Furniture caster, method for manufacturing the same, furniture, and chair

Abstract

To provide a caster with a simple structure that can suppress a movement of a chair by becoming unrotatable when a person sits on it.SOLUTION: A caster 7 includes: a rotating shaft 22; an inner ring part 23 fitted thereto; and an outer ring part 24 fitted to the inner ring part 23 from an outside. The outer ring part 24 is made of elastomer material, for example, and consists of: an inner rim layer 27 and an outer rim layer 28 which each have a thin-wall-shape and high density; and a compression-deformable layer 29 with a three-dimensional lattice structure located between them. The compression-deformable layer 29 is configured to have elastic strength that allows it to collapse and deform significantly when a person sits on it. Thus, when the person is seated on a chair, the chair is restrained from moving, and a user can perform his / her duty or work in a stable manner. Since a ground contact area with a floor surface F is increased, the chair is less likely to be damaged even if the floor is wooden flooring.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to casters used for furniture such as chairs, a method for manufacturing the same, furniture provided with the casters, and a chair as an example thereof.

Background Art

[0002] It is widely practiced to provide casters for furniture such as chairs and tables. Casters are for facilitating the movement of furniture and are provided with rollers (wheel bodies) that roll on the floor. Generally, casters rotatably hold the wheel bodies with horizontal support shafts, and there are types that can horizontally swivel and types that cannot horizontally swivel.

[0003] Although casters are provided to facilitate the movement of furniture such as chairs, in the case of a chair, it may be better not to move when a person is seated. For example, when installed on a flooring floor or a resin tile floor, since the roller easily rotates with only a slight force applied to the chair, it may be preferable not to move it in order to maintain the stability of the body. Also, from the point of preventing damage to the floor, it may be preferable not to move it randomly.

[0004] Also, in the case of a chair used in a set with a so-called study desk, since it is necessary to appropriately maintain the positional relationship between the user (child) and the desk, it is preferable that the chair does not move at a predetermined position. Furthermore, in the case of a so-called pipe chair that is used with multiple legs arranged side by side at a venue such as a training session, casters are often provided for ease of movement, but in this case, it is necessary to be kept in a state where it does not move easily and is arranged in the usage state.

[0005] Therefore, it has been proposed to make the chair movable while maintaining the function of the casters in a state where a person is not seated, and to make the chair immovable by suppressing the function of the casters when a person sits down. As an example, Patent Document 1 discloses that the casters are supported on the legs of the chair via springs, and when a person sits down, the seat legs are lowered against the springs and brought into contact with the floor, thereby holding the chair immovable. Further, as a means for preventing damage to the floor, as disclosed in Patent Document 2, it has also been proposed to coat the outer periphery of the roller with rubber or an elastomer.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The chair of Patent Document 1 maintains the ease of movement in the non-seated state while restricting movement in the seated state. However, since the casters must be held so as to be able to move up and down, the structure becomes complicated and the cost increases. In addition, since a space for hiding the casters is required on the legs, the applicable objects are limited and there is a problem of lack of versatility.

[0008] On the other hand, the one in Patent Document 2 can suppress damage to the floor, but since the rotation of the roller constituting the caster is not suppressed, it cannot meet the demand for suppressing the movement of the chair.

[0009] The present invention has been made against this background, and relates to a caster that can hold a furniture movable in an unloaded state and suppress movement in a loaded use state, and discloses a technology that can be realized with a simple structure and is also excellent in design.

Means for Solving the Problems

[0010] The present disclosure includes various technologies with different aspects. A typical example thereof will be described below.

[0011] The first aspect relates to a caster disposed at the lower end of furniture, and this caster "is a caster disposed at the lower end of furniture, a support shaft portion rotatable around an axis in a horizontal posture, and disposed outside the outer periphery of the support shaft portion T-shaped joint and a grounding portion, wherein the grounding portion Installation is crushed to such an extent that rotation is suppressed when a load equal to or greater than a certain value is applied It is elastically deformable so as to allow elastic deformation, and as a structure that allows elastic deformation and It includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and joining a large number of thin element bodies are three-dimensionally arranged and intertwined. has such a configuration.

[0012] In this configuration, when a load is applied to the furniture, the wheel body constituting the caster is compressed and deformed by itself to make surface contact with the floor, and rotation is suppressed. As a result, the movement of the furniture is also suppressed. And in this configuration, since it is not necessary to add other members to the caster or the furniture, the structure does not become complicated, it can cope with various furniture, and it has excellent versatility. Briefly, it can be freely exchanged with the caster of existing furniture and has excellent flexibility.

[0013] Further, since the grounding portion is greatly elastically deformed to make surface contact with the floor, the load acting on the floor per unit area is extremely low, and damage to the floor can be prevented or significantly suppressed. Therefore, it is suitable for furniture used on a flooring floor or a resin carpet floor. In addition, when used for the caster of a chair, when a person sits down, the caster is elastically deformed to give cushioning properties, so there is also an advantage that the sitting comfort can be improved.

[0014] Generally, a caster has a structure in which a wheel body is fixed to a rotatable support shaft. However, the caster of the present disclosure includes both a structure in which the wheel body has a single structure and at least a portion thereof from its outer periphery serves as a grounding portion, and a structure in which the wheel body is composed of an inner wheel portion and an outer wheel portion and the outer wheel portion serves as the grounding portion. Further, although the support shaft portion is generally made of metal and has an independent structure, it can also be integrally formed on the inner peripheral portion of the wheel body.

[0015] A second aspect of the present disclosure embodies the first aspect, and this aspect is "The grounding portion has a thin outer rim layer constituting its outer periphery and a thick compression deformation layer located inside the outer rim layer The compression deformation layer is composed of the three-dimensional lattice structure. When a load equal to or greater than the set value is applied, the outer rim layer extends and deforms so as to be in surface contact with the floor surface, and the compression deformation layer is crushed and deformed in the vertical direction." It has such a configuration.

[0016] In the caster of the second aspect, since the outer rim layer can have a higher density than the compression deformation layer and the outer peripheral surface can be formed smoothly, it is possible to prevent dust that has fallen on the floor from being transferred and remaining attached, and to maintain a good appearance. Also, if the compression deformation layer directly hits the floor surface, there is a concern that when a horizontal external force acts on the furniture, the deformation will easily progress in the circumferential direction and it will be easy to rotate. However, with a high-density outer rim layer as in the second aspect, the outer rim layer strongly acts as a resistance to rotation, so it has an excellent effect of suppressing the rotation of the caster.

[0017] A third aspect of the present disclosure relates to the structure of the compression deformation layer. In the second aspect, "The compression deformation layer includes a three-dimensional structure having a large number of independent spaces or an intruded continuous space As described above, the three-dimensional structure is the three-dimensional lattice structure. " It has such a configuration.

[0018] In this configuration, the compression deformation layer can be deformed into a desired state by adjusting the porosity, selecting materials, etc. As a result, it is possible to realize that the outer rim layer is deformed flatly and makes surface contact with the floor surface over a wide area, thereby ensuring the rotation suppression function of the caster. In addition, since the three-dimensional structure can be visually recognized from the outside, it has an appearance that is not found in conventional casters and is excellent in terms of design.

[0019] The fourth aspect is an independent claim standing side by side with claim 1. 「 A caster disposed at the lower end of a furniture, It has a support shaft portion rotatable about an axis in a horizontal posture and a grounding portion disposed outside the outer periphery of the support shaft portion. The grounding portion It has a thin outer rim layer constituting its outer periphery and a thick compression deformation layer located inside the outer rim layer. When a load equal to or greater than a set value is applied, the outer rim layer extends and deforms so as to be in surface contact with the floor surface, and the compression deformation layer is crushed and deformed in the vertical direction. The compression deformation layer includes a three-dimensional structure having a large number of independent spaces or recessed continuous spaces. The three-dimensional structure It includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and joining a large number of thin element bodies are three-dimensionally arranged and intertwined. It adopts the configuration of

[0020] This configuration And the configuration of claim 1 In this case, the compression deformation layer is composed of a large number of Thin element bodies Although it is composed, Thin element bodies Since they elastically deform while restricting each other, the load can be evenly distributed and the quality can be stabilized. In addition, Thin element bodies Since the elastic strength and the like can be easily changed by adjusting the thickness, posture, arrangement density, etc. of

