JPH07246802A - Caster mounting structure - Google Patents

Abstract

(57) [Summary] [Purpose] To realize a caster mounting structure that meets the demand for recycling and that also improves the stability of the casters during use. [Structure] When the upper end portion 31 and the lower end portion 32 of the caster shaft 3 are press-fitted into the shaft hole 11 opening on the lower surface of the leg blade 1 and the shaft hole 21 opening on the upper surface of the caster body 2, respectively. The fitting strength between the upper end portion 31 of the caster shaft 3 and the shaft hole 11 of the leg 1 is set to be larger than the fitting strength between the lower end portion 32 of the caster shaft 3 and the shaft hole 21 of the caster body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster mounting structure with improved convenience for replacement of casters.

[0002]

2. Description of the Related Art A caster is generally mounted by press-fitting an upper end portion and a lower end portion of a caster shaft into a shaft hole opened on a lower surface of a leg body and a shaft hole opened on an upper surface of a caster body. Is.

By the way, the casters may need to be replaced due to deterioration over time or damage, and the casters may have different purposes and uses such as when the place of use is changed from a panel to a tile and slip resistance becomes inadequate. Depending on the change, it may be necessary to replace with a different specification. Then, in consideration of such a convenience at the time of replacement, the conventional caster mounting structure has the lower end portion of the caster shaft and the caster body rather than the fitting strength between the upper end portion of the caster shaft and the shaft hole of the leg body. Set so that the fitting strength with the shaft hole is greater,
When replacing the caster, the caster shaft can be removed while it is still fitted in the shaft hole of the caster body. The purpose is to eliminate the problem that the caster shaft remains on the leg side or the caster body side, unify the removal direction, and improve the convenience of post-work.

FIG. 12 shows a concrete example of a caster mounting structure for that purpose. A protrusion c is formed in the vicinity of the inner end of the shaft hole b of the leg a, and the protrusion c and the upper end of the caster shaft d. The ring member f fitted externally through the circumferential groove e is engaged, and a projection i is formed near the inner end of the shaft hole h of the caster body g. The projection i and the caster shaft d are The circumferential groove j formed at the lower end is engaged. The outer diameter of the ring member f provided on the caster shaft d and the inner diameter of the shaft hole b of the leg body a are set to be substantially the same, and the outer diameter of the lower end portion of the caster shaft f and the inner diameter of the shaft hole h of the caster body g are set. Are set to have substantially the same diameter, so that the lower end of the caster shaft d and the shaft hole h of the caster body g are fitted more accurately than the fitting accuracy of the upper end of the caster shaft d and the shaft hole b of the leg a. The accuracy is increased so that the described effects can be achieved.

[0005]

However, in recent years, from the viewpoint of effective use of resources and environmental protection by reducing industrial waste, all articles have come to be recycled, and even the casters mentioned above are subject to recycling. The need for a review has arisen. That is, in the conventional caster mounting structure, as described above, the lower end portion of the caster shaft d and the shaft hole h of the caster body g are more accurate than the fitting accuracy between the upper end portion of the caster shaft d and the shaft hole b of the leg a. Since the mating accuracy of is high,
By the replacement, the caster shaft d is pulled out while being attached to the caster body g, and when it is not expected to be reused, it is actually discarded as it is. Therefore, there is a problem that the material of the caster shaft d is wasted, which is against the request for recycling. Further, when only the caster shaft d is to be reused, it is necessary to further separate the caster body g and the caster shaft d, and it is difficult to avoid an increase in the number of steps.

The present invention has been made in view of the above circumstances, and provides a caster mounting structure which meets the demand for recycling, which is a future subject, and which improves the stability of the casters during use. It is intended to be realized.

[0007]

The present invention uses the following constitution in order to achieve such an object.

