Centrifugal Brake for Elevating Platform Mast
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Solution Overview
Problem
Existing elevating platform assemblies lack a reliable and quick braking mechanism to prevent uncontrolled downward movement, particularly at high descent rates, which can lead to safety hazards and potential damage from abutting or breaking of teeth on the braking system.
Innovation Solution
A centrifugal actuator-driven spring-loaded brake system that engages the rack on the mast when the platform descends at a rate above a threshold, using a drum assembly and trigger mechanism to synchronize the teeth meshing and deploy the braking rack with a low-friction sliding mechanism for smooth engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a braking mechanism is provided to prevent uncontrolled downward movement, then safety is improved, but the complexity of the braking system increases and may lead to tooth breakage or free fall if not properly synchronized
Solution Approach 1:
The brake rack is pre-positioned with its teeth aligned to engage the rack teeth at the precise moment of activation. The centrifugal actuator prepares the braking system in advance by rotating the brake rack into the correct position before the braking force is applied, ensuring immediate and effective engagement without tooth breakage or free fall.
Solution Approach 2:
The centrifugal actuator serves as an intermediary mechanism between the uncontrolled descent and the braking action. It translates the excessive descent speed into rotational motion that both triggers and positions the brake rack, mediating the transition from normal operation to emergency braking while maintaining tooth synchronization.
2Speed
If the brake engages quickly to arrest rapid descent, then response time is improved, but the risk of tooth breakage increases without proper synchronization
Solution Approach 1:
The brake rack teeth are pre-aligned with the rack teeth before braking engagement. The centrifugal actuator rotates the brake rack into the correct positional relationship during the approach to braking, so that when the brake engages quickly, the teeth are already in proper alignment and can withstand the impact forces without breaking.
3Reliability
If the braking rack is spring-loaded for automatic engagement, then reliability of braking activation is improved, but the force required to overcome the spring bias and synchronize teeth meshing increases
Solution Approach 1:
The centrifugal actuator acts as a force-multiplying intermediary that converts the rotational motion from excessive descent speed into the linear force needed to overcome the spring bias. By using the kinetic energy already present in the system, it amplifies the force available for brake engagement without requiring additional external force inputs.
Solution Approach 2:
The system changes the parameter of force availability dynamically. During normal operation, the spring bias holds the brake disengaged. During excessive descent, the centrifugal actuator converts kinetic energy into increased force, overcoming the spring bias and enabling brake engagement. The force parameter transitions from insufficient (spring bias only) to sufficient (centrifugal force + spring force) when needed.
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 synchronized and reliable braking, preventing free fall and tooth breakage by ensuring clean meshing of teeth and automatic resetting, ensuring safety and maintaining system integrity during emergency stops.
Implementation Method 1
a centrifugal actuator communicating with said input gear assembly
Implementation Method 2
a spring-loaded brake responsive to said centrifugal actuator to engage said rack and arrest said platform
Data Source
AI summary
A braking device for an elevated platform assembly comprising a platform moveable along a generally vertical mast supporting an upright rack comprises an input gear assembly in mating engagement with the rack, a centrifugal actuator communicating with the input assembly and a spring-loaded brake responsive to the centrifugal actuator. The spring-loaded brake engages the rack and arrests the platform when the platform descends the mast at a rate above an upper threshold limit.