Sewing Machine Presser Foot Locking Mechanism
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Solution Overview
Problem
Conventional sewing machine presser devices require complex screw-based mechanisms for attaching and detaching presser feet, which can be cumbersome and time-consuming, especially when switching between different types of presser feet for various sewing modes.
Innovation Solution
A presser attaching mechanism with a locking mechanism on the presser bar that includes an operating member rotatable between locking and unlocking positions, allowing for easy attachment and detachment of presser feet or holders using a simple tool-free operation, utilizing a biasing member to secure the presser foot or holder in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw-based mechanism is used to attach presser feet to the presser bar, then the fixation is stable and reliable, but the operation becomes complex and time-consuming
Solution Approach 1:
The patent replaces the traditional screw-based mechanical fastening system with a bayonet-style locking mechanism featuring a locking pin and cam surface. This substitution eliminates the need for screws and screwdrivers, transforming the attachment process from a multi-step threading operation to a simple rotational locking action that achieves both stability and ease of use
Solution Approach 2:
The invention extracts and removes the screw fastening components from the presser foot attachment system. By eliminating screws, nuts, and threading mechanisms, the design achieves a cleaner, more direct attachment method where the presser foot is secured through a dedicated locking mechanism integrated into the presser bar itself
2Reliability
If a screw-based mechanism is used to attach presser feet, then the fixation is secure, but the time required for attachment and detachment increases
Solution Approach 1:
The patent replaces the time-consuming screw threading and tightening process with an instant rotational locking mechanism. The locking pin engages with the cam surface on a single rotational motion, providing secure fixation in seconds rather than requiring multiple steps of screw insertion, tightening, and verification
Solution Approach 2:
The locking pin is pre-positioned in the presser bar, and the cam surface is pre-formed on the presser foot. When the presser foot is inserted, the locking mechanism is already prepared to engage, eliminating the need for separate fastening actions and reducing attachment time to a simple insert-and-rotate motion
3Ease of operation
If a simple attachment mechanism is used, then the operation is easy, but the fixation stability may be insufficient
Solution Approach 1:
The patent replaces simple friction-based or snap-fit attachment mechanisms with a positive locking system using a locking pin and cam surface. This mechanism provides mechanical interlocking that ensures firm fixation while maintaining operational simplicity through a single rotational locking action
Solution Approach 2:
The cam surface incorporates a curved, inclined geometry that transforms the rotational motion of the locking pin into a directional locking force. This curved surface design allows the locking pin to engage smoothly and create a mechanical wedge effect that secures the presser foot firmly against the presser bar
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 quick and effortless switching between different presser feet, improving user convenience and reducing the need for intricate screw operations, while ensuring stable fixation during sewing.
Implementation Method 1
The locking mechanism has a biasing member which presses the operating member in a direction such that the mounting wall is pressed against the mount when the operating member is located at the locking position
Data Source
AI summary
A presser attaching mechanism for a sewing machine includes a locking mechanism switchable between a locking position where a presser foot or a presser holder is fixed to a presser bar and an unlocking position where the presser foot or the presser holder is released from the fixed state. The locking mechanism includes an operating member rotatable to the locking position and to the unlocking position. The presser bar is formed with a mount. The presser foot or the presser holder has a mounting wall and a mounting hole. The operating member is rotated from the unlocking position to the locking position, so that the operating member fixes the mounting wall to the mount. The locking mechanism has a biasing member which presses the operating member in a direction such that the mounting wall is pressed against the mount when the operating member is located at the locking position.