That is, in the caster mounting structure according to the present invention, the upper end portion and the lower end portion of the caster shaft are press-fitted into the shaft hole opened on the lower surface of the leg body and the shaft hole opened on the upper surface of the caster body, respectively. In this caster mounting structure, the fitting strength between the upper end of the caster shaft and the shaft hole of the leg is set to be larger than the fitting strength between the lower end of the caster shaft and the shaft hole of the caster body. It is characterized by

Particularly, as a concrete structure for obtaining a strong degree of fitting between the upper end portion of the caster shaft and the shaft hole of the leg body in a detachable range, the shaft hole of the leg body is directed toward the lower surface. An inward taper surface is formed to expand the diameter, and the upper end of the caster shaft is pressed into contact with the inner circumference of the inward taper surface, where the inner diameter is approximately the same as the outer diameter of the caster shaft. An outer tapered surface that expands in diameter toward the portion, and a portion of the outer tapered surface having an outer diameter substantially the same as the inner diameter of the opening edge of the axial hole of the leg is pressed against the opening edge. To be

As another structure based on the same meaning, an inward taper surface whose diameter is expanded toward the lower surface is formed in the shaft hole of the leg, and the inward taper surface is formed at the upper end of the caster shaft. Examples include those that form an outward taper surface for taper fitting, and those that form a deformed portion formed by alternately connecting a large diameter portion and a small diameter portion in the axial direction at the upper end of the caster shaft. .

[0011]

With such a structure, when the caster is pulled out, the caster shaft is uniformly retained on the leg side while being held in the shaft hole of the leg body having a larger fitting strength.
The shaft hole of the caster body having a relatively small fitting strength and the caster shaft are disengaged, and the caster body is independently removed from the leg. Therefore, only by fitting a different caster body to the caster shaft again,
Since the replacement of the caster body is completed, it is possible to eliminate the waste caused by the continuous use of the caster shaft, and to adapt it to the effective use of resources, which is the purpose of recycling. Further, even when the caster body is discarded due to damage or the like, it is not necessary to separate the caster body from the caster shaft, so that the number of steps can be reduced.

In particular, according to the second aspect of the invention, the upper end of the caster shaft is in close contact with the inward taper surface formed in the shaft hole of the leg so as to bite into it, and at this time is formed at the lower end of the caster shaft. Since the outward taper surface also comes into close contact with the inner diameter of the shaft hole, a large fitting strength that cannot be obtained by simply engaging a part of the caster shaft with the shaft hole is obtained. Moreover, by supporting the caster shaft at both the upper end portion and the intermediate portion in this manner, it is possible to prevent the caster shaft from wobbling even if an inward taper surface is formed in the shaft hole, and it is possible to obtain a proper caster shaft. Can be held in a posture. Such an action is also obtained when the upper end of the caster shaft and the shaft hole of the leg are taper-fitted as in the third aspect. Further, even when a deformed portion formed by alternately connecting a large diameter portion and a small diameter portion in the axial direction is formed at the upper end portion of the caster shaft, the above structure is obtained in that the wobble prevention effect and the large fitting strength can be obtained. The action and effect according to are exhibited.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, this caster mounting structure includes a shaft hole 11 which is opened in the lower surface of the leg blade 1 which is a leg.
The upper end portion 31 and the lower end portion 32 of the caster shaft 3 are press-fitted into the shaft hole 21 opening on the upper surface of the caster body 2. Then, the fitting strength between the upper end portion 31 of the caster shaft 3 and the shaft hole 11 of the leg blade 1 is set to be larger than the fitting strength between the lower end portion 32 of the caster shaft 3 and the shaft hole 21 of the caster body 2. It is set.

More specifically, as shown in FIGS. 1 and 2, the leg blade 1 is made of a synthetic resin in which a cylindrical projection 12 is integrally formed on the lower surface, and the shaft hole 11 is formed. Is formed on the lower surface of the convex portion 12. Then, at the time of molding, the entire shaft hole 11 is molded so as to form an inward tapered surface 11a whose diameter increases toward the lower surface. This taper surface 1
The inner diameter of 1a is the minimum diameter φB and the maximum diameter φC.

