阅读说明：本技术 用于行李物品的滚轮组件 (Roller assembly for luggage ) 是由 保罗·古拉贾尼 于 2019-02-06 设计创作，主要内容包括：本申请的实施例涉及一种用于行李物品的滚轮组件(104),行李物品例如可以是行李箱(100)。滚轮组件(104)包括：中心支撑元件(200)；第一滚轮(132),可转动地连接到中心支撑元件(200)上；第二滚轮(134),可转动地连接到所述中心支撑元件(200)上,且所述第二滚轮(134)位于与第一滚轮(132)相对的一侧上,其中,第一滚轮(132)和第二滚轮(134)具有共同的旋转轴X；其中,第一滚轮(132)和第二滚轮(134)均为半球形。(Embodiments of the present application relate to a scroll wheel assembly (104) for an item of luggage, such as a luggage case (100). The scroll wheel assembly (104) includes: a central support element (200); a first roller (132) rotatably connected to the central support element (200); a second roller (134) rotatably connected to the central support element (200), the second roller (134) being located on a side opposite to the first roller (132), wherein the first roller (132) and the second roller (134) have a common rotation axis X; wherein, the first roller (132) and the second roller (134) are both hemispherical.)

1. A roller assembly for an item of luggage, the roller assembly comprising:

a center support member;

a first roller rotatably connected to the center support member;

a second roller rotatably connected to the center support member, the second roller being located on a side opposite to the first roller;

wherein the first roller and the second roller have a common rotation axis, and the first roller and the second roller are both hemispherical.

2. The roller assembly of claim 1 wherein the first roller and the second roller each include an inner core and an outer tire casing capable of receiving at least a portion of the inner core.

3. The roller assembly of claim 2 wherein the outer tire is frusto-hemispherical in shape.

4. The roller assembly of claim 2 or 3 wherein the outer tire casing includes an outer surface, at least a portion of which is three-dimensionally curved.

5. The roller assembly of claim 4 wherein the curvature radius of the curvature of the outer surface is 0.03mm^-1～0.05mm^-1。

6. The roller assembly of claim 4 or 5 wherein the outer surface includes a flat portion having a predetermined width and a fixed radius.

7. The roller assembly of claim 6 wherein the predetermined width is 3mm to 15 mm.

8. The roller assembly of claim 6 or 7, wherein the fixed radius is 20mm to 30 mm.

9. The roller assembly of any one of claims 2-8 wherein the outer tire includes a cavity defined by an inner surface, the inner surface including at least two radial grooves.

10. The roller assembly of any one of claims 2-9 wherein the inner core is frusto-hemispherical.

11. The roller assembly of claim 10 wherein the inner core includes an outer surface that is capable of mating with an inner surface of the outer tire casing.

12. The roller assembly of claim 11 wherein the outer surface includes at least two radial ribs.

13. The roller assembly of any one of claims 2-12 wherein the inner core includes a socket adapted to rotatably connect the roller to the center support member.

14. The roller assembly of any one of claims 1-13 wherein the center support member includes a main body portion and a connecting portion, the main body portion being disposed between the first roller and the second roller to connect the first roller and the second roller together; wherein the connecting portion is capable of connecting the wheel assembly to the luggage case.

15. The roller assembly of claim 14 wherein the body portion is flat.

16. The roller assembly of claim 14 or 15 wherein the body portion is cylindrical in shape, the cylindrical shape having a truncated portion.

17. The roller assembly of any one of claims 14-16 wherein the center support member includes a first mechanical fastener disposed along a central axis of the body portion, and wherein the first roller and the second roller are each rotatably connected to the center support member by the first mechanical fastener, the central axis of the body portion being aligned with the common axis of rotation.

18. The roller assembly of any one of claims 14-17 wherein the central support element includes at least two radial spokes.

19. The roller assembly of any one of claims 1-18 including a wheel housing, the center support member being rotatably connected to the wheel housing, and the wheel housing being connectable to a luggage case.

20. The roller assembly of any one of claims 1-19 wherein the first roller and the second roller each comprise a thermoplastic elastomer material.

21. The roller assembly of any one of claims 2-20 wherein the inner core includes a polypropylene material and the outer tire casing includes a thermoplastic elastomer material.

22. The roller assembly of any one of claims 1-21 wherein the center support member includes a nylon material.

23. An article of luggage comprising the roller assembly of any one of claims 1-22 and further comprising a hand-pull handle assembly and at least one carry handle.

Technical Field

The invention relates to a roller wheel assembly for luggage.

Background

Generally, an item of luggage may include a wide variety of devices that may be used to store, carry, and/or transport the device or item. For example, a luggage item may be a type of luggage item that may be used to store items of a user for convenient storage and transportation. Luggage cases are often equipped with wheels, towing handles, and openings to allow access to the interior of the luggage case.

There are a wide variety of wheels or casters for trolley luggage that enable the luggage to be pushed along the ground by a user to travel. Typically, two, four or eight rollers are provided at the bottom corners of the luggage case to provide a stable base. In order to allow the luggage case to easily travel along the ground and maintain balance when pulled or pushed, it is important to arrange the wheels on a horizontal surface. This is particularly true for luggage cases having four-wheel or eight-wheel configurations. I.e. pushing or pulling the luggage case with the luggage case upright and all wheels in contact with the ground.

