Prosthetic partial fingers
Various embodiments of the present invention generally relate to prosthetic partial finger designs that can mimic the last two joints of the finger. Some embodiments include a proximal phalange, a distal phalange coupled to the proximal phalange, and a knuckle track (e.g., formed in an arc). The knuckle track can be moveably coupled to the proximal phalange an may include multiple teeth formed on which the proximal phalange slides along. A ratcheting mechanism can contact the multiple teeth to allow sliding in only a first direction while the ratcheting mechanism is engaged. Some embodiments include a release mechanism (e.g., a button) configured to disengage the ratcheting mechanism from the multiple teeth to allow the distal phalange to slide in a second direction. In some embodiments, the device may include a spring-back capability that automatically extends the finger after reaching full finger flexion, enabling one-handed use.
1. A prosthetic finger, comprising:
a knuckle defining:
an arc and configured to attach to a prosthetic socket; and
an aperture;
a first phalange, comprising:
a first end coupled to the knuckle; and
a second end, the first phalange configured to:
move with respect to the knuckle in a flexion direction; and
move with respect to the knuckle in an extension direction;
a second phalange corresponding to a distal phalange, coupled to the first phalange and configured to rotate about the second end of the first phalange;
a link bar, comprising:
a first end rotationally coupled to the aperture; and
a second end coupled to the second phalange and configured to rotate the second phalange about the second end of the first phalange when the first phalange moves in the flexion direction; and
a locking mechanism, comprising:
a first component coupled to the first phalange;
a second component coupled to the knuckle, configured to releasably engage with the first component, and configured to prevent the first phalange from moving in the extension direction when the first component is engaged with the second component; and
a release button configured to disengage the first component from the second component, thereby allowing the first phalange to move in the extension direction.
2. The prosthetic finger of claim 1 , further comprising a spring, wherein:
the spring is configured to bias the first phalange to move in the extension direction; and
the first end of the link bar is configured to rotate with respect to the knuckle to cause the second phalange to extend when the first phalange moves in the extension direction.
3. The prosthetic finger of claim 2 , wherein the spring causes the first phalange to fully extend when the release button is engaged.
4. The prosthetic finger of claim 2 , further comprising a stop configured to set full flexion of the prosthetic finger, wherein:
the locking mechanism further comprises a disengagement feature; and
the spring causes the first phalange to fully extend when the disengagement feature contacts the locking mechanism.
5. The prosthetic finger of claim 1 , wherein:
the first component comprises a ratchet; and
the second component comprises one or more teeth.
6. The prosthetic finger of claim 5 , wherein the ratchet is connected to the first phalange and slides along the one or more teeth when the first phalange is moved in the flexion or extension directions.
7. The prosthetic finger of claim 1 , wherein the first phalange corresponds to a medial phalange of a hand.
8. A prosthetic finger comprising:
a knuckle configured to interface with a prosthetic socket;
a first phalange comprising:
a first end coupled to the knuckle; and
a second end opposite the first end, the first phalange configured to:
move relative to the knuckle in a first manner corresponding to flexion of the prosthetic finger; and
move relative to the knuckle in a second manner corresponding to extension of the prosthetic finger;
a distal phalange, coupled to the first phalange and configured to rotate about the second end of the first phalange;
a link bar extending from the knuckle and to the distal phalange, comprising:
a first end rotationally connected to the knuckle; and
a second end connected to the distal phalange, the link bar configured to couple movement of the first phalange to the distal phalange such that, when the first phalange moves relative to the knuckle, the distal phalange rotates about the second end of the first phalange; and
a locking mechanism coupled to the first phalange and configured to:
in a first state, prevent movement of the first phalange in the second manner; and
in a second state, allow movement of the first phalange in the second manner.
9. The prosthetic finger of claim 8 , wherein:
the locking mechanism is configured to operate in the first state when not being engaged by a user; and
the locking mechanism is configured to operate in the second state when engaged by the user.
10. The prosthetic finger of claim 9 , wherein the locking mechanism comprises a button that, when pressed, causes the locking mechanism to transition from the first state to the second state.
11. The prosthetic finger of claim 8 , further comprising a torsion spring configured to move the first phalange in the second manner when the locking mechanism is in the second state.
12. The prosthetic finger of claim 8 , wherein the locking mechanism comprises:
a set of teeth; and
a ratchet configured to engage with the set of teeth when the locking mechanism is operating in the first state.
13. The prosthetic finger of claim 12 , wherein the ratchet is connected to the first phalange.
14. The prosthetic finger of claim 8 , wherein:
the first end of the link bar is configured to pivot with respect to the knuckle; and
the second end of the link bar is configured to pivot with respect to the distal phalange.
15. The prosthetic finger of claim 14 , wherein:
the knuckle comprises an aperture; and
the aperture is used to connect the first end of the link bar to the knuckle.
16. A prosthetic finger comprising:
a knuckle configured to interface with a prosthetic socket;
a first phalange corresponding to a medial phalange, comprising:
a first end coupled to the knuckle; and
a second end opposite the first end, and configured to:
move in a first direction corresponding to flexion of the prosthetic finger; and
move in a second direction corresponding to extension of the prosthetic finger;
a second phalange corresponding to a distal phalange coupled to the first phalange and configured to rotate about the second end of the first phalange;
a link bar, comprising:
a first coupling to the knuckle that is configured to allow the link bar to rotate relative to the knuckle; and
a second coupling to the second phalange that is configured to cause the distal phalange to rotate about the second end of the first phalange when the first phalange moves with respect to the knuckle; and
a spring configured to bias the prosthetic finger to move in the second direction.
17. The prosthetic finger of claim 16 , further comprising a locking mechanism, wherein:
the locking mechanism prevents movement of the first phalange in the second direction when operating in a first state; and
the locking mechanism allows the spring to move the first phalange in the second direction when operating in a second state.
18. The prosthetic finger of claim 17 , wherein the locking mechanism comprises:
a stop that is configured to set full flexion of the prosthetic finger; and
a disengagement feature that is configured to switch the locking mechanism from the first state to the second state in response to contacting the stop.
19. The prosthetic finger of claim 18 , wherein:
movement of the first phalange in the first direction causes the disengagement feature to contact the stop; and
in response to the disengagement feature contacting the stop, the spring causes the prosthetic finger to fully extend.