JP2012110620A - Caster structure for wheelchair, and wheelchair using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a caster structure for a wheelchair, the cater structure having impact resistance and durability by a simple mechanism and being entirely made of a non-metal material, and to provide a wheelchair entirely made of a non-metal material, which uses this caster structure.SOLUTION: The shaft of a caster part penetrates through the lower frame of the upper and lower frames of a wheelchair body and is disposed so as to be supported by the upper frame. The penetration part of the shaft and lower frame is supported by a lower bearing supporting the shaft such that the shaft is freely rotated, and by a lower bush fitted on the periphery of the lower bearing. The support part of the shaft and upper frame is supported by an upper bearing supporting the shaft such that the shaft is freely rotated, and by an upper-end bush fitted on the periphery of the upper bearing. The upper frame and lower frame are supported by an upper-end bush and a lower-end bush respectively at two points with a distance between them. Thus, three bushes of the upper-end bush, lower bush, and lower-end bush are provided.

Description

  The present invention relates to a wheelchair caster structure and a wheelchair using the same, and more particularly to a caster structure made of an all-nonmetallic material and an all-metal material wheelchair using the same.

  In recent years, passengers have been carefully inspected by metal detectors at airports to prevent hijacking and terrorism when using airplanes.

  In this passenger inspection, when a wheelchair user such as a disabled person or an elderly person who is forced to use a wheelchair is inspected, the metal used in the wheelchair reacts with the metal detector and is accurate. There is a problem that inspection cannot be performed.

  In such cases, caregivers such as airport guards are currently handling wheelchair users, taking into account the caregiver's labor and the psychological distress of wheelchair users. In some cases, the adoption of new means to solve these problems is urgent.

  As one means for solving such a situation, wheelchairs using all non-metallic materials that do not use any metallic materials have been developed.

  This wheelchair made of all non-metallic materials uses natural materials such as wood, bamboo, etc. for the frame, such as seats, backrests, armrests, etc. The parts that are difficult to be molded are made of fiber reinforced plastic or the like, and the bearings are manufactured using ceramic ball bearings or the like.

  This wheelchair made of all non-metallic materials is very useful in that it can be accurately inspected by metal detectors at airports without misdetection, and also uses a lot of natural materials. Thus, a warm and ergonomic wheelchair can be obtained.

  However, since there are limited conditions for adopting the constituent materials, there are still many problems to be investigated regarding the strength, durability, and shape of the material subjected to the impact.

  In particular, a caster serving as a front wheel, which is one of the important components in a wheelchair, is a part that requires impact resistance and durability because it directly receives vibration and impact from the ground.

  In order to ensure the safety of wheelchairs, a JIS driving durability test that repeats overriding movements of predetermined steps is prescribed, and according to this, durability by overriding 200,000 predetermined steps is required. Yes.

  Regarding wheelchair casters made of all non-metallic materials, when the JIS running durability test is performed using a generally known caster structure that has been changed to a non-metallic material as it is, cracks occur particularly quickly in the base of the caster shaft. Occurs and breaks.

  In fact, when caster shafts were manufactured from carbon fiber reinforced plastic (CFRP) and tested, they broke after stepping over only 400 steps, making it impossible to pass the JIS running durability test. Met.

  Heretofore, for a normal wheelchair, in order to absorb vibrations from the ground, a caster incorporating a buffer member has been proposed (see, for example, Patent Documents 1 and 2).

  Although these proposals are improved in terms of shock buffering, the structure is compact and complex, and these structures are all made of non-metallic materials and adopted for wheelchairs made of all non-metallic materials. It is very difficult.

  Even when these are employed, since the basic configuration of the caster itself is the same as that of the conventional caster, it is considered that a crack occurs in the root portion of the shaft of the caster in a short time.

Japanese Patent No. 2464718 Japanese Patent No. 4150583

  It is an object of the present invention to solve the above problems and to provide a caster structure for a wheelchair made of an all-non-metallic material having a shock resistance and durability by a simpler mechanism and a wheelchair made of an all-non-metallic material using the same. To do.

  The caster structure of the wheelchair of the present invention is characterized by the following.

  First, a wheelchair caster structure made of an all-non-metallic material, which is connected to a wheel, a tire attached to the outer periphery of the wheel, a yoke, a wheel shaft for rotatably attaching the wheel to the yoke, and the yoke Comprising a caster part in which a lower end bush is fitted to the connecting part of the yoke and the shaft, and the shaft of the caster part penetrates the lower frame with respect to the upper frame and the lower frame of the wheelchair body, It is arranged to be supported by the upper frame, and the penetrating part of the shaft and the lower frame is supported by a lower bearing that rotatably supports the shaft and a lower bush fitted to the outer periphery of the lower bearing. The support part of the upper bearing that rotatably supports the shaft and the outer periphery of the upper bearing The upper frame is supported by the upper end bush, the upper frame is supported by the lower bush, and the lower frame is supported at two points by a distance, and the upper bush, the lower bush, and the lower end bush are provided. ing.

