Caregiving device

Abstract

This caregiving device includes: a base on which a care receiver rides; rear casters provided at a riding-direction rear section of the base; front casters provided at a front section of the base and having a larger wheel diameter than the rear casters; and intermediate casters provided between the rear casters and the front casters of the base and having a larger wheel diameter than the rear casters.

Description

Assistive devices

[0001] The present specification relates to an assistance device that assists the movement of a person being assisted.

[0002] As the aging society advances, the need for assistance devices is increasing. Many assistance devices assist the person being assisted with various movements by driving a support member that supports a part of the person's body. In some cases, assistance devices are provided with casters for mobility, allowing the person being assisted to move around while riding on the assistance device. The introduction of assistance devices reduces the physical burden on both the person being assisted and the caregiver, and also alleviates the shortage of caregivers. One technical example of this type of assistance device is disclosed in Patent Document 1.

[0003] The assistance device in Patent Document 1 includes a pair of front casters, a pair of intermediate casters, and a pair of rear casters provided on the left and right sides of a main frame, with the intermediate casters positioned outside the smallest trapezoidal area surrounding the pair of front casters and the pair of rear casters. It also discloses that the intermediate casters and the rear casters have the same diameter but are smaller than the front casters, and that the front casters have a locking function. According to this, since the intermediate casters are positioned on the outside in the left and right directions, it is said that the stability of the assistance device can be improved and interference with a bed or the like can be prevented.

[0004] International Publication No. 2021 / 210077

[0005] However, the caster configuration of the assistance device disclosed in Patent Document 1 does not always perform well. For example, on an unideal floor surface with steps or unevenness, the contact state of the multiple casters becomes unstable, reducing the mobility of the assistance device when moving over steps or unevenness. Increasing the wheel diameter of the casters would improve mobility, but this would have the disadvantage of causing interference with other devices such as wheelchairs. Furthermore, when considering an unideal floor surface, the locking function of the pair of front casters may not always be able to stabilize the stationary state of the assistance device.

[0006] Therefore, the problem to be solved in this specification is to provide an assistance device having a caster configuration that suppresses interference with other devices and improves mobility compared to conventional devices.

[0007] This specification discloses an assistance device that includes a base on which the person being assisted sits, rear casters provided at the rear of the base in the boarding direction, front casters provided at the front of the base and having a larger wheel diameter than the rear casters, and intermediate casters provided between the rear casters and front casters of the base and having a larger wheel diameter than the rear casters.

[0008] This specification also discloses an assistance device that includes a base on which a person being assisted sits, rear casters provided at the rear of the base in the boarding direction, front casters provided at the front of the base, intermediate casters provided between the rear casters and the front casters of the base, and four or more locking mechanisms provided on four or more of a plurality of casters including the rear casters, the front casters, and the intermediate casters, for locking the casters.

[0009] This specification discloses the technical idea of ​​changing "the assist device according to claim 1 or 2" in claim 4 of the original application to "the assist device according to any one of claims 1 to 3."

[0010] The disclosed assistance device is provided with intermediate casters with a larger wheel diameter than the rear casters, thereby suppressing interference with other devices such as wheelchairs and improving the device's ability to move over steps and unevenness in the floor compared to conventional devices. Furthermore, by providing a locking mechanism for each of the four or more casters, the stationary state of the assistance device can be stabilized more than conventionally on non-ideal floor surfaces with unevenness, etc.

