JPH0632108U - caster - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a caster which can smoothly climb over a step on a road surface and can be constructed in a small size. [Structure] Fork 1 that can swing around a vertical axis
0, and a wheel 20 rotatably provided, the wheel 20 being supported by the fork 10 so as to be swingable by a swing center axis parallel to the rotation center axis of the wheel 20. The hub 21, the tire 40 attached to the outer periphery of the rim and rotatably provided on the outer periphery of the wheel hub 21 via the bearing 43, and the wheel hub 21 installed between the wheel hub 21 and the fork 10. And a return spring 45 which urges the return spring 45 substantially downward.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a caster used for a wheelchair, etc., and more particularly to a caster that can easily climb over a step on a road surface.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, casters having wheels that pivot around a fork with a fork centering on a mounting portion to a vehicle body have been used for front wheels of wheelchairs and the like. When casters, this caster often receives an impact due to a step on the road surface or floor, and in order to mitigate the impact, a vertical axis for swinging and swinging is applied from a spring that has a vertical elastic force. Measures such as equipping a shock absorbing mechanism were taken.

However, a wheel of a caster provided with such a cushioning mechanism generally has a small vertical reaction, and there is a problem that it is difficult to get over depending on a step. Therefore, there is known a shock absorber in which a lower end of a fork supporting a wheel is pivotally supported such that its lower end can be displaced obliquely rearward and upward, and a spring for urging the lower end of the fork is urged substantially downward.

[0004]

[Problems to be solved by the device]

 However, in such a conventional shock absorber for casters, the wheels move diagonally rearward and upward when climbing over a step to easily climb over a step, but a spring or a spring supporting arm projects around the caster to increase the size. Therefore, for example, when mounting on a wheelchair, there is a problem that it interferes with other members of the wheelchair, making it difficult to assemble, and hindering getting on and off the wheelchair.

The present invention has been made to solve the above problems, and an object thereof is to provide a caster capable of smoothly overcoming a step on a road surface and having a small size. To do.

[0006]

[Means for Solving the Problems]

 The present invention has been made to achieve the above object, and is a caster including a fork capable of swinging about a vertical axis and a wheel rotatably provided, wherein the wheel is A wheel hub swingably supported by the fork by a swing center axis parallel to the center axis of rotation of the wheel, and a wheel hub mounted on the outer circumference of the rim and rotatably provided on the outer circumference of the wheel hub via a bearing. And a return spring interposed between the wheel hub and the fork to urge the wheel hub substantially downward.

[0007]

[Action]

 The present invention is configured as described above, and the wheels of the caster are supported so that the tire rotates about the center point of the wheel hub and the wheel hub can swing about the swing center axis. It is always biased by the return spring and located near the bottom of the fork.

When a traveling wheel comes into contact with a step on the road surface, the tire receives resistance due to the step, and a rearward pushing force and a upward lifting force act on the wheel hub. These forces overcome the biasing force of the return spring and cause the wheel hub to swing and displace diagonally rearward and upward around the swing center axis. As a result, the wheel reaches the step without transmitting its displacement to the fork.

When the wheel passes through the step, the wheel hub is pulled by the urging force of the return spring to restore the wheel to the lower position of the fork.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a caster of this embodiment, FIG. 2 is a sectional view taken along the line AA, and FIG. 3 is a partially exploded perspective view.

A caster indicated by reference numeral 1 in the drawing includes a fork 10 and a wheel 20, and the wheel 20 is rotatably attached to a wheel hub 21 which is swingably supported by the fork 10 and an outer circumference of the wheel hub 21. The tire 40 is provided, and the return spring 45 is interposed between the wheel hub 21 and the fork 10.

The fork 10 is formed with a pair of support portions 12 extending downward from both sides of the mounting base portion 11. The pair of support portions 12 have holes 13, 13 and a hole 15 facing each other in the horizontal direction. , 15 are provided.

The wheel hub 21 of the wheel 20 is composed of a pair of left and right symmetrical disk-shaped members 21R and 21L having an annular protrusion 22 on one side on the working side, and the annular protrusions 22 and 22 are opposed to each other. It is formed integrally.

The disc-shaped member 21R is provided with a shaft hole 23 having an axis parallel to the disc center axis at a predetermined position eccentric from the disc center, and the shaft hole 23 has a collar 32 of a predetermined length. Is inserted and fixed. A guide hole 25, which is an arc-shaped elongated hole centered on the shaft hole 23, is formed. Further, the right half of the bearing mounting groove 27 is formed on the outer peripheral side of the annular projection 22. Has been done.

