Reservoir Holder Lock Mechanism for One-Push Injection Attachment

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Solution Overview

Problem

Existing drug delivery devices require complex movements, such as linear and rotational actions, for attaching and locking reservoir holders, which can be challenging for individuals with dexterity issues.

Innovation Solution

A lock mechanism that allows for a simple, longitudinal attachment and locking of a reservoir holder to a housing, using a first and second sloped surface to guide and rotate a lock member, preventing rotation during attachment and ensuring stable locking through a spring-biased mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bayonet-like connection with sloped section and circumferential section is used to attach the cartridge holder to the housing, then the attachment provides reliable and releasable connection, but the attachment procedure requires linear and rotational movements which constitutes a barrier for people with dexterity problems

Engineering Contradiction:
Improveattachment reliabilityVSAvoidattachment ease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of requiring rotation to achieve locking (conventional bayonet connection), the invention inverts the sequence by using longitudinal movement to trigger automatic rotation of the lock member. The sloped surface converts the longitudinal attachment movement into rotational movement of the lock member, which then engages the stop surface to provide locking. This inversion makes the operation simpler for users with dexterity issues.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The lock member automatically rotates and locks itself during the longitudinal attachment movement without requiring the user to perform separate rotational or locking actions. The sloped surface and stop surface arrangement enables the lock member to self-engage and self-lock as the cartridge holder is simply pushed onto the housing, making the system self-servicing during attachment.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If a lock member with sloped surface and stop surface is used to enable simple longitudinal attachment movement, then the ease of operation is improved, but the device complexity increases due to additional guiding elements and lock member components

Engineering Contradiction:
Improveattachment ease of operationVSAvoidlock mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention merges the locking function and guiding function into a unified lock member structure. The lock member simultaneously provides the sloped surface for converting longitudinal movement to rotation, the stop surface for locking engagement, and acts as part of the guiding system through its interaction with the cartridge holder. This merging reduces the need for separate complex guiding mechanisms while achieving both simple operation and reliable locking.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lock member serves multiple functions: it guides the attachment movement through its sloped surface, converts longitudinal motion to rotational motion, provides the locking engagement through the stop surface, and prevents unintended rotation when engaged. This multi-functionality consolidates what would otherwise require multiple separate components, managing device complexity while achieving versatile operation.

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

Enables easy and secure attachment and locking of the reservoir holder without requiring complex movements, maintaining a compact design and preventing unintentional release, suitable for users with dexterity challenges.

Implementation Method 1

a spring member adapted to bias the lock member; the biased spring biases the lock member in its rotated position

Methodology Applied
Scientific EffectSpring biasing: Spring

Implementation Method 2

the first and second sloped surface are pressed against each other and subsequently slide along each other thereby causing the lock member to rotate

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4702998A1Lock mechanism for a reservoir holder of a drug delivery device
Publication Date: 2026.03.04 YPSOMED AG
  • EP4702998A1 patent drawingFigure 1~2
  • EP4702998A1 patent drawingFigure 3~6
  • EP4702998A1 patent drawingFigure 7a~10c

AI summary

The invention relates to a lock mechanism (10) for locking a distal reservoir holder (20) to a proximal part (6) of an injection device (1). The reservoir holder (20) comprises a first longitudinal guiding element (21), a proximally directed first sloped surface (31) and a distally directed first stop surface (35). The proximal part (6) comprises a second longitudinal guiding element (62) and a rotatable lock member (40) which includes a distally directed second sloped surface (51) and a proximally directed second stop surface (55). During an attachment movement of the reservoir holder (20) the first and second guiding element (21, 62) are coupled to each other and the first and second sloped surface (31, 51) are pressed against each other and subsequently slide along each other thereby causing the lock member (40) from a start position towards a rotated position.