Power Tool Clamp Lever Pivoting Direction for Hand Safety

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Solution Overview

Problem

Existing power tools with lever-operated clamping mechanisms pose a risk of hand injury due to accidental contact with sharp tool edges during the release process, as the lever must be pivoted towards the tool, increasing the likelihood of hand slips and contact.

Innovation Solution

A power tool design featuring a pivotable grasping part that moves away from the tool during the release process, utilizing a spring-based clamp mechanism to ensure the hand remains safe from the tool's edge, with a distinct pivoting direction for clamping and releasing modes to differentiate between operation and storage positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the lever is pivoted toward the tool to operate the clamping mechanism, then the clamping function is achieved, but the operator's hand may accidentally contact the sharp tool edge causing injury

Engineering Contradiction:
Improvelever operationVSAvoidhand injury risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional lever pivoting direction. Instead of pivoting the lever toward the tool (as in prior art), the lever is designed to pivot away from the tool. This inversion maintains the clamping functionality while ensuring the operator's hand moves in the opposite direction, away from the sharp tool edge, thereby eliminating the injury risk associated with hand slips during lever operation

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If the grasping part is positioned close to the tool for compact design, then the device size is reduced, but the operator's hand is at risk of contact with the sharp tool

Engineering Contradiction:
Improvecompact designVSAvoidhand injury risk
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent resolves the spatial conflict by utilizing a different dimensional approach. The lever is configured to extend and pivot in a direction perpendicular to the tool axis, creating spatial separation between the operator's hand and the sharp tool edge during operation. This dimensional reconfiguration allows the grasping part to be positioned compactly while maintaining safety distance during lever pivoting

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

3Reliability

If a spring-based clamp mechanism is used to secure the tool, then the clamping force is automatically maintained, but a larger force is required to pivot the lever against the spring force

Engineering Contradiction:
Improvetool securingVSAvoidlever actuation force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent employs a spring element that acts as a counterbalancing force to maintain reliable tool securing. The spring is positioned and configured to exert a continuous clamping force on the tool, ensuring secure retention during operation. The lever mechanism is designed to overcome this spring force during tool attachment and detachment, providing automatic tool securing while requiring controlled manual force for operation

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 design enhances safety by keeping the operator's hand away from the tool during release, requiring a larger force to pivot the grasping part against the spring force, reducing the risk of injury and allowing secure storage of the grasping part to prevent vibration-induced movement.

Implementation Method 1

The tool is held (sandwiched) between the working spindle and the fastening element by a clamping force generated by a spring element provided inside the working spindle

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the clamp mechanism optionally comprises an urging member (e.g., a spring and/or an elastic material) and is adapted such that the tool is interposingly held (clamped) by an urging (biasing or spring) force of the urging member

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2752278B1Power tool having improved tool accessory securing mechanism
Publication Date: 2019.11.20 MAKITA CORP
  • EP2752278B1 patent drawingFigure 1
  • EP2752278B1 patent drawingFigure 2
  • EP2752278B1 patent drawingFigure 3

AI summary

A power tool (100) comprises a clamp shaft holding mechanism (130) for detachably holding a tool (200) and an operating mechanism (104) for operating the clamp shaft holding mechanism (130). The operating mechanism (104) comprises a grasping part (151; 251; 351) adapted to be manipulated by a user to switch between a clamped state and an unclamped state with respect to the tool (200) by moving the grasping part (151; 251; 351) in a direction away from the tool (200), thereby ensuring safer tool removal and attachment operations.