ANKLE FOOT ORTHOSIS

Abstract

An ankle foot orthosis having a lower leg element, a foot element, and a first energy storing unit being adapted such that moving the foot element relative to the lower leg element in dorsiflexion direction from a position in which the amount of energy stored in the first energy storing unit is minimal loads the first energy storing unit with energy. The first energy storing unit is adapted such that the amount of energy stored in the first energy storing unit is increased by moving the foot element relative to the lower leg element in a plantar flexion direction from a first position in which the amount of energy stored in the first energy storing unit is minimal into a second position and moving the foot element relative to the lower leg element in dorsiflexion direction from the second position back into the first position.

Claims

1-19. (canceled)

20. An ankle foot orthosis comprising: a lower leg element; a foot element pivotably coupled to the lower leg element; a first energy storing unit comprising a pressure chamber, the first energy storing unit configured to store additional energy in the form of an increased pressure in the pressure chamber in response to: moving the foot element relative to the lower leg element in a plantar flexion direction from a first position in which an amount of energy already stored in the first energy storing unit is at a minimum amount into a second position to increase the amount of energy stored in the first energy storing unit; and moving the foot element relative to the lower leg element in a dorsiflexion direction from the second position back into the first position to increase the amount of energy stored in the first energy storing unit.

21. The ankle foot orthosis according to claim 20, further comprising a heel cylinder and a heel cylinder piston, the heel cylinder in fluid communication with the pressure chamber.

22. The ankle foot orthosis according to claim 21, further comprising a rod attached to a heel part of the foot element and to the heel cylinder piston.

23. The ankle foot orthosis according to claim 22, wherein the heel cylinder comprises two first valves configured to control a flow of air between the heel cylinder and the pressure chamber.

24. The ankle foot orthosis according to claim 23, wherein the two first valves are configured to open under pressure.

25. The ankle foot orthosis according to claim 24, wherein the heel cylinder comprises two second valves configured to open due to suction.

26. The ankle foot orthosis according to claim 25, further comprising a pressure sensor attached to the heel part of the foot element.

27. The ankle foot orthosis according to claim 26, further comprising a forefoot cylinder, a tube, and a forefoot cylinder piston within the forefoot cylinder and attached to the foot element, wherein the tube connects the forefoot cylinder and the pressure chamber in fluid communication.

28. The ankle foot orthosis according to claim 27, further comprising an electric valve positioned within the tube and configured to control a flow of air within the tube.

29. The ankle foot orthosis according to claim 28, wherein the electric valve is configured to open when the pressure sensor does not detect any pressure and close when the pressure sensor detects pressure.

30. The ankle foot orthosis according to claim 29, wherein, during a heel strike, the pressure sensor detects pressure, the electric valve is closed, the rod moves the piston upward to increase a pressure in the heel cylinder, and the two first valves channel a flow of air into the pressure chamber increasing a pressure within the pressure chamber.

31. The ankle foot orthosis according to claim 30, wherein, when the heel part leaves the ground, the pressure sensor no longer detects pressure, the electric valve is opened, the tube channels a flow of air from the pressure chamber to the forefoot cylinder, and the flow of air pushes the forefoot cylinder piston downward to cause a powered plantarflexion.

32. The ankle foot orthosis according to claim 31, wherein the powered plantarflexion causes the rod to push the heel cylinder piston upward to increase a pressure within the heel cylinder.

33. The ankle foot orthosis according to claim 32, wherein the powered plantarflexion causes the rod to pull the heel cylinder piston downward to decrease a pressure within the heel cylinder.

34. The ankle foot orthosis according to claim 20, wherein the pressure chamber further comprises a first pressure chamber, wherein the ankle foot orthosis further comprises a second energy storing unit comprising a second pressure chamber, and wherein moving the foot element relative to the lower leg element in a plantar flexion direction increases the amount of energy stored in the first pressure chamber and moving the foot element relative to the lower leg element in a dorsiflexion direction increases the amount of energy stored in the second pressure chamber.

35. An ankle foot orthosis comprising: a lower leg element; a foot element pivotably coupled to the lower leg element; a first energy storing unit comprising a pressure chamber, wherein the first energy storing unit is adapted such that moving the foot element relative to the lower leg element in a plantar flexion direction from a first position to a second position increases an amount of energy stored in the pressure chamber in the form of a pressure increase.

