JP2003079671A - Front-wheel supporting mechanism for wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front-wheel supporting mechanism for wheelchair that can relieve the vibrations and shocks received by a person riding on a wheelchair from recessing and projecting parts or obstacles on the surface of a road and can reduce the sensation of fear felt by the person for overturning. SOLUTION: A suspension mechanism 5 is installed to the lower end section of the body frame of the wheelchair through a connecting section 2, a planar rotating section 3, and a supporting member 41. The mechanism 5 is provided with a crank shaft structure 50 and a magnet gear. The structure 50 is composed of a horizontal bearing shaft 51 rotatably supported by the lower end section of the supporting member 41, an axle 52 rotatably supporting front wheels 1, and an arm 53 which is positioned perpendicularly to the bearing shaft 51 and axle 52 to connect one end of the shaft 51 to that of the axle 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support mechanism for supporting front wheels of a wheelchair.

[0002]

2. Description of the Related Art Wheelchairs are a substitute for people who have a lower handicap due to an accident, illness, or aging. Wheelchairs were mainly used indoors, but with the progress of barrier-free society, they have also been used widely outdoors. Along with this, vibrations and shocks that the occupant receives from road surface irregularities and obstacles have become a major problem. Vibrations and shocks cause further damage to the health of handicapped passengers. In a conventional wheelchair, the front wheels made of solid tires having a small diameter are simply supported by the vehicle body frame as they are. Therefore, the above-mentioned vibrations and shocks are hardly alleviated. Therefore, in recent years, a mechanism 10 for supporting the front wheel 1 via a spring 11 as shown in FIG. 9A has been adopted. By the way, in a wheelchair, the distance between the front wheel and the rear wheel is narrow. Further, when the occupant gets on the wheelchair, the center of gravity becomes high because the head is heavy. Therefore,
Wheelchairs with occupants are by no means stable.

[0003]

In the wheelchair that employs the mechanism 10, if the spring 11 is soft, the following problems occur. If the occupant deviates from the center of the wheelchair, the spring 11 contracts and the wheelchair tilts. When an occupant leans to pick up an object on the road surface 3, the spring 11 contracts and the wheelchair tilts. In FIG. 9, the wheelchair runs in the direction of arrow A, and the front wheel 1
However, as shown in (b), when it collides with the obstacle 61, the spring 11 contracts and the front side of the wheelchair sinks by H1, which causes the occupant to lean forward. Thus, when the spring 11 is soft, the occupant feels fear of falling. On the contrary, when the spring 11 is hard, the vibrations and shocks that the occupant receives due to the unevenness of the road surface are hardly alleviated.

It is an object of the present invention to provide a front wheel support mechanism for a wheelchair, which can alleviate vibrations and impacts on the occupant caused by road surface irregularities and obstacles and reduce the fear of the occupant's fall. .

[0005]

The invention according to claim 1 is
A support mechanism for supporting a front wheel of a wheelchair includes a suspension mechanism for rotatably supporting the front wheel at a lower end portion of a vehicle body frame, the suspension mechanism includes a crankshaft structure, and a crankshaft structure, A horizontal support shaft that is rotatably supported at the lower end of the body frame, an axle that rotatably supports the front wheels, a horizontal support shaft and one end of the horizontal support shaft that is positioned at right angles to the axle and one end of the axle. It is characterized by consisting of an arm connecting with and.

According to a second aspect of the present invention, in the first aspect of the present invention, the suspension mechanism includes control means for controlling the rotational operation of the horizontal support shaft, and the control means is such that the axle has the horizontal support shaft. The control is performed so that it is easier to adopt the state of being vertically below than the state of being vertically above.

According to a third aspect of the present invention, in the first aspect of the present invention, a support member is connected to a lower end portion of the vehicle body frame, and the support member is vertically swingable and upward. Of the elastic member is subjected to the resistance of the elastic body, and the horizontal support shaft is rotatably supported by the lower end portion of the support member.