  Second, in the wheelchair caster structure using the all non-metallic material according to the first aspect of the invention, the distance between the connecting portion of the yoke and the shaft and the lower bush is set shorter than the distance between the lower bush and the upper bush. ing.

  Thirdly, in the caster structure of the wheelchair made of the all non-metallic material of the first or second invention, the joint between the yoke and the shaft is for the yoke to support the wheel shaft for rotatably mounting the wheel. The left and right arm portions and the left and right arm portions are integrally formed with a joint portion, a cylindrical through hole is formed in the joint portion, and the inner wall of the through hole has a certain thickness. The lower end bush is fitted, and the lower end portion of the shaft is inserted into the lower end bush, so that the yoke, the lower end bush and the shaft are integrally formed.

4th is the wheelchair by the all non-metallic material using the caster structure of the wheelchair by the all nonmetallic material of the said 1st-3rd invention.

  According to the present invention, the shaft of the caster part is supported at the two points of the upper frame and the lower frame, the distance between the yoke and the caster connecting part of the caster part and the two support parts is defined respectively, and the upper end By cushioning at the three locations of the bush, lower bush, and lower end bush, the force applied to the caster part is dispersed and absorbed, making it a wheelchair caster made of all non-metallic materials with excellent impact resistance and durability. It becomes possible.

  In addition, a wheelchair made of all non-metallic materials incorporating this caster can be a wheelchair that can withstand a JIS running durability test and does not react to a metal detector at an airport or the like.

Schematic of caster part according to the present invention Schematic sectional view of a caster part according to the present invention Schematic of the frame part according to the present invention Schematic sectional view of a support according to the present invention Schematic sectional view of the wheelchair caster structure of the present invention

  Hereinafter, embodiments of a caster structure for a wheelchair according to the present invention will be described in detail.

  The drawings related to the frame portion for explaining the present invention all show the right frame for easy understanding of the description, but in actuality, it is composed of one set with the left frame and is symmetrical. Designed to.

  The configuration of the wheelchair made of all non-metallic material using the caster structure of the wheelchair of the present invention is the same as that of a generally known wheelchair except that all the constituent members are non-metallic materials. It is composed of a seat surface and a backrest provided on the main body, a main wheel attached to the frame, a caster attached to the frame, and a foldable footrest, each of which is made of resin bolts and nuts, etc. It is attached by.

  And the caster structure of the wheelchair of this invention is comprised from the support part for a caster part, a frame part, and a frame part to support a caster part.

  As shown in FIG. 1, the caster portion includes a wheel 12, a tire 13 attached to the outer periphery of the wheel 12, a yoke 11, a wheel shaft 14 for rotatably attaching the wheel 12 to the yoke 11, and a yoke. 11 comprises a shaft 10 connected to 11.

  The shaft 10 is formed with a lower flange 101 and an upper flange 102 for fitting and supporting a bearing of a support portion described later.

  The lower flange 101 may be formed integrally when the shaft 10 is formed, or a cylindrical member having a certain thickness may be inserted into the shaft 10 and bonded together.

The yoke 11 is integrally formed with a left and right arm portion for supporting a wheel shaft 14 for rotatably mounting the wheel 12 and a coupling portion for coupling the left and right arm portions, and the coupling portion and the arm portion are side surfaces. As seen from the top, it is bent in a U-shape.

  As shown in FIG. 2, a through hole is formed in the coupling portion of the yoke 11 in the vertical direction in which the shaft 10 is axially attached. A cylindrical lower end having a certain thickness is formed on the inner wall of the through hole. A bush 42 is fitted.

  The lower end of the shaft 10 is inserted into the cylindrical lower end bush 42, and the yoke 11, the lower end bush 42, and the shaft 10 are fitted together, and each of them is bonded and fixed with an adhesive so as not to rotate and fall off. It is configured.

  All the components of the caster part can be used without any limitation as long as they are all non-metallic materials. For example, the material of the yoke, wheel, wheel shaft is plastic, fiber reinforced plastic (hereinafter abbreviated as FRP), etc. It can be used as appropriate.

  Further, as the material of the lower end bush 42 fitted to the joint portion between the yoke 11 and the shaft 10, hard urethane or the like is preferably used.

