Self-Compensating Jaw Guides for Gripper Precision

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Solution Overview

Problem

Parallel grippers face challenges in maintaining predictability and repeatability due to manufacturing tolerances causing running clearances between jaws and guide surfaces, which affect the precision and reliability of jaw motion in high-precision applications.

Innovation Solution

The implementation of self-compensating jaw guides with longitudinally extending wedges and springs that reduce running clearance by biasing the wedges towards the jaws, ensuring a more predictable and repeatable jaw motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional guide surfaces are used with standard manufacturing tolerances, then the gripper structure is simple and easy to manufacture, but running clearance develops between jaws and guide surfaces, reducing predictability and repeatability of jaw motion

Engineering Contradiction:
Improvejaw motion predictabilityVSAvoidguide structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A compensating jaw guide is introduced as an intermediary element between the jaw and the guide surface. This compensating guide features a tapered surface that interfaces with both the jaw and the main guide surface, acting as a mediator that eliminates running clearance while maintaining the overall guide structure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The compensating jaw guide utilizes a tapered surface geometry instead of a flat guide surface. This parameter change in the guide surface shape allows the jaw to be positioned and maintained in precise alignment, eliminating running clearance through the geometric design rather than relying on tight manufacturing tolerances

Inventive Principle:
Principle #35Parameter changes

2Reliability

If running clearance is reduced through tighter tolerances, then jaw motion predictability improves, but manufacturing cost and difficulty increase

Engineering Contradiction:
Improvejaw motion repeatabilityVSAvoidguide surface manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The compensating jaw guide serves as an intermediary component that absorbs the effects of manufacturing tolerances. By introducing this intermediate element, the system achieves high reliability in jaw motion repeatability without requiring the main guide surfaces to be manufactured with excessively tight tolerances

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide system is segmented into multiple components: the main guide surface and the compensating jaw guide. This segmentation allows each component to be manufactured within standard tolerances while the assembly of these components together achieves the cumulative effect of high precision and repeatability

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If standard jaw guides are used, then the gripper structure remains simple, but frictional forces increase and jaw path deviation occurs under external forces

Engineering Contradiction:
Improvejaw path stabilityVSAvoidjaw guide structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The compensating jaw guide employs a tapered surface geometry that fundamentally changes the contact mechanics between the jaw and guide. This parameter change reduces frictional forces and prevents jaw path deviation under external forces by maintaining consistent contact and alignment throughout the jaw's range of motion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The compensating jaw guide acts as a mediator that maintains stable jaw path under external forces. It provides a controlled interface that prevents the jaw from deviating from its intended path, even when subjected to lateral loads or moments during gripping operations

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution minimizes running clearance, enhancing the precision and reliability of jaw motion, reducing frictional forces and maintaining the desired path of jaw movement even under external forces and moments, thus improving the gripper's performance in high-precision manufacturing and handling applications.

Implementation Method 1

spring biases the wedge toward the jaw

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

reducing frictional forces and maintaining the desired path of jaw movement

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP2331837B1Gripper with self-compensating jaw guides
Publication Date: 2013.03.13 PHD INC
  • EP2331837B1 patent drawingFigure 1
  • EP2331837B1 patent drawingFigure 2
  • EP2331837B1 patent drawingFigure 3

AI summary

The present disclosure describes a gripper assembly which in one form includes a body, at least one jaw, a longitudinally extending wedge, and a spring. The body has a slot disposed therein and opposed longitudinally extending walls. The jaw is laterally slideable within the slot. The longitudinally extending wedge is fitted along the longitudinally extending wall. The jaw comprises a surface that is engageable with the wedge. The surface of the jaw is slideable along the wedge. And a spring biases the wedge toward the jaw to reduce the running clearance between the two structures.