Harmonic Drive Digital Register for Backlash-Free High Torque

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Solution Overview

Problem

Conventional systems for adjusting registration between rotating rolls in corrugated box machines suffer from backlash in gearing and inaccurate motor control, leading to unacceptable accuracy for modern box-making standards, and require gear train modifications when using single harmonic drives, which reduces torque capacity.

Innovation Solution

A digital register system utilizing a one-to-one ratio torque configuration with harmonic drives and a split coupling, eliminating the need for gear ratio modifications, and incorporating a motor with an encoder for precise rotation control, achieving high torque handling and reduced maintenance by eliminating slip rings and commutators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional slip ring motor and gearing systems are used for registration adjustment, then the system structure is simple, but backlash in the gearing and inaccurate motor control make registration accuracy unacceptable

Engineering Contradiction:

Improveregistration accuracyVSAvoidsystem structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical slip ring motor and gearing system with a digital motor system that uses harmonic drives. This substitution eliminates the problematic backlash-prone conventional gearing while providing precise digital control for registration adjustment, directly resolving the contradiction between accuracy and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters by transitioning from analog slip ring motor control to digital motor control with encoders. This parameter change enables precise measurement and adjustment of registration while using harmonic drives to achieve the required torque without conventional gearing, thus improving accuracy without excessive complexity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If single harmonic drives are used to improve registration accuracy, then accuracy improves, but gear train modification is required and torque capacity is reduced

Engineering Contradiction:

Improveregistration accuracyVSAvoidtorque capacity

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The patent merges two harmonic drives in a tandem configuration to achieve the desired -1:1 ratio while maintaining high torque capacity. This combination allows the system to benefit from the accuracy of harmonic drives without the torque reduction associated with single harmonic drive configurations, and eliminates the need for gear train modifications.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite approach by combining two harmonic drive units with specific ratios (+1 and -1) to create an overall -1:1 ratio system. This composite configuration leverages the advantages of harmonic drives while compensating for individual unit limitations, maintaining both accuracy and torque capacity.

Inventive Principle:

Principle #40Composite materials

3Force

If conventional gearing systems are used, then torque capacity is maintained, but backlash reduces registration accuracy

Engineering Contradiction:

Improvetorque capacityVSAvoidregistration accuracy

Core Design Contradiction:

ForceVSMeasurement precision

Solution Approach 1:

The patent substitutes conventional gearing systems with harmonic drives that inherently eliminate backlash through their unique mechanical engagement. This substitution maintains torque capacity while dramatically improving registration accuracy by eliminating the backlash present in conventional gear systems.

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

The system provides precise registration with high accuracy and increased torque capacity, up to 26,600 inch-pounds, while simplifying maintenance and avoiding the need for gear ratio adjustments, thus meeting modern box-making standards.

Implementation Method 1

incorporating a motor with an encoder for precise rotation control

Methodology Applied

Scientific EffectEncoder:

Data Source

PatentUS11215270B1One-to-one ratio high-torque digital register for industrial machinery

Publication Date: 2022.01.04 THACKER IND SERVICE CO

AI summary

A system and method for registration of rotary drive shaft in a high-torque environment. The system utilizes a pair of connected harmonic drives to allow the clocking or registration of the rotary drive shaft without backlash and without requiring gearing changes as a result of a single harmonic drive. The pair of connected harmonic drives is coupled together by a tandem coupling.