Diamond-Coated Elevator Safety Brake for Overspeed Stopping
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Solution Overview
Problem
Existing safety brake systems for elevator systems face challenges in effectively stopping an elevator car from descending in case of an overspeed condition, especially when the tension member breaks, due to insufficient frictional engagement with the guide rail.
Innovation Solution
A braking mechanism featuring a wedge with a frictional surface coated with polycrystalline blocky diamond material, applied via vacuum brazing with a nickel chromium alloy, providing a high coefficient of friction and durable engagement with the guide rail to arrest the elevator car's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional friction materials are used in the safety brake wedge, then the braking mechanism can engage with the guide rail, but the frictional engagement is insufficient to reliably stop the elevator car in overspeed conditions
Solution Approach 1:
The patent applies a diamond coating (superhard material) onto the wedge surface, creating a composite structure that combines the toughness of the base wedge material with the extreme hardness and high friction coefficient of diamond. This composite approach enables the friction surface to generate sufficient stopping force reliably while maintaining durability under extreme braking conditions.
Solution Approach 2:
The patent changes the surface properties of the wedge by coating it with diamond material, fundamentally altering the friction coefficient and wear resistance parameters. This parameter change transforms the friction surface from conventional materials with inadequate friction characteristics to a diamond-coated surface with exceptionally high friction capability, ensuring reliable engagement with the guide rail.
2Duration of action of stationary object
If the friction surface material has high hardness to resist wear, then durability is improved, but the material may lack sufficient friction coefficient for effective braking engagement
Solution Approach 1:
The diamond-coated wedge creates a composite material system where the diamond layer provides both extreme wear resistance and high friction coefficient. This resolves the contradiction by demonstrating that superhard materials like diamond can simultaneously deliver both durability and sufficient frictional engagement, unlike conventional materials that must trade off between these properties.
Solution Approach 2:
The patent applies the diamond coating specifically to the friction surface of the wedge where engagement with the guide rail occurs. This local application ensures that the area requiring both high hardness for wear resistance and high friction coefficient receives the specialized diamond treatment, while the rest of the wedge structure maintains its structural integrity.
3Ease of manufacture
If conventional coating methods are used, then manufacturing is simpler, but the coating may not provide sufficient adhesion or durability under thermal cycling and corrosion conditions
Solution Approach 1:
The patent replaces conventional mechanical or chemical coating methods with a thermal field approach ( Plasma Arc Coating or HVOF). This substitution uses high-temperature plasma or combustion fields to deposit and bond the diamond coating, creating a metallurgically bonded layer that far exceeds the adhesion and durability achievable with conventional coating techniques.
Solution Approach 2:
The patent employs extreme parameter conditions during coating application, using temperatures exceeding 10,000°C in plasma arc coating or high-velocity combustion in HVOF. These parameter changes enable the diamond particles to fuse with the substrate and each other, creating a coating with exceptional adhesion and resistance to thermal cycling and corrosion that cannot be achieved with conventional low-temperature coating methods.
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 ensures reliable and efficient stopping of the elevator car by providing exceptional frictional performance, minimizing wear, and being resistant to corrosion and thermal cycling, thus addressing the inadequacies of current safety brake systems.
Implementation Method 1
The friction coating provides a high coefficient of friction and durable engagement with the guide rail to arrest the elevator car's movement
Implementation Method 2
The friction coating is secured to the frictional surface via vacuum brazing with a nickel chromium alloy brazing paste
Data Source
AI summary
A braking mechanism includes a wedge selectably engageable with a guide rail, and a frictional surface defined on the wedge configured for selective engagement with the guide rail in an overspeed condition. The frictional surface includes a friction coating of polycrystalline blocky diamond material. An elevator system includes an elevator car, a guide rail along which the elevator car travels, and a braking mechanism located at the elevator car and selectably engageable with the guide rail to slow or stop travel of the elevator car along the guide rail. The braking mechanism includes a wedge having a frictional surface configured for selective engagement with the guide rail in an overspeed condition. The frictional surface includes a friction coating of polycrystalline blocky diamond material.