Patent Publication Number: US-8533908-B2

Title: Ball wheel

Description:
FIELD OF THE INVENTION 
     The disclosed subject matter relates to a ball wheel assembly and a method of assembly thereof, and in particular to a ball wheel assembly for mounting on a piece of luggage. 
     BACKGROUND 
     Wheeled luggage cases are in widespread use today and greatly ease the traveler&#39;s movement in airports, railroad stations, etc. Many wheeled luggage items have retractable handles, which permit the traveler to pull or push the luggage item as he walks and have one hand free, and a number of wheels on which the luggage can roll. The wheels for wheeled luggage can typically pivot about an axis substantially perpendicular to a bottom surface of the luggage and facilitate movement of the luggage by rolling in the direction of the traveler&#39;s movement. 
     Wheels for wheeled luggage should provide the desired mobility while being rugged enough to withstand the wear and tear of normal use. A wheel assembly for luggage that attempts to address these issues is described in U.S. Pat. No. 5,393,079 to Wang. Wang describes a wheeled luggage assembly in which an L-shaped member is attached to the bottom of a body portion and an axle is disposed on the L-shaped member. Separate wheel protectors are fitted in recesses of the body portion and wheels are pivotally connected with the end of the axle. In another example attempting to address these issues, U.S. Pat. No. 5,794,744 to Lin describes a wheel assembly, which comprises a first subassembly and a second subassembly respectively mounted on an exterior side and an interior side of a frame of a luggage such that a space is formed between the first subassembly and the second subassembly for a wheel mount installed therein. The first subassembly and the second subassembly respectively include a central wheel well. A shaft has an end thereof screwed to the wheel mount and the other end thereof extending into the wheel well. A wheel is received in the central wheel well of the first subassembly and pivoted to the shaft for rotating, its distal end thereof pivoted to the wheel mount such that the wheel can turn freely. 
     Nevertheless, there remains a need for a wheel assembly for luggage that is mobile, rugged, and can be manufactured easily. 
     SUMMARY 
     The purpose and advantages of the disclosed subject matter will be set forth in and are apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter includes a ball wheel assembly. The ball wheel assembly includes a wheel ball and first and second legs. The legs include a mounting portion and a ring-shaped leg cover. The legs are secured together proximate to the mounting portions. The legs further include a leg ball bearing retaining ring and leg ball bearings. The leg ball bearing retaining ring and leg ball bearings are positioned between the leg cover and the wheel ball. The leg cover has an inner circumference defining an inner diameter and an outer circumference defining an outer diameter, and the inner diameter is between about one-half to about three-fourths, and preferably about two-thirds, the outer diameter. The leg cover has an inner surface, and the inner surface is concave relative to the wheel ball. The assembly further includes a top housing. The top housing includes a top housing cover, a housing ball bearing retaining ring, and housing ball bearings. The top housing is secured to the legs, and the housing ball bearing retaining ring, and housing ball bearings are positioned between the top housing cover and the wheel ball. 
     In some embodiments, the dimensions of the first and second legs can be identical. The first and second legs can be secured together with fasteners. The fasteners can be screws. The first and second legs can have mounting holes. Each mounting hole can be formed to securably receive the fasteners. 
     In some embodiments, only one of the first and second legs can have mounting holes. Each mounting hole can be formed to securably receive the fasteners. 
     In some embodiments, the first and second legs can each have a mounting hole formed to securably receive a fastener and a further mounting hole formed to allow a further fastener to pass through the further mounting hole. 
     In some embodiments, the inner surface of the leg cover can have a curvature approximately equal to a curvature of the wheel ball. 
     In some embodiments, the leg cover can be positioned to provide a spacing between the leg cover and the wheel ball to permit dirt to escape from between the leg cover and the wheel ball. The spacing can be defined by a diameter of the leg ball bearings. Each leg ball bearing can be spaced apart a distance of about 2 mm from a proximate leg ball bearing at a minimum. 
     In some embodiments, a cross-section of the wheel ball coplanar with the outer circumference of the leg cover can have a diameter between about one-half to about five-sixths the diameter of the wheel ball, and preferably about three-fourths the diameter of the wheel ball. 
     In some embodiments, the top housing cover includes an outer cover portion and an inner mounting portion. The top housing can be secured to the legs with fasteners through the top housing cover and the mounting portions. The outer cover portion can be made of plastic. The inner mounting portion can be made of forged aluminum. The inner mounting portion can be a skid. 
     The disclosed subject matter also includes a method of assembling a ball wheel. The method includes positioning first and second legs on opposite sides of a wheel ball and positioning first and second leg bearing retaining rings and first and second leg ball bearings between first and second leg covers and the wheel ball. The method also includes securing the first and second legs together proximate to a mounting portion and positioning a housing ball bearing retaining ring and housing ball bearings between a top housing cover and the wheel ball. The method also includes securing the top housing cover to the first and second legs. 
     The disclosed subject matter also includes a piece of luggage. The piece of luggage includes a luggage body and at least two ball wheels according to the disclosed subject matter. The two ball wheels are positioned on a surface of the luggage body along a first side. 
     In some embodiments, the piece of luggage can include two feet positioned along a second side opposite the first side. The piece of luggage can include two further ball wheels positioned along a second side opposite the first side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary embodiment of a ball wheel assembly according to the disclosed subject matter. 
         FIG. 2  is a front view of the ball wheel assembly. 
         FIG. 3  is a top view of the ball wheel assembly. 
         FIG. 4  is a side view of the ball wheel assembly. 
         FIG. 5  is a bottom view of the ball wheel assembly. 
         FIG. 6  is an exploded schematic view of the ball wheel assembly. 
