Hybrid Lug Nut Drumhead Fastening for Easier Bolt Alignment

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Solution Overview

Problem

Existing drumhead fastening devices with movable lug nuts complicate the attachment process during drumhead replacement or manufacturing due to difficulty in aligning lug bolts with lug nuts, leading to cumbersome operations.

Innovation Solution

A drumhead fastening device with a combination of fixed and movable lug nuts, where at least one lug nut is immovably attached to the lug main body, allowing for easier alignment and attachment of lug bolts, while also preventing damage from dimensional inaccuracies and enhancing electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all lug nuts are made movable relative to lug main bodies, then damage from dimensional inaccuracies is prevented, but alignment and attachment of lug bolts becomes difficult and cumbersome

Engineering Contradiction:

Improveprevention of damage from dimensional inaccuraciesVSAvoidalignment and attachment of lug bolts

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies local quality by differentiating the functional characteristics of lug nuts at different positions. Specifically, lug nuts located at the diagonal ends of the shell are made movable to accommodate dimensional variations, while lug nuts at other positions are made fixed to provide stable alignment references. This localized differentiation resolves the contradiction by allowing movement only where necessary for tolerance compensation while maintaining stability where precision is needed for alignment.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the lug nuts into two distinct functional groups: movable lug nuts and fixed lug nuts. This segmentation allows the system to simultaneously achieve both tolerance accommodation (through movable lug nuts) and alignment stability (through fixed lug nuts), thereby resolving the contradiction between preventing damage from dimensional inaccuracies and facilitating easy lug bolt attachment.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If all lug nuts are made movable relative to lug main bodies, then adaptability to dimensional variations is improved, but the complexity of attaching lug bolts to all lugs increases

Engineering Contradiction:

Improveadaptability to dimensional variationsVSAvoidcomplexity of attaching lug bolts

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements local quality by assigning different mobility characteristics to lug nuts based on their positional requirements. Fixed lug nuts at diagonal ends provide stable attachment points that simplify the bolting process, while movable lug nuts at other positions provide adaptability to dimensional variations. This localized functional differentiation reduces overall attachment complexity while maintaining necessary adaptability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the lug nut population into fixed and movable categories, creating a hybrid system that balances adaptability with operational simplicity. This segmentation reduces device complexity by providing fixed reference points for alignment while maintaining movable capability where tolerance compensation is needed, thereby simplifying the overall attachment procedure compared to having all lug nuts movable.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If all lug nuts are made fixed to lug main bodies, then alignment precision is improved, but damage from dimensional inaccuracies cannot be prevented

Engineering Contradiction:

Improvealignment precision of lug boltsVSAvoidprevention of damage from dimensional inaccuracies

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by strategically placing fixed lug nuts at diagonal ends where precise alignment is most critical, while allowing other lug nuts to be movable to accommodate dimensional variations. This localized fixed-movable configuration simultaneously achieves both alignment precision and damage prevention from dimensional inaccuracies.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the lug nut system into fixed and movable components, creating a hybrid configuration that balances alignment precision with tolerance accommodation. The fixed lug nuts provide stable alignment references for precise lug bolt attachment, while movable lug nuts prevent damage by accommodating dimensional variations, thereby resolving the contradiction between alignment precision and damage prevention.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250378804A1Drumhead fastening device and drum

Publication Date: 2025.12.11 YAMAHA CORP

AI summary

A drumhead fastening device is used for attaching a drumhead to an open end of a shell. The drumhead fastening device includes a plurality of lugs. Each of the plurality of lugs includes a lug main body fixed to the shell and a lug nut attached to the lug main body. The drumhead fastening device further includes a plurality of lug bolts corresponding to the plurality of lugs, respectively. Each of the plurality of lug bolts is screw coupled with the lug nut of the corresponding lug. At least one lug of the plurality of lugs includes a fixed lug nut fixed immovably to the lug main body. At least one lug of the plurality of lugs includes a movable lug nut movably attached to the lug main body.