Carding Drum Shell With Tapered Wall Thickness

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Solution Overview

Problem

High-speed carding drums experience uneven elastic deformations due to centrifugal forces, leading to variations in the carding gap and potential damage, which existing solutions address at the expense of high material costs or complex constructions.

Innovation Solution

A card drum with a thick, cylindrical shell and radially arranged spokes, where the wall thickness is greater at the connection areas and continuously reduced between them, with a specific tapering angle to distribute centrifugal forces uniformly, allowing for high-speed operation without irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotational speed of the carding drum is increased to achieve high production volumes, then productivity is improved, but uneven elastic deformations occur in the drum due to centrifugal forces, leading to carding gap variations and potential damage

Engineering Contradiction:
Improveproduction volumeVSAvoiddrum shape stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The drum shell is designed with non-uniform wall thickness, featuring thicker regions at spoke connection areas and progressively thinner regions between spokes. This local variation in structural properties allows the drum to better distribute and withstand centrifugal forces during high-speed rotation, maintaining shape stability while enabling increased productivity

Inventive Principle:
Principle #3Local quality

2Strength

If the wall thickness of the drum shell is increased uniformly to improve strength and reduce deformations, then shape stability is improved, but the mass of the drum increases, leading to higher centrifugal forces and material cost increases

Engineering Contradiction:
Improvedrum shell strengthVSAvoiddrum mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

Instead of uniform wall thickness, the invention implements localized thickness variations where material is concentrated at spoke connection areas (which experience highest stresses) and reduced between spokes. This optimizes strength distribution while minimizing overall mass and centrifugal forces

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The drum shell is pre-formed with the specific non-uniform thickness profile during manufacturing, anticipating and compensating for centrifugal forces before operation. The thicker regions at spoke connections are built in advance to counteract the expected deformation patterns during high-speed rotation

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If complex reinforcement structures such as internal ribs or cell divisions are added to improve shape retention, then drum stability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedrum shape retentionVSAvoiddrum construction complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention achieves shape retention through local variation in wall thickness rather than adding complex internal reinforcement structures. The non-uniform thickness profile alone is sufficient to distribute centrifugal forces evenly, avoiding the need for additional ribs, cells, or other complex features

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention extracts and eliminates unnecessary complex internal reinforcement structures from the drum design. By relying on the optimized wall thickness distribution alone, the design removes redundant elements that would increase manufacturing complexity and cost while achieving the same or better shape stability

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the drum's strength and stability, enabling high-speed operation without unwanted deformations, maintaining a consistent carding gap and reducing material costs and complexity.

Implementation Method 1

Increasing the rotational speeds increases the centrifugal forces on the drum of the carding machine (carding drum), which cause uneven elastic deformations in the diameter range of the drum of the carding machine due to the resulting uneven stresses.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3631059B1Drum for a carding machine
Publication Date: 2022.12.21 MASCHINENFABRIK RIETER AG
  • EP3631059B1 patent drawingFigure 1~2
  • EP3631059B1 patent drawingFigure 3~4

AI summary

The invention relates to a drum (5) for a carding machine (1) comprising a cylindrical drum casing (M) which has a wall thickness (a, d1, d2) and which is connected in the interior (IR) to at least two spokes (S1, S2, S3, S4) extending in the radial direction which, as viewed in the axial direction of the drum (5), are arranged at a distance (b) from one another. In order to minimise changes in the diameter range of the drum casing at high centrifugal forces, according to the invention the wall thickness of the drum casing (M) in the region of the connection (V1, V2) to each spoke (S3, S4) is greater in value (d1) than the wall thickness outside this connection region (V1, V2), wherein the wall thickness (d1) of the drum casing - as viewed in the axial direction of the drum - at least in the region between the spokes (S3, S4) - starting from the connection region of each spoke - is continuously reduced to a minimum wall thickness (d2).