Cutting Device for Strip Material with Segmented Blade Geometry

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Solution Overview

Problem

Cutting textile or steel cord strips to achieve a butt splice with high strength is challenging due to exposure of threads during cutting, leading to insufficient splice resistance, as existing knives either scratch the rubber or get tangled with threads.

Innovation Solution

A cutting device using a combination of a rounded blade for initial gating and a hook knife for cutting, ensuring sufficient rubber remains on both edges, with separate vertical mobility and a locking mechanism to prevent offset entry, and optionally a double cutting blade with a rounded and hook-shaped edge for combined functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a hook knife is retracted from above into the strip material, then the achievable splice resistance is highest, but the lower knife tip scratches the rubber and exposes threads, leading to locally low splice resistance

Engineering Contradiction:
Improvesplice resistanceVSAvoidthread exposure and rubber scratching
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The cutting operation is divided into two separate cutting edges on the same knife: a first cutting edge that creates an initial incision, and a second cutting edge that completes the cut. This segmentation allows each edge to perform its specific function without causing thread exposure or rubber scratching that would compromise splice resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first cutting edge performs a preliminary cutting action to create an initial incision in the strip material before the second cutting edge completes the cut. This preliminary action prepares the material in a way that allows the second edge to cut cleanly without exposing threads or scratching the rubber surface.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If a circular blade is used to cut the strip material, then no problems occur during cutting, but the achievable splice resistance decreases compared to hook knife cutting

Engineering Contradiction:
Improvecutting smoothnessVSAvoidsplice resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The knife incorporates two distinct cutting edges with different geometries: a first cutting edge optimized for smooth cutting operations, and a second cutting edge optimized for creating clean cuts that preserve splice resistance. This segmentation combines the advantages of both circular blade smoothness and hook knife cutting quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the knife (the two cutting edges) have different local qualities optimized for different functions. The first cutting edge has properties suited for smooth cutting, while the second cutting edge has properties optimized for creating clean, high-strength cuts. This local differentiation resolves the contradiction between cutting smoothness and splice resistance.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a hook knife enters the strip material from the side where threads end, then threading problems are avoided, but the knife directly enters thread ends causing tangling or thread pull-out

Engineering Contradiction:
Improvethread scratching avoidanceVSAvoidthread tangling and pull-out
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The cutting action is segmented into two stages performed by two different cutting edges. The first cutting edge creates an initial incision that guides the material, while the second cutting edge completes the cut by entering through the already-created opening, thereby avoiding direct contact with thread ends and preventing tangling or pull-out.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If a single knife is used for cutting, then the device structure is simple, but it cannot achieve both optimal gating and high-strength cutting simultaneously

Engineering Contradiction:
Improveknife configuration simplicityVSAvoidsplice resistance and gating quality
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

A single knife is designed with multi-functionality by incorporating two different cutting edges on the same tool. The first cutting edge performs the gating function, while the second cutting edge performs the high-strength cutting function. This multi-functionality allows one knife to accomplish what would otherwise require two separate knives, maintaining structural simplicity while achieving optimal performance.

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

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 approach allows for optimal strip cutting, maintaining high splice strength by ensuring rubber is present on both cut edges, preventing thread exposure and tangling, and enhancing the smear effect for stronger connections.

Implementation Method 1

a first knife (6), which has a rounded, preferably curved cutting edge (49), but can also be designed as a circular circular blade (7)... moves onto the strip material from above, so it enters from above... to produce the gating

Methodology Applied
Scientific EffectCutting:

Implementation Method 2

a second hook knife (18)... retracted in the formed gate from the side... pulled through the strip material, and in the area of the cut carried out with this knife, sufficient rubber also remains on the two cut strip edges

Methodology Applied
Scientific EffectCutting:

Implementation Method 3

a heating device for heating the hook blade and / or the rounded blade or the double cutting blade... the hot hook knife or the hot hook-shaped cutting edge of the double cutting blade easily melts the rubber of the band in the cutting area

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

the hot hook knife or the hot hook-shaped cutting edge of the double cutting blade easily melts the rubber of the band in the cutting area

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 5

the rounded blade is usually mounted slightly displaceable and looking at the slow retraction his way between the threads

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 6

a releasable locking device for the hook knife or double cutting blade... designed for example in the form of two laterally on the hook knife, the double cutting blade or knife holder attacking movable jaws

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Implementation Method 7

corresponding lifting motors or electric, pneumatic or hydraulic cylinders... the entire cutting means consisting of rounded blade and hook knife with the corresponding separate vertical drives

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Implementation Method 8

a common drive device in the cutting direction... the entire cutting means consisting of rounded blade and hook knife with the corresponding separate vertical drives, locking device, etc. are moved together

Methodology Applied
Scientific EffectMechanical transmission: Gear

Data Source

PatentEP1839822B8Cutting device for cutting strip material, in particular textile or steel rope strips
Publication Date: 2009.09.02 FISCHER TIRETECH GERMANY GMBH

AI summary

Machine for cutting textile- or steel cord strip (2) has a cutter (6) with a rounded edge which is used to carry out the first cut and a hooked cutter (18) which cuts the remainder of the strip. Alternatively these may be combined into a double-edged cutter. An independent claim is included for a method for cutting textile- or steel cord strip as described.