JP2014043151A - Caster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new caster capable of demonstrating a suspension function by a configuration similar to a widespread caster.SOLUTION: A caster 1A of the present invention includes: a wheel 2A having a shaft hole 21; an elastic axle 3A which is inserted to the shaft hole 21 and is elastically deformable; a bearing part 4A which is formed or disposed inside the shaft hole 21, and whose center part 41 is projected to the side of the elastic axle 3A more than both ends 42 thereof; and a shaft support part 5A having two support holes 51 for supporting both end sides of the elastic axle 3A.

Description

  The present invention relates to a caster, and more particularly to a caster that can be suitably used for a luggage carrier such as a shopping cart, a carriage, or a construction unicycle.

  Generally, casters are used to carry luggage such as shopping carts, carts, and construction unicycles. Generally, casters that are widely used do not include a suspension device used in automobiles and the like. Therefore, an invention for adding a suspension function to a caster not provided with a suspension device has been conventionally made.

  As an example, a conventional caster has an axle support arm that is swingably mounted on a main frame, a wheel that is pivotally supported by the axle support arm, and a rod shape that is spanned between the main frame and the axle support arm. An elastic body (elastic wire) (Patent Document 1). This conventional caster alleviates the impact transmitted from the axle to the vehicle body by bending the rod-like elastic body in a curved shape.

JP 2008-94279 A

  However, since the conventional caster has an axle support arm, a rod-like elastic body, etc., the caster mechanism is complicated, the suspension function is inadequate, and the proportion of the commonly used caster parts is low. There was a problem.

  Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a new caster capable of exhibiting a suspension function with a configuration similar to a commonly used caster. .

  (1) In order to achieve the above-mentioned object, a caster according to the present invention supports a wheel having a shaft hole, an elastic axle inserted into the shaft hole and capable of elastic deformation, and both ends of the elastic axle. And a shaft support portion having a single support hole.

  Thus, the elastic axle is elastically deformed in accordance with the vertical movement of the wheel, so that the elastic axle serves as a suspension device. Therefore, even a caster in which the suspension device cannot be disposed independently can provide a suspension function to the caster.

  (2) Moreover, in the caster of the present invention, it is preferable that the elastic axle is constituted by a tension coil spring.

  As a result, when the wheel moves up and down, the elastic axle is elastically deformed while being pulled in the direction orthogonal to the axle direction, so that the deformation control of the elastic axle can be easily performed compared to the case where the elastic axle is a compression coil spring. Can do.

  (3) Further, in the caster according to the present invention, the elastic axle is formed in a cylindrical shape and is elastically deformable, and is elastically deformable that is included in the outer shaft and has a higher spring constant than the outer shaft. It is preferable to be constituted by a columnar or cylindrical inner shaft.

  By appropriately changing the inner diameter, length, and spring constant of the inner shaft, the spring constant of the entire elastic axle can be easily changed. Therefore, the elastic deformation of the elastic axle is suitable according to the load applied to the caster. Can be controlled.

  (4) Moreover, in the caster of the present invention, the inner shaft is preferably configured with an outer diameter smaller than the inner diameter of the outer shaft.

  Thereby, since the elastic deformation of the inner shaft can be started after the elastic deformation of the outer shaft is started, the elastic deformation of the elastic axle can be suitably controlled according to the load applied to the caster.

  (5) Moreover, in the caster of the present invention, the inner shaft is preferably shorter than the outer shaft, and has a length equal to or shorter than the length that can be supported by the shaft support portion.

  Thereby, since the elastic axle produces two-stage elastic deformation like a two-stage leaf spring, the elastic deformation of the elastic axle can be suitably controlled according to the load applied to the caster.

  (6) Moreover, it is preferable that the caster of this invention is provided or arrange | positioned inside the shaft hole, and is provided with the bearing part which the center part protrudes to the elastic axle side rather than the both ends.

