AU2018101682A4 - Wheeled luggage - Google Patents

Abstract

The present invention provides wheeled luggage (1) including a chassis (2) having a pair of spaced apart wheels (3, 3') rotatably mounted on a common wheel axis. A handle assembly (5) extends from the chassis between the wheels and a ground engaging foot (6) is provided on the chassis spaced from the wheel axis. The luggage also includes a bag (7) having at least one closable cargo compartment, the bag being supported by the chassis (2) for securely enclosing and carrying objects. The wheels have a diameter of between 160mm and 200mm. Fig 1. co L()L L() u.

Description

WHEELED LUGGAGE

FIELD OF THE INVENTION [0001] The present invention relates to wheeled luggage and in particular luggage designed to traverse rough and uneven ground.

[0002] The invention has been developed primarily as luggage for school students. However, it will be seen that the invention may have be used in other environments where a high mobility wheeled bag is required.

BACKGROUND OF THE INVENTION [0003] The following discussion of the prior art is intended to place the invention in an appropriate technical context and enable the associated advantages to be fully understood. However, any discussion of the prior art throughout the specification should not be considered as an admission that such art is widely known or forms part of the common general knowledge in the field.

[0004] It is well recognised that any activity that involves repeated biomechanical load can cause significant injuries to the musculoskeletal systems. For instance, the combination of heavy load and repetition which is often the result of repeatedly carrying heavy weights in day to day life may result in musculoskeletal disorders of the arms, shoulders, back and spine. These negative effects can be severely exacerbated by unevenly loading and poor posture, particularly of the back and spine.

[0005] Moreover, repeated biomechanical load applied during childhood and adolescence as an individual grows, may lead to irregular development and long term and/or permanent disabilities. One particularly susceptible group are school children who are often required to carry books and equipment every day to and from schools. Traditional school suitcases and duffel-type soft bags are normally carried on one side of the body with one hand leading to a highly unbalanced load and poor posture of the user.

[0006] For this reason, backpacks are now promoted as a solution to enable loads to be at least carried evenly on the back and shoulders. However, backpacks have significant shortcomings because they do not solve the problem of over loading. In addition, backpacks, if incorrectly adjusted or worn, provide little or no advantage over other types of school bags.

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-2[0007] The provision of wheels on luggage is known. Many bags, and particularly suitcases and the like for travelling are fitted with wheels so that rather than the mass of the bag being borne by the user, it is supported on the wheels and pulled or pushed. Such luggage may be known by terms including wheelie bags or trolley luggage. However, this type of luggage is primarily designed for use on even, flat and hard surfaces as might be encountered in major transport hubs such as airports. They are not designed suitable for being wheeled over uneven and/or soft terrain, and as such are unsuitable as school bags.

[0008] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

SUMMARY OF THE INVENTION [0009] Accordingly the invention provides wheeled luggage including: a chassis having: a pair of ground engaging wheels rotatably mounted on a common axis, said wheels spaced apart and disposed at or adjacent opposing lateral peripheral sides of said chassis, wherein the common axis is disposed along axis an adjacent rear peripheral edge of the chassis; a handle assembly extending upwardly from the chassis between the wheels; and a ground engaging foot on the chassis spaced from the wheel axis, said foot and wheels providing a platform for supporting the bag in an upright orientation; a bag having at least one closable compartment, the bag being supported by the chassis for securely enclosing and carrying objects wherein the wheels have a diameter of between around 160mmm and 200mm.

[0010] Preferably, the wheels are 180mm in diameter.

[0011] Preferably, the chassis includes a tub having a rear sidewall projecting from a rear peripheral edge of the tub.

[0012] Preferably, the wheels include a tire having an increased diameter raised portion and a reduced diameter shoulder portion.

[0013] Preferably, the bag is selectively detachable from the chassis.

[0014] Optionally, the bag includes a shoulder harness enabling the bag to be worn as a backpack.

