JP2001299820A - Wheelchair with automatic alignment function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that an entire wheelchair is inclined to the left or right by the difference between the ground height of its left wheel and that of its right wheel, thereby the wheelchair could turn over and a riding comfortability is reduced when both wheels are put on a place with a height difference between the left and right wheels in a conventional wheelchair. SOLUTION: The wheels 2 respectively on left and right sides are respectively attached to left and right wheel frames 21 and the respective wheel frames 21 are connected by a parallel linking mechanism 4 provided with plural linking pars 41 and 42 up and down. The length direction center parts of the respective upper and lower linking bars 41 and 42 of the parallel linking mechanism 4 are respectively pivoted to a supporting frame 11 suspended from a seat frame 1 and the seat frame 1 is provide with a guide device 5 for inhibiting the vertical axis P-P of the sitting frame 1 from being tilted to the left and right for the respective wheel frames 21. Also, even when the respective left and right wheels 2 get on a step surface with the height difference between the left wheel and the right wheel, the parallel linking mechanism 4 is deformed and the seat surface part 12 of the seat frame 1 is maintained in a horizontal posture at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheelchair used by a person who has difficulty walking, and more particularly to a wheelchair which can always maintain a vertical axis of a seat frame in a vertical position regardless of the contact height of right and left wheels. The present invention relates to a wheelchair with a self-aligning function.

[0002]

2. Description of the Related Art FIG. 6 shows a rear view of a general wheelchair of this type. This conventional wheelchair has a pair of driving wheels 2 and 2 on the left and right sides of a seat frame 1, respectively. An auxiliary wheel (not shown) is provided. Further, this wheelchair is configured as a human-powered traveling type in which the rider rotates the hand rims 6, 6 attached to the respective drive wheels 2, 2 or the helper grips and pushes the handles 15, 15.

In the general wheelchair shown in FIG. 6, the distance W between the two drive wheels 2 is about 600 mm, and the height H1 from the floor F to the seat surface 12 of the seat frame ₁ is about 500 mm. ing.

[0004] In recent years, slopes are often formed in places such as roads, parks, and public buildings where there are steps to allow a wheelchair to travel as it is. When traveling in such a manner as to move in a wheelchair in parallel with the slope of the slope, the seat structure may be slightly forward (descent).
Alternatively, the seat frame 1 tilts backward (when climbing up), but since the left and right horizontal positions of the seat frame 1 are maintained, there is not much danger or anxiety.

[0005]

However, as shown in FIG. 7, the wheelchair shown in FIG.
), The longitudinal axis PP of the wheelchair is inclined by the same angle as the slope inclination angle θ with respect to the vertical line. As a result, there is a problem that a danger of falling is generated, a feeling of anxiety about falling is generated, and the riding comfort is deteriorated. Such a phenomenon that the wheelchair tilts right and left always occurs when the left and right driving wheels 2 and 2 are in contact with not only on the above-mentioned slope but also on each stepped surface.

When a person gets on this wheelchair,
When the wheelchair and the total weight of the center of gravity G of the rider is referred to as being from the floor F at a height of H ₂ about 700mm example, the overturning limit angle theta, tan .theta = driving wheel half interval W (600 ÷ 2) ÷ height of the center of gravity H ₂ (700) = approximately 0.43, and therefore θ = approximately 23 °
Becomes The overturn limit angle θ = approximately 23 ° is a considerably steep slope. Here, if a safety factor in consideration of the speed condition is estimated to be 5 to 10, the safe inclination angle for the overturn is 23 ° ÷ 5 °. 10 = approximately 5 ° to 3 ° (rounded up below the decimal point). When the inclination angle of 5 ° to 3 ° is converted into the height difference H ₃ between the left and right driving wheels 2, H ₃ = 50 mm to 2
It is about 5 mm, and such a level difference exists in many places in a current facility where a wheelchair can travel.

[0007] The present invention has the above-mentioned problem of the conventional wheelchair (the problem that the seat frame is inclined when there is a step).
In view of the above, even when the left and right wheels touch the ground with a step,
It is an object of the present invention to provide a wheelchair with an automatic centering function that can always maintain the seat surface of a seat frame in a horizontal horizontal position regardless of the level difference.

