Sewing Machine Thread Cutter with Dual Seizing Assemblies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thread cutters for sewing machines leave excessive needle and bobbin threads, leading to thread entanglement and increased manual cutting requirements, due to the fixed blade location being farther from the needle hole, resulting in inefficient thread cutting.
Innovation Solution
A thread cutter design with a first thread seizing assembly that seizes threads and a second thread seizing assembly cooperating with a cutting blade located closer to the needle hole, reducing remaining threads by cutting them during backward movement, supported by a thread cutting frame with an elongated groove for reciprocal movement and driven by a stepping motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fixed blade is mounted on the proximal end side of the thread seizing assembly, then the construction is simplified, but the remaining amount of threads at the workpiece cloth side increases
Solution Approach 1:
The thread cutting function is divided into two stages: first thread seizing assembly for initial thread capture, and second thread seizing assembly for final thread cutting. This segmentation allows the cutting blade to be positioned closer to the needle hole while maintaining operational simplicity through coordinated movement of two assembling units.
Solution Approach 2:
The patent introduces a lateral displacement dimension by positioning the second thread seizing assembly at a different location than the first. The cutting blade is arranged at a position closer to the needle hole, creating a multi-dimensional thread cutting path that reduces remaining threads without complicating the overall structure.
2Device complexity
If the fixed blade is mounted on the proximal end side of the thread seizing assembly, then the device structure is simplified, but the remaining amount of needle thread at the needle side increases
Solution Approach 1:
The thread cutting operation is segmented into two coordinated phases involving two thread seizing assemblies. The first assembly captures threads initially, then the second assembly positioned closer to the needle hole completes the cutting, thereby reducing remaining needle thread without increasing structural complexity.
Solution Approach 2:
The first thread seizing assembly performs preliminary thread capture and positioning before the second assembly executes the final cutting action. This preliminary action ensures threads are properly positioned for efficient cutting closer to the needle hole, reducing remaining thread length.
3Reliability
If extra threads remain at the workpiece cloth and needle sides, then thread entanglement may occur, but manual cutting is required
Solution Approach 1:
The dual thread seizing assembly system performs self-service thread cutting automatically during the sewing operation. The coordinated movement of both assemblies ensures complete thread cutting closer to the needle hole, eliminating the need for manual thread trimming and preventing entanglement without requiring additional operator intervention.
Data Source
AI summary
A thread cutter for a sewing machine includes a first thread seizing assembly reciprocally movable and having a distal end with a first thread seizing portion, a second thread seizing assembly seizing needle and bobbin threads both having been seized by the first assembly during a backward movement of reciprocation of the first assembly, cutting the needle and bobbin threads in cooperation with a cutting blade, and a thread cutting frame supporting the first assembly and formed with a single elongated groove supporting the first assembly so that the first assembly is movable. The elongated groove includes a linear proximal end groove, an oblique portion, and a main groove and being shaped such that the proximal end groove is translated slightly forward through the oblique portion. When moved backward in the reciprocation, the first assembly is swung so that the first thread seizing portion comes close to the second assembly.