Modular Wearable Injector Drive Train With Tool-Free Assembly

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Solution Overview

Problem

Existing wearable injectors have complex and costly drive trains that are difficult to assemble and maintain, contributing to high manufacturing costs and requiring complex quality control procedures.

Innovation Solution

A modular drive train assembly for wearable injectors, comprising a chassis, telescoping driving assembly, and actuator, constructed from polymeric components, which allows for easy assembly and replacement of faulty parts without tools, utilizing a telescoping mechanism with elastically expandable collars and bearings for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional drive train components and assembly methods are used, then operational reliability is maintained, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drive train is divided into modular components including a motor module, transmission module, and telescoping assembly module. Each module can be independently manufactured, tested, and replaced. The telescoping assembly itself is segmented into multiple shafts (first shaft, second shaft, third shaft) that can move independently, allowing the system to achieve complex motion from simpler individual components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested telescoping structure where the second shaft is received within the first shaft, and the third shaft is received within the second shaft. This nested arrangement allows multiple functional elements to be compactly integrated while maintaining independent movement capabilities, reducing overall device complexity without sacrificing operational reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If complex quality control procedures are implemented, then manufacturing quality is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemanufacturing qualityVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By segmenting the drive train into standardized modular components, each module can be manufactured using consistent processes and subjected to uniform quality control procedures. This modularity simplifies the manufacturing quality management system compared to controlling each individual component separately, reducing overall manufacturing costs while maintaining high manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs interference fits and elastic deformation parameters in the connection mechanisms (such as the interference fit between shafts and housing, and the elastic collar engagement). These parameter-based design choices enable tool-free assembly and self-aligning connections, reducing the need for complex quality control procedures while ensuring consistent manufacturing quality.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If telescoping assembly components are made compact, then device size is reduced, but assembly and maintenance difficulty increases

Engineering Contradiction:
Improvedevice sizeVSAvoidassembly and maintenance difficulty
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The nested telescoping structure allows the drive train to achieve a compact form factor when in the retracted state, while the modular design of each nested shaft and module enables easy disassembly and maintenance. Each module can be independently accessed and replaced without disassembling the entire compact structure, resolving the contradiction between compact size and ease of maintenance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent enables individual modules and shafts to be extracted from the compact telescoping assembly without requiring complete disassembly. The motor module can be removed from the housing, and individual shafts can be extracted from their respective bores, allowing for easy maintenance and replacement while maintaining the compact nested structure during normal operation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If polymeric components are used, then manufacturing cost is reduced, but structural strength may be compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoidstructural strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent utilizes polymeric materials for the housing and various structural components, taking advantage of their cost-effectiveness and ease of manufacturing through injection molding. The design incorporates reinforcement features such as ribs, thickened walls, and interference fit connections that compensate for the inherently lower strength of polymeric materials compared to metals, achieving the necessary structural strength while maintaining low manufacturing costs.

Inventive Principle:
Principle #40Composite materials

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 modular design reduces assembly complexity, lowers manufacturing costs, and facilitates easy maintenance by allowing tool-free assembly and replacement of components, while maintaining operational efficiency.

Implementation Method 1

the collar is configured to elastically snap over an interference element of the bearing, whereby engagement of the collar with the bearing axially secures the first shaft to the chassis

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3630226B1Modular drive train for wearable injector
Publication Date: 2025.10.22 WEST PHARM SERVICES IL LTD
  • EP3630226B1 patent drawingFigure 1
  • EP3630226B1 patent drawingFigure 2
  • EP3630226B1 patent drawingFigure 3

AI summary

A modular drive train is selectively securable within a wearable injector. The drive train includes a chassis and a telescoping driving assembly mounted within the chassis. The driving assembly includes a first shaft rotatable relative to the chassis, and a second shaft connected with the first shaft and axially movable relative thereto. Rotation of the first shaft axially drives the second shaft. The chassis includes one of a bearing and an elastically expandable collar projecting axially forward into the chassis from a rear end thereof, and the first shaft includes the other of the bearing and the elastically expandable collar projecting axially rearwardly from a rear end thereof. The collar is configured to elastically snap over an interference element of the bearing, whereby engagement of the collar with the bearing axially secures the first shaft to the chassis and permits rotation of the first shaft about the bearing.