Typically, the roller may be provided as part of a roller assembly having a plurality of components including, for example, a wheel housing, a wheel fork, and a roller body. The rollers may take a generally cylindrical shape, for example, a radial disc shape. Typically, such a roller may be provided with a single angle of rotation (i.e. the roller may rotate about its axis of rotation, but may also be fixed in and rotate along a plane) or two angles of rotation, such that the roller may rotate about its axis of rotation, and may also rotate about a second axis of rotation orthogonal to the aforementioned axis of rotation (the first axis of rotation). The second axis of rotation allows the luggage case to be easily maneuvered in any direction along the ground without the need to turn the entire luggage case. A wheel assembly having a single turning angle is generally used for a luggage case equipped with two wheels. Wheel assemblies having two angles of rotation are more commonly provided on luggage cases having four or eight wheels to enable such luggage cases to easily slide in any direction along the ground with all wheels in contact with the ground.

Of course, it is necessary to expose the rollers of the luggage case to the ground (e.g., to protrude outward from the main body of the luggage case), but such exposure has the inherent problem that the rollers are susceptible to damage, particularly during transportation, from side impact and "bumping" against foreign objects. Such an impact may damage the roller assembly such that the second axis of rotation is no longer parallel to the vertical plane. This, in turn, may result in the wheels no longer being aligned in the same horizontal plane as the other wheels of the luggage, thereby resulting in the luggage being likely to be out of balance when upright. In turn, this can result in the luggage case being prone to tipping and tipping, making it difficult to place (i.e., without user assistance) upright and move.

Conventional roller assemblies having "external" bifurcated clamps (i.e., clamps having two arms for gripping both sides of the roller) may mitigate some of the risk of impact damage by acting as a shroud or barrier to the roller. However, this protects only a small portion of the roller, the remaining majority of the roller remaining exposed.

In addition to being hit by external objects, the wheels of the case must be able to withstand without damage when the case falls from a height to the floor. In particular, luggage cases are often subjected to rigorous testing during production, commonly referred to as "drop tests," even if the loaded luggage items (i.e., having a predetermined weight) are intentionally dropped from several predetermined heights and the wheels fall to the ground. Testing can be performed to ensure that the rollers can withstand such falls without damage, or to ensure that the rollers can withstand damage that may affect the performance of the luggage article. In this regard, the truck assemblies are typically made of a strong/rigid material that can withstand such impacts.

However, although the rigid roller can withstand the impact of the drop test, as a result of using the rigid roller, most of the impact is absorbed by the trunk body and the articles contained therein. This may cause mechanical or physical impact to the articles in the luggage.

The above-described conventional bifurcated clamp roller assembly exacerbates this problem by limiting the ability of the roller to withstand elastic deformation due to the clamping force, thereby reducing any damping effect that the roller may provide.

Accordingly, there is a need for an improved truck assembly configuration that better mitigates the risk of impact damage and vibration.

Disclosure of Invention

According to one aspect of the present application, a roller assembly for an item of luggage is provided. The roller assembly includes a center support member, a first roller rotatably connected to the center support member, and a second roller rotatably connected to the center support member on an opposite side of the first roller. The first roller and the second roller have a common axis of rotation. The first roller and the second roller are each substantially hemispherical.

The hemispherical shape of the rollers serves to deflect an impact from an external object, for example, during transport of an item of luggage to which the roller assembly is mounted. This is because the curved outer surface acts to deflect forces from external objects. This reduces the impact force to which the roller assembly is subjected, thus reducing the risk of direct damage to the roller assembly and indirect damage to any associated items. For example, for an eight-wheeled item of luggage, the risk of one of the scroll wheel assemblies accidentally deviating from its X-or Y-axis (i.e., the angle corresponding to the two orthogonal axes of rotation) is reduced, thereby reducing the likelihood of the scroll wheel assembly being dislodged from alignment with the other scroll wheel assembly. This in turn reduces the likelihood of the luggage item tipping over, and also reduces the likelihood of failure of the roller assemblies during movement of the luggage item (which can cause drag on the luggage item and reduce the ability of the luggage item to move normally).

The use of a central support element to connect the rollers means that the rollers can be in a suitably parallel position along a common axis of rotation and be integral with the central support element (i.e. adjacent to each other) without the need for any complex structure such as a conventional double fork clamp. In addition to integrating the rollers together in the correct parallel arrangement, the central support element also means that if the roller assembly is to be dropped from a height and the rollers land, the rollers are not hindered by elastic deformation and expansion (particularly in the lateral direction), unlike conventional roller assemblies having a two-pronged clamp configuration.

As mentioned above, the use of a central support element leaves the elastic deformation of the roller unhindered. In addition, the semi-spherical shape of the roller means that the contact area between the roller and the impact surface (e.g., the ground) will increase due to elastic deformation, as compared to a conventional cylindrical roller. Thus, the roller can more effectively transmit kinetic energy from the roller assembly, thereby attenuating vibration to which the roller assembly is subjected upon impact and reducing the impact force to which the roller assembly is subjected. This, in turn, reduces the likelihood of damage to the roller assembly, as well as the likelihood of impacts that may be experienced by the associated and/or contents thereof.

The first and second rollers may each include an inner core and an outer tire. The outer tyre may house at least part of the inner core. The outer tyre may be generally frusto-hemispherical in shape. The outer tyre may comprise an outer surface, at least a portion of which is three-dimensionally curved. The curvature radius of the curved portion of the outer surface may be 0.03mm^-1～0.05mm^-1. The outer surface may include a flat portion having a predetermined width and a fixed radius measured from the rotational axis. The preset width may be 3mm to 15 mm. The fixed radius may be 20mm to 30 mm. The outer tire may include a cavity defined by an inner surface including at least two radial grooves.

As mentioned above, the hemispherical shape and associated curvature provides at least: (i) impact deflection capability; (ii) the ability to efficiently transfer kinetic energy from a drop impact to the impact surface due to elastic deformation. The flat portion of the outer surface may provide a larger tread for the roller assembly to increase friction and traction to enable the roller assembly to grip the surface on which it is resting or traveling.

The inner core may be substantially frusto-hemispherical in shape. The inner core may comprise an outer surface capable of mating with the inner surface of the outer tyre. The outer surface may include at least two radial ribs.

Since the inner core matches the inner dimensions of the outer tyre, there is a tight fit between the two components, limiting relative movement. The radial ribs of the inner core may be adapted to snap into the radial grooves of the outer tyre, which further limits the relative movement (particularly the relative rotational movement) between the inner core and the outer tyre. This means that energy can be saved during the travel of the roller assembly.

The inner core may include a socket capable of rotatably connecting the roller to the central support member.

The core backing component may include a body portion and a connecting portion. The body portion may be disposed between the first roller and the second roller to connect the first roller and the second roller together. The attachment portion may attach the truck assembly to an item of luggage. The body portion may be substantially flat. The body portion may be substantially cylindrical, the cylinder having a truncated portion. The truncated portion may be at the bottom of the main body portion and thus may be a particularly useful feature when the luggage item with the wheel assembly is moved along an uneven surface. This is because it reduces the likelihood that the core backing component will "ride" against the uneven surface and create frictional drag.

The central support element may comprise a first mechanical fastener disposed along a central axis of the body portion. Both the first roller and the second roller may be rotatably coupled to the center support member by a first mechanical fastener. In this regard, the roller cannot be directly supported by any other structural element, such as a clamp arm used in conventional bifurcating roller assemblies. Therefore, the lateral expansion (i.e., elastic deformation) of the roller is not restricted. The central axis may be aligned with a common axis of rotation.

The central support element comprises at least two radial spokes. In addition to reducing the material required to manufacture the center support element, the radial spokes may also include biasing springs that enable the mechanical fasteners to be held in place, but also allow a degree of deflection such that any impact on the roller assembly is reduced.

The roller assembly may include a wheel housing. The center support member may be rotatably connected to the wheel housing, and the wheel housing may be connectable to an item of luggage.

The first roller and the second roller may comprise a thermoplastic elastomer (TPE) material. Thermoplastic elastomers, such as materials composed of polymer blends (e.g., plastics and rubbers), may have both thermoplastic and elastomeric properties. Furthermore, the shape of the thermoplastic elastomer can be easily manufactured by injection molding. The elastic properties mean that the material can undergo a temporary elastic deformation, thereby cushioning and reducing impact. The thermoplastic elastomer material may also have a specific stiffness which imparts stiffness to the rollers to achieve traction and provide wear resistance in the absence of sudden impact forces. In addition, the thermoplastic elastomer has shock absorbing properties, and thus may provide additional damping to vibrations, thereby further reducing vibrations from the shock. A hemispherical roller means that more thermoplastic elastomer can be provided than other conventional roller shapes, such as cylindrical or star-shaped rollers, so that the vibrations caused by the impact can be further reduced. For example, the thermoplastic elastomer may be a Thermoplastic Polyurethane (TPU) having a hardness value of 70A to 100A.

The inner core may comprise a polypropylene material. The polypropylene provides rigidity to the roller assembly to maintain the shape of the roller. Polypropylene also has a degree of flexibility which reduces the likelihood of breakage from impact. This flexibility means that the inner core can also absorb vibrations from the impact and provide a further damping effect.

The outer tyre may comprise a thermoplastic elastomer material. As described above, the thermoplastic elastomer has an impact absorbing property, and can be temporarily elastically deformed at the time of impact. In addition, thermoplastic elastomer materials are relatively soft compared to other conventional materials used in luggage article rollers (e.g., polypropylene and nylon). The softness of the thermoplastic elastomer used in the tire can have a vibration damping effect, thereby reducing noise when the roller travels along a surface.

The core backing component may comprise a nylon material. The nylon material is rigid and therefore the rollers may be arranged to be fixed relative to the main body of the luggage item. Nylon is also self-lubricating, whereby the roller can move more smoothly (i.e., less frictional resistance between the core backing component and the roller).

According to another aspect of the present application, there is provided an item of luggage comprising at least one roller assembly, and further comprising: a hand-pull handle assembly and at least one handle. The luggage item may be a luggage case.

Drawings

Embodiments of the present application will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1A is an isometric view of a luggage case having wheels according to an embodiment of the present application;

FIG. 1B is a bottom schematic view of the luggage case of FIG. 1A;

FIG. 2A is an isometric view of the wheels of FIG. 1A for the luggage case;

FIG. 2B is a side view of the wheels for the luggage of FIG. 1A;

FIG. 2C is a front view of the wheels for the luggage of FIG. 1A;

FIG. 3 is an exploded view of the rollers of FIG. 1A for the luggage case;

FIG. 4A is a schematic view of the ball of the roller of the present application in contact with the ground; and

fig. 4B is a schematic illustration of the ball of fig. 4A undergoing temporary elastic deformation.

Detailed Description

Embodiments of the present application relate generally to a roller assembly for an item of luggage configured with a double hemispherical roller for mitigating impact damage to the roller and any associated luggage items during transportation.

