Spliced Joint Formation in Thermoplastic Handrails
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Solution Overview
Problem
Existing methods for forming spliced joints in handrails, particularly for escalators and moving walkways, are inefficient and lack a comprehensive process for ensuring a strong and durable bond between handrail ends.
Innovation Solution
A method involving precise cutting and assembly steps using a splicing mandrel, heat paddles, and hot air guns to create interweave patterns, weld thermoplastic layers, and apply adhesive plies to form a robust spliced joint in handrails, ensuring a secure and seamless connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional methods are used to form spliced joints in handrails, then the process is simpler, but the bond strength and durability between handrail ends are insufficient
Solution Approach 1:
The splicing process is divided into distinct sequential steps: preparation of handrail ends, assembly on mandrel, heat treatment with heat paddles, application of adhesive plies, and final bonding. This segmentation allows each step to be optimized independently while ensuring comprehensive bond strength through multiple bonding mechanisms rather than relying on a single complex process.
Solution Approach 2:
The invention uses composite bonding approaches by combining thermal bonding (through heat paddles melting thermoplastic layers) with adhesive bonding (through adhesive plies applied to the joint). This multi-mechanism bonding system creates superior bond strength that neither method could achieve alone, while keeping each individual step relatively simple and well-understood.
2Reliability
If a comprehensive splicing process is implemented to ensure strong and durable bonds, then the reliability of the joint improves, but the manufacturing time and process complexity increase
Solution Approach 1:
The handrail ends are prepared in advance by removing surface material to expose fresh bonding surfaces, and the adhesive plies are pre-positioned on the mandrel before final assembly. This preliminary preparation ensures that when the actual bonding occurs, all components are ready for immediate bonding, reducing overall process time while maintaining comprehensive bonding for high reliability.
Solution Approach 2:
The splicing process is designed as a continuous sequence of operations where each step flows into the next without interruption: preparation → assembly → heating → adhesive application → bonding. This continuous process minimizes idle time between operations while ensuring each bonding mechanism is properly applied, achieving both high reliability and efficient manufacturing.
3Reliability
If multiple bonding mechanisms are used to create a robust spliced joint, then the resistance to failure improves, but the ease of manufacture decreases
Solution Approach 1:
The splicing mandrel serves as an intermediary device that holds all components in precise alignment during assembly. It positions the handrail ends, heat paddles, and adhesive plies correctly, eliminating the need for complex alignment procedures. This intermediary tool simplifies the manufacturing process while enabling the use of multiple bonding mechanisms for enhanced reliability.
Solution Approach 2:
The heat paddles are designed to self-regulate their heating through direct contact with the thermoplastic layers, and the adhesive plies are applied in a way that self-aligns with the joint interface. This self-service approach reduces the skill level and complexity required for manual operation, making the multi-mechanism bonding process easier to manufacture while maintaining high reliability.
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 method results in a strong, durable, and aesthetically pleasing spliced joint that withstands regular use and installation conditions, minimizing the risk of failure and ensuring a smooth operational experience.
Implementation Method 1
heat paddles, and hot air guns to create interweave patterns, weld thermoplastic layers
Implementation Method 2
heat paddles, and hot air guns to create interweave patterns, weld thermoplastic layers
Data Source
Figure 1~2
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Figure 5
AI summary
A handrail has a thermoplastic body having a generally C-shaped cross section, a stretch inhibitor in the thermoplastic body above a T-shaped slot and a slider fabric layer. The handrail includes first and second end portions, each comprising a forward part extending from an end surface of the end portion and a rear part adjacent the forward part. A method of forming a joint can include: providing cuts to separate a top section of the thermoplastic body from a base section including shoulder portions; for each end portion, removing at least shoulder portions from the forward part thereof, to leave a central portion including a forward part at the slider fabric layer and a layer of thermoplastic; cutting the forward parts to a required shape; and assembling the first and second end portions together to form a spliced joint for moulding.