Device in a leg prosthesis

• US 20040044417A1
• Filed: 05/13/2003
• Published: 03/04/2004
• Est. Priority Date: 08/25/2000
• Status: Active Grant

• Current Assignee: Gramtec Innovation AB
• Original Assignee: Gramtec Innovation AB
• Inventors: Gramnas, Finn
• Granted Patent: US 6,855,170 B2
• Time in Patent Office: Days
• US Class Current: 623/52
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• CPC Class Codes: A61F 2002/5007 having elastic means different from springs, e.g. including an elastomeric insert elastic coating A61F2002/3007; springs A61F2002/5072; plate-like springs for feet A61F2002/6657
• CPC Class Codes: A61F 2002/5018 for adjusting angular orientation
• CPC Class Codes: A61F 2002/5039 allowing only for single rotation
• CPC Class Codes: A61F 2002/5043 with rotation-limiting stops, e.g. projections or recesses

Abstract

A device in a leg prosthesis which via a pivot axle is connected to the leg prosthesis, wherein first means are arranged to permit a limited rotation of the foot with respect to the leg prosthesis from an initial position, in which the leg prosthesis and the foot have a certain angle with respect to each other and second means are arranged to permit a stepless adjustment of the angle beetween the prosthesis and the foot in the initial position.

Claims

1. A device in a leg prosthesis (2) provided with a foot (3) which via a pivot axle (4) is connected to the leg prosthesis (2), wherein first means (16) are provided to permit a limited rotation of the foot with respect to the leg prosthesis from an initial position, in which the leg prosthesis and the foot has a certain angle relative to each other and second means (17) are arranged to permit a stepless adjustment of the angle between the prosthesis and the foot in the initial position,

characterized in that the device comprises a lever arm (10) which is pivotally supported with respect to said leg prosthesis (2) and said foot (3) and that said lever arm (10) is arranged to cooperate with on one hand said first means (16) at which a limited angular adjustment between the lever arm and the foot is permitted under cooperation with said first means, and on the other hand with said second means (17) at which an angular adjustment between the lever arm and the leg prosthesis is permitted while adjusting said initial position and wherein said second means (17) is arranged to take a first position in which rotation between the lever arm (10) and leg prosthesis (2) is permitted and a second position in which an unrotatable connection between the lever arm and leg prosthesis is provided.

2. A device as claimed in claim 1, characterized in that the second means (17) comprises an element (18) which is displaceable with respect to the leg prosthesis and members for keeping the displaceable element in a desired displacement position.

3. A device as claimed in claim 2, characterized in that the displaceable member comprises a piston (18) with outwards directed ring flanges (22, 23), which is displaceable in a cylinder (24) attached to the leg prosthesis, and that the members for keeping the piston in a desired displacement position with respect to the cylinder comprise as ring wall (25) in the cylinder dividing the space between the ring flanges of the piston into two chambers (20, 21) and a two-way valve (19) which in open position permits flow of medium present in the chambers (20, 21) therebetween and in closed position prevents such flow.

4. A device according to claim 3, characterized in that said cylinder has a symmetry axis (27) making an angle with a longitudinal axis (28) of the leg prosthesis.

5. A device according to claim 4, characterized in that said second means (17) permits an adjustment of said initial position between a first angular position in which the leg prosthesis is rotated maximally forwards towards a toe portion of said foot and a second angular position in which the leg prosthesis is rotated maximally backwards towards a heel portion of said foot.

6. A device according to claim 5, characterized in that said symmetry axis (27) is arranged substantially in parallel with said lever arm (10) when the leg prosthesis has taken its second angular position.

7. A device according to any of the preceding claims, characterized in that said lever arm (10) is supported in an axle which is common with said pivot axle (4) connecting the foot (3) to the leg prosthesis (2).

8. A device according to any of the preceding claims, characterized in that said lever arm has a first end (13) extending from said pivot axle (4) backwards towards a heel area (14) of the foot and a second end (15) extending from said pivot axle forwards towards the frondtarea of the foot, that said first end is arranged to cooperate with said first means (16) and that said second end is arranged to cooperated with said second means (17).

9. A device according to claim 8, characterized in that said second end (15) is coupled to said second means through a link (26) which is pivotally supported at both of its ends.

10. A device according to claim 8 or 9, characterized in that said first means (16) comprises a flexible body arranged between the foot and the first end (13) of the lever arm at which the flexible body is adapted to be compressed upon rotation of the lever arm towards the foot at the first end of the lever arm.