caster

Abstract

The present invention provides a caster in which the spring will not come off and the cushioning mechanism can be made into a simple structure. [Solution] The system comprises a pivot shaft 10 attached to a structure, an upper support part 20 to which the pivot shaft 10 is attached and which is configured to be rotatable relative to the structure, a wheel support part 30 attached to the upper support part 20 via a pivot point 24 and which extends in the front-rear direction and is pivotable in the up-down direction, a point of force application 31 of the wheel support part 30 located away from the pivot point 24 in the front-rear direction, a wheel 34 rotatably attached to the point of force application 31, a point of application 32 of the wheel support part 30 located away from the pivot point 24 and the point of force application 31 in the front-rear direction, an upper rod 43 extending from the upper support part 20 toward the point of application 32, a lower rod 46 adjacent to the upper rod 43 and extending from the point of application 32 toward the upper support part 20, and a buffer part 40 comprising an elastic body 47 installed around the upper rod 43 and the lower rod 46.

Description

Technical Field

[0001] The present invention relates to a caster provided on a structure such as a suitcase, and more particularly to a caster provided with a buffer portion for alleviating impacts caused by unevenness of a floor surface or a road surface.

Background Art

[0002] Conventionally, as disclosed in Japanese Utility Model Publication No. 59-19401 and Japanese Patent Application Laid-Open No. 2022-013209, casters provided with shock-absorbing members (buffer portions) have been disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the caster disclosed in Patent Document 1, the upper and lower ends of the spring are supported by uneven locking portions. With such a configuration, there is a risk that the spring may bend and come off from the locking portion.

[0005] Further, in the caster disclosed in Patent Document 2, although there is no risk that the spring comes off, regardless of whether the spring is disposed inside or outside the shaft, it is necessary to provide a precise shaft that can be expanded and contracted, and its configuration tends to be complicated.

[0006] The present invention has been made in view of the above points, and an object thereof is to provide a caster in which the spring does not come off and the buffer portion can have a simple configuration.

Means for Solving the Problems

[0007] The caster of the present invention is A pivot shaft attached to a structure, An upper support portion attached to the aforementioned pivot axis and configured to be rotatable relative to the aforementioned structure, A wheel support portion is attached to the upper support portion via a pivot point and is extendable in the front-rear direction while being able to swing in the up-down direction, Of the wheel support portion, the point of force application located at a position away from the pivot point in the front-rear direction, A wheel rotatably mounted on the aforementioned point of force application, Of the wheel support portion, the point of application of force is provided at a position located away from the fulcrum and the point of force application in the front-rear direction, A buffer comprising an upper rod extending from the upper support portion toward the point of application, a lower rod adjacent to the upper rod and extending from the point of application toward the upper support portion, and an elastic body installed around the upper rod and the lower rod, It is characterized by being equipped with [the following features].

[0008] According to the caster of this invention, the upper rod and the lower rod are adjacent to each other, so they function as a single rod. Therefore, the spring will not come off. Furthermore, since the upper rod and the lower rod are not fitted together, precision in dimensions is not required, and manufacturing is simple.

[0009] A preferred example of the caster of the present invention is: The sum of the length of the upper rod and the lower rod is configured to be longer than the length of the cushioning portion when it is fully extended. The lengths of the upper rod and the lower rod are configured to be shorter than the length of the buffer when it is most contracted.

[0010] In a preferred example of the caster of the present invention, the lengths of the upper and lower rods are appropriately set, so that no gap occurs in the longitudinal direction between the upper and lower rods even when the cushioning portion is extended. Furthermore, when the cushioning portion is retracted, the upper and lower rods do not obstruct the movement of the cushioning portion.

[0011] A preferred example of the caster of the present invention is: The upper rod is fixed to the upper support portion, and the lower rod is fixed to the wheel support portion.

[0012] In a preferred example of the caster of the present invention, it is not necessary to provide shafts or the like at the connection between the upper rod and the upper support, and at the connection between the lower rod and the wheel support, to allow the upper rod and the lower rod to rotate. Therefore, the structure of the caster can be made simpler.

