Magnetic Security Switch for Shipping Containers
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Solution Overview
Problem
Prior security systems for shipping containers are vulnerable to unauthorized access due to the use of reed switches that can be manipulated by external magnets, and they require AC power, which is not feasible for all applications.
Innovation Solution
A security assembly with magnetically coupled switch members and a spring-biased plunger mechanism that changes state upon door movement, triggering an alarm controller and circuitry, which is self-contained and powered by a battery, allowing for remote signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reed switches are used in magnetic security systems, then the system can detect door openings, but the system becomes vulnerable to unauthorized manipulation by external magnets
Solution Approach 1:
The switch member is divided into two separate switch elements (first and second switch elements) with a conductive body that can simultaneously contact both elements. This segmentation prevents unauthorized activation because an external magnet would need to simultaneously manipulate the body into contact with both elements, which is mechanically difficult and detectable by the alarm circuit.
Solution Approach 2:
A non-conductive ball member is introduced as an intermediary between the magnetic plunger and the switch elements. The ball member is magnetically coupled to the plunger but electrically isolated, allowing magnetic force transmission while preventing direct electrical contact that could be exploited by external magnets. The alarm circuit monitors the electrical state changes of the switch elements to detect unauthorized manipulation.
2Reliability
If AC power is required for security systems, then the system can operate with stable power supply, but the system becomes infeasible for shipping containers without power access
Solution Approach 1:
The security system is designed to be self-powered through a battery contained within the housing, eliminating the need for external AC power supply. The battery provides autonomous operation for the alarm circuit, switch members, and signal transmission components, making the system fully adaptable to shipping containers and other applications without power access. The system includes all necessary components (battery, alarm circuit, transmission antenna) to operate independently.
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 reliable detection of unauthorized door openings in shipping containers, ensuring secure operation without the need for AC power and resistance to external magnet manipulation, enabling effective alarm initiation and remote tracking.
Implementation Method 1
The shiftable component and proximal switch member body are being magnetically coupled such that movement of the component between the first and second component positions effects corresponding movement of the body between the first and second body positions
Data Source
AI summary
Switch-controlled security assemblies (20, 76) are provided which are especially designed for use with cargo enclosures (40), in order to detect any unauthorized opening of the cargo doors (38). The assemblies (20, 76) include one or more switch assemblies (26, 28) each having a switch member (44) and an associated shiftable component (46). In preferred forms, the switch member (44) includes a pair of switch elements (50, 52) and a body (54) movable between a first position in simultaneous electrical contact with the elements (50, 52), and a second position out of such simultaneous contact. The body (54) and components (46) are magnetically coupled such that movement of the component (46) during unauthorized opening of door (38) effects corresponding movement of the body (54), in turn actuating an alarm controller (30).