DE102020134226A1 - knee brace - Google Patents

Abstract

The invention relates to an artificial knee joint 2, dasa. at least one joint upper part 4, b. at least one joint lower part 6, which is arranged pivotable about at least one pivot axis 14 on one another, andc. has at least one force transmission element 16 for applying a torque to at least one upper joint part 4 and/or at least one lower joint part 6, which is arranged with its one end 18 on the upper joint part 4 and with the opposite end 20 on the lower joint part 6, with the knee joint 2 being at least has a stop 12 against which the force transmission element 16 abuts from a predetermined pivoting angle between the upper joint part 4 and the lower joint part 6 .

Description

The invention relates to an artificial knee joint which has at least one upper joint part, at least one lower joint part, which are arranged on one another such that they can be pivoted about at least one pivot axis, and at least one force transmission element which is arranged at one end on the upper joint part and at the opposite end on the lower joint part .

Artificial knee joints have been known from the prior art for a long time and are used, for example, in orthopedic devices, in particular knee orthoses, knee prostheses or exoskeletons, in order to support and protect knees, for example after an operation, or, for example, to limit a range of motion at least for a period of time or to compensate for the lack thereof . In order to achieve a gait pattern that is as true to nature as possible and, for example, to reduce the risk of stumbling, it is known from the prior art to use a so-called extension. This can be designed, for example, in the form of the force transmission element. It is used to apply a force from one joint part, for example the lower joint part, to the other joint part, for example the upper joint part. This creates a torque that acts in the direction of extension of the joint. The energy required for this is provided, for example, by an elastic energy store. This energy storage is tense, i.e. charged with potential energy, when the knee is bent. As a result, the advancer creates a force that assists in extending the knee. In this way, for example, in a swing phase of a gait cycle in which the respective leg is not in contact with the ground, the knee is stretched and the foot is brought forward. Hence the term "presenter".

In such prior art extenders, the force is applied whenever the knee is bent. While this is beneficial during swing phases, it is undesirable on other occasions. If, for example, the wearer of a knee orthosis sits with bent legs and thus also with bent knees, an advancer from the prior art always exerts a force through which a stretching moment is exerted on the knee. As a result, the wearer either involuntarily stretches the leg, which is neither desirable nor sensible, particularly when sitting, or he must permanently exert a corresponding counterforce in order to prevent the leg from stretching.

The invention is therefore based on the object of improving an artificial knee joint in such a way that these disadvantages are eliminated or at least mitigated.

The invention solves the problem set by an artificial knee joint according to the preamble of claim 1, which is characterized in that the knee joint has at least one stop against which the force transmission element rests from a predetermined pivot angle between the upper joint part and the lower joint part. In a preferred embodiment, this stop is arranged near the pivot axis, particularly preferably on the pivot axis. In a particularly preferred embodiment, the elastic energy store runs through the pivot axis when it is in contact with the stop. In this situation, the pivot axis and the course of the elastic energy store consequently intersect.

Neither the at least one upper joint part nor the at least one lower joint part necessarily has to consist of a single component. In most cases, different components are connected to form the lower joint part or the upper joint part. This is the case, for example, with orthosis shells. It is irrelevant for the function of the present invention on which of these optionally many components that form the joint upper part or the joint lower part one of the ends of the force transmission element is arranged. It is only important that a torque is generated by a force transmitted by means of the force transmission element, at least as long as the force transmission element is not in contact with the stop. The at least one force transmission element is preferably set up to transmit a tensile force. It is preferably designed as a band, cable, chain, flexible rod and/or in the form of several rods or rods connected to one another via joints.

The at least one upper joint part and the at least one lower joint part are pivotable about at least one pivot axis. This can be a simple pivot axis of a pivot joint, for example a hinge joint. However, the upper joint part and the lower joint part can also be connected to one another by multiple links or multiple joints, which have multiple pivot axes and/or at least one movable pivot axis. It is important that the upper joint part and the lower joint part can at least also perform a pivoting movement relative to one another. This can, but does not have to, be overlaid by a linear movement and/or contain a movement of the pivot axis.

