JPH1191304A - Caster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly run by low labor even on a step. SOLUTION: In this caster, a main shaft 4 is placed at the rear lower end of a bearing part 1, and a main wheel 5 is rotatably provided around it. While, an auxiliary shaft 6 is provided at the front lower end of the bearing part 1, and an auxiliary wheel 7 is rotatably provided around it. The auxiliary wheel 7 arranged away from a floor surface 9 on which the main wheel 5 runs. The main wheel 5 and the auxiliary wheel 7 are interconnected through a belt made of elastic material such as rubber on their outer peripheries.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster which makes it easy to get over obstacles such as steps present on a traveling path.

[0002]

2. Description of the Related Art Conventionally, casters have been often used in, for example, wheelchairs, trolleys, and tables so that a user can move them easily and smoothly. That is, for example, it is used as a front wheel in a wheelchair, on a lower surface of a luggage carrier in a bogie, and on a lower portion of a leg in a table, and fulfills the above-mentioned purpose. Among them, an example of using a conventional caster in a wheelchair will be described.

FIG. 5 is a side view showing the form of a general wheelchair. In the figure, when a user sits on a seat portion 23 of a wheelchair 20 and travels on the floor 9 by manually rotating rear wheels 21 provided on the right and left rear portions, or a caregiver travels with a handle 24. In some cases, wheelchair 20 as front wheel
Since the casters 22 provided on the lower left and right sides of the front part rotate accordingly, the movement of the wheelchair 20 can be performed easily and smoothly.

FIG. 6 is a side view showing this caster 22 in detail. As shown in the figure, a turning shaft 2 extends upward from the upper surface of the bearing portion 1 ', and a screw portion 3 for fitting a retaining nut to the wheelchair 20 main body side is provided at the tip thereof. I have. A rotating shaft 4 'is attached to a lower portion of the bearing portion, and wheels 5' are rotatably provided around the rotating shaft 4 '. At this time, the turning shaft 2 and the rotating shaft 4 'do not cross each other even on an extension thereof, and are separated by a predetermined distance.

Now, when the caster 22 travels in the direction indicated by the arrow a in accordance with the travel of the wheelchair 20, the turning shaft 2 and the rotating shaft 4 'are separated by a predetermined distance as described above.
Due to the frictional force between the wheels 5 ′ and the floor 9, the bearing 1 ′ turns around the turning shaft 2 as shown by the arrow b, and the rotating shaft 4 ′ turns around in the direction opposite to the running direction shown by the arrow a, The wheel 5 'always rotates along the traveling direction as shown by the arrow c.
As described above, casters capable of performing efficient rotation with little friction have been practically used.

Depending on the use condition of the casters, it is not always necessary to turn the bearing. For example, a rear wheel of a bogie does not have a turning shaft and the bearing is directly attached to the main body and fixed. Casters are used.

[0007]

However, in the above-described configuration, even if there is a small step such as a threshold on the running floor, a great deal of labor is required to overcome it. For example, as shown in FIG.
When trying to overcome it, unless the outer diameter of the wheel 5 'is considerably large, the contact angle θ between the corner of the threshold 11 and the wheel 5' becomes large, making it extremely difficult to climb. turn into. In particular, in the case of a wheelchair, if the occupant tries to get over a step by himself, it is not possible to lift the wheelchair by himself,
In some cases, traveling is almost impossible even with a step of only 2-3 cm.

An object of the present invention is to solve the above problems and to provide a caster capable of running smoothly with little labor even if there is a step.

[0009]

In order to achieve the above object, according to the present invention, there is provided a bearing, a main wheel rotatable around a main shaft provided on the bearing, and a main wheel mounted on the bearing. An auxiliary wheel rotatable around an auxiliary shaft provided at a distant position, the auxiliary wheel being at a position away from a floor surface on which the main wheel runs, and connecting the main wheel and the auxiliary wheel to each other. The outer circumference is connected by a belt.

[0010] Further, an adjuster for adjusting the tension of the belt is provided. Further, the bearing portion has a turning shaft, and the bearing portion turns around the turning shaft so that the main wheel follows the traveling direction of the caster.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a basic configuration of an embodiment of the present invention. In the figure, reference numeral 1 denotes a bearing, and a main shaft 4 is provided at a lower end of a rear portion thereof. A main wheel 5 is rotatably provided around the main shaft. An auxiliary shaft 6 is provided at the lower end of the front part of the bearing 1.
Are provided, and an auxiliary wheel 7 is rotatably provided therearound. The auxiliary wheels 7 are arranged at positions away from the floor 9 on which the main wheels 5 run. The main wheel 5 and the auxiliary wheel 7 are connected at their outer circumferences by a belt 8 made of an elastic body such as rubber.

Further, a turning shaft 2 extends upward from an upper surface of the bearing portion 1, and a screw portion 3 for fitting a retaining nut with respect to the main body side is provided at a tip end thereof. At this time, the turning shaft 2 and the main shaft 4 do not cross each other even on an extension thereof, and are separated by a predetermined distance. The shape of the revolving shaft 2 is not necessarily limited to the shape shown in the figure, but various shapes may be used depending on the state of attachment to the main body and the type of the bearing.

Now, when the caster of the present invention travels in the direction indicated by arrow A in response to traveling of the body such as a wheelchair, the turning shaft 2 and the main shaft 4 are separated by a predetermined distance as described above. The frictional force between the wheel 5 and the floor 9 causes the bearing 1
Turns around the turning shaft 2 as shown by the arrow B, the main shaft 4 turns around in the direction opposite to the running direction indicated by the arrow A, and the main wheels 5 always rotate along the running direction as shown by the arrow C. Become.
In addition, as described in the above-mentioned conventional technology, the bearing portion does not necessarily need to be turned depending on the use state of the caster. For example, the rear wheel of the bogie has no turning shaft, and the bearing portion is directly connected to the main body side. A caster that is attached and fixed to the vehicle is used.

