Drawbar Coupling Funnel With Torsional Spring Bias Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Drawbar couplings on vehicles are prone to damage due to insufficient clearance between the road and the coupling when driving on bad roads, leading to potential failure.

Innovation Solution

A drawbar coupling design featuring a funnel, housing cap, and torsional spring with biasing torque mechanism, allowing the funnel to rotate relative to the housing cap, ensuring a biasing torque is applied to maintain the equilibrium position and prevent excessive rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the drawbar coupling is disposed on the chassis, then the coupling is easily accessible and simple to install, but the clearance between the road and the coupling is too small making it prone to damage on bad roads

Engineering Contradiction:
ImproveAccessibility of couplingVSAvoidDamage resistance of coupling
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a rotational degree of freedom between the funnel and housing cap, allowing the coupling to dynamically adapt to road conditions. The funnel can rotate relative to the housing cap within a limited angular range, enabling the coupling to absorb shocks and maintain functionality even when subjected to impacts from bad roads, thus improving reliability while keeping the coupling accessible.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the positional parameter of the coupling by allowing rotational movement between components. The funnel's ability to rotate relative to the housing cap changes the spatial configuration of the coupling, effectively increasing the functional clearance and protecting against damage while maintaining accessibility for installation and operation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the funnel is allowed to rotate freely to accommodate trailer pivoting, then the coupling is versatile and functional, but excessive rotation can cause damage or failure

Engineering Contradiction:
ImprovePivoting capability of trailerVSAvoidFailure risk of coupling
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a dynamic rotational mechanism where the funnel can rotate relative to the housing cap, but the rotation is controlled and limited. The torsional spring provides continuous rotational constraint, allowing the funnel to pivot within a safe angular range to accommodate trailer movements while preventing excessive rotation that would lead to damage or failure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The torsional spring applies a preliminary biasing torque to the funnel in the equilibrium position, creating a pre-constraint that resists excessive rotation before it occurs. This preliminary anti-action prevents the funnel from rotating beyond safe limits by continuously applying a restoring torque that counteracts forces attempting to over-rotate the coupling.

Inventive Principle:
Principle #9Preliminary anti-action

3Volume of moving object

If a torsional spring with shallow helical coil sector is used, then the coupling is compact and space-efficient, but the spring design becomes more complex

Engineering Contradiction:
ImproveSpace efficiency of couplingVSAvoidSpring design complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the torsional spring by introducing a shallow helical coil sector with a helix pitch less than the spring thickness. This parameter change allows the spring to be more compact and space-efficient while maintaining its functional properties. The shallow coil sector is contiguous with a main helical coil sector, creating a optimized geometry that reduces volume without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by having different sections of the torsional spring with different helix pitches. The shallow helical coil sector has a reduced pitch for compactness, while the main helical coil sector has a standard pitch for structural integrity. This localized differentiation optimizes space efficiency in critical areas while maintaining overall spring performance.

Inventive Principle:
Principle #3Local quality

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 design minimizes damage by maintaining the drawbar coupling's alignment and reducing the risk of failure, enhancing durability and space efficiency while allowing pivotal movement of the trailer.

Implementation Method 1

a torsional spring; wherein: the funnel is configured to rotate with respect to the bushing and the housing cap; the funnel defines a toroidal groove in which the torsional spring is received

Methodology Applied
Scientific EffectTorsional spring: Torsion Spring

Implementation Method 2

the first spring tail and the second spring tail are configured to apply a biasing torque to the funnel and the housing cap respectively to bias the funnel and the housing cap towards the equilibrium position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4177086B1A drawbar coupling
Publication Date: 2026.01.28 JOST WERKE DEUTSCHLAND GMBH
  • EP4177086B1 patent drawingFigure 1
  • EP4177086B1 patent drawingFigure 2
  • EP4177086B1 patent drawingFigure 3

AI summary

There is disclosed a drawbar coupling comprising: a funnel around a bushing, a housing cap fixed to the bushing, and a torsional spring; wherein: the funnel is configured to rotate with respect to the bushing and the housing cap; the funnel defines a toroidal groove in which the torsional spring is received, and the housing cap comprises a corresponding recess within which the torsional spring is received, such that the torsional spring is disposed between the funnel and the housing cap; and the torsional spring is provided with a first spring tail and a second spring tail, wherein each spring tail is in contact with both the funnel and the housing cap when the funnel is in an equilibrium position with respect to the housing cap, such that the first spring tail and the second spring tail are configured to apply a biasing torque to the funnel and the housing cap respectively to bias the funnel and the housing cap towards the equilibrium position.