Razor Blade Assembly Pre-Form with Disposable Tie

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Solution Overview

Problem

Existing shaving razor cartridges become too rigid during manufacturing, leading to discomfort due to abrupt blade engagement with skin rather than hair, and existing flexible configurations fail to preserve desired blade geometry during attachment.

Innovation Solution

A shaving blade assembly pre-form method involving a blade frame with transverse connecting strips, welded blades, and a disposable tie that anchors the frame to maintain blade geometry by preventing buckling and splaying, ensuring the blades maintain their intended progressive geometry and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If blades are welded to a rigid blade frame during manufacturing, then manufacturing precision and blade alignment are improved, but the razor becomes too rigid causing abrupt blade engagement with skin leading to nicks and cuts

Engineering Contradiction:
Improveblade alignmentVSAvoidshaving comfort
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The blade frame is segmented into multiple rigid sections (blade supports, connecting strips) that are individually precise, while the overall assembly allows relative movement between these segments. This enables the frame to maintain manufacturing precision for blade alignment while accommodating flexibility for comfortable shaving through the compliant mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade frame transitions from a completely rigid structure to a dynamically compliant structure that can adapt during operation. The frame incorporates compliant mechanisms that allow controlled movement and deformation during shaving, enabling the blade to follow skin contours while maintaining precise alignment through the designed compliance paths.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a flexible blade support structure is used to provide comfort, then shaving comfort is improved, but blade geometry and alignment cannot be preserved during attachment

Engineering Contradiction:
Improveshaving comfortVSAvoidblade geometry
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The blade geometry is precisely established and secured during the welding attachment process before the compliant mechanism is activated. The blade is welded to the blade support in its exact desired position and orientation, preserving progressive blade geometry. Subsequently, the compliant mechanism allows movement that maintains this pre-established geometry while providing flexibility during shaving.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Different parts of the blade frame have different properties: the blade support and connecting strips provide rigid, precise positioning for manufacturing accuracy, while other portions incorporate compliance for flexibility. The blade is locally secured with high precision at the welding interface, while the overall structure allows global movement for comfort.

Inventive Principle:
Principle #3Local quality

3Productivity

If multiple blades are attached to the blade frame, then productivity is improved, but distortion of the blade frame occurs during attachment process

Engineering Contradiction:
Improveblade attachment efficiencyVSAvoidframe distortion
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The blade frame is pre-configured with blade supports and connecting strips in their exact final positions before blade attachment. This preliminary arrangement ensures that when multiple blades are welded to the frame, the frame already has the correct geometry and alignment, preventing distortion during the attachment process and enabling efficient multi-blade assembly.

Inventive Principle:
Principle #10Preliminary action

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

The method effectively prevents distortion of the blade frame and maintains the desired blade geometry during attachment, enhancing the shaving experience by ensuring a close shave without nicks, and facilitating the incorporation of the blade assembly into a cartridge with minimal distortion.

Implementation Method 1

a disposable tie disposed parallel to said plurality of blades and across said transverse connecting strips

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

a plurality of blades welded to the blade frame that span the transverse connecting strips

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2219829B1Razor blade assembly pre-form
Publication Date: 2014.03.26 THE GILLETTE CO
  • EP2219829B1 patent drawingFigure 1
  • EP2219829B1 patent drawingFigure 2
  • EP2219829B1 patent drawingFigure 3A~3B

AI summary

A shaving blade assembly pre-form (5) comprising a blade frame (10) comprising transverse connecting strips (15); a plurality of blades (35) welded to the blade frame that span the transverse connecting strips along a length of the frame; and a disposable tie (18) disposed parallel to the plurality of blades and across said transverse connecting strips.