[0011] Fig. 1 is a side view showing the overall configuration of an assistance device of an embodiment; Fig. 2 is a perspective view showing the overall configuration of the assistance device; Fig. 3 is a perspective view showing the base and foot rest member of the assistance device as viewed from below; Fig. 4 is a side view for explaining the configuration and operation of the casters in detail; Fig. 5 is a perspective view showing the overall configuration of an assistance device of a modified form;

[0012] 1. Overall Configuration of the Nursing Care Apparatus 1 of the Embodiment The overall configuration of the nursing care apparatus 1 of the embodiment will be described with reference to FIGS. 1 to 3. The arrows in the upper right corner of FIG. 1 define the front, rear, left, and right of the nursing care apparatus 1. The front of the nursing care apparatus 1 (the right side of FIG. 1) is the main traveling direction when the nursing care apparatus 1 is traveling, and the rear of the nursing care apparatus 1 (the left side of FIG. 1) is the rear of the direction in which the person being assisted boards the nursing care apparatus 1. The nursing care apparatus 1 is used for transferring a person being assisted between two locations in a room, such as between a bed and a wheelchair, or between a wheelchair and a toilet seat. The nursing care apparatus 1 can also be used for transferring a person being assisted when the two transfer locations are far apart. For example, the nursing care apparatus 1 is used for transferring a person being assisted from a room to a bathroom, dining room, toilet, etc.

[0013] The assistance device 1 supports the upper body of the person being assisted and assists them in standing up from a seated position and in sitting down from a standing position. Here, the standing position refers to a position in which the buttocks are raised above the seat surface and the legs are extended, and includes both a standing position and a semi-crouching position. In other words, the standing position includes a standing position in which the upper body is generally upright and a semi-crouching, forward-leaning position in which the upper body is leaning forward. Furthermore, the assistance device 1 has an improved caster configuration compared to conventional technology to enhance mobility. As shown in Figures 1 and 2 , the assistance device 1 is composed of a base 2, a footrest member 3, an arm member 5, a support member 6, a drive unit 7, and a control unit (not shown).

[0014] The base 2 is the portion on which the person being assisted sits. The footrest member 3, the arm member 5, and the drive unit 7 are attached to the base 2. The base 2 is formed of a pair of left and right pipe frames 21, a pair of left and right assembly frames 22, a pair of left and right front plate frames 23, and a rear plate frame 24. The pipe frames 21 are formed by bending metal pipes. The middle portions 212 of the pair of left and right pipe frames 21 extend horizontally in the front-to-rear direction at a position slightly higher than the floor surface S, and are arranged parallel to and spaced apart from each other. The front portions 211 of the pipe frames 21 are bent upward. A pair of left and right assembly frames 22 in the shape of upright plates are provided in front of the front portions 211 of the pair of pipe frames 21.

[0015] A swinging support seat 29 is provided on the upper part of each of the pair of assembly frames 22. A pair of left and right front casters 25 is provided below the pair of assembly frames 22. That is, the front casters 25 are provided at the front part of the base 2. A pair of left and right position adjustment units 281 is provided at the upper ends of the front parts 211 of the pair of pipe frames 21. The position adjustment units 281 are manual adjustment mechanisms that allow a caregiver or the like to adjust the front-to-rear position of the knee rest member 28 to suit the physique of the person being assisted, etc.

[0016] The knee pad member 28 is located above the middle section 212 of the pipe frame 21 and is the portion against which the knees of the person being assisted come into contact. By determining the knee position, the knee pad member 28 stabilizes the standing and sitting movements of the person being assisted. The knee pad member 28 is formed of a base plate 282, a knee pad main body 283, and two connecting rods 284. The base plate 282 is formed from a metal plate material so as to extend in the left-right direction and is positioned at a slight forward tilt from the vertical direction. The knee pad main body 283 is formed from an elastically deformable urethane foam or the like and is attached to the rear side of the base plate 282. The two connecting rods 284 are formed from metal bars and connect the base plate 282 to the left and right position adjustment parts 281.