  The tire 13 can be made of rubber, but the tire is in direct contact with the ground and is subject to vibrations and shocks. Therefore, the rubber material, hardness, etc. are appropriately selected according to the use situation of the wheelchair. Can be used. Moreover, the structure of the tire 13 can be appropriately selected from a hollow structure and a structure using wires other than metal.

  Furthermore, since the shaft 10 is particularly required to have strength and durability, the shaft 10 is preferably as large as possible, and may be round or hollow as long as the strength can be secured. The material is preferably FRP, and in particular, carbon fiber reinforced plastic (CFRP) can be suitably used.

  As shown in FIG. 3, the frame portion includes an upper frame 21 that is provided on both sides of the wheelchair body and supports the seat plate 20, and a lower frame 22 that is opposed to the lower portion of the upper frame 21.

  The upper frame 21 is laid horizontally from both sides so as to support the seat plate 20, and the upper frame 21 is attached and fixed to the seat plate 20. One end of the lower frame 22 is connected to the side surface of the seat plate 20, extends obliquely downward from the vicinity of the upper frame 21, curves at the lower end, and extends rearward.

  A concave recess 210 is formed on the lower back side of the upper frame 21 to support the upper end portion of the shaft of the caster portion. Further, the lower frame 22 is formed with a through hole 220 for passing the shaft of the caster part.

  If the material of a frame part is a nonmetallic material, it can be especially used without a restriction | limiting. Examples of these include plastic, FRP, wood, bamboo, and the like, but wood and bamboo are particularly preferred from the viewpoint of workability.

  The caster part is arranged so that the shaft of the caster part passes through the through hole of the lower frame and the upper end part of the shaft is supported by the upper frame 21. The caster portion is supported on the frame portions of the upper frame 21 and the lower frame 22 by a support portion including a bearing and a bush.

As shown in FIG. 4, the support portion includes an upper bearing 31 fitted to the shaft 10, an upper end bush 41, and a lower bearing 30 and a lower bush 40 fitted to the shaft 10.

  The shaft upper end portion of the shaft 10 has a diameter that is slightly narrower than the upper flange 102, and the upper bearing 31 that rotatably supports the shaft 10 is fitted to the upper flange 102.

  On the outer periphery of the upper bearing 31, a convex upper end bush 41 that fits on the outer periphery of the upper bearing 31 and that fits into a concave recess 210 formed in the upper frame 21 is attached. A space 411 is provided above the fitting portion between the upper bearing 31 and the upper end bush 41 so that the inner wall of the upper end bush 41 and the upper end portion of the shaft 10 do not come into contact with each other. Thereby, rotation of shaft 10 can be made smooth.

  Further, the shaft 10 has a diameter slightly larger than that of the shaft 10 on the yoke side with the lower flange 101 as a boundary, and a lower bearing 30 that rotatably supports the shaft 10 is fitted to the lower flange 101.

  A convex lower bush 40 that fits to the outer periphery of the lower bearing 30 and that fits to the inner wall of the through hole formed in the lower frame 22 is attached to the outer periphery of the lower bearing 30.

  A through hole having a diameter slightly larger than the shaft diameter is provided in the upper portion of the fitting portion of the lower bearing 30 of the lower bush 40 to allow the shaft 10 to pass therethrough so that the inner wall of the lower bush 40 and the shaft 10 do not come into contact with each other. Thus, the shaft 10 can be smoothly rotated.

  And as shown in FIG. 5, said support part is supporting the caster part and the frame part via the bearing and the bush.

  Here, the distance between the connecting portion of the yoke 11 and the shaft 10 and the lower bush 40 and the distance between the lower bush 40 and the upper end bush 41 are necessary and sufficient, and the shaft bends due to the impact depending on the length. It is important to endure while. With this configuration, the caster of the present invention can achieve impact resistance and durability.

  The upper bearing 31 and the lower bearing 30 are not particularly limited as long as they are made of a non-metallic material, but have strength and durability because they are members that directly support the weight of the wheelchair. As such, a ceramic ball bearing is preferably used.

  Since the upper bushing 41 that supports the upper bearing 31 and the upper frame 21 and the lower bushing 40 that supports the lower bearing 30 and the lower frame 22 are members that directly support the weight of the wheelchair, they can be easily deformed. A material having moderate elasticity is preferable.

  As such a thing, hard urethane rubber can be used conveniently. The hardness of the hard urethane rubber is not particularly limited. However, when the damper effect and the straight running stability of the wheelchair are taken into consideration, those having a hardness of 90 can be used particularly suitably.

