Electrosensitive Strip Lift Door Safety Mechanism

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Solution Overview

Problem

Existing safety devices for lift doors, such as those using capacitive panels, tilting section bars, and miniature switches, are complex, expensive, and require precise assembly, making them costly and difficult to maintain, while they aim to prevent fingers from getting caught between doors and jambs during opening.

Innovation Solution

A safety device featuring electrosensitive strips, orthogonally developed from the base, applied to the jambs and doors, which are electrically connected to the lift system control board, using an infrared transmission system to detect deformation and interrupt door movement upon contact, thus preventing fingers from getting caught.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional safety devices with miniature switches and tilting section bars are used, then finger safety is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvefinger safetyVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical safety system (section bars, hinges, miniature switches) with an electrosensitive strip that detects finger contact through electrical or capacitive sensing. This substitution eliminates complex mechanical components while maintaining safety functionality, directly resolving the contradiction between reliability and device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrosensitive strip is implemented as a thin, flexible sensing element that can be applied directly to the door surface. This thin-film approach replaces bulky mechanical components with a sleek, integrated sensor that maintains finger safety without adding device complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If traditional safety devices with miniature switches and section bars are used, then finger safety is improved, but manufacturing and maintenance cost increase

Engineering Contradiction:

Improvefinger safetyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The electrosensitive strip is a relatively inexpensive component compared to traditional mechanical safety devices with multiple moving parts and precision switches. The simplified construction using thin-film sensors and basic electrical connections reduces both manufacturing and maintenance costs while maintaining safety effectiveness.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By replacing expensive mechanical components (hinged section bars, precision miniature switches) with an electrosensitive strip system, the patent significantly reduces manufacturing complexity and cost. The electrical sensing mechanism requires fewer precision-machined parts and assembly steps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional safety devices with miniature switches are used, then finger safety is improved, but assembly precision requirements increase

Engineering Contradiction:

Improvefinger safetyVSAvoidassembly precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The electrosensitive strip eliminates the need for precision mechanical alignment required by miniature switches and hinged section bars. The electrical or capacitive sensing mechanism is inherently more tolerant of positioning variations, significantly reducing assembly precision requirements while maintaining safety functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The flexible nature of the electrosensitive strip allows it to conform to slight variations in installation positioning without compromising sensor effectiveness. This flexibility reduces the stringency of assembly precision requirements compared to rigid mechanical components.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution provides a reliable, cost-effective, and easy-to-install safety device that effectively prevents finger injuries by interrupting door movement upon contact, ensuring safety without complex components and precise assembly requirements.

Implementation Method 1

at least one electrosensitive strip with middle edge orthogonally developed from the base, vertically extended on at least one of the jambs and/or doors and electrically wired to the cage door control board or to the lift system control board

Methodology Applied

Scientific EffectElectrosensitive detection: Conduction (electrical)

Data Source

PatentEP1770046B1Safety device for lift doors

Publication Date: 2013.09.25 SEMATIC SPA

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AI summary

A safety device for lift doors and sliding doors or shutters in general, electrically powered, specially suited to avoid the danger of having one's fingers being caught in between the lift doors (12-14) and the respective jambs (10) or between the two doors while the latter are opening, of telescopic or central opening type, with glass or crystal (16) with a frame (18) or of a different type, includes at least one electrosensitive strip (20) with middle edge (26) orthogonally developed from the base, vertically extended on at least one of the jambs (10) and/or doors (12) and/or (14) and electrically wired to the cage door control board or to the lift system control board or indirectly connected to e.g. an infrared transmission system.