Vertical Full Rotation Shuttle Spring Biasing
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Solution Overview
Problem
The existing vertical full rotation shuttle in sewing machines experiences vibrations between the bobbin case and inner shuttle due to a clearance tolerance, leading to thread breakage and incidental looping caused by changes in thread tension during sewing operations.
Innovation Solution
A vertical full rotation shuttle design featuring a leaf spring member that biases the engaging strip within the engaging recess, preventing relative angular displacement between the bobbin case and inner shuttle, thereby reducing vibrations and maintaining consistent thread tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a clearance tolerance is provided between the engaging strip and engaging recess to allow removable mounting of the bobbin case, then the bobbin case can be easily removed and installed, but vibrations occur between the bobbin case and inner shuttle during sewing operations
Solution Approach 1:
The patent applies the dynamics principle by introducing a spring member that provides elastic compliance to the engagement system. The spring member allows the engaging strip to move dynamically within the engaging recess, absorbing vibrations while maintaining the removable mounting capability. This transforms the rigid clearance tolerance into a dynamic system that can adapt to operational forces.
Solution Approach 2:
The patent changes the physical state of the engagement system by introducing a spring member that alters the stiffness parameter of the connection between the bobbin case and inner shuttle. The spring member provides a controlled elastic deformation, changing the engagement from a rigid fixed-clearance system to a compliant system with optimized vibration characteristics.
2Ease of operation
If a clearance tolerance is provided between the engaging strip and engaging recess, then the bobbin case can be removably mounted, but thread breakage and incidental looping occur due to changes in thread tension
Solution Approach 1:
The spring member creates a dynamic engagement system that absorbs the shocks and vibrations caused by thread tension changes during sewing operations. This dynamic compliance prevents the rigid transmission of forces that would otherwise cause thread breakage and incidental looping, while preserving the removable mounting function.
Solution Approach 2:
By introducing the spring member, the system changes the mechanical impedance of the engagement interface. The spring provides a compliant connection that filters out high-frequency vibrations and shock loads, thereby protecting the thread from tension spikes that cause breakage and looping.
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 leaf spring member effectively restricts vibrations between the bobbin case and inner shuttle, preventing thread breakage and incidental looping by maintaining consistent thread tension during sewing operations.
Implementation Method 1
the spring member resiliently biases the engaging portion from an upstream side in the direction of rotation toward a downstream side in the direction of rotation by a spring force of the spring member
Data Source
Figure 1
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Figure 3
AI summary
In order to prevent occurrence of thread breakage and incident looping, a spring member (50) is provided in an engaging recess of an inner shuttle (3) to resiliently bias an engaging portion (27a) of an engaging strip (27) of a bobbin case (5) on a downstream side of a direction of rotation (A) so as to suppress rattling and vibrations of the bobbin case (5) against the inner shuttle (3).