Rotatable Coupling Head Brake for Trailer Hitch Play

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Solution Overview

Problem

Existing detachable tow hitches face challenges in maintaining driving comfort under high loads and negative tow ball pressure, as the locking pin's self-releasability can lead to play in the three-point suspension, causing discomfort due to potential detachment and increased resistance.

Innovation Solution

A coupling assembly with a rotatably connected coupling head that increases friction through contact with the longitudinal bore's walls, utilizing a rotary hinge and spring elements to maintain a locked position even under high loads, ensuring a secure and comfortable towing experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the locking pin is designed to be self-releasing, then the coupling assembly can be easily uncoupled, but under high loads the locking pin may become slightly detached causing play and reducing driving comfort

Engineering Contradiction:
Improveease of uncouplingVSAvoidstability under load
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The coupling head is designed to be rotatable with respect to the coupling rod, allowing it to dynamically adjust its position. Under normal conditions, the coupling head remains in a neutral position, but under negative ball pressure, it can rotate to contact the wall sections of the longitudinal bore, creating additional friction to counteract reverse motion and maintain reliability while preserving ease of operation.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the coupling head is fixed to the coupling rod, then the connection is rigid and stable, but the coupling head cannot independently contact the longitudinal bore walls to increase friction under external forces

Engineering Contradiction:
Improverigid connectionVSAvoidfriction force under load
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The coupling head is made rotatable relative to the coupling rod through a rotary hinge, enabling it to dynamically respond to external forces. When negative ball pressure occurs, the coupling head can rotate to press against the wall sections of the longitudinal bore, generating additional friction force to counteract reverse motion, thus maintaining both stability and increased force resistance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotary hinge acts as an intermediary mechanism between the coupling rod and the coupling head. It allows the coupling head to move independently when needed to contact the longitudinal bore walls, while still maintaining a form-closed connection through the hinge pin, thus enabling both rigid connection and independent movement capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If the coupling head contacts the longitudinal bore walls through rotation, then friction increases to counteract reverse motion, but the device complexity increases due to the rotary hinge mechanism

Engineering Contradiction:
Improvefriction forceVSAvoidrotary hinge mechanism
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The rotary hinge mechanism is designed to be self-actuating. Under normal conditions, the coupling head remains in its neutral position without requiring external control. When negative ball pressure occurs, the coupling head automatically rotates to contact the wall sections of the longitudinal bore, utilizing the applied force itself to activate the friction-maintaining mechanism, thus reducing the need for additional control systems and minimizing device complexity.

Inventive Principle:
Principle #25Self-service

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 solution effectively counteracts reverse motion of the coupling head, maintaining a secure connection and enhancing driving comfort by increasing friction and preventing play, even under increased external forces such as negative ball pressure.

Implementation Method 1

The part of the coupling head that is situated within the longitudinal bore is able to contact the wall sections of the longitudinal bore for on the basis of friction counteracting a reverse motion of the coupling head out of the locking position

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a spring element arranged in the coupling head and having a retaining force exerted in the insertion direction A on the coupling head

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP1935675B1Coupling assembly with coupling head brake
Publication Date: 2011.03.09 THULE TOWING SYST
  • EP1935675B1 patent drawingFigure 1
  • EP1935675B1 patent drawingFigure 2A
  • EP1935675B1 patent drawingFigure 2B

AI summary

Coupling assembly (1) for a vehicle, comprising a first coupling member provided with a connection part for/towards a trailer or an accessory, and a second coupling member attachable to the vehicle with which second coupling member the first coupling member can be detachably coupled in a coupling position for connection to the vehicle, wherein the first coupling member comprises a rod-shaped insertion end (7) having first coupling means and having second coupling means that are offset in insertion direction, and the second coupling member comprises a socket having an access opening for accommodation of the insertion end, third coupling means for cooperation with the first coupling means, and fourth coupling means for cooperation with the second coupling means, wherein in the first coupling member comprises a coupling rod (10) and a coupling head (11) connected to the coupling rod, which extend in axial direction through a longitudinal bore in the insertion end, wherein the coupling rod (10) and the coupling head are movable in the axial direction with respect to the longitudinal bore up to a locking position for in the coupling position keeping the coupling means in coupling cooperation, wherein the coupling head (11) is rotatable with respect to the coupling rod for rotation of a part of the coupling head situated within the longitudinal bore when the coupling head is in the locking position.