[0013] A preferred example of the caster of the present invention is: The upper rod and the lower rod are configured to become thinner towards their tips.

[0014] According to a preferred example of the caster of the present invention, when the wheel support swings relative to the upper support about the pivot point, it is possible to reduce the contact between the upper rod and the lower rod that hinders the movement of the cushioning part.

[0015] A preferred example of the caster of the present invention is: The upper rod is positioned to either the left or right of the center of the buffer portion in the left-right direction. The lower rod is positioned to the left or right of the center of the buffer portion in the left-right direction.

[0016] A preferred example of the caster of the present invention is: The upper rod and the lower rod are positioned offset from each other in the front-rear direction of the buffer portion. The upper rod and the lower rod are positioned with a gap between them so that they do not come into contact with each other when the buffer is in operation.

[0017] According to these preferred examples of the caster of the present invention, when the wheel support swings relative to the upper support about the pivot point, the upper rod and the lower rod do not interfere with each other. [Effects of the Invention]

[0018] As described above, according to the caster of the present invention, the spring does not come off, and the buffer portion can have a simple configuration.

Brief Description of the Drawings

[0019] [Figure 1] It is a side view of a caster according to an embodiment of the present invention. [Figure 2] It is a front view of the caster. [Figure 3] It is a rear view of the caster. [Figure 4] It is a cross-sectional view taken along line A-A of FIG. 2. [Figure 5] It is a cross-sectional view taken along line B-B of FIG. 2. [Figure 6] It is a diagram for explaining the operation of the buffer portion. [Figure 7] It is a diagram for explaining another embodiment of the buffer portion. [Figure 8] It is a diagram for explaining another embodiment of the buffer portion.

Modes for Carrying Out the Invention

[0020] Hereinafter, an embodiment of the caster 1 according to the present invention will be described in detail with reference to the accompanying drawings.

[0021] As shown in FIGS. 1 to 5, the caster 1 of the present embodiment includes a swivel shaft 10, an upper support portion 20, a wheel support portion 30, a wheel 34, and a buffer portion 40. In FIGS. 2 and 3, the description of the elastic body 47 is omitted.

[0022] The swivel shaft 10 has its shaft positioned vertically and is attached to a structure (not shown). The swivel shaft 10 comprises an upper shaft portion 11, a flange portion 12, and a lower shaft portion 13. The upper shaft portion 11 is the part that protrudes upward from the upper support portion 20 and is machined to an appropriate shape depending on the type of structure to which it is attached. The flange portion 12 is provided in the middle of the shaft in the vertical direction and serves to transmit the weight of the structure to the upper support portion 20. The lower shaft portion 13 is the part that fits into the upper support portion 20 and has a notch 14 near its lower end. The structure refers to anything that is made movable by the caster 1 of this embodiment, and includes, for example, a suitcase, chair, desk, or a stand or shelf for placing objects.

[0023] The upper support portion 20 is substantially cylindrical in shape with an axis in the vertical direction and is rotatably attached to the structure via the pivot shaft 10. To enable rotation, the pivot shaft 10 may rotate relative to the structure, or the upper support portion 20 may rotate relative to the pivot shaft 10. The upper support portion 20 includes a vertical hole 21, a retaining portion 23, and a pivot point 24. The vertical hole 21 into which the pivot shaft 10 is inserted has a depth approximately equal to the length of the lower part of the shaft 13. A counterbore 22 is provided at the top of the vertical hole 21, and the flange portion 12 of the pivot shaft 10 abuts against the bottom surface of the counterbore 22. The retaining portion (pin) 23 is a horizontal pin 23 provided in the upper support portion 20. This pin 23 penetrates the upper support portion 20 and fits into a notch 14 in the lower part of the shaft 13, preventing the pivot shaft 10 from coming loose. The pivot point 24 supports the wheel support section 30 so that it can rotate relative to the upper support section 20, and is composed of a pivot shaft 25 provided in the horizontal direction. The pivot point 24 is located at the lower part of the upper support section 20. Furthermore, the area of ​​the upper support section 20 around the pivot point 24 is configured to have a narrow width w in the left-right direction (see Figure 2) so that the wheel support section 30 can be attached. In addition, the upper support section 20 is provided with an upper buffer section 41. The upper buffer section 41 will be described in detail in the description of the buffer section 40, which will be described later.

