Auto-Injector Safety Cap Segmentation for Orientation Control

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Solution Overview

Problem

Existing injection devices often lead to misorientation during the injection process, resulting in potential unwanted puncture injuries due to the design that allows the safety cap to be completely removed, confusing users about the correct end to apply the injection.

Innovation Solution

The injection device features a security assembly with a guide arrangement that limits the axial adjustment path of the safety cap, keeping it attached to the base housing even in the release position, and includes an actuation cap with locking means to ensure proper orientation and prevent misorientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the safety cap is designed to be completely removed from the base housing, then the user can easily access the injection mechanism, but the user may become confused about the correct orientation and cause misorientation during injection

Engineering Contradiction:
Improveaccess to injection mechanismVSAvoidcorrect orientation during injection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The safety cap is segmented into two functional parts: a removable actuating cap that provides access to the release mechanism, and a retained locking cap that maintains orientation guidance. This segmentation allows the user to remove the actuating cap for access while the locking cap remains to prevent misorientation confusion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking cap serves as an intermediary element that remains between the user and the base housing after the actuating cap is removed. It acts as a visual and physical mediator that confirms correct orientation without blocking access to the release mechanism through the opening in its cap wall.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the safety cap is kept attached to the base housing in the release position, then misorientation is prevented, but the user cannot remove the cap-shaped component as previously done

Engineering Contradiction:
Improveprevention of misorientationVSAvoidremoval of cap component
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The safety cap is divided into a removable actuating cap and a retained locking cap. The actuating cap can be removed for access, while the locking cap remains attached to maintain orientation guidance. This segmentation resolves the contradiction by allowing partial removal rather than complete removal or complete retention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution moves from a single-cap design to a two-cap design, adding a dimensional layer to the safety cap structure. This allows different parts of the cap to have different retention characteristics, enabling both removal for access and retention for orientation guidance simultaneously.

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

3Ease of operation

If an opening is provided in the cap wall of the locking cap, then the locking pin can engage the retaining arm, but the structural integrity of the cap is reduced

Engineering Contradiction:
Improveengagement of locking mechanismVSAvoidstructural integrity of cap wall
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The cap wall has different local qualities: most of the cap wall maintains full structural integrity, while a localized opening is provided specifically for locking pin engagement. This local modification provides the necessary functionality without significantly compromising the overall structural strength of the cap.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3352817B1Injection device, in particular an auto-injector
Publication Date: 2021.03.24 PHARMA CONSULT GMBH & CO NFG KG
  • EP3352817B1 patent drawingFigure 1
  • EP3352817B1 patent drawingFigure 2~3
  • EP3352817B1 patent drawingFigure 4

AI summary

The invention relates to an auto-injector with a base housing (2), a carpule (6), a needle arrangement (7), at least one drive assembly (8), and a securing assembly (9) which secures the drive assembly (8) in its position with respect to the base housing (2) until activated for the injection procedure. The securing assembly (9) comprises a securing cap (12) with a cap jacket (14), a cap wall (15), and a securing pin (16) arranged inside the cap jacket (14). Arranged between the securing cap (12) and the base housing (2) is a guide arrangement (17) with a first and a second guide element (19, 20), which guide elements (19, 20) define an adjustment path (18) delimited in the axial direction on the side directed away from the distal end (3). In its release position, the securing cap (12) is still arranged and held on the base housing (2).