JP3729283B2 - Swing leg phase control method and air cylinder device for artificial leg - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for controlling the movement of a prosthetic leg with flexion and extension of the knee, particularly a femoral prosthesis, and more specifically, a control method in the swing leg phase in which the prosthetic leg is separated from the surface such as the floor during walking. The present invention relates to a technique for effectively obtaining a cushioning force in the final stage.
[0002]
BACKGROUND OF THE INVENTION
Natural walking is a dream for those who wear prosthetic legs. The natural gait is accompanied by knee flexion and extension, as well as changes in walking speed. Therefore, when a natural walk is desired, a prosthetic leg with knee flexion and extension is desired.
A prosthetic leg that meets such demands, for example, a thigh prosthesis for a person without a knee, is provided with a cylinder device at the back of the knee. The cylinder device has a reduction stroke in which the cylinder length is reduced when the knee is bent, and an extension stroke in which the cylinder length is increased when the knee is extended.
The cylinder device enables flexion and extension of the knee, but the following functions are also important for natural walking.
1 Resistance at the time of bending of the knee: The knee can be bent gently by the resistance.
2 Repulsive force after bending to the maximum: The repulsive force gives an acceleration action to swing the lower leg forward.
3 Cushioning force at the final stage of extension: The cushioning force or deceleration action makes the grounding smooth and prevents the thigh and crus from coming into strong contact.
[0003]
[First prior art for knee flexion and extension]
The first prior art is a technique described in Japanese Patent Publication No. 52-47638. FIG. 10 shows an outline of an air cylinder device used there. The air cylinder device 1010 includes a check valve 1030 inside the piston 1020 and a needle valve 1050 inside the rod 1040. When the knee bends, the needle valve 1050 performs the above-mentioned function 1 by applying flow resistance to the air flowing from the first chamber 1061 on the bottom side to the second chamber 1062 on the head side. Further, the check valve 1030 compresses the air in the first chamber 1061 on the bottom side as a result of the bending of the knee, and the above-mentioned function 2 is produced. Further, in the air cylinder device 1010, the rod 1040 has a rod large-diameter portion 1042 and an inner hole 1080 on the head side of the cylinder body 1070, and the rod large-diameter portion 1042 is formed in the inner hole 1080 at the final stage of knee extension. The air enters and the air is contained in the inner hole 1080. Contained air produces the above three functions. In such first prior art, since the valve opening of the needle valve 1050 is adjusted from the outside, control corresponding to the walking speed cannot be performed.
[0004]
[Second prior art for knee flexion and extension]
The second prior art is a technique described in Japanese Patent Application Laid-Open No. 5-228168 and relates to the proposal of the present applicant. FIG. 11A shows an outline of an air cylinder device used there. The air cylinder device 2010 also includes a check valve 2030 in the piston 2020 and a needle valve 2050 in the rod 2040. Further, in the final stage of knee extension, the rod large-diameter portion 2042 has a cylinder main body 2070. The point of entering the inner hole 2080 on the head side is the same as in the first prior art. However, in the second prior art, there is a valve opening adjusting means 2300 including a motor or the like at the end of the rod 2040, and the adjusting means 2300 adjusts the valve opening of the needle valve 2050 according to the walking speed during walking. It can be adjusted automatically. In the second prior art, in addition to the variable valve 2050, there is a fixed throttle 2090 similar to the fixed needle valve 1050 in the first prior art. The throttle 2090 is located at the head portion of the cylinder body 2070, and one opening faces the inner hole 2080 and the other opening is positioned in the middle of the flow path facing the second chamber 2062 on the head side. Accordingly, when the rod large diameter portion 2042 enters the inner hole 2080 in the final stage of knee extension, the chamber around the rod large diameter portion 2042 adjacent to the piston 2020 can function as a cushion chamber. Therefore, according to the second prior art, as shown in FIG. 11B, a repulsive force corresponding to the walking speed can be obtained by the variable needle valve 2050 , and the cushioning force can be increased by the fixed throttle 2090 . Can also be obtained. Since this cushion force is fixed, an appropriate value corresponding to the walking speed cannot be taken. As a result, it can be seen that the difference between the repulsive force and the cushioning force increases, especially when the walking speed is high (that is, when the valve opening is small), and the impact when the knee is fully extended increases.
