Open Eye Needle Rotary Hook for Single-Thread Handstitch Control
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Solution Overview
Problem
Existing sewing machines struggle to form single-thread locked handstitches efficiently, particularly in the quasi-handstitch method, due to limitations in stitch length and inter-stitch pitch adjustment, and pose safety hazards during operation, while also failing to replicate the appearance and softness of traditional handstitches in quilting and patchwork.
Innovation Solution
A sewing machine design that uses an open eye needle with a thread capturing open eye, a rocking bobbin casing rotary hook, and a thread draw-out actuator to perform linear and elliptical motions, allowing for precise control over stitch formation on both the front and back surfaces of the fabric, enabling adjustable stitch length and inter-stitch pitch, and ensuring thread capture within the machine bed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a pinpoint stitch sewing machine uses a sewing needle with one thread pierced and an open eye needle with thread capturing open eye equipped laterally, then the stitch formation is automated, but the stitch length is limited to the distance between the sewing needle and the open eye needle
Solution Approach 1:
The invention divides the stitch formation process into two separate strokes: first stroke for forming handstitch on the front surface, and second stroke for forming locked stitch on the back surface. This segmentation allows independent control of stitch parameters in each stroke, enabling stitch length and inter-stitch pitch to be adjusted independently without being constrained by the distance between fixed needles.
Solution Approach 2:
The invention uses a single open eye needle that performs linear reciprocating motion vertically, with the thread capturing open eye positioned laterally. The needle's position and the open eye's orientation are dynamically controlled during the two-stroke process, allowing flexible adjustment of stitch length and inter-stitch pitch while maintaining automated operation.
2Reliability
If a quasi-handstitch sewing machine forms locked stitch in the lower side of the cloth, then the stitch is secure, but the worker cannot watch the sewing process and confirm the position of the pinpoint stitch
Solution Approach 1:
The invention uses periodic action by forming handstitches on the front surface alternately with locked stitches on the back surface through two-stroke cycles. This periodic formation of visible handstitches on the front surface allows the worker to monitor the sewing process and confirm stitch positions while maintaining the security of locked stitches on the back surface.
3Ease of manufacture
If a quasi-handstitch sewing machine uses a thread grapple hook and thread take-up lever arranged between the throat plate and rotary hook, then the thread can be manipulated, but the machine bed space becomes insufficient for concrete implementation
Solution Approach 1:
The invention extracts the thread manipulation functions from the traditional arrangement between throat plate and rotary hook. The thread draw-out actuator is positioned to draw out thread from the rotary hook, and the thread guide spreader guides the thread to the open eye needle, eliminating the need for complex arrangements in the limited machine bed space while maintaining effective thread manipulation.
4Ease of manufacture
If a quasi-handstitch sewing machine requires a thread draw-out actuator and thread guide spreader arranged in the limited space of the machine bed, then the thread can be guided properly, but the arrangement cannot be actualized concretely due to space constraints
Solution Approach 1:
The invention designs the thread draw-out actuator and thread guide spreader to perform multiple functions within the available space. The thread guide spreader not only guides the thread but also works in coordination with the open eye needle's lateral open eye positioning. This multi-functional design simplifies the overall arrangement and makes concrete implementation feasible within the machine bed space constraints.
Data Source
AI summary
A thread can be captured surely by the thread capturing open eye of a needle and a stitch can be formed in the space within a machine bed. A handstitch on the front surface of a fabric workpiece and a locked stitch on the back surface are formed as a skip-stitch set by cooperation of a open eye needle (13), a rotary hook (200) comprising a rocking bobbin casing (205) loaded in a rotative outer rotary hook (202), and a thread draw out actuator (401). In the first stroke of the open eye needle (13), a stitch length feed of the fabric workpiece for handstitch is performed by a feed dog (601). In the second stroke of the open eye needle (13), an inter-stitch pitch feed of fabric workpiece for inter-handstitch is performed by a feed dog (601).