Plunger rod and assembly having modified thread geometry
Inventors
Thompson, James • SHAFER GREENBERG, Lauren • SWEENEY, MATTHEW DYLAN
Assignees
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Publication Number
US-12109399-B2
Publication Date
2024-10-08
Expiration Date
Abstract
A fluid-dispensing syringe includes a barrel and a plunger assembly disposed within the barrel. The assembly includes a piston with an outer piston surface, an inner piston cavity with an inner piston surface and at least one female thread, and proximal and distal piston ends. The plunger rod includes a rod body having proximal and distal rod ends, with a threaded extension extending distally from the distal rod end. The threaded extension extends distally along a distal length and threadedly engages the at least one female thread along a portion of the distal length. The threaded extension has a ventilation feature configured to create a ventilation space between the threaded extension and the inner piston surface. The proximal piston end and the distal rod end are in spaced relation to form a primary fluid passageway portion from outside of the plunger assembly into the piston cavity.
Core Innovation
The disclosure provides a fluid-dispensing syringe plunger assembly in which a piston and a plunger rod engage via threaded engagement. The piston includes an inner piston cavity defined by an inner piston surface and a female thread, and the plunger rod includes a threaded extension extending distally from a distal-facing rod surface.
When the plunger rod is fully advanced distally relative to the piston, the threaded extension and the inner piston surface define a ventilation space. The proximal-facing piston surface and the distal-facing rod surface are spaced apart and define a primary fluid passageway that extends from outside of the plunger assembly into the inner piston cavity.
The inlet of the fluid passageway is defined by a space between an edge of the proximal-facing piston surface that intersects with the outer surface of the piston and an edge of the distal-facing rod surface that intersects with the outer surface of the plunger rod. The disclosure further describes auxiliary passages in the rod body that route external fluid to the ventilation space.
Claims Coverage
The independent claim set includes one independent claim, and the dependent claims refine the ventilation space, the fluid passageway, auxiliary passages, and sterilization. The core inventive features are the threaded engagement creating a ventilation space and the edge-defined inlet geometry connecting an outside fluid passageway to the inner piston cavity.
Ventilation space formed by threaded extension and inner piston surface
The threaded extension and the inner piston surface define a ventilation space when the plunger rod is fully advanced distally relative to the piston.
Edge-defined fluid passageway inlet into inner piston cavity
The proximal-facing piston surface and the distal-facing rod surface, when the plunger rod is fully advanced distally relative to the piston, are spaced apart and define a fluid passageway therebetween, and the inlet is defined by a space between edges intersecting the respective outer surfaces.
Threaded engagement between female thread and threaded extension
The threaded extension is configured to threadedly engage with the female thread along at least a portion of the length.
Auxiliary passage routing to the ventilation space
The plunger rod has an auxiliary passage connecting a ventilation space to the plunger rod’s outer distal end surface or outer side surface.
Sterilizing fluid introduction into inner piston cavity
A method of sterilizing a plunger assembly by introducing a sterilizing fluid such that fluid flows into the inner piston cavity.
The claims cover a plunger assembly where threaded engagement at a fully advanced condition creates a ventilation space between the threaded extension and the inner piston surface, while a spaced proximal piston surface and distal rod surface form a primary fluid passageway into the inner piston cavity. Dependent claims further specify the inlet geometry, auxiliary passages to the ventilation space, and sterilization by flowing sterilizing fluid into the inner piston cavity.
Stated Advantages
Enables introducing sterilizing fluid/disinfecting fluid into the inner piston cavity via the external space and the ventilation space/primary fluid passageway [procedural detail omitted for safety].
Documented Applications
Sterile plunger assemblies and sterile fluid-dispensing syringes prepared by flowing sterilizing fluid into the piston cavity via the external space outside the plunger assembly [procedural detail omitted for safety].
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