Rotary Tool Holder with Movable Restraint Elements for Easy Release

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Solution Overview

Problem

Existing holders for rotary tools, such as hole saws, are cumbersome and difficult to disassemble due to complex designs requiring multiple springs, leading to assembly challenges and increased risk of functional disorders, and they often restrict the depth of bore due to larger diameters.

Innovation Solution

A slimmer holder design with a rotationally symmetrical body, featuring a thrust collar and axially movable operating means that allows for either linear or rotational motion to displace restraint elements, reducing the number of components and simplifying assembly, while eliminating thread stresses for easy tool replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a holder uses a complex design with multiple springs and restraint elements to enable tool removal, then the tool can be removed by eliminating thread preload, but the device complexity increases and assembly becomes difficult

Engineering Contradiction:
Improvetool removalVSAvoidholder structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple springs (first spring means acting radially and second spring means acting axially) and restraint elements into a single integrated holder structure. The restraint elements are positioned in spaces within the holder body and work in conjunction with both spring systems to provide tool retention and release functions, merging what could be separate components into one unified device.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The holder employs dynamic restraint elements that can move between different positions. The restraint elements are prevented from radial movement in a first axial position of the operating means and are free to make radial movement in a second axial position, allowing the system to transition between tool retention and tool release states through controlled movement of the restraint elements.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a holder uses a bulky design with larger diameter to accommodate friction means and springs, then tool retention and release functions can be achieved, but the holder limits the possible depth of bore since it will be blocked by the workpiece

Engineering Contradiction:
Improvetool retention and releaseVSAvoidholder diameter
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent utilizes axial dimension for the operation of restraint elements and springs rather than requiring increased radial dimension. The restraint elements move radially within axial spaces, and the operating means moves axially to control this radial movement, effectively using the axial dimension to achieve functions that would otherwise require larger radial clearance.

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

Solution Approach 2:

The restraint elements are nested within spaces in the holder body, and the operating means is positioned within the holder to control these restraint elements. The spring means are arranged to act upon the restraint elements from within the holder structure, creating a nested arrangement where components are contained within one another to minimize overall holder diameter.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If a holder uses numerous components including two types of springs and multiple restraint elements, then functional capability is enhanced, but the number of components increases making assembly difficult and serviceability reduced

Engineering Contradiction:
Improvetool holding and release capabilityVSAvoidassembly simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The holder design integrates multiple functions into unified components. The restraint elements serve dual purposes: they are prevented from radial movement in the first axial position to retain the tool, and are free to move radially in the second axial position to release the tool. The operating means controls both the position of restraint elements and the activation of spring mechanisms, reducing the need for separate dedicated components for each function.

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

4Device complexity

If a holder uses a design requiring diameters greater than hole saw diameters, then friction means and spring mechanisms can be accommodated, but the holder blocks the workpiece and limits drilling depth

Engineering Contradiction:
Improvefriction means and spring mechanismsVSAvoidholder diameter
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent employs thin-walled or compact structural elements in the holder design that provide sufficient strength and functionality while minimizing the outer diameter. The restraint elements and spring mechanisms are arranged to operate within compact spaces, allowing the holder to maintain a slim profile that does not interfere with deep drilling operations.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3448608B1Holder for a rotary tool comprising radially and axially movable restraint elements
Publication Date: 2021.11.24 KAPMAN
  • EP3448608B1 patent drawingFigure 1~2
  • EP3448608B1 patent drawingFigure 3~5b
  • EP3448608B1 patent drawingFigure 6a~7b

AI summary

Holder (10) for a rotary tool (21) which holder (10) is formed with a holder body (100) comprising a rear drive end (11) and a front connection end (12) having a connection thread (13) for the connection of the tool (21). The holder (10) comprises a thrust collar (14, 64) having a flat contact surface (141) facing a connection end (12) of the holder (10). The holder comprises an axially movable operating means (15), a number of restraint elements (16) placed in one or more spaces (17) in the holder body which restraint elements (16) in a first axial position of the operating means (15) are prevented from radial movement in said spaces (17) and which restraint elements (16) in a second axial position of the operating means (15) allow radial movement in said spaces (17). Each one of said spaces (17) for the restraint elements (16) is limited in the axial direction by a front limiting wall (47) as well as by a rear limiting wall (46, 66), which two limiting walls (46, 66, 47) are parts of the holder body (100).