Retractable Probe Assembly for Damage-Free Fastener Locating

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Solution Overview

Problem

Existing fastener driving tools with fixed or pivotable locating probes often damage workpieces during the fastener driving process, causing an undesirable aesthetic appearance due to the probe creating a larger impact area than the fastener head.

Innovation Solution

A retractable probe assembly that slides and pivots relative to the workpiece contact element (WCE), tensioned by a low-tension spring, allowing full retraction of the probe to align with the WCE end or behind it, minimizing contact with the workpiece during fastener driving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed or pivotable locating probe is used at the end of the workpiece contact element, then the probe can locate the desired position on the workpiece, but the probe causes damage to the workpiece area adjacent to the fastener head, resulting in poor aesthetic appearance

Engineering Contradiction:
Improvelocating precisionVSAvoidworkpiece damage
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The locating probe is made retractable relative to the workpiece contact element, transitioning from a static fixed or pivotable probe to a dynamic retractable one. The probe can be retracted to align with the end of the WCE or positioned behind it, eliminating contact with the workpiece during fastener driving while maintaining locating capability when extended.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The probe performs the locating action in advance before the fastener driving process. The probe is extended to locate the desired position on the workpiece, then retracted before the fastener is driven, separating the locating function from the driving function and preventing damage during the actual fastening operation.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the locating probe remains extended during fastener driving, then locating is simplified, but the probe creates a larger impact area than the fastener head, damaging the workpiece

Engineering Contradiction:
Improvelocating easeVSAvoidworkpiece damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The probe is designed to be dynamically retractable rather than permanently extended. A spring mechanism provides the force to retract the probe, allowing it to be extended for locating and then retracted for fastening, combining ease of locating with prevention of workpiece damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locating and fastening functions are separated in time through the retractable probe mechanism. The probe handles locating independently first, then retracts to allow the fastener to be driven separately, dividing the operation into distinct phases that avoid interference and damage.

Inventive Principle:
Principle #1Segmentation

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 retractable probe assembly prevents damage to the workpiece by ensuring the probe is fully retracted during the fastener driving process, maintaining the aesthetic integrity of the workpiece and optimizing drive energy transfer.

Implementation Method 1

the probe assembly is tensioned by a low-tension spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4491337B1Fastener driving tool having a retractable probe assembly
Publication Date: 2026.02.11 ILLINOIS TOOL WORKS INC
  • EP4491337B1 patent drawingFigure 1
  • EP4491337B1 patent drawingFigure 2
  • EP4491337B1 patent drawingFigure 3

AI summary

A fastener driving tool including a retractable probe assembly that includes a probe configured to pivot, tensioned by a low-tension spring, and that includes additional probe movement slot that provides for additional movement of the probe, such that retractable probe assembly minimizes damage to the workpiece.