Snap-Fit Elevator Door Sill for Anti-Derailment and Safe Access
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Solution Overview
Problem
Existing elevator door sills face issues with high production costs, complexity, maintenance times, and reliability, particularly in preventing derailment and access problems for wheelchairs or walkers, and unintentional dropping of objects.
Innovation Solution
A sill design featuring a base with projecting portions and profiled elements that snap-fit into grooves, providing a guide for door leaves, and an anti-derailment device with a hook-like element to prevent derailment, made from materials like plastic, steel, or aluminum, allowing easy assembly and quick maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If very sturdy, heavy doors are produced to withstand high stresses and prevent derailment, then reliability and safety are improved, but manufacturing costs and device complexity increase significantly
Solution Approach 1:
The door system is divided into separate functional components: a lightweight door leaf and a separate sill with integrated anti-derailment mechanism. The sill acts as an independent safety device that can be manufactured separately and assembled, allowing optimization of each component's function and reducing overall manufacturing complexity.
Solution Approach 2:
The sill serves as an intermediary element between the door leaf and the floor, providing the anti-derailment function through its groove and hook-like element design. This mediator approach allows the safety function to be achieved without making the entire door heavy, as the sill alone provides the constraint mechanism.
2Strength
If conventional sills with multiple bends and different materials are used, then structural integrity is maintained, but production costs and manufacturing complexity increase
Solution Approach 1:
The sill combines multiple functions into a single integrated structure: the base element provides structural support while the profiled elements integrated into it provide both guidance and anti-derailment functions. This merging eliminates the need for separate components and complex assembly operations, reducing production costs.
Solution Approach 2:
The sill is made from a single material (metal or plastic) that provides both structural integrity and the required mechanical properties for the anti-derailment mechanism. This eliminates the need to join different materials, simplifying manufacturing while maintaining strength.
3Object-affected harmful factors
If the groove width is reduced to prevent tripping and improve safety, then access safety is improved, but the guide function for door leaves may be compromised
Solution Approach 1:
The groove cross-section is designed with non-uniform geometry: narrow at the top to prevent tripping hazards, but with profiled elements that create effective guiding surfaces. The local geometry varies to satisfy different requirements at different heights and positions within the groove structure.
Solution Approach 2:
The guidance function is achieved not only through the groove width but also through the vertical dimension via the profiled elements with lips that extend into the groove. This dimensional approach allows effective guidance with a narrow top opening, preventing tripping while maintaining door leaf guidance reliability.
4Ease of operation
If sliders with plastic portions are used in the sill, then ease of operation is improved, but maintenance requirements increase due to wear
Solution Approach 1:
The profiled elements are designed as simple, inexpensive components that can be easily replaced if wear occurs. By making them simple in design and material, the replacement cost and complexity is minimized, effectively treating them as low-cost replaceable parts rather than complex maintenance-intensive components.
Solution Approach 2:
The invention changes the material parameter from plastic (which wears) to metal or durable plastic with different wear characteristics. This parameter change in material selection reduces wear rate and maintenance requirements while preserving the smooth sliding function.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A sill (1) for an elevator door, comprising: - a base (2) extending mainly in a longitudinal direction and comprising a first upper projecting portion (21) and a second upper projecting portion (22) separated by a first groove (23) that is open in an upwards direction; − at least a first profiled element (3) joint-fitted on the first upper projecting portion (21); - a second profiled element (4) joint-fitted on the second upper projecting portion (22); the first profiled element (3) and the second profiled element (4) have respectively a first lip (3a) and a second lip (4a) penetrating into the first groove (23) thus defining a guide for the sliding of a leaf (100) of the elevator door, each lip (3a, 4a) has a free end (13, 14) with an enlarged cross-section which defines a recess counter-shaped to a free end of the 15 corresponding upper projecting portions so that the lip snap-fits on the base.