Thin-Sheet Fastener Collar for Flush Torque-Out Resistance

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Solution Overview

Problem

Existing fastening systems, such as clinch and rivet technologies, face challenges in providing effective push-out and torque-out resistance on very thin sheets without increasing assembly thickness or distorting the material, especially in the electronics industry where thin panels are common.

Innovation Solution

A fastener design featuring a deformable shank collar with an undercut and cross-cut slots in the mating panel, allowing for snap-in engagement and subsequent deformation to enhance attachment forces, ensuring effective push-out and torque-out resistance even on panels as thin as 0.1 mm without adding thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If clinch fasteners are used to provide push-out and torque-out resistance, then attachment strength is improved, but additional sheet thickness is required which increases assembly thickness

Engineering Contradiction:

Improvepush-out and torque-out resistanceVSAvoidassembly thickness

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

The patent combines push-out resistance and torque-out resistance features into a single integrated collar structure. The collar includes both an undercut portion for push-out resistance and knurling for torque-out resistance, eliminating the need for separate features and reducing the thickness required compared to traditional clinch fasteners that require independent displacer, undercut, and knurl sections.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The collar serves multiple functions simultaneously: it provides push-out resistance through the undercut, torque-out resistance through knurling, and creates a flush appearance on the panel surface. This multi-functional design allows thin sheet applications to achieve comprehensive fastening performance without increasing assembly thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If rivet nuts are used to avoid material distortion in thin sheets, then material integrity is improved, but the fastener protrudes on both sides of the panel increasing assembly thickness

Engineering Contradiction:

Improvematerial integrityVSAvoidassembly thickness

Core Design Contradiction:

Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The collar is pre-formed with the undercut and knurling features before installation. During installation, the collar is deformed to engage with the panel, creating the fastening action. This preliminary formation allows the fastener to achieve its fastening function without requiring protrusion on both sides of the panel, as the deformation occurs within the panel thickness itself.

Inventive Principle:

Principle #10Preliminary action

3Strength

If standard clinching is used to provide attachment on thin sheets, then fastening capability is improved, but torque-out performance is poor

Engineering Contradiction:

Improveattachment capabilityVSAvoidtorque-out resistance

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The collar integrates both the undercut for push-out resistance and the knurling for torque-out resistance into a single continuous structure. This merging ensures that both functions work together synergistically, with the knurling features positioned to effectively engage with the panel material and prevent rotation, while the undercut provides the necessary push-out resistance.

Inventive Principle:

Principle #5Merging (Combining)

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 fastener provides enhanced push-out and torque-out resistance while maintaining a flush installation, overcoming limitations of traditional clinch and rivet systems by allowing secure attachment on very thin sheets without increasing panel thickness.

Implementation Method 1

The material of the fastener collar will also flow into the slots of the panel to prevent rotation

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

a punch and flat anvil are used to press the deformable collar of the fastener tightly against the prepared panel, capturing the panel rigidly between the collar and a base of the fastener

Methodology Applied

Scientific EffectMechanical compression: Compression

Data Source

PatentUS11428256B2Fastener for thin sheet material

Publication Date: 2022.08.30 PENN ENGINEERING & MANUFACTURING CORP

AI summary

A fastener for thin panels has a shank with a deformable collar which works in conjunction with a configured mating panel to produce enhanced attachment forces, especially in the case of very thin panels. The mating panel is prepared with a round mounting hole with cross-cut openings or slots. The panel is stamped into a conical section in a preparatory step before installation to provide the fastener with snap-in engagement prior to final pressing. The fastener shank has an undercut located immediately below the collar which is snapped into the prepared hole. Once snapped in, a punch and flat anvil are used to press the deformable band of the fastener tightly against the prepared panel, capturing the panel rigidly between the deformable band and a base of the fastener. During pressing, the material of the fastener collar will also flow into the slots of the panel to prevent rotation.