[0017] As shown in FIG. 3 , the middle sections 212 of the pipe frames 21 are connected by auxiliary pipes 214 extending in the left-right direction. The auxiliary pipes 214 are made of the same material and have the same diameter as the pipe frames 21. A drive unit mounting seat 216 is provided between the left and right middle sections 212, forward of the auxiliary pipe 214. The lower part of the drive unit 7 is attached to the drive unit mounting seat 216. The rear sections 213 of the pair of left and right pipe frames 21 are formed by bending inward. The bent ends of the left and right rear sections 213 are joined together to form a single unit. The joints between the middle sections 212 and auxiliary pipes 214, and the joints between the rear sections 213, are joined by, for example, welding.

[0018] The rear plate frame 24 is formed of a metal plate-shaped member that is long in the left-right direction. The rear plate frame 24 is fixed to the upper side of the rear portion 213 of the pipe frame 21 by welding. A pair of left and right rear casters 27 is provided on the underside of the rear portion of the rear plate frame 24. In other words, the rear casters 27 are provided at the rear of the base 2 in the boarding direction.

[0019] The pair of left and right front frame plates 23 are each formed using a metal plate-shaped member. The front frame plates 23 are fixed by welding to positions near the front of the middle section 212 of the pipe frame 21 and are positioned so as to protrude outward. Caster mounting holes 231 are formed near the outside of the left and right front frame plates 23. A pair of left and right intermediate casters 26 are provided below the left and right caster mounting holes 231. In other words, the intermediate casters 26 are provided between the rear casters 27 and front casters 25 of the base 2.

[0020] The foot rest 3 is a generally thin plate-shaped member on which the care recipient places their feet. The underside of the foot rest 3 is provided with lattice-like intersecting ridges 34 to increase mechanical strength. The front edge of the foot rest 3 is provided with a pair of U-shaped attachment / detachment grooves 30 on the left and right, into which the pipe frame 21 engages. The underside of the foot rest 3 is also provided with a pair of left and right attachment / detachment sections 35, into which the pipe frame 21 engages. Each of the attachment / detachment sections 35 consists of a pair of gripping claws that are elastically deformable so as to increase or decrease the distance between their tips. The caregiver can attach the foot rest 3 to the base 2 without using tools by lowering the foot rest 3 and engaging the pipe frame 21 into the attachment / detachment grooves 30 and the attachment / detachment sections 35.

[0021] A plurality of protrusions 37 are regularly arranged on the top surface of the foot rest member 3 to prevent the feet of the person being assisted from slipping. The foot rest member 3 has a slope that decreases from the left-right central portion 31 toward the left peripheral portion 32 and the right peripheral portion 33, at least when the person being assisted does not have their feet placed on it. Therefore, even if water droplets fall on the top surface of the foot rest member 3 when the assistance device 1 is used in a bathroom or the like, the water droplets flow out of the device along the slope. Furthermore, the foot rest member 3 elastically deforms so that the slope becomes gentler when the person being assisted places their feet on it. As a result, water droplets on the foot rest member 3 automatically flow out of the device even when the person being assisted is on it. Furthermore, the gentle slope of the foot rest member 3 prevents the person being assisted from feeling any discomfort in the soles of their feet.

[0022] As shown in FIG. 1 , the arm member 5 is formed in a shape that is bent midway when viewed from the side. The exterior cover of the arm member 5 is not shown in FIGS. 1 and 2 . A swing shaft 51 is provided near the lower portion of the arm member 5. The swing shaft 51 is swingably supported by the swing support seats 29 of the left and right assembly frames 22. A stopper mechanism (not shown) is provided near the swing support seats 29 to restrict the swing angle range of the arm member 5. This allows the arm member 5 to swing upward and forward and downward and backward around the swing support seats 29 of the base 2 as the swing center. The arm member 5 swings upward and forward when the person being assisted stands up (swinging clockwise in FIG. 1 ). The arm member 5 also swings downward and backward when the person being assisted sits down.

