Rotating Handle Latching Mechanism for Hand Tool Housing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electric hand tools face challenges with screw connections used for rotating operating elements, which are cumbersome to produce, prone to loosening, and require additional parts, increasing complexity and space requirements.

Innovation Solution

A latching connection between the operating and functional elements, utilizing a snap-in mechanism with an O-ring seal and complementary latching means, allowing for tool-free assembly and disassembly without additional parts, and reducing friction and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a screw connection is used to connect the operating element and the functional element, then the connection is secure, but the number of parts increases and the manufacturing complexity increases

Engineering Contradiction:
Improveconnection securityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the connection function directly into the operating element and functional element by forming projection and receptacle features during injection molding. This merging of the connection mechanism into the main components eliminates the need for separate screws and fasteners, reducing part count while maintaining secure connection through the latching mechanism.

Inventive Principle:
Principle #5Merging (Combining)

2Volume of stationary object

If a small screw is selected to minimize installation space, then the space requirement is reduced, but the difficulty of producing the screw connection increases and additional tools are required

Engineering Contradiction:
Improveinstallation spaceVSAvoidproduction difficulty
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The latching connection is designed to be self-assembling without requiring external tools or specialized manufacturing processes. The projection automatically engages with the receptacle when the operating element is inserted, eliminating the need for screwdrivers, torque tools, or other specialized equipment. The connection is created through simple insertion and latching actions.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If a screw connection is used without special countermeasures, then the assembly is simple, but the connection can loosen under certain circumstances when turning the control element

Engineering Contradiction:
Improveassembly simplicityVSAvoidconnection stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The latching connection incorporates dynamic elements including spring-loaded latching balls that automatically engage with corresponding recesses in the functional element. This dynamic mechanism maintains constant connection pressure and prevents loosening during rotation, while the anti-rotation means provide form-fitting engagement to prevent any relative movement between components.

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If a latching connection is used, then the assembly is easy and quick without tools, but additional sealing requirements are introduced

Engineering Contradiction:
Improveassembly easeVSAvoidsealing requirements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent employs an O-ring seal, which is a flexible elastomeric element that provides sealing through its ability to deform and conform to the mating surfaces. The O-ring is installed in a groove around the opening where the functional element passes through the housing, creating a seal that prevents contamination while accommodating the latching connection's movement and maintaining simplicity.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2101957B1Electric device with locked-on rotatable operating element
Publication Date: 2013.04.24 ROBERT BOSCH GMBH
  • EP2101957B1 patent drawingFigure 1~2
  • EP2101957B1 patent drawingFigure 3~4
  • EP2101957B1 patent drawingFigure 5

AI summary

The invention relates to an electric device, and in particular to an electric hand-held machine tool (2), comprising a housing (4), a rotatable operating element (8) arranged outside the housing (4) and a functional element (12), arranged inside the housing (4) and connected to the operating element (8) in a rotationally fixed manner. It is provided that the operating element (8) and the functional element (12) are locked together through an opening (14) in the housing (4).