Pivotable Trailer Coupling Hold-Down Device

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Solution Overview

Problem

Conventional trailer hitches with hold-down devices are prone to damage when subjected to extreme vertical loads and terrain angles, leading to unwanted contact and potential destruction during steep crossings or driving through troughs, particularly in agricultural or forestry sectors.

Innovation Solution

The trailer hitch design features a pivot axis aligned parallel to the rear axle of the towing vehicle, allowing the ball head and hold-down device to pivot, minimizing relative movement and preventing contact with the trailer-side coupling in extreme terrain, with the pivot axis intersecting the ball head and adjustable positioning to prevent swinging under tensile stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the hold-down device is made rigid and fixed in position, then the coupling socket is securely held against vertical movement under normal loads, but the device is prone to damage when subjected to extreme vertical loads and steep terrain angles

Engineering Contradiction:
Improvesecurity of coupling socketVSAvoiddamage resistance of hold-down device
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The hold-down device is made pivotable about a pivot axis that intersects the ball head, allowing it to dynamically adjust its position in response to varying loads and terrain angles. This dynamic capability enables the device to maintain secure coupling under normal conditions while avoiding damage during extreme maneuvers by pivoting away from contact with the coupling socket.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The orientation of the pivot axis is specifically designed to intersect the ball head, creating a geometric relationship that changes the contact parameters between the hold-down device and coupling socket based on the angle of inclination. This parameter change allows the device to transition from a contact state under normal loads to a non-contact state during steep crossings or trough driving.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the hold-down device is made pivotable to prevent damage, then damage resistance is improved, but the device complexity increases

Engineering Contradiction:
Improvedamage resistance of hold-down deviceVSAvoidstructural complexity of trailer coupling
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The pivotable hold-down device is integrated as a unified assembly with the ball head, where both components share a common pivot axis. This merging of functions reduces the number of separate mechanisms needed while achieving both secure coupling and damage resistance through the combined pivoting action of the ball head and hold-down device.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3666558B1Trailer coupling
Publication Date: 2021.11.24 PFANZELT MASCHENBAU
  • EP3666558B1 patent drawingFigure 1
  • EP3666558B1 patent drawingFigure 2
  • EP3666558B1 patent drawingFigure 3

AI summary

The trailer coupling (1) according to the invention comprises a mounting part (2) for attaching the trailer coupling to a towing vehicle, a ball head (3) and a retainer (4). The ball head (3) and the retainer (4) form a unit that is pivotably coupled to the mounting part (2) about a pivot axis (6), the pivot axis (6) being oriented such that it intersects the ball head (3).