Automatic injection device having a passive drive system with a shape memory spring

Patent metadata

Field	Value
Publication number	US-11311670-B2
Application number	US-201816159571-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	Oct 12, 2018
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

An automatic injection device has an insertion needle configured to be inserted into a patient and a drug container which contains a pharmaceutical product and includes a plunger. The automatic injection device also has a fluid path which fluidly connects the drug container to the insertion needle, and a drive system configured to cause linear movement of the plunger to force the pharmaceutical product into the fluid path. The passive drive system has a movable element. The movable element has a shape memory alloy and is configured to change shape to move the plunger.

First claim

What is claimed is:

1. An apparatus for use in an automatic injection device, the apparatus comprising:
a drug container configured to include a pharmaceutical product and including a first longitudinal end and a second longitudinal end with a drug flow opening;
a plunger that fits within the drug container;
a movable element made of a shape memory alloy, having a first end and a second end, located within the drug container, where the second end of the movable element abuts the plunger and urges the plunger toward the second longitudinal end of the drug container by expanding based on shape memory properties of the movable element; and
a drive system comprising the movable element, a mechanical restrictor operatively coupled to the movable element, and a holding means adjacent to the first longitudinal end of the drug container, wherein
the movable element is comprised of a spring body,
the spring body comprises a plurality of openings,
the spring body comprises a plurality of interconnected arms formed of the shape memory alloy, having an upper surface and a lower surface,
the upper surface and the lower surface of each arm of the plurality of interconnected arms is substantially free from contact with the upper surface and the lower surface of all arms of the plurality of interconnected arms in both an extended state of the spring body and in a compressed state of the spring body,
the spring body is located within the drug container in both the extended state and the compressed state,
the holding means comprises a wire that couples with the movable element and holds the movable element in the compressed state preventing the movable element from moving to the extended state,
the mechanical restrictor comprises a ratchet mechanism that further regulates movement of the plunger from the compressed state to the extended state at a proscribed rate upon release of the holding means from the movable element, and
the drive system provides a small form factor which allows the automatic injection device to be compact.

2. The apparatus for use in the automatic injection device of claim 1 , wherein the shape memory properties include the spring body returning to the extended state after being compressed.

3. The apparatus for use in the automatic injection device of claim 1 , wherein the spring body is configured to move from the compressed state to the extended state under a substantially constant force.

4. The apparatus for use in the automatic injection device of claim 1 , wherein the spring body moves the plunger in a linear direction from the first longitudinal end towards the second longitudinal end in the extended state.

5. The apparatus for use in the automatic injection device of claim 4 , wherein:
each opening of the plurality of openings begins at a first end opening proximal to an outer edge of the spring body and turns inward along a non-linear pathway along a length of each opening of the plurality of openings to a second end opening proximal to a center of the spring body, and
each opening of the plurality of openings overlaps with itself along a reference line of the spring body extending through the center to opposing surfaces of the outer edge.

6. The apparatus for use in the automatic injection device of claim 5 , wherein:
the first ends of each opening of the plurality of openings are angularly staggered relatively along the outer edge,
the second ends of each opening of the plurality of openings are angularly staggered relatively around the center.

7. The apparatus for use in the automatic injection device of claim 5 , wherein in the compressed state the plurality of arms borders the plurality of openings.

8. The apparatus for use in the automatic injection device of claim 5 , wherein in the compressed state, the spring body comprises a first planar surface, a second planar surface, and a thickness of the outer edge extending between the first planar surface and the second planar surface.

9. The apparatus for use in the automatic injection device of claim 5 , wherein the spring body in the compressed state has a disc profile.

10. The apparatus for use in the automatic injection device of claim 5 , wherein the spring body has a greater compression ratio than a coiled-shaped spring body made of the shape memory alloy.

11. The apparatus for use in the automatic injection device of claim 5 , wherein a width of each opening of the plurality of openings is not constant along the length.

12. The apparatus for use in the automatic injection device of claim 1 , wherein the shape memory alloy has a first shape configuration under a first input condition and a second shape configuration under a second input condition, such that the second input condition drives the spring body to be in the extended state.

13. The apparatus for use in the automatic injection device of claim 1 , wherein the spring body is formed from a single spring body unit or a plurality of spring body units.

14. The apparatus for use in the automatic injection device of claim 1 , wherein the mechanical restrictor further comprises an electrical unit, and the electrical unit exerts energy for regulating movement of the plunger.

15. A cartridge for an automatic injection device, comprising:
a space for receiving a drug container configured to include a pharmaceutical product and comprising a plunger that fits within the drug container; and
a movable element made of a shape memory alloy, having a first end and a second end, located within the drug container having a first longitudinal end and a second longitudinal end, where the second end of the movable element abuts the plunger and urges the plunger toward the second longitudinal end of the drug container by expanding based on shape memory properties of the movable element; and
a drive system comprising the movable element, a mechanical restrictor operatively coupled to the movable element, and a holding means adjacent to the first longitudinal end of the drug container, wherein
the movable element is comprised of a spring body,
the spring body comprises a plurality of openings,
the spring body comprises a plurality of interconnected arms formed of the shape memory alloy, having an upper surface and a lower surface,
the upper surface and the lower surface of each arm of the plurality of interconnected arms is substantially free from contact with the upper surface and the lower surface of all arms of the plurality of interconnected arms in both an extended state of the spring body and in a compressed state of the spring body,
the spring body is located within the drug container in both the extended state and the compressed state,
the holding means comprises a wire that couples with the movable element and holds the movable element in the compressed state preventing the movable element from moving to the extended state,
the mechanical restrictor comprises a ratchet mechanism that further regulates movement of the plunger from the compressed state to the extended state at a proscribed rate upon release of the holding means from the movable element, and
the drive system provides a small form factor which allows the automatic injection device to be compact.

16. The cartridge of claim 15 , wherein the plunger is configured to move in a linear direction from the first longitudinal end towards the second longitudinal end of the drug container in response to the spring body moving into the extended state.

17. An automatic injection device, comprising:
an insertion device configured to be inserted into a patient;
a drug container configure

Assignees

• Flex Ltd

Inventors

• Barmaimon Eyal
• Shtram Lior
• Cohen Nadav

Classifications

• F03G7/06145

  Springs · CPC title

• A61M5/31501 Primary

  Means for blocking or restricting the movement of the rod or piston (A61M5/5013 takes precedence) · CPC title

• A61M5/31576

  Constructional features or modes of drive mechanisms for piston rods · CPC title

• A61M5/44

  having means for cooling or heating the devices or media · CPC title

• A61M2205/0266

  Shape memory materials · CPC title