[0023] A battery and link mechanism (not shown) are housed inside the arm member 5. The battery serves as the power source for the drive unit 7 and the control unit. A swinging member 52 is provided on the rear side of the upper part of the arm member 5. The swinging member 52 swings relative to the arm member 5. However, in the initial state before the person being assisted comes into contact with the support member 6, the swinging member 52 is restricted by the link mechanism and does not swing. The applicant of the present application has disclosed a detailed configuration example of the link mechanism in International Publication No. 2018 / 167856.

[0024] The swinging member 52 has a base plate 53 on the rear side. The base plate 53 is formed into a roughly rectangular shape using a highly rigid plate material made of metal or resin. The base plate 53 has a handle 54 on the front side. The handle 54 is formed into a roughly square frame shape and extends above the arm member 5. The handle 54 is a part that is held by the person being assisted and also by the caregiver to move the care assistance device 1.

[0025] The support member 6 is provided on the rear side of the base plate 53. The support member 6 moves relative to the base 2 while supporting a part of the body of the person being assisted. The support member 6 is composed of an upper body support section 61 and a pair of left and right side support sections 62. The upper body support section 61 is attached to the rear surface of the base plate 53. The upper body support section 61 is formed by stacking hard and soft cushioning members (not shown). The upper body support section 61 supports the upper body of the person being assisted, mainly from the chest to the abdomen area.

[0026] A pair of left and right side support sections 62 are attached to the base plate 53 and are arranged on both the left and right sides of the upper body support section 61. The side support sections 62 are formed in an L-shape that is bent at an obtuse angle. The side support sections 62 are formed by a core member and an outer peripheral member (not shown). The side support sections 62 insert into the sides of the person being assisted and support the upper body. The upper body support sections 61 and the side support sections 62 may be covered with protective covers made of cloth or leather.

[0027] The drive unit 7 drives the arm member 5 and the support member 6. A linear actuator having a fixed part 71 and a movable part 72 is used as the drive unit 7. The fixed part 71 is a stepped cylindrical member that is long in the vertical direction and has an opening at the top. The lower end of the fixed part 71 is attached to the drive unit mounting seat 216 of the base 2. The movable part 72 is a thin-diameter round rod-shaped member that is long in the vertical direction. The upper end of the movable part 72 is connected to the link mechanism. The lower part of the movable part 72 engages with the opening of the fixed part 71.

[0028] A motor 711 is provided in front of the large-diameter portion at the bottom of the fixed part 71. The motor 711 has a control unit that switches the direction of current flow to drive the movable part 72 to extend and retract. This causes the movable part 72 to extend and retract relative to the fixed part 71. A bellows cover 81 is also provided to cover the sliding portion where the fixed part 71 and the movable part 72 slide to prevent water from getting in, thereby improving the water resistance of the assistance device 1. The drive unit 7 performs a first extension action in which the assist device 1 extends from the minimum length to a predetermined intermediate length, and a second extension action in which the assist device 1 extends from the intermediate length to the maximum length.

[0029] The first extending operation of the drive unit 7 drives the support member 6 via the link mechanism to swing upward and forward. The second extending operation of the drive unit 7 drives the arm member 5 via the link mechanism to swing upward and forward. In this way, the support member 6 moves upward relative to the base 2 while also moving forward. This allows the assistance device 1 to assist the person being assisted in standing up. Furthermore, the retracting operation of the drive unit 7 causes the arm member 5 to swing downward and backward, and the support member 6 moves downward while also moving backward. This allows the assistance device 1 to assist the person being assisted in sitting down.

[0030] The control unit (not shown) is composed of an operating device and a control main unit. The operating device has an up button and a down button that operate the drive unit 7. The operating device is operated by the caregiver. The control main unit is a computer device that has a CPU and runs on software. The control main unit controls the current flowing to the motor of the drive unit 7 according to the operation information of the up button and down button. This controls the operation and stopping of the drive unit 7, as well as the switching between extension and retraction. As can be seen from the explanation so far, the arm member 5, support member 6, and drive unit 7 constitute an assistance execution unit that assists the person being assisted in standing up and sitting down.

