Spiral Pipe Forming Without Inner Periphery Restriction

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Solution Overview

Problem

Existing pipe-forming apparatuses for spiral pipes have structural enlargement and weight increase due to inner periphery restriction bodies, which can inhibit water flow and are not suitable for non-circular pipe cross sections, and they often result in diameter reduction of the spiral pipe during formation.

Innovation Solution

A pipe-forming apparatus that omits the inner periphery restriction body, using a pipe end release-type mechanism where the driving part presses the strip portion from the inner periphery to fit with the preceding spiral pipe portion, and a guide portion engages from the outer periphery to stabilize the apparatus and ensure smooth propulsion, allowing for non-circular pipe formation without structural enlargement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an inner periphery restriction body is provided inside the preceding spiral pipe portion, then the cross section of the spiral pipe is restricted and maintained, but the apparatus structure becomes enlarged and heavier, and water flow is inhibited

Engineering Contradiction:
Improvecross section restrictionVSAvoidapparatus structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention removes the inner periphery restriction body from the apparatus, extracting the problematic component that caused structural enlargement and water flow inhibition. Instead, it uses the outer periphery restriction body and driving part configuration to achieve the necessary cross section control without internal restrictions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention inverts the approach by placing the restriction body on the outer periphery rather than the inner periphery. The outer periphery restriction body restricts the spiral pipe from the outside, eliminating the need for inner periphery restriction and thereby avoiding water flow inhibition while maintaining cross section control.

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

2Manufacturing precision

If an inner periphery restriction body is provided, then the spiral pipe cross section is maintained, but the apparatus weight increases

Engineering Contradiction:
Improvecross section maintenanceVSAvoidapparatus weight
Core Design Contradiction:
Manufacturing precisionVSWeight of moving object

Solution Approach 1:

The invention extracts and removes the inner periphery restriction body that added unnecessary weight. The cross section maintenance function is achieved through the outer periphery restriction body and driving part configuration instead, reducing overall apparatus weight.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If an inner periphery restriction body is provided, then the spiral pipe shape is controlled, but water flow inhibition occurs

Engineering Contradiction:
Improveshape controlVSAvoidwater flow inhibition
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention inverts the restriction approach from inner periphery to outer periphery. The outer periphery restriction body controls the spiral pipe shape from the outside, eliminating internal obstructions that caused water flow inhibition while maintaining effective shape control.

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

4Strength

If the strip member is pressed toward the fitting position, then the fitting portion joins, but the apparatus requires complex tension management

Engineering Contradiction:
Improvefitting joint strengthVSAvoidtension management
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention inverts the pressing direction approach by using the driving part to press the following strip portion from the inner periphery toward the fitting position, utilizing the natural tension in the strip member rather than requiring complex external tension management systems.

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

Data Source

PatentEP3812128B1Pipe-forming apparatus for spiral pipe and pipe-forming method thereof
Publication Date: 2024.01.31 SEKISUI CHEMICAL CO LTD
  • EP3812128B1 patent drawingFigure 1(a)~1(b)
  • EP3812128B1 patent drawingFigure 2
  • EP3812128B1 patent drawingFigure 3

AI summary

Provided is a pipe-forming apparatus with which a spiral pipe can be formed using a simple configuration. A driving part 10 of a pipe end release-type pipe-forming apparatus 3 having a non-inner periphery restriction structure presses a following strip portion 92 toward a pipe end portion 91e of a preceding spiral pipe portion 91 obliquely with respect to a machine-height direction HD. A pipe end guide 20 is constrained in a machine-width direction WD with respect to the pipe end portion 91e, and slidably engaged in a propelling longitudinal direction LD. The pipe end guide 20 includes a flat-shaped receiving portion 21a,22a along the propelling longitudinal direction LD. The receiving portion 21a,22a configures to receive the pipe end portion (91e) from the reverse side. A pressing force for the following strip portion 92 provides a fitting force between the following strip portion 92 and the pipe end portion 91e, and a propelling force for forward propulsion.