Sewing Machine Presser Mechanism Backlash Elimination
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Solution Overview
Problem
The existing sewing machines with cloth presser devices experience instability and noise due to a slight gap (backlash) between the cam groove and roller, affecting the stable operation of the presser member.
Innovation Solution
A sewing machine design incorporating a composite cam with inclined first and second cam surfaces, a forked member, and an urging device to stabilize the presser mechanism, ensuring consistent cloth holding and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single cam groove and roller engagement is used, then the structure is simple, but the operation of the presser member is unstable and noise occurs due to backlash
Solution Approach 1:
The single cam groove is divided into multiple cam grooves (first cam groove and second cam groove) that are engaged by a single roller. This segmentation allows the roller to be contacted by multiple cam surfaces simultaneously, distributing the load and eliminating backlash effects, thereby improving operational stability without significantly increasing overall structural complexity
Solution Approach 2:
Multiple cam grooves are merged into a single cam body structure, allowing the roller to engage with multiple cam surfaces at once. This combining approach maintains structural compactness while achieving stable presser member operation through the coordinated action of multiple cam surfaces
2Object-affected harmful factors
If a single cam groove is used, then the manufacturing is simple, but noise occurs due to the gap between cam groove and roller
Solution Approach 1:
The cam groove is segmented into multiple grooves with different orientations and positions. This segmentation ensures that the roller is always in contact with at least one cam surface, eliminating gaps and preventing noise generation during operation
Solution Approach 2:
The multiple cam grooves are pre-configured on the cam body at specific angles and positions. This preliminary arrangement ensures that regardless of the cam's rotational position, the roller maintains continuous contact with cam surfaces, preventing gap formation and noise before they can occur
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 provides a stable and noise-reduced operation of the presser member, enhancing the sewing machine's ability to hold down cloth effectively and maintain design freedom in the movement trajectory.
Implementation Method 1
The urging device is configured to constantly urge the main body member and the auxiliary member in a direction to clamp the cam member
Data Source
AI summary
A sewing machine includes a drive shaft rotated by a motor, a cam member fixed to the drive shaft and including a first cam and a second cam, a forked member including a main body member and an auxiliary member, an urging device, and a presser mechanism. At least one of a first cam surface of the first cam and a second cam surface of the second cam is inclined with respect to the drive shaft. The main body member and the auxiliary member are disposed to face each other such that the cam member is clamped between them. The urging device urges the main body member and the auxiliary member in a direction to clamp the cam member. The presser mechanism drives a presser member to hold a cloth, by swinging of the forked member caused by the rotation of the cam member.