Enclosed Proximity Switch Target Magnet Securing
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Solution Overview
Problem
Magnetic proximity switch assemblies used in hazardous environments, such as nuclear applications, face challenges in maintaining secure and sealed configurations to prevent contamination and displacement due to high temperatures, pressures, and seismic loads, which can affect the accuracy and reliability of position sensing.
Innovation Solution
A target support system within an enclosed proximity switch assembly that includes a hub with threaded apertures, a magnet support, and a clamp plate, secured with set screws, which applies a minimum torque of 150 inch-ounces to non-rotatably secure the target magnet to the shaft, ensuring stability and sealing against high-temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target magnet and proximity switch are disposed within a sealed enclosure to protect from damage, then reliability is improved, but device complexity increases due to the need for sealed enclosures and secure mounting mechanisms
Solution Approach 1:
The target support is divided into separate components: a hub with body apertures, a magnet support, and a clamp plate. These segmented parts can be assembled and secured independently using set screws, allowing the complexity to be managed through modular assembly while maintaining the sealed enclosure's protective function
Solution Approach 2:
The hub is pre-formed with threaded body apertures that receive set screws before the target magnet is installed. This preliminary preparation of mounting features allows for secure attachment of the target magnet to the shaft, ensuring reliability without requiring complex post-installation securing mechanisms
2Stability of the object's composition
If set screws are used to non-rotatably secure the target magnet to the shaft with minimum torque of 150 inch-ounces, then stability is improved, but manufacturing precision requirements increase to ensure proper torque application and sealing
Solution Approach 1:
The hub includes body apertures with specific threaded configurations that standardize the torque parameter. By designing the aperture threads and set screw interfaces with precise geometric parameters, the system achieves reliable securing at the specified 150 inch-ounces torque without requiring excessive manufacturing precision in the assembly process
Solution Approach 2:
The set screw mechanism is designed to be self-securing through its threaded engagement with the hub's body aperture. The threaded structure provides inherent mechanical advantage and self-locking characteristics, reducing the need for highly precise torque control while ensuring stable mounting of the target magnet
3Reliability
If the enclosure is sealed to withstand high temperatures and pressures, then reliability is improved, but ease of operation decreases due to difficulty in assembly and maintenance
Solution Approach 1:
The target support components (hub, magnet support, clamp plate) are segmented and can be assembled separately before being installed as a unit in the sealed enclosure. This segmentation allows for easier assembly and maintenance without compromising the integrity of the sealed enclosure that withstands high temperatures and pressures
Solution Approach 2:
The target magnet and its support structure are pre-assembled with set screws secured in the hub's body apertures before installation into the sealed enclosure. This preliminary assembly simplifies the overall installation process and facilitates easier maintenance, as the target support can be accessed as a partially disassembled unit without breaching the sealed enclosure
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 secure and reliable position sensing mechanism that withstands high temperatures, pressures, and seismic loads, maintaining accurate detection of the target magnet's position within the proximity switch assembly, even in hazardous environments.
Implementation Method 1
A minimum torque of 150 inch-ounces is applied to the set screw
Implementation Method 2
the magnetic flux generated by the target magnet causes the lever of the switching circuit to change bias
Data Source
AI summary
A method of non-rotatably securing a target to a shaft extending along a longitudinal axis within an enclosed proximity switch assembly is described. The target support at least one target magnet and a hub having a body portion extending along the longitudinal axis. The body portion includes an outer surface and a shaft aperture extending along the longitudinal axis, and further includes at least one threaded body aperture extending from the outer surface to the shaft aperture. The shaft is inserted into the shaft aperture, and a set screw is inserted into one of the body apertures. A torque is applied to the set screw to threadably engage the set screw with the one of the body apertures such that a distal end of the set screw contacts an outer surface of the shaft. The set screw is sealed within the body aperture with a high-temperature potting.