Presser Foot Spreader Mechanism for Symmetrical Decorative Stitching
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Solution Overview
Problem
Existing sewing machines face issues with asymmetrical operation of spreaders due to differential power transmission, exposure of power transmission components leading to safety hazards, and inconvenience in attaching and detaching spreaders, which affect the appearance and usability during decorative stitching.
Innovation Solution
The sewing machine incorporates a presser foot with integrated spreader and spreader drive mechanism, a reciprocating motion conversion mechanism, and a link mechanism, minimizing exposure and ensuring symmetrical operation, safety, and ease of use by housing these components within the presser holder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the power transmission structure including the belt-shaped spreader is exposed behind the presser foot, then the spreader can be driven by the needle bar movement, but this leads to a risk of contact with operator's finger and adversely affects the appearance
Solution Approach 1:
The spreader and spreader drive mechanism are nested within the presser foot structure, which itself is part of the presser holder assembly. This hierarchical nesting conceals the power transmission components while maintaining their functional connectivity to the needle bar movement, eliminating safety hazards from exposed parts.
Solution Approach 2:
The presser foot acts as an enclosing shell that houses the spreader and its drive mechanism. This shell structure provides physical containment, preventing operator contact with moving parts while allowing the mechanism to function through the presser foot's structural integrity.
2Productivity
If the left and right spreaders have different power transmission paths, then the drive force can be distributed to each spreader, but this causes asymmetrical operation due to clearance or wear of moving parts
Solution Approach 1:
The invention intentionally uses asymmetric cam groove designs in the spreader bodies to achieve symmetric operational outcomes. The left and right spreaders have mirror-image cam grooves that, when engaged by their respective cam followers, ensure both spreaders rotate in opposite directions with identical amplitude and timing, compensating for any manufacturing clearances or wear through the geometric design.
Solution Approach 2:
The power transmission system is segmented into independent left and right pathways, each with its own cam groove and cam follower pair. This segmentation allows each spreader to be driven independently while maintaining symmetrical motion characteristics through carefully designed cam groove geometries that compensate for individual pathway variations.
3Object-affected harmful factors
If the spreader is removed when upper surface decorative stitching is not performed, then safety is improved, but the spreader may be lost and detaching and reattaching is bothersome
Solution Approach 1:
The spreader is merged with the presser foot structure, forming an integrated assembly where the spreader cannot be accidentally lost or misplaced. The presser foot serves as both the functional component for decorative stitching and the housing that secures the spreader, eliminating the need for separate attachment and detachment operations while maintaining safety through controlled engagement.
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 configuration allows for smooth, safe, and aesthetically pleasing decorative stitching by preventing contact with power transmission components, ensuring symmetrical operation, and accommodating thickness changes in fabrics, while providing a mechanism for easy power control and protection against excessive loads.
Implementation Method 1
a reciprocating motion conversion mechanism which is positioned above the throat plate and converts the rotation of an upper shaft into a linear reciprocating motion in a longitudinal direction
Implementation Method 2
a link mechanism which transmits a reciprocating motion produced by the reciprocating motion conversion mechanism to the spreader drive mechanism
Implementation Method 3
a cam follower which is provided on the slider and which rotates the spreader by sliding along the cam groove of the spreader as the slider moves
Data Source
AI summary
The sewing machine includes: a presser foot 1 which holds down a fabric on a throat plate 18; a presser holder 8 which supports the presser foot 1; a rotatable spreader 3 having a thread hole 14 through which sewing thread vertically passes; a spreader drive mechanism 4 which drives the rotation of the spreader 3; a reciprocating motion conversion mechanism 5 which converts the rotation of an upper shaft 7 into a linear reciprocating motion; and a link mechanism 6 which transmits the reciprocating motion produced by the reciprocating motion conversion mechanism 5 to the spreader drive mechanism 4. The spreader 3 and the spreader drive mechanism are both provided on the presser foot. The link 6 mechanism is provided on the presser holder 8.