[0023] In the fifth aspect of the present disclosure, in any one of the first to 4 aspects, a single-seat chair is specified as a furniture, and the caster for this chair is "It is set to an elastic strength that collapses and deforms to such an extent that rotation is suppressed by a total load of 20 kg or more and 60 kg or less including the own weight of the chair." It has the configuration of

[0024] There are various types of chairs with casters for single occupancy, such as swivel chairs commonly used in offices and the aforementioned pipe chairs. However, even if they are heavy, their weight is at most about 15 kg. On the other hand, the weight of the average adult using the chair varies greatly among individuals, but generally speaking, it can be said that it is 40 kg or more. And in the sixth aspect, as the total load of the group of casters ranges from 20 Kg to 60 Kg, the compression deformation layer of each caster is crushed and deformed. Therefore, it can accommodate almost all chairs with different weights and users with different weights, and has high versatility.

[0025] This disclosure also includes a manufacturing method. An example thereof will be presented as the 6 aspect. That is, the manufacturing method of the 6 aspect is " A method for manufacturing a caster for furniture having a support shaft portion rotatable about an axis in a horizontal posture and a grounding portion disposed outside the outer periphery of the support shaft portion and capable of being crushed and deformed, wherein the grounding portion is set to an elastic strength that is crushed and deformed to such an extent that rotation is suppressed when a load equal to or greater than a set value is applied. A step of manufacturing the grounding portion; A step of attaching the grounding portion to a support; It has The step of manufacturing the grounding portion It includes processing of a compression deformation layer of a three-dimensional lattice structure, processing of an inner rim layer integrally continuous with the inner periphery of the compression deformation layer, and processing of the outer rim layer integrally continuous with the outer periphery of the compression deformation layer, and these processes are performed in series using a 3D printer. " configured as such.

[0026] Injection molding cannot produce the form that has entered due to the constraints of mold release, but a 3D printer can easily produce a form that has entered complexly. Therefore, it is possible to easily realize a caster with excellent elasticity. Also, while the inner rim layer is a necessary part for attaching to the inner ring portion, and the outer rim layer is a necessary part as a grounding portion, a 3D printer can manufacture these elements with different densities in series, so it is possible to surely provide a caster with excellent quality. Note that, as an example of the manufacturing of a structure using a 3D printer, it is also disclosed in, for example, Japanese Patent Application Laid-Open No. 2020-59278 and International Publication WO2020 / 075722.

[0027] The 7 aspect of this disclosure relates to another version of a caster for supporting furniture, and this caster "It has a spherical receiving body that opens downward, and a spherical roller that is rotatably held and cannot be removed while being elastically deformable, covered from above by the spherical receiving body, The spherical roller has a structure that elastically deforms so as to be crushed to such an extent that rotation is suppressed when a load equal to or greater than a set value is applied. , As a structure that allows elastic deformation , It includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and joining a large number of thin element bodies are three-dimensionally arranged and intertwined. " It has such a configuration.

[0028] There are casters with spherical (ball-shaped) rollers that roll on the floor surface in any direction. This type does not require a support shaft and has a simple structure, and the present disclosure can also be applied to this type. And although it is impossible to form the internal structure of the spherical roller into a three-dimensional lattice structure by an injection molding method, by using a 3D printer as shown in the 6 aspect, a spherical and highly elastic (compression-deformable) roller can be easily manufactured.

[0029] The present disclosure includes furniture and a chair as an example thereof. That is, as shown in the 8 aspect, the furniture has a configuration including the caster described in any one of claims 1~4,7 and legs supported on the floor via the caster, and as shown in the 9 aspect, the chair has a configuration of "a caster according to any one of claims 1~4,7 is attached to the legs that support the seat."

Advantages of the Invention

[0030] The invention according to the present disclosure exhibits the above-described effects.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0032] (1). Outline of the Chair Next, embodiments of the present invention will be described with reference to the drawings. Hereinafter, it is applied to furniture and its casters. Hereinafter, the terms "front and rear" and "left and right" are used to specify directions. For the chair, the front and rear and left and right are defined as the directions seen from a person sitting normally, and for the caster, the axial direction is defined as the front and rear direction, and the horizontal direction orthogonal to the axis is defined as the left and right direction.

