Escalator Step Roller Threaded Locking Structure Against Nut Loosening
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Solution Overview
Problem
Traditional step roller assemblies for escalators face inefficiencies in assembly due to the need to manually align and tighten bolts and nuts, leading to increased production costs and potential loosening issues.
Innovation Solution
A self-locking threaded connection structure featuring a countersunk slot hole with a U-shaped sidewall and optional rib for the nut, ensuring precise positioning and preventing loosening, integrated into the die-casted escalator step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional bolt and nut connection is used, then the connection can be assembled, but the assembly operation is inconvenient and production efficiency is low
Solution Approach 1:
The nut is designed with a self-positioning structure that automatically aligns with the bolt hole when placed in the countersunk slot hole. The U-shaped sidewall structure with bottom face and two side faces enables the nut to self-align and self-lock during assembly, eliminating the need for manual alignment operations and significantly improving assembly efficiency
Solution Approach 2:
The countersunk slot hole is pre-formed in the mounting shaft with the U-shaped sidewall structure and bottom face positioned to pre-align with the bolt hole. This preliminary positioning structure ensures that when the nut is placed in the countersunk slot hole, its hole is automatically aligned with the bolt hole, ready for immediate bolt insertion and tightening
2Reliability
If traditional nut and bolt connection is used, then the connection can be made, but the fit may loosen due to vibration leading to failure
Solution Approach 1:
The countersunk slot hole with U-shaped sidewall structure creates a preliminary anti-loosening effect by mechanically constraining the nut. The two side faces of the U-shaped structure press against opposite sides of the nut, preventing it from rotating or loosening under vibrational loads, thus counteracting the loosening tendency before it can occur
Solution Approach 2:
The countersunk slot hole features an asymmetric U-shaped sidewall structure with a bottom face and two side faces that are symmetrical to each other, forming a closed structure on three sides and open on one side. This asymmetric design creates a self-locking effect where the nut is securely positioned and constrained, preventing loosening while maintaining easy assembly from the open side
3Manufacturing precision
If manual alignment of nut and bolt is required, then precise positioning can be achieved, but assembly time increases reducing productivity
Solution Approach 1:
The countersunk slot hole is pre-formed with the U-shaped sidewall structure and bottom face positioned to automatically align the nut with the bolt hole. This preliminary positioning eliminates the need for manual alignment operations, achieving precise nut positioning instantly when the nut is placed in the countersunk slot hole, thereby significantly increasing assembly speed
Solution Approach 2:
The nut automatically positions itself when placed in the countersunk slot hole. The U-shaped sidewall structure with bottom face and two side faces enables the nut to self-align with the bolt hole without external intervention, achieving precise positioning through the self-service mechanism of the structured hole
Data Source
AI summary
A self-locking structure of threaded connection for installing a step roller of an escalator on a step is provided. The step has a mounting shaft on which the step roller is installed through a rolling bearing; a threaded connection structure including 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. 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 forming a U-shaped structure.