[0005]
OBJECT OF THE INVENTION
In the present invention, the prior art described above is studied in various ways, and the technical problems found therein are taken into consideration, and the above three functions necessary for natural walking can be obtained more effectively. The purpose is to provide.
In particular, an object of the present invention is to provide a control technique capable of setting not only the repulsive force but also the cushioning force to an appropriate characteristic according to the walking speed.
Another object of the present invention is to provide an air cylinder device for a prosthetic leg that can be slimmed down without increasing the size of the prosthetic leg despite having repulsive force and cushioning force according to walking speed. To do.
[0006]
[Control characteristics required by the invention]
In this invention, as shown in FIG. 1, the characteristic which changes not only a repulsive force but cushion force according to walking speed is implement | achieved. In other words, the larger the walking speed (that is, the smaller the valve opening degree), the larger the repulsive force is required. In the present invention, the cushioning force also has a characteristic curve corresponding to the characteristic curve r of the repulsive force. achieve d. In order to enable continuous walking, it is necessary to set the repulsive force to be slightly larger than the cushioning force at the same valve opening or walking speed. The difference in magnitude between the repulsive force and the cushioning force varies depending on the person who wears the prosthetic leg. Therefore, it is preferable to provide a means for adjusting according to the individual difference on the artificial leg. As the means, it can be incorporated in a control unit for controlling the valve opening degree, or a mechanical adjustment mechanism for predefining the valve opening degree depending on the degree of screwing of the screw may be provided. Although the characteristic curve in FIG. 1 is shown as a continuous curve, it may be a curve that changes stepwise.
[0007]
[Details of the invention]
The present invention is premised on the use of a double-acting air cylinder device that strokes in accordance with knee flexion and extension. The piston of the air cylinder device divides a first chamber on the bottom side and a second chamber on the head side inside the cylindrical cylinder body. The present invention is a technique for bringing a person closer to natural walking by controlling the air flow between the first chamber and the second chamber.
According to the present invention, a variable throttle valve, which is inside the air cylinder device and generates a resistance force when the knee is bent, is basically used in order to obtain a cushioning force when the knee is extended. Has characteristics. That is, according to the present invention, after the variable throttle valve reaches a predetermined stage before the knee is fully extended during the extension stroke, a cushioning force is generated for the extension.
FIG. 2 shows one of the preferred embodiments of the present invention, and shows the arrangement of flow paths and valves that communicate between the first chamber 61 on the bottom side and the second chamber 62 on the head side. ing. 2A is an arrangement from the beginning of knee extension (ie, when the knee is bent) to a predetermined stage of extension, and FIG. 2B is an arrangement at a predetermined stage before the knee is fully extended and fully extended. It is. As shown in FIG. 2, the first and second flow paths 110 and 210 are connected in parallel between the first chamber 61 and the second chamber 62. The first flow path 110 has a check valve 30 that allows a flow from the second chamber 62 toward the first chamber 61. The second flow path 210 includes a variable throttle valve 50 that can adjust the valve opening degree according to the walking speed. Then, in the final stage of extension where the knee is fully extended, a fixed throttle 90 is connected in series to the check valve 30 of the first flow path 110 as shown in FIG. 2B. .
[0008]
As a means for adding a flow path including the fixed throttle 90 at the final stage of extension, the additional flow path including the fixed throttle 90 is connected to the first flow path 110 according to the stroke of the piston. Switching methods can be applied. For example, as in the above-described prior art, the rod large-diameter portion enters the inner hole on the head side of the cylinder body, so that the state can be switched from A to B in FIG.
[0009]
When the knee extension proceeds, the air flows from the second chamber 62 on the head side to the first chamber 61 on the bottom side. In the present invention, the first chamber 61 is arranged in parallel between the second chamber 62 and the first chamber 61. Since there are the flow path 110 and the second flow path 210, the air flow is fast and the piston slides smoothly. Therefore, the knee extension operation is quick, and the above-described action of swinging out the two lower leg portions can be effectively performed. In the final stage of extension, both the variable throttle valve 50 and the fixed throttle 90 dull the sliding of the piston and exert a cushioning force on the extension of the knee. Therefore, sufficient cushioning force can be obtained. In this case, it is preferable to arrange a restrictor in the second flow path 210 in series with the variable throttle valve 50. The restrictor restricts only the flow of air that attempts to flow from the second chamber 62 to the first chamber 61 without restricting the air flowing from the first chamber 61 to the second chamber 62. Therefore, when the valve opening is small, the restrictor generates a more appropriate cushioning force at the final stage of extension, in other words, a cushioning force that is more suitable for the wearer of the artificial leg. Therefore, as a simpler form, the fixed diaphragm 90 can be omitted by providing a restrictor.
