Autoinjector Syringe Carrier Assembly With Flexible Arm Positioning
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Solution Overview
Problem
Conventional injection devices, both manual and autoinjectors, face challenges such as the need for manual force application, potential premature release of the plunger, difficulty in aligning and stabilizing the device during injection, and dexterity requirements that may be beyond the capabilities of certain users, especially the elderly or children.
Innovation Solution
An autoinjector design featuring a syringe carrier with flexible arms that deflect inward due to axial force, facilitated by a ramp mechanism, allowing secure mounting and assembly of the syringe within a case, ensuring accurate positioning despite variations in syringe and needle shield dimensions, and enabling a simplified assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible arms are used to couple with the syringe, then secure positioning and support of the syringe is improved, but device complexity increases due to the need for deflection mechanisms
Solution Approach 1:
The patent employs flexible arms made of elastomeric material that can deflect radially inward to engage with the syringe. These flexible arms provide reliable positioning and coupling while accommodating dimensional variations through their elastic deformation, resolving the contradiction between secure positioning and structural complexity.
Solution Approach 2:
The flexible arms change their radial dimension through elastic deformation when subjected to axial force. This parameter change allows the arms to transition from a relaxed state to an engaged state, securing the syringe reliably without requiring complex mechanical actuation systems.
2Manufacturing precision
If a ramp mechanism is used to deflect flexible arms, then assembly process is simplified and positioning accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The ramp structure is pre-formed as an integral part of the syringe carrier housing during the molding process. This preliminary action ensures that when axial force is applied during assembly, the flexible arms are automatically guided to deflect along the predetermined ramp path, achieving accurate positioning without requiring additional assembly steps or complex manufacturing operations.
3Measurement precision
If protrusions with smaller outer diameter are used, then pre-positioning and support of the syringe is improved, but coupling strength with the syringe decreases
Solution Approach 1:
The coupling mechanism transitions from a static interference fit to a dynamic engagement process. The flexible arms initially engage with the syringe at the protrusions for precise pre-positioning, then continue to deflect and engage with the syringe flange under axial force, distributing the coupling strength across multiple contact points and resolving the contradiction between positioning precision and coupling strength.
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
The design ensures robust support and secure positioning of the syringe, simplifies assembly, and accommodates variations in syringe dimensions, enhancing user safety and ease of use by reducing the need for manual dexterity.
Implementation Method 1
two or more flexible arms protruding outwards in a relaxed state and adapted to couple with the syringe in a mounted position, wherein in the mounted position, the flexible arms are deflected radially inwards due, in part, to an axial force operating on the syringe carrier
Data Source
AI summary
The disclosure further relates to an autoinjector and a method of assembling the autoinjector. A syringe carrier is disclosed comprising a housing adapted to receive a syringe. They syringe includes a needle encapsulated by a removable protective needle sheath. The syringe carrier further includes two or more flexible arms protruding outwards in a relaxed state and adapted to couple with the syringe in a mounted position. In the mounted position, the flexible arms deflect radially inwards due, in part, to an axial force operating on the syringe carrier.