Single-Side Collet Fastener for Ultra-Low Flush Grip Range

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Solution Overview

Problem

Existing fasteners lack an adjustable grip range and often have a protruding head, which is not suitable for applications requiring a low-profile, non-permanent joint that can be easily removed without damaging the workpieces.

Innovation Solution

The design of removable single side fasteners with a low-profile head and ultra-low stack height grip range, featuring a cylindrical housing body with longitudinal slots and a collet body that expands to clamp workpieces securely without protruding beyond the workpiece surface, utilizing a driven nut and compression spring for adjustable engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If existing fasteners are used to create non-permanent joints, then the workpieces can be removed or dismantled without damage, but the fastener head protrudes beyond the workpiece surface

Engineering Contradiction:
Improveremovability of workpiecesVSAvoidprofile height of fastener
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The fastener employs a nested structure where the collet body is received within the housing body, and the drive nut is received within the collet body. This nesting arrangement allows the fastener components to be compactly arranged along the longitudinal axis, enabling the fastener head to be recessed below the workpiece surface while maintaining full functionality for assembling and disassembling workpieces.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from a traditional protruding head design to a recessed head design by utilizing the longitudinal dimension of the fastener. The head portion is positioned to extend below the workpiece surface, effectively using the depth dimension to resolve the conflict between low profile requirement and functional requirement for workpiece removal.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If existing fasteners are used to join workpieces of various thicknesses, then adaptability is achieved, but the stack height is not minimized

Engineering Contradiction:
Improveadjustable grip rangeVSAvoidstack height
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The fastener incorporates a dynamic collet body that can expand and contract radially to grip workpieces of varying thicknesses. The collet body is biased by a spring to maintain constant engagement pressure, allowing it to adapt to different workpiece thicknesses while maintaining a compact stack height. The drive nut translates longitudinally to actuate the collet body expansion, providing adjustable grip range without increasing overall stack height.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the radial dimension parameter of the collet body to accommodate workpieces of various thicknesses. By translating the drive nut longitudinally, the collet body expands radially to grip thicker workpieces or contracts to grip thinner workpieces, providing adaptability while maintaining a low stack height profile.

Inventive Principle:
Principle #35Parameter changes

3Shape

If a low-profile fastener design is implemented, then the flush surface is achieved, but the grip range and adjustability are reduced

Engineering Contradiction:
Improveprofile heightVSAvoidgrip range
Core Design Contradiction:
ShapeVSAdaptability or versatility

Solution Approach 1:

The fastener is segmented into distinct functional components: housing body, collet body, drive nut, and spring. This segmentation allows the grip-range-adjusting mechanism (collet body expansion) to be decoupled from the profile height (head portion recessed below surface). The collet body can expand radially independent of the longitudinal profile, maintaining low stack height while providing full grip range adjustability.

Inventive Principle:
Principle #1Segmentation

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 secure clamping of workpieces with an ultra-low stack height, preventing damage and ensuring a flush surface, while allowing for easy assembly and disassembly without the need for tools, thus addressing the limitations of existing fasteners.

Implementation Method 1

a compression spring disposed within the housing body and in compressional contact with the collet body, the compression spring pushing the collet body and the driven nut forward

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the collet body expands to clamp workpieces securely

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3430275B1Removable, single side fastener with ultra-low stack height grip range, and methods for making and using the same
Publication Date: 2023.08.23 CENTRIX INC(US)
  • EP3430275B1 patent drawingFigure 1~2
  • EP3430275B1 patent drawingFigure 3
  • EP3430275B1 patent drawingFigure 4~5

AI summary

A removable single side fastener with ultra-low stake height grip range is disclosed. The fastener includes a housing body, a threaded screw, a drive nut and a collet body. The housing body has a housing head portion and a shank portion extending from the housing head portion with the shank portion forming at least two longitudinal slots. The threaded screw, disposed within the housing body, has a head portion rotatably confined within the housing head portion. The drive nut is rotationally coupled to the threaded screw and rotationally constrained relative to the housing body. The collet body has a pair of collet body legs converging inwardly. Each collet body leg has a toe which may extends radially outward beyond the longitudinal slots to compress work pieces against the housing head portion for fastening.