Further, when obtaining the cushioning force against such extension, the cushioning force by the variable throttle valve 50 is mainly used, and the cushioning force is preferably adjusted by the fixed throttle 90 so as to eliminate individual differences depending on the user of the artificial leg. . As a result, the same prosthetic leg can be applied to a large number of individuals with individual differences, and the versatility of the prosthetic leg can be expanded and its cost can be reduced.
[0010]
Furthermore, in order to slim the prosthetic leg itself with flexion and extension of the knee, it is preferable to arrange the rod side extending outward from the cylinder body upward and the bottom side of the cylinder body downward. In order to realize such an arrangement, in a preferred embodiment of the present invention, the second flow path 210 is provided in the cylinder body, and a variable throttle valve is provided in the middle of the second flow path 210 at the bottom side of the cylinder body. 50 is provided.
[0011]
【Example】
(Application to thigh prosthesis)
The present invention can be applied to a prosthesis with knee flexion and extension, and a representative example is a thigh prosthesis.
FIG. 3 is a diagram showing the overall configuration of the thigh prosthesis, and FIG. 4 is an assembly detail diagram centered on the knee.
The thigh prosthesis 500 includes a plastic socket 520 corresponding to the thigh, a frame 540 that is rotatably supported by the lower end of the socket 520 and is made of aluminum, carbon fire, or the like corresponding to the lower thigh, and the frame. And a foot portion 560 supported at the lower end of the foot. The thigh prosthesis 500 includes an air cylinder device 10 for bending and extending the knee. The air cylinder device 10 includes an upper support point 550 near a support point 530 formed by pin connection between the socket 520 and the frame 540 and a lower support point 570 in the middle of the frame 540 in the longitudinal direction. Accordingly, the air cylinder device 10 has a reduction stroke in which the cylinder length is reduced when the knee is bent, and an extension stroke in which the cylinder length is increased when the knee is extended. Here, the cylinder length refers to the length between the upper support point 550 and the lower support point 570 of the air cylinder device 10. If attention is paid to each support point, the upper support point 550 is on the rod head at the tip of the rod 40 extending outward from the cylinder body 70, and the lower support point 570 is a trunnion pin on the bottom side of the cylinder body 70. It is a part of. Note that the knee portion of the thigh prosthesis 500 includes a walking speed detection mechanism 580 including a proximity switch and a knee brake mechanism 590 disposed around a support point 530.
[0012]
(First embodiment)
5 and 6 show the air cylinder device 10 according to the first embodiment. FIG. 5 corresponds to the state when the knee is bent, and FIG. 6 corresponds to the state at the final stage of knee extension.
The air cylinder device 10 includes a cylindrical cylinder body 70 made of an aluminum alloy or synthetic resin. The cylinder body 70 includes a cylinder tube 72 having a uniform inner diameter, and covers 74 and 76 located at each end of the cylinder tube 72. The rod cover 74 through which the rod 40 penetrates has an inner hole 80 having an intermediate diameter between the small diameter hole 82 and the inner diameter of the cylinder tube 72 in addition to the small diameter hole 82 for guiding the rod 40. Further, the cover 76 on the bottom side of the cylinder main body 70 has a thick portion 762, and the thick portion 762 is located at a position offset radially outward from the axis of the cylinder tube 72. Then, there is a flow path (second flow path) 210 that starts from the thick portion 762, passes through the inside of the cylinder tube 72, and opens to the inner periphery near the rod cover 74. The thick part 762 is a part for incorporating the variable throttle valve 50, and the reason why it is in a biased position is to arrange the control unit 320 for controlling the valve.
