JPS63154401A - Caster - Google Patents

Abstract

PURPOSE:To slow down the rotating action of a caster and improve straight running property by forming recesses and projections engaged with each other on a coupling section between a bracket fixed to an object to be moved and a rotary yoke fitted to a shaft held by the bracket. CONSTITUTION:A caster 1 fitted to a front leg 2 of a handcart or the like is constituted of a fixed bracket 4 fixed to the front leg 3 via a pin 3, a shaft 5 extended and held by the fixed bracket 4, a rotary yoke 6 held rotatably around the shaft 5, and a wheel 8 rotatably directed by the rotary yoke 6 via a wheel 7 horizontally extended at a position horizontally displaced from the shaft 5. Recesses and projections A, B are formed on the upper end face of the rotary yoke 6 along a circle centering the shaft 5 penetrating the center opening. Similar recesses and projections C, D are formed on the downward face of the fixed bracket 4 brought into contact with the upper end face of the rotary yoke 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to casters that are attached to a moving object to facilitate changing direction of the object.

BACKGROUND OF THE INVENTION To facilitate changes in direction, casters are sometimes attached to pushcarts such as baby buggies, shopping cars, luggage carriers, or objects to be moved. For example, casters are attached to the lower ends of a pair of front legs of a baby carriage. The caster is rotatable around the rotation axis, and rotatably supports the front wheel via an axle extending horizontally at a position horizontally shifted from the rotation axis.

When the baby carriage is moved on a flat road while being pushed backwards, the axle of the front wheel is positioned behind the rotational axis of the casters with respect to the direction of travel. Then, when changing the direction of the baby carriage, the casters appropriately rotate, making it possible to change the direction easily. In this way, handcarts such as baby carriages have excellent operability by being provided with casters.

[Problems to be Solved by the Invention] However, if the casters are capable of freely pivoting, the casters react too sensitively to, for example, unevenness or slopes on the road. Therefore, even when a pushcart such as a baby carriage is operated to travel straight, the baby carriage may react sensitively to irregularities on the road, causing its travel trajectory to meander or proceed in an unintended direction. There is also. This is undesirable from a safety and operational standpoint.

Therefore, it is an object of the present invention to provide casters that do not react too sensitively to unevenness or slopes on the road and can maintain stable straight running conditions.

[Means for Solving the Problems] A caster according to the present invention includes: a fixed bracket fixed to an object moved by the caster; a shaft extending in the vertical direction and held by the fixed bracket;
a rotating yoke that is held by the shaft and is rotatable around the shaft with its upper end fitted into the lower end of the fixed bracket; and a rotating yoke that extends horizontally at a position horizontally offset from the shaft. and wheels rotatably supported by a rotating yoke via an axle. At the fitting portion between the fixed bracket and the rotating yoke, a circle centered on the shaft is formed on the downward and upward surfaces of the fixed bracket and the rotating yoke that surround the shaft and abut each other from above and below. It is characterized by having concavo-convex portions that can engage with each other along the concave and convex portions.

[Operations and Effects of the Invention] The fixed bracket and rotating yoke, which surround the shaft and abut each other from above and below, have uneven parts on the downward and -L facing surfaces that engage with each other along a circle centered on the shaft. is formed.

The state in which the recess and the projection are engaged is the most stable state. In order to release this engaged state, it is necessary to apply a rotational force greater than a predetermined value to the rotating yoke. If a small rotational force is applied, the rotating yoke will not rotate relative to the fixed bracket. The rotational force exerted on the rotating yoke by uneven surfaces or inclined surfaces on the road is relatively small. Therefore, the caster according to the present invention does not react very sensitively to irregularities and slopes on the road.

For example, assume that casters according to the present invention are attached to a handcart such as a baby carriage or a shopping car. In this case, the positional relationship between the uneven portions formed on the lower and upper surfaces of the fixed bracket and the rotary yoke is selected so that they engage with each other when the handcart is running straight. Since the engagement state of the uneven portions is the most stable, the handcart can be driven straight forward in a stable state. Moreover, this handcart does not react very sensitively to bumps and slopes on the road. On the other hand, when the handcart is operated to change direction, a rotational force of more than a predetermined value is applied to the rotating yoke.

Therefore, the engaged state of the concavo-convex portion is released, and the rotating yoke rotates relative to the fixed bracket. In this way, the direction of the wheelbarrow can be easily changed.

As described above, according to the present invention, casters with excellent safety and operability can be obtained.

