Telescoping plunger rod

Patent metadata

Field	Value
Publication number	US-11801349-B2
Application number	US-202117242085-A
Country	US
Kind code	B2
Filing date	Apr 27, 2021
Priority date	Apr 27, 2021
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

Devices and methods for use with syringes are disclosed. A plunger rod includes an outer housing having proximal and distal ends and a lumen between the ends, as well as an inner body axially slidable within the lumen between a first and second position. The inner body has a retention member extending therefrom. When the inner body is in the first position, the plunger rod has a first length, and, when the inner body is in the second position, the plunger rod has a second length greater than the first length. When the inner body is in the second position, the inner body is configured to be rotated relative to the outer housing until the retention member is received within the outer housing to preclude the inner body from moving in the axial direction.

First claim

What is claimed is:

1. A plunger rod for use with a syringe, the plunger rod comprising:
an outer housing having a proximal end and a distal end opposite the proximal end, and further defining a lumen between the proximal end and the distal end; and
an inner body configured to be movable within the lumen between a first position and a second position along an axial direction, the inner body comprising a retention member extending outward from the inner body in a direction angularly offset from the axial direction,
wherein, when the inner body is in the first position relative to the outer housing, the plunger rod has a first length, and, when the inner body is in the second position relative to the outer housing, the plunger rod has a second length greater than the first length, and
wherein, when the inner body is in the first position relative to the outer housing, the inner body is precluded from being rotated relative to the outer housing, and when the inner body is in the second position relative to the outer housing, the inner body is configured to be rotated relative to the outer housing until the retention member is received within a channel of the outer housing to preclude the inner body from moving relative to the outer housing in the axial direction.

2. The plunger rod of claim 1 , wherein the outer housing defines a plurality of channels, including the channel, that are spaced along the axial direction, each of the plurality of channels being configured to receive the retention member.

3. The plunger rod of claim 2 , wherein the plurality of channels include a distal channel, the channel is an intermediate channel adjacent the distal channel, and the retention member is configured to be received in the distal channel when the inner body is in the first position relative to the outer housing.

4. The plunger rod of claim 3 , wherein the plurality of channels include a proximal channel spaced from the distal channel and the intermediate channel, the proximal channel configured to receive the retention member therein, and
wherein, when the retention member is received in the proximal channel, the inner body is precluded from being rotated relative to the outer housing.

5. The plunger rod of claim 3 , wherein the distal channel is tapered in the axial direction towards the distal end of the outer housing.

6. The plunger rod of claim 1 , wherein the outer housing defines a contact surface in communication with the lumen, the contact surface contacting a face defined on the inner body after the inner body is rotated relative to the outer housing to the second position.

7. The plunger rod of claim 6 , wherein the face of the inner body and the contact surface of the outer housing are in a friction fit when the face is in contact with the contact surface to resist relative rotation between the inner body and the outer housing.

8. The plunger rod of claim 6 , wherein the contact surface includes a retention member contact surface and an inner body contact surface,
wherein the face of the inner body is defined by the distal end of the inner body and by the retention member, and
wherein the retention member contact surface is configured to contact the portion of the face defined by the retention member, and the inner body contact surface is configured to contact the portion of the face defined by the inner body that does not define the retention member.

9. The plunger rod of claim 8 , wherein, when the inner body is in the second position, the inner body is configured to receive an axial force applied thereto and to transfer the axial force therefrom to the outer housing via the contact between the face of the inner body and the contact surface of the outer housing.

10. The plunger rod of claim 6 , wherein the contact surface includes a lower contact surface and an upper contact surface spaced from the lower contact surface, wherein the retention member of the inner body is configured to be received into a space defined between the upper contact surface and the lower contact surface and to be in friction fit with the upper contact surface and the lower contact surface.

11. The plunger rod of claim 6 , wherein one of the contact surface and the face of the inner body defines a notch thereon, and the other of the contact surface and the face defines a protrusion thereon, and
wherein, when the inner body is rotated relative to the outer housing while the inner body is in the second position, the protrusion is receivable in the notch.

12. The plunger rod of claim 11 , wherein rotation of the inner body relative to the outer housing in a first rotational direction causes the protrusion to be moved into the notch, such that the protrusion is configured to contact at least one wall of the notch to preclude rotation of the inner body relative to the outer housing in a second rotational direction opposite the first rotational direction.

13. The plunger rod of claim 11 , wherein the protrusion is disposed on the face, and the notch is disposed on the contact surface of the outer housing.

14. The plunger rod of claim 11 , further comprising a plurality of the protrusions and a plurality of the notches, wherein the number of the plurality of the protrusions is the same as the number of the plurality of the notches.

15. The plunger rod of claim 1 , wherein the retention member includes a base extending from the inner body and a resilient protrusion extending from the base,
wherein the resilient protrusion is configured to be deformed by application of a force, and resiliently undeforms upon removal of the force.

16. The plunger rod of claim 15 , wherein the outer housing defines a detent extending into the lumen that is configured to be contacted by the retention member,
wherein, upon contact with the detent, the resilient protrusion is configured to deform due to the contact and due to application of the force, such that the retention member is moved past the detent, and
wherein the resilient protrusion resiliently returns to its original configuration when the resilient protrusion is moved past the detent to prevent separation of the inner body from the outer housing based on interaction between the resilient protrusion and the detent.

17. The plunger rod of claim 1 , further comprising a plunger disposed adjacent to the distal end of the outer housing, such that the plunger is configured to contact a liquid within the syringe to cause dispensing thereof from the syringe.

18. A syringe assembly comprising:
a syringe configured to receive a liquid therein;
a plunger rod configured to be slidably received within the syringe, the plunger rod including:
an outer housing having a proximal end and a distal end opposite the proximal end, and further defining a lumen between the proximal end and the distal end; and
an inner body configured to be movable within the lumen between a first position and a second position along an axial direction, the inner body comprising a retention member extending outward from the inner body in a direction angularly offset from the axial direction; and

a plunger disposed on the outer housing,
wherein, when the inner body is in the first position relative to the outer housing, the plunger rod has a first length, and, when the inner body is in the second position relative to the outer housing, the plunger rod has a second length greater than the first length, and
wherein, when the inner body is in the first position relative to the outer housing, wherein, when the inner body is in the first position relative to the outer housing, the

Assignees

• Fresenius Kabi Usa Llc
• Fresenius Kabi Austria Gmbh

Inventors

• Murray Christopher J
• Attermeier Kurt
• Zauner Christoph

Classifications

• A61M5/3158 Primary

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

• A61M5/31511 Primary

  Piston or piston-rod constructions, e.g. connection of piston with piston-rod (A61M5/5066 takes precedence) · CPC title

• A61M2005/3151

  by friction · CPC title

• A61M2202/0007

  introduced into the body · CPC title

• A61M2005/31518

  designed to reduce the overall size of an injection device, e.g. using flexible or pivotally connected chain-like rod members · CPC title