[0015] Reference throughout this specification to “one embodiment”, “some embodiments”

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-3or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS [0016] A preferred form of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0017] Figure 1 is a perspective view of wheeled luggage according to a preferred embodiment of the invention;

[0018] Figure 2 is a part view of the wheel tire in accordance with another aspect of the invention;

[0019] Figure 3 is an underside view of the luggage shown in Figure 1 displaying the tub and luggage footprint;

[0020] Figure 4a to 4c are front, and side views of the luggage shown in Figure 1;

[0021] Figures 5, 6 and 7 are schematic representations comparing luggage in accordance with the invention equipped with wheels of different diameters;

[0022] Figure 8a and 8b are schematic representations of the luggage shown in Fig 1 in respect of common obstacles; and [0023] Figure 9a and 9b are side and perspective views of a handle in accordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0024] Referring to the Fig. 1, the invention provides wheeled luggage 1 for use over rough and/or uneven terrain. The luggage includes a chassis 2 having a pair of spaced apart wheels

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-43, 3' rotatably mounted on a common wheel axis, a handle assembly 5 extends from the chassis between the wheels and a ground engaging foot 6 is provided on the chassis spaced from the wheel axis. The luggage also includes a bag 7 having at least one closable cargo compartment, the bag being supported by the chassis 2 for securely enclosing and carrying objects. Various features of the luggage will now be described with reference to the drawings.

Chassis [0025] The chassis 2 includes a tub 10 for receiving and supporting the bag. In this embodiment the tub includes a generally continuous D-shaped tub floor 11, as seen in Fig 3. The tub includes a pair of wheel housings 12 spaced apart on opposite sides of the tub floor and defining the common wheel axis Aw disposed generally along a rear edge of the tub floor. A rear side wall 13 extends from the floor around at least the rear peripheral edge of the floor to join the wheel housings. The tub floor, side wall and wheel housings forming a generally continuous surface thereby providing protection against ingress of water and/or debris into the bag from beneath.

[0026] In this embodiment the tub, side walls and wheel housings are of a single piece molded construction. In addition, each wheel housing includes a mud guard 14 for further protection of the user and bag from mud, debris and/or water which may be thrown up by the wheels. Preferably, the tub is injection moulded from a plastics material such a polypropylene.

[0027] A ground engaging foot 6 is disposed at a front peripheral edge 15 of the tub floor, opposite the wheel axis, on an underside portion of the floor. As seen in Fig 3, the foot 6, in combination with the paired wheels 3, 3’, provide for a triangulated stability footprint when standing the bag on a surface including uneven terrain.

Cargo Compartments [0028] As seen in Figs. 4a to 4c, in this embodiment, the luggage is provided with a bag including a fabric cargo section comprising three separate compartments. A first front compartment 20 for small items, the main middle compartment 21, and a rear laptop pocket 22 against the rear of the bag above to axle. The compartments are preferably formed from a water-resistant fabric material such as nylon bonded to 1 mm EVA. It will also be appreciated that the bag may be provided with other configurations, sizes and numbers of compartments.

[0029] The overall width and height of the luggage are optimised to minimise outer

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- 5dimensions while maintaining appropriate carrying capacity, particularly for predetermined items. Reducing the exterior dimensions of the bag is advantageous for manageable manoeuvring in tight spaces such as on public transport or the like and so as to fit within school lockers.

[0030] In this embodiment, as seen in Fig. 4a the luggage has been designed to accommodate a laptop computer 23 having dimensions of 250mm x 360mm which correspond to a standard size 15-inch laptop computer 23. It is noted that the laptop must fit between the moulded wheel housing 12. As such, the laptop dimensions generally dictate the minimum width and to a degree the height of the cargo compartments and the overall minimum dimensions of the luggage as seen in Fig. 4a to 4c. The luggage with a width of around 370mm and height of around 510mm and a depth of around 220mm.

[0031] It will be noted that the laptop compartment 22 is directly adjacent the rear side wall 13 of the tub. This way the comparatively rigid tub and side wall offer increased protection for the laptop. In addition, the weight of the laptop is positioned close to the axle of the wheels aiding stability of the luggage both when stationary and during movement.

