Sewing Machine Presser Foot Tool-Free Attachment Mechanism
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Solution Overview
Problem
Conventional presser foot attachment and detachment on sewing machines require screws and tools, making the process cumbersome and prone to errors due to vibration, especially when switching between normal stitching and embroidery.
Innovation Solution
A presser foot system with a slidable attachment shaft member and positioning shafts of different diameters, along with an elastic biasing member and a truncated conical knob, allows for one-touch attachment and detachment without screws or tools, ensuring correct alignment and preventing attachment errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fastening screw is used to attach and detach the presser foot, then the presser foot can be securely fixed to the presser bar, but the attachment and detachment process becomes cumbersome and requires dedicated tools
Solution Approach 1:
The invention extracts the screw fastening mechanism from the presser foot attachment system and replaces it with a bayonet-style coupling mechanism. The presser foot holder engages with the presser bar through a simple rotational locking action, eliminating the need for screws and dedicated fastening tools, thereby making attachment and detachment quick and tool-free while maintaining secure fixation.
Solution Approach 2:
Instead of using a screw that must be tightened and loosened, the invention inverts the approach by using a bayonet coupling where the presser foot holder is pushed onto the presser bar and locked through rotation. This inversion of the fastening mechanism allows for one-touch attachment and detachment without requiring the cyclic tightening and loosening actions of a screw.
2Reliability
If a fastening screw is used to attach the presser foot, then the presser foot can be securely fixed, but the screw may loosen due to vibration during operation
Solution Approach 1:
The invention removes the screw fastening system entirely and replaces it with a bayonet coupling mechanism that is inherently more resistant to vibration-induced loosening. The rotational locking engagement creates a rigid connection that maintains its integrity under vibrational loads, eliminating the problem of screws working loose during sewing machine operation.
3Reliability
If the fastening screw is tightened too tightly, then secure fixation is achieved, but a dedicated tool such as a driver is required for loosening
Solution Approach 1:
The invention extracts the screw and driver tool system from the attachment mechanism and replaces it with a bayonet coupling that can be engaged and disengaged by hand. The presser foot holder features a simple rotational locking action that requires no dedicated tools, eliminating the complexity of needing to locate and use a driver while maintaining secure fixation.
4Reliability
If conventional screw attachment is used, then the presser foot can be fixed to the presser bar, but switching between normal stitching and embroidery requires repeated fastening and loosening
Solution Approach 1:
The invention prepares the presser foot holder with a bayonet coupling mechanism that is pre-configured for quick engagement. The holder can be rapidly attached to or detached from the presser bar with a single rotational motion, allowing users to switch between normal stitching and embroidery modes instantly without the time-consuming process of repeatedly fastening and loosening screws.
Solution Approach 2:
The bayonet coupling mechanism introduces dynamic flexibility to the attachment system, allowing for rapid transitions between different presser foot configurations. The rotational locking and unlocking actions enable users to adapt quickly between stitching modes, making the system more responsive to changing operational requirements compared to static screw fastening.
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, tool-free, and error-proof attachment and detachment of the presser foot, improving operational ease and reducing the risk of misalignment during transitions between stitching modes.
Implementation Method 1
an elastic biasing member is formed as a coil spring
Data Source
AI summary
A presser foot for a sewing machine, is attached to a lower end of a presser bar to press a fabric during sewing, the presser bar being supported by the sewing machine so as to be slidable in an up-down direction. An attachment shaft member is provided in the presser bar so as to be slidable, the attachment shaft member attaching the presser foot so as to be detachable from the presser bar, and an attachment portion is provided in the presser foot so as to be fixed to the lower end of the presser bar by the attachment shaft member. The attachment shaft member includes a holding shaft portion that holds the attachment portion in the presser bar, and two positioning shaft portions having different shaft diameters smaller than that of the holding shaft portion.