Spindle Drive Backstop Gear for Louvre Window Restoring Forces

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Solution Overview

Problem

Large louvre windows with increased dimensions and weight pose challenges in absorbing restoring forces and moments, which conventional motor-driven spindle drives struggle to compensate without straining the drive motor.

Innovation Solution

A spindle drive with a bidirectional backstop gear that decouples restoring forces and moments from the drive motor, using a mechanism with radially projecting driver projections and grooves, and rolling elements to create a self-locking effect, allowing forces to be absorbed by the housing without motor load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional motor-driven spindle drives are used for large louvre windows, then the drive motor must compensate for large restoring forces and moments, but this leads to motor strain and requires higher performance motors

Engineering Contradiction:
Improveability to absorb restoring forcesVSAvoidmotor performance requirement
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent extracts the function of absorbing restoring forces from the drive motor by introducing a separate backstop gear mechanism. The backstop gear is decoupled from the motor, allowing it to independently absorb restoring forces and moments generated by large louvre windows, thereby preventing motor strain and enabling the use of lower performance motors.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If the driver groove width is larger than the driver projection width, then bidirectional rotation is enabled, but this creates angular play between elements

Engineering Contradiction:
Improvebidirectional rotation capabilityVSAvoidangular precision
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the backstop gear selectively lockable in both rotational directions. The mechanism transitions between locked and unlocked states dynamically: during normal operation the groove width allows angular play for bidirectional rotation, while during locking the rolling bodies engage with the guide surface to eliminate play and prevent reverse rotation under load.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a backstop gear is introduced to prevent restoring forces from feeding back into the motor, then the motor is decoupled from restoring forces, but this adds device complexity

Engineering Contradiction:
Improveprotection against motor strainVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the backstop gear mechanism with the existing threaded spindle and spindle nut assembly. The backstop gear shares the same rotational axis and spatial envelope as the spindle, integrating multiple functions (motor decoupling, bidirectional locking, and force absorption) into a compact unified structure rather than adding separate independent components.

Inventive Principle:
Principle #5Merging (Combining)

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 spindle drive effectively absorbs restoring forces and moments without straining the drive motor, providing robust and reliable locking against burglary and enabling the use of high-efficiency threaded spindles, leading to size and cost savings in motor gear units and power supplies.

Implementation Method 1

at least one rolling body is arranged, which is arranged in the cutout between the inner surface of the guide and a surface of the element having the driving groove

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The backstop gear therefore decouples the drive motor from such a restoring force or such a restoring torque

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3833841B1Spindle drive having a reverse-lock transmission
Publication Date: 2023.10.25 DH MECHATRONIC
  • EP3833841B1 patent drawingFigure 1~2
  • EP3833841B1 patent drawingFigure 3~4
  • EP3833841B1 patent drawingFigure 5

AI summary

The invention relates to a further development of a spindle drive (1), and to a lamellar window or a lamellar flap having a spindle drive for moving lamellar elements such that occurring restoring forces and restoring torques can be intercepted better, and in particular without stressing the drive motor. For this purpose, the spindle drive (1) has a specially designed reverse-lock transmission (6) arranged between a drive shaft of a drive motor (3) and a threaded spindle (4).