Sewing Machine Feed Arm Stability via Mediator Shaft
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Solution Overview
Problem
Sewing machines face defects such as arm seizure and feed operation issues due to momentary forces generated during the feeding process, which affect the stability of the arm's position change transmission to the feed bracket.
Innovation Solution
The sewing machine incorporates a configuration with a lower shaft, feed dog, feed bracket, first and second arms, adjustment member, and urging member, where the second arm is supported to move along the shaft direction, allowing the urging force to act on it without easily transmitting to the second shaft and first arm, thereby stabilizing the engagement state and reducing the risk of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an urging member applies urging force to the arm to maintain engagement between the arm and feed cam, then the engagement state is stabilized, but moment of force is generated in the arm causing seizure or feed operation defects
Solution Approach 1:
The patent introduces a shaft as an intermediary component between the urging member and the arm. The shaft transmits the urging force from the urging member to the arm while allowing relative movement, thereby maintaining engagement stability without transmitting harmful moments directly to the arm. This mediator structure decouples the stabilizing function from the harmful moment generation.
Solution Approach 2:
The patent makes the arm movable relative to the shaft along the shaft's axial direction, transforming the static engagement into a dynamic system. The arm can move dynamically to accommodate the urging force while maintaining engagement, preventing the accumulation of harmful moments that would cause seizure or feed operation defects.
2Object-affected harmful factors
If the arm is made movable to reduce moment of force, then the risk of arm seizure is reduced, but the transmission stability of position change to feed bracket deteriorates
Solution Approach 1:
The shaft serves as a mediator that connects the movable arm to the fixed feed bracket. It allows the arm to move freely to reduce moment of force while ensuring that position changes are accurately transmitted to the feed bracket, maintaining transmission stability without causing arm seizure.
Solution Approach 2:
The patent creates a dynamic system where the arm moves relative to the shaft, but the shaft itself remains fixed and stable. This dynamic configuration allows the arm to adapt to forces while the shaft ensures stable transmission of position changes to the feed bracket, resolving the contradiction between mobility and stability.
3Reliability
If the urging force is applied to the arm along the shaft direction, then the engagement state is stabilized, but the force is transmitted to the shaft and first arm causing potential defects
Solution Approach 1:
The shaft acts as an intermediary that receives the urging force in the axial direction but is designed to handle this force without transmitting harmful moments to the first arm. The mediator structure allows the urging force to stabilize engagement while protecting the shaft and first arm from excessive loads that would cause durability issues.
Solution Approach 2:
The patent applies local quality by designing the shaft with specific properties to handle axial urging forces, while the arm is designed with mobility to reduce moment generation. Each component has optimized local characteristics - the shaft for force transmission and the arm for moment reduction - resolving the contradiction between engagement stability and component durability.
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 ensures a more stable transmission of the second arm's position change to the feed bracket, reducing the likelihood of arm seizure and feed operation defects, while maintaining a stable engagement state and simplifying the engagement mechanism.
Implementation Method 1
The urging member is configured to cause an urging force in an action direction along the shaft direction to act on the second arm
Data Source
AI summary
A sewing machine includes a lower shaft, a feed dog, a feed bracket, a first shaft, a first arm, a second shaft, a second arm, an engagement receiving portion, an adjustment member, and an urging member. The first arm is configured to support the feed bracket to be swingable around the first shaft. The second shaft is fixed to the first arm and extending in a shaft direction. The engagement receiving portion is configured to engage with the second arm to be movable with respect to the second arm. The adjustment member is configured to swing the first arm around the first shaft and to swing the feed dog supported by the feed bracket in both directions along a transport direction. The urging member is configured to cause an urging force in an action direction along the shaft direction to act on the second arm.