Power Tool Front Attachment Indexing With Safe Axial Unlocking

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Solution Overview

Problem

Existing power tools with indexable elongated bodies face risks of accidental rotation during indexing, leading to potential user injuries due to the elongated body spinning like a propeller or forcefully moving, and there is a need for a secure, compact, and efficient detachment mechanism.

Innovation Solution

A power tool arrangement featuring a base structure and a drive shaft that allows rotational locking, enabling secure indexing and detachment of a front part attachment through a multi-position mechanism, including a locked, intermediate, and unlocked position, ensuring the drive interface is disengaged before the indexing interface, thereby preventing accidental spinning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the elongated body is made rotatable for indexing to improve access to narrow spaces, then adaptability is improved, but the risk of accidental rotation and user injury increases

Engineering Contradiction:

Improveindexing capabilityVSAvoidaccidental rotation risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by requiring the output element to be moved to an intermediate position where the driven part disengages from the drive part before the indexing part disengages from the base part. This sequence ensures that the drive connection is broken before the indexing connection, preventing accidental rotation during indexing operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the locking mechanism into two distinct parts: an indexing part for angular positioning and a driven part for drive transmission. This segmentation allows independent control of indexing and driving functions, enabling the driven part to disengage before the indexing part during the unlocking sequence, thereby preventing accidental rotation.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a multi-position mechanism is implemented to prevent accidental rotation, then safety is improved, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the indexing mechanism and drive mechanism into a single integrated output element that performs both functions. The indexing part and driven part are combined in one component that moves axially to control both disengagement sequences, simplifying the overall structure while maintaining safety through the intermediate position requirement.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a nested arrangement where the driven part is positioned within or alongside the indexing part of the output element. This nesting allows both parts to share the same axial movement path and control mechanism, reducing the number of independent components needed while ensuring the driven part disengages before the indexing part.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If the driven part disengages before the indexing part during unlocking, then accidental rotation is prevented, but the detachment process requires more steps

Engineering Contradiction:

Improveaccidental rotation preventionVSAvoiddetachment simplicity

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies self-service by designing the output element to automatically follow a predetermined extraction path when removed from the base structure. The axial movement of the output element naturally causes the driven part to disengage from the drive part before the indexing part disengages from the base part, eliminating the need for manual control of the disengagement sequence and simplifying user operation.

Inventive Principle:

Principle #25Self-service

4Volume of moving object

If a compact design is pursued, then device size is reduced, but the mechanism for secure indexing and detachment becomes more challenging to implement

Engineering Contradiction:

Improvedevice sizeVSAvoidlocking mechanism complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent uses axial movement (one-dimensional linear motion) to control the disengagement sequence of both the driven part and indexing part. By translating the output element along the rotation axis, the patent achieves complex sequential disengagement in a simple linear path, maintaining compact dimensions while ensuring safety through the intermediate position requirement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4392206B1Arrangement for power tool, front part attachment and power tool

Publication Date: 2025.10.08 ATLAS COPCO IND TECHNIQUE AB INTELLECTUAL PROPERTY DEPARTMENT

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AI summary

An arrangement (16) for a power tool (10) comprising a drive part (40) for rotational locking to a drive shaft (22) with respect to a rotation axis (24 ); a base part (32) for fixation to a base structure (20); and an output element (48) having an indexing part (42) and a driven part (46) rotatable relative to the indexing part about the rotation axis; wherein the output element is movable along the rotation axis relative to the drive part and the base part from a locked position (84) where the indexing part engages the base part and the driven part engages the drive part, to an intermediate position (98) where indexing part engages the base part and the driven part is disengaged from the drive part, and further to an unlocked position (100) where the indexing part is disengaged from the base part and the driven part is disengaged from the drive part.