Power Tool Accessory Coupling With Dual Axial and Rotational Locking

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Solution Overview

Problem

Existing rotary power tools lack an efficient and user-friendly mechanism for securely attaching and detaching various accessories, which can lead to axial and rotational misalignment, affecting tool performance and user convenience.

Innovation Solution

A dual-sleeve attachment mechanism with a ball detent system that axially locks and rotationally secures accessories to the power tool, utilizing a cam surface and spring-loaded sleeves to engage and disengage the ball detents, ensuring secure attachment and easy release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple attachment mechanism is used, then device complexity is reduced, but axial and rotational locking reliability deteriorates

Engineering Contradiction:
Improveattachment mechanism complexityVSAvoidaxial and rotational locking reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The attachment mechanism is divided into two independent but coordinated locking systems: axial locking (via ball detents engaging with the spindle) and rotational locking (via mating members with engagement elements). This segmentation allows each subsystem to specialize in one locking function, achieving reliable dual-directional security without requiring an overly complex integrated mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner sleeve containing ball detents is nested within the outer sleeve containing mating members. This nested structure allows both locking functions to be integrated in a compact arrangement where the inner axial locking mechanism is contained within the outer rotational locking mechanism, reducing overall complexity while maintaining dual locking capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a secure locking mechanism is implemented, then attachment reliability is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveattachment securityVSAvoidattachment and detachment ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The axial and rotational locking functions are merged into a single coordinated mechanism actuated by one outer sleeve. When the outer sleeve moves axially, it simultaneously controls both the ball detents (inner sleeve) and the mating members (outer sleeve), allowing secure dual-directional locking through a single operational motion rather than requiring separate controls for each locking function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mechanism transitions between locked and unlocked states through dynamic movement of the sleeves. The spring-loaded inner sleeve dynamically adjusts the ball detents, while the outer sleeve dynamically positions both locking systems. This dynamic behavior allows the mechanism to securely lock during operation and easily unlock when actuated, balancing reliability with operational ease.

Inventive Principle:
Principle #15Dynamics

3Reliability

If axial and rotational locking are both implemented, then attachment security is improved, but device complexity increases

Engineering Contradiction:
Improvedual-directional locking securityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The outer sleeve serves multiple functions: it acts as the operational interface for the user, controls the axial position of the inner sleeve, and directly engages with the mating members for rotational locking. This multi-functionality reduces the need for separate components for each function, achieving dual-directional locking without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The mechanism uses axial movement (one dimension) of the outer sleeve to control both axial and rotational locking functions. By converting a single linear motion into dual locking actions through the coordinated movement of nested sleeves and engagement elements, the mechanism achieves complex dual-directional security without requiring complex multi-dimensional actuation.

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

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 mechanism provides reliable axial and rotational locking of accessories, enhancing tool performance and user convenience by allowing easy attachment and detachment while maintaining secure engagement.

Implementation Method 1

an inner sleeve biased towards a first direction to axially lock the accessory to the power tool

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

an outer sleeve biased towards a second direction opposite the first direction to rotationally lock the accessory to the power tool

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

utilizing a cam surface and spring-loaded sleeves to engage and disengage the ball detents

Methodology Applied
Scientific EffectCam: Cam

Data Source

PatentEP3768469B1Attachment mechanism for a power tool
Publication Date: 2024.01.17 MILWAUKEE ELECTRIC TOOL CORP
  • EP3768469B1 patent drawingFigure 1
  • EP3768469B1 patent drawingFigure 2
  • EP3768469B1 patent drawingFigure 3

AI summary

An accessory for use with a rotary power tool having a rotatable spindle and a first mating member. The accessory includes a housing having a body and a plurality of arms extending therefrom, a hub rotatably supported within the housing between the arms and configured to be coupled to the spindle to receive torque therefrom, a ball detent disposed within the hub and selectively engagable with the spindle to axially lock the accessory to the power tool, a sleeve axially slidable along the arms and relative to the hub between a first position in which the sleeve biases the ball detent radially inward and into engagement with the spindle when coupled to the hub to axially secure the accessory to the tool, and a second position in which the ball detent is disengageable from the spindle to release the accessory from the tool, and a second mating member axially fixed to the arms of the housing, wherein the sleeve is slidable between the second mating member and the body of the housing, and wherein the first and second mating members are engaged when the accessory is axially secured to the tool to rotationally fix the accessory to the tool.