Safety Knife Blade Change Button and Slide Mechanism

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Solution Overview

Problem

Existing knives with replaceable blades lack an efficient mechanism for transitioning the blade from a storage to a working position and back, making blade replacement cumbersome.

Innovation Solution

A knife design featuring a blade change button with a blocking section that protrudes into the slide's movement path, allowing the slide to be displaced into a blade-changing position by actuating the button, and a coupling element that disengages from a control flank to facilitate blade removal and insertion, with a flexible or rigid coupling element that bends or pivots to enable easy blade exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a blocking section is used to prevent the slide from moving beyond the working position, then the blade remains securely in place during normal operation, but the mechanism for replacing the blade becomes more complex

Engineering Contradiction:
Improveblade securityVSAvoidblade replacement mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A control element acts as an intermediary between the slide and the coupling element. When the slide is in the blade-changing position, the control element engages with a control flank to automatically disengage the coupling element from the drive recess, enabling blade removal without requiring direct manual manipulation of the coupling mechanism itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling element is designed with a control flank that is预先 positioned to engage with the control element on the slide. This preliminary arrangement ensures that when the slide moves to the blade-changing position, the coupling element automatically disengages from the drive recess, preparing the system for blade removal without additional steps.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the coupling element is made rigid to ensure stable blade mounting, then the blade remains firmly secured, but the mechanism for blade replacement becomes more difficult to operate

Engineering Contradiction:
Improveblade mounting stabilityVSAvoidblade replacement ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling element is designed to be movable rather than fixed. It can transition between an engaged state (when the blade is mounted and the slide is in the working position) and a disengaged state (when the slide moves to the blade-changing position and the control element activates the control flank). This dynamic behavior allows the coupling element to maintain stable blade mounting during normal use while enabling easy blade replacement when needed.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the slide is designed to abut the blocking section in the final phase of movement, then the blade is securely positioned in the working position, but the transition to blade-changing position requires additional mechanism complexity

Engineering Contradiction:
Improveblade positioning precisionVSAvoidposition transition mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The slide itself carries the control element that automatically engages with the control flank on the coupling element when the slide reaches the blade-changing position. This self-service mechanism eliminates the need for separate actuating components or complex control systems, as the slide's own movement triggers the blade-changing sequence through its integrated control element.

Inventive Principle:
Principle #25Self-service

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

Enables seamless transition of the blade between storage and working positions, allowing for easy replacement and improved user convenience by ensuring the driver projection is always engaged or disengaged as needed, enhancing the operational efficiency of the knife.

Implementation Method 1

The blade change button 16 is to be actuated against the restoring force of a spring element 20

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a flexible or rigid coupling element that bends or pivots to enable easy blade exchange

Methodology Applied
Scientific EffectFlexing: Elasticity

Data Source

PatentEP3766648B1Safety knife
Publication Date: 2023.08.30 WOLFCRAFT GMBH
  • EP3766648B1 patent drawingFigure 1~2
  • EP3766648B1 patent drawingFigure 3~5
  • EP3766648B1 patent drawingFigure 6~7

AI summary

The invention relates to a knife for receiving a replaceable blade (12), with a housing (1, 2) which has a blade channel (3) for inserting a blade (12) having a drive recess, with a slide (7) which is movable along the housing (1, 2) from the outside of the housing along a path of movement in order to move the blade (12) from a storage position inserted in the blade channel (3) to a working position projecting from an opening of the blade channel (3), which carries a coupling element (4) for coupling the slide (7) with the blade (12) with a drive projection (5) which engages in the drive recess, and with a blade change button (16).For a further development that is advantageous for use, the invention proposes that the blade change button (16) has a blocking section (17) projecting into the path of movement of the slide (7), against which the slide (7) abuts in the final phase of its movement into the working position, and which can be moved out of the path of movement of the slide (7) by actuating the blade change button (16), so that the slide (7) can move the blade (12) beyond the working position into a blade change position, whereby the driver projection (5) is controlled from the driver recess.