Tow Bar End Section Box Structure for Torsion and Weight

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Solution Overview

Problem

Existing tow bars face challenges in balancing strength and weight, particularly when handling high towing weights and torsional loads, which often requires thicker materials that increase weight and manufacturing complexity.

Innovation Solution

The implementation of a box structure in the end section of the tow bar assembly, featuring support elements and strategically positioned cut outs, improves load distribution and reduces the need for excessive material, thereby minimizing weight while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thicker and stronger material is used to compensate for torsion, then the strength and durability of the tow bar is improved, but the weight of the tow bar increases

Engineering Contradiction:
Improvestrength and durabilityVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent transitions from a traditional I-beam cross-section to a box-shaped cross-section. This dimensional change in the structural geometry provides superior torsional rigidity and strength distribution without requiring increased material thickness, thereby maintaining strength while reducing weight.

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

Solution Approach 2:

The patent optimizes the thickness parameters of the box structure walls and the dimensions of the box cross-section to achieve the required strength characteristics. By carefully selecting these geometric parameters, the design achieves adequate torsion resistance with thinner walls compared to traditional I-beam designs, reducing overall weight.

Inventive Principle:
Principle #35Parameter changes

2Force

If the tow bar is designed to handle high towing weights and high ride height, then the towing capacity is improved, but the torsion and structural complexity increase

Engineering Contradiction:
Improvetowing capacityVSAvoidstructural complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The box-shaped cross-section provides inherent structural rigidity that naturally resists torsional loads generated by high towing weights and extended lever arms. This geometric solution handles high forces without requiring additional complex reinforcement elements, brake brackets, or multiple support structures, thereby maintaining relatively simple construction.

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

3Weight of moving object

If lighter materials are used to reduce weight, then the fuel consumption is reduced, but the strength and ability to handle torsion is compromised

Engineering Contradiction:
ImproveweightVSAvoidstrength and torsion resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The box cross-section provides high torsional rigidity per unit of material compared to traditional I-beam sections. This efficient geometric configuration allows the use of thinner walls and lighter materials while maintaining adequate strength, achieving weight reduction without compromising torsion resistance.

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

Solution Approach 2:

The patent specifies that the box structure can be manufactured from various materials including steel, aluminum, or composite materials. This material flexibility allows selection of lighter materials such as aluminum or composites while the box geometry provides the necessary structural strength and torsion resistance.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3592579B2A tow bar assembly and a method for manufacturing a tow bar assembly
Publication Date: 2025.05.07 THULE TOWING SYST
  • EP3592579B2 patent drawingFigure 1~2
  • EP3592579B2 patent drawingFigure 3~4
  • EP3592579B2 patent drawingFigure 5

AI summary

The current disclosure relates to an end section (10) for a tow bar assembly (1) for a vehicle. The end section (10) comprises a vehicle connection portion (100) adapted to be connected to said vehicle and a tow bar connection portion (101) adapted to be connected to a tow bar (11). The end section (10) comprises a first support element (102) and a second support element (104) being connected to and extending between said vehicle connection portion (100) and said tow bar connection portion (101). The end section (10) further comprises a third support element (103) being connected to and extending between said first and said second support elements (102, 104) such that a box structure is formed. It further relates to a tow bar assembly (1) comprising at least one end section (10) and a method for manufacturing an end section (10).