[0008]

The present invention has the following structure as means for solving the above-mentioned problems. still,
The present invention is directed to a wheelchair provided with a pair of wheels 2 and 2 on the left and right sides of a seat frame 1 as illustrated in FIGS. The seat frame 1 can be attached with a backrest seat, a seat portion seat, and the like.
Is not particularly limited. Also, the wheels 2 and 2 here
Are driving wheels, and auxiliary wheels are provided in addition to the driving wheels 2 and 2. Note that the auxiliary wheel may be at a front position or a rear position of the drive wheel 2.

In the wheelchair with self-aligning function of the present invention,
The left and right wheels 2, 2 are respectively connected to the left and right wheel frames 2.
1, 21 while the respective wheel frames 21, 21
Are connected by a parallel link mechanism 4 having a plurality of link bars 41 and 42 above and below. The parallel link mechanism 4
Only one set may be provided, but two sets of front and rear wheels may be provided between the left and right wheel frames 21 and 21 in order to improve strength and stability.

In the wheelchair with the self-centering function, the longitudinal center portions of the upper and lower link bars 41, 42 of the parallel link mechanism 4 are pivotally attached to the support frame 11 which is respectively suspended from the seat frame 1. . Furthermore, seat frame 1
Are provided with guide devices 5 and 5 that prohibit the longitudinal axis PP of the seat frame 1 from tilting left and right with respect to each of the wheel frames 21 and 21.

In this wheelchair, even when each of the left and right wheels 2 and 2 is placed on a step surface having a height difference between left and right,
The parallel link mechanism 4 is deformed and the seat surface 1 of the seat frame 1 is
2 is always maintained in the left-right horizontal posture.

That is, when the left and right wheels 2, 2 are mounted on a step surface having a difference in height between the left and right, each wheel 2, 2 is grounded on the step surface, and each wheel frame to which each wheel is mounted is mounted. Although the heights of the wheels 21 and 21 are different, the parallel link mechanism 4 is deformed at this time, and the respective wheel frames 21 and 21 are displaced while maintaining the vertical posture. Therefore, each wheel 2,
2, the vertical position PP of the seat frame 1 is also maintained in the vertical position while the vertical position of the seat frame 1 is always maintained in the vertical position irrespective of the step of the ground contact surface. Is done).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wheelchair with a self-aligning function according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 and FIG. Further, a pair of drive wheels 2 and 2 are provided on the left and right sides of the seat frame 1. Each drive wheel 2 corresponds to a wheel in the claims.

The seat frame 1 has a seating surface portion 12 on which a rider sits, a backrest portion 13, an armrest 14, handles 15 for hand pushing, and a footrest 16. The seat frame 1 has a support frame 11 for supporting the entire seat frame 1 on the lower surface of a plate member (hereinafter, referred to as a seat plate member) 12a of a seat portion 12, and a pair of left and right members constituting a guide device 5 described later. The hanging members 51, 51 are attached downward, respectively.

As shown in FIG. 4, the support frame 11 is a rectangular cylinder having an appropriate length (for example, about 250 to 300 mm) and a supporting strength. And
The support frame 11 is fixed downward at the left and right central portions of the lower surface of the seat plate 12a.

As shown in FIGS. 2 to 4, the hanging members 51 have a U-shaped cross section. The hanging members 51 are fixed downward at both left and right ends of the lower surface of the seat plate 12a with the U-shaped openings facing outward. Each of the hanging members 51, 51 has a roller 5 at each of two upper and lower positions as described later.
2, 52 are attached.

Each of the driving wheels 2 has a diameter of, for example, 600 mm.
The diameter is considerably large. Hand rims 6, 6 are attached to the outside of each of the drive wheels 2, 2, respectively.