If the knee on which the knee joint is arranged, for example as part of an orthopedic device, is bent, the upper joint part and the lower joint part are pivoted relative to one another. The force transmission element preferably extends in a straight line between the two ends at least in sections, but preferably along its entire extent. The connecting line between the two fastening points, with which one end is fastened to one of the joint parts, shifts when the upper joint part is pivoted relative to the lower joint part, ie when bending or straightening the knee. In the fully extended state of the knee, the connecting line between the two ends of the force transmission element preferably runs in front of the pivot axis, ie anterior to it. The force applied therefore generates a torque, the magnitude of which depends not only on the size of the force applied but also on the distance between the connecting line and the pivot axis. If the knee is now bent, the lower joint part is pivoted relative to the upper joint part and the connecting line between the two ends of the force transmission element is pushed posteriorly, ie backwards. The line and thus also the power transmission element sweeps over the pivot axis at a certain angle. If the knee is bent more than this specific angle, the line and thus the force transmission element runs behind, ie posteriorly, the pivot axis.

As long as the force transmission element is in front of the pivot axis, the applied force leads to an extension moment, ie a torque that supports the extension of the knee. However, if the connecting line between the two ends of the force transmission element is behind the pivot axis, the sign of the torque generated by the force changes, which is then a bending moment. This is not suitable for presenters.

According to the invention, the knee joint therefore has at least one stop against which the force transmission element rests as soon as the upper joint part is pivoted relative to the lower joint part by more than the predetermined pivot angle. Different effects can be produced by skilfully selecting the position of the at least one stop.

If the at least one stop is positioned on the knee joint in such a way that the force transmission element runs in front of the pivot axis when it rests against the stop, the force transmission element prevents a bending moment from being able to be applied. The torque generated by the power transmission element will consequently always be an extension torque and will support the extension of the knee. The magnitude of the torque that is generated by the force applied by the force transmission element in this state depends on how far the stop is from the pivot axis. This distance defines the lever and thus the moment arm. The larger the lever, the greater the torque generated.

By skilfully selecting the position of the at least one stop, the torque that is generated by the at least one force transmission element when it is in contact with the stop can consequently be influenced. The stop is therefore preferably positioned close to the pivot axis. In this case, the torque generated by the power transmission element is small when the predetermined pivot angle is exceeded. The pivot axis preferably runs so close to the stop that the force transmission element runs through the pivot axis when it is in contact with the stop. In this case, although a tensile force is transmitted by the force-transmitting element, this is directed directly in the direction of the pivot axis, ie radially, and therefore does not lead to a torque. If the force transmission element is a band, for example made of rubber, with a circular cross section, the distance between the stop and the pivot axis preferably corresponds to the radius of the cross section of the force transmission element.

The stop is preferably arranged in such a way that the torque applied by the force transmission element is reduced when the predetermined swivel angle is exceeded.

In a preferred embodiment, the knee joint has at least one energy store that generates a force that is transmitted by the at least one force transmission element. The energy store is preferably an elastic energy store or has one. In principle, any type of energy store that is known from the prior art and is set up to provide the required power can be used as the energy store. This can be done mechanically, hydraulically, pneumatically, magnetically and/or electrically. The energy store is preferably designed to be elastic, for example in the form of a spring element and/or in the form of a rubber-elastic element. This configuration is structurally particularly simple and low-maintenance, since it manages at least with almost no moving parts. In addition, no energy source is required, since such an energy store receives the required energy from the movement of the joint and the wearer of an orthopedic device.

When the upper joint part is pivoted relative to the lower joint part, the distance between the two ends of the force transmission element with which it is arranged on the upper joint part or on the lower joint part increases. The energy store is consequently charged and tensioned with potential energy. As a result, it exerts a force on both the upper joint part and the lower joint part, which acts in the direction of the energy store.

