Clamping Collar for Hand-Held Machine Tool Accessories

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Solution Overview

Problem

Handheld power tools lack a flexible and easy-to-use accessory attachment system that allows for secure fastening of accessories at multiple positions, limiting user convenience and tool versatility.

Innovation Solution

A clamping neck around the output shaft of the gear unit, designed to accommodate accessories with a form or force fit, which can be angled and has a profiled surface for secure fastening, combined with a spring-elastic clamping ring for easy attachment and detachment, enabling accessories to be fastened in multiple positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional accessory attachment system is used, then the structure is simple, but the ease of operation and flexibility are poor

Engineering Contradiction:
Improveease of accessory attachmentVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The accessory attachment system is segmented into distinct functional components: the clamping neck (18) as the mounting base, the clamping ring (30) as the fastening mechanism, and the accessory elements (56, 62) as removable attachments. This segmentation allows each component to be optimized independently while maintaining overall simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping ring (30) is designed with spring-elastic properties, enabling it to dynamically expand and contract for easy attachment and detachment of accessories. The ring can be compressed radially inward for installation and automatically expands to engage with the clamping neck, providing dynamic ease of operation without complex mechanisms.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a fixed accessory mounting position is used, then the manufacturing is simple, but the adaptability and versatility are limited

Engineering Contradiction:
Improveaccessory positioning flexibilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The clamping neck (18) features an asymmetric circumferentially profiled outer surface (24) with a groove (54) that creates specific engagement positions. This asymmetric design allows accessories to be mounted at multiple predetermined positions around the output shaft while maintaining simple manufacturing through injection molding or similar processes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The clamping neck (18) serves multiple functions: it provides structural support, defines mounting positions through its profiled surface, enables secure fastening via the groove (54), and accommodates various accessory types. This multi-functionality increases versatility without requiring separate mounting mechanisms for each function.

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

3Reliability

If a secure fastening mechanism is used, then the reliability is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improveaccessory fastening securityVSAvoidattachment and detachment ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spring-elastic clamping ring (30) is designed to automatically engage with the clamping neck (18) when compressed and installed. The elastic force self-generates the securing action, eliminating the need for additional fasteners, tools, or complex locking mechanisms. The ring maintains reliable fastening through its inherent elastic properties while allowing easy manual attachment and detachment.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If multiple accessory positions are allowed, then the versatility increases, but the device complexity increases

Engineering Contradiction:
Improvenumber of accessory positionsVSAvoidmounting mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The clamping neck (18) utilizes the circumferential dimension around the output shaft to provide multiple mounting positions. The profiled outer surface (24) with groove (54) creates discrete angular positions in the circumferential direction, allowing accessories to be mounted at various orientations without adding axial or radial complexity to the mounting mechanism.

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

Data Source

PatentEP2608930B1Hand-held machine tool comprising a clamping collar
Publication Date: 2022.09.07 ROBERT BOSCH GMBH
  • EP2608930B1 patent drawingFigure 1
  • EP2608930B1 patent drawingFigure 2~3
  • EP2608930B1 patent drawingFigure 4~5

AI summary

The invention relates to a hand-held machine tool, comprising a housing (36) and a drive unit, a gearbox unit which is provided to convert a rotary motion of the drive unit into an oscillating motion (10) and has an output shaft (12), and a tool holder (14) for fastening at least one tool (16), said tool holder being drivable in an oscillating manner via the output shaft (12) the gearbox unit. According to the invention, the hand-held machine tool comprises a clamping collar (18), which extends in a circumferential direction (20) at least partially around the output shaft (12).