[Embodiment] FIG. 1 shows an embodiment of the present invention. The illustrated casters 1 are attached to the front legs 2 of a handcart, such as a baby carriage, a shopping car, etc., in order to facilitate changing direction of the handcart. This caster 1 includes a fixed bracket 4 fixed to a front leg 2 via a pin 3, a shaft 5 extending vertically and held by a fixed bracket 4, and a shaft 5.
The rotating yoke 6 is connected to the rotating yoke 6 through an axle 7 extending horizontally at a position horizontally shifted from the shaft 5.
and wheels 8 which are rotatably supported by.

A cylindrical opening is formed at the lower end of the fixed bracket 4, and the upper end of the cylindrical rotating yoke 6 is fitted into this opening. A sleeve 9 is fixedly attached to the center hole of the rotating yoke 6 through which the shaft 5 is inserted. The shaft 5 extends through this sleeve 9.

FIG. 2 shows a plan view of the rotating yoke 6 shown in FIG. 1, and FIG. 3 shows a front view thereof. Further, FIG. 4 shows a developed cross-sectional view taken along the circle 2 in FIG. 2, thereby clarifying the shape of the upper end surface of the rotating yoke 6.

As is clear from these figures, an uneven portion is formed on the upper end surface of the rotating yoke 6 along a circle centered on the shaft 5 passing through the central opening.

In FIGS. 2 to 4, the portion indicated by A is a flat ridge, and the portion indicated by B is an arcuate recess.

FIG. 5 shows a front sectional view of the fixing bracket shown in FIG. As described above, the lower end of the fixed bracket 4 receives the upper end of the rotating yoke 6, but here we will focus on the downward facing surface that abuts the upper end surface of the rotating yoke 6.

An uneven portion is formed on this downward surface along a circle centered on the shaft 5 inserted through the center. The shape of the uneven portion formed on the downward surface of the fixed bracket 4 is similar to that of the rotating yoke 6.
It is adapted to correspond to the shape of the uneven portion formed on the upper end surface. In FIG. 5, the portion indicated by C is a trough in the form of a plane, and the portion indicated by D is an arcuate convex portion.

During normal running, that is, when the handcart is moving straight, the troughs C of the fixed bracket 4 and the peaks A of the rotating yoke 6 are in contact with each other, and the arcuate convex portion of the fixed bracket 4 is in contact with the crest A of the rotating yoke 6. It is in contact with the arcuate recess B.

As described above, in the present invention, at the fitting portion between the fixed bracket 4 and the rotating yoke 6, the fixed bracket 4 surrounds the shaft 5 and abuts each other from above and below.
The lower and upper surfaces of the rotating yoke 6 are formed with concave and convex portions that engage with each other along a circle centered on the shaft 5 .

The state in which the concavo-convex portions are engaged is the most stable state.

This stable state is maintained relatively firmly by the downward gravity applied from the fixed bracket 4 to the rotating yoke 6. Therefore, in order to release the engaged state of the uneven portions and rotate the rotating yoke 6 relative to the fixed bracket 4, it is necessary to apply a rotational force of a predetermined amount or more to the rotating yoke 6.

Therefore, the illustrated casters 1 do not react sensitively to unevenness or slopes on the road, and maintain a stable straight running state.

On the other hand, when the handcart is operated to change direction, a rotational force of more than a predetermined value is applied to the rotating yoke 6. Therefore, the rotary yoke 6 rotates, and the peak A of the rotary yoke 6 comes into contact with the arcuate recess B of the fixed bracket 4. In other words, as the rotating yoke 6 rotates, the rotating yoke 6 operates to slightly lift the fixed bracket 4 upward.

Note that the shaft 5 has a length that allows the fixed bracket 4 to move upward.

The uneven portions formed on the lower and upper surfaces of the fixed bracket 4 and the rotating yoke 6 must be selected to have a shape that does not impede rotation of the rotating yoke 6 with respect to the fixed bracket 4. The greater the difference in height between the concave and convex portions that engage with each other, the more stable the caster 1 can maintain a stable straight running state. However, on the other hand, the rotation of the rotary yoke 6 is inhibited to a greater degree (increasingly), making it difficult to change the direction. The difference in height between the parts is set to be 2 mm or less.If the difference in height is on this level, it will not cause much trouble to the rotation of the rotating yoke 6 and will not impair the original function of the caster.

As described above, the illustrated caster 1 has excellent safety and operability, but also has the following advantages. This will be explained with reference to FIG.

