Lumbar support system

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing lumbar support systems in vehicle seats often suffer from poor efficiency, noise, and require numerous heavy components due to the use of Bowden cables and electromechanical actuators.

Innovation Solution

A lumbar support system utilizing a reversible DC motor, worm gear, and spindle mechanism with oppositely threaded ends to translate sliders along a spindle rail, coupled with flexible cables and hinges for smooth, adjustable lumbar support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a Bowden cable and electromechanical actuator are used to move the lumbar support, then the lumbar support can be adjusted, but the system becomes noisy and requires large, heavy motors

Engineering Contradiction:
Improvelumbar support adjustmentVSAvoidnoise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the traditional electromechanical actuator with a manual crank mechanism. The user directly operates the lumbar support adjustment through a hand crank that winds a cable, eliminating the need for electric motors and reducing noise generation to minimal mechanical friction sounds only.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent removes the electromechanical actuator and motor components from the system entirely. By extracting these noisy components and replacing them with a simple manual cable-winding mechanism, the system achieves quiet operation while maintaining full adjustability functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If a Bowden cable and electromechanical actuator are used to move the lumbar support, then the lumbar support can be adjusted, but the system requires large, heavy motors

Engineering Contradiction:
Improvelumbar support adjustmentVSAvoidmotor weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent removes the heavy electromechanical actuator and motor components from the system. By extracting these weighty components and replacing them with a lightweight manual crank and cable mechanism, the overall system weight is significantly reduced while maintaining full adjustability functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple, inexpensive manual components (crank, cable, pulleys) instead of expensive, heavy electromechanical systems. These simple mechanical parts are lightweight and sufficient for the adjustment function, eliminating the need for large motors.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If a Bowden cable system is used for lumbar support actuation, then the lumbar support can be moved, but the total system efficiency becomes poor

Engineering Contradiction:
Improvelumbar support actuationVSAvoidsystem efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces the inefficient Bowden cable system with a direct cable-winding mechanism. Instead of using a Bowden cable with internal friction and mechanical disadvantage, the user directly winds the cable onto a drum, creating a more efficient mechanical system with fewer energy losses and better force transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Provides efficient, quiet, and adjustable lumbar support with reduced component complexity, enhancing occupant comfort and reducing noise and weight.

Implementation Method 1

a reversible DC motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

worm gear

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 3

worm gear

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 4

spindle mechanism with oppositely threaded ends to translate sliders along a spindle rail

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 5

spindle mechanism

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3745923B1Lumbar support system
Publication Date: 2025.10.22 LEGGETT & PLATT CANADA CO
  • EP3745923B1 patent drawingFigure 1
  • EP3745923B1 patent drawingFigure 2
  • EP3745923B1 patent drawingFigure 3

AI summary

A lumbar support system for a seat backrest includes a fixed frame and a flexmat coupled to the fixed frame. The flexmat includes first and second outer wires and a plurality of transverse wires extending between the outer wires. A support element is coupled to a lower portion of the flexmat below the plurality of transverse wires for concurrent movement with the flexmat from a first position to a second position. The support element is anatomically contoured for lumbar and pelvic support, and the support element is constructed of a more rigid material than the flexmat.