JP2007275482A - Knee joint assist device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a knee joint assist device capable of assisting the movements such as walking of a patient with lowered knee joint function and the elderly by staunchly reproducing complicated movements of the knee joint, and being lightweight and easily wearable. <P>SOLUTION: This knee joint assist device includes a thigh-worn section 22 to be worn on a thigh region, a leg-worn section 23 to be worn on a leg region, a connecting section 24 rotatably supporting the respective knee joint side ends of the thigh-worn section 22 and the leg-worn section 23, and further a rotation mechanism section 31 rotating the knee joint side end of the leg-worn section 23 while sliding it in the front/rear direction, when the connecting section 24 rotates the leg-worn section 23 relative to the thigh-worn section 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a knee joint assisting device for assisting the operation of a knee joint whose function is reduced due to illness, accident or aging.

  The knee joint has a very complicated structure and a complicated movement in the human body. In addition, this knee joint is usually one of the organs that are most likely to fail in daily operations such as standing or walking because a load that is 4 to 5 times the weight of a human is applied. Especially for elderly people, the cartilage and meniscus of the knee joint are worn out by overloading and repeated exercises, which causes very severe knee osteoarthritis, which hinders knee extension and walking. It is getting more.

  As shown in FIG. 10, the knee joint 1 includes a bone portion composed of a femur 2, a tibia 3 and a patella 4, a cartilage composed of a meniscus, an anterior cruciate ligament 6, a posterior cruciate ligament 7, an inner collateral ligament, an outer It is formed by ligaments such as collateral ligaments. The lower end of the femur 2 protrudes rearward, and has a shape in which a number of circles having different sizes are combined. The upper surface of the tibia 3 is substantially flat, and the knee is bent and extended by rotating so that the lower part of the femur 2 rolls on the upper surface. At this time, the protruding patella 4 serves as a pulley, and the anterior cruciate ligament 6 prevents the tibia 3 from slipping forward, and the posterior cruciate ligament 7 prevents the posterior drop. Thus, the femur 2 protrudes backward, so that the knee joint 1 performs sliding and rolling motion. In order to perform such sliding and rolling motion, the femur 2 has a complicated shape and is not a simple hinge structure. For this reason, as shown in FIG. 11, the lower part of the femur 2 is rotated so as to draw a spiral locus while the rotation center 5 is shifted.

  Further, as shown in FIG. 12, the knee joint 1 is accompanied by an extension / bending / extension (direction A), which is a bending / extension movement, and an inner or outer twisting movement (direction B). If the knee straight state is 0 °, the range of motion of the extension / bend / extend motion is about 0 ° to 130 °, and the range of motion used during walking is about 0 ° to 60 °. Within this range of motion, between 10 ° and 15 ° from the start of bending of the knee, a substantially uniaxial rolling motion is performed, and thereafter, the sliding motion is gradually shifted to a sliding motion. In addition, regarding the torsional motion of the inside or outside of the knee, there is a great individual difference, so that the range of motion is not specified at present.

Conventionally, many knee braces and the like for assisting the function of the knee joint have been known and actually used for treatment and rehabilitation of patients. Among them, as a brace that is relatively easy to wear and easily assists the movement of the knee joint, for example, there is a walking joint brace for knee joint as disclosed in Patent Document 1. On the other hand, although the structure is complex, an apparatus that is closer to the actual movement of the knee joint and supports the movement of the knee joint more strongly is, for example, an electric motor that assists walking or the like as disclosed in Patent Document 2. Auxiliary devices are known.
JP 2004-167175 A JP-A-7-163607

  However, most of the conventional assistive devices and assistive devices for assisting the knee joint are configured such that the rotation axis of the knee joint is a simple single axis. For this reason, there is a problem that the sliding and rolling motion that follows the actual movement of the knee joint cannot be reproduced, and the natural bending and stretching of the knee may be hindered instead. Currently, the only way to improve such problems is for doctors, engineers, etc. to respond by improving the brace according to the patient's symptoms or making fine adjustments to the rotation axis. As an adjustment method that is actually performed, the movement axis in the basic physiological function that approximates the sliding motion of the knee joint as described above is assumed, and the axis of the orthosis is used as this movement axis. Means such as manual adjustment are taken. However, even when such an adjustment is performed, there is a problem that a shift occurs between the movement of the knee joint and the brace during use.

  A device provided with a power source as shown in Patent Document 2 has a complicated structure and the device itself becomes heavy, which may hinder walking or the like for the elderly. Moreover, since the apparatus is large, there is a problem that it cannot be easily attached and detached.

