Hand Tool Attachment With Segmented Locking And Coupling

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Solution Overview

Problem

Existing handheld power tool accessories are limited in functionality and usability due to restrictive attachment mechanisms, which hinder their application in various tasks.

Innovation Solution

A modular attachment system for handheld power tools featuring a torque-transmitting coupling unit, a locking mechanism for secure attachment, and an accessory interface unit that allows for detachable and adjustable connections, enabling versatile operation and easy cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a restrictive attachment mechanism is used to connect the accessory device to the hand-held power tool, then the connection stability is improved, but the functionality and applicability of the accessory device are limited

Engineering Contradiction:
Improveconnection stabilityVSAvoidfunctionality and applicability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The attachment device is divided into separate functional modules: a coupling unit with drive shaft for torque transmission, a locking unit with locking elements for secure connection, and a mixing unit with mixing elements. This modular segmentation allows the attachment to maintain stable connection through the locking unit while enabling functionality extension by replacing or adjusting mixing units with different mixing elements for various applications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling unit and locking unit are designed as universal components that can interface with standard hand-held power tool output shafts and provide reliable torque transmission. The mixing unit can be adapted with different mixing elements (stirring, whipping, beating, kneading, chopping, slicing) to perform multiple functions, making the attachment versatile across different culinary applications while maintaining the same stable connection mechanism.

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

2Reliability

If a fixed attachment mechanism is used, then the torque transmission reliability is improved, but the ease of maintenance and cleaning is worsened

Engineering Contradiction:
Improvetorque transmission reliabilityVSAvoidease of maintenance and cleaning
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The attachment is segmented into a permanent coupling unit with locking unit that remains attached to the power tool, and a removable mixing unit that can be detached for cleaning. The coupling unit maintains torque transmission reliability through its locking elements, while the mixing unit with mixing elements can be easily removed and cleaned separately, solving the maintenance accessibility problem.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking unit provides dynamic locking during operation to ensure reliable torque transmission, but allows easy release when needed for maintenance. The mixing unit can be quickly detached from the coupling unit by releasing the connection, enabling easy access to the mixing elements for cleaning without compromising the secure connection during actual use.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If a simple connection mechanism is used, then the ease of operation is improved, but the concentricity and wear reduction are worsened

Engineering Contradiction:
Improveease of attachmentVSAvoidconcentricity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The coupling geometry between the drive shaft and output shaft uses asymmetric shapes (such as hexagonal or keyed connections) that provide easy alignment and attachment while ensuring precise concentricity. The asymmetric design guides the mixing unit into correct rotational alignment during attachment, preventing eccentric operation and reducing wear on moving parts, while still being simple to operate.

Inventive Principle:
Principle #4Asymmetry

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 enhances the functionality of handheld power tools by ensuring reliable torque transmission, secure attachment, and easy maintenance, expanding their application range to tasks like frothing milk and other kitchen functions with improved concentricity and reduced wear.

Implementation Method 1

a coupling unit for transmitting torque from the hand-held power tool to the mixing unit

Methodology Applied
Scientific EffectTorque transmission: Torque

Implementation Method 2

The locking unit allows the attachment to be reliably and releasably locked to the housing of the hand-held power tool. The locking mechanism can be force-fit and/or form-fit.

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Data Source

PatentEP3144108B1Attachment for a hand tool
Publication Date: 2022.03.02 ROBERT BOSCH GMBH
  • EP3144108B1 patent drawingFigure 1a~1b
  • EP3144108B1 patent drawingFigure 1c
  • EP3144108B1 patent drawingFigure 2a~2b

AI summary

Attachment (200) for a hand-held power tool (100) comprising a stirring unit (230) with stirring element (234) and stirring shaft (232), a coupling unit (220) for transmitting torque from the hand-held power tool (100) to the stirring unit (230) with a drive shaft (226) which can be coupled to an output shaft (120) of the hand-held power tool (100) in a rotationally fixed manner, and a locking unit (210) for locking an attachment (200) to a housing (110) of a hand-held power tool (100), thereby ensuring reliable operation, in particular of milk frothing, of the attachment (200).