[0033] In FIG. 1(A), a swivel chair is shown, and in (C), a pipe chair used side by side in a conference room, a lecture room, etc. is shown. The swivel chair in FIG. 1(A) has a seat 1, a reclining backrest 2, and legs 3. The legs 3 have a leg support 4 made of a gas cylinder and branch rods 5 extending radially from the lower end of the leg support 4. At the tip of each branch rod 5, a boss portion 6 opening downward is formed, and casters 7 and 8 are attached to each boss portion 6.

[0034] On the other hand, the chair shown in FIG. 1(C) has legs 3 having left and right front legs 9 and rear legs 10, a seat 1 pivotally attached to the legs 3 so as to be able to bounce up and rotate, and a backrest 2 attached to the upper ends of the rear legs 10. Boss portions 6 opening downward in a vertical posture are formed at the lower ends of each of the legs 9, 10, and casters 8 are attached to the boss portions 6. A left-right longitudinal connecting shaft (not shown) is mounted between the upper ends of the left and right front legs 9, and the seat 1 is rotatably held by the connecting shaft.

[0035] In FIG. 1(C), the upper end portions of the front and rear legs 9, 10 are connected via a joint 12, and an armrest 13 and a backrest 2 are attached to the joint 12. The member indicated by reference numeral 14 in FIG. 1(C) is a receiving bar (stopper) that holds the seat 1 in a horizontal posture (deployed posture) and reinforces the left and right legs 9.

[0036] The caster 7 of the first embodiment shown in FIG. 1(B) has a center support 15 and a pair of left and right wheel bodies 16 disposed on both left and right sides thereof. A vertical shaft 17 is erected upward at a portion of the center support 15 that is separated from the rotation axis of the wheel body 16 in the front-rear direction. Therefore, the caster 7 is of a type that rotates horizontally.

[0037] The vertical shaft 17 is rotatably and non-removably held by the center support portion 15, and the vertical shaft 17 is fitted into the boss portion 6 of the leg portion 3 of the chair from below. A flange 18 for supporting the boss portion 6 is formed on the vertical shaft 17. Note that the vertical shaft 17 may be of a bolt type. In this case, the flange 18 is a hexagonal head to which a wrench engages.

[0038] The caster 7 of the second embodiment shown in FIG. 1(D) is basically the same as the caster 7 of FIG. 1(B), and the difference is that a cover 19 covering the left and right wheel bodies 16 is integrally formed on the center support portion 15. In any case, the center support portion 15 is made of synthetic resin, but a metal die-cast product can also be adopted.

[0039] (2). Specific structure of the caster As shown in FIG. 2, the caster 7 of the first embodiment includes a horizontal rotation shaft (support shaft) 22 rotatably held via a bearing (not shown) by a center support 15. Therefore, in the present embodiment, the support shaft portion is configured by the rotation shaft (support shaft) 22 independently of the ring body 16. The rotation shaft 22 protrudes from both the left and right sides of the center support 15, and the ring body 16 is fitted to the left and right protrusions in a non-removable and non-rotatable manner. The vertical shaft 17 is rotatably held by a thrust bearing portion 15a provided on the center support 15 so as to be offset in the front-rear direction from the rotation axis center of the ring body 16.

[0040] The ring body 16 has an inner ring portion 23 fitted to the rotation shaft 22 and an outer ring portion 24 integrally fixed to the inner ring portion 23. In the present embodiment, the outer ring portion 24 corresponds to the grounding portion. The inner ring portion 23 is an injection molded product made of a hard and tough synthetic resin such as nylon resin or polycarbonate. By forcibly fitting an inward annular protrusion 25 provided on the inner peripheral portion into an annular groove 26 provided on the rotation shaft 22, it is set to rotate integrally with the rotation shaft 22. Note that the inner ring portion 23 can be made of metal.

[0041] On the other hand, the outer ring portion 24 is made of a soft synthetic resin such as an elastomer, and includes a thin inner rim layer 27 that forms the inner peripheral portion and is fixed to the inner ring portion 23 by forced fitting or adhesion, a thin outer rim layer 28 that forms the outer peripheral portion and grounds on the floor surface F, and a compression deformation layer 29 disposed between the two layers.