  Accordingly, an object of the present invention is to faithfully reproduce the complicated movement of the knee joint, thereby assisting a patient or an elderly person who has deteriorated function of the knee joint in walking and the like, and is lightweight and simple. The present invention provides a knee joint assisting device that can be attached to a knee.

  In order to solve the above-described problems, the knee joint assist device according to the present invention includes an upper thigh attachment portion attached to the upper thigh, a lower thigh attachment portion attached to the lower thigh, and the upper thigh attachment portion and the lower thigh attachment. Each of the knee joint side ends of the crus when the crus rotation part rotates the crus attachment part with respect to the crus attachment part. And a rotating mechanism that rotates while sliding the portion back and forth.

  According to the knee joint assisting device of the present invention, by wearing the knee joint part around the upper thigh and the lower thigh, horizontal sliding movement close to the actual movement of the knee joint and rotation accompanying bending and stretching are possible. The linked sliding rolling motion can be reproduced. For this reason, it is possible to assist natural walking and standing up without difficulty for patients with impaired knee joint function and elderly people with impaired knee joint function.

  Moreover, since the rotation mechanism part provided in the connection part is constituted by a pair of pin members and a pair of linear and arcuate long holes through which the pin members slide, it can be formed to be lightweight and compact. . For this reason, it can be attached to a patient or the like without a sense of incongruity.

  Furthermore, by providing a driving mechanism comprising a small motor and a link member in the rotation mechanism section, it is possible to assist the actual knee joint bending and stretching without unreasonableness and relieving knee pain.

  Hereinafter, embodiments of a knee joint assisting device according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows the structure of a knee joint assist device 21 of the present invention. This knee joint assisting device 21 is attached to a part of a leg part centering on the knee part of the human body, and is attached from the knee part 10 to the upper leg part 11 as shown in FIGS. Upper leg attachment part 22, lower leg attachment part 23 attached from the knee part 10 to the lower leg part 12, and a connection in which one end of the upper leg attachment part 22 and the lower leg attachment part 23 is rotatably supported in the knee part 10. And a unit 24.

  As shown in FIG. 1, the upper thigh mounting portion 22 includes a disk-shaped connecting plate 26 that abuts along the side of the knee portion 10, and a flat plate that extends from the connecting plate 26 to a part of the upper thigh portion 11. The upper thigh fixing part 25 is formed. The lower leg mounting portion 23 includes a disk-like connecting plate 28 that overlaps the connecting plate 26, and a flat plate-like lower leg fixing portion 27 that extends from the connecting plate 28 to a part of the lower leg 12. The upper thigh mounting portion 22 and the lower thigh mounting portion 23 are attached to a brace that is fixed along the surface of the leg portion, as will be described later, and are wound and fixed according to the body shape of the person to be worn by a belt or a string. .

  The connecting portion 24 is provided with a rotation mechanism portion 31 for restricting rotation of the upper thigh mounting portion 22 and the lower thigh mounting portion 23. The rotation mechanism 31 includes a first pin member 32 and a second pin member 33 erected on one connecting plate 26, and a first linear member opened horizontally on the other connecting plate 28. A long hole 34 and an arc-shaped second long hole 35, and a pressing plate 29 that fixes the tips of the first pin member 32 and the second pin member 33 and covers the connecting plate 28 are provided. . The first pin member 32 is provided at a substantially central portion of the connecting plate 26, and the second pin member is provided at one end on the outer peripheral side centering on the first pin member 32. The first long hole 34 is provided at a substantially central portion of the connecting plate 28, and the first pin member 32 is provided therethrough. The second long hole 35 is provided along the outer periphery of the connecting plate 28, and the second pin member 33 is provided therethrough.

  The first elongated hole 34 is for restricting movement when the femur 2 in the knee 10 is displaced in the horizontal direction by walking or bending and stretching. The first elongated hole 34 is a first axis that is regarded as the central axis of the femur 2. The pin member 32 is slidably held in the front-rear direction. The second elongated hole 35 is provided to guide the rotation of the femur 2 and to restrict the sliding of the first pin member 32 when bending the knee 10. The first pin member 32 is formed in an arc shape with the center.