[0024] The wheel support section 30 is attached to the upper support section 20 via a pivot point 24 and extends in the front-rear direction while being able to swing up and down around the pivot point 24 as an axis. In side view, the wheel support section 30 is roughly J-shaped and includes a point of force application 31 and a point of application 32. The point of force application 31 is located on the wheel support section 30 at a position away from the pivot point 24 in the front-rear direction. In this embodiment, the point of force application 31 is located in the middle of the wheel support section 30 in the front-rear direction. In other words, the point of force application 31 is located behind the pivot point 24. An axle 33 is attached to this point of force application 31, and a rotatable wheel 34 is attached to the axle 33. The rotatable configuration of the wheel 34 may be such that the axle 33 rotates relative to the wheel support section 30, or the wheel 34 rotates relative to the axle 33. In this embodiment, a wheel support 30 is positioned in the center of the caster 1 in the left-right direction, with a pair of wheels 34 positioned on either side of it, but the number of wheels 34 is not limited to this. The point of application 32 is located within the wheel support 30, at a position away from the fulcrum 24 and the point of force application 31 in the front-rear direction. In this embodiment, the point of application 32 is located at the rear of the wheel support 30. That is, the point of application 32 is located behind the point of force application 31. A lower buffer 44 is also provided at the point of application 32. The lower buffer 44 will be described in detail in the description of the buffer 40, which will be described later.

[0025] The cushioning section 40 is provided between the upper support section 20 and the wheel support section 30 to mitigate impacts from the road surface or floor surface (hereinafter sometimes simply referred to as "road surface") transmitted through the wheel 34. The cushioning section 40 comprises an upper cushioning section 41, a lower cushioning section 44, and an elastic body 47. The upper cushioning section 41 constitutes the upper part of the cushioning section 40 and extends in an overhang shape from the middle of the upper support section 20 in the vertical direction toward the rear. The upper cushioning section 41 comprises a spring upper receiving surface 42 and an upper rod 43. The spring upper receiving surface 42 constitutes the lower surface of the upper cushioning section 41 and the upper end of the elastic body 47 abuts against it, and its surface is configured to be inclined toward the point of application 32 (lower cushioning section 44). The upper rod 43 is composed of a columnar or rod-shaped member and extends from the spring upper receiving surface 42 toward the point of application 32 (lower cushioning section 44). The upper rod 43 is fixed to the spring upper receiving surface 42, and no hinges or other shafts or members are required at the connection between the upper rod 43 and the spring upper receiving surface 42 to allow the upper rod 43 to swing. In this embodiment, the upper rod 43 has a roughly semicircular cross-section.

[0026] The lower buffer section 44 is provided at the point of application 32 of the wheel support section 30. The lower buffer section 44 comprises a spring lower receiving surface 45 and a lower rod 46. The spring lower receiving surface 45 constitutes the upper surface of the lower buffer section 44 and the lower end of the elastic body 47 abuts against it, and its surface is configured to be inclined toward the upper buffer section 41 (upper support section 20). The lower rod 46 is composed of a columnar or rod-shaped member and extends from the spring lower receiving surface 45 (point of application 32) toward the upper buffer section 41 (upper support section 20) while being adjacent to the upper rod 43. This lower rod 46 is fixed to the spring lower receiving surface 45, and no shafts or members such as hinges are required at the connection between the lower rod 46 and the spring lower receiving surface 45 to swing the lower rod 46. In this embodiment, the lower rod 46 has a substantially semicircular cross-section.

[0027] The elastic body 47 is installed around the upper rod 43 and the lower rod 46. For example, a cylindrical rubber or a coil spring 47 can be used as the elastic body 47. In this embodiment, a coil spring 47 is used. Both ends of this coil spring 47 are in contact with the upper spring receiving surface 42 and the lower spring receiving surface 45, supporting the wheel support section 30.