Embodiments of the invention are described herein with reference to luggage, which is generally understood to be an item of luggage for containing and transporting items of a person. It should be understood, however, that the inventive concept may be applied to any luggage article and is not limited to use with luggage only. For example, the roller assemblies may be used with wheeled bags, wheeled luggage items, wheeled backpacks, and the like. Furthermore, it is envisaged that the inventive concept may be used outside the field of luggage items for any device operated by an operator using rollers, such as furniture, trolleys and the like. The luggage case described herein is a so-called "soft" luggage case because the luggage body comprises a non-molded material, in this case a fabric material. However, it will be appreciated that other types of luggage may be used, for example "hard" luggage comprising any moulded material, plastics material or metal/metal alloy material.

Fig. 1A is a front view of the soft luggage 100. The luggage 100 includes a main body 102 of the luggage, at least two roller assemblies 104, a side handle 106, a top handle 108, a retractable hand grip 110, a cover 112, a first zipper arrangement 114 for enabling the cover 112 to be opened and closed, a closable front pocket 116, and a second zipper arrangement 118 for enabling the front pocket 116 to be opened and closed.

The main body 102 of the luggage case is "box" shaped, generally parallelepiped in shape, having a cavity bounded by six major exterior surfaces (a front 120, a back 122, a first side 124, a second side 126, a top 128, and a bottom 130). In this embodiment, at least two of the roller assemblies 104 are disposed at four corners on the bottom surface 130 of the luggage case, the side handles 106 are disposed on the first side surface 124, and the top handle 108 is disposed on the top surface 128. A retractable, hand-pull handle 110 disposed on the top surface 128 extends parallel to the back surface 122 and across the top surface 128, and both the cover 112 and the front pocket 116 are disposed on the front surface 120. The cover 112 is attached to the second side 126 along at least a portion of one edge to form a hinge. First zipper arrangement 114 extends around the perimeter of cover 112 and around the perimeter bounded by first side 124, second side 126, top 128, and bottom 130 (but not rear 122). When the first zipper arrangement 114 is in the closed state, the cover 112 is securely attached to the remainder of the main body 102 of the luggage case such that the luggage case is closed and any objects therein cannot be accessed. When the first zipper arrangement 114 is in the open state, the luggage case 100 is opened such that any objects contained therein may be accessed.

Fig. 1B is a bottom view of the luggage 100 and illustrates the bottom surface 130 provided with at least two roller assemblies 104. In this embodiment, the luggage 100 is an eight-wheel configuration having four roller assemblies 104, each roller assembly 104 including two rollers in a pair. In particular, four roller assemblies 104 are disposed at the four corner ends of the bottom surface 130. The four roller assemblies 104 are of similar size and construction. This arrangement provides strong lateral stability, ensuring that the luggage 100 can be placed upright (i.e., all wheels in contact with the ground) without any external supporting force. The roller assemblies 104 are aligned in a plane such that when the luggage case 100 is upright on a horizontal plane, the top and bottom surfaces 128, 130 are parallel to the horizontal plane and the remaining surfaces are substantially perpendicular to the horizontal plane. This means that the center of gravity of the luggage piece 100 may be as centered as possible with respect to the bottom surface 130, further improving the stability of the luggage piece 100 and reducing the likelihood of tipping.

Fig. 2A-2C illustrate the truck assembly 104 of a single luggage case in more detail when assembled.

Fig. 3 is an exploded view of the truck assembly 104 of a single luggage case, showing its components prior to assembly.

The truck assembly 104 in fig. 2A, 2B, 2C, and 3 is shown separately from the luggage 100, but is depicted as being upright as if the truck assembly 104 were connected to the luggage 100 and the luggage 100 were placed vertically on the truck assembly 104 in contact with the ground.

Referring to FIG. 2A, an isometric view of the scroll wheel assembly 104 is shown. The roller assembly 104 includes a first roller 132, a second roller 134, a center support member 200, and a wheel housing 300. The first and second rollers 132,134 are arranged parallel to the central support element 200 and along a common rotation axis X. The first and second rollers 132 and 134 are identical in shape and size. The center support member 200 may sometimes be referred to as a "fork," but it should be understood that the center support member 200 of embodiments of the present application is not forked in that it does not have two arms/protruding stems. The core backing component 200 includes a body portion 202 and a connecting portion 204. The first and second rollers 132 and 134 are coupled to the body portion 202. The center support member 200 is connected to the wheel housing 300 by a connecting portion 204. The scroll wheel assembly 104 is connected to the main body 102 of the luggage case through the wheel housing 300.

The first and second rollers 132,134 are both substantially hemispherical in shape and are arranged in parallel on either side of the central support element 200 such that there is a line of symmetry between the rollers (132, 134). The line of symmetry means that the entirety of the first roller 132 and the second roller 134 appears substantially spherical or spherical when viewed along the line of symmetry. The first roller 132 and the second roller 134 have the same structure, size and shape and both include a radial center aligned with the common axis of rotation X. By this arrangement, the first and second rollers 132,134 are free to rotate about the common axis of rotation X. Furthermore, since the first and second rollers 132,134 are identical in structure, size, and shape, this means that the luggage 100 provided with the roller assemblies 104 will remain stable in the upright position (i.e., assuming a stable wheelbase is provided, such as using an eight-wheel configuration, where each roller assembly 104 is located at a respective bottom corner of the luggage).

