Cable Knife Blade Guard with Spring-Loaded Safety Slide

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Solution Overview

Problem

Existing cable knives with hooked blades pose a risk of injury due to the movable bearing of the hooked blade, which impairs guidance during cutting and increases the likelihood of the cable sheath slipping off.

Innovation Solution

A blade guard with a safety slide and protective cover that securely holds the hooked blade, using a spring force to automatically return to a secured position when the hooked blade is not in use, minimizing exposure and risk of injury.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the hooked blade is slidably mounted in the housing with a movable bearing, then the hooked blade can be pushed out of the housing when required, but the hooked blade does not have a firm seat on the housing which impairs the guidance of the hooked blade when cutting the cable sheath and increases the risk of injury

Engineering Contradiction:
Improveease of blade deploymentVSAvoidblade guidance stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The hooked blade is pre-fixed to the housing in a reliable manner before use, eliminating the need for movable bearings. The blade is pushed out of the housing when required but maintains a firm seat through fixed mounting with cutting edge clearance, ensuring both ease of deployment and stable guidance during cutting operations.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the hooked blade is pulled back into the housing in the secured position, then there is no danger from the hooked blade when used with other blades on the cable knife, but there is still a risk of injury when making a longitudinal cut with the hooked blade

Engineering Contradiction:
Improveblade exposure riskVSAvoidcutting safety
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A blade guard is introduced as an intermediary protective element between the user and the hooked blade. The blade guard can be moved between a retracted position during cutting operations and a covering position for safety, allowing the blade to remain in place while providing protection when not in use. This eliminates the need to retract the blade itself while maintaining both accessibility and safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the hooked blade is fixed to the housing, then the hooked blade has a firm seat for good guidance when cutting the cable sheath, but the hooked blade protrudes from the housing and poses a risk of injury

Engineering Contradiction:
Improveblade guidance stabilityVSAvoidblade exposure risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The blade system is segmented into the fixed hooked blade mounted to the housing and a separate movable blade guard. The blade remains fixed for stable guidance while the guard can be independently positioned to cover or expose the blade as needed, separating the functions of cutting stability and safety protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade guard serves as an intermediary protective element that can be moved between covering and retracted positions. When covering, it protects the exposed blade; when retracted, it allows the fixed blade to perform cutting operations with stable guidance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The blade guard effectively reduces the risk of injury by ensuring the hooked blade is automatically secured when not in use, preventing accidental exposure and enhancing safety during cable cutting operations.

Implementation Method 1

The spring force for the protective cover is applied via a protective spring arranged in the longitudinal direction of the housing. This ensures that the protective cover is quickly pressed back into the secure position.

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3091622B1Blade guard for a hooked blade of a cable knife
Publication Date: 2020.07.08 KRAMPE IMMOBILIEN
  • EP3091622B1 patent drawingFigure 1~3
  • EP3091622B1 patent drawingFigure 4~7

AI summary

The invention relates to a blade guard for a cable knife with a housing (1) as a handle and a hook blade (4) projecting from an end face of the housing (1), which can be secured by a protective cover, wherein the hook blade (4) is fixedly attached to the housing (1) and the protective cover (5) is held securely over the hook blade (4) in a locking position by means of a locking slide (3) as a latch and is slidable into the housing (1) against a spring force in a working position and, if the protective cover (5) pops out, it automatically returns to the locking position.