SELF-ADJUSTING PRELOAD FOR MEMORY ALLOY WIRE

• US 20150175321A1
• Filed: 03/05/2015
• Published: 06/25/2015
• Est. Priority Date: 01/24/2011
• Status: Active Grant

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Inventors: WEBER, FRANK DEAN, POTAKOWSKYJ, CHRISTOPH, BAYER, ERNST
• Granted Patent: US 10,029,829 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B65D 2251/10 Details of hinged closures
• CPC Class Codes: B65D 2251/1066 Actuating means
• CPC Class Codes: B65D 2543/00194 square or rectangular
• CPC Class Codes: B65D 43/164 and connected by interfitting hinge elements integrally with the container and the lid formed respectively
• CPC Class Codes: B65D 43/26 Mechanisms for opening or closing, e.g. pedal-operated for refuse receptacles B65F1/1623
• CPC Class Codes: E05B 47/0009 with thermo-electric actuators, e.g. heated bimetals
• CPC Class Codes: E05B 65/006 for covers or panels for manholes E02D29/1427; for holes enabling access to installations in buildings E04F19/08; for pressure vessels F16J13/00
• CPC Class Codes: E05C 3/30 in the form of a hook hook-like fastenings E05C19/10; locks for sliding wings with pivoting bolts E05B65/0811, E05B65/0835
• CPC Class Codes: F03G 7/0614 using shape memory elements
• CPC Class Codes: F03G 7/065 using a shape memory element
• CPC Class Codes: Y10T 292/1047 Closure
• CPC Class Codes: Y10T 292/1052 Operating means
• CPC Class Codes: Y10T 292/68 Keepers

Abstract

A preload mechanism for a memory alloy wire actuator is disclosed that includes a rotating element configured to rotate about a pivot. The rotating element has a first contact point that is configured to couple to the memory alloy wire actuator such that contraction of the memory alloy wire actuator displaces the first contact point such that the rotating element rotates from a first position to a second position. The preload mechanism also includes a bias element with a first end that is coupled to a second contact point of the rotating element and a second end configured to be pinned relative to the pivot. The bias element has a line of action extending from the second end through the first end. The line of action has an offset distance that is the minimum distance between the line of action and the pivot. The offset distance has a first value when the rotating element is in the first position and a second value when the rotating element is the second position, the second value being smaller than the first value.

Claims

1. A preload mechanism for a memory alloy wire actuator, the preload mechanism comprising:

a rotating element having first and second contact points and a pivot, the rotating element configured to rotate about the pivot, wherein the first contact point is configured to couple to the memory alloy wire actuator such that contraction of the memory alloy wire actuator displaces the first contact point such that the rotating element rotates from a first position to a second position; and

a bias element having first and second ends, the first end coupled to the second contact point of the rotating element and the second end configured to be pinned relative to the pivot, wherein the bias element has a line of action extending from the second end through the first end,

wherein the preload mechanism comprises an offset distance that is the minimum distance between the line of action and the pivot, the offset distance having a first value when the rotating element is in the first position and a second value when the rotating element is the second position.

2. The preload mechanism of claim 1, wherein the bias element comprises a spring element having a spring constant.

3. The preload mechanism of claim 2, wherein the bias element is selected from the group consisting of a torsion spring, a linear coil compression spring, a diaphragm spring, an elastic tension element, a gas spring, and a constant force mechanism.

4. The preload mechanism of claim 1, wherein the rotating element is configured such that a translational acceleration of the preload mechanism does not generate a torsional moment on the rotating element about the pivot.

5. The preload mechanism of claim 1, further comprising a mass fixedly coupled to a side of the rotating element about the pivot and configured to place a center of gravity of the rotating element at the pivot.

6. The preload mechanism of claim 1, wherein the first value of the offset distance is greater than the second value of the offset distance.

7. The preload mechanism of claim 1, wherein a torque applied to the rotating element by the bias element in the first position is lower than an opposite torque applied to the rotating element by the bias element in the second position.

8. The preload mechanism of claim 1, wherein the first contact point is a knife edge coupling the rotating element to the memory alloy wire actuator, the memory alloy wire actuator comprising a memory alloy wire wrapped around a capstan forming the knife edge to receive an arm of the rotating element.

9. The preload mechanism of claim 8, wherein the capstan is coupled to a latch release mechanism configured to open a lidded container.

10. The preload mechanism of claim 9, wherein the lidded container is configured to receive an electronic signal to actuate the memory alloy actuator.

11. The preload mechanism of claim 10, wherein the lidded container is one of a plurality of lidded containers in an Automated Dispensing Machine (ADM), the ADM comprising a cabinet to store the plurality of lidded containers, an electronic circuitry to provide the electronic signal to at least one of the lidded containers, and a controller to provide commands to the electronic circuitry and determine which lidded container receives the electronic signal.

12. The preload mechanism of claim 11, wherein at least one of the plurality of lidded containers is integrally formed into the structure of the cabinet.

13. The preload mechanism of claim 11, wherein at least one of the plurality of lidded containers is detachable from the structure of the cabinet.

14. The preload mechanism of claim 1, wherein the pivot and the second end of the bias element are pinned to a body of a lidded container.

15. The preload mechanism of claim 1, wherein the rotating element is coupled to the memory alloy wire actuator such that the displacement of the first contact point is substantially parallel to the contraction of two parallel portions of the memory alloy wire.

16. A method for opening a lidded container with a preload mechanism comprising:

contracting a memory alloy wire in a latch release mechanism, the memory alloy wire coupled to a capstan in contact with a rotating element having a pivot,

wherein the contracting of the memory alloy causes the rotating element to rotate about the pivot from a first position to a second position against a restoring force provided by a biasing element having at least one end pinned relative to the pivot;

releasing a lid in the lidded container; and

providing access to a medication for a patient from the lidded container.

17. The method of claim 16, wherein contracting the memory alloy wire comprises heating the memory alloy wire such that a crystalline structure of the material forming the memory alloy wire changes from a first form to a second form.

18. The method of claim 16, wherein heating a memory alloy wire comprises transmitting a current through the memory alloy wire.

19. The method of claim 16, further comprising closing the lid in the lidded container by pressing a latch hook in the lid onto a latch hook in a latch lever of the latch release mechanism when the memory alloy wire is cold.

20. The method of claim 16, further comprising:

opening a drawer of an Automated Dispensing Machine (ADM); and

electronically coupling the lidded container with a mating connector in one of a plurality of locations in the drawer of the ADM.