The center support member 200 is connected to the wheel house 300 such that the center support member 200 can pivot/rotate with respect to the wheel house 300. More specifically, the center support member 200 is connected to the wheel housing 300 such that the center support member 200 is rotatable with respect to a second rotation axis Y orthogonal to the common rotation axis (first rotation axis X). The second rotation axis Y is offset from the center point of the body portion 202.

By having two orthogonal axes of rotation X, Y, the scroll wheel assemblies 104 can move the associated luggage 100 in any direction along a given plane without having to turn the luggage 100 itself. The scroll wheel assembly 104 thus has the capability of three hundred and sixty degrees of rotation.

Fig. 2B is a side view of the scroll wheel assembly 104. This is a "side" view of the first axis of rotation X toward the page, so that the scroll wheel assembly 104 is viewed parallel to the direction of travel. The first roller 132 comprises a circular cross-section and has a radial center aligned with the first rotation axis X. The radial distance from the radial center to the outermost end may be 10mm to 60mm, and more preferably 20mm to 30 mm. More preferably, the radial distance may be about 25mm (i.e. the diameter of the largest cross-section is about 50 mm).

As shown in fig. 2B, the connecting portion 204 of the center support member 200 is aligned with the second rotation axis Y. The second axis of rotation Y is offset from the radial centers of the first and second rollers 132 and 134 (and thus from the first axis of rotation X such that the two axes do not intersect). This allows for better control when maneuvering the luggage case as compared to a truck assembly having a zero offset axle. This is because less force is required to rotate the roller with zero deflection. Therefore, when the luggage case is manipulated by a person on the ground, the rollers are easily rotated against the person's will due to the ground resistance, so that the travel of the luggage case becomes difficult to control. Conversely, having a predetermined offset means that the rollers (132,134) are less likely to rotate accidentally due to ground/surface resistance. In this regard, the offset enables the operator of the luggage to better control the luggage.

Fig. 2C is a front view of the scroll wheel assembly 104. This is a "front" view of the attachment portion 204 of the center support member 200 positioned toward the rear of the scroll wheel assembly 104 such that the direction of travel is orthogonal to the plane of the page. In this view, the rollers (132,134) and the central support element 200 (but not the hub 300) share a line of symmetry aligned with the second axis of rotation Y. In this figure, the first roller 132 is to the left of the center support member 200 and the second roller is to the right of the center support member 200.

The first roller 132 includes a first portion 136, an intermediate portion 138, and an end portion 140. Although the first roller 132 is described in the present application as having portions, this will be understood to describe the side profile of the first roller, and thus the term "portion" does not necessarily refer to the various components of the first roller 132. The first portion 136 has a fixed width and its outer surface maintains a fixed radius with respect to the radial center/first rotational axis X (thus, the first portion 136 is substantially cylindrical in shape). The fixed width of the first portion 136 may be 2mm to 40mm, and more preferably 3mm to 15 mm. Even more preferably, the fixed width may be about 8 mm. The fixed radius of the first portion 136 may be 10mm to 60mm, and more preferably 20mm to 30 mm. Even more preferably, the fixed radius may be about 25 mm. The fixed radius is the maximum radius of the first roller 132. The intermediate portion 138 also has a fixed width, but its outer surface is convex and curved, the radial distance between the outer surface and the first axis of rotation X decreasing as the outer surface extends away from the first portion 136. Middle partThe fixed width of 138 may be a value in the range of 2mm to 40mm, and more preferably 5mm to 15 mm. Even more preferably, the fixed width may be about 8 mm. The radial distance of the intermediate portion 138 may gradually decrease from the maximum radius until the end portion 140 is reached. The intermediate portion 138 may include a radius of curvature having a value of 0.01mm^-1～0.1mm^-1More preferably 0.03mm^-1～0.05mm^-1. Even more preferably, the radius of curvature may be about 0.04mm^-1. The end portion 140 connects the middle portion 138 and continues the radius of curvature such that the first roller 132 is semi-spherical in shape such that the outer surfaces of the first portion 136, the middle portion 138, and the end portion 140 of the first roller 132 are substantially continuous and uninterrupted. In exemplary embodiments of the present application, the radii of curvature of the intermediate portion 138 and the end portion 140 may take different values from each other. In alternative embodiments of the present application, the radii of curvature may take the same value. Additionally or alternatively, at least one of the intermediate portion 138 and the end portion 140 may include a curved surface having a radius of curvature that varies along the curved outer surface.

The body portion 202 of the core backing component 200 is disposed between the first and second rollers 132,134 and is narrow in width such that the overall shape of the first and second rollers 132,134 and core backing component 200 is generally circular in cross-section (which may not provide a realistic look because the graphics have been modified to enlarge certain features and are not drawn to scale). For example, the width of the body portion 202 may be 2mm to 20mm, and more preferably 5mm to 12 mm. Even more preferably, the width of the body portion 202 may be about 8 mm. The gap between the main body portion 202 and the first roller 132 and the gap between the main body portion 202 and the second roller 134 may have the same width, and may be 1mm to 10mm, and more preferably 1mm to 5 mm. Even more preferably, the width of the gap may be about 3 mm. The narrow width and the narrow gap of the center support member 200 mean that the first and second rollers 132 and 134 are maintained close to each other. This allows the first and second rollers 132,134 to have a smaller footprint (i.e., including the space between the two rollers, the maximum surface area of the two rollers 132,134), allowing them to work together (much like a single roller) and minimizing frictional resistance (i.e., the greater separation of the rollers can interfere with the operability of the case when turning the associated case and create frictional resistance as it changes direction of travel, as compared to spacing the rollers a greater distance apart).

