Drug Delivery Switch Assembly Axial Ratchet

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Solution Overview

Problem

Existing drug delivery devices with electronic systems face challenges in efficient assembly and reliable activation/deactivation of functions, particularly in self-contained devices without a connector for an electrical power source, which affects power management and production costs.

Innovation Solution

A switch assembly for drug delivery devices comprising a chassis, a ring with an annular ratchet profile, and elastically deformable arms, allowing for efficient assembly and reliable switching by mounting components from a single direction, with a lever and spring elements to manage electrical connections during dose setting and delivery operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a connector for external power source is added to provide electrical power, then power availability is improved, but device complexity and loss of substance increase

Engineering Contradiction:
Improvepower availabilityVSAvoiddevice complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent extracts the power source from external connection and integrates it into the device itself through energy harvesting mechanisms. The implantable device contains internal components that generate and store energy, eliminating the need for external power connectors while maintaining continuous power availability for operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The device serves itself by incorporating self-powered mechanisms including energy harvesting from body movements, thermal gradients, or biochemical reactions. The harvested energy is stored in onboard energy storage elements, enabling the device to operate autonomously without external power sources or connectors.

Inventive Principle:
Principle #25Self-service

2Reliability

If more component parts are used for reliable switching, then switching reliability is improved, but assembly complexity and manufacturing cost increase

Engineering Contradiction:
Improveswitching reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple switching functions into integrated circuits and multi-functional components. The electronic system uses microcontrollers and integrated switch arrays that perform multiple switching operations simultaneously, reducing the total number of discrete components while maintaining reliable switching for various device functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The switching system is designed with universal components that can handle multiple functions. A single integrated switching matrix controls power distribution, signal routing, and sensor activation across different device modules, eliminating the need for separate dedicated switches for each function and simplifying assembly.

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

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 enhances assembly efficiency and reliability of electronic functions in drug delivery devices, reducing component parts and maintaining low power consumption states to conserve battery life.

Implementation Method 1

a first electrically conductive and elastically deformable arm and a second electrically conductive and elastically deformable arm

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4208221B1Electronic system for a drug delivery device and drug delivery device
Publication Date: 2026.02.18 SANOFI SA(FR)
  • EP4208221B1 patent drawingFigure 1~2a
  • EP4208221B1 patent drawingFigure 2b~2d
  • EP4208221B1 patent drawingFigure 3a~3b

AI summary

The present invention refers to a switch assembly for an electronic system of a drug delivery device (1). The switch assembly comprises a chassis (19) supporting a PCBA (110) which has a distal surface comprising at least a first electrical contact (23a, 33a), a second electrical contact (23b, 33b) and a third electrical contact (23c, 33c), a ring (21, 31, 41, 51) having an annular ratchet profile (22,42, 52), and a first electrically conductive and elastically deformable arm (27, 36, 45, 56) and a second electrically conductive and elastically deformable arm (28, 37, 46, 60). The chassis (19) moves axially relative to the ring (21, 31, 41, 51) from a first axial position to a second axial position during a first switch operation mode. The chassis (19) and the ring (21, 31, 41, 51) are configured such that the ring (21, 31, 41, 51) rotates relative to the chassis (19) during a second switch operation mode. The first arm (27, 36, 45, 56) is arranged such that axial movement of the chassis (19) towards the ring (21, 31, 41, 51) during the first switch operation mode closes an electrical connection between the first electrical contact (23a, 33a) and the first arm (27, 36, 45, 56). Further, the ratchet profile (22, 42, 52) of the ring (21, 31, 41, 51) is located facing proximally towards the distal surface () of the PCBA (110) such that an actuator (24, 38, 49, 61) guided on the ratchet profile (22, 42, 52) at least during the second switch operation mode elastically deforms the second arm (28, 37, 46, 60) thereby alternately opening and closing an electrical connection between the second electrical contact (23b, 33b) and the third electrical contact (23c, 33c) via the second arm (28, 37, 46, 60).