Utility Knife Cam Mechanism for Secure Blade Storage

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Solution Overview

Problem

Existing utility knives lack a convenient and secure mechanism for switching between blade positions and storing spare blades, which can lead to user inconvenience and potential safety hazards.

Innovation Solution

The utility knife design includes a handle with a cam surface and a blade holder that is pivotal between extended and folded positions, along with a spare blade holder that engages the handle's cam surface to facilitate smooth operation and secure blade storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the blade holder is made pivotal between extended and folded positions, then the ease of operation is improved, but the reliability deteriorates due to potential accidental blade exposure

Engineering Contradiction:

Improveease of blade position switchingVSAvoidsafety against accidental blade exposure

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The blade holder is designed to be pivotal between extended and folded positions, allowing dynamic adjustment of the blade state. This dynamic mechanism enables easy switching between operational and stored positions, resolving the contradiction by providing operational flexibility while maintaining safety through controlled movement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A cam surface mechanism acts as an intermediary between the blade holder and the handle. The cam surface engages with the blade holder to control its movement, providing a reliable intermediate step that ensures the blade holder moves predictably and safely between positions, preventing accidental exposure while maintaining ease of operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a spare blade holder is added to the utility knife, then the adaptability is improved, but the device complexity increases

Engineering Contradiction:

Improvecapacity for storing spare bladesVSAvoidnumber of blade holder components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spare blade holder is nested within the handle structure, utilizing the existing handle volume to accommodate the additional component. This nesting approach allows the utility knife to store spare blades without significantly increasing external dimensions or overall complexity, as the spare blade holder integrates into the existing handle geometry.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The handle structure serves multiple functions: it houses the primary blade holder, accommodates the spare blade holder, and provides the cam surface mechanism for blade position control. This multi-functionality reduces the need for separate dedicated components, thereby increasing adaptability while minimizing the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If the cam surface mechanism is used to control blade holder movement, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:

Improvesmoothness of blade holder pivotingVSAvoidnumber of cam surface components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The cam surface mechanism is designed to automatically control the blade holder's movement without requiring additional actuators or complex control systems. The cam surface itself performs the function of guiding and controlling the pivotal motion, making the system self-regulating and reducing the need for extra components, thus improving ease of operation while minimizing complexity increase.

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

This design allows for easy and secure switching between blade positions, enhances user safety by preventing accidental blade exposure, and provides a convenient mechanism for storing spare blades.

Implementation Method 1

The spare blade holder further including a cam surface and the cam surface of the spare blade holder engages the cam surface of the handle when the spare blade holder is in the closed position to urge the spare blade holder in a direction from the first longitudinal side of the handle toward the second longitudinal side of the handle

Methodology Applied

Scientific EffectCam mechanism: Cam

Implementation Method 2

The biasing member that biases the actuator toward the locked position

Methodology Applied

Scientific EffectSpring biasing: Spring

Data Source

PatentUS20250073933A1Utility Knife

Publication Date: 2025.03.06 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A utility knife including a handle, a blade, a first blade holder, and a spare blade holder. The spare blade holder is pivotal with respect to the handle between an open position where the recess is exposed to allow a spare blade to be removed from the spare blade holder and a closed position where the recess is within a slot of the handle to inhibit removal of the spare blade from the spare blade holder. The spare blade holder further including a cam surface and the cam surface of the spare blade holder engages a cam surface of the handle when the spare blade holder is in the closed position to urge the spare blade holder in a direction from a first longitudinal side of the handle toward a second longitudinal side of the handle to allow the first blade holder to pivot between extended and folded positions.