Rotating Support Bar Conveyor for Wide PCB Reflow Stability

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Solution Overview

Problem

Circuit boards with large widths are susceptible to local sagging and deformation during reflow soldering due to the increased width of the transport device, affecting the yield of the process.

Innovation Solution

A transport device with a first rail device featuring a first guide rail and conveying belt, where support bars can switch between two states to stabilize the circuit board, reducing sagging by adjusting their angle and position relative to the guide rail.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the width of the transport device is increased to accommodate large-width circuit boards, then the circuit board can be transported, but the circuit board is susceptible to local sagging and deformation due to heating

Engineering Contradiction:
Improvewidth of transport deviceVSAvoidcircuit board deformation
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The conveying belt is segmented into multiple support bars that are distributed along the length direction. Each support bar can independently adjust its height to provide localized support to different areas of the circuit board, preventing sagging and deformation in the middle area while accommodating the overall large width of the board.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support bars are designed to be rotatable between a first state (extended upward to support the circuit board) and a second state (retracted downward). This dynamic adjustment allows the transport device to adapt to different circuit board widths and provide support only when needed, preventing deformation during heating while maintaining flexibility in the transport system.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If support bars are added to prevent sagging, then circuit board stability is improved, but the device complexity increases

Engineering Contradiction:
Improvecircuit board stabilityVSAvoidtransport device structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The support bars are equipped with limiting structures that automatically prevent over-rotation, and the chain structure provides self-support during the heating process. The system uses the circuit board's own weight and the heating process conditions to regulate the support bars' operation, reducing the need for complex external control mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The support bars are integrated into the chain structure of the conveying belt, combining the functions of transport and support into a single unified system. The limiting structures are built into the support bars themselves, merging the support function with the structural integrity of the transport device.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If support bars are extended to support the circuit board, then sagging is prevented, but the space occupation increases

Engineering Contradiction:
Improvesagging preventionVSAvoidspace occupation
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The support bars can rotate between an extended position (first state) where they provide support to prevent sagging, and a retracted position (second state) where they minimize space occupation. This dynamic capability allows the same structure to serve both functions at different times during the transport cycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The support bars periodically switch between the first state and second state as they move along the transport device. They are extended to support the circuit board when needed and retracted when not needed, creating a periodic pattern of support and retraction that maintains precision while minimizing overall space requirements.

Inventive Principle:
Principle #19Periodic action

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

The solution effectively prevents sagging and deformation of large circuit boards during reflow soldering by stabilizing the middle area, ensuring consistent processing quality and reducing space occupation.

Implementation Method 1

each of the support bars rotatably connected to the chain, where each of the support bars is rotatable to a first state and a second state

Methodology Applied
Scientific EffectRotational movement:

Data Source

PatentEP4635881A1Transport device and reflow oven comprising transport device
Publication Date: 2025.10.22 ILLINOIS TOOL WORKS INC
  • EP4635881A1 patent drawingFigure 1
  • EP4635881A1 patent drawingFigure 2A~2B
  • EP4635881A1 patent drawingFigure 3A

AI summary

The present disclosure discloses a transport device and a reflow oven comprising the same. The transport device includes a first rail device. The first rail device includes a first guide rail and a first conveying belt. The first conveying belt includes a chain and a plurality of support bars, with the plurality of support bars arranged in a length direction, and each of the support bars rotatably connected to the chain, where each of the support bars is rotatable to a first state and a second state, and a distance from the top of the support bar in the second state to the chain is less than that from the top of the support bar in the first state to the chain. The support bars in the first state can support an element to be processed, and the support bars in the second state do not support the element to be processed, thereby reducing the occupied space. With the arrangement of the rotatable support bars, the first conveying belt of the first rail device can always travel in the length direction, enabling a lifting function of the support bars, without the need to move the position of the first conveying belt.