In a particularly preferred embodiment, the at least one energy store contains or forms the at least one force transmission element. In particular, if the at least one energy store is designed as an elastic element, it can be used as a force transmission element. One end of an elastic element is then connected, for example, to the upper joint part and the other end to the lower joint part. Of course, the energy store and the force transmission element can also be designed as separate elements if the energy store is designed as an elastic element.

If the energy store and the force transmission element are designed as separate components, it is possible to place the energy store at a suitable location without having to be physically close to the pivot axis or to the attachment points at which the force transmission element is arranged on the respective joint parts.

The force transmission element is preferably arranged detachably on the upper joint part and/or on the lower joint part. This is particularly advantageous when the power transmission element is part of the energy store or is formed by it. In this way, it is then particularly easy to replace the elastic energy store with another energy store, for example a spring element with a different spring constant. For this purpose, the energy store to be exchanged only has to be removed from the upper joint part and/or the lower joint part and replaced by another one.

In a preferred embodiment, the force transmission element can be fastened at several points on the joint upper part and/or on the joint lower part. The prestressing of the elastic energy store is particularly preferably adjustable. The different locations can be located at different distances from the pivot axis. In this case, the distance between the fastening points on the joint upper part and the fastening points on the joint lower part differs depending on the selected point. This means that the preload of the elastic energy store varies. On the other hand, the different points can also be arranged in different positions along the circumference around the pivot axis. In this way, the predetermined swivel angle from which the force transmission element rests against the stop can be adjusted. Of course, combinations of the various distinctions are also possible. In a particularly preferred embodiment, a positive-locking element, for example a Velcro fastener, is arranged on at least one end, but preferably on both ends, of the force transmission element, which can interact positively with a correspondingly designed counter-element in order to fasten the respective end. The counter-element is preferably located on the upper joint part and/or on the lower joint part. Particularly preferably, the form-fitting element and the corresponding counter-element allow a stepless change in the fastening point of the force-transmitting element.

At least one of the ends of the force transmission element is preferably arranged on the respective joint part by means of a displaceable carriage. As a result, a preload and/or the predetermined swivel angle can be changed without detaching the force transmission element from the respective joint part.

The elastic energy store preferably has at least one rubber-elastic element, for example a helical spring.

In a preferred embodiment of the knee joint, the predetermined pivoting angle from which the force-transmitting element bears against the stop can be adjusted. This can be achieved in a particularly simple manner by adjusting the position of the stop and/or the position of one or both ends of the force transmission element. The knee joint preferably has at least one motor which is set up to adjust the position of the stop and/or the position of one or both ends of the force transmission element.

Advantageously, the force transmission element applies a torque in a first and a third angular range between the lower joint part and the upper joint part and does not apply a torque in a second angular range lying between the two angular ranges. This is advantageous, for example, so that no torque is applied in a predetermined second angular range, which is preferably arranged around an angle of 90°. This angle range corresponds to the knee angle when sitting. Will the knee bent further, for example when kneeling, the second angular range is exceeded and the third angular range is reached, in which support is desired and therefore a torque is applied.

A preferred orthopedic device, in particular a knee orthosis, has at least two knee joints of the type described here, which each have an upper joint part, a lower joint part arranged pivotably thereon, a force transmission element and a stop and function in the manner described here. The at least two knee joints preferably have different, predetermined pivoting angles and/or different force transmission elements and/or different energy stores. In particular, the elastic energy stores can be designed identically or differently, so that an individual adjustment is possible. The two knee joints preferably have different, predetermined pivoting angles, from which the respective energy store rests against the respective stop. It is thus possible that at a certain pivoting angle in one of the knee joints used the energy storage device is already in contact with the stop, while in the other knee joint the energy storage device is not yet in contact with the respective stop. The course of the torque, which can be represented as a combination of the two torques generated, can be adjusted in many different ways.