On the other hand, the caster shaft 3 is made of an iron-based metal, and has a large-diameter collar 33 formed in the vicinity of the middle thereof.
The collar portion 33 divides the caster shaft 3 into an upper end portion 31 and a lower end portion 32. The outer diameter of the upper end portion 31 is φA (B <
A <C). Further, the upper end portion 3 adjacent to the collar portion 33
The outer periphery of 1 is formed with an outward taper surface 31a having a minimum diameter φA and a maximum diameter φC + α and expanding toward the lower end portion 32, and a circumferential groove 31b is provided in the outer periphery near the upper end surface, A circumferential groove 32a is formed on the outer periphery near the lower end surface, and a spherical recess 32b is formed on the lower end surface.

On the other hand, in the caster body 2, as shown in FIGS. 1 to 3, the shaft hole 21, the cover 22, the ribs 23 and the boss hole 24 are integrally molded with resin, and the horizontal shaft 25 is provided in the boss hole 24. A pair of wheels 26 are axially mounted through the shaft. The shaft hole 21 has an outer diameter A of the caster shaft 3.
It has an inner diameter slightly larger than This shaft hole 2
A cylindrical portion 27 is formed on the outer periphery of the cylinder 1 so that the axes thereof coincide with each other. The cylindrical portion 27 is set to a size such that the convex portion 12 of the leg blade 1 can be fitted relatively closely thereto. Further, the shaft hole 21 has a spherical seat 21a for a bearing formed at its inner end, and projections 21b are formed at one or several places along the circumferential direction on the inner periphery near the inner end thereof. is doing.

Next, the procedure until the caster is put into the mounting state shown in FIGS. 4 and 5 will be described. First, the upper end portion 31 of the caster shaft 3 is pressed into the leg blade 1. At this time, the upper end portion 31 is located on the inner circumference of the inward taper surface 11a and has a diameter substantially the same as the outer diameter φA of the caster shaft 3.
The caster shaft 3 is slightly advanced by contacting with the inner circumference of 1 and further pushing from there, and the tip of the upper end 31 is strongly pressed into the shaft hole 11. That is, while the caster shaft 3 is made of iron-based metal, the leg blades 1 are made of resin, so the upper end 31 of the caster shaft 3 deforms the inner circumference of the shaft hole 11 while It sticks so as to bite into the inner circumference of the shaft hole 11. In particular, in this embodiment, since the circumferential groove 31b is provided in the vicinity of the upper end surface, a part of the deformed resin swells and enters the circumferential groove 31b, and a biting effect is produced. Therefore, the holding force for the caster shaft 3 is further increased. At the same time that the upper end portion 31 is attached to the inner circumference of the shaft hole 11, the opening edge 11 of the shaft hole 11 of the leg blade 1 of the outward taper surface 31a of the caster shaft 3 is substantially at the same time.
When the caster shaft 3 is further pushed in, the outward taper surface 31a is deformed in the vicinity of the opening edge 11b at the same time when the caster shaft 3 is pushed further in such a manner that a portion having an outer diameter substantially equal to the inner diameter φC of b is abutted on the opening edge 11b. It comes into close contact so as to bite into the shaft hole 11.

Next, the lower end 32 of the caster shaft 3 is pressed into the caster body 2. In this case, the caster shaft 3 is initially inserted relatively gently to a certain position, and the circumferential groove 3
Only when the outer circumference on the lower end side of 2a gets over the projection 21b provided on the inner circumference of the shaft hole 21, press-fitting is practically performed.
Then, the protrusion 21b is the circumferential groove 32 of the caster shaft 3.
At the same time when it enters a, the spherical shape 32 of the caster shaft 3
b is attached to the spherical seat 21a of the shaft hole 21 to support the load applied to the caster shaft 3, and the fitting between the caster shaft 3 and the caster body 2 is completed.
As described above, in the present embodiment, the fitting strength between the upper end portion 31 of the caster shaft 3 and the shaft hole 11 of the leg blades 1 is determined by the lower end portion 32 of the caster shaft 3 and the shaft hole 21 of the caster body 2. It is set to a state relatively larger than the fitting strength.

