Multilayer Cylindrical Rod Splicing for Dimensional Tolerance

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Solution Overview

Problem

Existing machines and methods are unable to produce pieces of a multilayer, cylindrical tubular rod that meet stringent dimensional and shape tolerances, particularly for the internal diameter, due to errors in layer positioning and phase displacements during the manufacturing process.

Innovation Solution

A method and machine for making pieces of a multilayer, cylindrical tubular rod that involves wrapping a continuous, multilayer web around a feed direction to form a rod, with at least one end-to-end splice, to reduce shape and size irregularities and ensure compliance with specified tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If prior art machines use conventional tube making methods with multiple strips and joints, then the manufacturing process is simpler, but the dimensional precision and shape tolerances cannot meet stringent requirements

Engineering Contradiction:
Improveinternal diameter toleranceVSAvoidmachine structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the tube making process into distinct segments: a forming section where the tube is created with precise dimensional control, and separate splicing sections for joining tube ends. This segmentation allows each section to be optimized for its specific function, with the forming section focusing on precision and the splicing sections on connectivity, thereby achieving stringent dimensional tolerances without requiring the entire machine to be overly complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary splicing mechanism that acts as a mediator between tube production and assembly. This splicing device with clamping jaws and positioning features serves as a buffer that maintains dimensional precision while enabling the joining of tube sections, resolving the contradiction between precision requirements and the need for a complete manufacturing system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If prior art methods use butt joints or lapped joints with adhesive, then the manufacturing process is simpler, but the reliability of closure and positioning is insufficient

Engineering Contradiction:
Improveclosure reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs curved or rounded splicing surfaces and clamping jaws that conform to the cylindrical geometry of the tube. This curvature-based design ensures uniform distribution of clamping forces around the tube perimeter, creating reliable closure without requiring complex adhesive application systems or intricate joint structures, thus maintaining ease of manufacture while improving reliability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The splicing mechanism creates a precise copy or replica of the tube's cylindrical geometry through molded splicing surfaces and form-fitting clamping jaws. This copying approach ensures that the joint geometry exactly matches the required specifications, guaranteeing reliable closure and positioning without needing complex adjustment mechanisms or multiple manufacturing steps.

Inventive Principle:
Principle #26Copying

3Productivity

If continuous webs are fed through multiple process stations, then productivity is higher, but phase displacements and positioning errors occur

Engineering Contradiction:
Improveproduction rateVSAvoidlayer positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent incorporates feedback mechanisms in the form of positioning sensors and adjustable positioning features that continuously monitor and correct the position of tube sections during the splicing process. This feedback system allows the high-speed continuous production to maintain precise layer positioning by detecting and compensating for any phase displacements that occur during rapid feeding through multiple process stations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements preliminary positioning actions before the actual splicing operation. Tube sections are pre-positioned using positioning features and clamping jaws that establish correct alignment in advance of the joining process. This preliminary action ensures that even at high production speeds, the layers are correctly positioned before bonding occurs, preventing phase displacements while maintaining high productivity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3407742B1Method and machine for making pieces of a multilayer, cylindrical tubular rod used to make substantially cylindrical smokers' articles, and the pieces made by the method and machine
Publication Date: 2025.06.04 GD SPA
  • EP3407742B1 patent drawingFigure 1a~1c
  • EP3407742B1 patent drawingFigure 2a~2c
  • EP3407742B1 patent drawingFigure 3a~3c

AI summary

A machine (100) for making pieces of a multilayer, cylindrical tubular rod (1) suitable for making substantially cylindrical smokers' articles comprises first means (101) for feeding at least a first continuous web (102), second means (103) for feeding a second continuous web (104), means (107) for forming a continuous, multilayer web (M) by superposing at least a first layer (2) and a second layer (5) and means (108) for feeding the continuous, multilayer web along a feed direction (X). Also provided are means (110) for forming the rod (1) around the feed direction (X) and means (111) for cutting the rod (1) into pieces. The machine (100) is configured to dispose the lateral edges (4, 7) of at least one between the first and the second layer (2, 5) in such a way as to make at least one end-to-end splice (3, 6). The machine (100) implements a method for making pieces of a multilayer, cylindrical tubular rod (1).