Keyless Collet Chuck With Detent Click for Bit Clamping Feedback

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Solution Overview

Problem

Rotary power tools lack effective mechanisms for providing tactile feedback when securing tool bits, making it difficult for operators to confirm proper engagement and clamping force.

Innovation Solution

A chuck design featuring a detent member that transmits torque to an inner sleeve, allowing for tactile feedback through axial displacement when the collet is tightened or loosened, utilizing toothed portions and a biasing spring to create a clicking sensation for user confirmation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional collet or chuck is used to secure tool bits, then the tool bit can be held securely for co-rotation, but there is no tactile feedback mechanism to confirm proper engagement and clamping force

Engineering Contradiction:
Improvetool bit securityVSAvoidoperator confirmation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism through a detent member that provides tactile feedback to the operator. When the collet is properly tightened, the detent member engages with the inner sleeve, creating a noticeable click or stop sensation that confirms correct engagement and clamping force to the operator.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The detent member acts as an intermediary between the collet tightening mechanism and the operator. It translates the mechanical state of the tightened collet into tactile feedback, allowing the operator to confirm proper engagement without directly measuring clamping force.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the detent member is made axially displaceable relative to the inner sleeve, then tactile feedback is created through rotation, but the structure becomes more complex

Engineering Contradiction:
Improvetactile feedbackVSAvoidchuck structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The detent member is nested within the inner sleeve structure, with the detent member positioned inside the central aperture area. This nesting arrangement allows the displaceable detent member to provide tactile feedback while remaining integrated within the existing chuck components, minimizing overall structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Power

If the outer sleeve is rotationally fixed to the detent member, then torque transmission is improved for tightening, but the detent member must withstand higher mechanical stresses

Engineering Contradiction:
Improvetorque transmissionVSAvoiddetent member durability
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The detent member is pre-configured with its axial displacement capability and engagement features before the tightening operation begins. This preliminary preparation allows the detent member to smoothly transition between engaged and disengaged states, distributing mechanical stresses more evenly and preventing sudden load shocks that could compromise durability.

Inventive Principle:
Principle #10Preliminary action

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 chuck design ensures secure tool bit engagement with tactile feedback, allowing operators to confirm proper clamping force, enhancing user experience and tool bit security.

Implementation Method 1

The detent member is configured to transmit torque to the inner sleeve to tighten or untighten the collet. The detent member is axially displaceable relative to the inner sleeve in response to rotation between the detent member and the inner sleeve to create tactile feedback.

Methodology Applied
Scientific EffectTorque transmission: Torque

Implementation Method 2

utilizing toothed portions and a biasing spring to create a clicking sensation for user confirmation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4212270A1collet
Publication Date: 2023.07.19 TECHTRONIC CORDLESS GP
  • EP4212270A1 patent drawingFigure 1
  • EP4212270A1 patent drawingFigure 2~3
  • EP4212270A1 patent drawingFigure 4

AI summary

Keyless chuck (14) for portable power tools that produces an audible click or a tactile feedback when a bit is clamped. The chuck (14) includes a base (18) and an inner sleeve (30) threadedly coupled to the base (18). The inner sleeve (30) has a central aperture (20). A collet (26) is disposed within the central aperture (20) and configured to be engaged by a conical portion (30c) of the inner sleeve (30) to be tightened or untightened. An outer sleeve (42b) with a knurled surface (124) surrounds the inner sleeve (30). An axially mobile detent member (ring 34) disposed between the sleeves rotates with the outer sleeve (42b) and is biased axially against a track on the inner sleeve (30) so as to normally transmit rotation to the inner sleeve and so as to slip by a few degrees when the collet is sufficiently tightened, producing a click.