[0013]
The variable throttle valve 50 includes a poppet type valve element 52 made of stainless steel and a valve spring 54 that urges the valve element 52 in the valve opening direction. The valve body 52 receives the force of the valve spring 54 and hits the end of the shaft 342 of the drive motor 340 formed of a stepping motor. The drive motor 340 includes a screw mechanism for converting the rotational motion into the linear motion therein, and moves the shaft 342 back and forth in the axial direction by the screw mechanism. Therefore, the shaft 342 of the drive motor 340 can move the valve body 52 back and forth, whereby the valve opening degree of the variable throttle valve 50 can be adjusted. The control unit 320 includes an electronic unit including a semiconductor chip and the like, generates a control signal corresponding to the walking speed, outputs the control signal to the drive motor 340, and appropriately adjusts the valve opening degree of the variable throttle valve 50.
[0014]
On the other hand, the piston 20 made of synthetic resin fits in the cylinder tube 72 of the cylinder body 70 so as to be movable in the axial direction. The piston 20 holds a piston ring 22 on its outer periphery, thereby defining two chambers at the front and rear thereof. The chamber on the bottom side with the thick portion 762 is the first chamber 61, and the chamber on the rod cover 74 side is the second chamber 62. Here, it should be noted that when the piston 20 slides inside the cylinder tube 72, the openings 211 and 212 at both ends of the second flow path 210 are not closed by the piston 20. That is, the opening 211 facing the valve body 52 of the variable throttle valve 50 is formed by a ring-shaped protrusion 721 provided on the wall surface of the bottom portion of the cylinder body 70, and the opening 212 near the rod cover 74 is tapered. By being located on the surface 722, each is always open.
[0015]
In addition, a piston rod 40 is integrated with the piston 20, and the rod 40 penetrates the rod cover 74 and comes out of the cylinder body 70. The portion of the rod head 45 of the rod 40 located outside thereof corresponds to the upper support point 550 of the air cylinder device 10. The rod 40 has a rod large-diameter portion 42 adjacent to the piston 20, and the diameter of the large-diameter portion 42 substantially matches the diameter of the inner hole 80 on the inner periphery of the rod cover 74. In addition, lip-shaped seal rings 83 and 85 are provided in the opening portion of the inner hole 80 and the small-diameter hole 82, respectively. Therefore, as shown in FIG. 6, when the rod large diameter portion 42 enters the inner hole 80 in the final stage of knee extension, the third chamber 63 is defined in the inner hole 80.
[0016]
Attention should be paid to the piston 20 and the rod large diameter portion 42. A flow path (first flow path) 110 that starts from one opening 111 on one surface of the piston 20, penetrates the piston 20 and the rod large diameter portion 4 and reaches the other opening 112 of the small diameter portion of the rod 40 is formed. is there. The first flow path 110 has a check valve 30 in the middle thereof. The check valve 30 includes a ball valve body 32, a valve spring 34 that urges the ball valve body 32 toward the valve seat in the valve closing direction, and a support ring 36 that supports the valve spring 34. Such a check valve 30 allows air to flow from the second chamber 62 through the first flow path 110 to the first chamber 61 until the knee extension reaches the final stage, thereby causing the knee to extend smoothly. Moreover, since there is also the second flow path 210 connected in parallel to the first flow path 110 during the extension, the air flow from the second chamber 62 to the first chamber 61 flows more smoothly. However, when the rod large diameter portion 42 enters the inner hole 80 of the rod cover 74 so as to seal the inner hole 80, as shown in FIG. A third chamber 63 is defined in the hole 80, and a cushion chamber 65 is defined around the rod large diameter portion 42.
[0017]
In the present invention, the fixed throttle 90 is connected in series to the check valve 30 of the first flow path 110 at a predetermined stage before the knee is fully extended. The fixed throttle 90 is a screw-type needle valve, and the valve opening degree can be set according to the degree of screwing. Therefore, the fixed throttle 90 will be adjusted in advance and set the valve opening before using the artificial leg in consideration of individual differences. In the rod cover 74, one opening 312 communicates with the first flow path 110 through the third chamber 63, and the other opening 311 communicates with the second chamber 62 (that is, the cushion chamber 65). An additional flow path 310 is formed, and the fixed throttle 90 is arranged in the middle of the flow path 310. According to the air cylinder device 10, not only the other opening 311 of the additional flow path 310 but also the opening 212 of the second flow path 210 is opened to the cushion chamber 65. In addition to the action, a cushion action based on the variable throttle valve 50 can be obtained.
