Step Roller Threaded Locking Structure for Fast Escalator Assembly
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Solution Overview
Problem
Traditional step roller assemblies for escalators require inconvenient assembly operations due to the need to screw bolts and nuts, leading to low production efficiency and potential loosening issues that increase costs and reduce reliability.
Innovation Solution
A self-locking threaded connection structure for step rollers using a countersunk slot hole with a U-shaped structure and a rib to accurately position the nut, allowing easy assembly and preventing loosening, integrated with a die-casted step for improved manufacturing efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard mechanical components (bolt, washer, nut) are used for fixing the step roller, then the connection can be achieved, but the assembly operation becomes inconvenient and time-consuming
Solution Approach 1:
The mounting shaft is segmented with a through hole and countersunk slot hole that separate the functions of bolt passage and nut positioning. This allows the nut to be pre-positioned in the countersunk slot hole before bolt insertion, eliminating the need for concurrent screwing operations and improving assembly convenience and productivity
Solution Approach 2:
The countersunk slot hole structure enables the nut to self-position and self-align with the through hole automatically during assembly. The U-shaped structure with bottom face and side faces guides the nut into correct orientation, making the assembly process self-serviceable and eliminating complex alignment operations
2Reliability
If standard nuts are used without positioning structure, then the design is simple, but the nut may loosen due to vibration leading to connection failure
Solution Approach 1:
The countersunk slot hole is pre-formed in the mounting shaft to provide a positioning structure for the nut before assembly. This preliminary action ensures the nut is correctly positioned and restrained against loosening forces from the beginning, preventing vibration-induced loosening without adding complex locking mechanisms
Solution Approach 2:
The countersunk slot hole acts as an intermediary structure between the mounting shaft and the nut. It provides the U-shaped positioning environment (bottom face and side faces) that mediates the connection, restraining the nut and preventing loosening while maintaining structural simplicity
3Manufacturing precision
If the nut positioning is not precise, then the assembly is simple, but the alignment between nut hole and through hole is poor leading to assembly difficulties
Solution Approach 1:
The countersunk slot hole uses asymmetric U-shaped structure with bottom face and two side faces that are symmetrical to each other, creating a unique geometric signature that matches the nut shape. This asymmetric positioning ensures only one correct orientation fits, achieving precise alignment automatically during assembly without complex guidance mechanisms
Data Source
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AI summary
A self-locking structure of threaded connection for installing a step roller of an escalator on a step, comprising: the step having a mounting shaft on which the step roller is installed through a rolling bearing; a threaded connection structure comprising a bolt, a washer and a nut, wherein the mounting shaft has a through hole along its axis line direction, the bolt passes through the washer, the through hole and the nut, and the washer presses the inner ring of the rolling bearing against the mounting shaft through the tightening engagement between the bolt and the nut, wherein a countersunk slot hole for placing the nut is formed at the end of the through hole such that the bolt passes through the nut located in the countersunk slot hole, the sidewall of the countersunk slot hole includes a bottom face and two side faces symmetrical to each other, thereby forming a U-shaped structure in which three sides of the sidewall are closed and one side is open; and when the nut is placed in the U-shaped structure and is positioned by the bottom face and the two side faces, the hole of the nut is exactly aligned with the through hole. The self-locking structure improves the assembly efficiency and can prevent the threaded connection from loosening.