Bistable elastomeric actuator
View Patent ↗Elastomeric actuators and methods of making the same are provided herein. In some examples, an actuator includes a body comprising a plurality of pairs of frustums, wherein the body is configured to receive a fluid to extend the actuator and to remove the fluid to contract the actuator. In some examples, each pair of frustums includes two thin frustum shells sharing a common base circle diameter.
1. An actuator, comprising:
a body comprising a plurality of pairs of frustums,
wherein the body is configured to receive a fluid to extend the actuator and to remove the fluid to contract the actuator,
wherein each pair of frustums comprises two thin frustum shells sharing a common base circle diameter, and
wherein one of the thin frustum shells is configured with a first base angle and the other of the thin frustum shells is configured with a second base angle that is smaller than the first base angle.
2. The actuator of claim 1 , wherein the first base angle is about 55 degrees.
3. The actuator of claim 2 , wherein the second base angle is about 40 degrees.
4. The actuator of claim 2 , wherein the two thin frustum shells are coupled by a soft folding hinge.
5. The actuator of claim 4 , wherein the soft folding hinge comprises an elastomer.
6. The actuator of claim 2 , wherein a portion of the thin frustum shell configured with the large base angle is shaved off and replaced by an elastomer.
7. The actuator of claim 1 , wherein the body further comprises an elastomer.
8. The actuator of claim 7 , wherein the elastomer comprises silicone.
9. The actuator of claim 1 , wherein each frustum is threaded with yarn.
10. The actuator of claim 1 , wherein the plurality of pairs of frustums comprises a thermoplastic polymer.
11. The actuator of claim 10 , wherein the thermoplastic polymer comprises polyethylene terephthalate (PET).
12. A method for forming an actuator, the method comprising:
folding a thermoplastic polymer sheet into a frustum shape;
threading yarn around the thermoplastic polymer sheet;
molding, in a first mold, a plurality of thermoplastic polymer frustums with an elastomer to form a plurality of elastomer frustums with embedded thermoplastic polymer;
molding, in a second mold with a soft thermoplastic polyurethane inner mold, the plurality of elastomer frustums to form an actuator shape;
demolding the actuator; and
inserting a thermoplastic polymer support shell into the actuator.
13. The method of claim 12 , wherein the thermoplastic polymer comprises polyethylene terephthalate (PET).
14. The method of claim 12 , wherein the plurality of thermoplastic polymer frustums comprises at least one thermoplastic polymer frustum with a large base angle and at least one thermoplastic polymer frustum with a small base angle.
15. The method of claim 12 , wherein the elastomer comprises silicone.