Drill And Reamer Coupling With Wedge Locking For Accurate Centering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conical coupling arrangements for drills and reamers face challenges in achieving accuracy and strength due to the need for expensive grinding of conical surfaces, difficulty in adjusting the angle for optimal performance, and a short coupling length that affects machining throw.

Innovation Solution

A coupling arrangement featuring tool and shank portions with axial stoppers, a cylindrical coupling end, and an elongated coupling member, where the tool coupling end abuts the shank axial stopper and the coupling member is wedged between the tool coupling end and a bore recess, allowing for a longer coupling length and adjustable abutment angles to enhance accuracy and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conical surfaces are used for coupling, then centering and torque transfer are achieved, but manufacturing cost increases due to expensive grinding

Engineering Contradiction:
Improvecentering accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The coupling interface is segmented into a cylindrical portion and a conical portion. The cylindrical portion provides centering and location, while the conical portion provides torque transfer. This segmentation allows each portion to be optimized independently, with the cylindrical portion being easier and cheaper to manufacture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a cylindrical surface instead of a fully conical surface for the coupling interface. The cylindrical geometry is simpler to manufacture than conical surfaces requiring expensive grinding, while still achieving the necessary centering and location functions when combined with the conical torque transfer portion.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If the conical angle is increased to strengthen the conical seat, then structural strength improves, but coupling accuracy decreases

Engineering Contradiction:
Improveconical seat strengthVSAvoidcoupling accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The coupling interface is divided into functional segments: the cylindrical portion handles centering and location with high precision, while the conical portion handles torque transfer. This allows the conical angle to be optimized for strength without compromising the accuracy provided by the cylindrical portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of relying entirely on the conical surface for both centering and torque transfer, the invention uses the cylindrical surface for centering and location, and only the conical surface for torque transfer. This partial action approach allows the conical portion to be designed for maximum strength.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If the coupling region length is increased to reduce throw, then machining accuracy improves, but the overall coupling design becomes more complex

Engineering Contradiction:
Improvemachining throwVSAvoidcoupling design complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coupling interface is segmented into cylindrical and conical portions with distinct functions. The cylindrical portion provides precise centering over a sufficient length to control throw, while the conical portion provides torque transfer. This segmentation achieves the required precision without excessive overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cylindrical geometry of the coupling interface simplifies the overall design compared to a fully conical interface. The cylindrical portion provides the necessary length for controlling throw while maintaining geometric simplicity and ease of manufacture.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 improves the accuracy and strength of the coupling, reduces machining throw, and allows for easier assembly and disassembly while maintaining axial alignment, enhancing the overall performance and reliability of the drill and reamer tools.

Implementation Method 1

The member coupling end is wedged between the tool coupling end and the bore recess

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the tool coupling end abuts the front and rear sub-portions, and the member coupling end is wedged between the tool coupling end and the bore recess

Methodology Applied
Scientific EffectNormal force: Force

Implementation Method 3

the tool axial stopper abuts the shank axial stopper

Methodology Applied
Scientific EffectContact force: Force

Implementation Method 4

the member coupling end is wedged between the tool coupling end and the bore recess

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Data Source

PatentEP3288703B1Tool coupling arrangement for drills and reamers
Publication Date: 2022.11.23 ISCAR LTD
  • EP3288703B1 patent drawingFigure 1~2
  • EP3288703B1 patent drawingFigure 3~4
  • EP3288703B1 patent drawingFigure 5~6

AI summary

A tool coupling arrangement (12) for drills and reamers includes tool and shank portions (14,16) with respective tool and shank axial stoppers (46,48). An at least partially cylindrical tool coupling end (24) of the tool portion (14) is located within a longitudinal through forward bore portion (76) in the shank portion (16), and is coupled therein via an elongated coupling member (18), which is located further inwards in the shank portion (16) and comprises axially opposite member coupling and pulling ends (56,58). The forward bore portion (76) has front and rear sub-portions (76F,76R) and a bore recess (80) which is located therebetween and extends radially outwardly. In a locked position (figures 3 to 6), the tool axial stopper (46) abuts the shank axial stopper (48). The tool coupling end (24) abuts the front and rear sub-portions (76F,76R) and coupling end (56) of the coupling member (18) is wedged between the tool coupling end (24) and the bore recess (80).