• 1 bis 7 - schematische Darstellungen eines Kniegelenkes für eine Knieorthese gemäß einem ersten Ausführungsbeispiel der vorliegenden Erfindung,
• 8 bis 24b- schematische Darstellungen von Kniegelenken gemäß weiterer Ausführungsformen der vorliegenden Erfindung teilweise in unterschiedlichen Schwenkzuständen.

An exemplary embodiment of the present invention is explained in more detail below with the aid of the accompanying drawings. Show it:

• 1 until 7 - Schematic representations of a knee joint for a knee orthosis according to a first embodiment of the present invention,
• 8th until 24b - Schematic representations of knee joints according to further embodiments of the present invention, some in different pivot states.

the 1 until 7 each show a knee joint 2 which has an upper joint part 4 and a lower joint part 6 . Both the upper joint part 4 and the lower joint part 6 have a fastening block 8 , which is not shown as a separate component, arranged via which one end of an elastic energy accumulator 10 is arranged on the upper joint part 4 or the lower joint part 6 . In the exemplary embodiment shown, the elastic energy store 10 forms the force transmission element. The knee joint 2 also has a stop 12.

1 shows a knee joint 2 in the nearly stretched state. The energy store 10 extends between the two mounting blocks 8 and runs frontally, ie in front of the stop 12. Depending on the energy store used, a tensile force is produced between the two mounting blocks 8. This forms an extending moment, i.e. a moment that supports the extension of the joint.

2 shows the joint in the further reflected state. A swivel angle of about 30° is shown. The distance between the two attachment points at which the ends of the energy storage device 10 are arranged on the attachment blocks in FIG. 8 has increased, so that the energy storage device 10 has been energetically charged and is now one compared to the 1 exerts greater force. The location of the energy store 10 has compared to 1 shifted posteriorly. An extending moment is still applied.

3 shows the joint at a pivoting angle of about 70°, which is the predetermined pivoting angle in the exemplary embodiment shown. It can be seen that the energy store 10 is in contact with the stop 12 . As a result, the energy store 10 is divided into two sections. The first section extends from the upper fastening block 8, which is arranged on the upper joint part 4, to the stop 12. It exerts a force on the upper fastening block 8 and thus on the upper joint part 8, which force is directed radially precisely onto the pivot axis. A torque is not generated as a result. A further pivoting of the knee joint 2 does not change anything, as in 4 shown. Here the swivel angle is 90° and the contact point with which the energy store 10 bears against the stop 12 has not changed. The energy store 10 is still divided into two sections. The first section still extends from the upper mounting block 8 to the stop 12. While it has been enlarged so that more pulling force is exerted, it is still directed directly at the pivot axis so no torque is generated.

The same applies to the second section, which extends from the stop to the lower fastening block 8. It also exerts a tensile force on the respective fastening block 8, which is directed axially towards the pivot axis and therefore does not generate any torque.

In the 5 until 7 a knee joint 2 is shown, in which the energy store 10 is arranged at a different point on the two fastening blocks 8 . During the energy storage 10 in the 1 until 4 on the left of the mounting block 8 is arranged, which is indicated by the line shown parallel to the force transmission element 10, these fastening points are in 5 and 6 located further to the right. 5 shows the knee joint 2 with a small pivoting angle between the upper joint part 4 and the lower joint part 6. It corresponds to that in 1 shown swivel angle. The energy store 10 applies an extending moment that is smaller than that in an identical energy store 10 1 generated moment. This is because the energy store 10 in the embodiment in 5 runs closer to the pivot axis and therefore generates a smaller torque.

6 shows the knee joint 2 5 with a swivel angle of 30°. It can be seen that by changing the fastening position at which the energy store is arranged on the fastening blocks 8, the energy store 10 is already in contact with the stop 12 at this relatively small pivoting angle and therefore no more torque is generated. 7 shows the joint 2 in the further flexed state, in which the force-transmitting element is still in contact with the stop 12.

