Sewing Machine Presser Device With Cam Actuation
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Solution Overview
Problem
Conventional intermittent presser devices for sewing machines produce collision noise due to the needle clamp colliding with the actuating lever, especially at increased sewing speeds, and have a large size that makes it difficult to reduce the device's dimensions.
Innovation Solution
A presser device with a first lever having a cloth pressing portion that pivots to press the workpiece cloth near the needle location and a second lever with an abutment portion that abuts the needlebar assembly, both biased by torsion coil springs to prevent collision noise and ensure reliable cloth pressing without increasing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the needle clamp abuts the actuating lever to activate the intermittent presser device, then the cloth pressing function is achieved, but collision noise is generated due to repeated impact
Solution Approach 1:
A cam member is introduced as an intermediary between the needle clamp and the actuating lever. The cam member converts the vertical reciprocating motion of the needle clamp into rotational motion of the actuating lever through controlled contact, eliminating direct impact collision while maintaining the intermittent presser activation function
Solution Approach 2:
The actuating lever is designed to rotate dynamically about a pivot point rather than moving linearly. This rotational motion allows smooth engagement and disengagement with the cam member, transforming the harmful impact collision into a controlled dynamic interaction that achieves the same functional result without noise
2Reliability
If the connecting pin is located away from the needle location to accommodate the actuating lever, then the intermittent presser mechanism functions, but the support size increases
Solution Approach 1:
The actuating lever is configured to rotate in a vertical plane rather than requiring horizontal space. By pivoting the lever vertically and using a cam member for actuation, the mechanism achieves the same intermittent presser function within a more compact horizontal footprint, effectively utilizing the vertical dimension to reduce overall support size
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 prevents collision noise and ensures reliable cloth pressing during sewing, preventing skip stitches while maintaining a compact device size.
Implementation Method 1
a first biasing member which biases the first lever so that the first lever is caused to pivot in such a direction that the cloth pressing portion becomes a cloth pressing position
Implementation Method 2
a second biasing member which biases the second lever so that the second lever is caused to pivot in such a direction that the abutment portion of the second lever abuts against the needlebar assembly
Data Source
AI summary
A presser device for a sewing machine includes a first lever having a cloth pressing portion which is swingably mounted on a presser foot, the cloth pressing portion being swung so as to be switchable between a cloth pressing position and a raised position, a second lever having a support portion where the second lever is pivotally supported on an upper part of the first lever and an abutment which is normally in abutment with a needlebar assembly moved up and down, a first biasing member which biases the first lever so that the first lever is caused to pivot in such a direction that the cloth pressing portion becomes a cloth pressing position, and a second biasing member which biases the second lever so that the second lever is caused to pivot in such a direction that the abutment of the second lever is abutted against the needlebar assembly.