Prosthetic Partial Fingers

Abstract

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.

What is claimed is: 
     
         1 . A prosthetic finger comprising:
 a knuckle defining an arc and configured to attach to a prosthetic socket;   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 first direction corresponding to flexion of the prosthetic finger; and 
 move with respect to the knuckle in a second direction corresponding to extension of the prosthetic finger; 
   a second 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 coupled to the knuckle 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 first direction;   a locking mechanism comprising:
 a first component coupled to the first phalange; 
 a second component coupled to the knuckle, the first component configured to prevent the first phalange from moving in the second 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 to allow the first phalange to move in the second 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 second 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 second direction.   
     
     
         3 . The prosthetic finger of  claim 2 , wherein the spring is a torsion spring. 
     
     
         4 . The prosthetic finger of  claim 1 , wherein the link bar extends through the first phalange. 
     
     
         5 . The prosthetic finger of  claim 1 , wherein the knuckle includes an aperture that is used to rotationally couple the first end of the link bar to the knuckle. 
     
     
         6 . The prosthetic finger of  claim 1 , wherein:
 the first component comprises a ratchet; and   the second component comprises one or more teeth.   
     
     
         7 . The prosthetic finger of  claim 6 , 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 first or second directions. 
     
     
         8 . The prosthetic finger of  claim 1 , wherein:
 the first phalange corresponds to a medial phalange of a hand; and   the second phalange corresponds to a distal phalange of the hand.   
     
     
         9 . 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, the first phalange configured to:
 rotate about the knuckle in a first direction corresponding to flexion of the prosthetic finger; and 
 rotate about to the knuckle in a second direction corresponding to extension of the prosthetic finger; 
   a second 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 connected to the knuckle and a second end connected to the second phalange, and configured to couple movement of the first phalange and the second phalange such that when the first phalange rotates about the knuckle the second phalange rotates about second end of the first phalange; and   a locking mechanism coupled to the first phalange and configured to:
 operate in a first state that prevents movement of the first phalange in the second direction; and 
 operate in a second state that allows movement of the first phalange in the second direction. 
   
     
     
         10 . The prosthetic finger of  claim 9 , wherein:
 the locking mechanism is configured to operate in the first state when not being engaged by the user; and   the locking mechanism is configured to operate in the second state when engaged by the user.   
     
     
         11 . The prosthetic finger of  claim 10 , wherein the locking mechanism comprises a button, that when pressed, causes the locking mechanism to transition from the first state to the second state. 
     
     
         12 . The prosthetic finger of  claim 9 , further comprising a torsion spring configured that is configured to move the first phalange in the second direction when the locking mechanism is in the second state. 
     
     
         13 . The prosthetic finger of  claim 9 , 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.   
     
     
         14 . The prosthetic finger of  claim 13 , when the ratchet is connected to the first phalange. 
     
     
         15 . The prosthetic finger of  claim 9 , 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 second phalange.   
     
     
         16 . The prosthetic finger of  claim 15 , wherein:
 the knuckle comprises an aperture; and   the aperture is used to connect the first end of the link bar to the knuckle.   
     
     
         17 . A prosthetic finger comprising:
 a knuckle configured to interface with a prosthetic socket;   a first phalange defining a first end coupled to the knuckle, 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 defining a first end 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 first end of the second phalange to that causes rotation of the second phalange 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.   
     
     
         18 . The prosthetic finger of  claim 17 , 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.   
     
     
         19 . The prosthetic finger of  claim 18 , 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.   
     
     
         20 . The prosthetic finger of  claim 17 , wherein the spring is a torsion spring.