Segmented Clamping Tongues for Precise Tool Attachment Centering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing fastening devices for hand-held power tools, such as drills, often result in imprecise centering of attachments due to uneven pressure distribution, leading to misalignment with the tool.

Innovation Solution

The design features clamping tongues that extend circumferentially, with one end merging into the clamping area and protruding radially, allowing for precise centering through a continuous circumferential centering ring and clamping via the clamping tongues, which are pressed inward by the clamping element, ensuring secure attachment without affecting centering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If longitudinal slots are used to form clamping tongues, then the clamping function is achieved, but the centering precision deteriorates due to uneven pressure distribution

Engineering Contradiction:
Improveclamping functionVSAvoidcentering precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The clamping area is segmented into multiple independent clamping tongues that are distributed around the circumference. Each clamping tongue can be independently adjusted by the clamping element, allowing for even pressure distribution across the entire circumference, thereby achieving both reliable clamping and precise centering simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the ring section are given different functions: the clamping tongues are designed with greater thickness to provide localized clamping force, while the centering ring area is designed with uniform thickness to provide continuous centering support. This local differentiation allows each region to optimize its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

2Reliability

If the clamping element presses the ring section against the clamping neck, then secure attachment is achieved, but the centering accuracy deteriorates due to deformation

Engineering Contradiction:
Improveattachment securityVSAvoidcentering accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The clamping force is applied through segmented clamping tongues rather than a continuous clamping area. This segmentation allows the clamping force to be distributed at discrete points, preventing continuous deformation of the ring section that would compromise centering accuracy, while still achieving secure attachment through the cumulative effect of multiple clamping points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping tongues act as intermediaries between the clamping element and the clamping neck. They concentrate the clamping force at specific points while their greater thickness provides structural support, preventing the ring section from deforming in a way that would affect centering accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If the clamping tongue extends in the circumferential direction, then the clamping force is improved, but the structural complexity increases

Engineering Contradiction:
Improveclamping forceVSAvoidstructural complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The clamping tongues are merged with the ring section as an integrated structure, with the clamping tongues being continuous extensions of the ring section material. This merging eliminates the need for separate components or complex assembly operations, achieving enhanced clamping force through a simple, unified structure that is straightforward to manufacture.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1749620B1Fixing mechanism for an attachment for a hand-held machine tool
Publication Date: 2009.02.11 NAREX CESKA LIPA A S
  • EP1749620B1 patent drawingFigure 1
  • EP1749620B1 patent drawingFigure 2
  • EP1749620B1 patent drawingFigure 3~4

AI summary

The attachment can be an angle adapter (5) and is to be temporarily joined to the tool (1) accommodating the drive and serving as a handle. A drive shaft (2) exceeds from the collar (4) at the tool (1) and can be coupled with a complementary part at the attachment (5). A ring unit (14) located at the attachment (5) is pushed onto the collar (4) and secured with a clamping device (23) positioned adjacent to the ring (14) and provided with two inner clamping tongues. The clamping device (23) is tightened or released with a curved lever (32).