Elevator Counterweight Screen Sandwich Composite Panel

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Solution Overview

Problem

Existing counterweight screens in elevator systems face challenges in achieving high stiffness while minimizing weight and cost, particularly with reduced clearance requirements, as increasing stiffness through traditional methods like sheet metal bends or separate stiffeners leads to increased weight, cost, and space issues.

Innovation Solution

A sandwich-structured composite panel is used for the counterweight screen, comprising face skins and a core, where the face skins can be made of sheet metal or polymer, and the core can be a honeycomb, micro lattice, or metallic foam structure, providing high stiffness with reduced thickness and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If stiffness of the counterweight screen is increased by using sheet metal bends or pressed/roll formed grooves, then the stiffness requirement is met, but the weight and cost of the counterweight screen increase

Engineering Contradiction:

ImprovestiffnessVSAvoidweight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The counterweight screen is constructed as a sandwich-structured composite panel consisting of two face skins (metal or polymer) and a core (foam, honeycomb, or micro lattice structure). This composite construction provides high stiffness and strength while maintaining low weight, as the core material provides structural support without adding significant mass compared to traditional solid sheet metal solutions.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The core of the sandwich panel uses porous or cellular structures such as foam, honeycomb, or micro lattice patterns. These porous materials provide excellent stiffness-to-weight ratios, allowing the counterweight screen to meet stiffness requirements while minimizing weight. The void structures within the core material distribute loads effectively without requiring heavy solid construction.

Inventive Principle:

Principle #31Porous materials

2Strength

If stiffness is increased by separate stiffeners (profiles or flat sheet metals), then the stiffness requirement is met, but the weight and cost increase significantly and installation complexity increases

Engineering Contradiction:

ImprovestiffnessVSAvoidinstallation complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The stiffening function is merged into the core structure of the sandwich panel itself. The core (foam, honeycomb, or micro lattice) is integrated between the face skins to provide inherent stiffening, eliminating the need for separate stiffeners. This integration simplifies the overall structure, reduces installation complexity, and lowers cost while maintaining the required stiffness.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If total thickness is increased to improve stiffness, then the stiffness requirement is met, but the clearance between car and counterweight is reduced

Engineering Contradiction:

ImprovestiffnessVSAvoidclearance

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The use of porous core materials (foam, honeycomb, micro lattice) provides high stiffness with minimal thickness. The cellular structure of the core material delivers excellent structural performance without requiring thick construction, thereby maintaining adequate clearance between the car and counterweight while meeting stiffness requirements.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The sandwich-structured composite panel achieves high stiffness-to-thickness ratio through the combination of face skins and a lightweight core. This allows the counterweight screen to be made thinner compared to traditional solid sheet metal constructions, preserving the necessary clearance space in the elevator shaft.

Inventive Principle:

Principle #40Composite materials

4Strength

If pressed or roll formed stiffening forms are used, then stiffness is improved, but the volume is reduced and pressing tooling cost increases significantly

Engineering Contradiction:

ImprovestiffnessVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The core material (foam, honeycomb, or micro lattice) is manufactured using cost-effective processes that do not require complex pressing tooling. These porous structures can be produced through extrusion, molding, or assembly of modular units, significantly reducing tooling costs compared to traditional pressed or roll-formed metal stiffening solutions.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The sandwich panel construction allows the core to be manufactured separately using economical processes and then assembled between face skins. This modular approach avoids the need for expensive pressing tooling while achieving the required stiffness, making the overall solution more cost-effective to manufacture.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10919731B2Elevator system and counterweight screen

Publication Date: 2021.02.16 KONE OYJ

AI summary

An elevator system comprising a shaft having a pit, a car guided by a pair of first guide rails to be vertically movable in the shaft, a counterweight connected to the car by a suspension rope, the counterweight being guided by a pair of second guide rails to be vertically movable in the shaft, and a counterweight screen in a space between the counterweight and the car, the counterweight screen being attached to the second guide rails at the pit. The counterweight screen is a sandwich-structured composite panel.