When the main wheel 5 rotates as indicated by the arrow C, the rotation is transmitted to the auxiliary wheel 7 by the belt 8, and the auxiliary wheel 7 rotates in the same direction as the main wheel 5 as indicated by the arrow D.
At this time, as shown in the figure, since the straight portion under the belt 8 forms an angle α with the floor surface 9, this is set to be sufficiently smaller than the angle θ shown in the above-mentioned conventional technology. In this case, even if the threshold 11 is on the floor 9 shown in the figure,
You can get over it easily.

Further, even if there is a high step, such as a sill 12 shown by a dashed line in FIG. Can be. The smaller the angle α, the less effort is required to get over the steps,
In this case, unless the distance between the main wheel 5 and the auxiliary wheel 7 is increased, the height of the step that can be climbed over is limited. Therefore, the optimal setting is performed in consideration of the positional relationship between them.

FIG. 2 is a view showing an example in which the main wheel 5 and the auxiliary wheel 7 are viewed from the front. FIG. 2A shows a case where the cross section of the belt 8 is round, and FIG. Is a V-shaped cross section. As shown in these figures, the main wheel 5 and the auxiliary wheel 7 are provided with grooves for hanging a belt 8 (indicated by a dashed line) on the outer periphery thereof, and have a so-called pulley shape. In the case of FIG. 7A, the belt 8 has a round cross section.
(B)
In the case of (1), the groove is also V-shaped to hang the belt 8 having a V-shaped cross section. The cross section of the belt 8 and the shape of the groove of each wheel are not limited to this example, and various variations can be considered.

As a material of the belt 8, an elastic body such as rubber is used to provide cushioning. Also,
In order to reduce expansion and contraction and improve durability, steel or the like may be inserted as a core body. Further, when the cross section of the belt 8 has a V-shape, the outer periphery may be bulged as shown in FIG. 3 in order to improve cushioning. The bearing portion 1 has a U-shape when viewed from the front as shown by a two-dot chain line in FIG. 2, and generally receives the axle on both sides, straddling the left and right sides of each wheel. Of course, this form is not limited, and the axle may be cantilevered, in which case the belt 8 can be easily replaced.

FIG. 4 is a view showing an example in which a mechanism for adjusting the belt tension is provided on the caster of the present invention. As shown in FIG. 1, an adjuster 10 extends downward from an upper portion of the bearing 1, and the adjuster 10
The tension of the belt 8 is added and adjusted by pressing against the outer periphery of the belt 8 to adjust its length. A roller is provided at the tip of the adjuster 10 so that an unnecessary frictional force is not easily applied to the belt 8. However, the present invention is not limited to this configuration. The adjuster 10 may be pressed against the inner periphery of the belt 8, or the mounting hole of the auxiliary shaft 6 on the bearing unit 1 may be elongated, and the main wheel 5 and the auxiliary wheel The tension of the belt 8 may be adjusted by adjusting the distance from the belt 7.

When the caster according to the present invention is used, a particularly large tension is applied to the outer periphery of the portion of the belt 8 which is wound around the wheel, so that the belt 8 is prevented from being torn at that portion. As shown in FIG. 8, a notch as shown by an arrow may be added to the outer periphery of the belt 8 in advance.

[0020]

As described above, according to the present invention,
It is possible to provide a caster that can run smoothly with little effort even if there is a step. If the casters are designed to be compatible with the existing casters, the casters of the present invention need only be replaced with the existing main body, so that the casters of the present invention can be easily used and spread.

According to the second aspect, the belt can be used with the tension of the belt always being in an optimum state, so that a stable performance as a caster can be exhibited. Further, according to the third aspect, since the main wheel always rotates along the traveling direction, it is possible to perform efficient rotation with little friction.

[Brief description of the drawings]

FIG. 1 is a side view showing a basic configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an example in which a main wheel and an auxiliary wheel are viewed from the front.

FIG. 3 is a diagram showing an example in which a bulge is provided on the outer periphery of a V-belt.

FIG. 4 is a diagram showing an example in which a mechanism for adjusting the tension of the belt is provided.

FIG. 5 is a side view showing a form of a general wheelchair.

FIG. 6 is a side view showing an example of a conventional caster in detail.

FIG. 7 is a diagram showing a relationship between a conventional caster and a threshold.

FIG. 8 is a diagram illustrating a state in which a notch is added to the outer periphery of the belt.

[Description of Signs] 1 Bearing part 2 Revolving shaft 3 Screw part 4 Main shaft 5 Main wheel 6 Auxiliary shaft 7 Auxiliary wheel 8 Belt 9 Floor surface 10 Adjuster

Claims (3)

[Claims] 1. A bearing portion, a main wheel provided on the bearing portion rotatable around a main shaft, and an auxiliary wheel rotatable about an auxiliary shaft provided on the bearing portion at a position away from the main shaft. A caster, wherein the auxiliary wheel is located at a position distant from a floor surface on which the main wheel travels, and the main wheel and the auxiliary wheel are connected to each other by a belt at the outer periphery thereof. 2. The caster according to claim 1, further comprising an adjuster for adjusting a tension of the belt. 3. The bearing according to claim 1, wherein the bearing has a turning shaft, and the bearing turns around the turning shaft so that the main wheel follows a traveling direction of a caster. Or the caster according to claim 2.