Conveyor Frame Tuned Mass Damper for Swing Reduction
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Solution Overview
Problem
Passenger conveyor systems, such as escalators and moving sidewalks, are prone to natural oscillation and swing due to being fixed at only their ends, leading to instability and potential safety issues.
Innovation Solution
The integration of a compensation means featuring a movable compensation mass connected to the conveyor frame via spring and damper systems, acting as a tuned mass damper, which counteracts natural oscillations by moving anti-cyclically to reduce amplitude, and an active system with movement sensors and a swing drive to adjust and control the compensation mass's movement based on detected swing frequencies and phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the conveyor frame is fixed only at its ends to allow free running over its entire length, then the ease of installation and adaptability to architectural designs is improved, but the stability and susceptibility to swing increases
Solution Approach 1:
The patent introduces compensation means as an intermediary element between the conveyor frame and the building structure. This compensation means includes a compensation mass movably mounted to the conveyor frame via spring means, which acts as a mediator to absorb and counteract oscillations, thereby maintaining stability while preserving the end-fixing installation method that provides architectural adaptability
2Productivity
If the conveyor frame is made longer to span wider areas, then the productivity and coverage area are improved, but the susceptibility to natural oscillation and swing increases
Solution Approach 1:
The patent converts the harmful natural oscillations into beneficial anti-cyclic movements by utilizing the compensation mass. The compensation mass is tuned to swing anti-cyclically to the frame's natural oscillation, thereby reducing the amplitude of harmful vibrations. This allows longer conveyor frames to span wider areas while the compensation means transforms the inevitable oscillations into a stabilizing mechanism
3Stability of the object's composition
If compensation means are added to reduce swing, then the stability is improved, but the device complexity increases
Solution Approach 1:
The patent employs parameter changes by tuning the compensation mass and spring means to specific values that match the natural frequency of the conveyor frame. By adjusting the mass and spring constant parameters, the system achieves optimal anti-cyclic compensation without requiring complex active control systems, thereby improving stability while limiting the increase in device complexity
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 effectively reduces the susceptibility of passenger conveyor systems to swing and natural oscillation, enhancing stability and safety by actively compensating for vibrations and resonance, particularly in long conveyor frames fixed at their ends.
Implementation Method 1
a compensation mass movably mounted to the conveyor frame via a corresponding spring means
Implementation Method 2
at least one damper is mounted between the compensation mass and the conveyor frame
Implementation Method 3
The damper represents energy absorbing element of the suspension of the compensation mass. It can be embodied as a separate component based on restricted flow of viscous fluid
Implementation Method 4
allows the compensation mass to swing anti-cyclic to the frame to reduce the amplitude of natural oscillation of the conveyor
Implementation Method 5
The compensation means is then designed to act as a tuned mass damper to eliminate the natural oscillation of the conveyor track
Data Source
AI summary
The invention refers to a passenger conveyor system comprising a longitudinal conveyor frame having at its longitudinal ends mounting points, a conveyor unit mounted to the conveyor frame and comprising an endless conveyor means comprising an upper conveyor track and a lower return track and turnover means at the conveyor unit ends to turn the conveyor means from the conveyor track to the return track and vice versa, and at least one compensation means comprising a compensation mass which is in transversal direction of the conveyor frame movably mounted to the conveyor frame via a spring means or a swing drive.