Cartridge and pump with axial loading

• US 7,510,544 B2
• Filed: 06/15/2005
• Issued: 03/31/2009
• Est. Priority Date: 02/28/2002
• Status: Expired due to Fees

• Current Assignee: Smiths Medical ASD, Inc. (Smiths Group International Holdings Ltd.)
• Original Assignee: Smiths Medical MD Incorporated
• Inventors: Faust, Mark Henry, Bynum, Gail Beth, Vilks, Clinton S.
• Primary Examiner(s): Lucchesi; Nicholas D
• Assistant Examiner(s): Stigell; Theodore J
• Application Number:
  US11/152,880
• Publication Number:
  US 20050234404A1
• Time in Patent Office: 1,385 Days
• Field of Search: 604/131, 604/151, 604/155, 604/228, 604/152, 604/154, 604/218
• US Class Current: 604/151
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2205/75 with filters
• CPC Class Codes: A61M 2205/82 Internal energy supply devices
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/16859 Evaluation of pressure response, e.g. to an applied pulse

Abstract

The present invention concerns a medication pump for use with a medication cartridge that is loaded using a drive rod of the medication pump. In one embodiment, the drive rod includes an interface structure defining a first channel where the first channel has an axial portion disposed parallel to an axis of the drive rod and a locking portion disposed in a circumferential direction around an outer surface of the drive rod. In another embodiment of the invention, the drive rod includes a visual indicator at an interface end of the drive rod, so that when the interface structure of the drive rod is coupled to a plunger of a medication cartridge, the visual indicator will not be seen, to provide a way to check for secure coupling of the drive rod to the plunger. In its embodiment, the outer housing of the medication pump includes a window into a cartridge housing to allow a view of the visual indicator if it is not attached to the plunger. In another embodiment the medication pump includes a pump cap that has guides located on an interior surface. These guides engage axial guides on a medication cartridge, so that when the pump cap is rotated, it causes rotation of the medication cartridge so that the medication cartridge is rotated into engagement with the interface structure of the drive rod.

Claims

1. A medication pump comprising:

a motor;

a cartridge chamber for receiving a medication cartridge, the chamber comprising a first open end for receiving the medication cartridge and a second end, the second end defining a drive rod opening;

a drive rod comprising an interface end, wherein the interface end of the drive rod extends into the cartridge chamber through the drive rod opening, wherein the drive rod is configured to be axially moved by the motor, the drive rod comprising an interface structure at the interface end, the interface structure defining a first channel, the first channel comprising an axial portion disposed parallel to an axis of the drive rod and a locking portion disposed in a circumferential direction around an outer surface of the interface structure, wherein the interface structure includes a channel end wall defining a terminal end of the locking portion of the first channel;

a medication cartridge for loading in the cartridge chamber, the medication cartridge including a cylindrical barrel comprising an open end and a closed end, the closed end defining an orifice, and a plunger slidably received in the barrel, the plunger comprising a cylindrical wall having an interior cylindrical wall face, wherein a first tab projects inwardly from the interior wall face, wherein the medication cartridge comprises axial guides at an exterior surface of the closed end; and

a pump cap configured to rotationally attach to the open end of the cartridge chamber to close the cartridge chamber, the pump cap having an interior surface comprising guides that engage the axial guides at the closed end of the medication cartridge, wherein when the pump cap is rotated into engagement with the open end of the cartridge chamber, the cartridge is rotated in a first direction to move the tab into the locking portion of the channel on the drive rod interface structure.

2. The medication pump of claim 1 wherein the interface structure further defines a second channel comprising an axial portion disposed parallel to the axis of the drive rod and a locking portion disposed in a circumferential direction around the outer surface of the interface structure.

3. The medication pump of claim 1, wherein the interface structure of the drive rod comprises a visual indicator, wherein when the interface structure is coupled to a plunger, the visual indicator is positioned within the plunger, the pump further comprising an outer housing enclosing the motor, drive rod and cartridge chamber, wherein the outer housing comprises a window into the cartridge chamber.

4. The medication pump of claim 3 wherein the visual indicator comprises a dark colored portion of the interface structure.

5. The medication pump of claim 3 wherein the visual indicator comprises a bright colored portion of the interface structure.

6. The medication pump of claim 1 wherein when the pump cap is rotated out of engagement with the open end of the cartridge chamber, the cartridge is rotated in a second direction opposite the first direction to move the tab into the axial portion of the channel on the drive rod interface structure.

7. A medication pump system comprising:

a motor;

a cartridge chamber for receiving a medication cartridge, the chamber comprising a first open end for receiving the medication cartridge and a second end, the second end defining a drive rod opening;

a drive rod comprising an interface end, wherein the interface end of the drive rod extends into the cartridge chamber through the drive rod opening, wherein the drive rod is configured to be axially moved by the motor, the drive rod comprising an interface structure at the interface end, the interface structure defining a first channel, the first channel comprising an axial portion disposed parallel to an axis of the drive rod and a locking portion disposed in a circumferential direction around an outer surface of the interface structure, wherein the interface structure includes a channel end wall defining a terminal end of the locking portion of the first channel;

a pump cap for rotationally attaching to the open end of the cartridge chamber to close the cartridge chamber, the pump cap comprising guides located on an interior surface that engage axial guides at a closed end of a medication cartridge, wherein when the pump cap is rotated into engagement with the open end of the cartridge chamber, the cartridge is rotated into engagement with the interface structure of the drive rod.

8. The medication pump system of claim 7 further comprising a medication cartridge for loading in the cartridge chamber, the medication cartridge comprising:

a cylindrical barrel comprising an open end and a closed end, the closed end defining an orifice;

a plunger slidably received in the barrel, the plunger configured to connect to the interface structure of the drive rod; and

axial guides at an exterior surface of the closed end.