Tubular Tool Holder Locking Sleeve Spring Mechanism

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Solution Overview

Problem

Existing tool holders for hand-held power tools lack a secure and reliable locking mechanism for insert tools, leading to potential tool misalignment and reduced user safety.

Innovation Solution

A tool holder with a tubular base body and a locking device featuring a spring-loaded locking sleeve, a blocking element, and a fixing element, which allows for secure and reliable locking of insert tools through a combination of axial and rotational displacement, enabling easy switching between locking and unlocking positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking device with locking sleeve and locking element is provided, then tool retention security is improved, but device complexity increases

Engineering Contradiction:
Improvetool retention securityVSAvoidlocking device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is nested within the locking sleeve, with the locking element positioned inside the hollow cylindrical locking sleeve. This nested arrangement allows both components to occupy the same spatial envelope, reducing overall complexity while maintaining the locking function through the interaction between the locking element's protrusion and the locking sleeve's internal features.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The locking device is segmented into distinct functional components: the locking sleeve with its internal recess and contact surface, and the locking element with its protrusion. This segmentation allows each component to be optimized independently for its specific function while working together to provide secure tool retention.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a spring element is used to actuate the locking sleeve, then automatic locking reliability is improved, but device complexity increases

Engineering Contradiction:
Improveautomatic locking reliabilityVSAvoidspring mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element is integrated directly into the locking sleeve structure, with the spring positioned within the hollow interior of the locking sleeve. This merging of the spring mechanism with the locking sleeve eliminates the need for separate housing structures, reducing overall device complexity while maintaining automatic locking reliability through the spring's direct action on the locking sleeve.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring element is nested within the hollow cylindrical locking sleeve, utilizing the internal space of the locking sleeve for spring accommodation. This nested arrangement allows the spring mechanism to be compact and integrated, avoiding additional external components and reducing structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If the locking element is made displaceable along longitudinal extent, then ease of operation is improved, but reliability may worsen

Engineering Contradiction:
Improvetool insertion and removal easeVSAvoidlocking engagement stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking element is designed with dynamic displacement capability along the longitudinal axis, allowing it to move between locked and unlocked positions. This dynamic feature is complemented by the spring element that provides restoring force, ensuring that the locking element returns to its proper engagement position after displacement, thereby maintaining reliability while enabling ease of operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring element provides self-service by automatically returning the locking element to its engaged position after manual displacement. This self-restoring mechanism ensures that the locking engagement is maintained reliably without requiring additional actuation mechanisms or complex control systems, balancing ease of operation with reliability.

Inventive Principle:
Principle #25Self-service

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 compact, space-saving design that ensures secure tool retention, allowing for easy tool changes and preventing misalignment, thereby enhancing user safety and tool performance.

Implementation Method 1

The locking sleeve is acted upon in a locking position along a longitudinal extension of the base body, which is at least partially tubular, by means of a spring element

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The spring element acts upon the retaining element against the contact element

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP4344827A1Tool holder for a hand-held power tool
Publication Date: 2024.04.03 ROBERT BOSCH GMBH
  • EP4344827A1 patent drawingFigure 1
  • EP4344827A1 patent drawingFigure 2
  • EP4344827A1 patent drawingFigure 3~4

AI summary

In a tool holder (120) for a hand-held power tool, comprising a base body (122) that is at least partially tubular and forms an internal recess (125) for receiving an insert tool (210), in particular a bit insert tool, and comprising a locking device (180) for releasably locking an insert tool (210), in particular a bit insert tool, that can be arranged in the internal recess (125), wherein the locking device (180) comprises a locking sleeve (127) and a locking element (370), the locking sleeve (127) is acted upon in a locking position along a longitudinal extension (199) of the base body (122) that is at least partially tubular by means of a spring element (320).wherein the locking sleeve (127) has at least a section of its inner circumference (308) a contact element (354) and the at least approximately tubular base body (122) has a fixing element (310) on its outer circumference (302), wherein the spring element (320) acts the fixing element (310) against the contact element (354).