According to the wheelchair caster structure of the present invention configured as described above, the shaft 10 of the caster part is respectively connected to the upper frame 21 and the lower frame 22 by the upper bearing 31 and the upper end bush 41 and the lower bearing 30 and the lower bush 40. Since it is supported, the entire caster portion is rotatable in the axial direction of the shaft 10.

  In addition, since the caster part is supported at a distance between two points of the upper frame 21 and the lower frame 22, the support part of the upper frame 21 is the working point and the support part of the lower frame 22 is the fulcrum. When the joint portion between the yoke 11 and the shaft 10 that has been damaged most in the experiments so far is viewed as a power point, the lower portion than the distance between the upper frame 21 (action point) and the lower frame 22 (fulcrum) as described above. In particular, when the distance between the frame 22 (fulcrum) and the joint (power point) between the yoke 11 and the shaft 10 is set short, a large force applied to the joint (power point) between the yoke 11 and the shaft 10 is lower frame 22. (Fulcrum) and the upper frame 21 (action point) are dispersed as a small force compared to when the distance is set longer.

  Furthermore, the lateral or vertical force applied to each point is further increased by the bushes provided at the lower frame 22 (fulcrum), the upper frame 21 (operation point), and the joint (power point) between the yoke 11 and the shaft 10. Absorbed.

  According to the present invention as described above, the force dispersing action by the configuration in which the caster portion is supported at two points of the upper frame 21 and the lower frame 22 and the configuration in which the upper end bush 41, the lower bush 40 and the lower end bush 42 are provided. In addition, due to the force absorbing action, casters made of all non-metallic materials that have been difficult in terms of strength can be used for wheelchairs.

  When a JIS running durability test was performed on a wheelchair using a caster structure made of all non-metallic materials with the above configuration, it withstood 310,000 times of impact, far exceeding the JIS standard of 200,000 times. Durability has been demonstrated.

  Thus, although excellent impact resistance and durability are realized by the above configuration, the wheelchair caster structure of the present invention and the wheelchair using a non-metallic material using the same are not limited to this configuration, Each part can be improved without departing from the basic configuration of the present invention.

  For example, the flange provided in the fitting part of the upper bearing 31 and the lower bearing 30 can be omitted when the bearing can be fitted by a bearing fixing member or the like.

  Further, in the frame portion, the upper end bush can be supported by the seat plate with the seat plate itself as the upper frame.

  Furthermore, the lower frame may be another constituent frame different from the lower frame having the above-described configuration, for example, a frame (not shown) provided on the inner side and both sides of the lower frame on the front and rear sides.

DESCRIPTION OF SYMBOLS 10 Shaft 101 Lower flange 102 Upper flange 11 Yoke 12 Wheel 13 Tire 14 Wheel shaft 20 Seat plate 21 Upper frame 210 Concave depression 22 Lower frame 220 Through hole 30 Lower bearing 31 Upper bearing 40 Lower bush 41 Upper end bush 411 Space 42 Lower end bush

Claims (4)

It consists of a wheel, a tire attached to the outer periphery of the wheel, a yoke, a wheel shaft for rotatably mounting the wheel to the yoke, and a shaft connected to the yoke. It has caster parts that are combined,
The shaft of the caster part is arranged to pass through the lower frame and supported by the upper frame with respect to the upper frame and lower frame of the wheelchair body, and the through part of the shaft and lower frame supports the shaft rotatably The lower bearing and the lower bush fitted to the outer periphery of the lower bearing are supported. The shaft and the upper frame support part are the upper bearing that rotatably supports the shaft and the upper end fitted to the outer periphery of the upper bearing. Supported by the bush,
All non-metal, characterized in that the upper frame is supported by the upper end bush and the lower frame is supported by the lower bush at two points at a distance, and three bushes are provided: the upper end bush, the lower end bush and the lower end bush Wheelchair caster structure with material.   The wheelchair made of an all-non-metallic material according to claim 1, wherein the distance between the connecting portion between the yoke and the shaft and the lower bush is set shorter than the distance between the lower bush and the upper end bush. Caster structure.   The connecting portion between the yoke and the shaft is formed by integrally forming a left and right arm portion for supporting the wheel shaft for rotatably mounting the wheel and a connecting portion for connecting the left and right arm portions. A through hole is formed in the inner wall of the through hole, and a cylindrical lower end bush having a certain thickness is fitted into the lower end bush. A lower end portion of the shaft is inserted into the lower end bush, and the yoke, the lower end bush and the shaft are The caster structure for a wheelchair made of an all-non-metallic material according to claim 1 or 2, wherein the caster structure is integrally formed.   A wheelchair made of all nonmetallic material using the caster structure of the wheelchair made of all nonmetallic material according to claim 1.

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