[0032] Of course, the luggage may be constructed with other dimensions without departing from the scope of the invention. For instance, the luggage may be increased in size to accommodate a larger laptop or reduced so for a smaller laptop and smaller overall luggage. In other embodiments the dimensions of the luggage may be selected based on other considerations unrelated to the carriage of a laptop or other electronic device. For instant the dimensions may be chosen to accommodate particular items of sporting or musical equipment, or to fit within specified maximum dimensions.

[0033] In another embodiment, the bag section is removable from the chassis, so it may be used independently of the chassis as a conventional non-wheeled bag. The bag may be selectively attachable to the chassis by means of snap locking clips, zippered fasteners or other selectively engagable fastening systems. This system also allows the chassis and/or bag sections to be individually replaced or repaired as required.

[0034] In a further embodiment, the luggage is convertible in that it includes a harness having a pair of shoulder straps enabling shoulder mounting as a back-pack. This embodiment may include padded upper and lower support panels for extra back protection. In this embodiment, the bag may be selectively detachable from the chassis so that when used as a

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-6backpack the chassis and wheels are not used.

[0035] In a further embodiment, the middle compartment 21 includes removable inserts for dividing the middle compartment into discrete storage areas based on the user’s requirements. For example, in one application, the inserts are configured to divide the middle compartment 21 into discrete areas adapted to house camera components, where each component is prevented from contacting the adjacent component by a resilient insert wall. In another application, the inserts are configured to separate the middle compartment 21 into separate areas adapted to house tools used by artists, including hair and make-up artists. In a further potential common use, the luggage is used to store digital office tools to be used by individuals who use telecommunications technologies to earn a living and, more generally, work remotely.

[0036] Using these inserts, the middle compartment may be customised for a variety of applications depending the user’s requirements.

Handle assembly [0037] The handle assembly 5 extends from the rear of the luggage above the wheel axis Aw. The handle assembly is disposed on the tub exterior so as not to encroach on the internal compartments. This allows the internal laptop compartment of the bag to have a generally flat shape adjacent the handle complementing the shape of the laptop or objects.

[0038] In this embodiment, the handle includes a single extendable aluminium shaft 30 located on the luggage axis between the wheels and a D shaped handle piece 31 which provides stability to the bag through increased grip improving handling over rough terrain. The handle can be seen in more detail in Fig 9a and 9b. The shaft 30 is selectively extendable from a retracted position to an extended position for ergonomic wheeling the luggage. In this embodiment a selectively engageable latch system is provided to hold the handle in the extended or retracted positions.

Wheel assembly [0039] A feature of the invention is that it provides the ability to traverse uneven terrain. The wheels of the luggage are oversize when compared to exiting wheeled luggage and have a diameter between around 160mm to around 200mm. Preferably, the wheels have a diameter of 180mm. This provides the luggage with an axle height of between 80mm and 100mm. Preferably, the axle height is around 90mm which provides a ground clearance dimension of

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-7around 80mm (see Fig 4b) vastly improving clearance of the luggage over obstacles. As will be explained the wheel size has been carefully optimised.

[0040] Larger wheels are more rotationally efficient and tend to better roll over minor obstacles rather than jamming or being caught in comparison to smaller diameter wheels. The ability of a wheel to roll over an obstacle is directly related to the axle height which in turn is a result of the wheel diameter. In addition, larger diameter wheels provide superior angles of approach for smaller obstacles and are less include to fall into potholes and indentations. They also generally provide a larger contact patch with the ground due to a less sharp radius of curvature of the ground contacting circumference, helping the wheel to reduce downward pressure per unit of contact patch. This helps the wheels to “float” over soft ground rather than sink. Furthermore, the comparative large wheels and greater axle clearance also aids in holding the luggage above standing ground water. Thus, larger diameter wheels provide a number of advantages when wheeling the luggage over rough, uneven and soft terrain.

[0041] However larger wheels have trade-offs in that, luggage stability, weight, size and encroachment on carrying capacity are all negatively affected as wheel size increases. Consequently, the size of the wheels of the luggage has been optimised to maximise rolling performance without significantly hampering other operational considerations. The optimisation process of the design will now be explained.