[0031] 2. Caster Wheel Diameter Here, the caster wheel diameter (diameter) will be explained with reference to FIG. 4 . Generally, the larger the wheel diameter DF of the front caster 25, the better the mobility assistance device 1's forward movement (ability to maneuver). Furthermore, since there is little need to consider interference with other devices such as wheelchairs with the front caster 25, it is preferable that the wheel diameter DF of the front caster 25 be as large as possible. Specifically, the wheel diameter DF is preferably 90 mm or greater, and is set to 100 mm in this embodiment. This improves the mobility assistance device 1's ability to maneuver over steps and unevenness on an unideal floor surface S, and to stably maneuver on a wet and slippery floor surface S.

[0032] Next, the smaller the wheel diameter DR of the rear casters 27, the lower the footrest member 3 can be positioned, closer to the floor surface S, thereby reducing interference with other devices. Additionally, positioning the footrest member 3 lower facilitates boarding for the care recipient. The height at which the footrest member 3 is positioned is limited by the rear casters 27 located below, and in conventional configurations, it is also limited by the intermediate casters 26. In this embodiment, the front portion of the upper surface of the footrest member 3, where the feet are not placed, is formed as a protruding portion that protrudes upward, and the intermediate casters 26 are provided below the protruding portion. This allows the height of the footrest member 3's upper surface, where the feet can be placed, to be lower than the upper ends of the intermediate casters 26, without being limited by the wheel diameter DM of the intermediate casters 26. In other words, the height dimension H of the upper surface of the footrest member 3 relative to the floor surface S can be smaller than the wheel diameter DM of the intermediate casters 26.

[0033] Specifically, the wheel diameter DR of the rear caster 27 is preferably 60 mm or less, and is set to 50 mm in this embodiment. Therefore, the height dimension H of the upper surface of the footrest member 3 does not significantly exceed 50 mm. As a result, when the assistance apparatus 1 is brought close to the person being assisted M seated in the wheelchair 9, the footrest member 3 can be inserted below the pair of left and right footrests 91 of the wheelchair 9 without interfering with them. As a result, the assistance apparatus 1 can be brought close enough to the person being assisted M, making it easy for the person being assisted M to board.

[0034] Next, the wheel diameter DM of the intermediate casters 26 is set to achieve both improved traversal performance and reduced interference with other devices. Regarding improved traversal performance, on an impractical floor surface S, the front casters 25 may not always be able to perform well on the floor, and may temporarily lift off the floor surface S due to steps or unevenness. In such cases, the intermediate casters 26 assist the front casters 25 or take their place in maintaining good traversal performance. Therefore, from the perspective of traversal performance, it is preferable to increase the wheel diameter DM of the intermediate casters 26, and it may even be set to a maximum equal to the wheel diameter DF of the front casters 25.

[0035] On the other hand, to prevent interference with other devices, for example, the foot rest 3 may be inserted deep between the pair of front wheels 92 of the wheelchair 9. In this case, the protruding portion of the foot rest 3 or the intermediate caster 26 may interfere with the wheelchair 9. Therefore, from the perspective of preventing interference, it is preferable to reduce the wheel diameter DM of the intermediate caster 26, and it may be reduced to approach the wheel diameter DR of the rear caster 27. However, as disclosed in Patent Document 1, matching the wheel diameter DM to the wheel diameter DR is not compatible with improving traversal performance and therefore cannot be adopted. Furthermore, reducing the wheel diameter DM of the intermediate caster 26 is advantageous in terms of the total weight and manufacturing costs of the assistance device 1. Taking the above factors into consideration, it is preferable that the wheel diameter DM of the intermediate caster 26 be smaller than the wheel diameter DF but larger than the wheel diameter DR. In this embodiment, the wheel diameter DM is set to 75 mm.

