Ultrasonic Welding of IUS Removal Threads Without Knot Bulk

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Solution Overview

Problem

Existing methods for attaching removal threads to intrauterine systems (IUS) often require knotting, which increases the cross-sectional dimensions and can cause mechanical irritation, making them unsuitable for smaller diameter inserters and potentially uncomfortable for patients.

Innovation Solution

An apparatus and method using ultrasonic welding with a welding jig and sonotrode, featuring concave shapes and specific dimensions, to securely attach removal threads without increasing the IUS diameter, ensuring a smooth and reliable attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If knotting is used to attach removal threads to IUS, then the attachment is secure, but the cross-sectional dimensions increase

Engineering Contradiction:

Improveattachment reliabilityVSAvoidIUS cross-sectional dimension

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical knotting system with an ultrasonic welding system. The ultrasonic welding apparatus uses high-frequency vibrations to melt and fuse the threads to the IUS body, eliminating the need for knots. This substitution reduces the cross-sectional dimension while maintaining secure attachment, as the welded joint is more compact than a knotted structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the attachment method from mechanical (knotting) to thermal (ultrasonic welding). By controlling parameters such as welding time, amplitude, and pressure, the process creates a strong bond without adding significant volume. The welding parameters are optimized to achieve reliable attachment while minimizing the increase in cross-sectional dimensions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If knotting is used to attach removal threads, then the threads are secured, but mechanical irritation of uterine tissue occurs

Engineering Contradiction:

Improvethread attachment securityVSAvoidmechanical irritation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical knotting system with ultrasonic welding, which uses high-frequency vibrations and heat to create the bond. This eliminates the sharp edges and irregular surfaces characteristic of knots, resulting in a smoother attachment that reduces mechanical irritation to the uterine tissue while maintaining secure thread attachment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If traditional attachment methods are used, then the process is simple, but the attachment speed is slow

Engineering Contradiction:

Improveprocess simplicityVSAvoidattachment speed

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces manual or mechanical knotting with automated ultrasonic welding. The ultrasonic welding process can be easily automated and controlled by computer programs, allowing for rapid attachment of threads to the IUS. This significantly increases production speed while maintaining process simplicity through automated control systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If larger diameter IUS are used to accommodate knotting, then threads can be attached securely, but patient comfort decreases

Engineering Contradiction:

Improvethread attachment strengthVSAvoidpatient comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces knotting with ultrasonic welding, enabling secure thread attachment on smaller diameter IUS. The welding process creates a strong bond without requiring the additional space needed for knots, allowing the use of smaller IUS that are more comfortable for patients during insertion and use.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 ultrasonic welding method provides a faster, more reliable, and less irritating attachment, reducing the risk of thread jamming and detachment, while being easier to automate and resulting in a strong, homogenous weld.

Implementation Method 1

Ultrasonic welding is a known technique as such, and it is used in many industrial applications. It is based on high-frequency ultrasonic acoustic vibrations that are applied locally to items being held together under pressure to create a solid-state weld.

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

It is based on high-frequency ultrasonic acoustic vibrations that are applied locally to items being held together under pressure to create a solid-state weld.

Methodology Applied

Scientific EffectFriction heating: Viscous Heating

Data Source

PatentUS12515413B2Ultrasound thread welding

Publication Date: 2026.01.06 BAYER OY

AI summary

According to an aspect of the present invention, there is provided an apparatus for ultrasonic welding of a removal thread (1) of an intrauterine system (2). The apparatus comprises a welding jig (3) comprising a welding groove (4), the welding groove having a length Lg, a width Wg and a depth Dg and a bottom (5) with concave shape. The apparatus further comprises a sonotrode (6) having a length Ls that is 150-220% of Lg, a width Ws of a welding tip (7) of the sonotrode that is 80-98% of Wg and a depth Ds. Further, the welding tip of the sonotrode has a concave shape.