Adjustable Depth-of-Drive Mechanism for Fastener Tools

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Solution Overview

Problem

Existing fastener driving tools lack a depth-of-drive adjustment mechanism that offers both fine and gross adjustments, making it difficult to accurately set the depth of drive, and often lose their desired position due to repeated tool impact.

Innovation Solution

An adjustable depth-of-drive mechanism with a rotatable thumbwheel assembly and detent system that allows for both fine and gross adjustments, featuring a threaded engagement between the thumbwheel and work contact elements, ensuring the adjustment remains stable despite repeated impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a detent engaging a rotating adjuster is used for fine adjustment, then adjustment precision is improved, but reliability deteriorates due to position loss from repeated tool impact

Engineering Contradiction:
Improvedepth of drive adjustment precisionVSAvoidadjustment position stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the traditional detent-based mechanical fine adjustment system with a threaded rod and thumbwheel assembly. The threaded engagement between the threaded rod and the adjuster provides both fine adjustment capability and positional stability, eliminating the position loss issue inherent in detent systems subjected to repeated impact.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a lockable drive probe mechanism is used for gross adjustment, then ease of operation is improved, but measurement precision deteriorates due to inability to achieve accurate depth settings

Engineering Contradiction:
Improvedepth adjustment operationVSAvoiddepth of drive accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent merges the gross adjustment function (threaded rod rotation) and fine adjustment function (thumbwheel rotation) into a single integrated mechanism. The user can first perform gross adjustment by rotating the thumbwheel to move the drive probe to the approximate position, then perform fine adjustment by rotating the thumbwheel further to achieve precise depth setting, all while the mechanism remains locked in position.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the adjustment mechanism is made accessible and easy to manipulate, then ease of operation is improved, but device complexity may increase

Engineering Contradiction:
Improveadjustment mechanism accessibilityVSAvoidadjustment mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The thumbwheel assembly serves multiple functions: it provides both gross and fine adjustment capabilities, acts as a locking mechanism to prevent position loss, and remains accessible throughout the tool's operation. This multi-functionality reduces the need for separate adjustment mechanisms and simplifies the overall device structure.

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 precise and stable depth adjustment, accessible to both experienced and novice users, maintaining the desired position even with continuous tool use.

Implementation Method 1

a threaded engagement between the thumbwheel and work contact elements

Methodology Applied
Scientific EffectThreaded engagement: Screw

Implementation Method 2

detent system that allows for both fine and gross adjustments

Methodology Applied
Scientific EffectDetent engagement: Ratchet

Data Source

PatentEP1945407B1Adjustable depth-of-drive mechanism for a fastener driving tool
Publication Date: 2020.07.15 ILLINOIS TOOL WORKS INC
  • EP1945407B1 patent drawingFigure 1
  • EP1945407B1 patent drawingFigure 2
  • EP1945407B1 patent drawingFigure 3~4

AI summary

An adjustable depth-of-drive mechanism (10) for a fastener driving tool (11) having a housing structure (12) defining an axis, and a nosepiece (14) extending generally axially from the housing structure, includes a lower work contact element (20) having a sleeve (22) for reciprocatingly receiving the nosepiece, an upper work contact element (16) attached at a first end to the housing structure, a rotatable thumbwheel assembly (24) having a first portion (26) engageable with the lower work contact element (20) , a thumbwheel (28) assembly accessible by a user and a second portion (30) having at least one detent assembly (32) , and a retaining mechanism (44) for retaining the thumbwheel assembly relative to the upper work contact element where the second portion is received by a second end of the upper work contact element, where during thumbwheel rotation relative to the first portion in either direction, the position of the lower work contact element is moved relative to the nosepiece.