Fig. 3 is an exploded view of the scroll wheel assembly 104. Since the first and second rollers 132 and 134 are identical in structure, similar reference numerals will be used to describe relevant components.

The first and second rollers 132,134 each include an inner core 400, an outer tire 500, and an end cap 600.

The inner core 400 includes a hollow body 402, an inner frame 404 within the body 402, a socket 406 defined by the inner frame 404, an annular ring 408, a first open end 410, and a second open end 412 opposite the first open end.

The body 402 is generally frusto-hemispherical with a predetermined radius of curvature. In particular, the body 402 includes a tapered circular cross-section with a radius that is greatest at the first open end 410 and smallest at the second open end 412.

The ring 408 is disposed at the second open end 412 such that the ring 408 protrudes from the first open end 410. The annular ring 408 includes a lip 414 connected to a curved end face 416. The curved end surface 416 includes a gradually decreasing circular cross-section with a radius that decreases as the curved end surface 416 extends outwardly from the first open end 410.

The outer surface 418 of the body 402 includes at least two radial ribs 420, the radial ribs 420 being regularly spaced around the outer surface 418 and extending from the first open end 410 to the annular ring 408 at the second open end 412. Radial ribs 420 project radially outward from the outer surface 418.

The internal frame 404 includes a socket 406 in the form of a hollow tube concentrically arranged within the inner core 400 and set in place by radial support elements 422 extending between the socket 406 and the body 402. The socket 406 is capable of being coupled to the core backing component 200 and thereby enabling the associated roller (132,134) to be coupled to the core backing component 200. The radial support elements 422 maintain the socket 406 in a concentric arrangement with the central support element 200 such that the socket 406 is disposed in position along the first axis of rotation X.

The outer tyre 500 is hollow and has a generally frusto-hemispherical body with a first aperture 502 at one end and an opposing second aperture 504 at the other end. The body of the outer tire 500 includes a tapered circular cross-section that generally decreases as the outer tire 500 extends from the first aperture 502 to the second aperture 504.

The outer tire 500 includes an inner surface 506, the inner surface 506 mating with the outer surface 418 and the annular ring 408 of the inner core 400. This enables a tight friction fit to be provided between the outer tyre 500 and the inner core 400, ensuring that they can rotate together and not independently of each other. In this regard, the inner surface 506 is generally frusto-hemispherical in shape that may mate with the frusto-hemispherical shape of the core 400. The inner surface 506 also has an annular portion 508 adapted to fit around the lip 414 of the annular ring 408 of the inner core 400. Further, the inner surface 506 includes radial grooves 510 configured to receive the radial ribs 420 of the inner core 400. The radial grooves 510 and radial ribs 420 further ensure that the inner core 400 and outer tire 500 remain together and cannot rotate independently of each other when assembled.

The outer tire 500 also includes an outer surface 512, the outer surface 512 having a flat portion 514 and a curved portion 516. The flat 514 is an annular portion having a generally flat surface lying along a cylindrical plane at a fixed radial distance from the first axis of rotation X. The flat portion 514 is located at one end of the outer tire 500 and defines the first aperture 502 that receives the inner core 400. The flat portion includes a preset width, which may be 3mm to 15mm, and is preferably 8 mm. The flat portion has a fixed radius from the rotation axis X. The fixed radius may be 10mm to 60mm, and more preferably 20mm to 33 mm. Even more preferably, the fixed radius may be about 25 mm. The curved portion 516 is connected to the flat portion 514 and has a tapered circular cross-section, whereby the radius decreases as the curved portion 516 extends away from the flat portion 514. The curved portion 516 is convex and curved. The curved portion 516 may be a three-dimensional curve. Outer coverThe curvature of the surface may include a radius of curvature of 0.01mm^-1～0.1mm^-1And more preferably 0.03mm^-1～mm^-1. Even more preferably, the radius of curvature may be about 0.04mm^-1。

When the outer tire 500 is placed around the inner core 400, the curved end face 416 of the circular ring 408 of the inner core 400 protrudes through the second aperture 504 of the outer tire 500. The curvature of the curved end face 416 of the inner core 400 may match the curvature of the curved portion 516 of the outer tire 500 to provide a substantially continuous surface when combined together. The radius of curvature of the curved end surface 416 may be substantially the same as the radius of curvature of the curved portion 516. Additionally or alternatively, the radius of curvature of the curved end surface 416 may be different than the radius of curvature of the curved portion 516, but the rate of change of the radius of curvature of the curved portion 516 is the same or greater than the curved end surface.

The end cap 600 can fit within the second open end 412 of the inner core 400. The end cap 600 includes a curved outer surface that continues the curvature of the curved end face 416 and the curvature of the curved portion 516, thereby assuming a generally hemispherical shape when the curved outer surface of the end cap, the curved end face 416 and the curved portion 516 are brought together. In this regard, the radius of curvature of the end cap 600 may be substantially the same as the radius of curvature of the curved end face 416. Additionally or alternatively, the radius of curvature of the end cap 600 may be different than the radius of curvature of the curved end face 416, but the rate of change of the radius of curvature of the curved end face 416 is the same as the end cap 600 or greater than the end cap 600.

Thus, the fully assembled first roller 132 may include three different components capable of forming a substantially hemispherical roller.

