Replaceable Blade Knife With Hinged Lid And Retention Feature

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Solution Overview

Problem

Existing utility knives are not efficiently designed for opening packaging materials, particularly boxes and films, as they lack features that facilitate easy blade replacement and exposure of cutting edges.

Innovation Solution

A knife design with a removable cutting head portion and retention feature that allows for easy blade replacement, featuring a trapezoidal blade recess and double-sided cutting head with gaps to expose the cutting edge, and a film splitter for puncturing packaging materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the cutting head portion is made fixed and integrated with the handle, then the structural stability is improved, but the blade replacement becomes difficult and time-consuming

Engineering Contradiction:
Improvestructural stabilityVSAvoidblade replacement ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The knife is divided into separate functional components: a handle portion, a cutting head portion, and a blade. The cutting head portion can be selectively removed from the handle, and the blade can be independently replaced within the cutting head. This segmentation allows stable integration when needed while enabling easy replacement when required.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutting head portion is designed with dynamic retention features that allow it to be selectively retained or removed from the handle portion. This dynamic design transitions the structure from fixed to movable based on operational needs, facilitating both structural stability during use and ease of blade replacement when the cutting head is removed.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the cutting edge is fully enclosed in the cutting head, then safety is improved, but cutting efficiency decreases due to limited exposure

Engineering Contradiction:
ImprovesafetyVSAvoidcutting efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The cutting head portion is designed to be double-sided with gaps that expose cutting edges from multiple directions. This multi-dimensional approach allows the cutting edge to be protected when not in use while providing adequate exposure during cutting operations from different angles, thereby maintaining both safety and cutting efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If a single-sided cutting head is used, then the device complexity is reduced, but the versatility decreases as only one cutting edge can be used

Engineering Contradiction:
Improvecutting head structure complexityVSAvoidcutting edge utilization
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The cutting head portion is designed to be double-sided, providing two cutting edges that can be used alternately. This multi-functional design allows the same cutting head to perform cutting operations from both sides, effectively doubling the usable cutting edges without significantly increasing structural complexity, thereby improving versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If the retention feature is permanently engaged, then the reliability of blade retention is improved, but the ease of blade replacement deteriorates

Engineering Contradiction:
Improveblade retention reliabilityVSAvoidblade replacement ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retention feature is designed to be self-retaining during normal operation, automatically holding the cutting head portion securely to the handle portion. When replacement is needed, the retention feature can be easily disengaged by applying simple pressure or manipulation, allowing the user to service the blade without complex tools or procedures, thus maintaining both reliability and ease of replacement.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3505316B1Knife with replaceable blade
Publication Date: 2020.07.01 STANLEY BLACK & DECKER INC
  • EP3505316B1 patent drawingFigure 1
  • EP3505316B1 patent drawingFigure 2
  • EP3505316B1 patent drawingFigure 3

AI summary

A knife includes a handle portion and a cutting head portion. The cutting head portion includes a lid portion and a base portion configured to receive a blade therebetween. The lid portion is coupled to the base portion by a hinge. Rotation of the lid portion relative to the base portion away from the base portion opens a space above the base portion through which the blade may lifted. A method of removing a blade from a knife includes rotating a lid portion relative to a base portion about a hinge coupling the lid portion to the base portion, further rotating the lid portion until a protrusion fixed to the lid portion extends through the base portion and lifts up on the blade to create a gap between the blade and the base portion, and grasping the blade at the gap to pull the blade away from the base portion.