Trapezoidal Utility Blade with Score Lines and Indexing Notches

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Solution Overview

Problem

Conventional utility knife blades with trapezoidal shapes dull quickly, leading to increased replacement costs and material waste, and manual snapping techniques are cumbersome and unsafe, while existing snap-off style blades require specialized holders and cannot be used with conventional knives.

Innovation Solution

A utility knife blade with a trapezoidal peripheral configuration and score lines that allow for the removal of segments, providing multiple cutting points and indexing notches for consistent blade extension, compatible with both retractable and fixed blade utility knives, reducing waste and enhancing user control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional trapezoidal utility blades are used, then the blade can be used with standard utility knives, but the blade tips dull quickly requiring frequent replacement

Engineering Contradiction:

Improveblade lifeVSAvoidmaterial waste

Core Design Contradiction:

Duration of action of moving objectVSLoss of substance

Solution Approach 1:

The blade is divided into multiple segments by score lines, allowing the user to snap off only the dulled tip segment while retaining the rest of the blade. This segmentation enables partial reuse of the blade body, extending overall blade life and reducing material waste from complete blade replacement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Score lines are pre-formed on the blade during manufacturing at predetermined locations. These preliminary structural weak points enable controlled snapping at specific locations, allowing users to renew the cutting tip without manual force or tools, thereby extending blade usability.

Inventive Principle:

Principle #10Preliminary action

2Ease of repair

If manual snapping of dulled tips is attempted, then the blade can be renewed, but the process is cumbersome and creates safety hazards

Engineering Contradiction:

Improveblade renewal easeVSAvoidsafety hazard

Core Design Contradiction:

Ease of repairVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The score lines act as intermediaries that facilitate controlled blade tip removal. Instead of directly applying force to the blade tip (which causes uncontrolled shattering), the score lines serve as predetermined failure points that guide the snapping process, reducing safety hazards.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Duration of action of moving object

If snap-off style utility blades with multiple segments are used, then blade life is extended, but specialized blade holders are required

Engineering Contradiction:

Improveblade lifeVSAvoidblade holder complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The blade maintains a substantially trapezoidal peripheral configuration that is compatible with conventional utility knife holders. This universal geometry allows the blade to function in standard holders without requiring specialized indexing mechanisms, while still providing multiple cutting points through score lines.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of designing a specialized holder to manage multiple blade segments, the invention inverts the approach by making the blade itself adaptable to conventional holders. The blade's trapezoidal shape ensures compatibility with standard holders, while the score lines provide the multi-segment functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

4Productivity

If blade segments are removed to create new cutting points, then more cutting points are available, but consistent blade extension and stability are difficult to maintain

Engineering Contradiction:

Improvenumber of cutting pointsVSAvoidblade stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7921568B2Four point utility blade

Publication Date: 2011.04.12 BLACK & DECKER CORP

AI summary

A utility blade for use with conventional retractable and fixed blade utility knives comprising a blade body having a generally trapezoidal configuration defined by a cutting edge, an opposite back edge, a pair of opposing side edges and a pair of cutting points defined by the points of intersection between the side edges and the cutting edge. The blade further defines a pair of score lines, each proximate to one of the side edges. The score lines enable the user to remove a dulled or damaged cutting point, which in turn provides the user with two additional cutting points defined by the points of intersection between the score lines and the cutting edge. Further, the blade is configured with one or more notches strategically located on the back edge of the blade, such that each cutting point can extend from the utility knife at approximately the same distance.