JP2010088799A - Wheelchair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheelchair for reducing the risk of fall in a state where a seat is tilted backward. <P>SOLUTION: The wheelchair includes: a pair of driving wheels to be rotated by receiving force; rear wheels to be arranged in the rear parts of the driving wheels; a frame to which the driving wheels and the rear wheels are attached and is configured to change a distance between the driving wheels and the rear wheels in response to the force to be added to a prescribed part; a driving means for adding the force to the prescribed part; the seat whose front part is on the side of the driving wheels, which is supported by the frame, and on which a user sits; and a backward tilting posture adjusting means for changing the backward tilting posture of the seat in response to the distance between the driving wheels and the rear wheels, and performing adjustment to allow a backward tilting degree to be larger in a case where the distance is larger, compared with a case where the distance is smaller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wheelchair.

It is desirable that a chair made for a disabled person such as a wheelchair has a tilt function and a reclining function depending on the obstacle. The tilt function means the function of adjusting the angle of the seat surface while maintaining the angle between the seat surface and the backrest, and the reclining function is the function of adjusting the angle of the seat surface and the backrest itself. means. By using a chair equipped with such a function for disabled people who have difficulty switching seating postures depending on their motor skills, fatigue, bed sores, anemia, etc. It is said that it is possible to prevent the occurrence of symptoms due to being forced to have the same posture. And as a literature which disclosed the invention regarding the chair carrying this kind of function, there exists patent document 1, for example. In addition, as a document disclosing an invention related to a lock structure that prevents a main body frame from rotating forward in a tilt state in which the entire main body frame is tilted backward, which is a wheelchair equipped with a tilt function, There is literature 2.
JP 2003-290294 A JP 2005-168635 A

By the way, if the wheelchair seat is tilted backward, the center of gravity of the wheelchair may move backward, which may cause the wheelchair to fall backward. This tendency becomes stronger as the seat is tilted backward. However, the technique of Patent Document 1 cannot change the stability of the wheelchair when the seat tilts backward. Further, in the technique of Patent Document 2, when the seat is tilted backward, the ground contact positions of the main wheel and the auxiliary caster do not change, and the stability of the wheelchair cannot be increased as the seat tilts backward. .
At present, wheelchairs are required to be more compact, and this is a major factor especially for indoor use. However, regarding a wheelchair having a reclining function and a tilt function, it is common to set a wide distance (wheel base) between the drive wheel and the auxiliary wheel in advance in order to ensure the stability of the vehicle body when tilting backward. For this reason, the total length of the wheelchair becomes long, which often hinders indoor use.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a wheelchair that is compact and has a reduced possibility of falling in a state where the seat is tilted backward.

  In order to solve the above-described problems, a wheelchair according to the present invention is provided with a pair of driving wheels that rotate by receiving force, a rear wheel disposed behind the driving wheel, the driving wheel, and the rear wheel. A frame configured to change a distance between the driving wheel and the rear wheel in accordance with a force applied to the predetermined part, a driving means for applying a force to the predetermined part, and a front side The seat is supported by the frame on the driving wheel side and seated by a user, and the seat is tilted backward according to the distance between the driving wheel and the rear wheel, and the distance is large. In some cases, the vehicle is provided with a back tilt posture adjusting means for adjusting the back tilt to be stronger than when the distance is small.

  Preferably, the front wheel is disposed in front of the driving wheel and configured to reciprocate between a grounding position that is in contact with the grounding surface and a grounding position that is a position above the grounding position, and the driving wheel. Front wheel position adjustment that moves the position of the front wheel according to the distance to the rear wheel, and adjusts the front wheel position to be higher when the distance is larger than when the distance is small. Means.

  Preferably, the wheel constituting the rear wheel is attached to a pivotable yoke, and the yoke is supported by the frame directly or via another member, and the drive wheel and the rear wheel Regardless of the change in distance, the distance between the ground contact point of the wheel and the projection point on the ground at the turning center may be configured to maintain a predetermined size.

  Preferably, the frame changes a distance between the driving wheel and the rear wheel according to a force applied to a predetermined portion by a link mechanism that realizes a linear motion or a pseudo linear motion, and the rear wheel The tilting posture adjusting means changes the rearward tilting posture of the seat according to the distance by connecting the link mechanism and the seat, and tilts backward when the distance is large compared to when the distance is small. It is good to adjust so that the degree of is strong.