[0018]
(Second embodiment)
In the air cylinder device 710 shown in FIG. 7, the air cylinder device 10 in the first embodiment is partially changed to further improve the cushioning force characteristics. The air cylinder device 710 related to the second embodiment is provided with a restrictor 400 in series with the variable throttle valve 50 in the second flow path 210. FIG. 8A is a partial view showing the restrictor 400 in an enlarged manner. As can be seen from FIG. 8A, the restrictor 400 is mainly composed of a rubber plate 410 that is cantilevered, and the rubber plate 410 has a small through hole 420. Therefore, as shown in FIG. 8B, the restrictor 400 includes a check valve (a check valve that allows a flow from the first chamber 61 to the second chamber 62) and a check valve by the rubber plate 410. Valve) and a circuit connected in parallel. In other words, the restrictor 400 restricts only the flow from the second chamber 62 to the first chamber 61. The restrictor 400 increases the cushioning force when the walking speed is high, and realizes a more ideal cushioning characteristic.
[0019]
(Third embodiment)
In the air cylinder device 910 shown in FIG. 9, the first and second flow paths 110 and 210 are provided inside the piston 20 and the rod 40. Further, unlike the air cylinder devices 10 and 710 of the first and second embodiments, the valve opening degree adjusting means 300 including the controller unit 320 and the motor 340 is arranged at the outer end portion of the rod 40. However, the flow path configuration when the knee extension reaches the final stage is the same as in the case of the second embodiment.
[Brief description of the drawings]
FIG. 1 is a diagram showing control characteristics required by the present invention.
FIG. 2 is a diagram showing the arrangement of flow paths and valves.
FIG. 3 is a diagram showing an overall configuration of a thigh prosthesis.
FIG. 4 is an assembly detail view centering on a knee part.
FIG. 5 is a cross-sectional view showing a first embodiment of the air cylinder device, showing a state when the knee is bent.
6 is a cross-sectional view showing another state of the first embodiment of FIG. 5. FIG.
FIG. 7 is a sectional view showing a second embodiment of the air cylinder device.
FIG. 8 is a diagram for explaining a restrictor portion of the second embodiment of FIG. 7;
FIG. 9 is a sectional view showing a third embodiment of the air cylinder device.
FIG. 10 is a diagram for explaining the first prior art.
FIG. 11 is a diagram for explaining the second prior art.
[Explanation of symbols]
10, 710, 910 Air cylinder device 20 Piston 30 Check valve 40 Rod 42 Rod large diameter portion 50 Variable throttle valve 61 First chamber 62 Second chamber 63 Third chamber 65 Cushion chamber 70 Cylinder body 80 Inner hole 90 Fixed throttle 110 First flow path 210 Second flow path 310 Additional flow path 400 Restrictor 500 Thigh prosthesis

Claims (13)

  Located at the rear of the knee, there is a cylinder device that has a reduction stroke that reduces the cylinder length when the knee is bent, and an extension stroke that increases the cylinder length when the knee is extended. The cylinder device is a cylindrical cylinder body. And a piston that is inside the cylinder body and divides the cylinder body into a first chamber on the bottom side and a second chamber on the head side, one end is integral with the piston, and the other end is the head side of the cylinder body And a rod extending from the outside to the outside, and there are first and second flow paths that connect the first chamber and the second chamber, and the first flow path includes the second chamber and the first chamber. A check valve that allows a flow toward the second flow path, and a variable throttle valve in each of the second flow paths, and a method of controlling the movement of the prosthetic leg of the swing leg phase by using the check valve and the variable throttle valve, The first and second flow paths are parallel The variable throttle valve is capable of adjusting the valve opening degree according to the walking speed, and the cylinder device is configured to perform the first step at a predetermined stage before the knee is fully extended during the extension stroke. A fixed throttle is connected in series to the check valve of the flow path. When the knee is bent, the variable throttle valve generates a resistance against the bending, and when the knee is extended, the knee is at the predetermined stage. The first and second flow passages connected in parallel enable smooth extension while reaching, and after reaching the predetermined stage, the variable throttle valve and the fixed throttle generate a cushioning force against the extension. A swing phase control method for a prosthetic leg that is characteristic. The cylinder device further includes a control unit that generates a control signal according to a walking speed and a motor that is driven according to a control signal from the control unit in order to adjust a valve opening of the variable throttle valve. Item 1. The swing phase control method according to Item 1 . The prosthetic leg is a thigh prosthetic leg that includes a socket corresponding to the thigh, a frame rotatably supported by the lower end of the socket, and a frame corresponding to the lower thigh, and a foot supported by the lower end of the frame. 