Paper Sheet Storage Drum with Differential Torque for Equal Tape Tension

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Solution Overview

Problem

Existing sheet storage devices face issues with unequal tensions on tapes due to non-uniform drum diameters, leading to sheet displacement and potential jamming, which are not adequately addressed by configurations with torque limiters.

Innovation Solution

A sheet storage device with a first and second differential mechanism, utilizing planetary and bevel gears, distributes torque evenly to reels to maintain consistent tape tensions, even with non-uniform drum diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a torque limiter is attached to each tape reel to equalize tensions, then tension equalization is improved, but device complexity increases due to the large number of torque limiters required

Engineering Contradiction:
Improvetension equalizationVSAvoidnumber of torque limiters
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the tension equalization function from multiple individual torque limiters into a single differential mechanism that serves all tape reels simultaneously. This single mechanism distributes torque evenly to multiple reels, achieving the same tension equalization effect without requiring separate torque limiters for each reel, thereby reducing device complexity while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The differential mechanism is designed to perform multiple functions: it serves as both the torque transmission device for driving the tape reels and the tension equalization device simultaneously. This multi-functional design eliminates the need for separate torque limiter components at each reel, reducing overall device complexity while maintaining effective tension control across all tapes

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Quantity of substance

If the drum diameter is made large to accommodate sheets, then storage capacity is improved, but manufacturing precision deteriorates due to non-uniform drum diameter causing unequal tape tensions and sheet displacement

Engineering Contradiction:
Improvestorage capacityVSAvoiddrum diameter uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The differential mechanism acts as a mechanical feedback system that automatically compensates for variations in drum diameter. When the drum diameter is non-uniform, causing different winding speeds at different radial positions, the differential mechanism detects this through the motion of its components and automatically adjusts torque distribution to maintain equal tensions on all tapes, thereby preventing sheet displacement despite manufacturing imperfections

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention changes the parameter of torque distribution dynamically through the differential mechanism. Instead of applying fixed torque to each reel, the system allows torque parameters to vary and self-adjust based on the actual winding conditions, enabling the system to accommodate large drum diameters and their inherent non-uniformities while maintaining precise tension control

Inventive Principle:
Principle #35Parameter changes

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 solution effectively equalizes tensions on multiple tapes, preventing sheet displacement and ensuring stable winding and unwinding operations.

Implementation Method 1

a first differential mechanism that is provided in a torque transmission path for transmitting torque to the first reel, the second reel, and the third reel, and that distributes the torque input from the torque source to a first path and a second path; and a second differential mechanism that is provided in the second path and distributes the torque which has been distributed by the first differential mechanism to a third path and a fourth path

Methodology Applied
Scientific EffectDifferential mechanism: Gear

Data Source

PatentEP3862983B1Paper sheet storage device
Publication Date: 2025.08.13 GLORY LTD
  • EP3862983B1 patent drawingFigure 1
  • EP3862983B1 patent drawingFigure 2
  • EP3862983B1 patent drawingFigure 3

AI summary

A sheet storage device is provided with a first reel (361), a second reel (362), a third reel (363), a shaft (360), a drum (37), a torque source (electric motor 36) for generating torque so that predetermined tension is generated on a tape during the rotation of the drum, a first differential mechanism (61) for distributing torque to a first path and a second path, and a second differential mechanism (62) provided in the second path and distributing the torque, which has been distributed by the first differential mechanism, to a third path and a fourth path. The first reel is located in the first path, the second reel is located in the third path, and the third reel is located in the fourth path.