  Thereby, when an elastic axle curves in the up-and-down direction, a bearing part can bend and deform elastic deformation of an elastic axle smoothly. In addition, since the contact area between the elastic axle that is elastically deformed and the bearing portion is increased, uneven wear of the elastic axle can be prevented.

  (7) Moreover, in the caster of the present invention, it is preferable that a cross section of a portion in contact with the elastic axle in the bearing portion is formed in a trapezoidal shape or a substantially semi-elliptical shape.

  Thereby, compared with the case of another shape, the contact area of the elastic axle which elastically deforms, and a bearing part becomes large, and the uneven wear of an elastic axle can be prevented.

  (8) Moreover, in the caster of the present invention, the bearing portion is preferably a bearing that can be inserted into the shaft hole.

  Thereby, since the friction between the elastic axle and the bearing portion is reduced, the durability of the elastic axle and the bearing portion can be improved. Further, when the bearing portion is worn, the bearing portion can be replaced.

  (9) Further, in the caster of the present invention, it is preferable that the two support holes are configured such that the inner diameters thereof are reduced in the direction from the inner side in the axial direction to the outer side in the axial direction of the elastic axle.

  As a result, compared to the case where the support hole is a cylindrical hole, when a load is applied to the wheel and the wheel moves in the vertical direction, the contact area of the support hole with the elastic axle increases, so the shaft support portion is elastic. It is possible to effectively prevent uneven wear and stress concentration on the elastic axles applied to the axles.

  (10) Further, in the caster according to the present invention, the wheel has an engagement recess that is recessed inside the wheel along the periphery of the shaft hole, and the shaft support portion is smaller than the inner diameter of the engagement recess. And it is preferable to have an engaging convex part protruding to the inside of the engaging concave part.

  Accordingly, when the elastic axle is unexpectedly dropped or damaged, the engagement concave portion and the engagement convex portion are engaged, and the wheel can be prevented from being removed from the shaft support portion.

  (11) Further, in the caster of the present invention, the engaging recess is configured by inserting a bearing portion shorter than the wheel shaft hole into the wheel shaft hole, and the shaft support portion includes the support hole and Two sleeves each having an engaging convex portion and two sleeves each having a head portion formed on the outer side in the axial direction of the elastic axle in the sleeve main body, and two sleeves each holding two sleeves on both ends of the elastic axle It is preferable to have a shaft support portion main body having a sleeve holding hole and two holders for holding both ends of an elastic axle extending from the sleeve outward in the axial direction.

  Thereby, the caster of this invention can be comprised using a wheel and shaft support part of a ready-made product.

  According to the caster of the present invention, since it has the above-described configuration, there is an effect that the suspension function is exhibited with a configuration similar to a commonly used caster.

FIG. 1 is a longitudinal sectional view showing a non-grounded state of wheels in a caster according to the first embodiment. FIG. 2 is a longitudinal sectional view showing a grounding state of a wheel in the caster according to the first embodiment. FIG. 3 is a longitudinal sectional view showing a non-grounded state of wheels in the caster according to the second embodiment. FIG. 4 is a partial cross-sectional view showing an elastic axle according to another embodiment similar to the second embodiment. FIG. 5 is a longitudinal sectional view showing a grounding state of a wheel in the caster according to the second embodiment.

  Hereinafter, the caster of the present invention will be described with reference to the two embodiments.

[Configuration of Casters of First Embodiment]
First, the caster of 1st Embodiment is demonstrated using FIG. FIG. 1 is a longitudinal sectional view showing a non-grounded state of wheels in a caster according to the first embodiment.

  The caster 1A of the first embodiment is used for a luggage carrier such as a shopping cart, a cart, and a construction unicycle. As shown in FIG. 1, the caster 1A includes a wheel 2A, an elastic axle 3A, a bearing portion 4A, and a shaft support portion 5A.

