Extrusion Grid Comb Segmentation for Girder Wire Positioning

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Solution Overview

Problem

The existing manufacturing process for prestressed concrete beams by spinning often results in curved beams due to inadequate lateral positioning of prestressing wires, leading to a high rate of scrap products.

Innovation Solution

A separate fixed comb for guiding prestressing wires and a movable comb for retaining concrete are introduced, with the guide teeth being rigidly secured to the grid and the retaining teeth having multiple points for precise vertical insertion and retention, ensuring accurate positioning of the wires and concrete.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a movable comb is used to retain concrete and guide prestressing wires, then the device can be simplified and operated more easily, but the lateral positioning precision of prestressing wires deteriorates leading to curved beams

Engineering Contradiction:
Improveease of operationVSAvoidlateral positioning precision of prestressing wires
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The comb is divided into two distinct parts: a fixed comb rigidly secured to the grid for guiding prestressing wires with precise lateral positioning, and a movable comb that can be adjusted longitudinally for retaining concrete. This segmentation allows each part to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixed comb acts as an intermediary element between the grid and the prestressing wires, providing a stable reference structure that ensures accurate lateral positioning of the wires while allowing the movable comb to perform its concrete retention function independently.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the comb is made movable to allow concrete pouring, then the ease of operation improves, but the reliability of wire positioning deteriorates causing beams to curve

Engineering Contradiction:
Improveease of operationVSAvoidreliability of wire positioning
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The comb structure is segmented into a fixed portion rigidly attached to the grid for reliable wire guidance and a movable portion for flexible concrete retention, allowing each segment to fulfill its specific function optimally.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a fully movable comb to a hybrid structure where the fixed comb provides stable, reliable positioning for prestressing wires, while the movable comb offers dynamic adjustment capability for concrete pouring operations.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If a single movable comb is used for both concrete retention and wire guidance, then the device complexity is reduced, but the manufacturing precision of beam positioning deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidbeam positioning precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The comb function is segmented into two independent systems: a fixed comb with teeth for precise wire guidance and beam positioning, and a movable comb for concrete retention, eliminating the compromise between simplicity and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the comb structure have different properties: the fixed comb has rigid, precise geometry for guidance, while the movable comb has flexible, adjustable characteristics for retention, with each part optimized for its specific local function.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2671698B1Bench for manufacturing girders by extrusion
Publication Date: 2015.12.23 KP1
  • EP2671698B1 patent drawingFigure 1~3

AI summary

The installation has a grid (1) including a series of longitudinal sections (2) that is spaced from/to each other in a lateral manner. The longitudinal sections are rigidly attached to each other. A prestressed cable (7) is intended to be placed between the longitudinal sections. A set of guiding teeth (16) is rigidly attached with the grid. The teeth are attached to each other by a main cross-piece (14). A comb (8) is movable in translation longitudinally with regard to the sections without interfering the cable.