Transdermal Patch Pump Cam Needle Actuation

The patent combines the needle insertion and withdrawal actuation functions into a single integrated cam mechanism. The cam profile is designed with specific geometric features that simultaneously control both the insertion stroke (when the cam surface contacts the needle holder) and the withdrawal stroke (when the cam surface releases and the spring returns the needle). This merging of functions into a single mechanism eliminates the need for separate biasing elements for each direction, thereby improving reliability while maintaining versatility.

The cam mechanism acts as an intermediary element that translates rotational motion into the complex linear motion required for both needle insertion and withdrawal. The cam profile serves as a mediator between the simple rotational actuation and the compound linear movements needed for safe and reliable needle handling, eliminating the need for separate complex actuation systems for each function.

The patent extracts and eliminates the septum component from the fluid connection system. Instead of using a septum that must be pierced (which creates contamination risks), the invention employs a direct fluid communication pathway between the reservoir and the cannula through precisely engineered fluid ports and channels. This removal of the septum eliminates the source of contamination while maintaining the ability to establish fluid connection.

The patent employs a disposable sterile barrier膜 (membrane) that is integrated into the reservoir-cannula connection system. This thin, sterile barrier is disposed of with the entire device after single use, eliminating the need for reusable septa that require piercing. The disposable nature ensures sterile conditions while maintaining ease of fluid connection establishment.

The patent introduces dynamic adjustability to the pump system through a variable piston stroke mechanism. The piston stroke length can be dynamically adjusted within a range, allowing the pumped volume to be varied according to different application requirements. This dynamic capability is achieved through adjustable positioning mechanisms or variable geometry designs that maintain relative simplicity while providing adaptability.

The patent enables volume variation by changing the geometric parameters of the piston stroke rather than fundamentally redesigning the pump structure. By adjusting parameters such as piston displacement distance or chamber volume, the system achieves versatility for different applications while maintaining a relatively simple base pump design. This parameter-based adjustment allows flexible volume control without proportionally increasing complexity.

The patent applies local quality optimization by designing the needle and cannula interface with specific geometric and material properties tailored to thin gauge requirements. The needle holder and cannula holder are designed with localized features such as reduced friction surfaces, optimized engagement geometries, and appropriate material selections that ensure reliable operation with thin components while maintaining patient comfort.

The patent adjusts key parameters of the transdermal delivery system to accommodate thin needle and cannula specifications. This includes modifying the insertion force parameters, engagement geometry parameters, and fluid flow parameters to ensure effective delivery while using thinner gauge components. These parameter changes enable the system to maintain reliability with improved patient comfort.