(Wheel 2A)
The wheel 2A may be an integral body of wheels and tires such as a shopping cart, or may be a separate body of wheels and tires such as a construction unicycle. The wheel 2A of the first embodiment is made of plastic, and the wheel and the tire are integrally formed. Further, the wheel 2A of the first embodiment has a shaft hole 21 at the center thereof.

  Moreover, it is preferable that the wheel 2A of the first embodiment has the engagement recess 22. The engaging recess 22 is configured to be recessed inside the wheel 2 </ b> A along the peripheral edges at both ends of the shaft hole 21.

(Elastic axle 3A)
The elastic axle 3A is inserted into the shaft hole 21 of the wheel 2A. The elastic axle 3A is an axle capable of generating a drag in a direction opposite to the applied direction while elastically deforming in the applied direction when a load is applied in a direction orthogonal to the axial direction. . The elastic axle 3A may be, for example, a highly rigid rubber shaft or a metal coil spring. The elastic axle 3A of the first embodiment is preferably a metal tension coil spring.

(Bearing part 4A)
The bearing portion 4 </ b> A is provided inside the shaft hole 21. 4 A of this bearing parts may be integrally formed with respect to the shaft hole 21, and may be arrange | positioned inside the shaft hole 21 by forming separately. The bearing portion 4 </ b> A of the first embodiment is a bearing that can be inserted into the shaft hole 21.

  Further, the central portion 41 of the bearing portion 4A protrudes inward (elastic axle 3A side) from both ends 42 thereof. Here, the cross-sectional shape of the portion in contact with the elastic axle 3A in the bearing portion 4A is preferably formed in a shape (for example, a substantially semi-elliptical shape or a trapezoidal shape) in which the central portion 41 of the bearing portion 4A protrudes inward. . The cross-sectional shape of the portion in contact with the elastic axle 3A in the bearing portion 4A of the first embodiment is substantially semi-elliptical.

(Shaft support 5A)
The shaft support 5A is formed of a metal flat plate or the like when the caster 1A is used for a shopping cart or the like, and is formed of a metal pipe or the like when the caster 1A is a construction unicycle. . The shaft support portion 5A has two support holes 51 on the extension line of the shaft hole 21 of the wheel 2A. These two support holes 51 support both end sides of the elastic axle 3 </ b> A inserted into the shaft hole 21. In addition, it is preferable that the two support holes 51 are configured such that the inner diameters thereof decrease in the direction from the inner side in the axial direction to the outer side in the axial direction of the elastic axle 3A.

  Further, the shaft support portion 5 </ b> A preferably has an engagement convex portion 52. The engaging convex portion 52 is smaller than the inner diameter of the engaging concave portion 22 provided in the wheel 2 </ b> A and protrudes to the inside of the engaging concave portion 22. The engaging convex part 52 may be formed integrally with the shaft support part 5A or may be formed separately.

[Effect of the caster 1A of the first embodiment]
Next, the effect of the caster 1A of the first embodiment will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing a grounding state of the wheel 2A in the caster 1A of the first embodiment.

  As shown in FIG. 2, when the wheel 2A of the caster 1A of the first embodiment is grounded, the load of a shopping cart or the like equipped with the caster 1A is transferred to the wheel via the shaft support portion 5A, the elastic axle 3A and the wheel 2A. 2A is applied to the grounded ground, and the reaction force of the load is applied to the wheel 2A from the ground.

  (1) Here, the caster 1A of the first embodiment includes a wheel 2A having a shaft hole 21, an elastic axle 3A that is inserted into the shaft hole 21 and can be elastically deformed, and both ends of the elastic axle 3A. A shaft support portion 5A having two support holes 51 to support.

  Accordingly, the elastic axle 3A is elastically deformed in accordance with the vertical movement of the wheel 2A, so that the elastic axle 3A serves as a suspension device. Therefore, even if the caster 1A cannot dispose the suspension device separately for reasons such as structure or arrangement, the suspension function can be imparted to the caster 1A.

