Reverse Countersink Assembly With Depth Stop for Confined Holes

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Solution Overview

Problem

Existing tools face challenges in performing reverse countersinking in confined or limited spaces due to inconsistent depth of cut and finish.

Innovation Solution

The development of a reverse countersink cutting assembly comprising a countersink cutting head, a depth stop sleeve, and a fastener, which allows for precise control of the depth of cut through projections on the depth stop sleeve, enabling consistent countersinking in tight spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing tools are used for reverse countersinking, then the operation can be performed in confined spaces, but the depth of cut is inconsistent and the cut finish is inconsistent

Engineering Contradiction:
Improvedepth of cut consistencyVSAvoidtool structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tool is divided into separate functional components: a countersink cutting head with cutting portion, a depth stop sleeve with projections, and a fastener. This segmentation allows the depth control mechanism to be independently adjusted without redesigning the entire tool, improving depth of cut consistency while maintaining manageable complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The depth stop sleeve with projections is pre-configured to extend to a predetermined point within the countersink cutting range. This preliminary setup of the depth stop mechanism ensures consistent depth control is built into the tool structure before operation, eliminating the need for operator judgment and achieving reliable depth consistency.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If operator control is used for depth of cut, then the tool is simple to operate, but the depth of cut becomes inconsistent

Engineering Contradiction:
Improvedepth of cut precisionVSAvoidoperator control difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The depth stop sleeve with projections automatically limits the depth of cut by physically stopping the cutting head at the predetermined depth. The tool performs its own depth control function without requiring operator skill or judgment, achieving precise and consistent depth of cut while remaining easy to operate.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The projections on the depth stop sleeve provide immediate physical feedback to the operator by contacting the workpiece surface at the predetermined depth. This tactile feedback signal automatically indicates when the correct depth is reached, ensuring consistent depth control without requiring operator measurement or calculation.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If a predetermined depth stop is implemented, then consistent depth of cut is achieved, but the device complexity increases

Engineering Contradiction:
Improvecut finish consistencyVSAvoidassembly components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The depth stop sleeve is integrated with the countersink cutting head assembly, and the projections are formed as part of the sleeve structure. This merging of the depth control feature into the existing tool components achieves consistent cut finish without requiring separate complex depth control devices, minimizing the increase in overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4534226A1Reverse countersink cutting assembly and method for reverse countersinking a through hole in a workpiece
Publication Date: 2025.04.09 THE BOEING CO
  • EP4534226A1 patent drawingFigure 1
  • EP4534226A1 patent drawingFigure 2
  • EP4534226A1 patent drawingFigure 3

AI summary

A reverse countersink cutting assembly 100 includes a countersink cutting head 102, a depth stop sleeve 118 and a fastener 128. The countersink cutting head includes a cutter distal portion 110, a cutting portion 112 and a cutter proximal portion 114 axially spaced along a longitudinal axis 104. The cutting portion defines a countersink cutting range 116. The depth stop sleeve includes a central cavity 120 that coaxially receives the cutter proximal portion of the countersink cutting head. The depth stop sleeve also includes one or more projections 122 that extend coaxially along the longitudinal axis to a predetermined point 124 within the countersink cutting range to define a depth of cut 126 for the reverse countersink cutting assembly. The fastener retains the depth stop sleeve on the countersink cutting head. A method for reverse countersinking a through hole 202 in a workpiece 204.