Artificial leg with hydraulic knee flexion resistance
First Claim
1. An artificial leg comprising:
- an upper leg component,a lower leg component,knee pivoting means pivotally coupling the lower leg component to the upper leg component to permit knee flexion and extension movements,an hydraulic piston and cylinder assembly coupled between said upper and lower leg components to resist at least said flexion movement during the stance phase, andautomatic control means for altering the degree to which the piston and cylinder assembly resists the flexion movement,wherein one of said leg components includes at least two portions, one of which is coupled to the other of said leg components by said knee pivoting means and is movable relative to the other of said two portions in response to the application of an axial load to said one leg component, andwherein the control means are responsive to said relative movement of said leg component portions to increase the resistance of said piston and cylinder assembly to said flexion movement when the knee flexion angle is within a first knee flexion angle range, but are comparatively unresponsive when the knee flexion angle is within a second knee flexion angle range which is above said first angle range.
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Accused Products
Abstract
An artificial leg includes a knee mechanism having means for restricting knee flexing movement during the stance phase of the walking cycle. The restricting means includes a piston and cylinder assembly so coupled in the mechanism that the piston is movable in the cylinder with knee flexion and extension. The knee mechanism includes two chassis parts arranged to move relatively to each other when an axial load is applied to the limb. One end of the piston and cylinder assembly is connected to one of the chassis parts while the other chassis part engages a control member coupled to a valve inside the piston and cylinder assembly so that the valve is operated in response to relative load-dependent movements of the chassis parts in order to restrict the flow of fluid and thereby create resistance to knee flexion during the stance phase. The chassis parts are connected together by an anterior pivot joint and are resiliently moveable relative to each other according to applied load. The piston and cylinder assembly is also operable to resist movement during the swing phase of the walking cycle, and the interaction of the knee chassis parts with the control member is arranged so that movement of the member is reduced or does not occur at all for flexion angles greater than a predetermined value between 30° and 40°.
82 Citations
22 Claims
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1. An artificial leg comprising:
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an upper leg component, a lower leg component, knee pivoting means pivotally coupling the lower leg component to the upper leg component to permit knee flexion and extension movements, an hydraulic piston and cylinder assembly coupled between said upper and lower leg components to resist at least said flexion movement during the stance phase, and automatic control means for altering the degree to which the piston and cylinder assembly resists the flexion movement, wherein one of said leg components includes at least two portions, one of which is coupled to the other of said leg components by said knee pivoting means and is movable relative to the other of said two portions in response to the application of an axial load to said one leg component, and wherein the control means are responsive to said relative movement of said leg component portions to increase the resistance of said piston and cylinder assembly to said flexion movement when the knee flexion angle is within a first knee flexion angle range, but are comparatively unresponsive when the knee flexion angle is within a second knee flexion angle range which is above said first angle range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A knee mechanism for rotatably connecting a shin component of an artificial leg to a thigh component of the leg, wherein the mechanism comprises:
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a first part for connection to one of said components, a second part movable relative to said first part in response to the application of a load to said one component, the load being directed axially of the component, knee pivoting means for pivotally coupling the second part to the other of said components, an hydraulic piston and cylinder assembly coupled to one of the said parts and arranged to be coupled to said other component for resisting flexion movement of said one component relative to said other component during the stance phase, and automatic control means for altering the degree to which the piston and cylinder assembly resists the flexion movement, wherein the control means are responsive to said relative movement of said first and second parts of the mechanism to increase the resistance of said piston and cylinder assembly to said flexion movement when the knee flexion angle of said one component with respect to said other component is within a first knee flexion angle range, but are comparatively unresponsive when said knee flexion angle is with a second knee flexion angle range which is above the first angle range.
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17. An artificial leg comprising:
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an upper leg component; a lower leg component; knee pivoting means pivotally coupling the lower leg component to the upper leg component to permit knee flexion and extension movements, an hydraulic piston and cylinder assembly coupled between said upper and lower leg components to resist at least said flexion movement during the stance phase, and automatic control means for altering the degree to which the piston and cylinder assembly resists the flexion movement, wherein one of said leg components includes at least two portions, one of which is coupled to the other of said leg components by said knee pivoting means and is configured to move generally in the direction of a longitudinal axis of said one leg component relative to the other of said two portions in response to the application of an axial load to said one leg component in the direction of said longitudinal axis, wherein the piston and cylinder assembly has two ends each pivotally connected to a respective one of the leg components, and wherein that end of said assembly which is connected to said one leg component is pivotally connected to said one leg component portion; and wherein the control means are responsive to said load-responsive relative movement of the two leg component portions to increase the resistance of said piston and cylinder assembly to said flexion movement. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification