Injection-Molded Multi-Part Front Stop for Sheet Alignment

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Solution Overview

Problem

Existing stop devices for sheet-processing machines, particularly in printing presses, are cumbersome to manufacture, assemble, and maintain due to their complex machining processes and high deadweight, necessitating precise alignment and drilling, which complicates replacement and increases operational costs.

Innovation Solution

A multi-part, injection-molded front stop device with a foldable design that allows easy alignment and tool-free assembly, featuring a hinge mechanism for precise positioning on a centering device, enabling quick replacement without disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a front stop is manufactured as a machined cast part, then it achieves sufficient strength and precision, but the manufacturing process becomes complicated and time-consuming

Engineering Contradiction:
Improvealignment precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The front stop is divided into multiple parts: a cast base part and a separately manufactured stop element. The stop element can be produced using injection molding or other efficient processes, then attached to the base part. This segmentation allows each component to be optimized independently, reducing overall manufacturing complexity while maintaining precision through specialized production methods for each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stop element is designed as a replaceable, cost-effective component that can be easily manufactured and replaced when worn or damaged. Rather than machining a permanent cast part, the invention uses a more economical, quickly replaceable element that achieves the same functional requirements with lower manufacturing cost and complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If a front stop is precisely aligned and calibrated during assembly, then it achieves accurate sheet alignment, but the assembly process becomes complicated and time-consuming

Engineering Contradiction:
Improvealignment accuracyVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The stop element is pre-manufactured with precise dimensions and attachment features that ensure correct positioning. Centering devices or locating features are built into the design beforehand, eliminating the need for complex alignment operations during assembly. The component arrives ready-to-install with its alignment characteristics already established during manufacturing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The front stop design incorporates self-aligning features such as centering devices, locating pins, or geometric constraints that automatically position the stop element correctly during installation. The assembly process becomes self-guiding, where the component's own geometry ensures proper alignment without requiring external measurement or adjustment tools.

Inventive Principle:
Principle #25Self-service

3Reliability

If a front stop is drilled and pinned for secure attachment, then it achieves reliable fixation, but replacement requires disassembly and becomes difficult

Engineering Contradiction:
Improvefixation reliabilityVSAvoidreplacement ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The front stop is designed as separable components that can be quickly detached and reattached. Rather than permanent drilling and pinning, the invention uses mechanical attachment methods such as clampable connections, bayonet mounts, or tool-free fastening systems that allow the stop element to be separated from the base part for replacement or maintenance, then securely reattached without damaging the components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment mechanism transitions from a static, permanent connection to a dynamic, reversible connection. The front stop incorporates features that allow it to be securely fixed during operation but easily released when needed, such as quick-release latches, snap-fit mechanisms, or adjustable clamps that provide reliable fixation during use but enable rapid replacement during maintenance.

Inventive Principle:
Principle #15Dynamics

4Stability of the object's composition

If a front stop has high deadweight, then it achieves stability, but it becomes disadvantageous for increasing cycle speeds of printing presses

Engineering Contradiction:
Improvestop stabilityVSAvoidcycle speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The front stop employs composite construction combining materials with different properties. The base part may use dense, stable materials for structural integrity, while the stop element uses lighter materials such as molded plastics or aluminum alloys that provide sufficient functionality with reduced weight. This composite approach maintains the necessary stability for sheet handling while reducing inertial effects that limit cycle speeds.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical parameters of the front stop, particularly its mass and density characteristics. By using lighter materials and optimized geometries, the stop element achieves the required functional performance with significantly reduced weight, allowing the printing press to operate at higher cycle speeds without compromising the stopping accuracy or sheet alignment performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4631899A1Deliverer of a sheet processing machine with a stop device and method for producing and/or assembling a front stop
Publication Date: 2025.10.15 KOENIG & BAUER AG
  • EP4631899A1 patent drawingFigure 1
  • EP4631899A1 patent drawingFigure 2
  • EP4631899A1 patent drawingFigure 3

AI summary

The invention relates to a delivery of a sheet-processing machine, in particular a printing press or punching machine, comprising a stop device with at least one front stop (16) that can be assigned to a front stop cross member (17). The front stop (16) comprises several articulated and/or connected parts (18, 19) for fixing to the front stop cross member (17). The invention also relates to a method for producing and/or assembling a front stop (16).