[0042] The inner rim layer 27 and the outer rim layer 28 are formed with a high density that does not undergo compression deformation, and the outer surface is a smooth surface. The inner rim layer 27 can be deformed into a non-circular shape in an independent state, but when it is fitted to the hard inner ring portion 23 from the outside, it is held in a circular shape and its shape does not change. Therefore, the inner rim layer 27 can be fitted to the inner ring portion 23 in a non-detachable manner by utilizing its elasticity. Elongation Although it can be deformed into a non-circular shape in an independent state, when it is fitted to the hard inner ring portion 23 from the outside, it is held in a circular shape and its shape does not change. Therefore, the inner rim layer 27 can be fitted to the inner ring portion 23 in a non-detachable manner by utilizing its elasticity.

[0043] The outer rim layer 28 can be deformed into a non-circular shape when an external force is applied, while the compression deformation layer 29 can be crushed and deformed (compressed and deformed) by the total load of the chair's own weight and the external load (the weight of the person sitting). Therefore, as shown in FIGS. 2(C) and (D), due to the cooperative elastic deformation of the elongation deformation of the outer rim layer 28 and the crushing deformation of the compression deformation layer 29, the outer ring portion 24 can be crushed and deformed into a state of surface contact with a large area on the floor surface F. By deforming the lower surface into a flat surface in this way, the wheel body 16 is held non-rotatable, and the movement of the chair is suppressed.

[0044] The outer rim layer 28 and the compression deformation layer 29 are set to an elastic strength that does not deform under the weight of the chair itself but deforms when a user sits. Specifically, it is set not to deform under a load where the total load is less than 20 Kg, and to deform (start deforming and complete deformation) under a total load of about 20 to 60 Kg.

[0045] To describe more precisely, a swivel chair with one leg is supported by five casters 7, and since one caster 7 has two wheel bodies 16, a pair of outer rim layers 28 and compression deformation layers 29 are set to an elastic strength such that deformation starts and is completed under a load of 2 to 4 Kg. The relationship between the load and the amount of deformation from the start of deformation to the completion of deformation is defined as the elastic modulus, and that rate can be set arbitrarily.

[0046] In this way, when a person sits, the caster 7 deforms and is held non-rotatable, preventing the chair from moving randomly and ensuring the stability of the body. When the floor is made of a hard material such as flooring, a normal caster rotates particularly easily, and the chair may move following even a slight movement of the body. However, in this embodiment, even when the floor surface F is made of a wooden material like flooring, the chair can be stably held in a predetermined position. Therefore, it can contribute to creating an environment where one can concentrate on work.

[0047] Since the outer rim layer 28 is in surface contact with the floor surface F over a large area and the outer rim layer 28 has elasticity, there is also an advantage that damage can be prevented even when the floor surface F is made of flooring. Since the casters 7 are circular in the unloaded state, the ease of movement by pushing and pulling is not impaired. That is, the function of the casters 7 is maintained.

[0048] (3). Specific structure of the compression deformation layer An example of the specific structure of the outer ring portion 24 according to the first embodiment is shown in FIG. 3. That is, the entire outer ring portion 24 is made of an elastomer, and the compression deformation layer 29 has a three-dimensional lattice structure in which a large number of rod-shaped elements 30, 31, and 32 intersect. That is, in this example, it is composed of a group of first and second rod-shaped elements 30 and 31 that intersect each other when viewed in the direction of the rotation axis (X direction), and a group of third rod-shaped elements 32 that intersect the intersection of the first and second rod-shaped elements 30 and 31 and extend in the direction of the rotation axis. The rod-shaped elements 30, 31 are examples of the thin element bodies described in the claims.

[0049] In the schematic diagram of FIG. 3(C), each rod-shaped element 30, 31, 32 is shown in an orthogonal posture, but in reality, the crossing angle between the first rod-shaped element 30 and the second rod-shaped element 31 is not necessarily 90°. The first rod-shaped element 30 and the second rod-shaped element 31 do not pass through the rotation axis and are inclined in opposite directions with respect to the radiation passing through the rotation axis. For this reason, the first rod-shaped element 30 and the second rod-shaped element 31 do not undergo buckling deformation but undergo bending deformation even when a load is applied. However, since a large number of rod-shaped elements 30 to 31 restrict each other, it is possible to disperse the load while allowing appropriate deformation, thereby improving durability.

[0050] By tuning the thickness and arrangement density of each rod-shaped element 30 to 31, any elastic strength can be obtained. Therefore, it is also easy to prepare casters 7 for use in children's chairs or for use in high-functional swivel chairs with a large weight.

