Auto-injector Cassette Shock Damping Mechanism
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Solution Overview
Problem
Auto-injectors with electrically powered drive systems face challenges in minimizing the effects of shock when the cassette unit is dropped or mishandled, potentially leading to syringe fracture due to the close proximity of the cassette unit end-cap and syringe flange, which limits deceleration and increases the risk of damage.
Innovation Solution
The introduction of a removable cap with needle cover gripping elements and a damping element between the cassette unit end-cap and syringe flange, allowing for limited axial travel of the cap insert and damping movement, respectively, to reduce the impact of shock and prevent syringe fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cassette unit end-cap and syringe flange are positioned in close proximity to minimize device size, then the device compactness is improved, but the risk of syringe fracture due to shock increases
Solution Approach 1:
A resilient element is positioned between the cassette unit end-cap and the syringe flange to provide cushioning before shock impacts occur. This resilient element absorbs and dissipates impact energy during accidental drops or mishandling, preventing direct transmission of shock forces to the syringe and eliminating the need for excessive spacing between components.
2Ease of manufacture
If the cassette unit is designed as a fully disposable single device, then manufacturing and sterilization are simplified, but cost-effectiveness and environmental impact worsen
Solution Approach 1:
The auto-injector is divided into two separable units: a reusable drive unit containing the electrically powered drive system and electronics, and a disposable cassette unit containing the syringe. The cassette unit can be detached and replaced after use, allowing the expensive and complex drive unit to be retained and reused multiple times, reducing waste and cost per injection.
3Ease of operation
If electrically powered drive systems are added to assist patients with compromised manual dexterity, then ease of operation is improved, but device complexity and cost increase
Solution Approach 1:
An electrically powered drive system acts as an intermediary between the patient's simple cap removal action and the complex task of injecting. The motorized drive automatically performs needle deployment, plunger actuation, and injection control when power is supplied, translating a simple user action into precise medical delivery while accommodating patients with limited manual dexterity.
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
These features effectively reduce the impact of shock and mishandling on the syringe, enhancing the durability and reliability of the auto-injector by allowing for controlled deceleration and minimizing the risk of syringe damage during accidental drops or improper handling.
Implementation Method 1
a damping element between the cassette unit end-cap and syringe flange, allowing for limited axial travel of the cap insert and damping movement, respectively, to reduce the impact of shock
Data Source
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AI summary
Provided is a cassette unit suitable for use with an auto-injector having a drive unit. The cassette unit comprises a cassette unit housing defining a cassette unit housing cavity arranged for receipt of a syringe; a needle projection aperture; a needle cover defining a needle sheath for sheathing of a needle tip of the syringe; a removable cap that in a capping position fits over and thereby, acts such as to close off, the needle projection aperture, the removable cap defining a cap interior; provided to the removable cap, a cap insert; and provided to the cap insert, a connector defining one or more needle cover gripping elements for gripping the needle cover and the connector defines a central hub and the one or more needle gripper elements attach to the central hub and in spaced arrangement relative to each other, wherein the connector locates within the removable cap such that the central hub of the connector is in spaced relationship with a forward end wall or surface of the cap interior and the needle cover gripping elements project away from the forward end cap wall or surface of the cap interior and towards the open end of the cap, and wherein the removable cap is shaped to allow for limited axial travel of the cap insert there within.