Sewing Machine Presser Foot Decoupled From Needle Bar
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Solution Overview
Problem
Conventional free kilt stitching work pressing devices are noisy and limit the maximum rotation speed of sewing machines, making efficient stitching difficult, especially when working with thick materials due to their violent up and down movement and spring-activated design.
Innovation Solution
A free work pressing device with a slide shaft that is axially movable and not connected to the needle bar, featuring an adjust mechanism with a threaded slide shaft and screw member for vertical position adjustment, and a buffer to absorb impacts, allowing for high-speed operation without noise and easy handling of varying thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the slide shaft member is moved up and down by the needle bar that is driven to move up and down, then the work pressing foot is moved up and down in association with the up and down movement of the shaft member, but the up and down movement is rather violent and produces loud noises
Solution Approach 1:
The invention extracts the harmful connection between the needle bar and the work pressing foot by removing the pin that directly linked them. The work pressing foot is now moved only by the elastic member's restoring force, not by the violent needle bar movement, thereby eliminating the source of loud noises while maintaining the pressing function.
Solution Approach 2:
The invention applies beforehand cushioning by using an elastic member (spring) to provide a cushioned, controlled movement of the work pressing foot. The elastic member absorbs shocks and provides a smooth, noiseless operation compared to the direct mechanical coupling with the needle bar.
2Ease of operation
If the slide shaft member is moved up and down by the needle bar, then the work pressing foot is moved up and down, but it is problematical to set high the maximum rotation speed of sewing machine
Solution Approach 1:
The invention removes the pin connection that tied the work pressing mechanism to the needle bar's reciprocating motion. This extraction allows the sewing machine to operate at high speeds without the work pressing mechanism being constrained by the needle bar's movement cycle, thereby enabling higher maximum rotation speeds.
3Ease of operation
If the work pressing foot is normally pressed against the needle plate by means of a spring, then the work is stitched, but it is often difficult to stitch a rather thick work
Solution Approach 1:
The invention makes the work pressing foot dynamically adjustable by introducing a threaded adjust mechanism. The vertical position of the work pressing foot can be changed by rotating the adjust screw, allowing adaptation to different work thicknesses. This dynamic adjustment capability enables both thin and thick work to be stitched effectively.
Solution Approach 2:
The invention changes the parameter of the work pressing foot's vertical position through the threaded adjust mechanism. By rotating the adjust screw, the position parameter can be modified to accommodate varying work thicknesses, thereby improving adaptability to different work types including thick materials.
4Ease of operation
If the slide shaft member is connected to the needle holder of the needle bar, then the work pressing foot is moved up and down with the needle bar, but the structure becomes complex and produces violent movement
Solution Approach 1:
The invention extracts and removes the pin connection between the needle bar and the work pressing mechanism. This simplifies the overall structure by eliminating unnecessary components and their associated complexity, while the work pressing foot continues to function through the elastic member's restoring force.
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
Enables high-speed stitching without noise and facilitates easy handling of thick materials by allowing the work pressing foot to adjust vertically and absorb impacts, ensuring smooth operation and efficient stitching.
Implementation Method 1
an elastic member for normally pressing the slide shaft axially in the downward direction relative to the holding portion
Implementation Method 2
an adjust mechanism includes a buffer arranged on the upper end of the holding portion and between the adjust screw member and the holding portion
Data Source
AI summary
A free work pressing device for a sewing machine includes a holding portion for mounting the free work pressing device to the presser bar of sewing machine, a slide shaft supported by the holding portion and being slidingly movable in the axial direction, a work pressing foot secured to the lower end of the slide shaft, an elastic member for normally pressing the slide shaft axially in the downward direction relative to the holding portion, an adjust mechanism for adjusting the vertical position of the work pressing foot relative to the work which is to be stitched. The work pressing foot is smoothly movable as yielding up and down in dependence upon a variation in the thickness of the work against and under control of the elastic member.