Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Leg – Ankle
Reexamination Certificate
1999-07-14
2001-02-13
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Leg
Ankle
C623S047000
Reexamination Certificate
active
06187052
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to prosthetic devices, and more particularly to articulated prosthetic ankle joints.
2. Description of the Related Art
Currently available prosthetic ankle joints are heavy, bulky, and do not provide a range of motion that imitates a normal foot range of motion during walking. Each foot and ankle during walking travel through stance and swing phases of a gate cycle. In the stance phase, the foot is in contact with the ground and the weight of a person is supported on the foot. In the swing phase, the foot is off the ground as the entire leg and foot move from a posterior position to an anterior position with respect to a center of gravity of the person. The stance phase begins just after completion of the swing phase and commences with a heel strike wherein the foot is lowered to the ground as the body moves forward from a position posterior to the person's center of gravity. Immediately after heel strike, the foot moves from a dorsiflexed position, wherein the toes of the foot are pointed upwards, to a plantarflexed position wherein the bottom of the foot or shoe is flat on the walking surface, which provides greater stability as the entire weight of the person is shifted over the foot in contact with the ground. The swing phase commences just after heel strike of the other foot. During the swing phase, the foot is again in the dorsiflexed position as the foot leaves the walking surface and the foot and leg swing forward in preparation for the stance phase. Dorsiflexion is very important for normal human locomotion, since the toes must be dorsiflexed in order to clear the floor. If the foot were not dorsiflexed during the swing phase, it would most likely catch on the walking surface and cause the person to stumble and fall, leading to potentially serious injury.
With an amputee, it is customary to make the prosthetic limb about ⅜ to ½ inch shorter than the natural limb in order to provide adequate ground clearance for the prosthetic limb during the swing phase. Consequently, the amputee develops an unnatural gate pattern, causing him or her to lean to one side while walking. Over the years, this unnatural gate pattern may cause hip, pelvis, knee and back problems.
In addition, most prosthetic feet and ankle systems are fixed at 90°. During heel strike of the prosthetic foot, the momentum of the person causes the foot to rotate forward to a more stable flat position on the walking surface. However, since there is no flexibility in the ankle, the person is lurched forward. As the person's center of gravity passes over the centerline of the foot, the knee is forced to bend to compensate for the unnatural movement. With above-knee amputees, the prosthetic knee joint may become unstable and cause unwanted or unexpected knee flexure, and may cause the person to fall.
SUMMARY OF THE INVENTION
The present invention overcomes many of the drawbacks of the prior art by the provision of a prosthetic ankle joint that mimics natural ankle motion during walking.
According to the invention, a prosthetic ankle joint is adapted for connection between a pylon (or other interface between the prosthetic ankle joint and the stub of an amputee) and a prosthetic foot for moving the foot between dorsiflexed and plantarflexed positions. The prosthetic ankle joint comprises a base member adapted for connection to the prosthetic foot, a bracket member adapted for connection to the pylon or other interface, and a collapsible and expandable linkage assembly. The linkage assembly includes a first recumbent bar at least operatively associated with the base member, a first upright bar having a lower end pivotally connected to the first recumbent bar at a first pivot joint and an upper end fixedly connected to the bracket member, a second upright bar having a lower end pivotally connected to the first recumbent bar at a second pivot joint, and a second recumbent bar pivotally connected between the first and second upright bars at third and fourth pivot joints, respectively. The first and second upright bars together with the first and second recumbent bars form an interior space. With this arrangement, pivotal movement between the bracket member and the base member between dorsiflexed and plantarflexed positions causes deformation of the interior space.
Preferably, a resilient member, such as a spring, piston, resilient block, or the like, is positioned in the interior space and is deformable upon deformation of the interior space. The resilient member normally biases the base member in the dorsiflexed position and resists rotational movement of the base member from the dorsiflexed position.
Further according to the invention, a prosthetic ankle joint is adapted for connection between a pylon (or other interface) and a prosthetic foot for moving the foot between dorsiflexed and plantarflexed positions. The prosthetic ankle joint comprises a base member adapted for connection to the posthetic foot, a bracket member adapted for connection to the pylon or other interface and pivotally connected to the base member at a first pivot joint, a recumbent bar pivotally connected to the bracket member at a second pivot joint, and an upright bar having a lower end pivotally connected to the base member at a third pivot joint and an upper end pivotally connected to the recumbent bar at a fourth pivot joint. The bracket member together with the base member, the recumbent bar and the upright bar form an interior space. With this arrangement, pivotal movement between the bracket member and the base member between dorsiflexed and plantarflexed positions causes deformation of the interior space.
Preferably, a resilient member is located in, and at least substantially fills the inner space to bias the base member to the plantarflexed position and resist rotational movement of the base member from the plantarflexed position.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.
REFERENCES:
patent: 2208275 (1940-07-01), McCann
patent: 3779654 (1973-12-01), Horne
patent: 3871032 (1975-03-01), Karas
patent: 4446580 (1984-05-01), Furuya et al.
patent: 5030239 (1991-07-01), Copes
patent: 5158570 (1992-10-01), Schey et al.
patent: 5181931 (1993-01-01), Van De Veen
patent: 5405411 (1995-04-01), McCoy
patent: 5425780 (1995-06-01), Flatt et al.
patent: 5443527 (1995-08-01), Wilson
patent: 5545234 (1996-08-01), Collier, Jr.
patent: 5571210 (1996-11-01), Lindh
patent: 5571212 (1996-11-01), Cornelius
patent: 5766264 (1998-06-01), Lundt
patent: 5769896 (1998-06-01), Rosendahl et al.
patent: 5800562 (1998-09-01), Wilkinson
patent: 5800566 (1998-09-01), Gramnas
patent: 5800567 (1998-09-01), Cooper et al.
patent: 5800568 (1998-09-01), Atkinson et al.
patent: 6077301 (2000-06-01), Pusch
Molino Joseph L.
Rebarber Michael
Fridman Lawrence G.
Milano Michael J.
Stewart Alvin
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