Variable Mass Elevator Counterweight for Load Adaptation

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Solution Overview

Problem

Elevator systems with fixed counterweights waste energy and experience high motor wear when the load is less than the duty load, as the counterweight's mass is optimized for half the duty load, leading to excessive torque and unnecessary energy consumption.

Innovation Solution

A variable mass elevator counterweight system that adjusts its mass by attaching or detaching additional parts or adding/removing fluid-like materials, allowing the counterweight mass to match the current load conditions, reducing energy consumption and wear by optimizing the counterweight mass in real-time based on load variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a fixed mass counterweight is used to balance the elevator car, then the motor torque is reduced for maximum load conditions, but energy consumption and motor wear increase when the load is less than maximum

Engineering Contradiction:
Improvemotor torqueVSAvoidenergy consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The counterweight mass is made variable through a container that can add or remove fluid-like material (water, sand, or granular material) based on the actual load in the elevator car. This dynamic adjustment allows the counterweight to match the car mass plus load mass in real-time, optimizing motor torque requirements and reducing energy consumption when the load is less than maximum.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mass parameter of the counterweight is changed by varying the amount of fluid-like material in the container. The system monitors the load mass and adjusts the counterweight mass accordingly, transforming the fixed mass system into a variable mass system that adapts to different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a fixed mass counterweight is selected for maximum load, then the counterweight balances the car at full capacity, but creates excessive torque and wear when transporting lighter loads

Engineering Contradiction:
Improvemotor wearVSAvoidmotor torque
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The counterweight system dynamically adjusts its mass to match the actual load conditions, preventing excessive torque and motor wear during light load operations while maintaining proper balance at maximum load capacity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses load sensing to provide feedback on the actual mass being transported, which then controls the addition or removal of fluid-like material from the counterweight container, creating a closed-loop system that optimizes motor torque and reduces wear.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the counterweight mass is reduced to match light loads, then energy consumption decreases, but the counterweight becomes insufficient for maximum load conditions

Engineering Contradiction:
Improveenergy consumptionVSAvoidload range
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The counterweight mass is dynamically adjusted based on the actual load, allowing the system to operate efficiently across the full range of load conditions from empty car to maximum duty load, rather than being optimized for a single fixed load condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The counterweight system serves multiple functions: it provides proper balance at maximum load, reduces energy consumption at light loads, and adapts to any intermediate load condition, making it universally effective across all operating scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If a variable mass counterweight system is implemented, then energy consumption and motor wear are reduced, but device complexity increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidcounterweight structure
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The system uses hydraulic or pneumatic mechanisms to add or remove fluid-like material from the counterweight container, providing a relatively simple and reliable method for mass adjustment compared to mechanical addition/removal of solid counterweight blocks.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system changes the physical state or amount of material in the container to vary the counterweight mass, using readily available materials like water, sand, or granular material that can be easily added or removed through simple openings or valves.

Inventive Principle:
Principle #35Parameter changes

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 system reduces energy consumption and motor wear by dynamically adjusting the counterweight mass to match load conditions, improving operational efficiency and environmental sustainability.

Implementation Method 1

The suspension member suspends an elevator counterweight, on one side of the motor, and suspends an elevator car on the other side of the motor. The counterweight mass is varied by adding or removing a mass, wherein the mass is added to or removed from a container.

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4219379B1Elevator counterweight having a variable mass
Publication Date: 2025.03.26 OTIS ELEVATOR CO
  • EP4219379B1 patent drawingFigure 1
  • EP4219379B1 patent drawingFigure 2
  • EP4219379B1 patent drawingFigure 3

AI summary

An elevator counterweight (2) includes a first part (4). The first part (4) is configured to be connected, in use, to a suspension member (8) of an elevator system (1). The first part (4) is arranged to receive an additional mass (6) when the first part (4) is connected to the suspension member (8), such that a mass of the elevator counterweight (2) can be varied. A controller (14) may be arranged to control a mass variation system (12) to vary the mass of the elevator counterweight (2) according to a schedule. The controller (14) may determine the schedule in a learning process.