In the 8th until 16 a knee joint 2 is shown schematically in each case, which has an upper joint part 4 and a lower joint part 6 which are arranged on one another such that they can be pivoted about a pivot axis 14 . Each of the knee joints 2 shown also has the stop 12 against which a force transmission element or the energy store 10, if this forms the force transmission element, rests when a predetermined pivoting angle is reached. These components are identical for all the joints shown, so that a more detailed description of the individual figures can be dispensed with.

This in 8th Knee joint 2 shown has an energy store 10, which can be designed, for example, as a spring element or rubber-elastic element. In contrast to the previously shown embodiment, the energy store 10 does not extend between the upper joint part 4 and the lower joint part 6, but is arranged at a distance from them. The knee joint 2 has a separate force transmission element 16 , the first end 18 of which is arranged on the upper joint part 4 and the second end 20 of which is arranged on the energy store 10 . The energy store 10 is therefore attached to the lower joint part 6 in the exemplary embodiment shown. If the upper joint part 4 is now pivoted about the pivot axis 14 relative to the lower joint part 6, the distance between the first end 18 and the energy store 10 changes and the force transmission element 16 exerts a tensile force on the energy store 10 and the second spring element contained therein in the exemplary embodiment shown out. In this way, a force is generated in the energy accumulator 10 which is transmitted from the force transmission element 16 to the upper joint part 4 . This configuration makes it possible to arrange the energy store 10 , which may take up a relatively large amount of space, at a distance from the pivot axis 12 .

In 9 forms the energy store 10 the power transmission element. The first end 18 is arranged on a carriage 22 which is different relative to the joint upper part 4 . The double arrow illustrates that the slide 22 in 9 can be shifted up and down, whereby the bias of the energy store 10 can be changed. Preferably, the carriage 22 is displaceable by a motor, not shown.

10 shows another embodiment. Both the upper joint part 4 and the lower joint part 6 have 3 fastening blocks 8 each, on which the first end 18 or the second end 20 of the energy store 10, which also forms the force transmission element in this case, can be arranged.

This also allows the prestress to be changed without the distance between the connecting line and the pivot axis 14 being changed. The predetermined swivel angle, when it is reached, the force transmission element, in the outflow example shown the energy store 10, rests against the stop 12 is not changed. Depending on the positioning of the mounting blocks 8, the predetermined swivel angle can also depend on the mounting block 8 used in each case and can change when a different mounting block 8 is selected.

This is different with the in 11 embodiment shown. A pivotable lever 24 is positioned both on the upper joint part 4 and on the lower joint part 6 , which levers are each arranged so as to be pivotable about a lever axis 26 . The lever 24 can be locked in different positions, preferably steplessly, so that it is not possible to pivot the lever 24 further about the lever axis 26 without releasing the lock. Will the two in 11 Lever 24 shown is pivoted along the arrows shown, the distance between the first end 18 and the second end 20 of the energy store 10, which are each arranged on one of the levers 24, increases. In addition, the distance between the connecting line and the pivot axis also changes, so that the predetermined pivot angle is also adjusted. By pivoting the lever 24, the lever arm, ie the distance between the elastic energy store 10 and the pivot axis, becomes smaller. The energy store However, cher 10 is more strongly biased. Reducing the lever arm leads to a reduction in the moment, and increasing the tension leads to an increase in the moment. With a clever choice, it is therefore possible to leave the total torque that is applied by the energy store unchanged if the two effects compensate each other. Then only the effective pivoting angle of the joint is changed and can be increased or decreased depending on the pivoting direction of the lever 24 .