  By using the wheelchair according to the present invention, it is possible to reduce the possibility of falling in a state where the seat is tilted backward.

1. Configuration The configuration of the wheelchair 9 according to one embodiment of the present invention will be described with reference to the drawings.
1-1. Overall Configuration FIG. 1 is a side view of a wheelchair 9 according to an embodiment of the present invention. A projection plane when the wheelchair 9 is viewed from the side surface shown in FIG. The wheelchair 9 is configured as an electric wheelchair, and the power of a motor (not shown) is transmitted to the pair of drive wheels 1. Although not shown, an operation box operated by a user seated in the wheelchair 9 is provided, and the wheelchair 9 can be moved arbitrarily such as moving forward, backward, and turning left and right by operating the operation element of the operation box. It is like that. When the wheelchair 9 is turned, the wheel 9 is turned with a difference in the amount of rotation to the left and right drive wheels 1.

  The radius of the drive wheel 1 is r1 [m]. A seat 4 on which a user is seated is disposed on the drive wheel 1. As shown in FIG. 1, the seat 41 of the seat 4 is a member for a user to sit on. The back support 42 of the seat 4 is a member that supports the back of the user sitting on the seat 41. The arm support 43 of the seat 4 is a member that supports the user's forearm. The leg support 44 of the seat 4 is a member that supports the lower leg of the user. The foot support 45 of the seat 4 is a member that supports the bottom of the user. A headrest (not shown) may be provided above the back support 42 as a member that supports the user's head.

A support member 46 is provided behind the back support 42 of the seat 4, and the link mechanism 3 is connected to the support member 46. The link mechanism 3 supports one end of the yoke 21, and the other end of the yoke 21 is provided with a bearing that receives the axle of the rear wheel 2. The rear wheel 2 is attached to the yoke 21 via this bearing. The rear wheel 2 attached in this way is disposed behind the drive wheel 1. The radius of the rear wheel 2 is r2 [m].
One end of a yoke 51 is connected to the leg support 44 of the seat 4 so that the plane S can rotate around a point P4, and a bearing that receives the axle of the front wheel 5 is provided at the other end of the yoke 51. Yes. The radius of the front wheel 5 is r5 [m].

1-2. Configuration of Link Mechanism FIG. 2 is a side view for explaining the link mechanism 3. The link 34 connected to the support member 46 is bolted so that the plane S can be rotated about the point P31. Further, the link 32 is bolted to the link 31 so that the plane S can be rotated around a point P32 that is a point located below the point P31. The link 34 is bolted to the link 32 so that the plane S can be rotated around a point P33 at the end opposite to the point P32. The link 34 and the link 33 are bolted at a point P34. That is, the link mechanism 3 constituted by these links 31 to 34 is a four-node link mechanism. 2 includes a bearing 61, a support member 62, a rod 63, a rod 64, a shaft 65, and a motor 66.

  The axle 11 of the drive wheel 1 is supported by a bearing 61 which is one of the members constituting the main body frame 6 so as to be rotatable around the point P1. The bearing 61 is fixed to a T-shaped support member 62, and the seat 41 of the seat 4 is fixed on the support member 62. That is, the seat 4 is supported by the main body frame 6 with the front side being the drive wheel 1 side. A shaft 65 which is one of the members constituting the main body frame 6 is provided at the position of the point P33 where the link 33 and the link 32 are connected. The link 33 rotates with respect to the shaft 65 around the point P33. The shaft 65 is supported as possible. A bearing portion provided at one end of a rod 64 that is a rod-like member is attached to the shaft 65, and the rod 64 is configured to be rotatable around a point P 33 that is the position of the shaft 65. .