[0042] Notwithstanding the above discussion on rolling performance, stability of wheeled luggage is recognised by the inventors as a particularly important consideration. Other than the ability to be rolled rather than carried, one of the advantages of wheeled luggage is that it is configured to stand upright. This not only places the handle in a convenient position for pulling or pushing the luggage, it also presents the handle when extended, at an ergonomic level so that the user is not required to bend down to reach the handle. However, standing the luggage upright increases the height of the combined luggage/cargo centre of mass (CM), above the ground which may adversely affect stability. One option is to lower the luggage compartment to reduce the height of the CM thereby increasing stability. However, to maintain the same carrying volume, and maintain ergonomics, such an approach would lead to a larger foot print and long handle which are undesirable, particularly for using the luggage in busy places such as on public transport.

[0043] Referring to Figure 5 to 7, schematics of wheeled luggage dimensions is shown where the stability due to payload been analysed in the longitudinal (forward - rearward) two2018101682 13 Nov 2018

-8dimensional plane. The lateral plane will be discussed later. The envelope of the most probable centre of mass CM of the luggage has been determined considering non-central longitudinal loading situations. For instance, if the luggage were loaded with a heavy item in a front or rearmost pocket with little other payload. To maintain stability of the luggage when standing, it is important that the CM falls well within the extremities of the support positions provided by the respective contact points of the wheels Cw (directly under the axle) at the rear, and the ground engaging foot C6at the front.

[0044] In the Fig. 5, the wheel diameter is given by Dw , the radius of which corresponds to the axle height Ha. The axle height Ha and tub length LTthen dictate the inclination angle β° of the base and correspondingly, the lean angle a° from vertical of the luggage.

[0045] Figs. 5, 6 and 7, provide a schematic comparison of the effect on luggage lean angle and the resultant position of the CM to determine luggage stability. Specifically, these figures display how increasing the wheel diameter and axle height will increase the lean angle a° of the luggage and show how the relative position of the expected CM is affected in relation to the support base.

[0046] Fig 5 shows a wheel size of 160mm (D160), Fig 6 shows a wheel size of 180mm (D180), while Fig 7 shows a wheel size of 200mm (D200). As can clearly be seen by comparing Fig 5, 6 and 7, increasing Dw increases axle height and also will increase the lean angle a° of the luggage from vertical. As a result, the centre of gravity CM is positioned further toward the front of the luggage over the contact point C6 of the ground engaging foot 6. The luggage becomes progressively less stable as the CM approaches a position directly over contact point of the foot, C6, and will be unstable when the CM passes beyond the foot. It is also noted that the distance between the respective contact points Cw on one side, and C6 on the other reduces as the inclination angle β° increases.

[0047] One solution, without increasing the dimensions of the luggage base, is to extend the foot 6 downwardly to compensate for the additional angle of lean caused by the elevated axle. Another is to rake the tub base to offset the increased angle of lean. However, both solutions have drawbacks. Some of these drawbacks are clear such as having a protuberance in the case of extending the foot or changing the shape of the payload compartment in the case of a rakes tub. However perhaps significantly, both solutions will reduce the approach/departure clearance angle at the front of the luggage. For instance, descending stairs or curbs may cause the ground engaging foot 6 to “hang” or clip the higher-level stair, which is undesirable.

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-9[0048] As noted above neither solution was considered acceptable and therefore a limit on the lean angle a of the luggage from vertical angle was imposed. Moreover, given that the bag is designed to be used on uneven terrain, a margin of stability was applied. The CM should be positioned well between the respective contact points Cw on one side, and C6 on the other. In this regard, a wheel diameter of greater than about 200mm was determined to begin to result in significant trade-offs of stability, weight, size and encroachment on baggage space. Less than 160mm diameter was regarded as not providing sufficient advantages during use over rough terrain as discussed, while a 180mm wheel diameter was determined as the optimum wheel size.

