Escalator Step Tread Element Fixing via Interference Fit

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing escalator and moving walkway steps/pallets face challenges in production cost, noise due to vibrations, and operational safety issues related to elastic intermediate layers that can settle or decompose, along with complex assembly processes.

Innovation Solution

A design featuring a support body with fastening projections on the underside of tread elements that protrude through openings in the base, allowing for secure fixation without an elastic intermediate layer, using a fixing element that generates prestressing force for secure attachment and easy assembly, and potentially incorporating adhesive for vibration damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If spring elements are used between tread elements and supporting body to allow relative movement, then ease of assembly is improved, but noise is generated due to vibrations and shocks at resonant frequency

Engineering Contradiction:
Improveease of assemblyVSAvoidnoise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent removes the spring element from the system entirely. Instead of using a spring element to allow relative movement, the invention uses a rigid connecting element that directly connects the tread element to the supporting body, eliminating the source of vibration-induced noise while maintaining assembly simplicity through the press-fit mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harm of rigid connection (inability to absorb shocks) into a benefit by using a press-fit mechanism with interference fit. The rigid connecting element is inserted with slight interference into the tread element and supporting body, creating a rigid connection that prevents noise-generating vibrations while the friction from interference fit provides sufficient shock absorption.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If damping elements are used between footplates and supporting body to reduce noise, then noise is reduced, but the elements are rubbed and decomposed by lubricants and repeated loading

Engineering Contradiction:
ImprovenoiseVSAvoiddurability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent removes the damping element from the system entirely. Instead of using a separate damping element that is susceptible to lubricant degradation and mechanical wear, the invention achieves vibration damping through the friction generated by the interference fit of the rigid connecting element, eliminating the reliability issues associated with separate damping elements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite connection system combining mechanical interference fit with friction-based damping. The rigid connecting element utilizes interference fit between its outer surface and the holes in the tread element and supporting body, creating a composite mechanical connection that provides both rigid support and vibration damping through friction, without requiring separate damping materials.

Inventive Principle:
Principle #40Composite materials

3Reliability

If threaded projections with nuts are used to fix tread elements, then reliability is improved, but device complexity and assembly difficulty increase

Engineering Contradiction:
Improvefixation reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the threaded projection and nut assembly from the system. Instead of using external fasteners that require threading and nut installation, the invention uses a press-fit rigid connecting element with interference fit that is directly inserted into the tread element and supporting body, dramatically simplifying the assembly process while maintaining secure fixation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the threaded mechanical fastening system with a press-fit interference fit mechanism. The rigid connecting element is inserted with slight interference into the holes of the tread element and supporting body, creating a friction-based mechanical connection that eliminates the need for threads, nuts, and complex fastening operations while maintaining reliable fixation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If one-piece casting or extrusion is used to manufacture steps or pallets, then manufacturing precision is improved, but production cost and mold complexity increase significantly

Engineering Contradiction:
Improvestructural integrityVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent divides the step or pallet into separate components: the supporting body and the tread element. The rigid connecting element serves as a separate fastening component that connects these parts. This segmentation allows each component to be manufactured independently using simpler, less expensive processes while maintaining the structural integrity of the complete assembly through the interference fit connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a rigid connecting element as an intermediary component between the supporting body and the tread element. This intermediate piece facilitates the connection between the two main components through interference fit, allowing modular assembly while reducing the manufacturing complexity and cost associated with producing large, complex one-piece structures requiring expensive molds and extensive machining.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3099617B1Pallet for a moving walkway or step for an escalator
Publication Date: 2018.02.07 INVENTIO AG
  • EP3099617B1 patent drawingFigure 1~2
  • EP3099617B1 patent drawingFigure 3~4
  • EP3099617B1 patent drawingFigure 5~6

AI summary

The invention relates to a step of an escalator or to a pallet (14) of a moving walkway (11). The step or pallet (14) has a support body (30) having a base (31) and at least one tread element (40) having a tread surface (41), wherein the at least one tread element (40) has at least one attachment protrusion (43) on an underside (42) facing away from the tread surface (41). In the assembled state, the at least one attachment protrusion (43) protrudes through an opening (34) formed in the base (31). On the side (35) of the base (31) facing away from the tread element (40), at least one fixing element (60) is arranged at least partially between the base (31) and the attachment protrusion (43). The tread element (40) is fixed by the fixing element (60) in a pretensioned manner against the base (31).