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EP-4257092-B1 - LOWER LIMB PROSTHESIS

EP4257092B1EP 4257092 B1EP4257092 B1EP 4257092B1EP-4257092-B1

Inventors

  • BYARS, JONATHAN M.
  • QUINTERO, Hugo
  • CARPENTER, JOHN

Dates

Publication Date
20260506
Application Date
20160304

Claims (11)

  1. A lower limb prosthesis, comprising: a foot member (906, 1308); a main body (902) rotatably coupled to the foot member (906, 1308) at a joint comprising a joint axis (916), wherein the main body (902) comprises a housing, an actuator (918), and a transmission (920), and wherein the actuator (918) is configured to transmit an actuator torque to the transmission (920), and the transmission (920) is configured to transmit a final torque to the foot member (906, 1308); a spring (908, 1306) coupled to the foot member (906, 1308) and the main body (902), wherein the spring (908, 1306) is configured to apply a spring force to the foot member (906, 1308), and wherein the spring force acts in parallel to the final torque; and an engagement mechanism (912) configured to engage and disengage the spring (908, 1306), wherein when the spring (908, 1306) is engaged, the spring (908, 1306) is configured to apply the spring force to the foot member (906, 1308), and when the spring (908, 1306) is disengaged, the spring (908, 1306) is not configured to apply the spring force to the foot member (906, 1308), characterized in that when the spring (908, 1306) is engaged, the spring (908, 1306) engages the main body (902) at an engagement position and that the engagement mechanism (912) is further configured to adjust the engagement position.
  2. The lower limb prosthesis of claim 1, wherein adjusting the engagement position changes a neutral position of the lower limb prosthesis, and wherein the neutral position of the lower limb prosthesis is an angular position of the foot member (906, 1308) relative to the main body (902) at which the engaged spring (908, 1306) is in equilibrium.
  3. The lower limb prosthesis of claim 1, further comprising a controller in electronic communication with the engagement mechanism (912), wherein the engagement mechanism (912) is configured to engage the spring (908, 1306), disengage the spring (908, 1306), and adjust the engagement position in response to a signal from the controller.
  4. The lower limb prosthesis of claim 3, further comprising an engagement position sensor (924) configured to provide an engagement position signal to the controller indicating the engagement position of the spring (908, 1306).
  5. The lower limb prosthesis of claim 3, further comprising a torque sensor configured to provide a torque signal to the controller, wherein the controller is configured to control the engagement mechanism (912) in response to the torque signal.
  6. The lower limb prosthesis of claim 3, further comprising an absolute encoder configured to provide a position signal to the controller indicating the position of the foot member (906, 1308) relative to the main body (902), and wherein the controller is configured to control the engagement mechanism (912) in response to the position signal.
  7. The lower limb prosthesis of claim 1, wherein the engagement mechanism (912) comprises a track, and wherein a portion of the spring (908, 1306) is configured to slide along the track and reversibly lock into an engagement position on the track.
  8. The lower limb prosthesis of claim 1, wherein the engagement mechanism (912) comprises: a chamber (1310) at least partially filled with a hydraulic fluid; a piston (1312) within the chamber (1310), wherein the piston (1312) separates the chamber (1310) into a first side and a second side; a piston rod connecting the piston (1312) to the spring (908, 1306); and a valve (1316) fluidly connected to the first side and the second side, wherein the valve (1316) is configured to be opened to allow hydraulic fluid to move between the first side and the second side and closed to block hydraulic fluid from moving between the first side and the second side, and wherein the piston (1312) is slidable within the chamber (1310) when the valve (1316) is open and fixed relative to the chamber (1310) when the valve (1316) is closed.
  9. The lower limb prosthesis of claim 8, wherein the spring (908, 1306) is in the engaged state when the valve (1316) is closed, and the spring (908, 1306) is in the disengaged state when the valve (1316) is open.
  10. The lower limb prosthesis of claim 9, wherein the valve (1316) is a solenoid valve (1316).
  11. The lower limb prosthesis of claim 10, further comprising a reservoir configured to contain a variable volume of hydraulic fluid in order to compensate for changes in a volume of hydraulic fluid in the chamber (1310).

