Tow Ball Coupling Device with Wedge Mechanism for Wear Adaptation

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Solution Overview

Problem

Existing fixing devices for coupling balls have low clamping force and are ineffective in accommodating wear conditions, leading to reduced tightening effectiveness over time.

Innovation Solution

A fixing device with a rotatable arm and sliding wedge mechanism that allows for adjustable clamping force by translating the wedge on an inclined surface, enabling the device to adapt to varying wear states of the coupling ball, and is secured with a tension element like a screw or spring for locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a lever with rounded cam is used to bring half-shells together, then the device can be locked on the coupling ball, but the clamping force is low

Engineering Contradiction:
Improveclamping forceVSAvoiddevice structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent uses a spherical coupling ball as the core component, with two hemispherical half-shells that enclose it. The curved surfaces of the ball and shells create optimal contact areas, distributing clamping forces evenly across the spherical interface, thereby achieving high clamping force without requiring excessive mechanical leverage or complex structures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent employs a dynamic locking mechanism where the lever can rotate between locked and unlocked positions. The rounded cam profile on the lever transforms rotational motion into linear displacement of the half-shells, enabling the system to transition smoothly between states while maintaining high clamping force in the locked position without requiring a long lever arm.

Inventive Principle:
Principle #15Dynamics

2Force

If a long lever is used to obtain significant lever arm, then the clamping force increases, but the device size increases

Engineering Contradiction:
Improveclamping forceVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The spherical geometry of the coupling ball and hemispherical shells creates a compact enclosed space that maximizes clamping efficiency within a small volume. The curved contact surfaces concentrate forces effectively, eliminating the need for long lever arms while maintaining high clamping force in a compact device footprint.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The rotating lever with rounded cam provides a dynamic mechanical advantage that generates high clamping force through rotational motion rather than requiring a long static lever arm. This dynamic mechanism achieves force multiplication within a compact space, avoiding the volume penalty of traditional long-lever designs.

Inventive Principle:
Principle #15Dynamics

3Reliability

If fixed geometry half-shells are used, then the device structure is simple, but the tightening effectiveness is lost due to wear of the coupling ball

Engineering Contradiction:
Improvetightening effectivenessVSAvoidadaptability to wear conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs adjustable half-shells that can move relative to each other along the lever's rotational path. This dynamic adjustment capability allows the half-shells to compensate for wear on the coupling ball by repositioning themselves to maintain optimal contact and clamping force, thereby preserving tightening effectiveness despite wear while keeping the overall structure relatively simple.

Inventive Principle:
Principle #15Dynamics

4Force

If the wedge moves away from the center during tightening, then the clamping efficiency is improved, but the device bulk increases

Engineering Contradiction:
Improveclamping efficiencyVSAvoiddevice bulk
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The spherical coupling ball and hemispherical shells create a naturally compact geometry where the wedge can move outward from the center along the curved surface without significantly increasing device bulk. The spherical containment allows efficient force transmission while maintaining a compact overall form factor.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 device provides improved clamping efficiency and adaptability to different wear conditions, ensuring secure attachment of equipment to the coupling ball while maintaining a compact design.

Implementation Method 1

the wedge slides on an inclined face of the second part, said inclined face having an inclination with respect to a direction of rapprochement between the first and second parts

Methodology Applied
Scientific EffectInclined plane: Inclined Plane

Implementation Method 2

the at least one arm being configured to drive the wedge in translation so as to gradually bring the first and second pieces to the locked position

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 3

the wedge is preferably locked by a tension element such as a screw, a lever, and/or a spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3653408B1Device for attaching to a coupling ball
Publication Date: 2021.09.08 MGTS SA
  • EP3653408B1 patent drawingFigure 1A~1E
  • EP3653408B1 patent drawingFigure 2A~2F
  • EP3653408B1 patent drawingFigure 3A~3D

AI summary

The invention relates to a fastening device 1 for a tow ball 10 comprising first and second movable parts 11, 12 forming a jaw, and connected to each other by means of an articulated arm 21 fixed to the first part 11 and a sliding wedge 22 fixed to the second part 12. The articulated arm 21 can advantageously be actuated so as to translate the sliding wedge 22 along an inclined face 120 of the second part 12. The first and second parts 11, 12 are thus progressively brought together until the tow ball 10 is tightened. The wedge 22 can then be locked in a locked position.