Sewing Machine Presser Foot Cable Lifting Mechanism
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Solution Overview
Problem
Existing knee-operated lifting mechanisms for sewing machine presser feet are structurally complex due to the use of connecting rods, which complicates the transmission of motion and assembly.
Innovation Solution
A simplified knee-operated lifting mechanism using a cable and rotary member system, where the knee pushing plate controls a cable to rotate a drive shaft, which in turn moves the presser foot up and down, simplifying the structure and motion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If connecting rods are used to drive the presser foot up and down, then the presser foot can be controlled to move, but the structure becomes complicated
Solution Approach 1:
The patent extracts and removes the complex connecting rod transmission system from the sewing machine structure. Instead of using multiple connecting rods to transmit motion from the knee lever to the presser foot, the invention uses a simplified cable-pulley mechanism where the cable is routed through guides and pulleys to directly connect the knee lever with the presser foot assembly, eliminating unnecessary intermediate components
Solution Approach 2:
The patent introduces a cable as an intermediary element to transmit force and motion between the knee lever and the presser foot. The cable acts as a flexible mediator that can transmit tension forces efficiently while allowing for compact routing through the machine body, replacing the rigid and complex connecting rod arrangement
2Reliability
If connecting rods are used for transmission, then motion can be transmitted, but the assembly becomes complicated
Solution Approach 1:
The patent removes the multi-component connecting rod assembly and replaces it with a single cable element that performs the same motion transmission function. This extraction simplifies the manufacturing process as the cable can be easily installed and adjusted without requiring precise alignment of multiple rigid components
Solution Approach 2:
The patent employs a flexible cable instead of rigid connecting rods to transmit motion. The cable's flexibility allows it to be routed through the machine body along curved paths using guides and pulleys, simplifying the overall assembly and making it easier to manufacture and adjust compared to rigid rod mechanisms
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 mechanism effectively transmits motion through a cable system, simplifying the assembly and structure while allowing the presser foot to move up and down efficiently, enhancing usability and ease of assembly.
Implementation Method 1
a cable drivingly connected to the knee pushing plate; a rotary member pivotally mounted on the body of the sewing machine and including a cable fixing portion and a slide slot, wherein the cable is fixed to the cable fixing portion
Implementation Method 2
pushing the knee pushing plate controls the cable to pull the rotary member to rotate, then the drive shaft drives the presser-foot shaft to rotate
Implementation Method 3
the drive shaft drives the presser-foot shaft to rotate, consequently, the presser foot is driven to move upward
Data Source
AI summary
A knee operated lifting mechanism for a presser foot of a sewing machine is fixed on a body of the sewing machine, the body is provided with a presser-foot shaft, the knee operated lifting mechanism is drivingly connected to the presser-foot shaft, so as to consequently drive the presser foot to move up and down. The knee operated lifting mechanism includes a knee pushing device, a cable and a rotary member. The knee pushing device includes a knee pushing plate to be operated by a user. The cable is drivingly connected to the knee pushing plate to control the rotation of a drive shaft and the rotation of the presser-foot shaft as well, which consequently controls the upward and downward motion of the presser foot, and thus considerably simplifying the structure of the knee operated lifting mechanism.