Fifth-Wheel Angle Sensing With Spring-Loaded Contact Tracking

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Solution Overview

Problem

Existing sensor systems for determining the articulation angle between a commercial vehicle and a trailer are limited by the need for additional stabilization measures when retrofitted, and they often provide erroneous readings due to contamination or limited measuring ranges.

Innovation Solution

A sensor system comprising a wheel-mounted rotary encoder and a spring-loaded positioning mechanism that allows easy retrofitting without reducing stability, ensuring continuous measurement by positioning the sensor unit's wheel to maintain contact with the trailer's contact surface, even during large rotational movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a roller sensor is integrated into an opening in the fifth wheel, then direct measurement of the articulation angle is enabled, but the stability of the fifth wheel coupling must be ensured by additional reinforcement

Engineering Contradiction:
Improvearticulation angle measurementVSAvoidfifth wheel coupling stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces a magnetic coupling system as an intermediary between the sensor and the mechanical components. The sensor unit with magnet and the counterweight with magnet create a magnetic field-based connection that enables articulation angle measurement without physical contact or openings in the fifth wheel, thus maintaining structural stability while achieving measurement functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical roller sensor system with a magnetic field-based sensing system. Instead of using physical contact through openings, the invention uses magnetic coupling between the sensor unit and counterweight to detect articulation angle changes, eliminating the need for structural modifications to the fifth wheel

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If sensors are mounted on the commercial vehicle in direct contact with the trailer, then relative movement between the vehicles can be measured, but the sensors are often only usable within a specific measuring range of the articulation angle

Engineering Contradiction:
Improverelative movement measurementVSAvoidmeasuring range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic sensor system where the sensor unit can rotate relative to the counterweight, allowing the measuring system to adapt to different articulation angles. The magnetic coupling enables continuous tracking of angle changes beyond fixed mechanical limits, providing a versatile measuring range that accommodates various operating conditions

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If an existing trailer coupling is retrofitted with a sensor system requiring an opening, then sensor installation is enabled, but the retrofit cannot be easily performed as a stability-reducing opening cannot be easily created

Engineering Contradiction:
Improvesensor installationVSAvoidretrofit capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical contact-based sensing with magnetic field-based sensing, allowing the sensor unit to be mounted on the counterweight without creating openings in the fifth wheel. This enables easy retrofitting of existing trailer couplings while maintaining structural integrity and stability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables reliable and continuous measurement of the articulation angle without damaging the sensor system during coupling and uncoupling, and adapts to various trailer hitches without design modifications.

Implementation Method 1

The positioning mechanism is designed to support the movable part in at least one operating position, preferably within a range of operating positions. This support is designed as a spring-loaded support.

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3810443B1Sensor system for a utility vehicle and fifth-wheel coupling system, utility vehicle comprising said sensor system, and method for same
Publication Date: 2026.03.11 ZF CV SYST EURO BV
  • EP3810443B1 patent drawingFigure 1~3
  • EP3810443B1 patent drawingFigure 4~5
  • EP3810443B1 patent drawingFigure 6~8

AI summary

The invention relates to a sensor system (70) for a utility vehicle (10) which has a trailer coupling (14), in particular a tractor (16), for determining an angular change (17) between the utility vehicle (10) and a towed vehicle trailer (12), in particular a semi-trailer (18). The sensor system (70) comprises a sensor unit (82) with a wheel (84) which is rotatably mounted about an axis (86) and a rotary transmitter (88) which is connected to the wheel (84) in order to detect a change in the position of the wheel (84). The sensor system (70) additionally comprises a mounting (72) and a positioning mechanism (92). The invention additionally relates to a fifth-wheel coupling system (114) with a fifth-wheel coupling (20) and a sensor system (70), to a utility vehicle (10) with a fifth-wheel coupling system (114), and to a method for arranging a sensor system (70) and for coupling a semi-trailer (18) to a tractor (16).