The drive wheels 2, 2 are mounted on wheel frames 21, 21, respectively. Each wheel frame 21,
21 is, for example, a height width of about 250 mm and a front-rear width of 150 mm.
A plate having a size of about mm is used. Note that these dimensions are not particularly limited, and can be appropriately changed in design. Further, in the illustrated wheel frame 21, as shown in FIG. 1, the constricted portions are provided at the upper and lower central positions of the front and rear edges, respectively, but the rectangular wheel frame 21 may be used.

Brackets 22, 22 are mounted on the outer surfaces of the center portions of the wheel frames 21, 21, respectively. As shown in FIG. 4, an axle 23 is attached to each of the brackets 22, 22 outward. The centers (boss portions) of the drive wheels 2 and 2 are fitted into the respective axles 23. The drive wheel 2 has a connecting material such as a spoke between the rim portion and the boss portion, but the connecting material is not shown.

The base ends of the support rods 31 with the auxiliary wheels 3 attached to the distal ends are supported by the brackets 22 of the wheel frames 21 and 21, respectively. In this wheelchair, a total of four wheels, each including the drive wheel 2 and the auxiliary wheel 3, are grounded on each of the left and right sides. A free caster that can automatically change the pointing direction to the traveling direction is used for the auxiliary wheel 3.

As shown in FIG. 4, the left and right wheel frames 21 and 21 are connected by two sets of parallel link mechanisms 4 and 4, each of which includes two upper and lower link bars 41 and 42. That is, in this embodiment, the parallel link mechanism 4 attaches the left and right ends of the upper link bar 41 to the wheel frames 21 and 21 at two locations before and after the left and right wheel frames 21 and 21, respectively.
The lower link bar 42 is pivotally attached to the lower ends of the wheel frames 21 and 21 at the lower ends of the wheel frames 21 and 21 by pivots a and b, respectively. The four pivots (ad) are located at the respective tops of the parallelogram.

The left and right central portions of the upper and lower link bars 41 and 42 are pivotally connected to the upper and lower two positions of a connecting bar 43 which is oriented vertically by supporting shafts e and f, respectively. Each of these spindles e,
f is a single long one which is attached to the upper and lower two positions of the support frame 11 so as to face in the front-rear direction,
A front parallel link mechanism 4 is attached to each of the front and rear ends of each of the support shafts e and f.
And the upper and lower link bars 41, 42 of the rear parallel link mechanism 4 are pivotally connected. Therefore,
The upper link bars 41, 41 located before and after are denoted by reference characters a,
e, b, while each lower link bar 4
Reference numerals 2 and 42 are pivotally supported by three support shafts c, f, and d. The central support shafts e and f of the upper and lower link bars 41 and 42 are fixed position support shafts because they are attached to the support frame 11. In the parallel link mechanism 4, the upper and lower link bars 41, 42 are connected to the respective fixed position support shafts e,
At this time, the left and right wheel frames 21 and 21 also vertically move in a seesaw shape.
Further, since the support frame 11 is mounted in a vertical posture as viewed from the rear (or front) as shown in FIG. 2 or FIG. 5, the left and right wheel frames 21 and 21 are also mounted in a vertical direction parallel to the support frame 11. You will move up and down while maintaining your posture.

On the lower surface of the seat plate 12a of the seat frame 1, the seat frame 1 for each wheel frame 21, 21 is provided.
Guide devices 5 and 5 are provided to prevent the vertical axis PP (FIGS. 2 and 5) from tilting left and right. Each of the guide devices 5 and 5 has the same shape on the left and right.

The guide device 5 has rollers 52, 52 attached to upper and lower portions of a vertically long hanging member 51, and a pair of front and rear vertical guide walls 5 on the inner surface of the wheel frame 21.
8, 58 are provided. The hanging member 51 is a cross section having a U shape and a predetermined length. As shown in FIG. 3, the upper and lower rollers 52 are respectively mounted on the front and rear outer surfaces of the hanging member 51 in pairs.
In addition, the pair of rollers 52, 52 has a single roller shaft 53.
Attached to both ends. The roller shaft 53 is provided with the hanging material 5.
It is movable left and right in a long hole 54 formed in the side wall of the first side and facing left and right. Further, the roller shaft 53 is urged outward by a spring 55. The spring 55 is connected to the rollers 52, 5 at both ends of the roller shaft 53.
2 is always pressed against the inner surface of the wheel frame 21. And each roller 5
Each of the hanging members 51, 51 to which the seat members 2, 52 are attached,
The lower surface 2a is fixed downward at the left and right ends thereof, respectively.