According to a fourth aspect of the present invention, in the invention according to the third aspect, the support member is rotatable about the vertical axis.

[0009]

1 is a partial vertical cross-sectional side view of a wheelchair front wheel support mechanism of the present invention, and FIG. 2 is a partial vertical cross-sectional front view of the same. This support mechanism includes a connecting portion 2, a plane rotating portion 3,
It is composed of a swing mechanism 4 and a suspension mechanism 5.

The connecting portion 2 has a vertical rotating shaft 23 in a cylindrical body 21 via a ball bearing 22. The plane rotation unit 3 is fixed to the lower end of the vertical rotation shaft 23. As a result, the plane rotation unit 3 rotates in a plane with the rotation of the vertical rotation shaft 23.

The swing mechanism 4 comprises a support member 41 and a spring 42. The upper end of the supporting member 41 is rotatably coupled to the plane rotating portion 3 by a horizontal shaft 43, so that the supporting member 41 swings in the vertical direction. The support member 41 is provided so as to be inclined rearward. The support member 41 is formed with a rearward protruding portion 411. Spring 4
2 is provided between the rearward protruding portion 411 and the plane rotating portion 3, and resists when the support member 41 swings upward.

A suspension mechanism 5 for rotatably supporting the front wheel 1 is provided at the lower end of the support member 41.
The suspension mechanism 5 includes a crankshaft structure 50. The crankshaft structure 50 includes a horizontal support shaft 51 rotatably supported by a lower end portion of a support member 41, an axle 52 rotatably supporting the front wheel 1, and a right angle with respect to the horizontal support shaft 51 and the axle 52. Located at one end of the horizontal support shaft 51 and the axle 52
And an arm 53 connecting one end of the. The horizontal support shaft 51 is supported by the support member 41 via a ball bearing 511. The axle 52 is supported by the front wheel 1 via a ball bearing 521. FIG. 3 is a perspective view of the crankshaft structure 50.

The suspension mechanism 5 further comprises control means for controlling the rotational operation of the horizontal support shaft 51. The control means comprises a magnet gear 55. In the magnet gear 55, the axle 52 of the crankshaft structure 50 is the horizontal support shaft 51.
As shown in FIG. 4 (a) when it is vertically above the
The S pole and N pole on the horizontal support shaft 51 side and the S pole and N pole on the support member 41 side are provided such that the same poles face each other. Therefore, the magnet gear 55 acts so that the relationship between the horizontal support shaft 51 and the support member 41 is half-turned from the state shown in FIG. 4A to the state shown in FIG. 4B by the arrow E.

Next, the operation of the support mechanism having the above structure will be described. 5A shows a state before the collision, and FIG. 5B shows a state at the time of the collision. As shown in FIG. 5, when the wheelchair travels in the direction of arrow A and the front wheel 1 collides with the obstacle 61 on the road surface 6, the crankshaft structure 50 rotates backward around the horizontal support shaft 51 (direction of arrow B). Since it moves, the impact f received from the obstacle 61 is released to the rear, and at the same time, the support member 41 swings upward (in the direction of arrow C) around the horizontal axis 43 against the spring 42. The impact f is also released upward. In addition, at the time of a collision, the above-described operation causes the support member 41 to move forward with respect to the front wheel 1, so that the displacement amount S2 in the traveling direction at the time of the collision is as shown in FIG.
Is longer than S1 in the conventional case. When it becomes longer, the momentary shock is alleviated. Therefore, the impact that the occupant receives when the vehicle collides with the obstacle 61 is mitigated. When traveling over bumps and dips on the road surface 6, vibrations and impacts on the occupant are alleviated by the same operation. Therefore, good riding comfort can be obtained.

