Master-Slave Shaft Assembly for Synchronized Fire Door Barrels

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Solution Overview

Problem

Existing drive systems for rolling curtains/doors face limitations in spanning large openings due to barrel deflection, requiring multiple motors and synchronization, which is costly and inefficient.

Innovation Solution

A master/slave shaft arrangement using a single motor to drive multiple staggered barrels, where a synchronizing shaft synchronizes the rotational driving of the master drive barrel with slave barrels, eliminating the need for individual motors for each barrel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a single long barrel is used to span large openings, then the span width is improved, but barrel deflection increases excessively

Engineering Contradiction:
Improvespan widthVSAvoidbarrel deflection
Core Design Contradiction:
Length of stationary objectVSStability of the object's composition

Solution Approach 1:

The single long barrel is divided into multiple shorter barrels (master barrel and slave barrels) that are staggered along the span. Each barrel has a manageable length that prevents excessive deflection, while collectively they cover the full opening width. The master barrel is driven by a motor and transfers rotation to slave barrels through coupling assemblies, enabling segmented support across large spans.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If multiple barrels are used in staggered configuration, then barrel deflection is reduced, but the number of motors and synchronization complexity increases

Engineering Contradiction:
Improvebarrel deflectionVSAvoidmotor synchronization
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Multiple barrels are merged into a single synchronized system where one motor drives the master barrel, which in turn drives all slave barrels through mechanical coupling. This eliminates the need for multiple independent motors and their associated synchronization controls, reducing device complexity while maintaining the benefits of multiple staggered barrels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The master barrel acts as an intermediary between the single motor and the slave barrels. It receives rotational drive from the motor and transfers it to slave barrels through coupling assemblies, enabling synchronized operation without requiring direct motor control of each slave barrel.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If barrel diameter is increased to reduce deflection, then structural stability is improved, but the cost and space requirements increase

Engineering Contradiction:
Improvebarrel deflectionVSAvoidbarrel material
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

Instead of using one or two very large diameter barrels, the system segments the span into multiple smaller diameter barrels. Each barrel has sufficient stiffness for its shorter length, achieving comparable or better overall stability without the material cost and space requirements of larger diameter barrels.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUSRE50140E1Master/slave shaft assembly for fire door and curtain
Publication Date: 2024.09.24 MCKEON ROLLING STEEL DOOR CO INC
  • USRE50140E1 patent drawing
  • USRE50140E1 patent drawing
  • USRE50140E1 patent drawing

AI summary

A master/slave shaft arrangement includes: a motor having an output shaft; a master drive barrel, the first end of which being rotationally driven by the output shaft of the motor, the master drive barrel having, at a second end thereof, a master drive sprocket; a synchronizing shaft that is rotationally driven at its second end by a first coupling assembly, the rotational driving of the synchronizing shaft being synchronous with the rotational driving of the master drive barrel by the motor; and a slave barrel, the slave barrel being rotationally driven at its first end by a second coupling assembly that rotationally couples the synchronizing shaft with the slave barrel to rotationally drive the slave barrel, the rotational driving of the slave barrel being synchronous with the rotational driving of the synchronizing shaft and the rotational driving of the master drive barrel by the motor.