Artificial ankle joint and prosthetic devices formed therewith

• US 6,436,149 B1
• Filed: 08/27/1996
• Issued: 08/20/2002
• Est. Priority Date: 09/30/1994
• Status: Expired due to Fees

• Current Assignee: Richard G. Rincoe
• Original Assignee: Richard G. Rincoe
• Inventors: Rincoe, Richard G.
• Primary Examiner(s): Willse, David H.
• Application Number:
  US08/999,693
• Time in Patent Office: 2,184 Days
• Field of Search: 623/47-52, 623/53, 623/40-42
• US Class Current: 623/47
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/80 Sockets, e.g. of suction type
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30469 using band clamps
• CPC Class Codes: A61F 2002/5007 having elastic means different from springs, e.g. including an elastomeric insert
• CPC Class Codes: A61F 2002/5043 with rotation-limiting stops, e.g. projections or recesses
• CPC Class Codes: A61F 2002/5075 Multiple spring systems including two or more helical springs
• CPC Class Codes: A61F 2002/5098 with rotation-limiting means
• CPC Class Codes: A61F 2002/6614 Feet
• CPC Class Codes: A61F 2002/6657 having a plate-like or strip-like spring element, e.g. an energy-storing cantilever spring keel
• CPC Class Codes: A61F 2002/6854 for locking or unlocking a joint
• CPC Class Codes: A61F 2220/0041 using additional screws, bolts, dowels or rivets, e.g. connecting screws

Abstract

A prosthetic device is provided having a proximal end portion adapted to be secured to an amputee and a distal foot structure. The improvement comprises a pivoting ankle joint disposed between the proximal end portion and the foot structure. This ankle joint includes a matable socket and head assembly interconnecting the proximal end portion and the foot structure for relative movement about a pivot axis between first and second positions. A spring element operates to resiliently bias the socket and head into the first pivot position. A load-sensitive locking mechanism operates, upon the existence of a triggering load which exceeds a predetermined threshold magnitude, to cause the socket and head assembly to lock at a selected locking position, thereby preventing relative pivotal movement. In the absence of the triggering load, relative pivotal movement of the socket and head assembly between the first and second positions is permitted.

Claims

1. In a prosthetic leg device adapted to be worn by a human amputee wherein said leg device has a proximal end portion adapted to be secured to the amputee and a distal foot structure, the improvement comprising a pivoting ankle joint disposed between said proximal end portion and said foot structure, said ankle joint including a matable socket and head assembly that includes a shaft secured to said proximal end portion and extending along a central axis to terminate in said head, said matable socket and head assembly interconnecting said proximal end portion and said foot structure for relative pivotal movement about a pivot axis between a first pivot position wherein said foot structure is oriented at an acute angle with respect to the central axis and a second pivot position wherein said foot structure is oriented at an obtuse angle with respect to the central axis, said socket and head assembly including a socket disposed on one of said proximal end portion and said foot structure and a head sized to be matably received by said socket and disposed on another of said proximal end portion and said foot structure, said pivoting ankle joint further including a load-sensitive locking mechanism associated with said socket and head assembly, said locking mechanism operative in response to a triggering compressive force between said socket and head in excess of a threshold magnitude to cause said socket and head assembly to lock at a selected locking position between the first and second pivot positions corresponding to said foot structure being oriented substantially perpendicular to the central axis, thereby to prevent relative pivotal movement of said socket and head and operative in an absence of a triggering compressive force to permit relative pivotal movement of said socket and head between the first and second positions, and including a spring element associated with said socket and head assembly and operative to resiliently bias said socket and head assembly into the first pivot position.

2. The improvement according to claim 1 including a socket housing disposed on said foot structure, said socket housing being sized and adapted to mount said socket and including a stiff yet resilient first material interposed between said socket and said socket housing.

3. The improvement according to claim 2 wherein said foot structure is constructed of a stiff yet resilient second material.

4. The improvement according to claim 1 wherein said socket is secured to said foot structure.

5. The improvement according to claim 4 wherein said socket has an arcuate sidewall along which an outer peripheral surface of said head pivots, said locking mechanism including a recess formed in said arcuate sidewall and a latch assembly carried by said head, said latch assembly operative in response to the triggering compressive force to engage the recess at the selected locking position.

6. The improvement according to claim 5 wherein said latch assembly includes at least a first rod slidably disposed in a bore formed axially through said shaft and a latch element connected to a first end of said first rod and extending perpendicularly to the central axis, said first rod being resiliently biased to retain said latch element in a retracted state within a channel formed into the outer peripheral surface of said head portion parallel to said pivotal axis so that in the locked position said latch element can move from the retracted state to an extended state thereby to engage said recess.

7. The improvement according to claim 6 wherein said latch assembly includes a second rod slidably disposed within said bore and extending outwardly therefrom opposite said first rod, a first coil spring operative to bias said first rod into the retracted state and a second coil spring operative to resiliently retain said first and second rods in a spaced apart relationship from one another.

8. The improvement according to claim 7 wherein said first coil spring has a first coil spring constant and wherein said second coil spring has a second coil spring constant, said first coil spring constant being equal to or greater than said second coil spring constant.

9. The improvement according to claim 1 including a restraining assembly associated said locking mechanism and operative in a restrained state to disable said locking mechanism so that said head and said socket are permitted to pivot between the first and second pivot positions while by-passing the locking position and in an unrestrained state to enable said locking mechanism.