in 12 shown embodiment of a knee joint 2, in which the first end 18 and the second end 20 of the energy storage device 10 are each arranged on a carriage 22, which, however, is different from the carriage 22 in 9 in 12 can be moved left and right. As a result, the length of the connecting line between the first end 18 and the second end 20, and thus the prestressing of the energy store 10, can be changed, for example by moving the carriage 22, on which the first end 18 is arranged, into the device and the carriage 22 , on which the second end 20 is arranged, is shifted in the other direction. In addition or as an alternative to this, the distance between the connecting line and the pivot axis can also be varied. in the in 12 The embodiment shown also has a central carriage 28 on which the energy store 10 preferably only rests but is not fastened. It can therefore be detached from the carriage 28 and rest against the stop 12 given a corresponding pivoting angle between the upper joint part 4 and the lower joint part 6 . In an alternative embodiment, the force transmission element 10 is firmly connected to the middle carriage 28 . The middle carriage 28 can also be moved to the right and left in the exemplary embodiment shown, but can be moved independently of the two carriages 22 . The middle carriage 28 is non-rotatably connected to the upper joint part 4 or the lower joint part 6 . In the embodiments shown, the stop 12 is preferably designed to be displaceable. In the illustrations shown, the stop is very close to the pivot axis 14 so that the energy store 10 runs through the pivot axis 14 when it rests against the stop 12 . However, it is advantageous if the middle carriage 28 can be moved, for example, by means of a motor, in particular an electric motor. A shift to the front, i.e. to the left in the illustrations shown, increases the applied moment and can thus support getting up from a sitting position, for example.

13 shows a similar configuration. Here, too, the first end 18 and the second end 20 are each arranged on a horizontally displaceable carriage 22 and a middle region of the energy store 10 is arranged on the middle carriage 28 . This is now free to move along the corresponding rail and loaded in both directions by a spring element 30 spring.

The knee joint 2 according to 14 differs from that according to 13 by the design of the spring loading of the middle carriage 28. In 14 a spring element 30 is present only on the side of the middle carriage facing away from the pivot axis 14 .

15 shows a knee joint in which the first end 18 and the second end 20 of the energy store 10, which also in this case again forms the force transmission element, are each arranged on a carriage 22 which can be displaced along a rail provided for this purpose. However, this rail extends differently than in the 9 and 12 until 14 neither horizontal nor vertical, but is arranged at an angle. Since the slides 22 can be loaded independently of one another, the prestressing of the energy store 10 and the distance of the energy store 10 from the pivot axis 14 can be adjusted. In this embodiment, too, the effective angle range can be set independently of the applied torque by skilful selection of the position of the carriages, as is already possible 11 was described.

16 differs from 15 in that the rails along which the carriages 22 can be displaced are designed to be curved. However, the achievable effects are the same.

In 17 on the other hand, there are 3 fastening blocks 8 each, to which the first end 18 or the second end 20 of the energy store 10 can be fastened. 18 shows a further exemplary embodiment in which the energy store 10 is arranged with the first end 18 on the upper joint part 4 and with the second end 20 on the lower joint part 6 . In this exemplary embodiment, the stop 12 is located in front of the pivot axis 14, starting from the energy store 10. As a result, the pivot angle between the upper joint part 4 and the lower joint part 6, in which the energy store 10 bears against the stop 12, is shifted to smaller swivel angles. This is also possible in the other exemplary embodiments shown and can be selected individually as required. in 18 The embodiment shown can be used to attach the energy store 10 by means of an attachment block 8 at a further point on the lower joint part 6 . The section of the energy store 10, which is located between the fastening block 8 and the second end 20, is pivoted when the lower joint part 6 relative to the joint upper part 8 is not stretched and thus does not contribute to a restoring force or torque. The effective length of the energy store 10 is determined by the section between the mounting block 8 and the first end 18 so that on the one hand the relative expansion that this effective section experiences when pivoting and on the other hand the torque generated can be adjusted.

19 shows schematically the knee joint 2, in which the first end 18 and the second end 20 of the energy store 10 can be arranged on different fastening blocks 8. This allows the bias of the energy store 10 to be adjusted. In addition, carriages 22 are arranged on both the upper joint part 4 and the lower joint part 6, to which the energy store 10 is attached and can be moved. As a result, on the one hand, the length of the section of the energy store 10 that is located between the two carriages 22 can be adjusted. If the upper carriage 22 is shifted to the left and the lower carriage 22 to the right, for example, the section between the two carriages 22 expands and the prestressing of the energy store 10 in this section increases. This is of course also possible by shifting the upper carriage 22 to the right and the lower carriage 22 to the left. In addition, however, the section of the energy store 10 that is located between the two carriages 22 is also displaced relative to the stop 12 . As a result, the pivoting angle between the upper joint part 4 and the lower joint part 6, at which the energy store 10 bears against the stop 12, can be adjusted.