Further, as described above, the front wheel 1 is the obstacle 6
1, the crankshaft structure 50 rotates around the horizontal support shaft 51 in the arrow B direction, and the support member 41 swings around the horizontal shaft 43 in the arrow C direction. Will cancel out the vertical fluctuations of the plane rotating part 3, and the sinking amount H2 of the plane rotating part 3 will be much smaller than H1 in the conventional case of FIG. Therefore, the curling before the collision is suppressed.

Further, as shown in FIG. 6, when the front wheel 1 descends the large step 62, the suspension mechanism 5 operates as follows. In the state of FIG. 6A, the magnet gear 55 is in the state of FIG. Therefore, the magnet gear 55 tries to rotate the crankshaft structure 50 around the horizontal support shaft 51. In such a state, when the wheelchair runs in the direction of arrow A and the front wheels 1 pass the step 62, at that moment,
As shown in (b), the crankshaft structure 50 rotates around the horizontal support shaft 51, and the axle 52 is positioned vertically below the horizontal support shaft 51. That is, the magnet gear 55 is in the state shown in FIG. When the front wheel 1 lands on the road surface 6, the crankshaft structure 50 rotates around the horizontal support shaft 51 while resisting the force of the magnet gear 55,
As shown in (c), the axle 52 is positioned vertically above the horizontal support shaft 51. As described above, when the front wheel 1 descends from the step 62, the crankshaft structure 50 is forcedly and instantaneously changed from the state (a) to the state (b) by the action of the magnet gear 55, and the state (c). In this case, the front wheel 1 rotates about the horizontal support shaft 51 while resisting the force of the magnet gear 55.
The impact on the occupant when getting off 2 is alleviated.

In the magnet gear 55, the front wheel 1 has an obstacle 6
In the case of colliding with 1 or over bumps,
The crankshaft structure 50 functions so as to exhibit the above-described operation well. That is, the magnet gear 55 promotes the rearward rotation of the crankshaft structure 50 around the horizontal support shaft 51, and at the same time, the rotated crankshaft structure 50.
Acts to prevent the
The above-described operation of the crankshaft structure 50 is satisfactorily exhibited, and shock and vibration are further alleviated.

As described above, in the support mechanism having the above structure, the impact and vibration received by the occupant from the obstacle 61, the unevenness, and the step 62 are alleviated, so that a good riding comfort can be obtained. Moreover, since the frontward leaning at the time of a collision is suppressed, the fear of a passenger holding a fall is reduced.

7 and 8 show another example of the front wheel support mechanism for a wheelchair of the present invention, FIG. 7 is a partial vertical sectional side view, and FIG. 8 is a partial vertical sectional front view. The difference between this example and the support mechanism of the above configuration is that the front wheel 1 is cantilevered by the support member 41, and that the piston mechanism 44 is used in the swing mechanism 4 instead of the spring 42. is there. In this example, the same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding parts. The piston mechanism 44 has a horizontal shaft 4
Cylinder 4 rotatably coupled to the plane rotation unit 3 by 41
42, a piston 444 rotationally coupled to the support member 41 by a horizontal shaft 443, and a rubber member 445. The piston 444 is fitted in the cylinder 442 via the rubber member 445. In this example, when the support member 41 swings upward about the horizontal axis 43, the piston 444 resists the force of the rubber member 445 and the arrow D
Move in the direction.

Instead of the piston mechanism 44, a known coil spring, hydraulic damper unit or the like may be used.

[0021]

According to the first aspect of the present invention, when the front wheel collides with an obstacle on the road surface or climbs over unevenness, the crankshaft structure rotates rearward about the horizontal support shaft. The impact received from obstacles can be escaped backward. Therefore, it is possible to reduce the impact and vibration that the occupant receives from the unevenness and obstacles on the road surface, and improve the ride comfort of the occupant.

When the front wheels move down the step, the crankshaft structure rotates around the horizontal support shaft at the moment when the front wheels pass the step, and the axle is positioned vertically below the horizontal support shaft. When the front wheels land on the road surface, the crankshaft structure rotates around the horizontal support shaft, and the axle is positioned vertically above the horizontal support shaft, so the impact on the occupant during landing can be mitigated. . Therefore, from this point as well,
The ride comfort of passengers can be improved.

