Furniture Drive Rack Mechanism With Variable Gear Contact

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Solution Overview

Problem

Existing drive devices for furniture movable parts lack the ability to provide a variable drive mechanism, limiting the flexibility and efficiency of movement.

Innovation Solution

A drive device comprising a housing, an actuator, a first rack, a second rack, and a toothed actuating element with adjustable contact force angles, allowing the first rack to move along a curved path, and a measuring gear to detect its position, enabling variable drive and precise control of the movable part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a stationary gearwheel with constant base circle diameter is used, then the drive mechanism is simple, but the drive of the movable part cannot be varied

Engineering Contradiction:
Improvevariable drive capabilityVSAvoiddrive mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the base circle diameter of the gearwheel variable rather than constant. The gearwheel is designed with a variable base circle diameter that changes as the rack moves along its path, enabling the drive characteristics to vary dynamically during operation. This resolves the contradiction by providing variable drive capability without requiring multiple separate drive mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the base circle diameter of the gearwheel as a functional parameter that changes with rack position. This allows the drive ratio and mechanical characteristics to be adjusted continuously during operation, achieving adaptable drive behavior while using a single integrated gearwheel structure rather than multiple fixed-parameter components.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the contact force line angle is variable, then the drive efficiency is improved, but the positioning precision becomes more difficult

Engineering Contradiction:
Improvedrive efficiencyVSAvoidpositioning precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies feedback by incorporating a measuring gear that detects the rack position and provides information about the variable base circle diameter. This feedback mechanism allows the system to compensate for the variable contact force line angle, maintaining positioning precision despite the changing drive characteristics. The feedback enables real-time adjustment or compensation to preserve accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces pure mechanical positioning with a combination of mechanical drive and measurement systems. The measuring gear substitutes for simple mechanical stops or fixed positioning elements, using detection and measurement to maintain precision in the presence of variable drive characteristics. This substitution allows the system to achieve both variable efficiency and maintained precision.

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

Enables variable and efficient movement of furniture parts by adjusting contact forces and positions, enhancing the flexibility and control of movable parts like doors and drawers.

Implementation Method 1

A threaded rod of the actuator can be rotatable about a rotational axis. A threaded element can engage with a thread of the threaded rod with a counter thread, so that when the threaded rod rotates, the threaded element is displaced along the movement axis.

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a measuring gear can be rotatably mounted on the housing and engage with a measuring section of the toothing of the first rack. The measuring gear can have a constant base circle diameter. The measuring gear can be configured to detect the position of the first rack.

Methodology Applied
Scientific EffectGear engagement: Gear

Implementation Method 3

a toothed actuating element that engages with the first rack and the second rack and is connectable to the movable part of the furniture

Methodology Applied
Scientific EffectRack and pinion engagement: Rack and Pinion

Implementation Method 4

A first position range of the first rack can be limited on one side by positioning the first rack in the first end position. The angle between the first contact force line and the movement axis in the first position range can increase with increasing distance of the first rack from the first end position.

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP4471244B1Drive device for moving a movable part of a piece of furniture and piece of furniture with such a drive device
Publication Date: 2025.07.30 FLAP COMPETENCE CENT KFT
  • EP4471244B1 patent drawingFigure 1
  • EP4471244B1 patent drawingFigure 2
  • EP4471244B1 patent drawingFigure 3

AI summary

Drive device for moving a movable part of a piece of furniture, comprising: a housing (2) that can be connected to a body of the furniture; an actuator (7) that is connected to the housing (2); a first rack (11) that can be moved by the actuator (7) along an axis of movement (B) between a first end position and a second end position; a second rack (14) that is fixedly connected to the housing (2); and a toothed actuating element (16) that engages with the first rack (11) and the second rack (14) and can be connected to the movable part of the furniture.