Split Drill Bit Reciprocating Motion for Low-Force Bone Drilling

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Solution Overview

Problem

Conventional drilling systems, such as those using twist drills, are limited in medical applications due to their inability to drill through skin without causing damage and generate excessive heat, and alternative systems like biometric drills require high axial force and can result in uncontrolled movements.

Innovation Solution

A drilling system employing two drilling segments with non-circular cross-sections and a pendulum stroke mechanism, allowing for controlled drilling with low axial force and the ability to produce non-round bore geometries, along with a mechanically simple drive system that can be configured for various driving sequences and geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a twist drill is used for drilling, then a rotating cutting motion is achieved, but the skin wraps around the drill bit and localized heating occurs

Engineering Contradiction:
Improvedrilling capabilityVSAvoidskin wrapping and localized heating
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The drill tip is divided into two separate drilling segments that can move independently relative to each other. This segmentation allows the drill to penetrate material through alternating linear movements of the segments rather than continuous rotation, preventing skin wrapping and reducing localized heating while maintaining effective cutting action.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using rotational motion as the primary drilling mechanism, the invention inverts the approach by using linear reciprocating motion of the drilling segments. The segments move back and forth in straight lines, cutting through material during the forward stroke and retracting during the return stroke, thereby eliminating the harmful effects of rotation on soft materials like skin.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of manufacture

If a biometric drill with two drill tips is used, then drilling can be performed, but uncontrolled movement is exerted on the workpiece and high axial force is required

Engineering Contradiction:
Improvedrilling functionVSAvoidaxial force requirement
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The drilling segments are designed with dynamic movement characteristics, allowing them to oscillate and adjust their positions relative to each other during drilling. This dynamic behavior reduces the static axial force requirement by distributing the cutting load across alternating segments, enabling controlled drilling with lower overall force application to the workpiece.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If a biometric drill with two drill tips is used, then drilling can be performed, but uncontrolled movement is exerted on the workpiece

Engineering Contradiction:
Improvedrilling operationVSAvoidworkpiece stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The guide sections and guide elements create a feedback mechanism that constrains the movement of drilling segments. As each segment advances and retracts, the guide elements ensure that movements remain controlled and predictable, preventing uncontrolled displacement of the workpiece while maintaining stable drilling operation.

Inventive Principle:
Principle #23Feedback

4Shape

If conventional spiral drilling is used, then round bores are produced, but holes cannot be drilled into materials like skin or bone without damage

Engineering Contradiction:
Improvebore geometryVSAvoidmaterial damage
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

By segmenting the drill tip into two independently moving parts, the system can create non-circular bore geometries that are better suited for certain materials. The alternating linear motion of segments produces cutting patterns that differ from conventional rotary drilling, enabling penetration of skin and bone without the wrapping and heating problems associated with circular cutting motions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3827918A1Drilling system
Publication Date: 2021.06.02 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3827918A1 patent drawingFigure 1~3
  • EP3827918A1 patent drawingFigure 4a~5c
  • EP3827918A1 patent drawingFigure 6a

AI summary

The invention relates to a drilling system with a drilling instrument (12) comprising a drive (18) that drives a drilling tool (14) comprising a split drill bit (27), wherein the drilling tool (14) has two drilling segments (29) forming a drill head (31) with a common drill bit (27) and having an outer circumference that deviates from a circular cross-section, wherein each drilling segment (29) has a cutting section (41) and a guide section (42) that are adjacent to one another, and guide elements (45) are provided on the adjacent guide sections (42) of the drilling segments (29) by means of which the guide sections (42) are connected to one another, and a method for driving a drilling tool of such a drilling system. (See Figure 6b)