  FIG. 2 shows the movement of the rotation mechanism 31. By forming the second long hole 35 in an arc shape so as to draw an elliptical orbit extending in the lateral direction, the second long hole 35 is interlocked with the second pin member 33 that slides along the second long hole 35, One pin member 32 slides horizontally in the first slot 34 in the right direction. By such elliptical motion of the second pin member 33 and horizontal motion by the first pin member 32, a sliding rolling motion similar to that of an actual knee joint is realized. The second elongated hole 35 is centered on the orthogonal axis Y of the first pin member 32 that is orthogonal to the horizontal movement axis X of the first pin member 32 that slides through the first elongated hole 34. Thus, it is formed in the plane in the right direction (the bending direction of the knee 10 as shown in FIGS. 3B and 4B). As described above, the second long hole 35 is set to a rotation angle within 180 ° which is the maximum bending angle of the knee portion 10 about the orthogonal axis Y, so that the second long hole 35 sits straight from an upright posture. The movement of the knee 10 up to the posture can be performed smoothly without any obstacles. The actual movement of the knee joint is a simple rotational movement without slipping between 0 ° and 15 ° when the knee starts to bend from a straight state. For example, the rotation angle of the second long hole 35 is, for example, When the angle is between 0 ° and 15 °, a perfect circular arc is formed. When the rotation angle is between 15 ° and 90 °, an elliptical arc extending in the lateral direction is formed. Approximate movement can be realized.

  Next, FIG. 3 shows an operation state during walking when the knee joint assist device 21 is worn. Fig.3 (a) shows the form of the knee-joint assistance apparatus 21 in the state in which the knee part 10 was extended. In the state where the knee is extended, the slide of the first pin member 32 is restricted at the left end portion in the first long hole 34, and the second pin member 33 is in the second long hole 35. By stopping at the upper end, the upper thigh mounting portion 22 and the lower thigh mounting portion 23 become substantially straight. Then, when the knee joint 1 is bent by a normal walking motion from the stretched state of the knee as shown in FIG. 3B, the second pin member 33 is guided in the second long hole 35 and has an arc shape. The first pin member 32 slides rightward through the first long hole 34 at the same time it descends while drawing a locus. The movable range of the second pin member 33 during such walking is in the range of 0 ° to 60 °. As a result, the knee joint 1 moves to the natural movement of the original knee joint 1 such that the femur 2 of the upper thigh 11 rotates to the right while being slightly displaced backward relative to the tibia 3 of the lower thigh 12. Combined movement can be obtained.

  Next, FIG. 4 shows an operation state when the knee joint assisting device 21 is worn and sitting on a chair or the like. FIG. 4 (a) shows the state of the rotation mechanism 31 when the knee 10 is straightened, and FIG. 4 (b) shows the knee joint 1 up to about 90 ° when sitting on a chair. The state of the rotation mechanism part 31 in the bent state is shown. In the rotation mechanism portion 31 of this embodiment, the first pin member 32 is moved to the right end of the first long hole 34 by the rotation from the straight state (0 °) of the knee portion 10 to the state of sitting on the chair (90 °). Therefore, the posture can be held for a while with the knee folded. In addition, the slide of the first pin member 32 is locked by the first elongated hole 34, and the rotational motion by the second pin member 33 is stopped accordingly, so that the muscular strength for holding the knee joint 1 is particularly reduced. When a patient or an elderly person tries to bend the knee 10, the posture cannot be maintained, and it has a role as a safety function that prevents the knee from collapsing suddenly.

  As shown in FIG. 3 and FIG. 4, according to the rotation mechanism unit 31, a movable range of 0 ° to 60 ° corresponding to the movement of a patient or the like whose function of the knee joint 1 has decreased normally walks, It is possible to assist the movement up to the range of motion of 0 ° to 90 ° according to the movement such as sitting on the chair or standing up. Further, since the first pin member 32 can be released to the right by extending the first elongated hole 34 in the right direction, the movement of the knee joint 1 up to a posture in which the first pin member 32 sits upright. It is possible to assist up to a movable range of 0 ° to 130 ° corresponding to the above.

  By defining the length of the first long hole 34 and the second long hole 35, the movement of the knee joint 1 within the length range is regulated according to each symptom of the patient and the like, and the length The movement of the knee joint 1 can be locked at both ends. As described above, the natural movement of the knee joint 1 is common in that the elliptical rotation and the deviation of the horizontal method are combined, but the first long length provided in the rotation mechanism unit 31 is the same. It is preferable that the hole 34 and the second long hole 35 are appropriately set according to the body shape of the patient or the like, age, or gender difference.

