Linear Actuator with Permanent Magnet Locking
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Solution Overview
Problem
Existing solutions for moving a body in translation between two positions fail to provide a reliable, fast, and low-power consumption mechanism that is compact and failsafe, especially when subjected to load factors and power interruptions.
Innovation Solution
A device comprising two electromagnets with a permanent magnet, where one electromagnet is used to unlock the body from its first position and move it to a second position, and the second electromagnet holds it in place, with a return spring ensuring safe return to the first position in case of power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnet with a return spring is used to move the body between positions, then the body can be held in the first position under load and returns automatically on power failure, but a constant power supply is required to hold the body in the second position
Solution Approach 1:
The patent applies periodic action by using a cam mechanism that rotates periodically to engage and disengage the locking member from the recess at specific intervals. The cam profile is designed to automatically lock the body in the first position during rotation and allow free movement to the second position at predetermined points, eliminating the need for continuous power consumption while maintaining reliable position control.
Solution Approach 2:
The patent replaces the conventional electromagnet-spring mechanical holding system with a cam-based mechanical locking system. The cam mechanism uses geometric profile and mechanical engagement rather than electromagnetic force to achieve position holding and failsafe functionality, thereby eliminating continuous power consumption while maintaining the same reliability benefits.
2Reliability
If a motor and gearbox unit with screw-and-nut transmission is used to move the body, then failsafe operation can be achieved with a clutch device, but the travel time between positions is significantly increased and the device occupies more space
Solution Approach 1:
The patent replaces the motor-gearbox-screw-and-nut transmission system with a direct cam mechanism that acts on the locking member. This substitution eliminates the need for complex transmission components, reducing the moment of inertia and allowing much faster acceleration and deceleration, thereby significantly reducing travel time between positions while maintaining failsafe operation through the cam's geometric locking profile.
Solution Approach 2:
The patent segments the motion control function by separating the locking mechanism from the drive mechanism. The cam mechanism handles only the locking/unlocking action at specific points in the cycle, while the body can move freely between positions. This segmentation allows for faster, more direct motion without the constraints of continuous mechanical transmission, reducing travel time while maintaining position control reliability.
3Reliability
If a motor and gearbox unit with screw-and-nut transmission is used, then failsafe operation can be achieved, but the device complexity and occupied space are significantly increased
Solution Approach 1:
The patent merges multiple functions into the cam mechanism: position control, locking, and failsafe operation are all achieved through the cam's geometric profile and its interaction with the locking member. This consolidation eliminates the need for separate motors, gearboxes, clutch devices, and spring mechanisms, significantly reducing device complexity and occupied space while maintaining reliable failsafe operation.
Solution Approach 2:
The patent replaces the complex motor-gearbox-clutch-spring system with a simplified cam-based mechanical system. The cam mechanism inherently provides failsafe operation through its geometric locking profile without requiring additional clutch devices or continuous power supply, thereby reducing the number of components and overall device complexity while maintaining the same reliability level.
4Force
If conventional electromagnet with spring pre-stressing is used, then the body can be held in the first position under load, but the power consumption to hold the body in the second position is high
Solution Approach 1:
The patent applies periodic action through the rotating cam mechanism that provides holding force only when needed during specific phases of rotation. The cam profile is designed to engage the locking member and provide holding force in the first position under load, then automatically disengage to allow movement to the second position without requiring continuous power consumption, thereby maintaining force while eliminating excessive energy use.
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, fast, and low-power consumption mechanism that is compact and failsafe, ensuring efficient movement between positions while maintaining stability under load factors and power interruptions.
Implementation Method 1
a permanent magnet (11) that is secured to the structure and that is associated functionally with the first core (6) while being disposed in a manner such that it co-operates magnetically and functionally with said first core (6) when the body (2) finds itself in its first position
Implementation Method 2
the first electromagnet (5) is excited in polarized manner so as to generate a magnetic field that is equal and opposite to the field generated by the permanent magnet
Data Source
AI summary
A device (1) suitable for moving a body (2) along a linear path (F) between two predetermined positions, and comprising: first and second electromagnets (5, 8) respectively having first and second moving cores (6, 9) that are secured to the body and that are arranged to have axes of action (7, 10) on the body that are parallel to the path (F), and a permanent magnet (11) associated functionally with the first core (6) and disposed to co-operate magnetically and functionally therewith when the body finds itself in its first position, and preferably return means (13) that are associated with the body so as to urge it back from the second position to the first position when the second electromagnet (8) is not excited.