Self-Activating Injection Device with Cantilever Locking Tabs

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Solution Overview

Problem

Conventional syringes for sterile injections pose a higher risk of accidental needle sticks to medical professionals due to handling before and after injection, as they are typically filled just prior to use.

Innovation Solution

A pre-loaded, disposable syringe device with a sterile needle and cartridge, featuring a housing with cantilevered locking tabs and an adapter that moves between pre-armed and armed positions, allowing for sterile injection while maintaining sterility and preventing detachment during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional syringes are filled just prior to use, then sterility can be maintained, but the risk of accidental needle sticks increases due to handling before and after injection

Engineering Contradiction:

Improvesterility maintenanceVSAvoidaccidental needle stick risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cartridge is pre-filled and pre-sterilized with the injectable agent before use. The needle is pre-assembled in a safe, retracted position within the housing. This preliminary preparation eliminates the need for medical professionals to handle loose needles or perform filling operations, thereby maintaining sterility while reducing accidental needle stick risks.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The needle is nested within the housing in a retracted position, and the cartridge is nested within the housing as well. The needle can only be deployed when the cartridge is properly inserted and locked into position. This nested configuration ensures that the needle remains protected and inaccessible during storage and handling, eliminating accidental needle stick risks while maintaining sterility.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If the needle is separated from the cartridge in pre-armed position, then safety is improved, but device complexity increases due to movable adapter and locking mechanism

Engineering Contradiction:

Improveneedle stick preventionVSAvoidadapter and locking mechanism

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The adapter integrates multiple functions into a single component: it holds the needle, engages with the cartridge, and interfaces with the locking tabs. The locking tabs are integrated directly into the housing structure. This merging of functions reduces the number of separate parts and simplifies the overall mechanism while maintaining the safety benefits of needle separation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cantilevered locking tabs automatically engage with the adapter when the cartridge is inserted into the housing, and automatically disengage when the cartridge is removed. The spring-loaded nature of the tabs provides automatic locking and unlocking without requiring additional actuators or complex control mechanisms, thereby reducing device complexity while maintaining safety.

Inventive Principle:

Principle #25Self-service

3Reliability

If the adapter moves between pre-armed and armed positions, then sterility and safety are maintained, but ease of operation decreases due to precise positioning requirements

Engineering Contradiction:

Improvesterility maintenanceVSAvoidpositioning precision

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The cantilevered locking tabs are pre-positioned and spring-loaded to provide a tolerance zone for cartridge insertion. The tabs flex outward to accommodate slight variations in insertion position and then snap into the locked position. This beforehand cushioning through elastic deformation absorbs positioning errors and ensures reliable locking without requiring precise manual positioning by the user.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The locking tabs are designed as flexible, spring-loaded elements that dynamically adapt to the insertion force and position of the cartridge. During insertion, the tabs flex outward to accommodate the cartridge, then automatically snap into the locked position when engaged. This dynamic behavior simplifies operation by eliminating the need for precise positioning while maintaining secure locking and sterility.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10603439B2Sealed self-activating injection device for delivery of medicine from a prefilled cartridge or vial

Publication Date: 2020.03.31 KPR U S LLC

AI summary

The disclosed embodiment relates to an injection device that is a single patient use, disposable device containing a needle and a cartridge containing a drug or pharmaceutical product. The device is initially provided in a pre-armed configuration wherein the needle sheath maintains cantilever locking tabs on the housing in a position to the maintain the needle in a position separated from the septum of a cartridge. To arm the device, the practitioner removes the needle sheath and pushes down the plunger assembly. The cantilever locking tabs flex outwardly thereby allowing the cartridge-to-housing interface and the cartridge to move forward whereby the butt end of the needle punctures the septum of the cartridge. Additionally, the cantilever locking tabs form a stop configuration with the housing of the device. The disclosed embodiment is particularly adaptable to dental anesthetic applications, as well as other medical and veterinary applications.