[0051] The outer ring portion 24 of this embodiment can be easily manufactured using a 3D printer. That is, since a 3D printer can perform three-dimensional molding while injecting material from a nozzle, it can be easily manufactured even for the compression deformation layer 29 into which a group of rod-shaped elements 30 to 31 with different postures three-dimensionally penetrate. Further, although the inner rim layer 27 and the outer rim layer 28 have a high density, the outer ring portion 24 composed of elements with different densities like this can also be easily manufactured by using a 3D printer.

[0052] The assembly of the caster 7 of this embodiment is performed by separately manufacturing the inner ring portion 23 and the outer ring portion 24 and then fitting them to form the wheel body 16, while attaching the rotary shaft 22 to the center support 15 and fitting the left and right wheel bodies 16 to the rotary shaft 22. It is also possible to manufacture the outer ring portion 24 while integrally molding the inner rim layer 27 onto the inner ring portion 23 with the inner ring portion 23 set in a jig. In this case, the assembly process of the inner ring portion 23 and the outer ring portion 24 becomes unnecessary. Further, since it is in the same state as insert molding or two-color molding, the fixing strength between the inner ring portion 23 and the outer ring portion 24 can also be maintained high.

[0053] In this embodiment of FIG. 3, the first rod-shaped element 30 and the second rod-shaped element 31 extend linearly, but it is also possible to bend one or both of them in an arc shape. In this case, either an inwardly bent posture or an outwardly bent posture can be adopted. Further, the first rod-shaped element 30 and the second rod-shaped element 31 can also change in thickness, for example, so that the cross-sectional area increases (or conversely) from the inner rim layer 27 toward the outer rim layer 28. Also, the cross-sectional shapes of the rod-shaped elements 30 to 31 can be selected from various shapes such as circular and angular.

[0054] In FIG. 3(B), the first rod-shaped element 30, the second rod-shaped element 31, and the third rod-shaped element 32 form a vertical and horizontal grid, but in the state of FIG. 3(B), it is also possible to form a diagonal grid by a group of rod-shaped elements with different inclined postures and form a ring-shaped rod-shaped element passing through the intersections.

[0055] Although the three-dimensional lattice structure that constitutes the compression deformation layer 29 is visible from the outside, since the caster 7 of such a lattice structure has not existed conventionally, it can attract people's attention as an extremely novel design.

[0056] (4). Another example of the outer ring part In the third embodiment shown in FIG. 4(A), the compression deformation layer 29 is composed of a group of fourth rod-shaped elements 33 extending in the radial direction, a group of fifth rod-shaped elements 34 extending in the circumferential direction and intersecting with the group of fourth rod-shaped elements 33, and a group of sixth rod-shaped elements 35 extending in the axial direction and intersecting with the intersection points of the groups of the fourth and fifth rod-shaped elements 33, 34. Therefore, also in this embodiment, the compression deformation layer 29 has a three-dimensional lattice structure. In any case, by changing the posture of the elements and the like, three-dimensional lattice structures in various forms can be obtained.

[0057] In FIGS. 4(B) to 5(A), the outer ring part 24 is manufactured by an injection molding method, and the compression deformation layer 29 has the same cross-sectional shape regardless of where it is cut. In the fourth embodiment shown in FIG. 4(B) among these, by forming a group of diamond-shaped and triangular through-holes 36, a group of plate-shaped elements 37 intersecting each other when viewed from the axial direction is arranged between the inner rim layer 27 and the outer rim layer 28. The plate-shaped element 37 is inclined with respect to the radiation passing through the rotation axis. Therefore, the compression deformation layer 29 has a kind of truss structure.

[0058] In this case, the thickness of the plate-shaped element 37 can be changed so that, for example, the thickness increases (or decreases) from the inner rim layer 27 toward the outer rim layer 28. Further, although the plate-shaped element 37 has a flat plate form, it can also be formed into a form warped (bent) inward or outward when viewed from the axial direction.

[0059] In the fifth embodiment shown in FIG. 4(C), the inner rim layer 27 and the outer rim layer 28 are connected by a group of plate-like elements 37 that alternately change their postures. Therefore, a group of triangular through-holes 36 are formed between the inner rim layer 27 and the outer rim layer 28 in a state where the shapes are alternately changed between a posture with the apex facing inward and a posture with the apex facing outward. In this case, the plate-like element 37 can be set to a shape that is bowed or bent when viewed in the direction of the rotation axis.

