Passenger Conveyor Auxiliary Brake With Conical Threaded Screw
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Solution Overview
Problem
Conventional passenger conveyors, such as escalators and moving ramps, lack a reliable, compact, and simple auxiliary brake to effectively stop movement in situations like uncontrolled rushing due to passenger weight or machinery failures.
Innovation Solution
A passenger conveyor system featuring a brake mechanism with a screw member and nut having conical threaded rims, where the screw and nut are screwed together and connected to a diverting wheel, allowing for relative rotation to generate a strong braking force by tightening and resisting rotation, along with a control arrangement to activate the stopping device when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional brake system is used for stopping the passenger conveyor, then the stopping function is provided, but the brake system is not reliable, compact, or simple enough for auxiliary braking in emergency situations
Solution Approach 1:
The brake mechanism is integrated within the diverting wheel assembly, with the screw member and nut member nested together. The screw member is positioned inside the nut member, and both are contained within the compact diverting wheel structure. This nesting approach achieves a reliable auxiliary brake function without adding external complexity to the overall system.
Solution Approach 2:
The auxiliary brake function is merged with the existing diverting wheel mechanism. The screw member connects to the diverting wheel, and when the stopping device activates, it causes relative rotation between the screw and nut members, generating braking force through their threaded engagement. This combining approach provides a reliable stopping function while utilizing existing structural components.
2Volume of moving object
If a compact brake mechanism is implemented, then the device size is reduced, but the braking force may be insufficient
Solution Approach 1:
The conical threaded rims of the screw and nut members are designed with specific geometric parameters optimized for generating high braking force in a compact volume. The conical shape and thread configuration transform rotational motion into strong frictional contact force, achieving effective braking within the limited space of the diverting wheel assembly.
Solution Approach 2:
The friction that would normally be considered a resistive force is converted into the beneficial braking mechanism. The relative rotation between the screw and nut members generates friction at their conical threaded contact surfaces, and this friction force is harnessed to create the stopping effect. The friction that opposes motion is transformed into the useful braking force needed to stop the conveyor.
3Device complexity
If a simple brake structure is used, then the device complexity is reduced, but the stopping speed and reliability may be compromised
Solution Approach 1:
The screw and nut members are designed to automatically generate braking force through their own relative rotation. When the stopping device causes the screw member to rotate relative to the nut member, the threaded engagement self-generates friction-based braking force without requiring additional actuating mechanisms. This self-service mechanism achieves swift stopping while maintaining structural simplicity.
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, compact, and swift stopping mechanism that effectively halts the conveyor, even in inclined sections, by utilizing the friction generated from the conical threads and controlled activation, ensuring passenger safety.
Implementation Method 1
The brake comprises a screw member having a conical threaded external rim, and a nut member having a conical threaded internal rim. The threads of the screw and nut are particularly counterparts for each other. The screw member and nut member are screwed together, in particular such that the nut member is around the screw member, their threads engaging each other.
Data Source
AI summary
The invention relates to a passenger conveyor, such as an escalator or autowalk, comprising a band of conveying elements; a diverting wheel for diverting the passage of the band of conveying elements and/or a traction member thereof and a brake for braking rotation of the diverting wheel. The brake comprises a screw member having a conical threaded external rim; a nut member having a conical threaded internal rim, the screw member and nut member being screwed together, one of said screw member and nut member being connected with the diverting wheel for being driven by the diverting wheel. The brake further comprises a stopping device for stopping rotation of the other of said screw member and nut member.