TWO STAGE ACTUATOR FOR POWERED MOBILITITY ASSISTANCE DEVICES WITH ELECTRICAL ISOLATION

1 . An actuator assembly comprising:

a motor; and

a transmission system that provides a speed reduction of a motor speed to an output speed;

wherein:

the transmission system includes a non-conductive material layer that electrically isolates the motor from an output of the transmission system;

the transmission system comprises a first stage of speed reduction connected to an output shaft of the motor for providing a speed reduction of the motor output, and a second stage of speed reduction linked to an output of the first stage of speed reduction for providing a speed reduction from the output of the first stage to the output speed, the first stage of speed reduction comprising a first rotating member attached to the output shaft of the motor that transmits power to a second rotating member;

the second rotating member comprises an inner ring and an outer ring made of an electrically conductive material and the non-conductive material layer is located between the inner ring and the outer ring; and

the inner ring includes a first set of internal ridges that extends radially outward onto which the non-conductive material layer is disposed, and the outer ring includes a second set of internal ridges that extends radially inward onto which the non-conductive material layer is disposed.

2 . The actuator assembly of claim 1 , wherein the first and second sets of internal ridges are interspersed relative to each other so as to form cooperating opposing teeth.

3 . The actuator assembly of claim 1 , wherein the non-conductive material layer is over-molded onto the inner and outer rings.

4 - 5 . (canceled)

6 . The actuator assembly of claim 1 , wherein the non-conductive material layer is made of plastic.

7 . The actuator assembly of claim 1 , wherein:

the second stage of speed reduction comprises a shaft that is commonly attached to the second rotating member and a third rotating member that transmits power to a fourth rotating member by a transmission member;

the fourth rotating member has a diameter larger than a diameter of the third rotating member to provide the second stage of speed reduction; and

an output wheel is fixed to the fourth rotating member to provide the output of the transmission system.

8 . The actuator assembly of claim 7 , wherein third and fourth rotating members are sprockets, and the transmission member is a roller chain that interacts with the teeth of the sprockets as the sprockets rotate.

9 . The actuator assembly of any of claim 7 , wherein the output wheel includes a magnetic coupling comprising a plurality of magnetic elements that are configured to magnetically couple with an opposing magnetic coupling of a driven component.

10 . The actuator assembly of claim 9 , wherein the magnetic coupling comprises a plurality of recessed pockets, and at least one of the recessed pockets includes a respective one of the plurality of magnetic elements located at a bottom of the recessed pocket.

11 . The actuator assembly of claim 9 , wherein each recessed pocket includes a mating surface extending from an outer surface the output wheel toward a bottom of the recessed pocket.

12 . The actuator assembly of claim 11 , wherein the mating surface is a tapered mating surface.

13 . The actuator assembly of claim 10 , wherein each recessed pocket includes a respective one of the plurality of magnetic elements.

14 . (canceled)

15 . An orthotic device comprising:

a knee-ankle-foot orthosis (KAFO) brace; and

an actuator assembly according to claim 1 and a driven joint member;

wherein the actuator assembly is attached to a thigh support of the KAFO brace, and the driven joint member acts a knee joint of the KAFO brace.

16 . An orthotic device comprising:

a hip-knee-ankle-foot orthosis (HKAFO) brace;

a first actuator assembly according to claim 1 and a first driven joint member;

wherein the first actuator assembly is attached to a thigh support of the HKAFO brace, and the first driven joint member acts a knee joint of the HKAFO brace; and/or

a second actuator assembly according to claim 1 and a second driven joint member;

wherein the second actuator assembly is attached to a torso support of the HKAFO brace, and the second driven joint member acts a hip joint of the HKAFO brace.

17 . A rotating member comprising:

an inner ring and an outer ring made of an electrically conductive material; and

a non-conductive material layer that is located between the inner ring and the outer ring, wherein the non-conductive material layer electrically isolates the inner ring from the outer ring.

18 . The rotating member of claim 17 , wherein the inner ring includes a first set of internal ridges that extends radially outward onto which the non-conductive material layer is disposed, and the outer ring includes a second set of internal ridges that extends radially inward onto which the non-conductive material layer is disposed.

19 . The rotating member of claim 18 , wherein the first and second sets of internal ridges are interspersed relative to each other so as to form cooperating opposing teeth.

20 . The rotating member of claim 17 , wherein the non-conductive material layer is over-molded onto the inner and outer rings.

21 . The rotating member of claim 17 , further comprising gear teeth located on an outer diameter of the rotating member.

22 . The rotating member of claim 17 , wherein the rotating member is a helical gear.

23 . The rotating member of claim 17 , wherein the non-conductive material layer is made of plastic.

24 - 27 . (canceled)