Cold Pilger Feed Slides With Opposed Collets for Uniform Wall Thickness

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Solution Overview

Problem

Existing cold pilger rolling mills face challenges in achieving homogeneous processing over large feed lengths, particularly due to the geometric limitations and frictional engagement issues between collet chucks, leading to jumps in pipe wall measurements during clamping slide transitions.

Innovation Solution

The rolling mill design features collet chucks with opposite orientations to minimize the distance between frictional engagement areas, utilizing a spindle and spindle nut drive system with a hollow shaft motor for precise control, and optional configurations such as symmetrical or one-sided drives to optimize force application and movement control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If collet chucks are arranged with same orientation in conventional feed gear, then the structure is simpler and easier to manufacture, but the minimum distance between contact points on the workpiece becomes large, causing jumps in pipe wall measurements during clamping slide transitions

Engineering Contradiction:
Improvehomogeneity of processingVSAvoidcollet orientation arrangement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies inversion by orienting the collet chucks in opposite directions rather than the conventional same orientation. This reversal of the standard arrangement allows the frictional engagement areas to be positioned closer together on the workpiece, minimizing the distance between contact points and eliminating measurement jumps during transitions.

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

2Manufacturing precision

If the distance between tendon attack points on the workpiece is large, then the clamping carriages can be positioned further apart, but this causes jumps in pipe wall measurements due to elasticity during transitions

Engineering Contradiction:
Improvepipe wall measurement consistencyVSAvoiddistance between tendon attack points
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent employs asymmetry in the positioning of the collet chucks and their frictional engagement areas. By creating an asymmetric arrangement where the contact points are minimized in distance through opposite orientation, the system achieves more consistent pipe wall measurements during the transition between clamping slides.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If conventional clamping slides are used with same orientation collets, then the feed gear structure is more straightforward, but frictional engagement issues cause jumps during clamping slide transitions

Engineering Contradiction:
Improvesmooth transition between clamping slidesVSAvoidcollet orientation configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies inversion by orienting the collet chucks in opposite directions rather than the conventional same orientation. This reversal of the standard arrangement allows the frictional engagement areas to be positioned closer together on the workpiece, minimizing the distance between contact points and eliminating measurement jumps during transitions.

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

This design reduces the minimum distance between tendon attacks on the workpiece, minimizing the jump caused by elasticity during transitions and ensuring homogeneous feed load across varying blank lengths, enhancing processing efficiency and accuracy.

Implementation Method 1

a hollow shaft motor enclosing the spindle

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

Driven by at least one spindle and a spindle nut, preferably arranged on the clamping slide

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 3

the area of force-locking engagement located closer to one of the ends of the tendon

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3831503B1Rolling system for cold pilgering
Publication Date: 2024.04.03 SMS GROUP GMBH
  • EP3831503B1 patent drawingFigure 1~2
  • EP3831503B1 patent drawingFigure 3~4
  • EP3831503B1 patent drawingFigure 5~6

AI summary

The invention relates to a cold pilger rolling mill comprising a rolling stand (1) for rolling a bloom by means of cold pilgering, and a feeding device (2), wherein the bloom is moved through the rolling stand (1) by means of the feeding device (2) during the rolling process, wherein at least a first clamping element (3) of a first driven clamping slide (4) and at least a second clamping element (5) of a second driven clamping slide (6) are alternately fixed to the bloom, so that the bloom is first moved by a stroke (H1) of the first clamping slide (4) and subsequently by a stroke (H2) of the second clamping slide (6), wherein the first clamping element (3) is oriented opposite to the second clamping element (5).