Here, the distance between the point P31 and the point P32 is k1 [m], the distance between the point P32 and the point P33 is k2 [m], the distance between the point P33 and the point P34 is k3 [m], and the point P34 and the point P31. K4 [m], and the distance between the point P32 and the point P1 is k5 [m]. At this time, the link mechanism 3 is configured so that the following expressions (1) to (4) are established.
k2 = k5 (1)
k1 / k2≈0.15186 (2)
k3 / k2 = 0.3 (3)
k4 / k2≈0.93478 (4)

  A hollow cylindrical rod 63 extends rearward from the axle 11. The hollow inner diameter of the rod 63 is larger than the outer diameter of the rod 64, and the other end of the rod 64 opposite to the above-described bearing side is fitted into the hollow portion of the rod 63. It can slide in the direction. A rack 641 is provided on the outer peripheral surface of the rod 64 in the longitudinal direction. The rack 641 is meshed with a pinion 631 provided on the rod 63. The motor 66 is an example of a driving unit that applies a force to a predetermined portion. By applying a rotational force to the pinion 631, the power is transmitted to the rod 64 via the rack 641. Then, the rod 64 to which the power is transmitted moves in the longitudinal direction, and is pushed into or pulled out of the hollow portion of the rod 63. The depth at which the rod 64 enters the hollow portion of the rod 63 is adjusted by the movement of this machine. That is, the rod 63 and the rod 64 function as an actuator that changes the distance between the axle 11 and the shaft 65 by the power of the motor 66. The frame composed of the main body frame 6, the link mechanism 3, a post 22, and a yoke 21, which will be described later, has the driving wheel 1 and the rear wheel 2 attached thereto, and the driving wheel 1 according to the force applied to a predetermined part. It is an example of the flame | frame comprised so that the distance between the rear wheel 2 may change.

1-3. Configuration of Rear Wheel FIG. 3 is a view for explaining the rear wheel 2 of the wheelchair 9 and the members that support the rear wheel 2. The support | pillar 22 shown in FIG. 3 is a cylindrical member. The link 33 described above is a hollow cylindrical member, and is configured so that the column 22 can be stored in the hollow portion. The support column 22 is configured to be slidable in the circumferential direction around the axis AX31 that is the central axis of the link 33 with respect to the hollow portion of the link 33. A yoke 21 extends below the support column 22 in a direction away from the axis AX31 and downward as shown in FIG. That is, the yoke 21 is supported to be rotatable with respect to the link 33 via the support column 22 that slides in the hollow portion of the link 33 with the axis AX31 as the center of rotation. Note that the support column 22 and the yoke 21 may be integrated as a yoke. In this case, the yoke is directly supported by the link 33 of the link mechanism 3.

  A bearing is provided at the lower end of the yoke 21 shown in FIG. The axle of the rear wheel 2 is attached to the bearing at the lower end of the yoke 21 so as to be rotatable about the point P2. As shown in FIG. 3, the axis AX31 and the point P2 are separated by La [m]. In addition, each point obtained by projecting the point P33, which is a connection point between the link 33 and the link 32, and the point P2, which is the rotation center of the rear wheel 2, onto the axis AX31 is separated by Lb [m]. Lb + r2 = r1 is established. That is, when the axis AX31 is 90 ° with respect to the ground plane G, which is the plane on which the drive wheels 1 and the rear wheels 2 are grounded, the distance between the point P33 and the ground plane G is the radius r1 [m] of the drive wheels 1. And the same length.

2. Operation Next, the operation of the wheelchair 9 will be described with reference to the drawings.
2-1. Operation of Link Mechanism FIG. 4 shows a positional relationship between a point P1 that is the rotation center of the axle 11 and points P31 to P34 that are connection positions of the four links of the link mechanism 3 on the plane S shown in FIG. FIG. Here, the angle formed by point P32−point P1−point P33 is α [°], and the angle formed by point P1−point P33−point P34 is β [°]. The distance between the point P1 and the point P33 is a distance k6 [m].

  Since the point P32 is a position where the link 31 is fixed to the back support 42 of the seat 4 via the support member 46, the angle α [°] described above is the inclination angle of the seat 4 (in the wheelchair 9 in the tilted state, This is a numerical value corresponding to the angle formed by the back support 42 with respect to the ground plane G (hereinafter referred to as an inclination angle γ [°]). Specifically, the two are related by an equation such as γ = (constant) + α or γ = (constant) −α. FIGS. 4A, 4B, and 4C show the arrangement of the points when the angle α [°] is 30 °, 15 °, and 0 °. As shown in FIGS. 4A to 4C, even if the angle α [°] is 30 °, 15 °, or 0 °, the angle β [°] described above has a substantially constant angle. I keep it.

