Chuck Plunger Self-Positioning to Eliminate Grip Backlash

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Solution Overview

Problem

Existing chuck devices experience misalignment of the workpiece due to backlash and elastic deformation, leading to reduced gripping accuracy and potential vibration during processing.

Innovation Solution

The chuck device incorporates a plunger with protruding portions and a chuck body with fitting recesses, allowing for elastic deformation-guided positioning to align the plunger with predetermined positions, reducing misalignment and increasing rigidity to prevent deformation and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a slight gap is formed between the chuck body and the plunger to allow sliding movement, then the plunger can move along the rotational axis, but backlash occurs around the rotational axis causing misalignment of the workpiece grip position

Engineering Contradiction:
Improvesliding movement of plungerVSAvoidgrip position accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

A positioning portion is introduced as an intermediary element between the plunger and chuck body. The positioning portion includes a positioning surface on the plunger that contacts a corresponding positioning surface on the chuck body, serving as a mediator to eliminate backlash while preserving the necessary sliding movement capability for grip release.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The positioning portion is designed to preemptively counteract the backlash effect before it causes misalignment. By providing pre-positioning contact surfaces, the system prevents the plunger from deviating within the backlash range, ensuring accurate grip position from the outset.

Inventive Principle:
Principle #9Preliminary anti-action

2Strength

If the outer circumferential portion of the plunger is elastically deformed by the reaction force during work gripping, then the plunger is pressed against the chuck body, but the plunger becomes fixed and cannot move, causing grip position misalignment

Engineering Contradiction:
Improvegrip force transmissionVSAvoidplunger movability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The plunger structure is segmented into distinct functional zones: an outer circumferential portion that elastically deforms to transmit grip force, and a positioning portion that maintains controlled movement capability. This segmentation allows different parts of the plunger to perform different functions simultaneously without interfering with each other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the plunger are given different mechanical properties. The outer circumferential portion is designed with elastic characteristics to absorb and transmit grip forces, while the positioning portion maintains sufficient rigidity and movability to preserve positioning accuracy and enable grip release through sliding movement.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the slide hole is located at a position misaligned with the predetermined position with respect to the guide groove, then the plunger can accommodate backlash, but the grip position misaligns with the reference position

Engineering Contradiction:
Improvebacklash accommodationVSAvoidreference position alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The positioning portion acts as an intermediary that decouples the relationship between the slide hole position and the guide groove position. By introducing this intermediate positioning mechanism, the system can accommodate backlash through the positioning portion's movement while ensuring the grip position aligns with the reference position through the guide groove's precise positioning.

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 configuration ensures precise gripping and reduces the likelihood of workpiece misalignment and vibration, enhancing the overall accuracy and stability of the chuck device.

Implementation Method 1

an outward elastic deformation that occurs, through gripping of the work with the top jaws, at portions of the plunger which correspond to the engaging means causes the portions deformed by the elastic deformation to slide on the positioning portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3450067B1Chuck device
Publication Date: 2023.08.09 KITAGAWA IRON WORKS CO LTD
  • EP3450067B1 patent drawingFigure 1
  • EP3450067B1 patent drawingFigure 2
  • EP3450067B1 patent drawingFigure 3

AI summary

An inner circumferential surface of a chuck body (2) has three fitting recesses (22) curved as viewed from a rotational axis (C1). An outward elastic deformation that occurs, through gripping of a work (W1) with top jaws (5), at portions of a plunger (3) which correspond to slide holes (31a) causes the portions deformed by the elastic deformation to slide on the respective recessed portions (22) so that the plunger (3) is moved to cause a symmetry axis (Y1) of the slide hole (31a) to coincide with a symmetry axis (Y2) of a guide groove (25) of the chuck body (2).