Now, let's focus on the fitting portion between the fixed bracket 4 and the rotating yoke 6. The upper end of the rotating yoke 6 is fitted into an opening formed at the lower end of the fixed bracket 4.
If the outer circumferential surface of the upper end of the rotary yoke 6 and the inner circumferential surface of the opening of the fixed bracket 4 are in too close contact, rotation of the rotary yoke 6 will be hindered. Therefore, a gap 10 is formed between the outer peripheral surface of the upper end of the rotating yoke 6 and the inner peripheral surface of the opening of the fixed bracket 4. This gap 1
0 can be quite large due to manufacturing tolerances. In the conventional caster, since this gap 10 exists, the rotating yoke 6 relatively slides horizontally within the opening of the fixed bracket 4. In other words, although the amount of movement is small, the conventional caster has a structure in which the upper end of the rotating yoke 6 moves randomly within the opening of the fixed bracket 4 in the horizontal direction. This relative side-slipping of the rotating yoke 6 manifests as rattling between the fixed bracket 4 and the rotating yoke 6, and during use, it manifests as horizontal vibration of the fixed bracket 4 or the rotating yoke 6. I was worried.

However, in the embodiment described above, at the fitting portion between the fixed bracket 4 and the rotating yoke 6, the fixed bracket 4 surrounds the shaft 5 and abuts each other from below -L.
The lower and upper surfaces of the rotating yoke 6 are formed with concave and convex portions that engage with each other along a circle centered on the shaft 5 .

Therefore, even if there is a gap 10 between the outer circumferential surface of the upper end of the rotating yoke 6 and the inner circumferential surface of the opening of the fixed bracket 4 that receives this upper end, the uneven parts engage with each other and the fixed bracket Relative horizontal skidding between the rotary yoke 4 and the rotary yoke 6 is prohibited, and rattling and vibration between the two are prevented.

FIG. 6 is a front sectional view showing another embodiment of the invention. The illustrated caster 20 includes a fixed bracket 23 fixed to a front leg 21 of a handcart such as a baby carriage or a shopping car via a pin 22, a shaft 27 extending vertically and held by the fixed bracket 23, and a shaft 27 held by the shaft 27. A rotating yoke 24 is rotatably provided around the shaft 27, and a wheel 26 is rotatably supported by the rotating yoke 24 via an axle 25 extending horizontally at a position horizontally shifted from the shaft 27. It is equipped with

Further, a slide member 28 that is movable up and down along the shaft 27 and a spring 29 that urges the slide member 28 to always move downward are housed in the fixed bracket 23 of the illustrated caster 20. ing. The slide member 28 is always in contact with the upper end of the rotating yoke 24 due to the biasing force of the spring 29.

A slide member 28 is illustrated in FIGS. 7-10. As shown in the figure, a rib 30 extending in the vertical direction is formed on the outer peripheral surface of the slide member 28. Correspondingly, as shown in FIG.
A guide groove 31 for receiving the rib 30 is formed on the inner circumferential surface of the guide groove 31 . In this way, the slide member 28 can move up and down without rotating relative to the fixed bracket 23.

Further, the slide member 28 has a downwardly protruding hanging wall 3.
It has 2. The hanging wall 32 has a flat portion E located at its tip and an inclined portion F connected to the flat portion E.

The rotating yoke 24 is illustrated in FIGS. 12-14. The rotating yoke 24 has, at its upper end portion, an upwardly projecting wall 33 that projects upward, and a trough 34 that is connected to the upwardly projecting wall 33 via an inclined surface. Tanibe 3
4 is the lowest upper end surface and has a flat shape. Further, the upper end surface of the upwardly protruding wall 33 is also formed into a flat shape.

Furthermore, as shown in the figure, the rotating yoke 24 has an axle 25
It has a cylindrical portion 35 that receives the cylindrical portion.

FIG. 15 shows the downward surface of the slide member 28 and the rotating yoke 2.
4 is a plan view schematically showing a portion in contact with the upper surface of FIG. Furthermore, FIG. 16 is a front sectional view corresponding to FIG. 15. When the wheelbarrow is running straight,
The state is shown in FIGS. 15 and 16.

In FIG. 15, the hanging wall 32 (
E, F) are marked with diagonal lines downward to the left, and the rotating yoke 24
The upwardly protruding wall 33 and the valley portion 34 are diagonally diagonally downward to the right.

