Rigid Trailer Drawbar Adjustment for Coupling Height Mismatch

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Solution Overview

Problem

Trailer coupling height variability due to non-optimal loading or vehicle adjustments leads to non-horizontal orientation, causing overloading, reduced braking efficiency, and uneven tire wear, especially in trailers with tandem or tridem axles, and is costly to address with pivotally adjustable drawbars.

Innovation Solution

A rigid drawbar with immovable but releasable attachment to the chassis at multiple positions, allowing adjustable angle settings to match the towing vehicle's coupling height, using convex and concave surfaces with bolt passages for secure attachment, enabling simple and cost-effective height adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pivotally adjustable drawbar is used to make coupling height adjustable, then the adaptability to different towing vehicle heights is improved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvecoupling height adjustabilityVSAvoiddrawbar structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The drawbar is designed with a telescopic structure that allows it to extend and retract, dynamically adjusting its length to compensate for coupling height variations. This dynamic length adjustment replaces the need for complex pivotal mechanisms while achieving the same adaptability goal.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The drawbar is divided into multiple segments or telescopic sections that can extend and retract relative to each other. This segmentation allows the drawbar to achieve variable length in a compact manner, reducing overall structural complexity compared to a single-piece pivotal drawbar.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a pivotally adjustable drawbar is used to accommodate coupling height variations, then the adaptability is improved, but the strength and stability of the drawbar decrease due to the hinge mechanism

Engineering Contradiction:
Improvecoupling height adjustabilityVSAvoiddrawbar structural strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The telescopic drawbar maintains a rigid, hinge-free structure that preserves full structural strength while achieving height adjustment through length variation. The telescopic sections are designed to maintain structural integrity throughout the adjustment range, avoiding the weakness inherent in pivotal connections.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The telescopic sections incorporate curved or angled geometries that optimize force distribution and structural strength while enabling the extension and retraction motion. This curved design allows the drawbar to maintain high strength-to-weight ratio without requiring additional support hinges.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If the coupling height is not adjusted to match the towing vehicle, then the device complexity remains low, but the reliability of the connection and performance of the trailer decrease due to overloading and uneven tire wear

Engineering Contradiction:
Improvedrawbar structure simplicityVSAvoidconnection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The telescopic drawbar incorporates self-adjusting mechanisms that automatically compensate for coupling height variations without requiring external intervention or complex control systems. The drawbar length adjusts in response to the coupling height difference, maintaining reliable connection conditions automatically.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The drawbar length parameter is made variable to adapt to different coupling heights, allowing the system to maintain optimal connection geometry across various towing vehicle configurations. This parameter change ensures reliable force transmission and prevents overloading while keeping the overall structure relatively simple.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3838633B1trailer
Publication Date: 2023.11.22 BCW NV
  • EP3838633B1 patent drawingFigure 1
  • EP3838633B1 patent drawingFigure 2~3
  • EP3838633B1 patent drawingFigure 4

AI summary

Trailer (1) comprising a rigid drawbar (6) and a chassis (3) extending in a longitudinal direction (L), wherein the drawbar (6) extends from its rear side to its front side in a first direction (K), wherein the drawbar (6) and the chassis (3) are adapted to immovably and releasably attach the drawbar (6) to the chassis (3) in two or more different attachment positions, wherein in said different attachment positions, the angle (α) between the first direction (K) and the longitudinal direction (L) is different, wherein the drawbar (6) and the chassis (3) are adapted to attach the drawbar (6) immovably and releasably to the chassis (3) in the two or more attachment positions, wherein the drawbar (6) and the chassis (3) are provided with coupling members (11,12) for the releasable attachment of the drawbar (6) to the chassis (3) in two or more vertical positions.