Sensor assembly and medical device incorporating same

• US 8,968,245 B2
• Filed: 06/21/2013
• Issued: 03/03/2015
• Est. Priority Date: 10/20/2010
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Bazargan, Afshin, Vazquez, Pablo, Kow, Hsiao-Yu S.
• Primary Examiner(s): FLICK, JASON E
• Application Number:
  US13/924,382
• Publication Number:
  US 20130283934A1
• Time in Patent Office: 620 Days
• Field of Search: 604/151
• US Class Current: 604/151
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: G01L 1/04 by measuring elastic deformation of gauges, e.g. of springs
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 5/12 for measuring axial thrust in a rotary shaft, e.g. of propulsion plants

Abstract

Apparatus are provided for sensor assemblies and related medical devices. An embodiment of a sensor assembly includes a rigid structure and a beam structure having an outer portion in contact with the rigid structure and an inner portion. The beam structure includes one or more beams extending between the outer portion and the inner portion of the beam structure and a cantilevered portion extending from the inner portion to inhibit displacement of the inner portion toward the rigid structure. Each beam has a sensing element disposed thereon.

Claims

1. A sensor assembly, comprising:

a rigid structure; and

a beam structure having an outer portion in contact with a surface of the rigid structure and an inner portion, the beam structure comprising;

one or more beams extending between the outer portion and the inner portion of the beam structure, each beam comprising an arm portion between the outer portion and an end portion forming the inner portion, the arm portion having a sensing element disposed thereon, wherein a separation distance between the inner portion and the surface of the rigid structure is less than a separation distance between the arm portion and the rigid structure; and

a cantilevered portion extending from the inner portion and dampening displacement of the inner portion toward the surface of the rigid structure when a force applied to the sensor assembly is greater than a threshold value.

2. The sensor assembly of claim 1, wherein the cantilevered portion contacts the surface of the rigid structure to inhibit displacement of the inner portion when the force applied to the sensor assembly is greater than the threshold value.

3. The sensor assembly of claim 1, wherein the cantilevered portion contacts the surface of the rigid structure before the inner portion contacts the surface of the rigid structure when the force applied to the sensor assembly is greater than the threshold value.

4. The sensor assembly of claim 1, wherein an airgap separating the cantilevered portion from the surface of the rigid structure is less than the separation distance between the inner portion and the surface of the rigid structure.

5. The sensor assembly of claim 1, further comprising a dampening material affixed to the cantilevered portion, the dampening material contacting the rigid structure to dampen displacement of the inner portion.

6. The sensor assembly of claim 5, wherein the dampening material contacts the surface of the rigid structure before the inner portion contacts the surface of the rigid structure when the force applied to the sensor assembly is greater than the threshold value.

7. The sensor assembly of claim 5, wherein an airgap separating the dampening material from the surface of the rigid structure is less than the separation distance between the inner portion and the surface of the rigid structure.

8. The sensor assembly of claim 1, the beam structure comprising a plurality of beams, wherein the end portions of the plurality of beams are integral and form the inner portion.

9. The sensor assembly of claim 8, wherein the arm portions of the plurality of beams and the cantilevered portion move in unison with the inner portion with respect to the outer portion.

10. The sensor assembly of claim 8, wherein the cantilevered portion is disposed between arm portions of adjacent beams of the plurality of beams.

11. The sensor assembly of claim 1, further comprising a loading element coupled to the inner portion, the loading element to displace the inner portion towards the rigid structure in response to a compressive force applied to the loading element.

12. The sensor assembly of claim 1, wherein the sensing element comprises a strain gauge having a glass coating affixing the strain gauge to the beam.

13. The sensor assembly of claim 1, wherein the cantilevered portion extends radially outward from the inner portion and is freestanding with respect to the outer portion.

14. The sensor assembly of claim 1, wherein the outer portion is affixed to the surface of the rigid structure.

15. The sensor assembly of claim 2, wherein the cantilevered portion does not contact the surface of the rigid structure when the force applied to the sensor assembly is within an intended measurement range for the sensor assembly.

16. A portable medical device, comprising:

a sliding member;

a drive system to displace the sliding member in a first direction; and

a sensor assembly coupled to the drive system to measure force provided by the drive system to displace the sliding member in the first direction, the sensor assembly comprising;

a back plate;

a beam structure having an outer portion in contact with the back plate and an inner portion, the beam structure comprising;

a beam comprising an arm portion extending between the outer portion and the inner portion of the beam structure, wherein a separation distance between the inner portion and the back plate is less than a separation distance between the arm portion and the back plate; and

a cantilever portion extending from the inner portion to dampen displacement of the inner portion toward the back plate when force applied to the sensor assembly is greater than a threshold value; and

a sensing element disposed on the beam.

17. The portable medical device of claim 16, wherein the cantilever portion contacts the back plate when the force applied to the sensor assembly is greater than the threshold value.

18. The portable medical device of claim 16, wherein the cantilever portion includes a dampening material to contact the back plate when the force applied to the sensor assembly is greater than the threshold value.

19. The portable medical device of claim 16, wherein the sensor assembly includes a loading element coupled to the inner portion, the loading element to displace the inner portion towards the back plate in response to the force applied to the sensor assembly.

20. The portable medical device of claim 19, further comprising a capping member in contact with the loading element to deflect the beam towards the back plate in response to the force provided by the drive system in the first direction.