[0049] Other considerations were also considered in confirming an optimal wheel size. For instance, with reference to Fig. 8a, the typical curb height is 100mm. When moving over curbing and guttering the user is usually travelling at speed with a bag incline Φ of approx. 4550 degrees. Under such conditions, 180mm wheels allow the luggage to ride up and over the curb without substantial loss of momentum.

[0050] Another common obstacle faced is stairs as shown in Fig. 8b. Current standards require a stair riser height variance from 150mm to 215mm. Based on typical pull angles 0° of between 70-80 degrees the wheels provide the luggage with sufficient clearance to roll up stairs without significantly impacting other performance aspects.

[0051] In the lateral axis of the luggage, stability is provided by the lateral spacing of the wheels or the wheel-track. As previously noted, the luggage has been designed to accommodate a 15-inch lap top computer requiring a laptop compartment of at least 250mm in width, in turn setting the luggage width of around 370mm as seen in Fig 4a. For optimal stability the track width is maximised such that the wheels are at the extreme lateral edges of the chassis to maximise stability for a given overall luggage width. This also reduces encroachment of the wheel and wheel housings into the cargo area. Again, a balance between stability and luggage width must be stuck.

Wheels [0052] The wheels include a non-marking tire incorporating a unique tread pattern optimised to provide low friction ride on hard surfaces while providing a wider tread for softer surfaces. Referring to figure 2 which displays a detailed view of the luggage tire, the tread profile can be seen. The tread includes a first narrow central portion 41 of increased diameter with respect to

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- 10smaller diameter shoulder portions 42. The central portion 41 provides a low friction narrow contact area when the luggage is wheeled on hard surfaces such as concrete. The wider shoulder portions 42 provide a wider contact patch to prevent the wheels sinking into softer surfaces such as sports grounds and grass areas. In this way, the wide tread pattern assists the luggage to ride on top of soft surfaces.

[0053] The wheels are attached to the chassis on nylon bushings removing the need for steel bearing minimising maintenance.

[0054] In further embodiments the invention includes a suspension system fitted into the wheels and/or axle.

[0055] It will be appreciated that the invention provides wheeled luggage which is particularly suited to traversing uneven, rough and damp surfaces. However, the ability of the luggage to traverse such surfaces has been provided without significant impact to other practical aspects such as stability, load carry capability, compactness and protection of cargo.

[0056] Advantageously, due to the centre of gravity CM being so close to the common wheel axis Aw, manoeuvring the luggage (1) using its handle when loaded in a tilted configuration, such as is most commonly foreshadowed, is relatively easier than comparable prior art luggage that use spinning castor wheels affixed to the bottom surface. Indeed, the inventors have found that manoeuvring the luggage of the present invention when loaded generally feels effortless, stable and light.

[0057] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0058] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention.

Claims (6)

1. Wheeled luggage including:

a chassis having:

a pair of ground engaging wheels rotatably mounted on a common axis, said wheels spaced apart and disposed at or adjacent opposing lateral peripheral sides of said chassis, wherein the common axis is disposed along an axis adjacent a rear peripheral edge of the chassis;

a handle assembly extending from the chassis between the wheels; a ground engaging foot on the chassis spaced from the wheel axis said foot and wheels providing a platform for supporting the bag in an upright orientation; and a bag having at least one closable compartment, the bag being supported by the chassis for securely enclosing and carrying objects, wherein said wheels have a diameter of between around 160mmm and 200mm.

2. Wheeled luggage according to claim 1 wherein the wheels have a diameter of around 180mm.

3. Wheeled luggage according to claim 1 or 2 wherein the chassis includes a tub having a rear sidewall projecting from a rear peripheral edge of the tub.

4. Wheeled luggage according to any one of the preceding claims wherein the wheels include a tire having an increased diameter raised portion and a reduced diameter shoulder portion.

5. Wheeled luggage according to any one of the preceding claims wherein the bag is selectively detachable from the chassis.

6. Wheeled luggage according to any one of the preceding claims wherein the bag includes a shoulder harness enabling the bag to be worn as a backpack.