  When the first pin member 32 and the second pin member 33 are slid along the first long hole 34 and the second long hole 35, respectively, the rotation mechanism 31 acts by the frictional force. The rotation of the upper thigh mounting portion 22 and the lower thigh mounting portion 23 is restricted so as not to change suddenly or rattle. Further, if a spring member having a shape imitating the anterior cruciate ligament or the posterior cruciate ligament of the human body is interposed in the connecting portion 24 where the rotation mechanism portion 31 is provided, the rotational motion in the rotation mechanism portion 31 is reduced. It is restrained and a smooth motion along the movement of the knee joint 1 is obtained.

  When the knee joint assist device 21 is mounted on the leg, the back surface of the upper thigh mounting portion 22 is curved along the curved shape of the upper thigh portion 11 as in the knee joint assist device 41 shown in FIG. A crus rest 36 is attached, and a crus rest 37 that is curved along the curved shape of the crus 12 is attached to the back of the crus attachment 23. The upper thigh pad 36 and the lower thigh pad 37 are provided with a restraint composed of a belt 38 and a buckle 39 that are wound around and fixed to the upper thigh and the lower thigh according to the body shape.

  The knee joint assist device 41 shown in FIG. 5 has a configuration in which a drive mechanism 42 is provided in the rotation mechanism 31. Moreover, the example which mounted | wore with this knee joint auxiliary | assistance apparatus 41 is shown in FIG. The drive mechanism 42 includes a battery and a motor provided on the upper thigh mounting part 22 side, a power unit 43 including a speed reduction member for reducing the rotation speed of the motor in accordance with the operation of the knee joint 1, and the like. And a transmission mechanism for transmitting the rotational motion by the power unit 43 to the crus mounting part 23 side.

  As shown in FIGS. 7 and 8, the drive mechanism 42 of this embodiment includes a small DC motor 47 and a worm gear (not shown) for reducing the rotation of the DC motor 47 and a small power supply device in the power unit 43. It is done. The transmission mechanism is constituted by a link member 50 that is rotatably attached at one end to the rotary shaft 48 of the DC motor 47. The DC motor 47 and the power supply device are fixed to the upper end portion of the upper thigh mounting portion 22. The link member 50 includes a first arm 51 whose one end is rotatably connected to the rotary shaft 48 and a second arm 52 whose one end is rotatably connected to one end of the crus mounting portion 23. The other ends of the first arm 51 and the second arm 52 are rotatably supported by a rotatable connecting pin 53.

  According to the drive mechanism 42, the rotational torque of the DC motor 47 is decelerated by a worm gear or the like, and the rotating shaft 48 rotates clockwise or counterclockwise depending on the decelerated rotational speed. As the rotary shaft 48 rotates, the first arm 51 moves linearly along the rotation direction of the knee joint 1, and the lower arm 52 connected to the first arm 51 further moves the crus attachment portion 23. Is transmitted to. In this way, the lower leg portion 12 of the person wearing the knee joint assist device 41 can be easily lifted or extended with the help of the link member 50 that expands and contracts by the power portion 43. Adjustment of the rotational speed and direction of the DC motor 47 in the drive mechanism 42 is performed by a control unit that can be programmed according to the symptoms, body shape, age, etc. of the knee joint of the wearer. Further, by providing the control unit with a detection unit that feeds back the actual movement of the knee joint transmitted through the link member 50, it is possible to supply power according to individual differences of the wearer.

  Since the drive mechanism 42 needs to be lightened in consideration of the burden on the legs of the wearer, a lightweight and high-capacity lithium polymer battery is used for the battery, and the DC motor 47 and the link member 50 are used. It is desirable to simplify and reduce the weight of the structure. For this purpose, the battery, the control unit, etc. can be made independent from the knee joint assist device 41 via a wire or wirelessly, and can be attached to a relatively unloading part such as the torso of the person who wears it.

  As described above, according to the drive mechanism 42, the rotational torque of the DC motor 47 is converted into a linear motion through the first arm 51 and the second arm 52, so that the sliding motion in the rotational mechanism 31 is achieved. Can be reproduced continuously. Thus, it is possible to assist the patient and the elderly who cannot freely move the knee joint so that walking or the like is facilitated without imposing a burden on the patient.

  The drive mechanism 42 is configured using the link member 50 as a transmission mechanism for facilitating bending and stretching of the knee joint, but is not limited to such a configuration. For example, as shown in FIG. As described above, instead of the link member 50 shown in FIG. 8, one end is rotatably attached to the eccentric shaft 64 provided at a position away from the rotating shaft 48 of the DC motor 47, and the other end is attached to the lower leg mounting portion 23 side. It is also possible to use a crank slider 60 provided with a connecting arm 61 slidably attached to a slide groove 62 provided on the slide groove 62.