When the handcart is running straight, as shown in FIGS. 15 and 16, the hanging wall 32 of the slide member 28
The flat portion E of is in contact with the valley N34 of the rotating yoke 24. The inclined portion F of the hanging wall 32 is in contact with the inclined surface of the rotating yoke 24. In other words, slide member 2
The flat portion E located lowest among the downward surfaces of the rotating yoke 24 is the valley portion 3 located lowest among the upward surfaces of the rotating yoke 24.
It is in contact with 4. Therefore, FIGS. 15 and 16
The state shown in the figure is the most stable state, and this stable state is maintained relatively firmly by the action of the spring 29 shown in FIG. In this way, when the handcart is being operated to run straight, the casters 20 do not react very sensitively to unevenness or slopes on the road, and stably maintain the straight running state.

On the other hand, when changing the direction of the handcart, the rotating yoke 24
A rotational force of a predetermined amount or more is applied to. As a result, the rotating yoke 24 rotates, and the sliding member 28 moves upwardly against the force of the spring 29 accordingly. That state is the first
7 and 18. As shown,
The lowest flat portion F of the downward surface of the slide member 28 is in contact with the inclined surface of the rotating yoke 24 .

Note that the rotation range of the rotating yoke 24 is the same as that of the sliding member 28.
The terminal end is defined by the hanging wall 32 of the rotary yoke 24 coming into contact with the upwardly protruding wall 33 of the rotary yoke 24.

Although two embodiments have been described using FIGS. 1 to 18, they are merely exemplary embodiments of the present invention. Therefore, various modifications and variations are possible within the scope of equivalents of this invention. For example, the shape of the uneven portions formed on the lower surface of the fixed bracket or the slide member and the upper surface of the rotating yoke can be changed as appropriate. In addition, in the illustrated embodiment, the upper end of the rotating yoke is received in the opening formed in the lower end of the fixed bracket. The lower end of the fixing bracket may be received within.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing an embodiment of the present invention. FIG. 2 is a plan view of the rotating yoke 6 shown in FIG. 1. FIG. 3 is a front view of the rotating yoke 6. FIG. 4 is an expanded view of a cross section taken along the circle 2 in FIG. 2. FIG. 5 is a front sectional view of the fixing bracket 4 shown in FIG. 1. FIG. 6 is a front sectional view showing another embodiment of the invention. FIG. 7 shows the slide member 28 shown in FIG.
FIG. FIG. 8 is a plan view of the slide member 28. FIG. 9 is a bottom view of the slide member 28. FIG. 10 is a front sectional view of the slide member 28. 1st
1 is an end view taken along line X I -X I of FIG. 6; FIG. FIG. 12 is a front view of the rotating yoke 24 shown in FIG. 6. FIG. 13 is a plan view of the rotating yoke 24. FIG. 14 is a front sectional view of the rotating yoke 24. FIG. 15 shows the downward surface of the slide member 28 and the rotating yoke 2.
4 is a plan view schematically showing a portion in contact with an upward surface of FIG. FIG. 16 is a front sectional view corresponding to FIG. 15. FIG. 17 is an illustrative plan view showing the state after rotation of the rotating yoke 24 from the state shown in FIG. 15. FIG. 18 is a front sectional view corresponding to FIG. 17. In the figure, 1 is a caster, 2 is a fixed bracket, 5 is a shaft, 6 is a rotating yoke, 7 is an axle, 8 is a wheel, A is a peak, B is an arcuate recess, C is a trough, and D is an arcuate convexity. Show part. Figure 8 2R Figure 13

Claims (3)

[Claims] (1) A fixed bracket fixed to an object moved by the caster; a shaft extending vertically and held by the fixed bracket; and a shaft held by the shaft, the upper end of which is the lower end of the fixed bracket. a rotary yoke that is provided so as to be rotatable around the shaft in a fitted state; and a rotary yoke that is rotatably supported by the rotary yoke via an axle that extends horizontally at a position horizontally offset from the shaft. wheels, and at the fitting portion of the fixed bracket and the rotating yoke, on the downward and upward surfaces of the fixed bracket and the rotating yoke that surround the shaft and abut each other from above and below, A caster in which concave and convex portions that can engage with each other are formed along a circle centered on the shaft. (2) The positional relationship of the uneven portions is selected such that they engage with each other when the object moved by the caster is in a straight traveling state.
Casters listed in section. (3) A slide member that is movable up and down along the shaft and a spring that urges the slide member to always move downward are housed in the fixed bracket, and the lower The caster according to claim 1 or 2, wherein the facing surface is formed on the slide member.