  (2) Moreover, it is preferable that the elastic axle 3A is comprised by the tension coil spring.

  Thus, when the wheel 2A moves up and down, the elastic axle 3A is elastically deformed while being pulled in a direction orthogonal to the axle direction. This makes it easier to control deformation of the elastic axle 3A than when the elastic axle 3A is a compression coil spring.

  (6) Further, the caster 1A of the first embodiment is formed or arranged inside the shaft hole 21, and the center portion 41 includes a bearing portion 4A that protrudes toward the elastic axle 3A side from both ends 42 thereof. It is preferable to provide.

  Accordingly, when the elastic axle 3A is bent in the vertical direction, the bearing portion 4A can smoothly deform the elastic axle 3A. Further, since the contact area between the elastic axle 3A that is elastically deformed and the bearing portion 4A is increased, uneven wear of the elastic axle 3A can be prevented.

  (7) Moreover, it is preferable that the cross-sectional shape of the part which contact | connects the elastic axle 3A in the bearing part 4A is formed in the trapezoid or the substantially semi-elliptical shape.

  As a result, compared to other cross-sectional shapes other than trapezoidal or substantially semi-elliptical, the contact area between the elastic axle 3A that is elastically deformed while being curved in the vertical direction and the bearing portion 4A is increased, and the elastic axle 3A Uneven wear can be prevented.

  (8-1) The bearing portion 4A is preferably a bearing that can be inserted into the shaft hole 21.

  Thereby, the friction between the elastic axle 3A and the bearing portion 4A is reduced, so that the durability of the elastic axle 3A and the bearing portion 4A can be improved. Further, when the bearing portion 4A is worn, the bearing portion 4A can be replaced.

  (9) Further, the two support holes 51 in the shaft support portion 5A are configured such that the inner diameters of the support holes 51 become smaller in the direction from the inner side in the axial direction to the outer side in the axial direction of the elastic axle 3A. Is preferred.

  Thereby, compared with the case where the support hole 51 is a cylindrical hole, when a load is applied to the wheel 2A and the wheel 2A moves in the vertical direction, the contact area of the support hole 51 to the elastic axle 3A increases. It is possible to effectively prevent uneven wear and stress concentration of the elastic axle 3A that the shaft support 5A gives to the elastic axle 3A.

  (10) Moreover, it is preferable that the wheel 2A has the engagement recessed part 22 dented inside the wheel 2A along the peripheral edge of the shaft hole 21. And it is preferable that 5 A of shaft support parts have the engagement convex part 52 which is smaller than the internal diameter of the engagement recessed part 22, and protrudes to the inside of the engagement recessed part 22. FIG.

  As a result, when the elastic axle 3A is unexpectedly dropped or damaged, the engagement recess 22 and the engagement protrusion 52 engage with each other, so that the wheel 2A can be prevented from being removed from the shaft support portion 5A. it can.

[Configuration of Caster 1B of Second Embodiment]
Next, the caster 1B of 2nd Embodiment is demonstrated using FIG.3 and FIG.4. FIG. 3 is a longitudinal sectional view showing a non-grounded state of the wheel 2B in the caster 1B of the second embodiment. FIG. 4 is a partial cross-sectional view showing an elastic axle 3B according to another embodiment similar to the second embodiment.

  The caster 1B of 2nd Embodiment is provided with the wheel 2B, the elastic axle 3B, the bearing part 4B, and the shaft support part 5B, as shown in FIG. Hereinafter, differences from the first embodiment will be mainly described.

(Wheel 2B)
The wheel 2 </ b> B has a shaft hole 21 and an engagement recess 22. The engaging recess 22 is configured by inserting a bearing portion 4B shorter than the shaft hole 21 of the wheel 2B into the shaft hole 21. That is, the inner diameter of the engagement recess 22 is the same as the inner diameter of the shaft hole 21.

