Pen Needle Shroud Sequencing for Complete Medicament Delivery

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing pen needle devices face issues with premature deployment of shields or shrouds, leading to incomplete medicament injection or skin deposition, which can occur if the shield deploys before the injection is complete.

Innovation Solution

A pen needle design featuring a distal shroud controlled by a distal compression spring and a proximal member that ensures the distal shroud deploys only after the proximal shroud has covered the needle, using a combination of springs and engagement formations to manage the shroud's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a spring-loaded shield is provided that can be automatically activated when the needle is withdrawn from the injection site, then needle-stick injury risk is reduced, but premature deployment may occur leading to incomplete medicament injection or skin deposition

Engineering Contradiction:

Improveneedle-stick injury riskVSAvoidinjection completeness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The shield is divided into two separate parts: a proximal shroud and a distal shroud. The proximal shroud deploys first to cover the proximal end of the needle, while the distal shroud remains constrained until after injection completion. This segmentation allows different deployment timing for different portions of the needle, preventing premature deployment while maintaining safety.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The proximal shroud is designed to deploy in advance (preliminary action) before the distal shroud. The proximal shroud's deployment is triggered by cartridge removal, which occurs before the injection sequence completes. This preliminary deployment of the proximal shroud prepares the system for subsequent distal shroud deployment at the appropriate time, ensuring injection completeness while maintaining safety.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the shield deploys automatically upon needle withdrawal, then safety is improved, but the injection process may be interrupted before completion

Engineering Contradiction:

Improveautomatic shield deploymentVSAvoidinjection speed

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The shield deployment mechanism is designed to be dynamic and sequential rather than simultaneous. The proximal shroud can deploy dynamically in response to cartridge removal, while the distal shroud remains dynamically constrained during injection and only deploys after injection completion is detected. This dynamic, staged approach maintains automatic operation while ensuring injection productivity.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If a distal compression spring is used to urge the distal shroud towards the distal opening, then shroud deployment is facilitated, but premature projection may occur

Engineering Contradiction:

Improveshroud deploymentVSAvoidpremature deployment timing

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The distal shroud is equipped with formations that can engage with corresponding formations in the housing to prevent premature distal movement. These engagement formations create a preliminary anti-action that counteracts the distal compression spring's urging force before injection completion. Only after the proximal shroud has deployed and injection is complete do these engagement formations disengage, allowing the distal shroud to project safely.

Inventive Principle:

Principle #9Preliminary anti-action

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

This design effectively prevents premature deployment of the distal shroud, ensuring complete medicament delivery and reducing the risk of medicament deposition on the skin, while providing protection against needle-stick injuries.

Implementation Method 1

a distal compression spring positioned around the needle and located between the needle carrier and the distal shroud, wherein the compression spring acts to urge the distal shroud away from the needle carrier towards the distal opening

Methodology Applied

Scientific EffectCompression spring: Spring

Implementation Method 2

a proximal compression spring positioned around the needle and located between the needle and the proximal shroud, wherein the proximal compression spring acts to urge the proximal shroud away from the needle carrier towards the proximal opening

Methodology Applied

Scientific EffectCompression spring: Spring

Data Source

PatentUS12420030B2Pen needle

Publication Date: 2025.09.23 OWEN MUMFORD

AI summary

A pen needle and a method of using the pen needle. The pen needle includes a housing, a needle carrier in the housing supporting a needle, a distal shroud positioned around the needle within the housing, a distal compression spring positioned around the needle between the needle carrier and the distal shroud, a proximal shroud positioned around the needle within the housing, and a proximal compression spring positioned around the needle between the needle and the proximal shroud. The proximal shroud is movable between a first position, in which the proximal shroud engages the distal shroud to hold the distal shroud in engagement with the housing, and a second position in which the proximal shroud is disengaged from the distal shroud allowing the distal shroud to move in a distal direction to project from the housing and surround a distal end of the needle.