Keyless Chuck Sleeve Biasing to Prevent Inertial Locking

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Solution Overview

Problem

Keyless chucks on power drivers can 'lock' or fail to open by hand, especially during drilling operations, due to inertial forces causing incremental tightening or loosening of the jaws, leading to operational issues.

Innovation Solution

A biasing element is introduced between the sleeve and nut to bias the sleeve toward a neutral position, limiting or preventing the transfer of inertial forces, and a gap is provided to allow movement before engagement, which can be filled by a spring or flexible cushion to absorb these forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a keyless chuck is used on a power driver, then the chuck can be tightened or loosened by hand or actuation of the driver motor, but inertial forces during operation cause incremental tightening or loosening of the jaws leading to the chuck locking or failing to open

Engineering Contradiction:
Improvemanual adjustment of chuckVSAvoidchuck opening reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The biasing element applies a preliminary counteracting force to the inertial forces generated during driver operation. By positioning the biasing element between the sleeve and nut, it creates an opposing force that prevents the inertial forces from causing incremental tightening or loosening of the jaws, thereby preventing the chuck from locking or failing to open.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The biasing element acts as a cushioning mechanism that absorbs the inertial forces before they can cause harmful effects. The element is pre-positioned in the gap between the sleeve and nut, ready to absorb shock and limit the transfer of inertial forces to the nut and jaws, preventing operational issues before they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Power

If the sleeve is directly engaged with the nut, then rotational force is efficiently transferred, but inertial forces cause unwanted movement and tightening/loosening of the jaws

Engineering Contradiction:
Improverotational force transferVSAvoidinertial force transfer
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The biasing element serves as an intermediary component positioned between the sleeve and nut. It mediates the interaction between these two components by allowing rotational force to be transferred while simultaneously limiting the transfer of inertial forces. The element acts as a buffer that distinguishes between useful rotational motion and harmful inertial shocks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The biasing element is pre-positioned in the gap between the sleeve and nut to cushion against inertial forces before they can cause harmful effects. This beforehand cushioning allows efficient power transmission during normal operation while protecting the system from the harmful effects of sudden inertial forces during clutch engagement or disengagement.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 prevents the 'locking' or loosening of the chuck, ensuring smooth operation and easy manual adjustment of the chuck, enhancing usability and reliability in various applications.

Implementation Method 1

A gap is provided between a driving edge of a drive dog and an engagement edge of a nut groove. The gap may be filled with a spring or other flexible cushion that biases the sleeve toward a neutral position and that limits or prevents the transfer of inertial forces

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The gap may be filled with a spring or other flexible cushion that biases the sleeve toward a neutral position and that limits or prevents the transfer of inertial forces

Methodology Applied
Scientific EffectFlexibility: Elasticity

Data Source

PatentEP3525968B1Chuck with slip protection
Publication Date: 2021.08.11 JACOBS CHUCK MANUFACTURING (SUZHOU) CO LTD
  • EP3525968B1 patent drawingFigure 1
  • EP3525968B1 patent drawingFigure 2
  • EP3525968B1 patent drawingFigure 3

AI summary

A chuck is provided for use with a powered driver having a rotatable drive shaft. The chuck includes a plurality of jaws (22) movably disposed in passageways (40) of a cylindrical body (14), a nu t(16) rotatably mounted about the body (14) and in communication with the jaws (22) such that rotation of the nut (16) in a closing direction moves the jaws (22) toward each other and rotation of the nut (16) in an opening direction moves the jaws (22) away from each other, and a sleeve rotatably mounted about the body (14). The sleeve is in communication with the nut (16) such that rotation of the sleeve rotationally drives the nut (16). The chuck also including a biasing element (208) disposed between the nut (16) an at least a portion of the sleeve configured to bias the sleeve toward a neutral position. The biasing element (208) limits an inertial force of the sleeve applied to the nut during operation of the powered driver.