Two-wheeled hollow caster and method for manufacturing the same

Abstract

An object of the present invention is to provide a two-wheel hollow caster having a simple configuration that can easily enhance slidability. 【Solution means】 One two-wheel hollow caster 1 according to the present invention includes a main body 13 having a hollow portion 13A, a substantially cylindrical pipe member 11P disposed so as to penetrate the hollow portion 13A, a pair of wheels 15, 15 attached to both ends of the pipe member 11P, and a single bearing 11B sandwiched between the main body 13 and the pipe member 11. Therefore, a single bearing 15 can be shared by the pair of wheels 15, 15, and it is also easy to enhance the slidability of the pair of wheels 15, 15 by using a ball bearing as the single bearing 15.

Description

Technical Field

[0001] The present invention relates to casters attached to the bottom side of shopping carts, trolleys, wagons, tables, chairs, cabinets, shelves, etc. used in facilities such as shopping malls, supermarkets, airports, etc., vehicles such as wheelchairs and baby carriages, and other heavy objects. In particular, it relates to a double-wheel hollow caster in which the wheels are double and hollow.

Background Art

[0002] For example, double-wheel hollow casters are disclosed in FIGS. 1 to 3 of Patent Document 1. This double-wheel hollow caster has a ring-shaped holder 3 attached to a ring-shaped main body 1, and a pair of wheels 2, 2 are attached to both sides of the holder 3. Dry bearings 5 are sandwiched between the holder 3 and the pair of wheels 2, 2, and between the main body 1 and the pair of wheels 2, 2, respectively. Such a double-wheel hollow caster has the merit that when a load is applied, the pair of wheels 2, 2 are less likely to open in a V shape, so the possibility of parts being damaged is lower than that of a non-hollow double-wheel caster.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the double-wheel hollow caster described in FIGS. 1 to 3 of Patent Document 1 includes a total of four dry bearings, two on the left and two on the right. In order to improve the sliding (sliding property) of each of these dry bearings, grease is required, or the grease has to be omitted and the poor sliding (sliding property) has to be tolerated.

[0005] Therefore, an object of the present invention is to provide a two-wheel hollow caster that is easy to enhance slidability and has a simple structure.

Means for Solving the Problems

[0006] In order to solve the above problems, a two-wheel hollow caster according to the present invention includes a main body having a hollow portion, a substantially cylindrical pipe member disposed so as to penetrate the hollow portion, a pair of wheels attached to both ends of the pipe member, and a single bearing sandwiched between the main body and the pipe member.

[0007] In a two-wheel hollow caster according to the present invention for solving the above problems, one and the other of the pair of wheels may each include an inner ring attached to one end of the pipe member and an outer ring attached around the inner ring.

[0008] In a two-wheel hollow caster according to the present invention for solving the above problems, the bearing may be a shielded ball bearing.

[0009] In a two-wheel hollow caster according to the present invention for solving the above problems, the ball bearing may be made of stainless steel.

Effects of the Invention

[0010] The two-wheel hollow caster according to the present invention includes a main body having a hollow portion, a substantially cylindrical pipe member disposed so as to penetrate the hollow portion, a pair of wheels attached to both ends of the pipe member, and a single bearing sandwiched between the main body and the pipe member. Therefore, a single bearing can be shared by a pair of wheels, and by using a ball bearing as the single bearing, it is easy to enhance the slidability of the pair of wheels. Accordingly, according to the present invention, there is an effect that a two-wheel hollow caster with a simple configuration that can easily enhance slidability is realized. Further, since the two-wheel hollow caster according to the present invention shares a single bearing for a pair of wheels, there is also an effect that the number of parts is small and assembly is easy.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0012] Hereinafter, a preferred embodiment of the two-wheel hollow caster according to the present invention will be described with reference to the drawings. The two-wheel hollow caster according to the present embodiment is, for example, a caster for a chair. However, this two-wheel hollow caster can also be used as a caster for moving heavy objects other than chairs.

[0013] Fig. 1(A) is a perspective view of the two-wheel hollow caster according to the present embodiment, Fig. 1(B) is a perspective view of the two-wheel hollow caster viewed from a direction different from Fig. 1(A), Fig. 2 is an exploded view of the two-wheel hollow caster, Fig. 3(A) is an assembly view of the wheels, Fig. 3(B) is an assembly view around the bearing, Fig. 4(A) is a side view of the two-wheel hollow caster, and Fig. 4(B) is a sectional view taken along line A-A of Fig. 4(A).

[0014] As shown in Figs. 1 and 2, the two-wheel hollow caster 1 according to the present embodiment includes a main body 13 having a hollow portion 13A, a substantially cylindrical pipe member 11P disposed so as to penetrate the hollow portion 13A, a pair of wheels 15, 15 attached to both ends (around) of the pipe member 11P, a bearing portion 13B provided with the same member as the main body 13 at a position deviated from the hollow portion 13A of the main body 13, a shaft 11 fitted to the bearing portion 13B, and a cover 12 covering the fitting portion between the main body 13 and the shaft 11.

[0015] One of the pair of wheels 15, 15 of this two-wheel hollow caster 1 includes an inner ring 15in attached around one open end of the pipe member 11P as shown in Figs. 2 and 3(A), and an outer ring 15out attached around the inner ring 15in. When attaching the inner ring 15in around the pipe member 11P, the fitted portion 15in-1 (Fig. 2) inside the inner ring 15in is fitted to the fitting portion 11P-1 (Fig. 2) around the pipe member 11P.