With such a caster mounting structure,
When pulling out the caster body 2, as shown in FIGS. 6 and 7, the caster shaft 3 has a leg blade 1 with a larger fitting strength.
The caster body 2 remains on the leg blade 1 side while being retained in the shaft hole 11 of the caster body 2, and the caster body 2 is disengaged from the shaft hole 21 of the caster body 2 having a relatively small fitting strength.
Will be removed by itself. Such an action is reproducibly exhibited as long as the above-mentioned fitting strength relationship is maintained. Therefore, according to the caster mounting structure of this embodiment, the replacement of the caster body 2 is completed only by fitting the different caster body 2 to the caster shaft 3 again, and the caster shaft 3 can be continuously replaced. It is possible to eliminate waste caused by use, and eventually adapt to effective use of resources, which is the purpose of recycling. Further, even when the caster main body 2 is discarded due to damage or the like, the work of separating the caster main body 2 and the caster shaft 3 becomes unnecessary, so that the number of steps for post-processing can be reduced. In this way, by supporting the caster shaft 3 at both the upper end portion 31 and the intermediate portion in a two-sided manner,
Even if the inwardly tapered surface 11a is formed in the shaft hole 11, wobble of the caster shaft 3 can be reliably prevented, and the caster shaft 3 can be held in an appropriate posture. That is, in the present embodiment, not only the inconvenience due to the taper surface can be eliminated, but the stability of the caster is further improved by fixing the upper end portion 31 of the caster shaft 3 as compared with the conventional mounting structure. It will be further enhanced. In particular, in this embodiment, the convex portion 12 of the leg blade 1 is fitted into the cylindrical portion 27 of the caster body 2 to further improve the stability of the caster as a whole.

The specific structure of each part is not limited to the above-described embodiment, but various modifications can be made without departing from the spirit of the present invention. For example, as another specific configuration for obtaining a strong degree of fitting between the upper end of the caster shaft and the shaft hole of the leg body in a detachable range, as shown in FIG. An inward taper surface 111a is formed in the hole 111 so as to expand its diameter toward the lower surface, and an outer taper surface 131a is fitted to the upper end portion 131 of the caster shaft 103 by the inward taper surface 111a.
May be formed. Even with such a configuration, the same operational effects as those of the above-described embodiment can be obtained. Further, as shown in FIG. 9 or FIG. 10, the deformed portion 231 in which the large diameter portion and the small diameter portion are alternately continuous in the upper end portions 231 and 331 of the caster shafts 203 and 303 in the axial direction.
It is also effective to form a and 331a. According to this structure, the fitting strength with the shaft hole can be easily increased without forming the shaft hole with a tapered surface. Further, as a modification of FIG. 2, a convex surface 11c may be formed in the shaft hole 11 of the leg 1 as shown in FIG. That is, in the above-described embodiment, the upper end portion 31 of the caster shaft 3 is attached to the shaft hole 11
A part of the resin deformed when it is press-fitted is bulged into the circumferential groove 31b provided in the caster shaft 3 so that a biting effect is obtained. If the convex surface 11c is formed, the circumferential groove 31b can be engaged with the convex surface 11c to reliably increase the holding force for the caster shaft 3. In this case, assuming that the axial dimension of the convex surface 11c is E and the axial width of the circumferential groove 31b is F, a relationship of E> F is set, and when the caster mounting is completed, the convex surface 11c and the circumferential groove 31b are effectively separated from each other. If the pressure contact between the two is made to be the strongest, the depth of the pressure contact is positively specified in addition to the above-mentioned effect of increasing the holding force, and the dimensional relationship with other pressure contact points is clarified, and There are also effects such as an advantage. Further, although not shown, in the embodiment described above, the circumferential groove at the lower end of the caster shaft is shown in FIG.
The ring member f shown in 1 may be externally fitted. In other words, the present invention is not limited to any structure as long as the fitting strength between the upper end of the caster shaft and the shaft hole of the leg can be set larger than the fitting strength between the lower end of the caster shaft and the shaft hole of the caster shaft. It is good, and when considering the configuration for that, it can be set variously depending on the balance between the strength due to the fitting structure between the shaft and the hole and the strength due to the fitting accuracy between them. is there.

