Screen Drive Compensation Spring Noise Reduction

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Solution Overview

Problem

Conventional screen drive systems for roll-up screens experience high electrical consumption during the rolling up process due to substantial efforts required, and compensation springs used to reduce torque variability often generate noise due to metal/metal contact within limited radial space.

Innovation Solution

Incorporating plastic rods between turns of the compensation spring to prevent noisy metal/metal contact, with the rods having an external radius greater than the spring's maximum external radius, ensuring a plastic/metal contact that reduces noise and maintains stability within the limited space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If compensation spring is installed around the actuator inside a winding tube, then the radial space is utilized efficiently, but noise is generated due to contact between the coils of the spring and the actuator or winding tube

Engineering Contradiction:
Improveradial space utilizationVSAvoidnoise
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

A plastic rod is introduced as an intermediary element between the compensation spring and the winding tube/actuator. The rod has an external radius greater than the maximum external radius of the compensation spring, preventing direct contact between the spring coils and metallic surfaces. This mediator eliminates noise-generating metal/metal contact while maintaining compact radial dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the compensation spring is stretched to provide space for its fully wound configuration, then sufficient space is available, but the spring becomes unstable and generates noise

Engineering Contradiction:
Improvespace for spring configurationVSAvoidspring stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The plastic rod serves as a stable intermediary that defines the maximum radial extent of the spring without requiring the spring itself to be stretched. The rod maintains a fixed position with radius greater than the spring's maximum radius, providing stable spatial boundaries while preventing the spring from contacting metallic surfaces and becoming unstable.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If conventional compensation springs are used to reduce torque variability, then electrical consumption is reduced, but metal/metal contact generates noise

Engineering Contradiction:
Improveelectrical consumptionVSAvoidnoise
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The solution combines metallic compensation spring material with plastic rod material. The composite structure uses the metallic spring for torque compensation functionality while the plastic rod provides noise-free contact surfaces. This composite approach maintains the energy-saving benefits of the metallic spring while eliminating the harmful noise through material property differences.

Inventive Principle:
Principle #40Composite materials

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 effectively reduces noise and maintains system stability by avoiding metal/metal contact, allowing for efficient operation with minimal electrical consumption and compact design.

Implementation Method 1

an external radius of said at least one rod is greater than a maximum external radius of the compensation spring

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3821103B1Drive system driving a screen, and apparatus comprising such a system
Publication Date: 2022.11.30 SOMFY ACTIVITES SA
  • EP3821103B1 patent drawingFigure 1
  • EP3821103B1 patent drawingFigure 2~3
  • EP3821103B1 patent drawingFigure 4

AI summary

Disclosed is a drive system driving a screen, comprising an actuator for rotationally driving a winding tube (5) acting on the screen, and a compensation spring (7) which is mounted around the actuator (3) and has several turns (70, 71) formed by winding a wire. The drive system comprises at least one plastic ring (9) that is placed between two adjacent turns (70, 71) of the compensation spring (7), and an outer radius (R94) of the ring (9) is larger than a maximum outer radius (R8) of the compensation spring (7).