[0060] As shown in FIG. 5(A) First reference example In this case, by providing a large number of circular through-holes 36, the inner rim layer 27 and the outer rim layer 28 are connected by a group of curved plate-like elements 37. By varying the shape, size, and arrangement posture of the through-hole 36, compression deformation layers 29 in various forms (patterns) can be formed.

[0061] As schematically shown in FIG. 5(B) Second reference example In this case, the compression deformation layer 29 is made of a rubber material with a crosslinked structure or an elastic resin material with a foamed structure (for example, foamed urethane). The inner rim layer 27 and the outer rim layer 28 are formed separately from the compression deformation layer 29, but it is preferable that the compression deformation layer 29 is integrated with the inner rim layer 27 and the outer rim layer 28 by insert molding. Although the outer rim layer 28 needs to be deformed into a non-circular shape as its function, the inner rim layer 27 does not necessarily need to be deformed. It is also possible to eliminate the inner rim layer 27 and perform insert molding of the compression deformation layer 29 on the inner ring portion 23 and the outer rim layer 28.

[0062] In any case, the compression deformation layer 29 needs to be greatly crushed and deformed (compressed and deformed) so that the outer rim layer 28 makes surface contact with the floor surface F over a large area. It is also possible to form through-holes 36 as shown in FIGS. 4(B) to 5(A) while configuring the compression deformation layer 29 with an elastic material such as rubber or foamed urethane.

[0063] (5). Another exemplary form of the caster 7 As shown in FIG. 5(C) Sixth In the embodiment, the caster 39 has a spherical roller (ball body) 40 and a spherical receiver 41 that rotatably holds the spherical roller 40 in a non-removable manner. The spherical receiver 41 has a main body (support) 41a having a hemispherical concave surface that opens downward, and a retaining ring 41b fixed to the main body 41a from below, and a thrust bearing portion 41c is provided in the main body 41a.

[0064] The spherical roller (ball body) 40 is made of an elastic synthetic resin such as an elastomer or polyethylene, and is composed of a spherical inner housing 42, a spherical outer housing 43, and a compression deformation layer 44 of a three-dimensional lattice structure located between the two. The compression deformation layer 44 is a group of radial elements (Thin element body) 45 and a group of annular elements 46 that intersect with the group of radial elements 45. The group of annular elements 46 are located at a plurality of positions with different radii, and those having the same radius intersect to form a three-dimensional mesh structure (lattice structure).

[0065] As shown in FIG. 5(D) Seventh In the embodiment, the caster 47 includes a U-shaped main body (support) 48 having left and right side plates 48a, and one roller (wheel) 49 disposed between the left and right side plates 48a. The roller 49 is fixed to a rotating shaft 22 that is rotatably held by the left and right side plates 48a via bearings 50.

[0066] In this embodiment, the wheel body (roller) 16 is made of a resin having elasticity such as urethane resin, and is composed of an inner rim layer 27 fitted to the rotating shaft 22, an outer rim layer 28 that contacts the ground, and a compression deformation layer 29 of a three-dimensional lattice structure located between the two. The compression deformation layer 29 has the same structure as that shown in FIG. 4(A). As can be understood from this embodiment, the wheel body 16 does not necessarily have to be composed of an inner wheel portion 23 and an outer wheel portion 24.

[0067] It is also possible to form a wheel body 16 integrally with an outer cylinder that is fitted with a bearing on the outside with a support shaft portion as the central axis. That is, it is also possible to form the wheel body 16 while injecting molten resin particles into the outer cylinder using a 3D printer. In this case, after arranging the outer cylinder inside the main body 48, the wheel body 16 can be attached to the main body 48 by inserting a central axis through the outer cylinder.

[0068] As described above, embodiments of the invention according to the present application have been described, but the present disclosure can be embodied in various other ways. For example, the furniture to which it is applied is not limited to a chair, and can be applied to various things such as a table, a cart (wagon), and a product display stand. The caster does not necessarily have to be a horizontal swivel type, and the attachment means to the furniture does not necessarily have to be a vertical axis type.

Industrial Applicability

[0069] The invention according to the present disclosure can be embodied in a technique related to a caster for furniture. Therefore, it can be used industrially.

