Push Button Holesaw Mandrel Friction Face Mechanism

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Solution Overview

Problem

Existing holesaw mandrel assemblies do not facilitate quick and easy removal of small diameter holesaws, requiring tools for loosening due to the lack of pin registration and torque engagement, which complicates manual handling.

Innovation Solution

A mandrel assembly with a friction face that moves axially between a contact and release position, enabled by a push button mechanism and rollers, allowing for automatic return to the contact position, allowing for easy removal of holesaws without tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pins are used to secure the holesaw on the mandrel assembly, then the holesaw can be held in position during rotation and cutting, but the holesaw can be easily rotated and removed by hand without tools

Engineering Contradiction:

Improvesecuring forceVSAvoidremoval difficulty

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The friction face is made movable rather than fixed, allowing it to dynamically transition between a first position (contacting the holesaw base to provide securing force) and a second position (retracted to allow removal). This dynamic adjustment resolves the contradiction by enabling both strong securing during operation and easy removal when needed.

Inventive Principle:

Principle #15Dynamics

2Strength

If the holesaw is torqued down onto the collar, then the holesaw is securely held, but a wrench is required to loosen the holesaw for removal

Engineering Contradiction:

Improvesecuring forceVSAvoidremoval difficulty

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The friction face transitions from a static torqued-down configuration to a dynamic system where the friction face can be axially moved. When moved to the second position, the friction face releases the holesaw without requiring external tools, resolving the contradiction between secure holding and easy removal.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the friction face is moved axially to the release position, then the holesaw can be easily removed, but the friction face must return to its original position for the next use

Engineering Contradiction:

Improveremoval easeVSAvoidmechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The biasing mechanism automatically returns the friction face to its first position after the holesaw is removed, without requiring manual intervention. This self-service feature resolves the contradiction by enabling easy removal while automatically resetting the system for the next use, minimizing the perceived complexity for the user.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

A biasing mechanism (such as a spring) replaces complex manual resetting procedures, providing automatic return of the friction face to its operational position. This substitution resolves the contradiction by automating the reset process, making the system easier to use despite the added mechanical component.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If small diameter holesaws are used, then the base diameter is too small to register with the pins, but the threaded engagement requires a wrench for removal

Engineering Contradiction:

Improveholesaw size compatibilityVSAvoidremoval difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The friction face provides a universal securing mechanism that works with holesaws of various diameters, including small diameter holesaws that cannot accommodate pins. The friction-based contact replaces the pin registration system, enabling both small and large holesaws to be securely held and easily removed without tools, resolving the contradiction between size adaptability and removal ease.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables quick and tool-free removal of holesaws from the mandrel assembly, improving user convenience and efficiency, especially for small diameter holesaws.

Implementation Method 1

The mechanism is biased to return the first member to its first position from its second or released position

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

At least one roller is positioned between the first and second member

Methodology Applied

Scientific EffectRoller: Roller

Implementation Method 3

The friction surface is adapted to contact or engage a base surface of the holesaw

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8038372B2Push button holesaw mandrel assembly

Publication Date: 2011.10.18 BLACK & DECKER CORP

AI summary

A holesaw mandrel assembly has a mandrel body with a first end to be coupled with a drill motor and a second end extending from the body. The second end receives a holesaw. A housing covers a portion of the mandrel. A first member is coupled with the housing and moves between a first and second position. A friction surface is on the first member. The friction surface is adapted to contact the holesaw such that upon contact with the friction surface, the holesaw is fixed in position. The friction surface moves between a first contact position and a second release position. A mechanism coupled with the housing moves the friction face between the first and second positions.