Sewing Machine Bobbin Thread Guide with Elastic Holding Member
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Solution Overview
Problem
In existing sewing machines, the bobbin thread becomes loose after being cut, leading to inappropriate interlocking with the needle thread, resulting in issues like skipped stitches and thread entanglement, which affects the smooth operation of the machine.
Innovation Solution
A sewing machine design that includes a bobbin thread guide member with a guide groove and a cutting blade, where a holding member, such as an elastic or rubber material, secures the cut bobbin thread to maintain tension, ensuring proper interlocking with the needle thread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bobbin thread is cut by a cutting blade, then the bobbin thread can be trimmed to appropriate length, but the bobbin thread becomes loose and loses tension
Solution Approach 1:
The holding member is positioned in advance within the guide groove to immediately grasp the bobbin thread at the moment of cutting. This preliminary positioning ensures that as soon as the cutting blade trims the thread, the holding member is already in place to maintain tension, preventing the thread from becoming loose before the sewing operation begins.
Solution Approach 2:
The holding member acts as an intermediary element between the cutting blade and the bobbin thread. It mediates the transition from the cutting action to the sewing operation by maintaining thread tension during the critical moment when the thread is most vulnerable to loosening, ensuring continuous tension stability.
2Ease of operation
If the bobbin thread is drawn out with slack onto the throat plate, then the thread can be easily positioned, but the thread cannot be properly interlocked with the needle thread
Solution Approach 1:
The guide groove provides a localized structured path that guides the bobbin thread from the slack state to the proper tension state. The groove's geometry creates different conditions at different locations: allowing easy positioning at the entrance while maintaining tension control near the cutting point, thus resolving the contradiction between ease of positioning and interlocking reliability.
3Reliability
If a holding member is added to maintain thread tension, then thread interlocking reliability improves, but the device complexity increases
Solution Approach 1:
The holding member is integrated with the guide groove structure, merging the tensioning function with the existing thread guidance pathway. This combination eliminates the need for separate complex tensioning mechanisms while achieving the reliability improvement, as the holding member becomes part of the natural thread path rather than an additional independent component.
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
The solution effectively maintains the tension of the bobbin thread after cutting, preventing loosening and ensuring reliable interlocking with the needle thread from the start of sewing, regardless of thread type, thus improving operational efficiency and reducing errors.
Implementation Method 1
a holding member, such as an elastic or rubber material, secures the cut bobbin thread to maintain tension
Data Source
AI summary
The sewing machine has: a base plate that has a guide slit for guiding a bobbin thread that is set on the bottom face side of the throat plate 1; and a bobbin thread guide member that has a guide groove for guiding the bobbin thread supplied from a bobbin and includes a cutting blade provide at the end position of the guide groove to cut the bobbin thread guided along the guide groove to an appropriate length. The bobbin thread guide member is secured to the base plate and has a holding member, which holds the end of the bobbin thread, in the guide groove, so as to maintain the state when the bobbin thread was cut.