  FIG. 5 is a graph showing the angle β [°] and the change in the ratio ξ between the distance k6 [m] and the distance k2 [m] with respect to the change in the angle α [°]. Here, ξ = k6 / k2. As shown in FIG. 5, when the angle α [°] is 30 °, ξ = √3≈1.732, and when the angle α [°] is 0 °, ξ = 2. There is an increase of about 15.5%. On the other hand, β [°] during this period is between 89 ° and 90.5 °. That is, in the movements shown in FIGS. 4A to 4C, the axle 11 of the drive wheel 1 is quasi-linearly moved by the link mechanism 3 with respect to the link 33.

  Β [°] is an angle formed by the link 33 (that is, a line connecting the points P33 and P34) and the rod 64 and the rod 63 (that is, a line connecting the points P33 and P1). When β [°] is 90 °, the distance between the point P33 and the ground plane G is the same length as the radius r1 [m] of the drive wheel 1, so that the rod 64 and the rod 63 are connected to the ground plane G. Parallel. As described above, β [°] during this period is approximately 90 °, so that the rod 64 and the rod 63 are substantially parallel to the ground contact surface G. Accordingly, during this time, the link 33 maintains approximately 90 ° with respect to the ground plane G, so that the link mechanism 3 ensures a substantially constant turning radius of the yoke 21.

In this way, even if the distance between the drive wheel 1 and the rear wheel 2 changes due to the rod 64 sliding in the longitudinal direction of the hollow portion of the rod 63 by the power of the motor 66, the turning radius of the yoke 21 is changed. Is almost constant. Therefore, when the wheelchair 9 turns with a difference in the amount of rotation of the left and right drive wheels 1, the rear wheel 2 faces the turning direction of the wheelchair 9 with the grounding point as the turning center.
Note that k1 to k5 are preferably determined so that the above-described β [°] is within ± 5 ° with respect to 90 °, and k1 to k5 are determined to be within ± 1 °. It is most desirable.

2-2. Next, the state of the wheelchair 9 when the angle α [°] is changed will be described. Here, it is assumed that the turning of the yoke 21 with respect to the ground contact surface G is not considered, and the rear wheel 2 is maintained in a state of being disposed in front of the link 33.
FIG. 6 is a view of the state of the wheelchair 9 as viewed from the side when the angle α [°] is 30 °. As shown in FIG. 6, when the angle α [°] is 30 °, the front wheel 5 contacts the ground plane G. This contact point is designated as point P50. If the grounding point of the driving wheel 1 is a point P10 and the grounding point of the rear wheel 2 is a point P20, the distance between the driving wheel 1 and the rear wheel 2 is the distance between the point P10 and the point P20. Become. This distance is k8 [m].
On the other hand, FIG. 7 is a view of the state of the wheelchair 9 as viewed from the side when the angle α [°] is 5 °. As shown in FIG. 7, when the angle α [°] approaches 0 °, the front wheel 5 is disposed above the point P50. For example, when there is a step in front of the wheelchair 9, the user carries the wheelchair 9 on the step by tilting the seat 4 backward and lifting the front wheel 5 onto the step. Further, the distance k9 [m] between the point P10 and the point P20 shown in FIG. 7 is larger than k8 [m] shown in FIG. 6, and at this time, the degree of the backward tilt of the seat 4 is strong. . That is, even if the degree of rearward tilt of the seat 4 is increased, the wheelchair is less likely to fall backward because the distance between the wheels of the driving wheel 1 and the rear wheel 2 is adjusted to be increased.

  As described above, the wheelchair according to the present invention has a shorter overall length when traveling normally in a posture in which the seat 4 is not tilted backward, so that the turning ability can be ensured. it can. Further, since the distance between the wheels is greater when the seat 4 is tilted backward than when the seat 4 is not tilted backward, stability can be ensured.

3. Modification The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Further, the following modifications may be combined.
(Modification 1) In the above-described embodiment, the seat 4 tilts backward with the axle 11 of the drive wheel 1 as the center, but the center of the seat 4 that tilts backward may not be the axle 11. For example, the seat 4 may be tilted back and forth with any position on the surface where the seat 4 is placed on the main body frame 6 as a fulcrum. Further, the seat 4 may be attached so as to be suspended from any position of the main body frame 6. In this case, the seat 4 tilts back and forth with the attachment position as a fulcrum.