[0028] Next, the lengths of the upper rod 43 and the lower rod 46 will be explained with reference to the enlarged view of Figure 1. The sum of the length L1 of the upper rod 43 and the length L2 of the lower rod 46 is set to be longer than the length L3 of the cushioning section 40 when it is most extended, that is, the distance between the upper spring receiving surface 42 and the lower spring receiving surface 45. As a result, even when the cushioning section 40 is most extended, there is no gap in the longitudinal direction between the tip of the upper rod 43 and the tip of the lower rod 46, and the elastic body 47 does not come off. Furthermore, the lengths L1 and L2 of the upper rod 43 and the lower rod 46, respectively, are set to be shorter than the length of the cushioning section 40 when it is most contracted (not shown), that is, the distance between the upper spring receiving surface 42 and the lower spring receiving surface 45 when the elastic body 47 is most compressed. As a result, the phenomenon known as suspension bottoming out, in which the upper rod 43 comes into contact with the lower spring receiving surface 45 or the lower rod 46 comes into contact with the upper spring receiving surface 42, can be prevented.

[0029] Next, the positional relationship between the upper rod 43 and the lower rod 46 will be explained with reference to Figures 3 to 5. As shown in Figure 3, the upper rod 43 in this embodiment is positioned to one side (left or right) of the center c in the left-right direction of the buffer section 40 (wheel support section 30). The lower rod 46 is positioned to the other side (left or right) of the center c in the left-right direction of the buffer section 40 (wheel support section 30). Here, the upper rod 43 is positioned on the right side, and the lower rod 46 is positioned on the left side. Furthermore, the upper rod 43 and the lower rod 46 are in contact or close proximity in a slidable state where their movements are not hindered, and thus effectively function as a single rod. In this embodiment, the upper rod 43 and the lower rod 46 do not interfere with each other even when the wheel support section 30 swings. Therefore, as in the embodiment shown in Figure 8, it is not necessary to provide a relatively large gap s between the upper rod 43 and the lower rod 46. It should be noted that "slidable" means that there is preferably virtually no frictional resistance when the upper rod 43 and the lower rod 46 slide against each other.

[0030] Next, the operation of the wheel support section 30 and the buffer section 40 will be explained with reference to Figures 1, 3 to 6. Figure 6 shows the state in which the wheel support section 30 swings upward around the pivot point 24, as indicated by the horizontal line HL in Figures 4 and 6, and the buffer section 40 is compressed.

[0031] As shown in Figures 1 and 4, when no load is applied to the caster, the wheel support portion 30 is in its lowest swing position, and the cushioning portion 40 is in its most extended state. In this embodiment, the upper rod 43 and the lower rod 46 are arranged in a straight line.

[0032] Next, as shown in Figure 6 and the enlarged view of Figure 6, when a load is applied to the caster 1 due to unevenness in the road surface or the weight of a structure, the wheel support 30 swings upward and the buffer 40 compresses. As a result, the point of action 32 moves in an arc around the pivot point 24, so the upper rod 43 and the lower rod 46 are not in a straight line, but form a roughly V-shape or roughly X-shape in side view. At this time, as shown in Figure 3, the upper rod 43 and the lower rod 46 are arranged separately in the left-right direction of the buffer 40, so the upper rod 43 and the lower rod 46 do not interfere with each other and do not hinder the movement of the wheel support 30. If the wheel support 30 swings further upward from the state shown in the enlarged view of Figure 6 and the buffer 40 compresses, the degree to which the upper rod 43 and the lower rod 46 form a roughly V-shape or roughly X-shape in side view increases, and they may come into contact with the coil spring 47. Even in this case, since the coil spring 47 itself is flexible, it does not particularly hinder the movement of the wheel support section 30 and the cushioning section 40.

[0033] Next, with reference to Figure 7, a caster 101 having another embodiment of the upper rod 143 and lower rod 146 will be described. In this embodiment, the upper rod 143 (dashed line) and the lower rod 146 are configured to become thinner towards their ends. This prevents contact between the upper rod 143 and the lower rod 146 and the coil spring 47 when the cushioning portion 40 is compressed, and enables smoother movement of the cushioning portion 40.