(Elastic wheel 2B)
The elastic axle 3 </ b> B has a multi-axis structure including an outer shaft 31 and an inner shaft 32. When a load is applied to the outer shaft 31 and the inner shaft 32 in a direction orthogonal to the axial direction, the outer shaft 31 and the inner shaft 32 can generate a drag in a direction opposite to the applied direction while elastically deforming in the applied direction. It is an axle. The outer shaft 31 and the inner shaft 32 may be, for example, high-rigidity rubber shafts or metal coil springs. The outer shaft 31 and the inner shaft 32 of the second embodiment are preferably metal tension coil springs.

  The outer shaft 31 is preferably formed in a cylindrical shape.

  The inner shaft 32 is included in the outer shaft 31. The inner shaft 32 is preferably formed in a columnar shape or a cylindrical shape. The inner shaft 32 is preferably configured with an outer diameter smaller than the inner diameter of the outer shaft 31.

  The spring constant of the inner shaft 32 is preferably set higher than the spring constant of the outer shaft 31.

  Further, the length of the inner shaft 32 may be equal to the length of the outer shaft 31 as shown in FIG. 4, or may be shorter than the length of the outer shaft 31 as shown in FIG. Good. The length of the inner shaft 32 of the second embodiment is shorter than the outer shaft 31 as shown in FIG. The length of the inner shaft 32 is set to a length equal to or shorter than the length that can be supported by the shaft support portion 5B.

(Bearing part 4B)
The bearing portion 4 </ b> B of the second embodiment is preferably a ball bearing that can be inserted into the shaft hole 21. Moreover, since the engagement recessed part 22 of 2nd Embodiment is comprised as mentioned above, it is preferable that the axial direction length of the bearing part 4B is formed shorter than the length of the axial hole 21 of the wheel 2B. . In this case, as in the first embodiment, the inner central portion 41 of the inner ring of the ball bearing protrudes inward (elastic axle 3B side) from the inner ends 42 thereof. The cross section of the inner ring of the ball bearing is preferably formed in, for example, a substantially semi-elliptical or trapezoidal shape. The cross-sectional shape of the portion in contact with the elastic axle 3B in the bearing portion 4B of the second embodiment is substantially semi-elliptical.

(Shaft support 5B)
The shaft support portion 5 </ b> B includes a shaft support portion main body 58, two sleeves 55, and two holders 57.

(Shaft support body 58)
The shaft support portion main body 58 has two sleeve holding holes 56. These two sleeve holding holes 56 hold the two sleeves 55 on both ends of the elastic axle 3B.

(Sleeve 55)
The two sleeves 55 have a sleeve main body 53 and a head 54.

  It is preferable that the sleeve main body 53 has the same support hole 51 and the engagement convex part 52 as 1st Embodiment. The sleeve body 53 is formed in a cylindrical shape having a length (height) longer than the length (depth) of the sleeve holding hole 56.

  The head 54 is formed in the sleeve main body 53 on the outer side in the axial direction of the elastic axle 3B. The outer diameter of the head 54 is formed larger than the inner diameter of the sleeve holding hole 56, and the head 54 is formed so as not to pass through the sleeve holding hole 56.

(Holder 57)
The two holders 57 hold both ends of the elastic axle 3 </ b> B extending from the sleeve 55 outward in the axial direction. When the elastic axle 3B is a coil spring, the holder 57 preferably has a female screw that engages with the coil spring.

[Effects of caster 1B of second embodiment]
Next, the effect of the caster 1B of the second embodiment will be described with reference to FIG. FIG. 5 is a longitudinal sectional view showing a grounding state of the wheel 2B in the caster 1B of the second embodiment.

  As shown in FIG. 5, when the wheel 2B of the caster 1B of the second embodiment is grounded, the load of a shopping cart or the like equipped with the caster 1B is transferred to the wheel via the shaft support 5B, the elastic axle 3B, and the wheel 2B. 2B is applied to the grounded ground, and the reaction force of the load is applied from the ground to the wheel 2B.