(Modification 2) In the above embodiment, the link mechanism 3 uses a four-node link, but the link mechanism 3 may use a link having four or more nodes. Moreover, in the above-mentioned embodiment, although the link mechanism 3 used the link which performs pseudo | simulation linear motion, you may use the link which carries out linear motion (strict linear motion). For example, as such a link, a mechanism of Peaucellier or a mechanism of Bricard may be used.

  Further, instead of the link mechanism 3, another motion transmission mechanism may be used. For example, a slider / crank mechanism, a motion transmission mechanism using a wire, a chain, or a rope may be used. In short, the distance between the drive wheel 1 and the rear wheel 2 is changed while keeping the turning radius of the yoke 21 substantially constant so that the yoke 21 to which the rear wheel 2 is attached can turn with respect to the ground contact surface G. I can do it.

  In the above-described embodiment, the pinion 631 of the rod 63 is engaged with the rack 641 of the rod 64 and the power of the motor 66 is transmitted to the rod 64, so that the rod 63 and the rod 64 are connected between the axle 11 and the shaft 65. However, as a configuration of this actuator, another motion transmission mechanism may be used. For example, a slider / crank mechanism, a pantograph mechanism, a motion transmission mechanism using a wire, a chain, or a rope may be used.

(Modification 3) In the above-described embodiment, the link mechanism 3 is connected to the main body frame 6 and the seat 4, so that the distance between the drive wheel 1 and the rear wheel 2 is maintained while keeping the turning radius of the yoke 21 substantially constant. In addition to the change, the backward tilt posture of the seat 4 was changed according to this distance. Specifically, the link mechanism 3 adjusts the rearward tilting posture of the seat 4 so that when the distance between the driving wheel 1 and the rear wheel 2 is large, the degree of backward tilting is stronger than when the distance is small. However, this adjustment may be performed by another mechanism.

For example, the body frame 6 of the wheelchair 9 is provided with a means for measuring the distance between the drive wheel 1 and the rear wheel 2, the seat 4 is tilted by a motor, and the tilt angle is controlled according to the measurement result of the measuring means. Also good. Here, the distance between the drive wheel 1 and the rear wheel 2 and the degree of backward tilt of the seat 4 may be proportional, may be represented by other functions, or may be represented by a continuous function. The relationship expressed may be a relationship expressed by a discrete function. When controlling the degree of backward tilt to change discretely, a table in which the distance and the degree of backward tilt are associated with each other is a ROM (Read Only Memory) or EEPROM (Electrically Erasable Programmable Read Only Memory) of the control device. The above-described control may be performed by referring to the storage device.
It should be noted that a fulcrum such as a hinge is provided at a position defined on any of the main body frames 6 and the seat 4 is fixed to the fulcrum so that the seat 4 can be tilted back and forth.

(Modification 4) In the above-described embodiment, the front wheel 5 is provided on the leg support 44 of the seat 4 via the yoke 51, and the front wheel 5 contacts the grounding surface G as the seat 4 tilts backward. However, the configuration of the front wheel 5 is not limited to this. For example, a measuring means for measuring the inclination angle of the seat 4 is provided, and the yoke 51 to which the front wheel 5 is attached is supported by the main body frame 6, and the main body frame 6 is supported at the support position according to the measurement result of the measuring means. The angle between the main body frame 6 and the yoke 51 may be changed.

(Modification 5) In the above-described embodiment, the shaft 65 of the main body frame 6 is provided at the point P33 where the link 33 and the link 32 are connected. However, the position of the shaft 65 is not limited to this. For example, the axis | shaft 65 may be provided in the position from the point P32 rather than the point P33 among the links 32. In short, when the rod 63 and the rod 64 of the main body frame 6 function as actuators, the distance between the position of the shaft 65 and the position of the axle 11 changes, and the force due to this change is transmitted to the rear wheel 2. The distance between the drive wheel 1 and the rear wheel 2 only needs to change.

