Motorized Curtain Carriage With Split Suspension for Curved Rails

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Solution Overview

Problem

Existing motorized carriages for opening and closing curtains face challenges in maintaining a constant contact force between the friction wheel and the rail, especially when the curtain weight varies, leading to tilting torques and potential sticking issues in curved rail sections.

Innovation Solution

A motorized carriage design featuring a casing with suspension members that only take the constant weight of the casing and its contents, while a cradle with independent suspension members takes the variable curtain weight, allowing for relative movement between the housing and cradle, ensuring a constant contact force and enabling operation on curved rails with a small radius of curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the curtain weight is suspended cantilevered relative to the housing, then the curtain can be effectively supported, but a tilting torque is created on the housing that requires fine adjustment of the contact force between the friction wheel and the rail

Engineering Contradiction:
Improvecontact force between friction wheel and railVSAvoidfine adjustment mechanism
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The invention divides the carriage into two independent parts: a housing containing the motor and friction wheel, and a cradle supporting the curtain. Each part has its own suspension members, which separates the weight support functions and eliminates the tilting torque problem that would otherwise require fine adjustment mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the curtain support function from the housing by introducing a separate cradle with its own suspension members. This removes the source of tilting torque from the housing, eliminating the need for fine adjustment of the friction wheel contact force.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If the carriage is designed to accommodate curved rails with small radius of curvature, then the system becomes more adaptable, but the carriage may get stuck in bends

Engineering Contradiction:
Improveability to follow curved railVSAvoidcarriage movement smoothness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention introduces dynamic capability by allowing relative movement between the housing and cradle through articulated suspension members. This dynamic adjustment enables the carriage to adapt to curved rail geometries while maintaining reliable operation without getting stuck.

Inventive Principle:
Principle #15Dynamics

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

This design maintains a substantially constant contact force between the friction wheel and the rail, reduces tilting torques, and allows the carriage to navigate curved paths effectively, improving the reliability and efficiency of the curtain operation.

Implementation Method 1

a friction wheel driven by an electric motor and intended to be in contact with at least one running surface of the rail

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2819556B1Motor-driven carriage, and blackout equipment including such a carriage
Publication Date: 2016.02.24 SOMFY SAS
  • EP2819556B1 patent drawingFigure 1~7
  • EP2819556B1 patent drawingFigure 2
  • EP2819556B1 patent drawingFigure 3

AI summary

The invention relates to a motor-driven carriage (100) for opening/closing a curtain, including a housing (110) that is provided with two members (124, 126) for suspending the housing from a rail (50), wherein a friction wheel (112), which is driven by an electric motor and which is to contact at least one rolling surface (56, 57) of the rail, is rotatably mounted inside said housing. Said carriage (100) also includes a cradle (150) provided with two other members (155, 156) for suspending the cradle from the rail (50), which are separate from the members (124, 126) for suspending the housing (110), as well as means (153, 154) for coupling to the curtain. The cradle is mounted onto the housing (110) and is driven by the housing when the latter moves along the rail, the housing (110) and the cradle (150) optionally being capable of relative movement therebetween.