[0016] Similarly, the other of the pair of wheels 15, 15 of the two-wheel hollow caster 1 includes an inner ring 15in attached around the other open end of the pipe member 11P as shown in Figs. 2 and 3(A), and an outer ring 15out attached around the inner ring 15in. When attaching the inner ring 15in around the pipe member 11P, the fitted portion 15in-1 (Fig. 2) inside the inner ring 15in is fitted to the fitting portion 11P-1 (Fig. 2) around the pipe member 11P.

[0017] Note that the shape of the peripheral wall (ring portion) of the hollow portion 13A of the main body 13 is an asymmetric shape in the vertical direction where the thickness in the radial direction is larger on the top side than on the floor surface side. When the wheels 15, 15 are attached, the upper ends of the peripheral wall (ring portion) of the main body 13 and the upper ends of the wheels 15, 15 are approximately at the same height. However, the lower end of the peripheral wall (ring portion) of the main body 13 is located above the lower ends of the wheels 15, 15. Therefore, when the wheels 15, 15 are installed on the floor surface, the lower end of the peripheral wall (ring portion) of the main body 13 is in a floating state from the floor surface.

[0018] And, as shown in Fig. 3(B), a single bearing 11B is sandwiched between the main body 13 and the pipe member 11P, and this bearing 11B is shared by the pair of wheels 15, 15. The inner circumference of the inner ring of the bearing 11B is fixed to the pipe member 11P, and the outer circumference of the outer ring of the bearing 11B is fixed to the main body 13. Here, the fixing method of the inner ring of the bearing 11B to the pipe member 11P and the fixing method of the outer ring of the bearing 11B to the main body 13 are as follows, for example. That is, first, the bearing 11B is inserted into the mold for molding the pipe member 11P and injection molded to integrate the inner circumference of the inner ring of the bearing 11B with the pipe member 11P. Next, the integrated bearing 11B and pipe member 11P are inserted into the mold for molding the main body 13 and injection molded to integrate the outer circumference of the outer ring of the bearing 11B with the main body 13. According to such a fixing method, since the members are integrated in the molding process, it is possible to reduce the number of parts, miniaturize the parts, and improve the strength of the parts as compared with the case of assembling the members in the post-process of the molding process. Also, the bearing 11B of the present embodiment is a stainless steel sealed ball bearing. Although it is more costly than a dry bearing, it has the merit of high slidability and does not require grease.

[0019] Note that the material of the shaft 11 is a metal such as iron, the material of the cover 12 is a synthetic resin such as PA6 (6 nylon resin), the material of the main body 13 is a synthetic resin having both wear resistance and strength such as PA6GF30 (polyamide 6 glass fiber 30%), the material of the pipe member 11P is a synthetic resin having both lubricity and strength such as POM-GF30% (polyoxymethylene POM material polyoxymethylene), the material of the inner ring 15in is a synthetic resin such as PA6 (6 nylon resin), and the material of the outer ring 15out is a synthetic resin having appropriate grip such as TPU (thermoplastic polyurethane elastomer). Note that these materials are not limited to these, and appropriate materials can be adopted according to the functions of each member.

[0020] As described above, in the double-wheel hollow caster 1 according to the present embodiment, a single bearing 11B is shared by a pair of wheels 15, 15, and a ball bearing is used as this bearing 11B. Therefore, it is easy to improve the slidability of the pair of wheels 15, 15, and its configuration is simple. Further, in the double-wheel hollow caster 1 according to the present embodiment, a single bearing 11B is shared by a pair of wheels 15, 15, and screws or the like are not used, so the number of parts is small and assembly is easy.

[0021] Note that the present invention is not limited to the above-described embodiments, and the components can be appropriately deformed and embodied without departing from the gist thereof. Further, various inventions can be formed by appropriately combining a plurality of components disclosed in each embodiment. For example, at least one of the diameter size and width size of the pair of wheels 15, 15, or the ratio of the diameter size to the width size can be changed according to the use of the caster or the like.

Explanation of Signs

[0022] 1 Double-wheel hollow caster 11 Shaft 12 Cover 13 Main body 13A Hollow portion 13B Bearing part 11P Pipe member 11P-1 Fitting part 11B Bearing 15 Wheel 15out Outer ring 15in Inner ring 15in-1 Fitted part

Claims

1. A body having a hollow portion; A substantially cylindrical pipe member disposed so as to penetrate the hollow portion; a single bearing sandwiched between the body and the pipe member, the single bearing having an outer ring integrally formed with the body and an inner ring integrally formed with the pipe member; a pair of wheels attached to both open ends of the pipe member protruding outwardly from the body; Equipped with A dual-wheel hollow caster having no bearing other than the single bearing.

2. The dual-wheel hollow caster according to claim 1, Each of the pair of wheels is an inner ring attached to one end of the pipe member; an outer ring attached around the inner ring; A dual-wheel hollow caster comprising:

3. The dual-wheel hollow caster according to claim 1, The bearing is It is a shielded ball bearing. A dual-wheel hollow caster characterized by:

4. The dual-wheel hollow caster according to claim 3, The ball bearing is made of stainless steel. A dual-wheel hollow caster characterized by:

5. A body having a hollow portion; A substantially cylindrical pipe member disposed so as to penetrate the hollow portion; a single bearing sandwiched between the body and the pipe member, the single bearing having an outer ring integrally formed with the body and an inner ring integrally formed with the pipe member; a pair of wheels attached to both open ends of the pipe member protruding outwardly from the body; A method for manufacturing a dual-wheel hollow caster having no bearing other than the single bearing, a step of inserting the bearing into a molding die for the pipe member and injection molding the bearing to integrate the inner ring of the bearing with the pipe member; a step of inserting the integrated bearing and the pipe member into a mold for molding the main body and performing injection molding to integrate the outer ring of the bearing with the main body; A method for manufacturing a dual-wheel hollow caster, comprising:

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