(Modification 6) In the above-described embodiment, the wheelchair 9 is configured as an electric wheelchair, but may be configured as a manual wheelchair. In this case, rotational force is applied to the drive wheel 1 from the user's arm. That is, the wheelchair 9 only needs to include a pair of drive wheels that rotate by receiving force. Even when the wheelchair 9 is configured to be turned as a manual wheelchair, the wheelchair 9 may be turned with a difference in the amount of rotation to the left and right drive wheels 1.

(Modification 7) In the above-described embodiment, the support member 46 is provided behind the back support 42 of the seat 4, and the link mechanism 3 is connected to the support member 46, but the link mechanism 3 is connected. The support member 46 may be provided on another member of the seat 4 (for example, the seat 41). The link mechanism 3 may be directly connected to the seat 4.
In the above-described embodiment, the seat 4 tilts backward while maintaining the angle formed by the back support 42 and the seat 41 as the distance between the driving wheel 1 and the rear wheel 2 increases. Depending on this distance, only a part of the members constituting the seat 4 (for example, the back support 42) may be tilted backward. That is, the wheelchair 9 increases the distance between the drive wheel 1 and the rear wheel 2 even when the seat 4 is tilted rearward by the reclining function, instead of or in addition to the tilting function of the seat 4 rearward. You may do it.

It is a side view of the wheelchair concerning one embodiment of the present invention. It is a side view for demonstrating a link mechanism. It is a figure for demonstrating the member which supports the rear wheel of a wheelchair, and a rear wheel. It is the figure which showed the positional relationship of the point which is the connection position of the center of a driving wheel, and a link mechanism. It is a graph showing the change of the angle β and the ratio ξ of the distance k6 and the distance k2 with respect to the change of the angle α. It is the figure which looked at the state of a wheelchair from the side when angle alpha is 30 degrees. It is the figure which looked at the state of a wheelchair from the side when angle alpha is 5 degrees.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drive wheel, 11 ... Axle, 2 ... Rear wheel, 21 ... Yoke, 22 ... Post, 3 ... Link mechanism, 31 ... Link, 32 ... Link, 33 ... Link, 34 ... Link, 4 ... Seat, 41 ... Seat 42 ... Back support, 43 ... Arm support, 44 ... Leg support, 45 ... Foot support, 46 ... Support member, 5 ... Front wheel, 51 ... Yoke, 6 ... Body frame, 62 ... Support member, 63 ... Rod, 631 ... Pinion, 64 ... rod, 641 ... rack, 65 ... shaft, 66 ... motor, AX31 ... shaft, G ... grounding surface.

Claims (4)

A pair of drive wheels that rotate under force,
A rear wheel disposed behind the drive wheel;
The drive wheel and the rear wheel are attached, and a frame configured to change a distance between the drive wheel and the rear wheel according to a force applied to a predetermined portion;
Driving means for applying a force to the predetermined portion;
The front is the driving wheel side and is supported by the frame, and a seat on which a user is seated;
The rearward tilt posture of the seat is changed according to the distance between the driving wheel and the rear wheel, and the degree of rearward tilt is increased when the distance is large compared to when the distance is small. A wheelchair characterized by comprising a rearward tilt posture adjusting means. A front wheel that is disposed in front of the drive wheel and configured to reciprocate between a grounding position that is in contact with the grounding surface and a grounding position that is a position above the grounding position;
The position of the front wheel is moved according to the distance between the driving wheel and the rear wheel, and the position of the front wheel is adjusted to be higher when the distance is larger than when the distance is small. The wheelchair according to claim 1, further comprising front wheel position adjusting means. The wheels constituting the rear wheel are attached to a pivotable yoke, and the yoke is supported directly on the frame or via another member, and the distance between the driving wheel and the rear wheel is changed. The wheelchair according to claim 1 or 2, wherein a distance between the ground contact point of the wheel and a projection point on the ground at the turning center is maintained at a predetermined size. The frame changes a distance between the driving wheel and the rear wheel according to a force applied to a predetermined portion by a link mechanism that realizes a linear motion or a pseudo linear motion,
The backward leaning posture adjusting means changes the backward leaning posture of the seat according to the distance by connecting the link mechanism and the seat, and when the distance is large compared to when the distance is small. The wheelchair according to any one of claims 1 to 3, wherein the wheelchair is adjusted so that the degree of backward tilting is increased.

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