Double-Wedge Cable Chuck for Compact High-Retention Fittings

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Solution Overview

Problem

Conventional cable fittings with single wedge chucks are lengthy, expensive to manufacture, and difficult to mount in tight spaces, while reducing their length compromises the alignment and retention properties due to increased taper angles.

Innovation Solution

A cable fitting design featuring a gland nut, body, and chuck with sloped surfaces that apply compressive forces to inwardly deform the chuck segments, forming a dual wedge mechanism with a bushing for enhanced cable retention and reduced length, utilizing materials like nylon and thermoplastic rubber for flexibility and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional single wedge chuck design is used, then cable retention is achieved, but fitting length becomes excessive and manufacturing cost increases

Engineering Contradiction:
Improvecable retention forceVSAvoidfitting length
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The chuck is divided into multiple segments (typically three) that can independently deform inward under compressive force. This segmentation allows the cable retention function to be distributed across multiple points of contact, achieving strong cable grip in a more compact configuration without requiring a long single-wedge structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-wedge axial compression mechanism to a multi-segment radial deformation mechanism. The segments deform radially inward toward the central axis, creating cable retention through circumferential compression rather than relying on a long axial wedge geometry, thus reducing fitting length while maintaining retention strength

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

2Strength

If conventional single wedge chuck design is used, then cable retention is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvecable retention forceVSAvoidfitting structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The chuck is divided into multiple segments (typically three) that can independently deform inward under compressive force. This segmentation allows the cable retention function to be distributed across multiple points of contact, achieving strong cable grip in a more compact configuration without requiring a long single-wedge structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-wedge axial compression mechanism to a multi-segment radial deformation mechanism. The segments deform radially inward toward the central axis, creating cable retention through circumferential compression rather than relying on a long axial wedge geometry, thus reducing fitting length while maintaining retention strength

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

3Ease of operation

If fitting length is reduced to mount in tight spaces, then ease of installation improves, but alignment and retention properties deteriorate due to increased taper angles

Engineering Contradiction:
Improveease of mountingVSAvoidalignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The chuck segments are designed to be dynamically deformable under compressive force, transitioning from a relaxed state to a compressed state that engages the cable. This dynamic deformation allows the segments to self-align with the cable and bushing during installation, maintaining alignment precision even in compact configurations where static rigid structures would fail

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameters of the chuck segments, using smaller taper angles (e.g., 15-30 degrees) compared to conventional designs. This parameter change allows the segments to achieve effective cable engagement in a shorter axial distance, improving ease of mounting while preserving alignment precision through controlled radial deformation

Inventive Principle:
Principle #35Parameter changes

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 dual wedge mechanism provides increased cable retention force with reduced fitting length, improving alignment and ease of mounting in tight spaces, while maintaining predictable alignment behavior and cost-effectiveness.

Implementation Method 1

the first sloped surface is configured to apply a first compressive force to the distal end tapered surfaces, and the second sloped surface is configured to apply a second compressive force to the proximal end tapered surfaces

Methodology Applied
Scientific EffectCompressive force: Compression

Implementation Method 2

the compressive forces cause inward deformation of the chuck to secure the cable within the axial pathway

Methodology Applied
Scientific EffectMechanical deformation: Deformation

Implementation Method 3

A cable fitting design featuring a gland nut, body, and chuck with sloped surfaces that apply compressive forces to inwardly deform the chuck segments, forming a dual wedge mechanism

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Implementation Method 4

the first sloped surface is configured to apply a first compressive force to the distal end tapered surfaces, and the second sloped surface is configured to apply a second compressive force to the proximal end tapered surfaces

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 5

The bushing may comprise a thermoplastic rubber material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 6

utilizing materials like nylon and thermoplastic rubber for flexibility and sealing

Methodology Applied
Scientific EffectSealing: Adhesive

Data Source

PatentEP2760092B1Electrical cable restrain device using a double wedge chuck
Publication Date: 2016.06.15 THOMAS & BETTS INTERNATIONAL INC
  • EP2760092B1 patent drawingFigure 1
  • EP2760092B1 patent drawingFigure 2
  • EP2760092B1 patent drawingFigure 3

AI summary

A cable fitting includes a gland nut, a body, and a chuck. The gland nut includes first threads, an axial gland bore, and a first sloped surface along a portion of the axial gland bore. The body includes second threads to receive the first threads, an axial body bore, and a second sloped surface along a portion of the axial body bore. The chuck includes multiple segments joined in a hinged fashion to create a ring. Each of the multiple segments includes a distal end tapered surface and a proximal end tapered surface. When the gland nut is advanced onto the body, the first sloped surface applies a first compressive force to the distal end tapered surfaces, and the second sloped surface applies a second compressive force to the proximal end tapered surfaces. The compressive forces cause inward deformation of the chuck to secure a cable within an axial pathway.