[0036] The three wheel diameters (DF, DR, DM) mentioned above improve the mobility of the assistance device 1 while minimizing interference with other devices. Furthermore, the pair of front casters 25, the pair of middle casters 26, and the pair of rear casters 27 each have a steering function. Therefore, the assistance device 1 can move not only straight and swivel, but also move sideways and make pivot turns, enabling it to change direction and move freely even on narrow floor spaces S such as those in toilets and bathrooms.

[0037] 3. Caster Locking Mechanism Next, the caster locking mechanism will be described. Considering an imperfect floor surface S, such as unevenness or steps, the locking mechanism for the front casters disclosed in Patent Document 1 is considered insufficient in terms of the stability of the stationary state of the assistance device 1. In other words, depending on the condition of the floor surface S, the pair of front casters (left and right) may rise above the floor surface S, causing one or both of the pair of locking mechanisms to fail to perform a sufficient locking function. Furthermore, when the assistance device 1 is used in a bathroom, the casters may become slippery due to water. In these cases, the stationary state of the assistance device 1 may become unstable, potentially interfering with the movement of the person being assisted. Therefore, an improvement is needed to provide locking mechanisms for at least four of the six casters, including the front casters 25, the middle casters 26, and the rear casters 27.

[0038] In this embodiment, a pair of left and right front casters 25 are each provided with a locking mechanism 251, and a pair of left and right middle casters 26 are each provided with a locking mechanism 261. Each of the four locking mechanisms (251, 261) is a foot-operated type that the caregiver steps on to lock and unlock. Casters equipped with foot-operated locking mechanisms (251, 261) are widely available in various models and are inexpensive. This allows for greater design freedom for the care assistance device 1, and prevents costs from increasing in an embodiment in which the number of locking mechanisms (251, 261) is increased compared to conventional embodiments.

[0039] The reason why the rear casters 27 are not provided with locking mechanisms is that if the footrest member 3 comes close to or interferes with another device such as the wheelchair 9, it would be difficult to lock and unlock the rear casters 27 by stepping on them, even if they were provided with locking mechanisms. Furthermore, even if the floor surface S has steps or unevenness, it is believed that at least two of the front casters 25 and the middle casters 26 will come into contact with the floor surface S and the locking function can be achieved by the locking operation. Therefore, the locking mechanisms for the rear casters 27 are considered to be unnecessary and excessive, and are preferably omitted from the perspective of cost performance.

[0040] Furthermore, there are various types, methods, and structures of general locking mechanisms. Each of the locking mechanisms (251, 261) used in the present embodiment locks the casters against rotation and changes in orientation in a locked state after a locking operation. That is, in a locked state, the locking mechanisms (251, 261) restrict the rotation of the casters around the horizontally extending axles and restrict the rotation of the axles within a horizontal plane, preventing the orientation of the casters from changing. This eliminates the inconvenience of the casters changing orientation after a locking operation, making the unlocking operation difficult. By providing four or more locking mechanisms (251, 261), the assistance device 1 can maintain a stable stationary state on a floor surface S with steps or unevenness, since at least two of the four locking mechanisms (251, 261) perform the locking function.

[0041] The assistance device 1 of this embodiment is equipped with intermediate casters 26 having a larger wheel diameter than the rear casters 27. This allows the assistance device 1 to travel over steps and unevenness in the floor surface S more easily than ever before while suppressing interference with other devices such as the wheelchair 9. Furthermore, by providing a total of four locking mechanisms (251, 261) on the pair of front casters 25 and the pair of intermediate casters 26, the stationary state of the assistance device 1 can be made more stable than ever before on an unideal floor surface S having unevenness or the like.

[0042] 4. Modified Form Next, a modified form in which the locking mechanisms (251, 261) are modified will be described with reference to FIG. 5 . In this modified form, a locking mechanism 252 is provided on each of the pair of left and right front casters 25, and a locking mechanism 262 is provided on each of the pair of left and right intermediate casters 26. Each of the four locking mechanisms (252, 262) is a remote-operated type, unlike the foot-operated locking mechanisms (251, 261) of the embodiment. For example, the locking mechanisms (252, 262) can be locked and unlocked remotely using lock wires (253, 263).

