Rotatable Depth Adjustment Mechanism for Fastener-Driving Tools

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Solution Overview

Problem

Conventional fastener-driving tools face challenges in maintaining depth adjustment during operation due to shock forces and the need for tools to secure fasteners, leading to loosening and variability in depth settings, and existing solutions fail to provide secure retention without compromising component strength or adding weight.

Innovation Solution

An adjustable depth of drive assembly featuring a rotatable adjustment member with locking detents and a compression spring, allowing for tool-free adjustment and secure retention of the workpiece contact element relative to the wire form linkage, ensuring stability during fastener driving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded fasteners are used to secure the workpiece contact element, then the depth adjustment can be secured, but the adjustment requires tools and the fasteners loosen under shock forces

Engineering Contradiction:
Improvedepth adjustment retentionVSAvoidadjustment convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The rotatable adjustment member incorporates a locking detent that automatically engages with a locating hole in the wire form when the adjustment member is rotated to the desired position. This self-locking mechanism eliminates the need for separate fasteners and tools, while maintaining secure retention under shock forces generated during fastener driving.

Inventive Principle:
Principle #25Self-service

2Reliability

If grooves are added to increase adhesion between plates, then the fastener retention improves, but the component strength decreases

Engineering Contradiction:
Improvefastener retentionVSAvoidcomponent strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The locking detent on the rotatable adjustment member automatically engages with the locating hole to provide self-retention, eliminating the need for additional grooves or adhesion features that would compromise component strength while still ensuring reliable fastener retention under operational shock forces.

Inventive Principle:
Principle #25Self-service

3Reliability

If the plates are made thicker to allow deeper grooves, then the adhesion increases, but the tool weight increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidlinkage weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The locking detent mechanism provides reliable retention without requiring deeper grooves or thicker plates, thereby maintaining optimal component weight while ensuring sufficient adhesion and retention strength for the fastener driving application.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If a fluted threaded barrel is used for depth adjustment, then the adjustment is tool-free, but the impact forces cause unwanted movement

Engineering Contradiction:
Improveadjustment convenienceVSAvoiddepth adjustment stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The rotatable adjustment member incorporates a locking detent that automatically engages with a locating hole in the wire form, providing self-retention that prevents unwanted movement caused by impact forces during fastener driving, while maintaining tool-free adjustability.

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 secure and tool-free depth adjustment, maintaining the desired position even under extreme operational forces, enhancing user convenience and component durability without increasing tool weight.

Implementation Method 1

a spring configured to axially bias the rotatable adjustment member towards the locking member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1934018B1Tool-less rotatable depth adjustment for fastener-driving tool
Publication Date: 2021.02.24 ILLINOIS TOOL WORKS INC
  • EP1934018B1 patent drawingFigure 1
  • EP1934018B1 patent drawingFigure 2
  • EP1934018B1 patent drawingFigure 3~4

AI summary

An adjustable depth of drive assembly (10) for use with a fastener driving tool (12) includes a workpiece contact element (26) having a contact end (30) and an adjustment end (28) , a rotatable adjustment member (34) configured for being securable to the tool and being displaceable between an adjusting position in which the workpiece contact element is movable relative to the tool and a locked position wherein the adjustment end is non-movable relative to the tool, and at least one locking detent (50) being reciprocally engaged and disengaged from at least one locating hole (72) by manually overcoming a spring (60) bias to displace the rotatable member from said locked position to said adjustment position for securing said adjustment end in a selected locked position relative to said housing without the use of tools.