In 20 the knee joint is shown, which has a further stop 32 in addition to the stop 12 in the region of the pivot axis 14 . This is preferably detachable and can be fastened to different positions on the lower joint part 6 . As a result, the energy store 10 no longer rests against the stop 12 but against the stop 32 when the lower joint part 6 is pivoted relative to the upper joint part 4 . As a result, the torque generated by the energy store 10 is not reduced, but rather maintained and increased relative to one another as the two joint parts continue to be pivoted. By choosing the position of the stop 32, the torque curve can be influenced as a function of the swivel angle. Of course, several stops 32 can also be present, which can be arranged at different positions on the upper joint part 4 and/or on the lower joint part 6, as a result of which the torque curve can be further changed. Preferably, the position of the stop 32 and thus the moment that is applied when the energy store is in contact with this stop 32 can be adjusted by the user of the device as required.

In the 21 a and 21 b an embodiment of the knee joint 2 is shown in different pivoting angles. The energy store 10 is attached to the respective joint part by means of two force transmission elements 16, the length of which allows the effective length of the energy store 10 and thus the applied torque to be adjusted. The force transmission element 16 are each arranged on a mounting block 8, which preferably defines a respective pivot axis about which the force transmission element 16 is arranged pivotably.

In the 22 a and 22 b another embodiment is shown in 2 different pivot angles. As in 20 the knee joint has a further stop 32 in addition to stop 12, this stop 32 now being selected in such a way that the energy store 10 runs around the stop 32 as shown and rests against it until a pivoting angle between the upper joint part 4 and the lower joint part 6 is reached. It is then released from this stop 32 and only rests against the stop 12 when the joint parts are pivoted further relative to one another. The result is a smaller difference in the length of the elastic energy store 10 and a smaller difference in the effective lever. Both effects ensure a smaller change in the applied torque as a function of the pivoting angle between the upper joint part 4 and the lower joint part 6.

the 23 a until 23d show another embodiment of the joint in different pivot angles. The special feature of this configuration lies in the shape of the lower joint part 6 which has a projection 34 . In a preferred embodiment, the height by which the projection 34 is in 23a protrudes upwards from the lower joint part 6, adjustable. The energy store 10 is arranged with the first end 18 on the upper joint part 4 and with the second end 20 on the lower joint part 6 . If the lower joint part 6 is now pivoted relative to the upper joint part 4 , the projection 34 also moves towards the energy store 10 .

At a pivot angle between the upper joint part 4 and the lower joint part 6, which is between the in the 23 a and 23 b shown angles, an extending moment is applied. This is an advantage in the swing phase of a step. in the in 23 b The position shown runs the elastic energy store 10 through the pivot axis, so that no moment is applied becomes. This is an advantage, for example, in the sitting position. If the lower joint part 6 is pivoted further counterclockwise about the pivot axis 14 relative to the upper joint part 4, up to the 23 c moment shown, in which the force transmission element 16 rests against the projection 34, no extending moment applied. With further pivoting of the lower joint part 6 relative to the upper joint part 4, a stretching moment is applied again because the energy store 10 stretches through contact with the projection 34 and a force is thus exerted on the lower joint part that is not directed towards the pivot axis of the joint. This situation is in 23d shown. The in the 23 a until 23d The embodiment shown consequently leads to the fact that with swivel angles which are smaller than that in 23b shown angle between the upper joint part 4 and the lower joint part 6, an extending moment is applied. This is the first angular range. With swivel angles between the in 23 b and 23 c illustrated angles, ie in a second angular range, no moment is applied. At angles that are caused by a further pivoting, ie in a third angle range, a moment is generated again.

