SMC integrated bi-stable strips for remote actuation

Patent metadata

Field	Value
Publication number	US-11460010-B1
Application number	US-202117216951-A
Country	US
Kind code	B1
Filing date	Mar 30, 2021
Priority date	Mar 30, 2021
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A remote actuator includes one or more bi-stable strips with at least one shape memory composite (SMC) spring connected to each bi-stable strip. The SMC spring includes a thermoplastic and an electrical and/or thermal conductor for transforming the length of the SMC spring upon heating. The contraction of the SMC spring transforms the bi-stable strip from its coiled stable state to its elongated stable state. The displacement of the SMC spring can be amplified by a simple machine included in the remote actuator. The remote actuator can include a shape memory alloy (SMA) strip for transforming the bi-stable strip from its elongated stable state to it curved stable state upon heating. Heating can be by Joule heating or from an adjacent heat source.

First claim

What is claimed is:

1. A remote actuator comprising:
at least one bi-stable strip with two passive shapes;
at least one shape memory composite (SMC) spring attached to both ends of each of the at least one bi-stable strip; and
a heat source configured for heating the SMC spring.

2. The remote actuator according to claim 1 , wherein the SMC spring comprises at least one twisted or coiled filament comprising a thermoplastic and a conductor, where the conductor is an electrical conductor and/or a thermal conductor.

3. The remote actuator according to claim 2 , wherein the thermoplastic comprises nylon 6,6, nylon 6, nylon 12, or ultra-high-molecular-weight polyethylene (UHMWPE).

4. The remote actuator according to claim 3 , wherein the conductor comprises a filler within a matrix comprising the thermoplastic.

5. The remote actuator according to claim 4 , wherein the filler is selected from a multiplicity of carbon nanotubes (CNTs), carbon fibers, graphene flakes, metal fibers, metal flakes, and any combination thereof.

6. The remote actuator according to claim 2 , wherein the conductor comprises a metal coating on the twisted or coiled filament.

7. The remote actuator according to claim 2 , wherein the conductor comprises a metal wire co-twisted or coiled with the twisted or coiled filament.

8. The remote actuator according to claim 2 , wherein the heat source is the electrical conductor for Joule heating.

9. The remote actuator according to claim 1 , further comprising a shape memory alloy (SMA) strip.

10. The remote actuator according to claim 9 , wherein the SMA strip is a nitinol strip.

11. The remote actuator according to claim 9 , wherein a length of the SMA strip is perpendicular to a long axis of the bi-stable strip, and a length the SMC spring is parallel to the long axis of the bi-stable strip.

12. The remote actuator according to claim 1 , further comprising at least one simple machine coupled to the SMC spring.

13. The remote actuator according to claim 12 , wherein the simple machine comprises at least one axle, dowel, lever, gear, wheel, or screw.

14. A method of remote actuation, comprising:
providing a remote actuator, comprising;
at least one bi-stable strip with two passive shapes; and
at least one shape memory composite (SMC) spring attached to both ends of each of the at least one bi-stable strip, wherein the SMC spring comprises at least one twisted or coiled filament comprising a thermoplastic and a conductor, where the conductor is an electrical conductor and/or a thermal conductor;

heating the SMC spring to contract the SMC spring; and
applying a contractive force from the SMC spring on the bi-stable strip in a curved stable state for elongating the bi-stable strip to an elongated stable state.

15. The method according to claim 14 , wherein heating comprises switching an electric switch for passing a current through the electrical conductor of the SMC spring.

16. The method according to claim 14 , wherein the remote actuator further comprises a shape memory alloy (SMA) strip.

17. The method according to claim 16 , further comprising:
activating the SMA strip by applying a current to the SMA strip to change to a memory shape; and
applying a force from the SMA strip to the bi-stable strip for contracting the bi-stable strip to a curved stable state.

18. The method according to claim 14 , wherein the remote actuator further comprises a simple machine coupled to the SMC spring, and the method comprises amplifying a displacement of the SMC spring by using the simple machine.

Assignees

• Toyota Eng & Mfg North America

Inventors

• Tsuruta Ryohei
• Pinkelman Brian J
• Gandhi Umesh N
• Gilmore Paul A
• Smith Mark E
• Smith Eric D
• Panwar Shardul Singh

Classifications

• F03G7/06145

  Springs · CPC title

• F03G7/0613 Primary

  using layers of different materials joined together, e.g. bimetals · CPC title

• F03G7/0614 Primary

  using shape memory elements · CPC title

• F03G7/065 Primary

  using a shape memory element · CPC title