The second roller 134 is identical in construction to the first roller 132, as described above, but when the roller assembly 104 is fully assembled, the second roller 134 is placed back-to-back with the first roller 132, thereby providing symmetry between the rollers (132, 134). In this manner, the rollers (132,134) together form a generally spherical shape.

For the core backing component 200, the core backing component includes a body portion 202 and a connecting portion 204.

Body portion 202 is generally disk-shaped with a truncated bottom 206. The truncated base 206 reduces the likelihood of drag or friction as the roller assembly 104 travels along an uneven surface, as it will be held at a higher position above the surface than the base of the rollers (132,134) and therefore is less likely to be in direct contact with the ground.

The dished portion of the body portion 202 has the same radius as the largest radius of the rollers (132,134), except for a truncated base 206 which is cut away along a plane orthogonal to the first and second axes of rotation X, Y. A through hole 208 is provided at the radial center of the disc-shaped portion of the main body portion 202, the through hole 208 being aligned with the first rotation axis X. The body portion 202 includes three concentrically arranged rings aligned on a single plane: a first inner ring 210 defining the through-hole 208, a second inner ring 212 having a larger diameter than the first inner ring 210, and an outer ring 214 having a largest diameter among the three rings. At least two radial spokes 216 are disposed between first inner ring 210 and second inner ring 212 and between second inner ring 212 and outer ring 214, respectively. The first mechanical fastener 218 is located within the through hole 208 and extends in two directions along the first rotational axis X so that the main body portion 202 can engage with the socket 406 of the inner core 400 of each corresponding roller (132, 134). For example, the first mechanical fastener 218 may be a rivet, bolt, screw, or any element that allows for the attachment of the rollers (132,134) to the center support member 200. The rollers (132,134) are connected to the center support member 200 in a manner that enables free rotation relative to the center support member 200. For example, the first mechanical fastener 218 may be fixed to the center support member 200, and the rollers (132,134) may rotate relative to the fixed first mechanical fastener 218. Alternatively, the rollers (132,134) may be fixed to the first mechanical fastener 218, and the first mechanical fastener 218 may be free to rotate relative to the center support member 200. In another alternative, first mechanical fastener 218 may not be fixedly attached to either component, but may be free to rotate relative to either of the rollers (132,134) and/or central support element 200.

The connecting portion 204 is a generally cylindrical fitting structure aligned with the second rotation axis Y, and the connecting portion 204 is capable of receiving a second mechanical fastener 220.

The wheel housing 300 is a rigid body that enables the truck assembly 104 to be attached to the luggage 100 in a stable and rigid manner. In this regard, the wheel housing 300 includes a top surface 302, a bottom surface 304, and an aperture 306, with the second mechanical fastener 220 being received by the aperture 306. The top surface 302 conforms to the contour of the luggage piece 100 at the corresponding attachment points. The bottom surface 304 is contoured to conform to the exterior contour of the luggage 100. The second mechanical fastener 220 may be a rivet, bolt, screw, or any element that allows the center support member 200 to be attached to the wheel housing 300. The center support member 200 is freely rotatably coupled to the wheel housing 300 with respect to the wheel housing 300. For example, the second mechanical fastener 220 may be fixed to the wheel housing 300, and the center support member 200 may rotate relative to the second mechanical fastener 220. Alternatively, the center support member 200 may be fixed to the second mechanical fastener 220, and the second mechanical fastener 220 may rotate freely with respect to the wheel housing 300. In another alternative, the second mechanical fastener 220 may not be fixedly attached to either component, but may be free to rotate relative to the center support member 200 and/or the wheel housing 300.

To assemble the roller assembly 104, a first mechanical fastener 218 may be placed in the through hole 208 of the center support member 200. The inner core 400 of each respective roller (132,134) is then disposed on one side of the central support element 200 such that the first mechanical fastener 218 is received by the respective receptacle 406 of each inner core 400. The inner cores 400 are arranged such that their largest diameter is closest to the central support element 200 and the smallest diameter is furthest from the central support element 200.

The outer tire 500 of each roller (132,134) is then disposed around the corresponding inner core 400 such that the radial grooves 510 of the outer tire 500 align with the radial ribs 420 of the inner core 400, thereby providing a friction fit.

The respective end cap 600 is then placed in the second aperture 504 of each outer tyre 500. The end cap 600 may be secured in place by a friction push fit arrangement, or an adhesive may be used. Similarly, an adhesive may be used to attach the outer tire 500 to the corresponding inner core 400.

The wheel housing 300 is placed in position such that the hole 306 extends along the second rotation axis Y and is aligned with the connecting portion 204 of the center support member 200. Then, the second mechanical fastener 220 is inserted through the hole 306 to be received by the connecting portion 204, thereby connecting the wheel housing 300 and the center support member 200 together. In some embodiments, the second mechanical fastener 220 may also be used to attach the wheel housing 300 to the main body 102 of the luggage case.

The roller assembly 104 may include a single material or a combination of materials to optimize the durability (or wear resistance) of the roller assembly 104 and to provide vibration damping and shock absorbing capabilities for the roller assembly 104. For example, the center support element 200, the inner core 400, the outer tire 500, and the wheel shell 300 may comprise one or more of the following materials: nylon, polypropylene, polycarbonate, thermoplastic elastomer, acrylonitrile butadiene styrene, metal alloy, plastic. In one embodiment of the present application, the center support element 200 may comprise a nylon material, the inner core 400 may comprise a polypropylene material, the outer tire 500 may comprise a thermoplastic elastomer material, the end cap 600 may comprise a combination of a polypropylene material and a thermoplastic elastomer material, the roller housing 300 may comprise a polypropylene material, and the first and second mechanical fasteners 218, 220 may comprise a metal, such as steel. Thermoplastic elastomers may include a mixture of plastic and rubber, which have both thermoplastic and elastomeric properties.

