Rotary Quick-Change Tool Head Locking for Low-Force Detachment

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Solution Overview

Problem

Existing power tools require high finger strength for tool holder detachment due to small, line contact areas with weak fixation stability and tool holder vibration, making them inconvenient for users, especially women.

Innovation Solution

A head and body rapid replacing structure using a torsion ring with rotating head locking pieces that move in a straight line for easy locking and unlocking, employing a rotary mechanism instead of pressing, with surface contact for enhanced stability and reduced vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an elastic clamp is used to fix the tool holder, then the tool holder can be detached, but the finger strength required for detachment is too high and operation is inconvenient

Engineering Contradiction:
Improveease of tool holder detachmentVSAvoidfinger strength required
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent inverts the conventional elastic clamp mechanism by using a rigid locking piece that moves linearly instead of an elastic element that expands. The locking piece is driven by a cam surface on the torsion ring during rotation, converting rotational motion into linear locking/unlocking motion. This inversion eliminates the need for high finger strength while maintaining secure fixation.

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

Solution Approach 2:

The patent replaces the elastic mechanical system with a rigid mechanical system driven by cam surfaces and torsion ring rotation. Instead of relying on elastic deformation and expansion forces, the system uses controlled linear movement of the locking piece guided by cam profiles, substituting the elastic clamp mechanism with a more operationally convenient rigid linkage system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If an elastic clamp with small line contact area is used, then the structure is simple, but the fixation stability is weak and tool holder vibration occurs

Engineering Contradiction:
Improvefixation stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from line contact (one-dimensional contact) to surface contact (two-dimensional contact) by designing the locking piece with a blocking surface that contacts the tool holder's clamping platform over an area rather than along a line. This dimensional change significantly increases contact area, improving fixation stability and reducing vibration while maintaining structural simplicity through the rigid locking mechanism.

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

3Ease of operation

If a pressing mechanism is used for unlocking, then the structure is compact, but the operation is inconvenient and requires high finger strength

Engineering Contradiction:
Improveease of unlocking operationVSAvoidunlocking mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces dynamic elements by using a torsion ring that rotates during the unlocking process. The rotation of the torsion ring drives the locking piece through cam surfaces to move linearly from the locked to unlocked position. This dynamic rotational-to-linear motion conversion provides mechanical advantage, reducing the force required for unlocking while adding controlled complexity to the mechanism.

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

The solution provides easy operation with reduced force requirement, improved locking stability, and minimized tool holder vibration, enhancing user convenience and reliability.

Implementation Method 1

A torsion ring which is rotationally arranged in the body shell... An energy storage device resetting after driving the torsion ring to rotate

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

An energy storage device resetting after driving the torsion ring to rotate

Methodology Applied
Scientific EffectEnergy storage: Mechanical Accumulator

Data Source

PatentEP4166279B1Quick-change structure for head and body of multifunctional power tool and multifunctional power tool
Publication Date: 2025.08.27 ZHEJIANG DESHI ELECTRICAL APPLIANCE CO LTD
  • EP4166279B1 patent drawingFigure 1
  • EP4166279B1 patent drawingFigure 2
  • EP4166279B1 patent drawingFigure 3

AI summary

The present invention discloses a head and body rapid replacing structure of a multi-functional power tool and a multi-functional power tool. The rapid replacing structure comprises a body shell; a torsion ring which is rotationally arranged beside a socket in the body shell and of which the axis is at least parallel to that of the socket; a head detachably inserted in a jack of the torsion ring; an energy storage device resetting after driving the torsion ring to rotate; and head locking pieces that can move in a straight line between a first position and a second position along the direction perpendicular to the axis of the torsion ring during the rotation of the torsion ring. In the first position, each head locking piece has a blocking part which extends into the jack of the torsion ring and is located on the movement path of a clamping platform at the side wall of the head; and in the second position, each head locking piece does not have a part located on the movement path of the clamping platform. The solution adopts a rotary unlocking structure instead of a pressing structure, so the force to be applied by hands to unlock is smaller, and the operation is easy; and face contact locking is adopted, so the stability is good, and the vibration during work can be reduced.