiple presser feet, improving operational ease and reducing costs by allowing precise control over stitch spacing.
Implementation Method 1
a transmission part provided in a lengthwise middle portion of the cylindrical body and formed with a mark forming pattern for forming the sewing reference mark
Implementation Method 2
a projector lens provided in the lower end of the cylindrical body
Data Source
AI summary
A workpiece cloth positioning guide device for a sewing machine includes a projector which projects a sewing reference mark onto an upper side of workpiece cloth placed on a sewing bed of the sewing machine. The projector includes a telescopic cylindrical body having an upper end provided with the light source and a lower end, a transmission part provided in a lengthwise middle portion of the cylindrical body and formed with a mark forming pattern for forming the sewing reference mark, a projector lens provided in the lower end of the cylindrical body, and a projector lens elevating unit which raises and lowers the projector lens, and a mark size setting unit which sets a size of the circle of the sewing reference mark to a desired size.