Cylindrical Screen Basket End Ring Press-Fit Assembly

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Solution Overview

Problem

Existing cylindrical screening devices face issues with the connection of end rings, which are prone to breaking due to high stress and shrinkage stresses during the welding process, leading to distortion of screen slots and potential blockages, requiring laborious sanding and additional fixation methods.

Innovation Solution

The method involves inserting an outer rod holder into the end ring's recess and applying radial forces to deform the end ring and rod holder, creating a permanent form fit that jams and hardens, eliminating play and enhancing the axial load-bearing capacity, with radial pressing using dies distributed evenly around the circumference to achieve precise fixation without exposing the rods to bending forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding is used to attach end rings to screen baskets, then the attachment strength is improved, but the end rings are prone to breaking due to shrinkage stresses and distortion of screen slots

Engineering Contradiction:
Improveattachment strengthVSAvoidscreen slot precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the welding process with a mechanical interference fit system. Rod holders with external threads engage with internally threaded recesses in end rings, eliminating thermal stresses and distortion associated with welding while maintaining strong attachment. This mechanical connection system avoids shrinkage stresses that cause end ring failure and prevents distortion of screen slots near weld seams.

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

Solution Approach 2:

The patent changes the connection mechanism from thermal (welding) to mechanical (threaded interference fit). The rod holders are designed with external threads that screw into internally threaded recesses in the end rings, creating a secure mechanical connection without the harmful thermal effects of welding. This parameter change eliminates both shrinkage stresses and distortion while maintaining attachment strength.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If welding is used to fix end rings, then attachment is achieved, but laborious sanding and additional fixation methods are required due to distortion and tempering colors

Engineering Contradiction:
Improveattachment processVSAvoidsanding time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces welding with a mechanical threaded connection system that requires no post-weld processing. The rod holders with external threads screw into the end rings, creating an attachment that needs no sanding or tempering color removal, eliminating the time-consuming follow-up operations associated with welding.

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

3Strength

If profile bars are welded to bar holders, then fixation is achieved, but the rods are exposed to bending forces and supporting forces that compromise precision

Engineering Contradiction:
Improvefixation strengthVSAvoidrod position precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces welding with a mechanical interference fit system where rod holders with external threads engage with internally threaded recesses. This mechanical connection avoids exposing the profile bars to bending forces and supporting forces during attachment, maintaining their precise positioning without the distortions caused by welding stresses.

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

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 method simplifies the attachment of end rings, reduces the risk of breakage, maintains precise screen opening dimensions, and eliminates the need for additional fixation methods like welding, ensuring high accuracy and durability of the screening device.

Implementation Method 1

a permanent form fit between the profile rods and the recesses of these outer rod holders is produced via forces acting radially from the outside on the end rings and the outer rod holder

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

forces acting radially from the outside on the end rings and the outer rod holder, a change in shape of the end rings and the outer rod holder and thereby a permanent form fit

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3807019B1Screening production method for a cylindrical screening device and cylindrical screening device
Publication Date: 2022.07.13 VOITH PATENT GMBH
  • EP3807019B1 patent drawingFigure 1~4b

AI summary

The invention relates to a method for producing a cylindrical screening device comprising a plurality of profiled bars (1), in which several mutually spaced, annular bar holders (3,5), which run perpendicular to the cylinder axis (2), are provided on the inner surface with recesses (4) that are open at the edges, the shape of which corresponds substantially in a complementary manner to the bases of the profiled bars (1) and which are slightly larger than the bases and in which the profiled bars (1) are inserted into the recesses (4) in parallel to each other and parallel to the cylinder axis (2). According to the invention, an outer bar holder (5) is in each case positioned in the region of a respective end-sided end ring (6) of the screening device, and the end ring (6) projects radially beyond the bar holder (5). In this case, the attachment of the end rings (6) is simplified by virtue of the fact that the respective outer bar holder (5) is joined into an end-sided recess (7) of the respective end ring (6), wherein, by means of forces acting radially from the outside onto the end rings (6), a change in shape of the end rings (6) and of the outer bar holders (5) as well as a permanent positive connection between the profiled bars (1) and the recesses (4) of said outer bar holders is produced.