36. The ankle foot orthosis according to claim 35, wherein a pressure inside the pressure chamber is increased when the foot element is moved relative to the lower leg element in the plantar flexion direction from the first position to the second position.

37. The ankle foot orthosis according to claim 36, wherein the pressure inside the pressure chamber is increased when the foot element is moved relative to the lower leg element in a dorsiflexion direction from the second position to the first position.

38. A method for controlling an ankle foot orthosis comprising: providing the ankle foot orthosis with a lower leg element, a foot element pivotably coupled to the lower leg element, and a first energy storing unit comprising a pressure chamber; moving the foot element relative to the lower leg element in a plantar flexion direction from a first position to a second position, wherein a pressure inside the pressure chamber is increased when the foot element is moved relative to the lower leg element in the plantar flexion direction from the first position to the second position; and moving the foot element relative to the lower leg element in a dorsiflexion direction from the second position to the first position, wherein the pressure inside the pressure chamber is increased when the foot element is moved relative to the lower leg element in a dorsiflexion direction from the second position to the first position, wherein the pressure increase in the pressure chamber comprises additional energy for the ankle orthosis that is stored in the pressure chamber in the form of a pressure increase.

39. The method of claim 38, further comprising initiating a powered plantarflexion.

Description

[0055] FIG. 1 shows a schematic view of an ankle foot orthosis according to one embodiment of the present invention,

[0056] FIG. 2 shows the schematic view of a joint comprising an energy storing unit,

[0057] FIG. 3 schematically shows how an ankle foot orthosis according the present invention works,

[0058] FIG. 4 shows a schematic view of an ankle foot orthosis according to another embodiment of the present invention and

[0059] FIG. 5 shows an schematic view of a different embodiment of the present invention.

[0060] FIG. 1 shows an ankle foot orthosis 1 according to a first embodiment of the present invention. It comprises a foot element 2 and a lower leg element 4. Between the foot element 2 and the lower leg element 4 there is a first joint 6 and a second joint 8.

[0061] Underneath the foot element 2 there are two pressure sensors 10 that are connected via cables 12 with an electronic control unit 14. The electronic control unit 14 is connected to a battery 16 and is adapted to send control signals to two solenoids 18. Once one of these solenoids is activated it decouples the corresponding energy storing unit, which are not shown in FIG. 1, from the corresponding joint.

[0062] FIG. 2 shows a schematic detailed view of a joint. It is connected to the foot element 2 and the lower leg element 4 and comprises a spring element 20 which acts as the corresponding energy storing unit. The spring element 20 is connected with its first end 22 to the foot element 2 and with its second end 24 to a ratchet 26.

[0063] The foot element 2 and the lower leg element 4 are connected by the joint and can be pivoted relative to each other around a rotation axis 28.

[0064] The solenoid 18 is connected via a rod 30 to a pawl 32 which is connected pivotable around a pivot axis 34. The solenoid is connected to the lower leg element 4.

[0065] In the situation shown in FIG. 2 teeth 36 of the pawl engage the teeth 38 of the ratchet 26. FIG. 2 shows a first joint 6. In the situation shown in FIG. 2 a movement of the foot element 2 relative to the lower leg element in plantar flexion direction denoted by arrow 40 is allowed by a combination of ratchet 26 and pawl 32. Due to the special shape of the corresponding teeth this movement is allowed. In contrast, moving the foot element 2 relative to the lower leg element 4 in dorsiflexion direction which is denoted by arrow 42 is prohibited by the corresponding teeth of the ratchet 26 and the pawl 32. Moving the foot element 2 relative to the lower leg element in the direction of arrow 42 leads to a tensioning of the spring element 20 and thus to a loading of the corresponding energy storing unit.

[0066] FIG. 3 schematically shows a gait cycle. The full line shows a typical gait cycle of a healthy person. With the dashed line the movement of the ankle foot orthosis according to an embodiment of the present application is shown. First at the beginning of the controlled plantar flexion phase the heel is set onto the floor. Afterwards the controlled plantar flexion phase starts. Here the foot element 2 is moved relative to the lower leg element in plantar flexion direction. This means that the first neutral setting of the first joint gets shifted towards plantar flexion direction to the point indicated with reference 44. At the same time the second energy storing unit stores energy.

