Transcutaneous analyte sensors, applicators therefor, and associated methods
The present embodiments relate generally to systems and methods for measuring an analyte in a host. More particularly, the present embodiments provide sensor applicators and methods of use with activation that implant the sensor, withdraw the insertion needle, engage the transmitter with the housing, and disengage the applicator from the housing. Systems and methods according to present principles allow for such steps to occur without significant loss of spring force, and without deleterious effects such as seal slingshotting.
1. An applicator for applying an on-skin sensor assembly to skin of a host, the applicator comprising:
an applicator housing operatively coupled to a disposable housing, the disposable housing being configured to receive an electronics unit, and the electronics unit being configured to generate analyte information based on a signal from a sensor;
an insertion assembly comprising an insertion member, the insertion member being configured to insert the sensor into the skin of the host;
a first drive assembly containing a first amount of stored energy, the first drive assembly being configured to drive the insertion member in a distal direction during a first phase and in a proximal direction during a second phase; and
a second drive assembly containing a second amount of stored energy, the second drive assembly being configured to drive the insertion member in the proximal direction,
wherein the first drive assembly is configured to activate the second drive assembly while driving the insertion member in the proximal direction during the second phase.
2. The applicator of claim 1 , wherein the drive assembly is self-reversing from the first phase to the second phase.
3. The applicator of claim 1 , wherein the first drive assembly is configured to drive the insertion member in the proximal direction after the insertion member reaches an inserted position.
4. The applicator of claim 1 , wherein the first drive assembly is configured to activate the second drive assembly in response to the first drive assembly reaching a trigger position during the second phase.
5. The applicator of claim 1 , further comprising a resistance member, the resistance member being operatively coupled to the insertion assembly during the first phase, wherein the second drive assembly is configured to decouple the resistance member from the insertion assembly during the second phase.
6. The applicator of claim 5 , wherein the second amount of stored energy is sufficient to decouple the resistance member from the insertion assembly.
7. The applicator of claim 1 , wherein the insertion assembly comprises a cannula.
8. The applicator of claim 7 , wherein a distal end of the insertion member extends distal of the cannula during the second phase.
9. The applicator of claim 7 , wherein the insertion member is configured to travel through the cannula during the first phase.
10. The applicator of claim 7 , wherein the resistance member is releasably coupled to a cannula.
11. The applicator of claim 7 , wherein the cannula is fixed relative to the disposable housing as the insertion member moves distally.
12. The applicator of claim 1 , wherein at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion.
13. The applicator of claim 1 , wherein at least one of the first drive assembly and the second drive assembly includes a scotch yoke, a crank slider, a barrel cam, or a rack and pinion.
14. The applicator of claim 1 , wherein at least one of the first drive assembly and the second drive assembly includes a spring.
15. The applicator of claim 1 , wherein at least one of the first drive assembly and the second drive assembly includes a torsion spring.
16. The applicator of claim 1 , wherein the second amount of stored energy is greater than the first amount of stored energy.
17. The applicator of claim 1 , further comprising a ratchet member configured to prevent backdriving of the first drive assembly.
18. A method of applying an on-skin sensor assembly to skin of a host, the method comprising:
providing an assembly comprising
an applicator housing operatively coupled to a disposable housing,
an insertion assembly comprising an insertion member,
a first drive assembly containing a first amount of stored energy, and
a second drive assembly containing a second amount of stored energy; and
activating a trigger of the assembly, wherein activating the trigger causes the first drive assembly to drive the insertion member in a distal direction during a first phase, wherein a sensor is inserted into the skin of the host, the first drive assembly to drive the insertion member in a proximal direction during a second phase, wherein the first drive assembly activates the second drive assembly while driving the insertion member in the proximal direction during the second phase, and
the second drive assembly to drive the insertion member in the proximal direction during the second phase.
19. The method of claim 18 , further comprising installing an electronics unit in the disposable housing, the electronics unit being configured to generate analyte information based on a signal from the sensor.
20. The method of claim 18 , wherein the assembly further comprises a resistance member coupled to the insertion assembly.
21. The method of claim 20 , wherein activating the trigger causes the second drive assembly to decouple the resistance member from the insertion assembly during the second phase.
22. The method of claim 20 , wherein the second amount of stored energy is sufficient to decouple the resistance member from the insertion assembly.
23. The method of claim 20 , wherein the resistance member comprises a seal.
24. The method of claim 18 , wherein the insertion assembly comprises a cannula.
25. The method of claim 18 , wherein the second amount of stored energy is greater than the first amount of stored energy.
26. The method of claim 18 , wherein at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion.
27. The method of claim 18 , wherein the first drive assembly activates the second drive assembly in response to the first drive assembly reaching a trigger position during the second phase.