Trailer Break-Away Switch Using Magnetic Field Detection
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Solution Overview
Problem
Existing break-away switches for trailers suffer from mechanical failures due to corrosion, contamination, and unintended activation of trailer brakes, particularly when submerged in conductive liquids or contaminated with conductive materials, leading to hazardous situations during unintended decoupling from a towing vehicle.
Innovation Solution
A non-contacting switch using a field effect transistor (FET) activated by a magnetically activated device, such as a Hall effect chip or reed switch, which remains off when a ferromagnetic component is present and turns on when removed, ensuring safe and reliable activation of trailer brakes upon decoupling, with a housing design that secures the electronics and includes a ferromagnetic pin and o-ring for protection and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If mechanical contacts and springs are used in the break-away switch, then the switch can be simple in structure, but the reliability deteriorates due to corrosion, contamination, and failure modes
Solution Approach 1:
The patent replaces the mechanical contact and spring system with a magnetic field-based detection system using a Hall effect sensor or reed switch. This substitution eliminates physical contacts that corrode and springs that break, achieving reliable operation without mechanical wear or contamination issues while maintaining structural simplicity.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the ferromagnetic component position and the switch activation. The Hall effect sensor or reed switch detects changes in magnetic flux caused by the movement of the ferromagnetic component, providing reliable signal transmission without direct mechanical or electrical contact between moving and stationary parts.
2Object-affected harmful factors
If seals are added to prevent contamination, then the protection against contaminants improves, but moisture condensation within the housing causes corrosion of contacts
Solution Approach 1:
By replacing the mechanical contact system with a magnetic field-based detection system, the patent eliminates the contacts that would otherwise corrode from moisture condensation. The Hall effect sensor or reed switch has no exposed electrical contacts inside the sealed housing, making the system immune to corrosion while maintaining the seal for contaminant protection.
3Object-affected harmful factors
If the switch is submerged in conductive liquid or contaminated with conductive material, then the switch housing is protected, but the trailer brakes are inadvertently actuated
Solution Approach 1:
The magnetic field-based detection system is immune to conductive liquids and contaminants that would affect electrical contacts. The Hall effect sensor or reed switch detects magnetic field changes rather than relying on electrical continuity, preventing false activation from conductive contamination while maintaining housing protection.
Solution Approach 2:
The magnetic field serves as an intermediary that is not affected by conductive liquids or contaminants. Unlike electrical contacts that would create false circuits in conductive environments, the magnetic field penetrates the housing and detects ferromagnetic component position reliably regardless of external conductive contamination.
4Reliability
If non-conductive mechanism is used to separate contacts, then the switch can operate without direct contact, but broken springs fail to actuate the contacts
Solution Approach 1:
The patent replaces the spring-based mechanical actuation system with a magnetic force-based system. The ferromagnetic component is attracted to or repelled from the permanent magnet, providing reliable actuation without springs that can break. This substitution maintains contact separation reliability while simplifying the actuation mechanism.
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 solution provides a reliable and safe mechanism to activate trailer brakes during unintended decoupling, preventing hazardous brake activation and maintaining functionality even with o-ring damage, while ensuring the switch remains operational and testable through an LED indicator.
Implementation Method 1
the magnetic flux from a permanent magnet is insufficient to turn on the magnetically activated device keeping the FET turned off
Implementation Method 2
A field effect transistor ('FET') is activated by a magnetically activated device, such as a Hall effect chip or reed switch
Implementation Method 3
When a ferromagnetic component is in close proximity to the magnetically activated device, the magnetic flux from a permanent magnet is insufficient to turn on the magnetically activated device
Implementation Method 4
a light emitting diode (LED) that is used to indicate when the FET is turned on and when the switch is electrically closed
Data Source
AI summary
A trailer break-away switch comprises an electromechanical means to energize a towed trailer brake in the event of unintended decoupling of the trailer from the towing vehicle. When in normal operation, the trailer break-away switch operates as a normally open switch between the stored energy source (the battery) on the trailer and the trailer brake system. In the event of unintended decoupling of the trailer from the towing vehicle, a pin is pulled from the trailer break-away switch, which activates the switch. Activating the switch allows electrical power to be connected to the trailer brake system. In some cases, the switch directly connects a trailer battery to the electromagnetic coils of the electric brakes.