Utility Knife Connector With Segmented Head And Threaded Shaft

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Solution Overview

Problem

Existing utility knives lack a secure and efficient mechanism for connecting and disconnecting their handle portions, which can lead to accidental separation and difficulties in tool-free assembly or disassembly.

Innovation Solution

A utility knife design featuring a connector member with a head portion and shaft portion, including finger engaging portions and a groove for tool engagement, allowing for tool-free rotation and secure attachment to one handle portion even when the other is separated, using a combination of threaded and non-threaded components for reliable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a threaded fastener is used to connect handle portions, then the connection strength is improved, but the ease of assembly and disassembly deteriorates due to requiring tools

Engineering Contradiction:
Improveconnection strengthVSAvoidease of assembly and disassembly
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connector member is segmented into a head portion and a shaft portion, allowing the head to provide manual engagement features while the shaft provides the threaded connection function. This segmentation enables the fastener to be operated manually at the head portion while maintaining threaded connection strength through the shaft portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The head portion acts as an intermediary between the user's fingers and the threaded shaft portion. The finger engaging portions on the head allow manual rotation without tools, while the shaft transmits this rotational motion to achieve the threaded connection, mediating between manual operation and threaded fastening.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If a conventional fastener design is used, then the manufacturing simplicity is improved, but the reliability of secure attachment deteriorates due to accidental separation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidreliability of secure attachment
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The shaft portion is designed with a length that extends beyond the first handle portion, creating a preliminary secure attachment state. This extended shaft ensures that even if the second handle portion is separated, the connector remains reliably attached to the first handle portion, preventing accidental complete separation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connector member features asymmetric design where the head portion has finger engaging portions for manual operation while the shaft portion has threaded features for secure attachment. This asymmetry allows differential functionality - manual engagement at one end and secure threaded connection at the other, improving reliability without complicating manufacturing.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If the connector member is designed for tool-free operation, then the ease of operation is improved, but the connection strength may deteriorate

Engineering Contradiction:
Improvetool-free operationVSAvoidconnection strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The connector member is segmented into a head portion and a shaft portion, allowing the head to provide manual engagement features while the shaft provides the threaded connection function. This segmentation enables the fastener to be operated manually at the head portion while maintaining threaded connection strength through the shaft portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector member combines different functional features in a composite structure - the head portion with finger engaging portions for manual operation and the shaft portion with threaded features for strong connection. This composite design integrates both manual operability and strong connection capability in a single component.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2409817B1Utility knife and fastener thereof
Publication Date: 2016.03.16 STANLEY BLACK & DECKER INC
  • EP2409817B1 patent drawingFigure 1~2
  • EP2409817B1 patent drawingFigure 3~6
  • EP2409817B1 patent drawingFigure 7

AI summary

A utility knife (10) includes a handle (12) and a connector member (14). The handle includes a first handle portion (16) and a second handle portion (18). The connector member is constructed and arranged to releasably connect the first handle portion with the second handle portion. The connector member includes a head portion (20) and a shaft portion (22) extending from the head portion. The head portion includes finger engaging portions (24) extending outwardly for engagement by the fingers of a user, and a groove (26) disposed on a surface (28) of the head portion that is adapted to receive a tool (30) . The connector member is constructed and arranged to be rotated either by engaging the tool in the groove or by manually moving the finger engaging portions. The connector member is constructed and arranged to remain attached to the first handle portion if the first handle portion is separated from the second handle portion.