Electromagnetic Safety Brake for Elevator Guide Rails
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Solution Overview
Problem
Elevator systems, particularly in high-rise buildings, face significant risks due to freefall and over-speed issues, where existing mechanical and electromechanical safety brake systems are inefficient in quickly and reliably engaging to stop the elevator car, often requiring complex mechanical linkages and multiple components.
Innovation Solution
A safety brake device that integrates an electromagnet and a pad with a high-friction surface, where the pad moves from a non-engaging to an engaging position with the guide rail under biasing force, creating a sufficient frictional force to stop the elevator car, and automatically resets by magnetic force when power is restored, reducing component count and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mechanical governor and mechanically-actuated safety brake systems are used, then the safety brake can stop the elevator car, but the system requires complex mechanical linkages and multiple components
Solution Approach 1:
The patent replaces the traditional mechanical governor and linkage system with an electromagnetic actuator that directly controls the safety brake. The electromagnetic component uses magnetic fields to actuate the brake pad, eliminating complex mechanical linkages while maintaining reliable braking engagement. This substitution reduces the number of moving parts and simplifies the overall system architecture.
Solution Approach 2:
The patent combines the safety brake and electromagnetic actuator into a single integrated device. The brake assembly includes the electromagnetic component, pad, and mounting structure as one unified unit, reducing the number of separate components that need to be installed and maintained. This merging approach simplifies the system while preserving safety functionality.
2Device complexity
If the safety brake device integrates fewer components, then the space required and cost are reduced, but the braking force and reliability may be compromised
Solution Approach 1:
The patent optimizes the electromagnetic actuator parameters to generate sufficient force for reliable brake engagement. By adjusting magnetic field strength, coil configuration, and actuator geometry, the system achieves adequate braking force with fewer components. The high-friction pad material also contributes to achieving required stopping power with reduced mechanical complexity.
Solution Approach 2:
The patent employs composite or optimized material selection for the brake pad, using high-friction materials that maximize braking efficiency. This allows the system to achieve required braking force with a simpler, more compact design, as the enhanced material properties compensate for the reduced number of mechanical components.
3Speed
If the electromagnet is used to hold the pad in position, then the system can quickly engage the brake, but energy is continuously consumed to maintain the non-braking state
Solution Approach 1:
The patent inverts the traditional fail-safe approach by using a spring-loaded system that naturally engages the brake, with the electromagnet serving only to release it during normal operation. This reversal means energy is consumed only when braking is NOT needed, rather than continuously when braking IS needed. The spring provides the holding force during descent, and the electromagnet merely overcomes this spring force to disengage the brake when safe.
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 more compact, cost-effective, and modular safety brake system that can efficiently engage and disengage to prevent freefall and over-speed conditions, ensuring reliable operation with fewer components and easier adaptation to various conveyance systems.
Implementation Method 1
an electromagnet which is arranged to apply a magnetic force to the pad to counteract the biasing force
Implementation Method 2
the contact between the pad in the second position and the guide rail results in a frictional force between the pad and the guide rail
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A safety brake device (40; 140; 240; 340; 440; 540), for use in a conveyance system (10) including a guide rail (20) and a component (16) moveable along the guide rail (20), comprises a safety brake (48) moveable between a non-braking position where the safety brake (48) is not in engagement with the guide rail (20) and a braking position where the safety brake (48) is engaged with the guide rail (20). The safety brake device (40; 140; 240; 340; 440) also comprises an actuator (52; 152; 252; 352; 452) for the safety brake (48), and the actuator (52; 152; 252; 352; 452) comprises a mounting portion (42) for mounting the actuator (52; 152; 252; 352; 452) to the component (16), a pad (54; 154; 254; 354; 454) arranged to be moveable relative to the mounting portion (42) between a first position spaced from the guide rail (20) and a second position in contact with the guide rail (20), and at least one biasing member (56) configured to apply a biasing force to move the pad (54; 154; 254; 354; 454) from the first position to the second position. A linkage mechanism (50) is coupled between the safety brake (48) and the actuator (52; 152; 252; 352; 452) such that, when the mounting portion (42) is moving downwards relative to the guide rail (20), movement of the pad (54) to the second position creates an upwards reaction force transmitted by the linkage mechanism (50) to move the safety brake (48) into the braking position. The pad (54; 154; 254; 354; 454) comprises a ferromagnetic material and the actuator (52; 152; 252; 352; 452) further comprises an electromagnet (62; 162; 262; 362) operable to apply a magnetic field to pad (54; 154; 254; 354; 454) and thereby create a magnetic force acting against the biasing force to move the pad (54; 154; 254; 354; 454) towards the first position.