Multiple dosage injector with rotating screw dosage system

Patent metadata

Field	Value
Publication number	US-10300207-B2
Application number	US-201414771300-A
Country	US
Kind code	B2
Filing date	Mar 12, 2014
Priority date	Mar 13, 2013
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A dispensing mechanism for delivering a dosage of medicament including a housing having a proximal-distal axis; a plunger rod having a screw thread and configured to advance along the proximal-distal axis relative to the housing; a user-operable push button moveable along the proximal-distal axis relative to the housing; a twist driver threadably engaged with the push button such that movement of the push button towards the distal end of the housing causes rotation of the twist driver about the proximal-distal axis; and a driver engaged with the twist driver such that rotation of the twist driver causes rotation of the driver, the driver also engaged with a portion of the plunger rod such that rotation of the driver causes rotation of the plunger rod, advancing the plunger rod along the proximal-distal axis relative to the housing.

First claim

The invention claimed is:

1. A dispensing mechanism, comprising:
a housing having a proximal-distal axis;
a plunger rod having a screw thread and configured to advance along the proximal-distal axis relative to the housing;
a user-operable push button moveable along the proximal-distal axis relative to the housing;
a twist driver threadably engaged with the user-operable push button such that movement of the user-operable push button along the proximal-distal axis relative to the housing causes rotation of the twist driver about the proximal-distal axis;
a driver engaged with the twist driver such that rotation of the twist driver causes rotation of the driver, the driver also engaged with a portion of the plunger rod such that rotation of the driver causes rotation of the plunger rod, advancing the plunger rod along the proximal-distal axis relative to the housing; and
an anti-reverse mechanism including:
at least one ratchet integrally formed on an internal surface of the housing; and
a flexible column integrally formed with a sidewall defining a side opening of the user-operable push button, the flexible column having a flexible column protrusion at a proximal end thereof,

wherein as the user-operable push button moves along the proximal-distal axis, the flexible column protrusion engages the at least one ratchet and restricts movement of the user-operable push button to one direction during a firing motion and a resetting motion.

2. An injector comprising:
the dispensing mechanism of claim 1 ,
a cartridge disposed within the housing;
a plunger disposed in the cartridge, wherein the plunger rod is associated with the plunger for forcing the plunger in a distal direction; and
a needle in fluid communication with the cartridge.

3. The dispensing mechanism of claim 1 , wherein the flexible column protrusion is generally elliptically shaped.

4. The dispensing mechanism of claim 1 , further comprising:
a nut fixated within the housing having protrusions on an internal surface that engage the screw thread of plunger rod such that as the plunger rod rotates, the plunger rod is advanced along the proximal-distal axis relative to the housing.

5. The dispensing mechanism of claim 1 , wherein the twist driver further includes a ratchet flap that is configured to engage a lip of the driver such that the twist driver can axially rotate about the proximal-distal axis in generally only one direction.

6. The dispensing mechanism of claim 1 , further comprising a biasing member disposed within the user-operable push button to facilitate movement of the user-operable push button from a fired position to a reset position.

Assignees

• Newton Benjamin
• Madsen Patrick
• Rust Matthew
• Cox Janice
• Antares Pharma Inc

Inventors

• Newton Benjamin
• Madsen Patrick
• Rust Matthew
• Cox Janice

Classifications

• A61M5/31543 Primary

  piston rod reset means, i.e. means for causing or facilitating retraction of piston rod to its starting position during cartridge change · CPC title

• A61M2005/2407

  from the rear · CPC title

• G01F11/023

  with provision for varying the stroke of the piston · CPC title

• A61M5/31536 Primary

  Blocking means to immobilize a selected dose, e.g. to administer equal doses · CPC title

• A61M5/31585

  performed by axially moving actuator, e.g. an injection button · CPC title