Coupled Elevator Fall Protection Braking Heavier Loads
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Solution Overview
Problem
Existing fall protection systems for elevators are inadequate in braking heavier elevator cages with loads, as they can fail when the load exceeds the system's capacity, leading to incomplete braking or device failure.
Innovation Solution
The system couples multiple identical fall protection devices together, using coupling means such as cables and cams to ensure that if one device activates, it automatically engages the other, providing a redundant braking mechanism to handle heavier loads without the need for new components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single fall protection device is used, then the device structure remains simple, but it cannot handle heavier elevator cages with loads
Solution Approach 1:
The fall protection system is divided into multiple identical fall protection devices (first device and second device), each capable of independently braking the elevator cage. This segmentation allows the system to handle heavier loads by distributing the braking force across multiple devices while maintaining the simplicity of individual device structures.
Solution Approach 2:
Multiple fall protection devices are combined and coupled together through coupling means (cables and cams) to form a unified braking system. The devices work simultaneously to provide enhanced braking capacity for heavier elevator cages while maintaining the structural simplicity of each individual device.
2Reliability
If multiple fall protection devices are coupled together, then heavier loads can be braked, but the coupling mechanism adds complexity
Solution Approach 1:
The coupling mechanism between fall protection devices is designed to activate automatically through self-service. When one device activates during a fall, the coupling means (cables and cams) automatically engage the second device without requiring external control or complex coordination systems, thereby maintaining reliability while minimizing added complexity.
Solution Approach 2:
Coupling cables and cams serve as intermediary elements that connect the fall protection devices. These intermediaries transmit the activation force from one device to another and coordinate their simultaneous operation, enabling reliable multi-device braking while keeping the coupling mechanism relatively simple through mechanical mediation.
3Force
If the brake drum is pressed tightly against the housing, then braking force increases, but the screw thread or housing may break under heavy loads
Solution Approach 1:
The braking force requirement is segmented and distributed across multiple fall protection devices. Each device provides a portion of the total braking force needed to stop the elevator cage, preventing any single device from exceeding its structural strength limits while collectively providing sufficient braking force for heavy loads.
Solution Approach 2:
Multiple brake drums from different fall protection devices are combined to work simultaneously, merging their individual braking forces to achieve the total braking force required for heavy loads. This distributed approach allows the system to generate high braking force without overloading any single structural component.
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
This solution ensures that heavier elevator cages can be safely braked by activating multiple fall protection devices in sequence, preventing device failure and ensuring the elevator cage comes to a safe stop, even when overloaded.
Implementation Method 1
the coupling pawl rotates at high rotational speed of the gear shaft by the centrifugal force of a collapsed position, in which the coupling pawl engages the gear shaft, to an folded-out position where the coupling pawl is moved outwards
Implementation Method 2
a brake drum which is rotatably present in the housing and is in contact with an inside of the housing during braking with a braking surface present on an outside, which brake drum... The fall arrest device brakes the elevator cage after it has dropped at too high a speed
Data Source
AI summary
A lift has a guide, a lift cage which is movable along the guide, lift means for moving the lift cage along the guide, and a fall protection attached to the lift cage provided with coupling pawl (27) which triggers the fall protection device in the event of a downward movement speed of the lift cage, exceeds maximum value. The fall protection has two catches (37a), each of which is provided with a comb (45). These combs are coupled to one another such that when one of the catches comes into action the comb of this catch is activated and thereby activates the comb of the other catch which is the coupling pin (27) of this other capture and will bring this other catch into effect.