Gripper System Four-Bar Linkage Backlash-Free Drive

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Solution Overview

Problem

Existing gripper systems face challenges in achieving high positioning accuracy and a large gripper stroke while maintaining a compact size, as they are often limited by guide elements and suffer from backlash in their drive trains.

Innovation Solution

The gripper system employs a drive train with only rotary and pivotable moving assemblies, featuring a roller gear with an output shaft connected to a drive swivel joint, and a parallelogram gear that allows for a large stroke without guide elements, enabling high dynamics and precision through a backlash-free translation mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If guide elements are used to constrain gripper jaw movement, then positioning accuracy is improved, but gripper stroke is limited

Engineering Contradiction:
Improvepositioning accuracyVSAvoidgripper stroke
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The patent removes guide elements from the drive train, extracting the constraint mechanism that limited stroke. The parallelogram linkage replaces guides while maintaining orientation through its geometric structure, allowing unlimited stroke determined only by system geometry rather than physical guide constraints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes mechanical guide elements with a parallelogram linkage mechanism. This replacement eliminates the need for physical guides while maintaining the gripper jaw's orientation through the inherent geometric properties of the parallelogram structure, which preserves parallelism throughout the range of motion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a compact gripper system is designed, then device complexity is reduced, but achieving large stroke becomes difficult

Engineering Contradiction:
Improvegripper system compactnessVSAvoidgripper stroke
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The patent employs a dynamic parallelogram linkage that maintains its geometric structure while allowing continuous motion. The linkage dynamically adapts its configuration throughout the stroke range, preserving the compact form factor when retracted while enabling extended stroke when actuated, without requiring additional space for guide elements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent resolves the compactness-stroke contradiction by utilizing the rotational dimension of the output shaft and crank mechanism. The linear stroke is generated through rotational motion converted by the parallelogram linkage, allowing compact radial packaging while achieving extended linear travel, effectively trading rotational space for linear stroke.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If a backlash-free drive train is implemented, then positioning accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoiddrive train complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes traditional mechanical drive elements (screw drives, belt drives with backlash) with a direct roller gear to output shaft connection. This substitution eliminates backlash inherent in threaded or belt-driven systems while reducing the number of intermediate components, thereby simplifying the drive train while achieving backlash-free operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts intermediate transmission elements from the drive train, creating a direct connection between the roller gear output shaft and the crank. This removal of intermediate components eliminates potential backlash sources while reducing mechanical complexity, as fewer parts mean fewer interfaces where backlash can occur.

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration allows for a compact gripper system with a large stroke, achieving high positioning accuracy and fine adjustment of the gripper jaw, enabling efficient handling of various object shapes and sizes.

Implementation Method 1

at least one rolling gear and a parallelogram gear, wherein the parallelogram gear has a driven crank mounted in the carrier part in a drive pivot joint

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

to which the crank is attached in the drive pivot joint by frictional and/or positive locking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3960397A1Gripper system with four-bar linkage
Publication Date: 2022.03.02 ZIMMER GUNTHER STEPHAN
  • EP3960397A1 patent drawingFigure 1
  • EP3960397A1 patent drawingFigure 2~3
  • EP3960397A1 patent drawingFigure 4~5

AI summary

The invention relates to a gripper system with a carrier part and at least two gripper jaws adjustable relative to each other, wherein at least one gripper jaw can be driven by an electric motor, at least one rolling gear, and a parallelogram linkage, the parallelogram linkage having a driven crank mounted in the carrier part in a drive pivot joint. At least one rolling gear has an output shaft to which the crank is positively and/or frictionally attached in the drive pivot joint. The present invention develops a gripper system with high positioning accuracy and a large gripper stroke.