As shown in FIG. 3, the vertical guide walls 58, 58 formed on the inner surface of the wheel frame 21 are installed so as to guide the outer surfaces of the pair of front and rear rollers 52, 52. That is, the guide walls 58, 58 position the hanging member 51 and the wheel frame 21 in the front-rear direction so that both (51 and 21) do not rattle back and forth.

As shown in FIG. 3, the guide devices 5, 5 are assembled such that the rollers 52, 52 of the hanging members 51, 51 on each side are in contact with the inner surfaces of the wheel frames 21, 21, respectively. In this assembled state, the rollers 52, 52 are pressed against the inner surface of the wheel frame 21 by the springs 55, and the outer surfaces of the front and rear rollers 52, 52 are guided by guide walls 58, 58, respectively. .

The wheelchair according to this embodiment can be run by the occupant rotating the hand rims 6 and 6 by himself / herself, or by the caregiver holding the handles 15 and 15 and pushing by hand. Also, when traveling on a flat surface,
As shown in FIGS. 1 and 2, a total of four wheels including two drive wheels 2 and two auxiliary wheels 3 are in contact with the ground, and in this state, the longitudinal axis PP of the seat frame 1 is viewed from the rear (or front). Is oriented vertically.

Then, as shown in FIG. 5, when the wheelchair rides on the sloped floor F in a direction intersecting (for example, orthogonally) to the inclination direction, the left and right wheels 2, 2
Although the auxiliary wheels 3 (including the auxiliary wheels 3) are grounded with a difference in height from side to side, the respective wheel frames 21 supporting the respective wheels 2, 2
21 is vertically displaced by the parallel link mechanism 4 while maintaining the vertical posture. That is, the upper and lower link bars 41, 42
Is tilted in a seesaw shape about the fixed position supporting shafts e and f supporting the center of each link bar, so that each wheel frame 21, 21 and each wheel (2, 3) are vertically parallel. It will be displaced up and down while maintaining the posture. Further, at this time, as shown in FIG. 5, the line connecting the fixed position support shafts e and f (the directivity direction of the support frame 11) always keeps a vertical posture when viewed from the rear (or the front). . As described above, when the support frame 11 maintains the vertical posture, even if the left and right wheels 2 and 2 touch the ground with a height difference between the left and right, the longitudinal axis PP of the seat frame 1 also maintains the vertical posture, The center of gravity of the total weight of the seat frame 1 and the passenger does not deviate left and right. Therefore, even when moving in a direction crossing the slope-shaped floor F on a wheelchair, the seat frame 1 does not incline left and right, so that there is no danger of falling and the riding comfort does not deteriorate. still,
The form in which the left and right wheels touch the ground with a height difference is not only when crossing a slope, for example, when only one of the left and right wheels rides on a step like a sill, only one of the left and right wheels is in a groove When the vehicle enters the road, it may occur when the vehicle travels on a bumpy road having large irregularities. In such a case, the vertical axis PP of the seat frame 1 is maintained in the vertical posture as described above.

When the wheel frames 21 and 21 are displaced vertically, the rollers 5 of the left and right guide devices 5
The inner surfaces of the wheel frames 21 and 21 respectively slide in a press-contact state with respect to 2 and 52 (there are two upper and lower locations) (rollers are rolled). Accordingly, each of the guide devices 5, 5 exhibits a guide function of maintaining the seat frame 1 in a vertical posture.