[0034] Next, with reference to Figure 8, a caster 201 having another embodiment of the upper rod 243 and lower rod 246 will be described. In this embodiment, the upper rod 243 and lower rod 246 are offset in the front-rear direction of the caster 1 (cushioning part 40). In this case, it is preferable to avoid contact between the upper rod 243 and the lower rod 246 when the wheel support part 30 swings and the point of action 32 moves in an arc around the pivot point 24. For this reason, a gap s is provided between the upper rod 243 and the lower rod 246.

[0035] As explained above, in this embodiment of the caster, the upper rod and the lower rod form a pseudo-single rod, so the elastic body does not fall off. Furthermore, the upper rod and the lower rod are positioned so as not to interfere with each other's movement. For this reason, compared to a configuration such as one in which a piston (inner cylinder) is placed inside a cylinder (outer cylinder), dimensional precision is not required, and the number of parts can be reduced. Moreover, in a configuration where the upper rod and the lower rod are installed separately in the left and right directions of the buffer section, they appear as if they were a single rod, thus not detracting from the aesthetics.

[0036] Furthermore, the upper rod is fixed to the upper spring support surface, and the lower rod is fixed to the lower spring support surface. Therefore, there is no need to add a rotatable structure to the base of the upper and lower rods, and it is possible to manufacture the upper rod and upper support part, and the lower rod and wheel support part as a single unit. This also reduces the number of parts. In addition, the number of sliding parts such as cylinders, pistons, and hinges can be reduced, thereby reducing frictional resistance and enabling smooth operation of the wheel support part and cushioning part. As a result, it is possible to manufacture casters with high-performance cushioning parts while simplifying the manufacturing process. [Explanation of symbols]

[0037] 1,101,201...caster, 10...Swivel axis, 11...Upper part of axis, 12...Flange part, 13...Lower part of axis, 14...Notch, 20... Upper support part, 21... Vertical hole, 22... Counterbore, 23... Retaining part (pin), 24... Pivot point, 25... Pivot point shaft, 30...Wheel support, 31...Point of effort, 32...Point of application of force, 33...Axle, 34...Wheel 40...cushion section, 41...upper cushion section, 42...upper spring receiving surface, 43, 143, 243...upper rod, 44...lower cushion section, 45...lower spring receiving surface, 46, 146, 246...lower rod, 47...elastic body (coil spring), L1, L2, L3... length, s... gap, w... width,

Claims

1. A pivot shaft attached to a structure, An upper support portion attached to the aforementioned pivot axis and configured to be rotatable relative to the aforementioned structure, A wheel support portion is attached to the upper support portion via a pivot point and is extendable in the front-rear direction while being able to swing in the up-down direction, Of the wheel support portion, the point of force application located at a position away from the pivot point in the front-rear direction, A wheel rotatably mounted on the aforementioned point of force application, Of the wheel support portion, the point of application of force is provided at a position located away from the fulcrum and the point of force application in the front-rear direction, A buffer comprising an upper rod extending from the upper support portion toward the point of application, a lower rod adjacent to the upper rod and extending from the point of application toward the upper support portion, and an elastic body installed around the upper rod and the lower rod, A caster characterized by having the following features.

2. The sum of the length of the upper rod and the lower rod is longer than the length of the cushioning portion when it is fully extended. The caster according to claim 1, wherein the lengths of the upper rod and the lower rod are each shorter than the length of the cushioning portion when it is most retracted.

3. The caster according to claim 1, wherein the upper rod is fixed to the upper support portion and the lower rod is fixed to the wheel support portion.

4. The caster according to claim 1, wherein the upper rod and the lower rod are configured to become thinner towards their tips.

5. The upper rod is positioned to either the left or right of the center of the buffer portion in the left-right direction. The caster according to any one of claims 1 to 4, wherein the lower rod is positioned to the left or right of the center of the buffer portion in the left-right direction.

6. The upper rod and the lower rod are positioned offset from each other in the front-rear direction of the buffer portion. The caster according to any one of claims 1 to 4, wherein a gap is provided between the upper rod and the lower rod so that they do not come into contact with each other when the cushioning portion is in operation.

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