Drive mechanism for a needle insertion arrangement

1. Drive mechanism for a needle insertion arrangement, the drive mechanism comprising:

an actuator coupled to a parallel linkage adapted to convert a linear movement of the actuator in a longitudinal direction (L) to a linear movement of a cross beam in transverse direction (T) substantially at right angles with respect to the longitudinal direction (L), wherein the linkage comprises:

a connecting rod coupled to the actuator, the connecting rod comprising a transversal engagement bar for engaging a drive rod of the actuator in such a manner that a position of the drive rod relative the engagement bar is fixed with respect to movements in the longitudinal direction (L) while the drive rod is allowed to slide along the engagement bar in the transverse direction (T);

at least one cross beam; and

at least two links, at least one of the links pivoted at one end in the connecting rod and at another end in a fixed anchor point, and at least another one of the links pivoted at one end in the cross beam and at another end in the connecting rod.

2. Drive mechanism according to claim 1 , wherein the cross beam is arranged as a needle retainer arranged to retain an injection needle and to be moved between a retracted position (RP) and an extended position (EP).

3. Drive mechanism according to claim 2 , further comprising a linear guide for guiding the needle retainer in the transverse direction (T).

4. Drive mechanism according to claim 1 , wherein the linkage comprises at least four links, at least two of the at least four links pivoted at one end in respective pivots in the connecting rod and at another end in respective pivots on fixed anchor points, and at least two others of the at least four links pivoted at one end in respective pivots in the cross beam and at another end in respective pivots in the connecting rod.

5. Drive mechanism according to claim 4 , wherein the links pivoted in the fixed anchor points are arranged in parallel and wherein the links pivoted in the cross beam are arranged in parallel.

6. Drive mechanism according to claim 4 , wherein an imaginary line connecting the pivots in the fixed anchor points, the cross beam and the connecting rod are arranged in parallel.

7. Drive mechanism according to claim 1 , wherein the actuator is fixed in position relative the at least one pivot in the fixed anchor point.

8. Drive mechanism according to claim 1 , wherein the actuator is arranged as an electrical actuator.

9. Drive mechanism according to claim 8 , wherein the electrical actuator is arranged as a piezo actuator.

10. Insertion arrangement for moving an injection needle between a retracted position (RP) and an extended position (EP), the insertion arrangement comprising:

a disposable unit comprising a needle base to which the needle is fixed; and

a drive mechanism comprising:

an actuator coupled to a parallel linkage adapted to convert a linear movement of the actuator in a longitudinal direction (L) to a linear movement of a cross beam in transverse direction (T) substantially at right angles with respect to the longitudinal direction (L), wherein the linkage comprises:

a connecting rod coupled to the actuator, the connecting rod comprising a transversal engagement bar for engaging a drive rod of the actuator in such a manner that a position of the drive rod relative the engagement bar is fixed with respect to movements in the longitudinal direction (L) while the drive rod is allowed to slide along the engagement bar in the transverse direction (T);

at least one cross beam; and

at least two links, at least one of the links pivoted at one end in the connecting rod and at another end in a fixed anchor point, and at least another one of the links pivoted at one end in the cross beam and at another end in the connecting rod,

wherein a needle retainer is adapted to retain the needle base.

11. The insertion arrangement according to claim 10 , wherein the cross beam is arranged as the needle retainer arranged to retain an injection needle and to be moved between a retracted position (RP) and an extended position (EP).

12. The insertion arrangement according to claim 11 , the drive mechanism further comprising a linear guide for guiding the needle retainer in the transverse direction (T).

13. The insertion arrangement according to claim 10 , wherein the linkage comprises at least four links, at least two of the at least four links pivoted at one end in respective pivots in the connecting rod and at another end in respective pivots on fixed anchor points, and at least two others of the at least four links pivoted at one end in respective pivots in the cross beam and at another end in respective pivots in the connecting rod.

14. The insertion arrangement according to claim 13 , wherein the links pivoted in the fixed anchor points are arranged in parallel and wherein the links pivoted in the cross beam are arranged in parallel.

15. The insertion arrangement according to claim 13 , wherein an imaginary line connecting the pivots in the fixed anchor points, the cross beam and the connecting rod are arranged in parallel.

16. The insertion arrangement according to claim 10 , wherein the actuator is fixed in position relative the at least one pivot in the fixed anchor point.

17. The insertion arrangement according to claim 10 , wherein the actuator is arranged as an electrical actuator.