Endoscopic Sewing Machine Needle Bar Thread Path Design

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Solution Overview

Problem

Endoscopic sewing machines face issues with thread storage, feeding, and tensioning, leading to excessive thread deflection and radial loads on needle and gripper bars, causing deformations and skipped stitches due to inadequate thread guidance and tension management.

Innovation Solution

Designing the needle bar as a hollow body with a straight thread path from the thread tensioning device to its entry point, minimizing thread friction and deflections, and using a guiding element inside the needle bar to ensure smooth thread guidance, along with a detachable thread supply system for ease of use and sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the thread passes through multiple deflection points to reach the needle from the thread store, then the thread can be fed to the needle, but the radial loads on the needle bar and gripper bar increase significantly causing deformations and skipped stitches

Engineering Contradiction:
Improvethread feedingVSAvoidstitch formation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent repositions the thread store from a conventional location to being integrated with or adjacent to the needle bar assembly, fundamentally changing the spatial dimension of thread delivery. This allows the thread to travel in a straight line from the store through the needle eye, eliminating the need for multiple deflection points and reducing radial loads on the bars.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a thread guide or channel as an intermediary element that directs the thread in a straight path from the thread store to the needle eye. This intermediary structure eliminates the need for the thread to deflect around obstacles, thereby reducing friction and radial forces on the needle and gripper bars.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a conventional thread store and tensioning device are integrated into the endoscopic sewing machine, then thread storage and tensioning are provided, but the device complexity increases significantly making it more susceptible to faults

Engineering Contradiction:
Improvedevice reliabilityVSAvoidthread management system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the thread store, thread guide, and needle bar into a integrated assembly where the thread store is positioned to feed thread directly into the needle bar or needle eye. This consolidation eliminates separate tensioning devices and complex thread routing mechanisms, reducing the number of potential failure points while maintaining thread delivery functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The needle bar assembly is designed to serve multiple functions: it provides structural support for the needle, guides the thread in a straight path, and may incorporate the thread store or its mounting. This multi-functionality reduces the need for separate dedicated components for each function, thereby simplifying the overall device while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2387954B1Endoscopic sewing machine
Publication Date: 2017.08.09 KARL STORZ SE & CO KG
  • EP2387954B1 patent drawingFigure 1~1a
  • EP2387954B1 patent drawingFigure 2
  • EP2387954B1 patent drawingFigure 3~4

AI summary

The endoscopic sewing machine has a housing with a housing upper part for supporting drives for knot forming tools. A needle bar (5) is provided as a hollow body for supporting and guiding thread. The thread guidance elements, such as thread guide, thread clamping unit (8) and a connecting piece (35) are arranged between a thread coil supporting the thread supply and the needle bar.