Description

The embodiments herein relate to lower limb prostheses configured to simulate certain capabilities of an intact human ankle. Until recently, lower limb prostheses were generally passive devices controlled by a user's own motion. Currently, some lower limb prostheses allow for plantar flexion and dorsiflexion movement of a foot member about a joint axis. In addition, microprocessor control (MPC) has been introduced to better mimic the motion of a natural foot and ankle. In MPC prostheses, the microprocessor controls an amount of damping or stiffness in moving a foot member and/or control the lower limb prosthesis to actively propel the user forward while walking. While such lower limb prostheses may provide a more natural motion, design challenges remain. For example, the addition of components that provide new or improved functionality may increase the size, weight, and/or power requirements of the lower limb prostheses. These factors may limit the population, such as pediatric patients, for example, that may benefit from the prostheses because they require a user to exert more energy while walking, and/or decrease the use time between battery charges, which are not suitable for smaller or weaker patients. Thus, a need exists for new lower limb prostheses that offer advantages over standard lower limb devices. US 2012/0330439 A1 relates to a powered knee joint comprising a knee joint and a knee motor unit for delivering power to the knee joint. A powered ankle joint is coupled to the knee joint comprising an ankle joint and an ankle motor unit to deliver power to the ankle joint. A prosthetic foot is coupled to the ankle joint. A plurality of sensors are provided for measuring a real-time input. At least one controller is provided for controlling movement of the prosthesis based on the real-time input, wherein at least one of the knee motor unit or the ankle motor unit comprises at least one drive stage, the at least one drive stage comprising a rotary element for generating torque and at least one looped element affixed around the rotary element and configured for transmitting the torque to another rotary element coupled to a joint to be actuated. US 2004/0064195 A1 relates to a variable impedance prosthesis or orthosis, comprising a proximal end for interfacing to a user, a distal end for interfacing to the environment; a stiffness controller and d. a controllable-spring-rate spring element. US 2011/0257764 A1 relates to a foot and ankle structure coupled for rotation with respect to a shin member at an ankle joint. The foot and ankle structure comprises a controllable actuator with a motor and a series spring connected to impart rotary motion to the foot and ankle structure about the ankle joint. A physical spring is connected in parallel with the actuator that provides an offset stiffness only when the foot and ankle structure is positioned within a predetermined range of angles with respect to the shin member. In one embodiment, not covered by the claimed invention, a lower limb prosthesis is provided, comprising a foot member, and a main body rotatably coupled to the foot member at a joint comprising a joint axis, wherein the main body comprises a housing, an actuator, and a transmission comprising at least one intermediate stage and a final stage, and wherein the actuator is configured to transmit an actuator torque to the transmission, the at least one intermediate stage is configured to transmit an intermediate torque about an intermediate axis, and the final stage is configured to transmit a final torque about the joint axis to the foot member. Themain body may be rotatably coupled to the foot member through a foot coupler, and wherein the final torque may be transmitted to the foot member via the foot coupler. The at least one intermediate stage comprises a first intermediate stage and a second intermediate stage may be engaged with the first intermediate stage, wherein the first intermediate stage may be configured to transmit a first intermediate torque about a first intermediate axis and the second intermediate stage is configured to transmit a second intermediate torque about a second intermediate axis. A direction vector of the first intermediate axis and a direction vector of the second intermediate axis may be parallel or perpendicular to a direction vector of the joint axis. The at least one intermediate stage may comprise a first intermediate stage and a second intermediate stage engaged with the first intermediate stage, wherein the first intermediate stage is configured to transmit a first intermediate torque about the intermediate axis and the second intermediate stage is configured to transmit a second intermediate torque about the same intermediate axis. The first intermediate stage may be an epicyclic stage and the second intermediate stage comprises spur or helical gears, or comprises a belt and a pulley, or a chain and a sprocket, or comprises a second a second epicyclic stage. T