Strand Pelletizer Cutting Clearance Adjustment Mechanism

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Solution Overview

Problem

Current strand pelletizers require complex and costly adjustments for precise cutting gap settings, involving manual effort and high susceptibility to inaccuracies due to tolerances and wear, necessitating frequent recalibration and requiring skilled personnel.

Innovation Solution

A mechanical adjustment system where the cutting stick holder is pressed against the cutting rotor by a spring, utilizing a self-locking mechanism to maintain alignment during reverse rotation, allowing for precise gap setting without manual measurement, and optionally incorporating a cutting gap enlarger for specific applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual adjustment with feeler gauges is used, then cutting gap can be set, but adjustment requires great effort and high skill level

Engineering Contradiction:
Improvecutting gap setting accuracyVSAvoidadjustment effort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The cutting bar holder is equipped with a spring mechanism that automatically presses the cutting bar against the cutting rotor, eliminating the need for manual positioning and feeler gauge insertion. The system self-adjusts to maintain optimal cutting gap through the spring's constant pressure.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment process using feeler gauges and hand-operated clamps is replaced by an automated spring-loaded mechanism that continuously maintains the cutting bar in contact with the cutting rotor, reducing adjustment to simple locking/unlocking actions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If cutting bar is held by clamping device with screws, then position can be changed, but cutting gap cannot be precisely set to zero

Engineering Contradiction:
Improvecutting bar adjustabilityVSAvoidcutting gap precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The spring mechanism automatically compensates for tolerances and wear by maintaining constant pressure between the cutting bar and cutting rotor, ensuring the cutting gap is precisely controlled without requiring manual measurement or adjustment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes the state of the cutting bar from a statically clamped position to a dynamically maintained position through spring pressure, allowing the cutting gap to be precisely controlled by the spring force rather than fixed screw clamping.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If eccentrics are used to press cutting bar, then adjustment is facilitated, but cutting strip can be displaced and new adjustment is required

Engineering Contradiction:
Improveadjustment facilitationVSAvoidcutting strip position stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The spring mechanism continuously maintains pressure on the cutting bar, automatically compensating for any displacement or wear that occurs during operation, eliminating the need for repeated adjustments that occur with eccentric mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring provides continuous pressure and adjustment force throughout operation, whereas eccentrics provide intermittent adjustment only during setup. This continuous action maintains stable cutting gap without displacement issues.

Inventive Principle:
Principle #20Continuity of useful action

4Extent of automation

If carriage with linear guide is used, then electromagnetic adjustment is possible, but device complexity increases

Engineering Contradiction:
Improveelectromagnetic adjustment capabilityVSAvoidcarriage and rail guide structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The complex carriage and linear guide system is extracted and replaced by a simple spring-loaded holder that attaches directly to the cutting rotor assembly, retaining the essential adjustment function while eliminating unnecessary mechanical complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a complex guided carriage to position the cutting bar, the invention inverts the approach by using spring pressure to maintain contact, with adjustment achieved through simple locking mechanisms rather than electromagnetic actuators.

Inventive Principle:
Principle #13The other way round (Inversion)

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

Simplifies the adjustment process, reduces personnel requirements, and achieves high accuracy in setting the cutting gap to zero or a desired width, minimizing the need for frequent recalibration and reducing operational complexity.

Implementation Method 1

wherein the cutting stick holder (4) can be pressed against the cutting rotor (2) by the force of at least one spring (43)

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a rotatable cutting rotor (2) with cutting teeth (21) arranged thereon and a cutting bar (3), which is the counterpart to the cutting teeth (21) rotating past it

Methodology Applied
Scientific EffectMechanical cutting: Friction

Data Source

PatentEP2296857B1Strand pelletizer with cutting clearance adjustment and method for adjustment of the cutting clearance
Publication Date: 2011.11.23 IPS INTELLIGENT PELLETIZING SOLUTIONS
  • EP2296857B1 patent drawingFigure 1
  • EP2296857B1 patent drawingFigure 2
  • EP2296857B1 patent drawingFigure 3

AI summary

A strand pelletizer for cutting up material in the form of a strand, comprising a feed mechanism for feeding in the material to be cut up and a rotatable cutting rotor with cutting teeth arranged on it and a cutting bar, which is the counterpart of the cutting teeth rotating past it and is mounted on a cutting bar holder, and a cutting clearance between the cutting bar and a cutting tooth can be adjusted by a movement of the cutting bar holder with respect to the cutting rotor, wherein the cutting clearance can be reduced to zero by it being possible after releasing an arresting device for the cutting bar holder to be pressed against the cutting rotor by the force of at least one spring and for a self-locking means to be pressed against the cutting bar holder, thereby inhibiting the cutting bar holder from being moved by the force of the spring but still allowing freedom of movement under the forces of the cutting teeth when the cutting rotor rotates counter to its operating direction, and the self-locking means can be released from the cutting bar holder.