It is a disassembled perspective view of the knee joint auxiliary device according to the present invention. It is explanatory drawing which shows a motion of the rotation mechanism part of the said knee joint apparatus. It is explanatory drawing which shows a motion of the rotation mechanism part at the time of a walk. It is explanatory drawing which shows a motion of the rotation mechanism part at the time of bending of a knee. It is a perspective view of a knee joint auxiliary device provided with a power transmission mechanism. It is explanatory drawing which shows the state with which the said knee joint auxiliary | assistance apparatus was mounted | worn. It is a top view which shows one structural example of a power transmission mechanism. It is explanatory drawing which shows the structure of a deceleration mechanism. It is a top view which shows the other structural example of a power transmission mechanism. It is explanatory drawing which shows the skeleton structure of a human knee part. It is explanatory drawing which shows the motion of a femur. It is explanatory drawing which shows a motion of a knee joint part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Knee joint 2 Femur 3 Tibia 4 Patella 5 Rotation center 6 Anterior cruciate ligament 7 Back cruciate ligament 10 Knee part 11 Upper leg part 12 Lower leg part 21 Knee joint auxiliary device 22 Upper leg attachment part 23 Lower leg attachment part 24 Connection part 25 Upper leg fixing portion 26 Connecting plate 27 Lower leg fixing portion 28 Connecting plate 29 Presser plate 31 Rotating mechanism portion 32 First pin member 33 Second pin member 34 First elongated hole 35 Second elongated hole 36 Upper thigh pad portion 37 crus support part 38 belt 39 buckle 41 knee joint auxiliary device 42 drive mechanism 43 power part 47 DC motor 48 rotating shaft 50 link member 51 first arm 52 second arm 53 connecting pin 60 crank slider 61 connecting arm 62 slide groove 64 eccentricity Axis X Horizontal movement axis Y Orthogonal axis

Claims (9)

Upper leg mounting part to be mounted on the upper leg part, lower leg mounting part to be mounted on the lower leg part, and a connecting part that rotatably supports the knee joint side ends of the upper leg mounting part and the lower leg mounting part. And
A knee comprising a rotation mechanism that rotates while sliding the knee joint side end of the lower leg wearing part in the front-rear direction when the connecting part rotates the lower leg wearing part relative to the upper leg wearing part. Joint assist device. 2. The knee joint according to claim 1, wherein the rotation mechanism unit includes a pair of pin members provided in one mounting unit and a pair of long holes provided in the other mounting unit and capable of slidingly moving the pin members. Auxiliary device. The elongated hole is a linear elongated hole that slides one pin member in the front-rear direction according to the bending and stretching of the knee joint, and an arc shape for restricting the sliding of the one pin member by moving the other pin member. The knee joint assisting device according to claim 1 or 2, comprising a long hole. The knee joint assist device according to claim 2 or 3, wherein the arc-shaped elongated hole is formed in any one of left and right planes centered on an axis orthogonal to a sliding direction of a pin member that slides in the linear elongated hole. . The arc-shaped elongated hole has a length such that at least the other pin member moves from an upright position where the upper thigh and lower leg are substantially straight to a straight sitting position where the upper thigh and lower leg overlap. The knee joint auxiliary device according to claim 1, which is formed as described above. The knee joint assisting device according to claim 1, wherein the rotation mechanism unit is provided with a drive mechanism that assists the movement accompanied by rotation of the upper thigh mounting unit and the lower thigh mounting unit. The drive mechanism includes a motor provided on one of the upper thigh mounting portion and the lower thigh mounting portion, one end rotatably attached to a rotation shaft of the motor, and the other end mounted on the upper thigh mounting portion and the lower thigh mounting portion. The knee joint assisting device according to claim 6, further comprising a link member coupled to either one of the two. The link member is composed of a first arm whose one end is rotatably supported on the upper leg mounting part side to which the motor is attached, and a second arm whose one end is rotatably supported on the lower leg mounting part side, The knee joint assisting device according to claim 7, wherein the other ends of the first arm and the second arm are rotatably connected. The said drive mechanism is provided with the detection part which detects the operation amount of the knee joint which consists of the rotation amount and slide movement amount of the said rotation mechanism part, and the control part which controls rotation of the said motor based on the said operation amount. 7. The knee joint assist device according to 7.

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