Many luggage items may include wheel assemblies to provide rolling support for the luggage on a support surface. One example of such rolling support includes four spinner wheel assemblies coupled to a bottom of the luggage case. The configuration of four spinner wheels allows a user to roll the luggage laterally in any direction without the need to tip the luggage case onto a pair of wheels. A spinner wheel assembly usually includes a housing for joining the wheel assembly to the luggage case, and a wheel support for rotatably connecting the wheel to a base of the housing so the wheel rotates about a generally vertical axis. To facilitate the rotation of the wheel support relative to the base, the wheel assembly may be configured with bearing structures, such as planar-oriented ball bearing units.
There are several drawbacks with a spinner wheel assembly configured with ball bearing units. Typically, the ball bearing units have a planar orientation, which orientation requires more surface area to create an acceptable load on the ball bearing unit. This results in a larger wheel assembly than is often desired, which impacts the weight and packing space of the luggage case. Also, the ball bearings in the ball bearing units provide only point contacts with the bearing races, which may cause deformation and wear on the upper and lower races. To reduce this wear, the races may be formed by a robust material, such as metal, which is relatively heavy. Non-metal materials may be used, which may be lighter than metal, but sometimes not as strong, and thus requires structural buttressing to resist unwanted deformation. This structural enhancement of non-metalic materials in this use results in relatively thick walls, increasing the overall weight and reducing the weight benefit of non-metal materials. In either case, the races constructed for a ball bearing adds extra weight to the wheel assembly. Another structure that adds extra weight to the wheel assembly in these traditional structures is a central axle, which is usually required for aligning the wheel support with the housing of the wheel assembly along the rotational axis of the wheel support. Accordingly including complex ball bearing units within such spinner structures may be undesirable and in particular for luggage where there is more recently a drive to reduce weight (and also cost), there may be a desire to avoid using such more complex bearing arrangements.
Documents that may be related to the present disclosure in that they include various approaches to wheel construction include U.S. Pat. Nos. 42,338, 145,769, 1,645,831, 2,437,588, and 3,231,926. These proposals, however, may not be suitable for use in luggage items, or may be improved.
It is therefore desirable to provide an improved luggage construction, in particular an improved luggage wheel assembly, which addresses the above described problems and/or which more generally offers improvements or an alternative to existing wheel assembly structures and construction methods.
USPTO Backgrounds
USPTO Backgrounds