Resilient Blocking Element Prevents Vibration Detachment in Tool Attachments

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Solution Overview

Problem

Existing tool attachments for handheld power tools can automatically detach due to vibrations during operation, potentially causing damage and injury.

Innovation Solution

A tool attachment with a locking unit featuring a rotatable locking body and a resilient blocking element that interacts with the fastening interface, preventing automatic release by engaging in locking teeth and using elastic deformation for secure locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bayonet connection is used for locking the tool attachment, then the locking mechanism is simple and easy to operate, but the connection can become detached automatically due to vibrations during operation

Engineering Contradiction:
Improvelocking mechanism operationVSAvoidconnection stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The blocking element is designed to preemptively counteract the detaching force generated by vibrations before the bayonet connection can become loose. By positioning the blocking element to engage with the locking body in the locked state, it creates a preliminary counter-force that prevents the vibration-induced detachment from occurring in the first place

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The blocking element is pre-positioned and spring-loaded to be ready for immediate engagement. When the locking body rotates into the locked position, the blocking element is already in place to provide immediate stabilization, preventing any subsequent loosening due to vibrations during operation

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a blocking element with elastic deformation is used to prevent automatic release, then the locking reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blocking element utilizes its own elastic deformation properties to automatically engage and disengage based on the rotational position of the locking body. The spring force causes the blocking element to flex and lock into position without requiring external actuation, and it automatically releases when the locking body rotates to the unlocked position, making the system self-regulating

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The blocking element changes its physical state through elastic deformation - flexing under spring force to engage with the locking body in the locked state, and releasing when the locking body rotates. This parameter change (from flexed to relaxed state) provides the locking and unlocking functionality without additional mechanical components

Inventive Principle:
Principle #35Parameter changes

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 a safe, reliable, and cost-effective locking mechanism that prevents automatic detachment during operation, ensuring stable and secure attachment to the handheld power tool.

Implementation Method 1

the blocking member is designed to be resilient at least in some areas and has at least one blocking section which, in the locked state, is acted upon by elastic deformation of the blocking member against the fastening interface of the hand-held power tool

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2745992B1Tool attachment for a manual tool machine
Publication Date: 2020.08.05 ROBERT BOSCH GMBH
  • EP2745992B1 patent drawingFigure 1
  • EP2745992B1 patent drawingFigure 2
  • EP2745992B1 patent drawingFigure 3~4

AI summary

The attachment (200) has a locking unit (202) for attaching the attachment to a fastening interface of a handheld machine tool in an unlocking condition. The locking unit locks the attachment to the interface in a locking condition. The locking unit has a rotatable locking body (300) and a locking element (400) that is designed for inhibiting rotation of the locking body from rotating position to another rotating position during the locking condition. The element is flexibly designed, and has a locking section. The element is formed as a single-piece with a blocking unit (500). An independent claim is also included for a handheld machine tool.