3. The swing phase control method according to claim 1, wherein the cylinder device includes an upper support point near a support point between the socket and the frame, and a lower support point in the middle in the longitudinal direction of the frame. 2. The swing phase control method according to claim 1 , wherein the fixed throttle includes a screw-type needle valve, and the valve opening degree is set according to the degree of screwing. Wherein in the second flow path, the variable throttle valve list in series restrictors are connected, the restrictor restricts flow only toward the first chamber from the second chamber, the swing phase control method of claim 1. The cylinder body of the cylinder device has an inner hole having a diameter smaller than the inner diameter of the other part of the cylinder body on the head side, and the rod is adjacent to the piston than the other part of the rod. A large-diameter portion that has a large diameter and enters the inner hole so as to seal the inner hole during the extension stroke, and the large-diameter portion enters the inner hole so as to seal the inner hole. but the knee is a predetermined stage before full extension, the swing phase control method of claim 1. When you get a cushion force against the extension, the variable throttle as the main cushion force by valves, by the fixed throttle, said adjusting cushioning force so as to eliminate individual differences to meet the user of the prosthesis, according to claim 1 Yu The phase control method.   An air cylinder device for a prosthetic leg that responds to flexion and extension of a knee, and is a cylindrical cylinder main body, and inside the cylinder main body, the cylinder main body is divided into a first chamber on the bottom side and a second chamber on the head side A piston that has one end integral with the piston and a rod that extends to the outside from the head side of the cylinder body, and a portion of the rod adjacent to the piston, in the final stage of knee extension A rod large-diameter portion that fits into an inner hole on the head side of the cylinder body and defines a third chamber inside the inner hole, and a flow path that penetrates the rod large-diameter portion and the piston. A first flow path having a check valve that allows a flow from the chamber to the first chamber, and when the rod large diameter section defines the third chamber, one opening passes through the third chamber and the first chamber Connected to the flow path, and The other opening is a flow path communicating with the second chamber, an additional flow path having a fixed throttle in the middle thereof, and a flow path communicating between the first chamber and the second chamber, In the middle of the above, in the air cylinder device for a prosthesis, the second flow path includes a second flow path having a variable throttle valve capable of adjusting a valve opening degree according to a walking speed of a person wearing the prosthetic leg. An air cylinder device for a prosthetic leg in the cylinder body, wherein the variable throttle valve is on the bottom side of the cylinder body in the middle of the second flow path. The prosthetic leg is a thigh prosthetic leg that includes a socket corresponding to the thigh, a frame rotatably supported by the lower end of the socket, and a frame corresponding to the lower thigh, and a foot supported by the lower end of the frame. The cylinder device includes an upper support point near the support point of the socket and the frame, and a lower support point in the middle of the longitudinal direction of the frame, and an end portion of the rod extending outward from the head portion of the cylinder body. The air cylinder device for an artificial leg according to claim 8 , wherein the upper support point and the lower support point are positioned on the bottom side of the cylinder body. The prosthetic leg air according to claim 8 , wherein the variable throttle valve extends in the same direction as the axis of the cylinder body, and the axis of the variable throttle valve is radially offset from the axis of the cylinder body. Cylinder device. The prosthetic leg air cylinder device according to claim 8 , wherein the fixed throttle includes a screw-type needle valve, and the valve opening is set according to a degree of screwing. The artificial cylinder for an artificial leg according to claim 8 , wherein a restrictor is connected in series to the variable throttle valve in the second flow path, and the restrictor restricts only a flow from the second chamber to the first chamber. The variable throttle valve includes a valve body and a valve spring that urges the valve body in a valve opening direction, and generates a control signal corresponding to the walking speed in order to adjust the valve opening degree. And a motor driven in response to a control signal from the control unit, and the motor has a shaft that moves back and forth in the axial direction by a screw mechanism, and the shaft serves as the valve body of the variable throttle valve. The air cylinder device for artificial legs according to claim 8 , which is supported.

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