[0043] More specifically, a lock lever 85 is provided at a suitable position on the upper front side of the arm member 5 that is easy for a caregiver to operate but difficult for a care recipient to reach. The suitable position of the lock lever 85 may be other positions. Four lock wires (253, 263) extend from the lock lever 85. Two of the lock wires 253 are operably connected to the lock mechanisms 252 of the pair of front casters 25. Another two lock wires 263 are operably connected to the lock mechanisms 262 of the pair of intermediate casters 26.

[0044] When the caregiver presses the lock lever 85 with his or her hand for the first lever operation, all four lock wires (253, 263) are pulled in a direction toward the lock lever 85. This causes the lock wires (253, 263) to be pulled in each of the four lock mechanisms (252, 262), performing a locking operation. Even if the caregiver releases his or her hand from the lock lever 85, the locked state of the lock mechanisms (252, 262) after the locking operation is maintained. In other words, an alternate type lever is used for the lock lever 85.

[0045] The caregiver's second lever operation pulls all four lock wires (253, 263) out together, away from the lock lever 85. This returns the lock wires (253, 263) to each of the four lock mechanisms (252, 262), allowing the unlocking operation to be performed. Even if the caregiver releases the lock lever 85, the unlocked state of the lock mechanisms (252, 262) remains. Thereafter, each time the lever is operated, the locking and unlocking operations of the lock mechanisms (252, 262) are alternately performed remotely. According to this modified embodiment, as with the embodiment, the stationary state of the assistance device 1 can be more stable than in the conventional embodiment. Additionally, since the four lock mechanisms (252, 262) can be operated collectively with a single lock lever 85, operability is excellent.

[0046] 5. Modifications and Applications of the Embodiments The assistance device 1 of the embodiment is suitable for use in bathrooms and shower rooms, and provides the effects of improving mobility and stabilizing the stationary state compared to conventional devices, regardless of the location of use. The assistance device 1 is provided with a pair of front casters 25, a pair of middle casters 26, and a pair of rear casters 27. However, the assistance device 1 may have a configuration with five casters, with one caster in the center instead of a pair. Furthermore, in an assistance device with five casters, locking mechanisms can be provided on three of the casters to stabilize the stationary state. Meanwhile, the assistance device may have seven or more casters and four or more locking mechanisms. In an application, a remote-controlled locking mechanism may be provided on the rear caster 27 and operated by the lock lever 85. Various other modifications and applications are possible for the embodiment and application.

[0047] 1: Assistance device 2: Base 21: Pipe frame 25: Front casters 251, 252: Locking mechanism 253: Lock wire 26: Intermediate casters 261, 262: Locking mechanism 263: Lock wire 27: Rear casters 3: Foot rest member 5: Arm member 6: Support member 7: Drive unit 71: Fixed part 72: Movable part 81: Bellows cover 85: Lock lever 9: Wheelchair DF, DM, DR: Wheel diameter H: Height dimension M: Person being assisted

Claims

1. An assistance device comprising: a base on which a person being assisted sits; rear casters provided at the rear of the base in the boarding direction; front casters provided at the front of the base and having a larger wheel diameter than the rear casters; and intermediate casters provided between the rear casters and front casters of the base and having a larger wheel diameter than the rear casters.

2. The assist device of claim 1, wherein the front casters have a larger wheel diameter than the middle casters.

3. An assistance device as described in claim 1 or 2, further comprising a foot rest member provided on the base on which the person being assisted places his / her feet, the height of the upper surface of the foot rest member being lower than the upper end of the intermediate caster.

4. The assistance device according to claim 1 or 2, wherein the rear casters, the front casters, and the middle casters are each provided in pairs on the left and right.

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