According to the second aspect of the present invention, the control means promotes the rearward rotation of the crankshaft structure about the horizontal support shaft, and the rotated crankshaft structure tries to return to its original position. Since the above is suppressed, the operation of the crankshaft structure can be favorably performed, and the effect according to claim 1 can be favorably exhibited. Therefore, the riding comfort of the passenger can be improved.

According to the third aspect of the present invention, when the front wheel collides with an obstacle on the road surface or goes over unevenness,
Since the support member swings upward against the elastic body, the impact can be released upward. In addition, at the time of a collision, the support member moves forward with respect to the front wheels in combination with the operation of the crankshaft structure, so that the amount of displacement in the traveling direction at the time of a collision can be lengthened, so that the instantaneous You can reduce the impact. Therefore, the impact on the occupant due to the obstacles and the unevenness can be further reduced, and the ride comfort of the occupant can be improved.

In addition, when the front wheels collide with obstacles on the road surface or pass over bumps and dips, the rearward rotation of the crankshaft structure and the rearward swing of the support member cause the support member to move. Since the vertical movements of the connected body frames are canceled out, it is possible to prevent the front side of the wheelchair from sinking and to suppress the forward lean. Therefore, the occupant's fear of falling can be reduced.

According to the fourth aspect of the invention, the traveling direction can be easily changed by the front wheels.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional side view of a wheelchair front wheel support mechanism of the present invention.

2 is a partial vertical sectional front view of the mechanism of FIG. 1. FIG.

FIG. 3 is a perspective view of a crankshaft structure.

FIG. 4 is a cross-sectional view showing the operating principle of the magnet gear.

5 is a side view showing the operation of the mechanism of FIG. 1 during a collision with an obstacle.

FIG. 6 is a side view showing the operation of the mechanism of FIG. 1 when descending a step.

FIG. 7 is a partial vertical cross-sectional side view of a front wheel support mechanism for a wheelchair according to another example of the present invention.

8 is a partial vertical cross-sectional front view of the mechanism of FIG.

FIG. 9 is a side view showing the operation of a conventional wheelchair front wheel support mechanism in the event of a collision with an obstacle.

[Explanation of symbols]

1 front wheel 5 Suspension mechanism 23 Vertical rotation axis 41 Support member 42 Spring (elastic body) 50 crankshaft structure 51 Horizontal support shaft 52 axles 53 arms 55 Magnet gear (control means)

Claims (4)

[Claims] 1. A support mechanism for supporting a front wheel of a wheelchair, comprising a suspension mechanism for rotatably supporting the front wheel at a lower end portion of a vehicle body frame, the suspension mechanism comprising a crankshaft structure, The shaft structure includes a horizontal support shaft rotatably supported at the lower end of the vehicle body frame, an axle that rotatably supports the front wheels, a horizontal support shaft, and a horizontal support shaft that is positioned at right angles to the axle. A front wheel support mechanism for a wheelchair, comprising an arm connecting one end to one end of an axle. 2. The suspension mechanism comprises control means for controlling the rotational operation of the horizontal support shaft, the control means being in a state in which the axle is vertically below the state in which the axle is vertically above the horizontal support shaft. The wheelchair front wheel support mechanism according to claim 1, wherein the front wheel support mechanism is controlled so as to make it easier to pick up. 3. A support member is connected to a lower end portion of a vehicle body frame, and the support member is vertically swingable,
The front wheel support mechanism for a wheelchair according to claim 1, wherein the upward swing is adapted to receive the resistance of the elastic body, and the horizontal support shaft is rotatably supported by the lower end portion of the support member. . 4. The front wheel support mechanism for a wheelchair according to claim 3, wherein the support member is rotatable about a vertical axis.