Explanation of Reference Numerals

[0070] 1 Seat 2 Backrest 3 Legs 6 Boss portion of the legs 7, 8, 39, 47 Casters 15 Center support 16 Wheel body 17 Vertical axis 22 Rotating shaft constituting the support shaft portion 23 Inner ring portion 24 Outer ring portion which is the grounding portion 27 Inner rim layer constituting the wheel body 28 Outer rim layer constituting the wheel body 29 Compression deformation layer 30 - 36 Rod - shaped elements constituting the three - dimensional lattice structure (Thin element body)

Claims

1. A caster disposed at the lower end of a furniture item, comprising: a support shaft portion rotatable about an axis in a horizontal posture, and a grounding portion disposed outside the outer periphery of the support shaft portion; The grounding portion is configured such that: when a load equal to or greater than a set value is applied, it is elastically deformable so as to be crushed to such an extent that rotation is suppressed, and as a structure that allows elastic deformation, it includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and coupling a large number of thin element bodies are three-dimensionally arranged and intertwined; A caster for furniture.

2. The grounding portion has a thin outer rim layer constituting its outer periphery and a thick compression deformation layer located inside the outer rim layer, and the compression deformation layer is constituted by the three-dimensional lattice structure; when a load equal to or greater than the set value is applied, the outer rim layer extends and deforms so as to be in surface contact with the floor surface, and the compression deformation layer is crushed and deformed in the vertical direction; The caster for furniture according to Claim 1.

3. The compression deformation layer includes a three-dimensional structure having a large number of independent spaces or recessed continuous spaces, and the three-dimensional structure is the three-dimensional lattice structure; The caster for furniture according to Claim 2.

4. A caster disposed at the lower end of a furniture item, comprising: a support shaft portion rotatable about an axis in a horizontal posture, and a grounding portion disposed outside the outer periphery of the support shaft portion; The grounding portion is configured such that: it has a thin outer rim layer constituting its outer periphery and a thick compression deformation layer located inside the outer rim layer; when a load equal to or greater than a set value is applied, the outer rim layer extends and deforms so as to be in surface contact with the floor surface, and the compression deformation layer is crushed and deformed in the vertical direction; the compression deformation layer includes a three-dimensional structure having a large number of independent spaces or recessed continuous spaces, and the three-dimensional structure includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and coupling a large number of thin element bodies are three-dimensionally arranged and intertwined; A caster for furniture.

5. The furniture item is a single-person chair, and is set to an elastic strength such that it is crushed and deformed to such an extent that rotation is suppressed by a total load of 20 kg or more and 60 kg or less including the self-weight of the chair; The caster for furniture according to any one of Claims 1 to 4.

6. A manufacturing method of a caster for furniture having a support shaft portion rotatable about an axis in a horizontal posture and a grounding portion disposed outside the outer periphery of the support shaft portion and being crushable and deformable, wherein the grounding portion is set to an elastic strength such that rotation is suppressed when a load equal to or greater than a set value is applied, The step of manufacturing the grounding portion; The step of attaching the grounding portion to the support; and has; The step of manufacturing the grounding portion is; processing of a compression deformation layer of a three-dimensional lattice structure, processing of an inner rim layer integrally continuous with the inner circumference of the compression deformation layer, and processing of the outer rim layer integrally continuous with the outer circumference of the compression deformation layer, and these processes are performed in a series using a 3D printer; The manufacturing method of the caster for furniture according to claim 4.

7. A caster disposed at the lower end of furniture, comprising: a spherical receiver opening downward, and a spherical roller rotatably held and non-removably covered from above by the spherical receiver and capable of elastic deformation; The spherical roller has a structure in which it elastically deforms so as to be crushed to such an extent that rotation is suppressed when a load equal to or greater than a set value is applied; As a structure that allows elastic deformation, it includes a three-dimensional lattice structure in which a large number of lattice bodies formed by crossing and joining a large number of thin element bodies are three-dimensionally arranged and intertwined; A caster for furniture.

8. A caster according to any one of claims 1 to 4, 7; legs supported on the floor via the caster; and furniture provided with the same.

9. A chair in which a caster according to any one of claims 1 to 4, 7 is attached to a leg supporting a seat. A chair.

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