Disposable Acetabular Reamer Flat Stock Segmentation

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Solution Overview

Problem

Existing bone cutting tools, such as acetabular reamers, are difficult to manufacture at low cost and often suffer from deformation and high production costs due to the complexity of forming hemispherical shapes, leading to high final costs and potential contamination issues from prior use.

Innovation Solution

A disposable reamer assembly comprising a press-formed, thin-walled cutting body with appendages connected at the center, which is mechanically affixed to a circular base, allowing for improved die forming and minimizing stress-induced deformation, enabling accurate cutting while being easily disassembled for partial disposal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If press-formed hemispherical reamers are made from flat metal stock, then the reamers can be manufactured, but severe working stresses cause deformation and warpage requiring complex expensive machinery

Engineering Contradiction:
Improvemanufacturability of reamerVSAvoidhemispherical form accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The reamer is divided into two separate components: a base component and a cutting body component. The cutting body is formed separately and then attached to the base, allowing each part to be manufactured independently with optimized processes that avoid the deformation problems of forming a complete hemispherical shell from flat stock.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutting body is pre-formed with the desired hemispherical shape and cutting edges before being attached to the base. This preliminary formation allows for controlled shaping without the severe stresses that would occur if the entire hemispherical shell were formed from flat stock in a single press-forming operation.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If complex expensive machinery is used to minimize warpage, then manufacturing precision improves, but production costs increase making the tool non-disposable

Engineering Contradiction:
Improvehemispherical form accuracyVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By segmenting the reamer into a base and a cutting body, the complex press-forming operation is eliminated. The cutting body can be formed using simpler, less expensive processes, and the base can be manufactured separately, allowing for low-cost production that enables disposable use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segmentation and simplified manufacturing process reduce production costs sufficiently to allow the reamer to be designed as a disposable tool. The cutting body with appendages can be mass-produced at low cost, making single-use economically viable and eliminating the need for expensive reconditioning or sterilization infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If the reamer is designed as a single integrated piece, then structural strength is maintained, but cleaning is difficult and cross-contamination risk increases

Engineering Contradiction:
Improvestructural integrityVSAvoidcross-contamination risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The reamer is segmented into a base component and a cutting body component that can be separated. The cutting body, which contacts bone tissue, can be removed and disposed of after a single use, eliminating cross-contamination risk. The base can be retained and reused with a new cutting body attached, maintaining structural integrity while enabling disposable cutting elements.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If the cutting body is made as a thin-walled structure, then material usage is reduced and cost decreases, but the assembly may lack rigidity for cutting bone

Engineering Contradiction:
Improvematerial efficiencyVSAvoidcutting rigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The thin-walled cutting body is segmented from the base structure. The cutting body itself can be made thin-walled to reduce material usage and cost, while the base provides the necessary structural support and rigidity. When assembled together, the combination achieves both material efficiency and sufficient strength for bone cutting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reamer assembly combines the thin-walled cutting body with the base structure to create a composite system. The cutting body uses minimal material for its cutting function, while the base provides structural reinforcement, achieving overall rigidity without requiring the cutting body itself to be thick-walled.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2111168B1Disposable acetabular reamer from flat stock
Publication Date: 2013.03.20 GREATBATCH MEDICAL SA
  • EP2111168B1 patent drawingFigure 1A~1B
  • EP2111168B1 patent drawingFigure 2~3A
  • EP2111168B1 patent drawingFigure 3B~3C

AI summary

A disposable reamer (10) is provided, made up of a base (12) and a thin-walled, perforated cutting body (14) of flat metal stock affixed thereto. The base and body may be molded together or assembled together in a mechanical manner. The body is optionally formed so as to comprise a plurality of appendages connected at a center so as to improve die forming of the body into a final desired shape while at the same time minimizing stress-induced deformation in the body.