[0067] Afterwards the controlled dorsiflexion phase begins until the maximum dorsiflexion point denoted with reference number 46. This point indicates the end of the controlled dorsiflexion phase. At the beginning of this phase the energy stored in the second energy storing unit is released while the first energy storing unit gets loaded with energy. Afterwards in the powered plantar flexion phase the energy stored in the first energy storing unit is released again until the swing phase starts. In the swing phase advantageously the first energy storing unit is uncoupled from the first joint so that the energy stored in the second energy storing unit can be released leading to a lifting of the toe.

[0068] The dotted line denotes the movement of an orthosis according to the prior art. In the lower parts of FIG. 3 it is shown how the first joint 6 and the second joint 8 act in the different phases of the gait. When then pawl 32 engages the teeth 38 of the ratchet 26 energy can be stored in or released from the energy storing unit.

[0069] FIG. 4 shows another embodiment of the present application. The ankle foot orthosis 1 comprises a foot element 2 and a lower leg element 4. There is a first joint 6 and a second joint 8. In contrast to the embodiment shown in FIGS. 1 and 2 there are no spring elements acting as energy storing units. In contrast there is a high drawl existent comprising tubes 48 and two pressure reservoirs 50 that act as energy storing units.

[0070] FIG. 5 shows a different embodiment of the present invention. It comprises a pressure chamber 52 which is on its left side connected to a heel cylinder 54 which is shown in an enlarged view in the top part of FIG. 5. On the right side of the heel cylinder there are two valves 56 which open under pressure while on the left side of the heel cylinder 54 there are two valves 58 opening due to suction. Inside the heel cylinder 54 there is a piston 60 which is coupled by a rod 62 to the heel part 64 of the foot element 2.

[0071] At the heel part 64 of foot element 2 there is a pressure sensor 10. The pressure chamber 52 is coupled to a forefoot cylinder 66 via a tube 68. At the connection between the tube 68 and the pressure chamber 52 there is an electric valve 70. The electric valve 70 is opened when there is no pressure measured by the pressure sensor 10. The electric valve 70 is closed when the pressure sensor 10 detects a pressure.

[0072] A piston 60 inside the forefoot cylinder 66 is biased by a spring 72. On top of the pressure chamber 52 there is a cover 74 carrying a battery 76 and a micro controller 78.

[0073] During heel strike the pressure sensor 10 detects a pressure so that the electric valve 70 is closed. The valve stays closed as long as the heel part 64 of the foot element 2 is in contact with the ground. During controlled plantarflexion phase and controlled dorsiflexion phase the piston 60 is moved up and down inside the heel cylinder 54 thereby increasing the pressure inside the pressure chamber 52. In the plantarflexion phase the spring 72 is compressed. It relaxes in the first part of the controlled dorsiflexion phase and gets elongated until the maximum dorsiflexion angle at the end of the controlled dorsiflexion phase is reached.

[0074] When the heel leaves the ground the pressure sensor 10 does not detect any pressure anymore so that the electric valve 70 opens. Inside the pressure chamber 52 there is a high pressure which is now released through the tube 68 into the forefoot cylinder 66 thereby pushing the piston 60 inside the forefoot cylinder 66 downwards. This leads to a powered plantarflexion phase and to a compression of the spring 72. Once the pressure inside the pneumatic system and in particular inside the pressure chamber 52 is released and the toe leaves the ground the spring 72 relaxes and lifts the toe area of the foot element 2 in the swing phase.

REFERENCE LIST

[0075] 1 ankle foot orthosis [0076] 2 foot element [0077] 4 lower leg element [0078] 6 first joint [0079] 8 second joint [0080] 10 pressure sensor [0081] 12 cable [0082] 14 electronic control unit [0083] 16 battery [0084] 18 solenoid [0085] 20 spring element [0086] 22 first end [0087] 24 second end [0088] 26 ratchet [0089] 28 rotation axis [0090] 30 rod [0091] 32 pawl [0092] 34 pivot axis [0093] 36 teeth [0094] 38 teeth [0095] 40 arrow [0096] 42 arrow [0097] 44 maximum plantar flexion angle at the end of controlled plantarflexion phase [0098] 46 maximum dorsiflexion angle at the end of controlled dorsiflexion phase [0099] 48 tube [0100] 50 pressure reservoir [0101] 52 pressure chamber [0102] 54 heel cylinder [0103] 56 valve opening under pressure [0104] 58 valve opening due to suction [0105] 60 piston [0106] 62 rod [0107] 64 heel part [0108] 66 forefoot cylinder [0109] 68 tube [0110] 70 electric valve [0111] 72 spring [0112] 74 cover [0113] 76 battery [0114] 78 micro controller