Rotationally biased insertion mechanism for a drug delivery pump
An insertion mechanism for a drug pump includes an insertion mechanism housing; a sleeve; a rotational biasing member initially held in an energized state; a retraction biasing member and a hub connected to a proximal end of a needle, wherein the retraction biasing member is held initially in an energized state between the hub and the sleeve. The needle is inserted into a target tissue by the rotational biasing member and interaction between the hub and housing. Retraction of the needle is caused by decompressing or de-energizing of the retraction biasing member. A drug delivery pump includes an activation mechanism, a drive mechanism, a sterile access connection, and the insertion mechanism. Assembly and operation methods are provided.
1. An insertion mechanism for a drug delivery device, the insertion mechanism comprising:
a housing;
a rotational biasing member coupled with the housing and initially held in an energized state, the rotational biasing member being configured to rotate the housing as the rotational biasing member de-energizes;
an insertion member disposed at least partially within the housing and having a proximal end and a distal end;
a hub coupled with the insertion member, the hub and the insertion member being configured to move linearly between an initial position and an insertion position;
a retraction biasing member coupled with the hub and configured to move the hub and the insertion member from the insertion position toward the initial position as the retraction biasing member de-energizes; and
wherein rotation of the housing caused by de-energizing of the rotational biasing member causes the hub and the insertion member to move linearly from the initial position to the insertion position and subsequent de-energizing of the retraction biasing member causes the hub and the insertion member to move from the insertion position toward the initial position.
2. The insertion mechanism of claim 1 , wherein the rotational biasing member comprises a torsional spring.
3. The insertion mechanism of claim 1 , wherein the retraction biasing member comprises a compression spring.
4. The insertion mechanism of claim 1 , wherein the hub is disposed at least partially within the housing.
5. The insertion mechanism of claim 1 , wherein the retraction biasing member is disposed between the hub and an axially-stationary element.
6. The insertion mechanism of claim 5 , wherein the axially-stationary element comprises a sleeve.
7. The insertion mechanism of claim 6 , wherein the sleeve is disposed at least partially within the housing.
8. The insertion mechanism of claim 6 , wherein the housing includes a guide surface and the hub includes an outwardly-extending follower configured to slidably engage the guide surface as the housing rotates, and wherein the outwardly-extending follower is at least partially arranged in an axially-extending recess formed in the sleeve such that the hub and the sleeve are rotationally fixed relative to one another.
9. The insertion mechanism of claim 1 , wherein the housing includes at least one circumferentially-ramped guide surface, the circumferentially-ramped guide surface including an at least partially radially disposed surface having a component that extends in both an axial direction and n circumferential direction.
10. The insertion mechanism of claim 9 , wherein the hub includes at least one follower configured and disposed to follow the circumferentially-ramped guide surface as the housing rotates to axially translate the hub between the initial position and the insertion position.
11. The insertion mechanism of claim 10 , wherein the housing includes at least one axially-extending slot, the follower being configured to engage the axially- extending slot to allow the hub to move from the insertion position toward the initial position.
12. The insertion mechanism of claim 1 , wherein secondary rotation of the housing caused by de-energizing of the rotational biasing member subsequent to insertion of the insertion member allows for de-energizing of the retraction biasing member.
13. The insertion mechanism of claim 1 , wherein movement of the hub from the initial position to the insertion position energizes the retraction biasing member.
14. The insertion mechanism of claim 1 , wherein the insertion member comprises a needle.
15. The insertion mechanism of claim 14 , wherein the needle has a hollow interior.