Injection Device Nested Spring Mechanism for High-Viscosity Medicaments

The patent employs a nested spring configuration where a first compression spring is positioned within a first cylindrical cavity and a second compression spring is positioned within a second cylindrical cavity, with both springs working in sequence to deliver high force while maintaining a compact device footprint. This nested arrangement allows multiple energy-storing elements to occupy overlapping spatial volumes, effectively reducing the overall device size while maintaining the required injection force capability.

The patent divides the single high-force spring into multiple smaller compression springs (first and second springs) that operate in sequence. Each spring is contained within its own cylindrical cavity and contributes to the total injection force. This segmentation allows the force generation function to be distributed across multiple smaller components rather than requiring one large spring, thereby reducing the overall device volume while maintaining adequate injection force.

The patent incorporates a visible indicator mechanism that provides visual feedback to the user during injection. The indicator likely changes position, color, or visibility state to communicate injection progress, allowing users to monitor slow injections in real-time. This visual signaling system addresses the difficulty of detecting injection progress by translating mechanical movement into easily observable visual changes.

The patent implements a feedback mechanism through the visible indicator that continuously communicates injection status to the user. As the plunger moves and medicament is delivered, the indicator provides real-time visual feedback about the injection progress, enabling users to understand whether the injection is complete or still in progress, even when the injection rate is slow.

The patent employs a launch mechanism that pre-positions and pre-charges the injection system before actual medicament delivery. The launch mechanism uses compression springs to rapidly advance the plunger to an initial position, preparing the system for controlled medicament expulsion. This preliminary action separates the complex mechanical preparation from the simple injection execution, making the device easier to operate while containing complexity in the pre-positioning mechanism.

The patent implements automatic needle penetration and injection functions that operate without continuous user intervention. Once activated, the compression springs automatically drive the plunger to penetrate the needle and deliver the medicament. The device performs these critical functions autonomously, reducing the operational burden on patients while the complexity is confined to the automatic drive mechanism rather than the user interface.