  (3) Therefore, the elastic axle 3 </ b> B is formed in a cylindrical shape and can be elastically deformed, and an elastically deformable columnar shape that is included in the outer shaft 31 and has a higher spring constant than the outer shaft 31. Or it is preferable to be comprised by the cylindrical internal shaft 32. FIG.

  By appropriately changing the inner diameter, length, and spring constant of the inner shaft 32, the spring constant of the entire elastic axle 3B can be easily changed, so that the elastic axle 3B can be changed according to the load applied to the caster 1B. Elastic deformation can be suitably controlled.

  (4) The inner shaft 32 is preferably configured with an outer diameter smaller than the inner diameter of the outer shaft 31.

  Thereby, when the outer shaft 31 is elastically deformed to a certain level or more, the inside of the outer shaft 31 comes into contact with the outside of the inner shaft 32, and the inner shaft 32 starts elastic deformation. That is, since the elastic deformation of the inner shaft 32 can be started after the elastic deformation of the outer shaft 31 is started, the elastic deformation of the elastic axle 3B can be suitably controlled according to the load applied to the caster 1B. .

  (5) Moreover, it is preferable that the inner shaft 32 is shorter than the outer shaft 31, and is comprised by the length below the length which can be supported by the shaft support part 5B.

  Thereby, when the outer shaft 31 is elastically deformed to a certain level or more, the inside of the outer shaft 31 comes into contact with the outside of the inner shaft 32, and the inner shaft 32 moves to the center of the outer shaft 31 while the inner shaft 32 is elastically deformed. To start. As a result, since the elastic axle 3B undergoes two-stage elastic deformation like a two-stage leaf spring, the elastic deformation of the elastic axle 3B can be suitably controlled according to the load applied to the caster 1B.

  (8-2) The bearing portion 4B of the second embodiment is preferably a ball bearing that can be inserted into the shaft hole 21.

  Thereby, since the friction between the elastic axle 3B and the bearing portion 4B is reduced, the durability of the elastic axle 3B and the bearing portion 4B can be improved.

  (11) Moreover, it is preferable that the engagement recessed part 22 is comprised by inserting the bearing part 4B shorter than the shaft hole 21 of the wheel 2B with respect to the shaft hole 21 of the wheel 2B. The shaft support portion 5B includes two sleeves 55 each having a sleeve main body 53 having a support hole 51 and an engaging convex portion 52, and a head portion 54 formed on the sleeve main body 53 on the outer side in the axial direction of the elastic axle 3B. A shaft support portion body 58 having two sleeve holding holes 56 for holding the two sleeves 55 on both ends of the elastic axle 3B, and both ends of the elastic axle 3B extending axially outward from the sleeve 55. It is preferable to have two holders 57 that hold the.

  Thereby, the conventional axle is changed to the elastic axle 3B with respect to the ready-made caster 1B, and the ready-made caster 1B is changed to the caster 1B of the second embodiment by adding the sleeve 55 and the holding tool 57. Can do. That is, the caster 1B of 2nd Embodiment can be comprised using the ready-made wheel 2B and the shaft support part 5B.

  That is, according to the caster of this embodiment, since it has the above-described configuration, the suspension function is exhibited with a configuration similar to a commonly used caster.

  In addition, this invention is not limited to embodiment mentioned above etc., A various change is possible as needed.

1A, 1B Caster 2A, 2B Wheel 3A, 3B Elastic axle 4A, 4B Bearing part 5A, 5B Shaft support part 21 Shaft hole 22 Engaging recess 31 Outer shaft 32 Inner shaft 41 Center part 42 End part (both ends)
51 Support Hole 52 Engaging Protrusion 53 Sleeve Body 54 Head 55 Sleeve 56 Sleeve Holding Hole 57 Holding Tool 58 Shaft Support Body

(1) In order to achieve the above-described object, a caster according to the present invention includes a wheel having a shaft hole, an elastic axle inserted into the shaft hole and configured by a metal coil spring and capable of elastic deformation, and elasticity. And a shaft support portion having two support holes for supporting both ends of the axle.