Fig. 4A and 4B are schematic diagrams illustrating temporary elastic deformation that may be experienced by the scroll wheel assembly 104 (represented by the ball 700 in these figures) of an embodiment of the present application during an impact event, for example, when the luggage 100 including the scroll wheel assembly 104 is dropped and the scroll wheel assembly 104 lands on the ground. In particular, fig. 4A shows a sphere 700 resting on a horizontal surface 702. The ball 700 approximates the shape of the scroll wheel assembly 104 and is for illustrative purposes only. The sphere 700 has a contact area 704 with the horizontal plane 702. The contact area 704 is the area where a portion of the outer surface of the sphere 702 (i.e., the relevant portion of the outer surface 512 representing the outer tire 500) contacts a horizontal surface 702 (i.e., may be the ground or any other surface upon which the luggage 100 rests or travels). This is the area that provides the greatest friction to enable the ball to travel along the ground (or remain stationary).

Fig. 4B shows the sphere 700 of fig. 4A, which hits a horizontal plane after falling from a predetermined height, and thus undergoes temporary elastic deformation such that the shape becomes an oblate spheroid 700'. In particular, the sphere 700 has been compressed along a vertical axis and has undergone a corresponding radial expansion in a horizontal plane, as indicated by arrows 706, the arrows 706 indicating the general direction of some expansion force. Accordingly, the contact area 704 is increased to provide an enlarged contact area 704'. The enlarged contact area 704 'means that most of the surface of the sphere 700/oblate spheroid ellipsoid 700' is in contact with the horizontal surface 702. This means that, for example, there is a larger surface area through which kinetic energy transfer can take place than in a cylinder with curvature along a single axis only. This in turn means that the sphere 700 has a greater ability to transfer its kinetic energy to the horizontal plane 702 due to elastic deformation.

Referring to fig. 4A and 4B, similar to the scroll wheel assembly 104 of the embodiments of the present application, it can be seen that the generally hemispherical shape of the scroll wheels (132,134) enables temporary elastic deformation upon impact of a surface, which increases the contact area between the scroll wheels (132,134) and the surface, such that kinetic energy of the scroll wheel assembly 104 (and luggage case 100) can be dissipated (i.e., transferred to the surface) more efficiently than conventional cylindrical scroll wheels. In particular, providing the center support member 200 instead of the conventional bifurcating clamp structure means that there is no clamping force that suppresses elastic deformation. In addition, the thermoplastic elastomer material (or any other suitable soft, elastically deformable material) of the outer tire 500 acts as a cushion, providing effective impact absorption characteristics. The shape of the outer tire 500 is generally hemispherical, which means that the rollers (132,134) can provide more impact absorbing material than is possible with conventional cylindrical rollers.

Because the rollers (132,134) are generally hemispherical in shape and the TPE material is used, the roller assembly 104 has a relatively low coefficient of restitution (COR) (i.e., the coefficient takes into account the relative velocities before and after impact, in this case with reference to a rigid steel surface).

The generally hemispherical shape of the wheels (132,134) may also deflect side impacts (i.e., impacts from external objects on the sides of the wheels when the associated luggage case 100 is upright). Generally, the rigid inner core 400 and end caps 600 (e.g., made of polypropylene or any other hard, rigid material) further enhance the deflection capability, thereby further protecting the roller assembly 104 and the luggage case 100.

Although the embodiments of the present application have been described herein with reference to the accompanying exemplary drawings, it should be understood that various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention.

For example, although the embodiments of the present application described herein refer to a generally hemispherical inner core 400, it should be understood that other shapes of inner cores 400 are possible while maintaining the impact deformation and impact absorbing characteristics of the roller assembly 104. More particularly, the inner core 400 may be substantially cylindrical, rectangular, or any other configuration. In this regard, the outer tire 500 may include an inner surface 506, the inner surface 506 matching the shape of the inner core 400 regardless of the shape of the inner core 400.

Further, while various values for the radius of curvature have been provided herein, it should be understood that in some embodiments, the radius of curvature may be a varying value. Therefore, it is not necessary that the radius of curvature take a single fixed value.

Embodiments of the present application provide examples of an eight-wheel configuration of luggage 100, but it will be appreciated that any other number of wheel configurations is possible. For example, one or more scroll wheel assemblies 104 may be included.

The embodiments of the present application described herein discuss a roller assembly 104 that includes at least an inner core 400, an outer tire 500, and an end cap 600. In an alternative embodiment, the entire structure of the roller may be made of a single material, such that the roller includes a single part rather than three component parts.

In the embodiments of the present application described herein, it is preferred that the material of the outer tire 500 be a softer material than the inner core 400, however, in alternative embodiments, the material of the inner core 400 may be a softer material than the outer tire 500, such that the inner core 400 provides damping and shock absorption.

The embodiment of the present application described herein with reference to fig. 2C provides a first roller 132 and a second roller 134 each having a flat portion 134. In an alternative embodiment, the rollers (132,134) may have a continuous radius of curvature such that no flat portion is present.