[0022]

As described above, according to the caster mounting structure of the present invention, the upper end portion and the lower end portion of the caster shaft are respectively provided in the shaft hole opened in the lower surface of the leg and the shaft hole opened in the upper surface of the caster body. When press-fitting the part, make sure that the fitting strength between the upper end of the caster shaft and the shaft hole of the leg is greater than the fitting strength between the lower end of the caster shaft and the shaft hole of the caster body, contrary to the conventional method. Is set to.
Therefore, when pulling out the casters, it is possible to uniformly remove only the caster main body from the leg while leaving the caster shaft on the leg side, and when replacing the caster main body, it is wasteful due to continuous use of the caster shaft. It can be resolved and can be adapted to effective use of resources, which is the purpose of recycling. Further, even when the caster main body is discarded due to damage or the like, there is no need to separate the caster main body from the caster shaft, so that the number of post-processing steps can be reduced. Further, in the present invention, since the upper end portion of the caster shaft is securely fixed, there is an additional effect that the stability of the caster is further enhanced as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention before a caster is attached.

FIG. 2 is a sectional view of the same main part.

FIG. 3 is a cross-sectional view showing the internal structure of the caster body in the embodiment.

FIG. 4 is a perspective view showing a state after mounting casters in the embodiment.

FIG. 5 is a sectional view of the same main part.

FIG. 6 is a perspective view showing a state where the casters are removed again in the embodiment.

FIG. 7 is a sectional view of the same main part.

FIG. 8 is a sectional view of an essential part corresponding to FIG. 5, showing another embodiment of the present invention.

FIG. 9 is a cross-sectional view of an essential part corresponding to FIG. 5, showing still another embodiment of the present invention.

FIG. 10 is a view showing still another modified example of the caster shaft according to the present invention.

FIG. 11 is a sectional view corresponding to FIG. 2 showing still another embodiment of the present invention.

FIG. 12 is a sectional view corresponding to FIG. 2 showing a conventional example.

[Explanation of symbols]

 1, 101 ... Leg body (leg blade) 2 ... Caster body 3, 103, 203, 303 ... Caster shaft 11, 111 ... Shaft hole 11a ... Inward tapered surface 11b ... Opening edge 21 ... Shaft hole 31, 131, 231, 331 ... upper end 31a ... outward taper surface 32 ... lower end 111a ... inward taper surface 131a ... outward taper surface 231a, 331a ... deformed portion

Claims (4)

[Claims] 1. A caster mounting structure in which an upper end portion and a lower end portion of a caster shaft are press-fitted into a shaft hole opened on a lower surface of a leg body and a shaft hole opened on an upper surface of a caster body, respectively. Caster mounting characterized in that the fitting strength between the upper end of the shaft and the shaft hole of the leg is set to be larger than the fitting strength between the lower end of the caster shaft and the shaft hole of the caster body. Construction. 2. An inwardly tapered surface that expands toward the lower surface is formed in the shaft hole of the leg, and the upper end of the caster shaft is the inner circumference of the inwardly tapered surface and is substantially the same as the outer diameter of the caster shaft. While making pressure contact with the portion having the inner diameter, an outward taper surface that expands toward the lower end is formed in the vicinity of the middle of the caster shaft, and of this outward taper surface, it is approximately the same as the inner diameter of the opening edge of the shaft hole of the leg. The caster mounting structure according to claim 1, wherein portions having the same outer diameter are brought into pressure contact with the opening edge. 3. The shaft hole of the leg body is formed with an inward taper surface that expands in diameter toward the lower surface, and an upper taper end of the caster shaft is formed with an outward taper surface that is taper-fitted to the inward taper surface. The caster mounting structure according to claim 1, wherein: 4. The caster mounting structure according to claim 1, wherein a deformed portion is formed at the upper end portion of the caster shaft by alternately connecting a large diameter portion and a small diameter portion in the axial direction.