(1) Here, the caster 1A according to the first embodiment includes a wheel 2A having a shaft hole 21, and an elastic axle 3A that is inserted into the shaft hole 21 and is configured by a metal coil spring and capable of elastic deformation. And a shaft support portion 5A having two support holes 51 for supporting both ends of the elastic axle 3A.

(1) + (6) In order to achieve the above-described object, the caster according to the present invention is an elastic material that is elastically deformed by a wheel having a shaft hole and a metal coil spring inserted into the shaft hole. An axle, a shaft support portion having two support holes for supporting both end sides of the elastic axle, and a bearing formed or disposed inside the shaft hole, the center of which protrudes toward the elastic axle from the both ends And a section .

Thus, the elastic axle is elastically deformed in accordance with the vertical movement of the wheel, so that the elastic axle serves as a suspension device. Therefore, even a caster in which the suspension device cannot be disposed independently can provide a suspension function to the caster. Further, when the elastic axle is bent in the vertical direction, the bearing portion can smoothly bend and deform the elastic deformation of the elastic axle. Further, since the contact area between the elastic axle that is elastically deformed and the bearing portion is increased, uneven wear of the elastic axle can be prevented.

Claims (11)

A wheel having a shaft hole;
An elastic axle inserted into the shaft hole and capable of elastic deformation;
A shaft support portion having two support holes for supporting both ends of the elastic axle;
A caster characterized by comprising: The caster according to claim 1, wherein the elastic axle is constituted by a tension coil spring. The elastic axle is formed in a cylindrical shape and can be elastically deformed, and an elastically deformable cylindrical or cylindrical inner shaft that is included in the outer shaft and has a higher spring constant than the outer shaft. The caster according to claim 1, wherein the caster is configured as described above. The caster according to claim 3, wherein the inner shaft has an outer diameter smaller than an inner diameter of the outer shaft. The said inner shaft is shorter than the said outer shaft, Comprising: The length below the length which can be supported by the said shaft support part is comprised, The Claim 3 or Claim 4 characterized by the above-mentioned. Casters. A bearing portion that is formed or arranged inside the shaft hole, and whose central portion protrudes toward the elastic axle from its both ends,
The caster according to any one of claims 1 to 5, further comprising: The caster according to claim 6, wherein a cross section of a portion of the bearing portion in contact with the elastic axle is formed in a trapezoidal shape or a substantially semi-elliptical shape. The caster according to claim 6 or 7, wherein the bearing portion is a bearing that can be inserted into the shaft hole. The said two support holes are comprised so that an internal diameter may each become small in the direction which goes to an axial direction outer side from the axial direction inner side of the said elastic axle shaft, The any one of Claim 1-8 characterized by the above-mentioned. Casters according to item. The wheel has an engagement recess that is recessed inside the wheel along the periphery of the shaft hole,
The shaft support portion includes an engagement convex portion that is smaller than an inner diameter of the engagement concave portion and projects to the inside of the engagement concave portion. The caster according to item 1. The engagement recess is configured by inserting the bearing portion shorter than the wheel shaft hole into the wheel shaft hole,
The shaft support portion includes two sleeves each having a sleeve main body having the support hole and the engagement convex portion, and a head portion formed on the sleeve main body on the outer side in the axial direction of the elastic axle, and the elastic axle. A shaft support portion main body having two sleeve holding holes for holding the two sleeves on both ends of the sleeve, and two holdings for holding both ends of the elastic axle extending axially outward from the sleeve The caster according to claim 10, further comprising: a tool.

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