Adjustable Boring Bar Cartridge for Straight-Line Insert Positioning

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Solution Overview

Problem

Existing boring bar assemblies with adjustable cartridges face challenges in achieving precise, rectilinear displacement of cutting edges along the radial axis due to curved adjustment mechanisms, which complicates positional adjustments and limits accuracy in cutting operations.

Innovation Solution

A micrometrically adjustable cartridge design featuring a support structure with an L-shaped section and a mechanism incorporating a spring and wedge, allowing for translational movement and precise adjustment of the cutting insert along a straight line, independent of radial displacement, using a combination of bolts and springs to maintain alignment and facilitate precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cam or displacement spindle mechanism is used to adjust the cutting edge position, then the cartridge can be actuated to pivot or bend, but the cutting edge cannot be displaced strictly rectilinearly along the radial axis

Engineering Contradiction:
Improveadjustment mechanism actuationVSAvoidrectilinear displacement precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The adjustment mechanism is segmented into independent functional components: a wedge member for radial positioning and a cam member for axial positioning. This segmentation allows each component to control one degree of freedom independently, enabling rectilinear motion of the cutting edge along the radial axis without the coupling effects present in integrated curved mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a dimensional separation between adjustment functions by positioning the wedge member and cam member in different spatial orientations. The wedge member operates in the radial dimension while the cam member operates in the axial dimension, allowing independent control of cutting edge position in each dimension and achieving pure rectilinear adjustment.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the attachment point is positioned at some distance from the cutting edge, then the cartridge structure can accommodate adjustment mechanisms, but the adjustment follows a curved path rather than a straight line

Engineering Contradiction:
Improvecartridge assembly configurationVSAvoidcutting edge position accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The wedge member acts as an intermediary between the adjustment screw and the cutting insert, converting rotational motion into precise rectilinear motion. This intermediary mechanism eliminates the curved path problem by providing a direct mechanical translation path through the wedge geometry, ensuring that adjustment screw rotation produces only radial displacement without axial or tangential components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If a curved line of travel is used for insert displacement, then the adjustment mechanism can be compact, but it requires modification of the cutting edge position about the radial axis together with modification along the boring bar axis

Engineering Contradiction:
Improveadjustment mechanism compactnessVSAvoidpositional adjustment complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The invention employs dynamic adjustment mechanisms where the wedge member and cam member can independently vary the cutting edge position in different dimensions. This dynamic control allows compact packaging of adjustment functions while maintaining simple, independent control of radial and axial positions, eliminating the coupled complexity of curved path adjustments.

Inventive Principle:
Principle #15Dynamics

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

This design enables precise, micrometric adjustment of the cutting edge's position along the radial axis of the boring bar, enhancing the accuracy and reliability of cutting operations by ensuring straight-line displacement, thus overcoming the limitations of curved adjustment mechanisms.

Implementation Method 1

a first elastic means (5a) arranged to exert force against a first surface (3a) of the load-bearing structure (3)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an adjustment part (5b) disposed between the support structure (2) and a second surface (3b) of the load-bearing structure (3) and arranged to contact and to be movable translationally in a second direction (II) relative to the support structure (2) and the load-bearing structure (3), the adjustment part (5b) having a surface (11) forming an acute angle with the second direction (II)

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP3687721B1Adjustable cartridge for boring bar
Publication Date: 2023.01.04 SECO TOOLS TOOLING SYST
  • EP3687721B1 patent drawingFigure 1~2
  • EP3687721B1 patent drawingFigure 3~4
  • EP3687721B1 patent drawingFigure 5~6

AI summary

An adjustable cartridge (1) for a boring bar includes a support structure (2) including an surface for abutment (2a) with a peripheral area of a boring bar (13); a load-bearing structure (3) for a cutting insert (4) assembled to be movable in a first direction on the support structure (2), characterized in that the cartridge includes: a mechanism to adjust the position of the load-bearing structure (3) in relation to the support structure (2), the adjustment mechanism including at least a first elastic means (5a) arranged to exert force against a first surface (3a) of the load-bearing structure (3), and an adjustment part (5b) disposed between the support structure (2) and a second surface (3b) of the load-bearing structure (3) and arranged to contact and to be movable in a second direction relative to the support structure (2) and the load-bearing structure (3), the adjustment part (5b) having a surface (11) forming an acute angle with the second direction and being disposed in contact with a second surface (3b) of the load-bearing structure (3), the first surface (3a) and the second surface (3b) of the load-bearing structure (3) facing in generally opposite directions.