10. In a prosthetic leg device adapted to be worn by a human amputee wherein said leg device has a proximal end portion adapted to be secured to the amputee and a distal foot structure, the improvement comprising a pivoting ankle joint disposed between said proximal end portion and said foot structure, said ankle joint including a matable socket and head assembly interconnecting said proximal end portion and said foot structure for relative pivotal movement about a pivot axis between first and second pivot positions, said socket and head assembly including a socket disposed on one of said proximal end portion and said foot structure and a head sized to be matably received by said socket and disposed on another of said proximal end portion and said foot structure, said pivoting ankle joint further including a load-sensitive locking mechanism associated with said socket and aid head assembly, said locking mechanism operative in response to a triggering compressive force between said socket and head in excess of a threshold magnitude to cause said socket and head assembly to lock at a selected locking position between the first and second pivot positions thereby to prevent relative pivotal movement of said socket and head and operative in an absence of a triggering compressive force to permit relative pivotal movement of said socket and head between the first and second positions, further including a restraining assembly associated with said locking mechanism and operative in a restrained state to disable said locking mechanism so that said head and said socket are permitted to pivot between the first and second pivot positions while by-passing the locking position and in an unrestrained state to enable said locking mechanism, said restraining assembly including an annular first collar connected to and about said shaft in a stationary condition and an annular second collar connected to said locking mechanism and slideably received by and rotatably mounted onto said shaft, each of said first and second collars having a plurality of alternating longitudinally extending teeth and gaps sized so that when said second collar is rotated into a first angular position to orient said restraining assembly in the restrained state, respective ones of said teeth on each of said first and second collars facially contact each other thereby transferring load forces away from said locking mechanism, and when said second collar is rotated to a second angular position different from said first angular position to orient said restraining assembly in the unrestrained state, respective ones of said teeth on each of said first and second collars slideably move into and out of respective ones of said gaps of said first and second collars thereby enabling said locking mechanism to receive the load.

11. The improvement according to claim 10 wherein said restraining assembly includes a bushing slidably received onto said shaft, a cap slidably received onto said shaft and a retainer ring slidably disposed over said cap and releasably connected to said second collar in a manner so that said retainer ring and said second collar are rotatably connected to said cap and can rotate about said bushing and said shaft.

12. The improvement according to claim 11 wherein said bushing includes a bushing channel formed in an outer peripheral bushing edge thereof and wherein said second collar includes a set screw operably connected to said second collar through an outer peripheral collar edge, said set screw and said bushing channel operative to releasably retain said restraining assembly in one of the restrained state and the unrestrained state.

13. A prosthetic leg device with an artificial ankle joint adapted for use on a human amputee having a residual limb leg portion remaining on an amputated leg of the amputee, comprising:

(a) a prosthetic socket having a socket sized and adapted to releasably receive and retain the remaining residual limb portion of the amputated leg of the amputee;

(b) a shaft extending along a central axis and having a first end portion connected to said prosthetic socket and a head portion disposed opposite of said first end portion;

(c) a foot structure including a socket having an arcuate sidewall, said socket sized and adapted to pivotally receive and retain said head portion of said shaft along an outer peripheral surface of said head portion, whereby said shaft and said socket can pivotally move about a pivotal axis relative to each other between a first pivot position and a second pivot position; and

(d) a load-sensitive locking mechanism associated with said socket and said head portion and operative to prevent relative pivotal movement of said shaft and said socket at a locking position located between the first and second pivot positions when a triggering load exceeding a predetermined threshold load is exerted upon said locking mechanism as said shaft and said socket pivot relative to each other between the first and second pivot positions and to permit relative pivotal movement of said shaft and said socket between the first and second pivotal positions thereby by-passing the locking position when a load is exerted upon said locking mechanism that is less than the triggering load, said locking mechanism including a recess formed in said arcuate sidewall and a latch assembly carried by said head, said latch assembly operative in response to the triggering compressive force to engage the recess at the selected locking position.

14. A prosthetic leg device according to claim 13 including a spring element interconnecting said head portion of said shaft and said socket and operative to resiliently bias said shaft and said socket in the first pivot position.

15. A prosthetic leg device according to claim 13 wherein said foot structure includes a housing sized and adapted to receive said socket and a stiff, yet resilient first material disposed between said socket and said housing and operative to resiliently retain said socket into said housing.

16. A prosthetic leg device according to claim 13 wherein said foot structure includes an artificial foot extending along a longitudinal axis, said artificial foot fabricated from a stiff, yet resilient second material and having a distal toe portion extending longitudinally therefrom and disposed in spaced-relation from said socket.

17. A prosthetic leg device according to claim 16 wherein said artificial foot is disposed at an acute angle relative to said shaft when in the first pivot position to render said toe portion in a toes-up condition, at an obtuse angle relative to said shaft when in the second pivot position to render said toe portion in a toes-down condition and substantially perpendicular to said shaft when in the locked position.

18. A prosthetic leg device according to claim 13 including a restraining assembly associated said locking mechanism and operative in a restrained state to disable said locking mechanism so that said shaft and said socket are permitted to pivot between the first and second pivot positions while by-passing the locking position and in an unrestrained state to enable said locking mechanism.

19. A prosthetic leg device according to claim 13 wherein said prosthetic socket includes a stubshaft interconnecting said socket and said shaft.