Prosthetic wrist
Prostheses include a terminal device, a back-lock mechanism, a wrist, a limb-socket, and a harness system. The terminal device can be a five-fingered mechanical hand that provides a releasable adaptive grasp, and has independently flexible fingers. The limb socket can be 3D printed using a molded model of a remnant limb. The harness strap can encircle an unaffected limb and is coupled to the terminal device with a cable so that a user can control the terminal device. The harness system can include a 3D printed harness ring that couples to the cable.
1. A prosthetic wrist comprising:
a first piece couplable to a limb socket wearable on a remnant limb of a user;
a second piece couplable to a terminal unit;
one of the first piece and the second piece comprising a ball and another one of the first piece and the second piece comprising a wrist socket;
the wrist socket being removably couplable to the ball and selectively operable between:
an unlocked state where the ball is rotatable relative to the wrist socket in a plurality of different directions to permit flexion or extension of the terminal unit relative to the limb socket; and
a locked state where the ball is fixed relative to the wrist socket by a clamping force applied to the ball with the wrist socket to maintain a position of the terminal unit relative to the limb socket,
the wrist socket comprising a first wrist socket portion, a second wrist socket portion, a hinge that rotatably couples the first wrist socket portion to the second wrist socket portion, and a latch that is operable with an opposite limb of the user to apply the clamping force by decreasing a separation distance between the first wrist socket portion and the second wrist socket portion and release the clamping force by increasing the separation distance between the first wrist socket portion and the second wrist socket portion.
2. The wrist of claim 1 , wherein:
exterior surfaces of the ball define a convex shape; and
interior surfaces of the wrist socket define a concave shape operable to interface with the convex shape.
3. The wrist of claim 2 , wherein the clamping force establishes a friction fit between the convex shape and the concave shape.
4. The wrist of claim 3 , wherein one or both of the convex shape and the concave shape are configured to affect a frictional coefficient between the interior surfaces and the exterior surfaces.
5. The wrist of claim 3 , wherein one or both of:
the convex shape comprises a pattern of thin grooves; and
the concave shape comprises an elastomeric lining.
6. The wrist of claim 1 , wherein the latch is pivotally attached to the wrist socket so that the clamping force is adjustable by pivoting the latch toward the wrist with the opposite limb of the user and releasable by pivoting the latch away from the wrist with the opposite limb of the user.
7. The wrist of claim 1 , wherein:
the first wrist socket portion defines a first concave surface operable to interface with a first portion of the ball; and
the second wrist socket portion defines a second concave surface operable to interface with a second portion of the ball.
8. The wrist of claim 7 , wherein the latch is operable to cause:
the first concave surface of the first wrist socket portion to apply a first part of the clamping force to the first portion of the ball; and
the second concave surface of the second wrist socket portion to apply a second part of the clamping force to the second portion of the ball.
9. The wrist of claim 8 , wherein the latch is selectively operable to adjust the clamping force by changing a separation distance between the first concave surface of the first wrist socket portion and the second concave surface of the second wrist socket portion.
10. The wrist of claim 1 , comprising a first hole extending through the wrist socket and a second hole extending through the ball, the first and second holes being capable of directing a cable into the terminal unit through the wrist socket and the ball.
11. The wrist of claim 10 , wherein exterior surfaces of the ball define a semi-spherical convex shape and the second hole extends through an end face of the semi-spherical convex shape.
12. The wrist of claim 10 , comprising a plurality of connector holes extending through the ball at locations adjacent the second hole.
13. The wrist of claim 1 , wherein the first piece and the second piece are 3D printed structures.
14. The wrist of claim 11 , wherein the end face of the ball comprises a concave shape extending into the semi-spherical convex shape around the second hole.
15. A system comprising:
the prosthetic wrist of claim 10 ; and
the limb socket, in which the limb socket comprises a channel that extends through an interior of the limb socket and is capable of directing the cable through the interior of the limb socket and into the first hole of the wrist socket or the second hole of the ball.
16. The system of claim 15 , comprising:
the cable; and
a cable housing that passes along an exterior surface of the limb socket, enters the interior of the limb socket through the channel, and is capable of directing the cable into the interior of the limb socket.
17. The system of claim 16 , wherein the limb socket comprises a cable rotation guide capable of directing the cable housing into the interior of the limb socket and allowing a portion of the cable housing to pivot relative to the limb socket.
18. A system comprising:
the prosthetic wrist of claim 1 ; and
one or more of:
the limb socket;
the terminal unit;
a tricep brace; and
a harness.
19. The system of claim 17 , wherein the prosthetic wrist, the limb socket, and the terminal unit, the tricep brace, and the harness comprise 3D printed structures.