As shown in FIG. 2, when the left and right wheels 2, 2 are in contact with the floor F of the same height, the upper and lower link bars 41, 42 of the parallel link mechanism 4 are maintained in a horizontal posture. On the other hand, as shown in FIG. 5, when the left and right wheels 2, 2 are in contact with the ground with a height difference, the parallel link mechanism 4
The upper and lower link bars 41, 42 tilt. When the link bars 41 and 42 are in the horizontal posture and the inclined posture, the distance between the left and right wheel frames 21 and 21 changes, though very slightly. That is, the two-wheel frame 2 in the horizontal state of the link bar in FIG.
The interval between 1 and 21 becomes slightly wider. By the way, in the guide devices 5 and 5 of this embodiment, each wheel frame 21,
Since the roller shafts 53 of the rollers 52, 52,... In contact with the inner surface of the roller 21 can be advanced and retracted in the elongated holes 54 and urged outward by springs 55 (FIG. 3), the wheel frames 21, 21 are formed. The change in the interval between the rollers 52 and 5
2 ... can be followed. Also, each roller 52,
Are constantly pressed against the inner surface of the wheel frame by the biasing force of the spring 55, so that even if the above-mentioned change in the interval occurs, the rollers 52, 52,.
No backlash occurs between them.

[0031]

The wheelchair with self-aligning function of the present invention has the following effects.

The present invention relates to a wheelchair provided with a pair of wheels 2 on the left and right sides of a seat frame 1. In a wheelchair, the wheel frames 21 and 21 on which the left and right wheels 2 and 2 are mounted are vertically connected by a plurality of links. The parallel link mechanism 4 having the bars 41 and 42 is connected to each other, and the longitudinal center portions of the upper and lower link bars 41 and 42 of the parallel link mechanism 4 are respectively connected to the seat frame 1.
And pivotally attached to the support frame 11 suspended from
The seat frame 1 is provided with guide devices 5 and 5 that prohibit the longitudinal axis PP of the seat frame 1 from tilting left and right with respect to each of the wheel frames 21 and 21.

In the wheelchair with the self-centering function of the present invention, even if the left and right wheels 2 and 2 touch the ground with a height difference between the left and right, the seat frame 1 is deformed by the parallel link mechanism 4.
Is always maintained in a vertical posture. Therefore, even when the user moves on the wheelchair in a direction crossing, for example, a slope-shaped floor F, the seat frame 1 does not incline left and right, so that there is no danger of falling and the ride comfort is not deteriorated.

[Brief description of the drawings]

FIG. 1 is a side view of a wheelchair with an automatic centering function according to an embodiment of the present application.

FIG. 2 is a right side view (rear view of a wheelchair) of FIG.

FIG. 3 is an enlarged sectional view corresponding to the view taken along the line III-III in FIG. 2;

FIG. 4 is an enlarged perspective view of a parallel link mechanism used in the wheelchair of FIG. 1;

FIG. 5 is a state change diagram of FIG. 2;

FIG. 6 is a rear view of a conventional wheelchair.

FIG. 7 is a state change diagram of FIG. 6;

[Explanation of symbols]

1 is a seat frame, 2 is a wheel (drive wheel), 3 is an auxiliary wheel,
4 is a parallel link mechanism, 5 is a guide device, 11 is a support frame, 12 is a seat surface, 12a is a seat plate, 21 is a wheel frame, 41 is an upper link bar, 42 is a lower link bar, 4
3 is a connection bar, F is a floor, and a to f are spindles.

Claims (1)

[Claims] 1. A wheelchair having a pair of wheels (2, 2) on the left and right sides of a seat frame (1), wherein the left and right wheels (2, 2) are respectively connected to the left and right wheel frames (21, 21). Attachment, Each wheel frame (21, 21) is connected by a parallel link mechanism (4) having a plurality of upper and lower link bars (41, 42), and the upper and lower link bars (41, 4) of the parallel link mechanism (4) are connected.
2) The center part in the length direction is pivotally attached to a support frame (11) suspended from the seat frame (1), and each wheel frame (21, 21) is attached to the seat frame (1).
And a guide device (5, 5) for preventing the longitudinal axis (PP) of the seat frame (1) from tilting to the left and right is provided, and the left and right wheels (2, 2) are set to the left and right. The parallel link mechanism (4) is deformed so that the seat surface (12) of the seat frame (1) is always maintained in a horizontal posture even when riding on a step surface having a height difference. Wheelchair with self-aligning function.