Power Tool Clamping Shaft Release for Safe Accessory Changes

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Solution Overview

Problem

Existing power tools require complex procedures and risk unintentional actuation when replacing tool accessories due to the lack of a simple and secure clamping mechanism that prevents accidental re-clamping during accessory changes.

Innovation Solution

A power tool design featuring a clamping shaft with a biasing member and a release member, where the actuating member disengages the release member from the spindle upon upward pressure, allowing for simple single-action clamping and reduced risk of unintentional actuation, utilizing a force-amplifying mechanism to secure the tool accessory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple clamping mechanism is used for tool accessory attachment, then ease of operation is improved, but reliability deteriorates due to risk of unintentional actuation

Engineering Contradiction:

Improveease of accessory attachmentVSAvoidrisk of unintentional actuation

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The release member is preliminarily engaged with the spindle in a locked position before the clamping operation begins. This preliminary engagement ensures that the biasing force is initially released, preventing unintentional actuation during accessory attachment while maintaining simple single-action clamping operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The actuating member serves as an intermediary between the user's pressing action and the release member. It translates the upward pressing force applied during accessory attachment into the disengagement of the release member from the spindle, enabling controlled restoration of biasing force transmission without direct contact between the user and the release mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a complex clamping mechanism with multiple steps is used, then reliability is improved by preventing accidental actuation, but ease of operation deteriorates

Engineering Contradiction:

Improveprevention of accidental re-clampingVSAvoidcomplexity of accessory replacement procedure

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The clamping mechanism is segmented into distinct functional components: the release member for controlling biasing force transmission, the actuating member for user interaction, and the clamping shaft for actual clamping. This segmentation allows each component to perform its specific function simply, achieving reliable prevention of accidental actuation through the coordinated action of these separate elements rather than through a complex multi-step procedure.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the biasing force is continuously transmitted to the clamping shaft, then clamping reliability is improved, but ease of operation deteriorates due to inability to quickly release for accessory replacement

Engineering Contradiction:

Improveclamping force maintenanceVSAvoidspeed of accessory replacement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The transmission state of the biasing force is dynamically changed based on operational needs. The release member can selectively switch between a locked position (releasing biasing force for quick accessory replacement) and an unlocked position (transmitting biasing force for secure clamping). This dynamic adaptability allows the system to maintain clamping reliability when needed while enabling rapid accessory replacement when required.

Inventive Principle:

Principle #15Dynamics

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

Facilitates easy and secure attachment and detachment of tool accessories with reduced risk of accidental re-clamping, enhancing user convenience and safety by allowing single-handed operation and minimizing the risk of unintentional actuation.

Implementation Method 1

The biasing member generates a biasing force that is transmitted to the clamping shaft to bias the clamping shaft upward

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

The actuating member is configured to be moved upward in response to being pressed upward by the clamping part or by the tool accessory and thereby disengage (unlock) the release member from the spindle

Methodology Applied

Scientific EffectForce transmission: Mechanical Force

Data Source

PatentUS11364545B2Power tool

Publication Date: 2022.06.21 MAKITA CORP

AI summary

A power tool includes a housing (10), a spindle (4) supported in the housing to be pivotable or rotatable about a driving axis, a clamping shaft (60) that is selectively movable in the up-down direction relative to the spindle, a biasing member (70), a release member (71) and an actuating member (50). The release member is selectively movable in the up-down direction relative to the spindle and is configured to selectively interrupt transmission of upward biasing force from the biasing member to the clamping shaft. The release member is also configured to be locked to the spindle in a locked position while transmission of the biasing force is being interrupted. The actuating member is movable upward in the up-down direction relative to the spindle in response to being pressed upward by a clamping part (64) or by a tool accessory (91) to thereby unlock the release member from the spindle.