People Conveyor Drive Linkage for Smaller Sprocket Diameter
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Solution Overview
Problem
The existing drive systems for people conveyors, such as escalators and moving walkways, are limited by the diameter of sprockets which restrict the vertical dimension due to the length of chain links, necessitating a reduction in chain link length to minimize sprocket diameter and vertical space requirements.
Innovation Solution
A drive system comprising a conveyance chain with shorter chain links connected by levers and legs, where the legs are pivotably connected to the chain links and extend parallel to the conveyance chain, allowing for a reduced pitch and enabling a smaller sprocket diameter, thereby reducing the vertical space needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the chain link length is reduced to minimize sprocket diameter, then the vertical dimension is reduced, but the structural complexity increases due to the need for levers and legs mechanism
Solution Approach 1:
The drive system is segmented into distinct functional components: conveyance chain for power transmission, legs for structural support and connection, and levers for motion transformation. This segmentation allows each component to be optimized independently, enabling shorter chain links while maintaining structural integrity through the leg-lever assembly.
Solution Approach 2:
The leg-lever mechanism introduces dynamic motion transformation, converting the rotational motion from the sprocket into the appropriate conveyance motion. The levers pivot relative to the legs, creating a dynamic system that can accommodate shorter chain links while maintaining the required conveyance path and sprocket engagement.
2Length of stationary object
If shorter chain links are used, then the sprocket diameter can be reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The segmentation of the drive system into conveyance chain, legs, and levers allows the chain link pitch to be independently controlled and manufactured with higher precision. The legs and levers act as intermediate elements that can compensate for minor variations, enabling shorter chain links to be manufactured with the required precision more feasibly.
Solution Approach 2:
By changing the geometric parameters of the leg-lever mechanism (link lengths, pivot positions, angles), the system can be tuned to accommodate shorter chain links while maintaining the required motion accuracy and sprocket engagement, effectively decoupling the chain link length from the sprocket diameter constraint.
3Volume of moving object
If the pitch of the conveyance chain is reduced, then the vertical space requirement is minimized, but the device complexity increases due to additional components
Solution Approach 1:
The leg and lever components are merged into an integrated assembly that performs multiple functions: structural support, motion transformation, and chain link connection. This merging reduces the number of separate components needed while achieving the required pitch reduction and vertical space minimization.
Solution Approach 2:
The leg-lever assembly serves multiple functions simultaneously: it supports the conveyance chain, transforms rotational motion to linear conveyance motion, provides structural stability, and enables the reduced pitch configuration. This multi-functionality reduces overall device complexity despite the shorter chain links.
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 configuration allows for a significant reduction in the vertical dimension of the people conveyor by shortening the chain links and sprocket diameter, resulting in a more compact design with reduced space requirements.
Implementation Method 1
A first end of each of the levers (40) is pivotably connected to one of the chain links (36) and a second end to one of the legs (38), respectively
Implementation Method 2
Two legs (38) extending in opposite directions basically parallel to the conveyance direction are pivotably connected to the second end of each of the levers (40)
Data Source
Figure 1
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Figure 3
AI summary
A drive system (35) for a people conveyor (1) comprises a conveyance chain (15) including a plurality of chain links (36) connected to each other; a plurality of legs (38) configured for connecting the conveyance chain (15) with the conveyance elements (13); and a plurality of levers (40). Each leg (38) is connected to at least two different chain links (36) by at least two of the levers (40). Each of the levers (40) is pivotably connected to one of the chain links (36) and pivotably connected to one of the legs (38).