In 24 a another configuration is shown. The first end 18 of the energy store 10 is arranged on a gear wheel 36 on the upper joint part 4 . The second end 20 of the energy store 10 is arranged on a gear wheel 36 on the lower joint part 6 . The two gears 36 are arranged to be rotatable relative to their respective joint part and mesh with a main gear 38 . This is positioned in a rotationally fixed manner, for example, on the lower joint part 6 . 24 b shows the configuration in which the lower joint part 6 is pivoted about the pivot axis 14 relative to the upper joint part 4 . Since the gears 36 are in engagement with the main gear 38, they are pivoted along the arrows and thus the energy store 10 significantly more than would be the case without gears. The course of the torque can be set as a function of the pivoting angle between the two joint parts by selecting the gears, in particular their number of teeth, diameter and peripheral shape.

Reference List

2

knee joint

4

joint upper part

6

lower joint part

8th

mounting block

10

energy storage

12

attack

14

pivot axis

16

power transmission element

18

first end

20

second end

22

Sleds

24

lever

26

lever axis

28

middle slide

30

spring element

32

attack

34

head Start

36

gear

38

main gear

40

slider

Claims (14)

Artificial knee joint (2), which a. at least one joint upper part (4), b. at least one lower joint part (6) which is arranged on one another so as to be pivotable about at least one pivot axis (14), and c. has at least one force transmission element (16) for applying a torque to at least one upper joint part (4) and/or at least one lower joint part (6), which has one end (18) attached to the upper joint part (4) and the opposite end (20) is arranged on the lower joint part (6), characterized in that the knee joint (2) has at least one stop (12) against which the force transmission element (16) bears from a predetermined pivoting angle between the upper joint part (4) and the lower joint part (6). . Knee joint (2) after claim 1 , characterized in that the stop (12) is arranged in such a way that the torque applied by the force transmission element (16) is reduced when the predetermined swivel angle is exceeded. Knee joint (2) according to one of the preceding claims, characterized in that the knee joint (2) has at least one energy store (10), preferably an elastic energy store (10), which generates a force which is transmitted by the at least one force transmission element (16) is transferred. Knee joint (2) after claim 3 , characterized in that the at least one energy store (10) is the power transmission element (16) includes, preferably forms the power transmission element (16). Knee joint (2) according to one of the preceding claims, characterized in that the force transmission element (16) runs through the pivot axis (14) when it rests against the stop (12). Knee joint (2) according to one of the preceding claims, characterized in that the force transmission element (16) is arranged detachably on the upper joint part (4) and/or on the lower joint part (6). Knee joint (2) according to one of the preceding claims, characterized in that the force transmission element (16) can be fastened at several points on the upper joint part (4) and/or on the lower joint part (6). Knee joint (2) according to one of the preceding claims, characterized in that a prestressing of the elastic energy store (10) can be adjusted. Knee joint (2) according to one of the preceding claims, characterized in that the elastic energy store (10) has a rubber-elastic element. Knee joint (2) according to one of the preceding claims, characterized in that the predetermined pivoting angle from which the force transmission element (16) rests against the stop (12) can be adjusted, preferably by changing the position of the stop (12) and/or the position of a or both ends (18,20) of the power transmission element (16) is adjustable. Knee joint (2) after claim 10 , characterized in that the knee joint (2) has at least one motor which is set up to adjust the position of the stop (12) and/or the position of one or both ends (18,20) of the force transmission element (16). Knee joint (2) according to one of the preceding claims, characterized in that the force transmission element (16) applies a torque in a first and a third angular range between the lower joint part (6) and the upper joint part (4) and in a second angular range lying between the two angular ranges Angular range applies no torque. Technical orthopedic device, in particular a knee orthosis, which has at least two knee joints (2) according to one of the preceding claims. setup after claim 10 , characterized in that the at least two knee joints (2) have different predetermined pivoting angles and/or different force transmission elements (16) and/or different energy stores (10).

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