The disc-shaped member 21L is formed symmetrically with the disc-shaped member 21R except that the collar 32 is not fixed to the shaft hole 23. When the shaft hole 23 of the disk-shaped member 21L is externally fitted to the color 32 of the disk-shaped member 21R and the two members 21R and 21L are tightened and integrated by the bolt 28 and the nut 29, left and right guide holes are formed. 25 and 25 face each other, and an annular bearing mounting groove 27 is formed on the outer periphery of the wheel hub 21.

The wheel hub 21 has a bolt 32, which serves as a swing center axis, passed through a collar 32 of the wheel hub 21, and is swingable in the holes 13 and 13 of the fork 11 by a nut 34 and a washer (not shown). Installed on. Further, a collar 35 having a diameter smaller than the width of the guide hole 25 is inserted into the guide holes 25, 25, and the collar 35 is fixed to the holes 15, 15 of the fork 11 by a bolt 36, a nut 37 and a washer penetrating the collar 35. Has been done. The collar 35 regulates the moving range of the guide holes 25, 25, that is, the maximum displacement of the wheel hub 21 swinging.

The tire 40 is made of a rubber-like elastic member and is integrally formed on the outer periphery of the rim 41. A bearing 43 is fitted in the inner periphery of the rim 41 of the tire 40, and the bare ring 43 is fitted in the bearing mounting groove 27 and mounted on the wheel hub 21. As a result, the tire 40 is formed so as to rotate with the center of the disk of the wheel hub 21 as the center of rotation.

The return spring 45 is composed of a tension coil spring, is interposed between the collar 35 and a predetermined bolt 28, and urges the wheel hub 21 to pull it substantially downward.

In the caster 1 thus configured, the vertical shaft 18 is attached to the attachment base 11 of the fork 10, and the caster 1 is attached so as to be swingable about the vertical shaft 18, for example, as a front wheel of a wheelchair.

When the user rides on the wheelchair, the weight of the wheelchair is balanced with the urging force of the return spring 45 so that the wheel 20 is located below the fork 10, that is, the upper end of the guide hole 25. When the wheelchair travels on the road surface GL in FIG. 4 in the arrow direction, the tire 40 of the wheel 20 rotates the center point of the wheel hub 21. The tire 40 rotates about the central axis and gently undulates the road surface GL. The tire 40 swings around the swing central axis of the wheel hub 21 to absorb the vertical displacement of the wheel 20 due to the unevenness.

When the wheel 20 reaches the step S, the tire 40 is subjected to the rearward pushing force and the upward lifting force of the step S. Due to these acting forces, the tire 40 is swung and displaced obliquely rearward and upward, overcoming the spring force of the return spring 45.

Due to the displacement of the tire 40, the wheel 20 reaches the step S without absorbing the impact of the step S and transmitting the displacement to the fork 10 (see FIG. 4). Then, the return spring 45 restores the tire 40 to the lower position of the fork 10 (see FIG. 1) by the urging force.

When the wheel 20 reaches the downward step S ′, the urging force of the return spring 45 causes the tire 40 to quickly swing to reach the road surface GL, which alleviates the vertical movement of the wheelchair. When the wheel 20 reaches the road surface GL, the wheel 20 returns to the lower position of the fork 10 shown in FIG.

The present invention is not limited to the above description and the illustrated examples, and its embodiment can be changed without departing from the technical idea of the present invention. For example, the wheel hub may be composed of one member.

Further, the return spring may be any one as long as it biases the wheel hub downward, and the shape and mounting method thereof are not particularly limited, such as a compression coil spring and a torsion coil spring.

[0027]

[Effect of device]

 As described above, according to the caster of the present invention, the wheel swings up and down with respect to the fork, so that the wheel can quickly follow the step on the road surface and smoothly pass over the step. You can

Further, since the swing arm portion for swinging the wheels is composed of the wheel hub itself and the return spring is provided in the wheel hub, the device can be made extremely small. You can As a result, it is possible to easily attach the device to a wheelchair and the like, and it is possible to eliminate obstacles when getting on and off the wheelchair.

[Brief description of drawings]

FIG. 1 is a side view of a caster according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a partially exploded perspective view of a caster.

FIG. 4 is a side view showing a state when climbing over a step.

[Explanation of symbols]

 1 Caster 10 Fork 20 Wheel 21 Wheel Hub 25 Guide Hole 33 Bolt (Rotating Center Axis) 35 Collar 40 Tire 43 Bearing 45 Return Spring

Claims (1)

[Scope of utility model registration request] 1. A caster comprising a fork capable of swinging about a vertical axis and a wheel rotatably provided, wherein the wheel is a swing center parallel to the center axis of rotation of the wheel. A wheel hub swingably supported by the fork by a shaft, a tire mounted on the outer circumference of the rim and rotatably provided on the outer circumference of the wheel hub via a bearing, and between the wheel hub and the fork A caster, which is interposed between the wheel hub and the wheel hub to urge the wheel hub substantially downward, and a caster.