         FIG. 7  is a schematic three-quarter front pictorial view of an exemplary embodiment of a piece of luggage including two ball wheel assemblies according to the disclosed subject matter, with portions broken away. 
         FIG. 8  is a schematic three-quarter front pictorial view of an exemplary embodiment of a piece of luggage including four ball wheel assemblies according to the disclosed subject matter, with portions broken away. 
         FIG. 9  is a schematic three-quarter front pictorial view of an exemplary embodiment of a piece of luggage including at least two ball wheel assemblies and a skid covering a portion of the luggage face according to the disclosed subject matter, with portions broken away. 
         FIG. 10  is a schematic three-quarter front pictorial view of an exemplary embodiment of a piece of luggage including at least two ball wheel assemblies and a skid covering substantially all of the luggage face according to the disclosed subject matter, with portions broken away. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the exemplary embodiments of the disclosed subject matter, an example of which is illustrated in the accompanying drawings. The device and method of the disclosed subject matter will be described in conjunction with the detailed description of the system. 
     As disclosed herein, the devices and methods presented can be used for making and using a ball wheel for a piece of luggage. 
     For the purpose of explanation and illustration, and not limitation, an exemplary embodiment is shown in  FIGS. 1-6 . Particularly and as illustrated, the ball wheel assembly  100  consists of a wheel ball  110 , first and second legs  126 ,  136 , and a top housing  142 . 
     As shown in  FIG. 6 , for example, the first and second legs  126 ,  136  each includes a leg housing  120 ,  130 . Each leg housing has a mounting portion  122 ,  132  and a ring-shaped leg cover  124 ,  134 . The ring-shaped leg cover  124 ,  134  has an inner circumference  172  and an outer circumference  174  defining an inner diameter  176  and an outer diameter  178 , respectively. The inner diameter  176  can be between about ½ to about ¾ the outer diameter  178 , and preferably about ⅔ the outer diameter  178 . The ring-shaped leg cover  124 ,  134  can be angled so as to flare out from a line perpendicular to top housing  142 , preferably about 20 degrees. The angling allows for the top housing  142  to have a potentially smaller diameter or footprint. 
     When the top housing  142  is parallel to the ground, e.g., when all four wheel balls  110  are in contact with the ground, there should be about ¾ inches to ⅜ inches clearance between the ground and a portion of the leg cover  124 ,  134  closest to the ground so that when the luggage  10  is pulled with only two wheel balls  110  in contact with the ground, typically with the luggage at an angle of about 40 degrees to 55 degrees, the leg cover  124 ,  134  will not be in contact with the ground. 
     The first and second legs  126 ,  136  are secured together proximate to the mounting portions  122 ,  132 . The first and second legs  126 ,  136  can be secured together with fasteners  220 . For example and without limitation, the fasteners  220  can be screws or any other suitable fastener. The first and second legs  126 ,  136  can be identical. The first and second legs  126 ,  136  can have mounting holes  123 ,  125 ,  133 ,  135  that are formed, for example by having threading, to securably receive fasteners  220 . Alternatively, only one of the first and second legs  126 ,  136  can have mounting holes  123 ,  125 ,  133 ,  135  that are formed, for example by having threading, to securably receive fasteners  220 . In this embodiment, the opposing leg  126 ,  136  can have mounting holes that allow fasteners  220  to pass through the mounting hole, for example by not having threading. In another embodiment, only one of the mounting holes  123 ,  125 ,  133 ,  135  for each of the first and second legs  126 ,  136 , can be formed, for example by having threading, to securably receive fasteners  220 , with the opposite hole  123 ,  125 ,  133 ,  135  allowing fasteners  220  to pass through the mounting hole, for example by not having threading. 
     The first and second legs  126 ,  136  each also includes a leg ball bearing retaining ring  190 ,  200  and leg ball bearings  180 ,  185 . The leg ball bearing retaining ring  190 ,  200  and leg ball bearings  180 ,  185  are positioned between the leg cover  124 ,  134  and the wheel ball  110 . The leg cover  124 ,  134  can have an inner surface  137  that is concave relative to the wheel ball  110 . The leg covers  124 ,  134  can be positioned to provide a spacing to permit dirt to escape from between the leg covers  124 ,  134  and the wheel ball  110 , and the spacing can be defined by a diameter of the leg ball bearings  180 ,  185 . The leg ball bearings  180 ,  185  can be made of metal, plastic, ceramic or any other suitable material and can have diameters, for example, of between about 2 and 4 mm, and preferably about 3 mm. The spacing can also be defined by a curvature of the inner surface  137  of the leg cover  124 ,  134  relative to a curvature of the wheel ball  110 , and the curvature of the inner surface  137  of the leg cover  124 ,  134  can be approximately equal to a curvature of the wheel ball  110 . Further, each leg ball bearing  180 ,  185  can be spaced apart a distance of about 2 mm from a proximate leg ball bearing  180 ,  185  at a minimum. A cross-section  230  of the wheel ball  110  defined by an imaginary plane coplanar with the outer circumference  174  of the leg cover  124 ,  134  can have a diameter between about one-half to about five-sixths the diameter of the wheel ball  110 , and preferably about three-fourths the diameter of the wheel ball  110 . The first and second legs  126 ,  136  being secured together on opposing sides of the wheel ball  110  likewise secures the leg ball bearing retaining  190 ,  200  and leg ball bearings  180 ,  185  therebetween. 
     The top housing  142  includes a top housing cover  145 , and optionally a housing ball bearing retaining ring  160 , and housing ball bearings  170 . The top housing cover  145  can include an outer cover portion  140  and an inner mounting portion  150 . The outer cover portion  140  can be made of plastic or any other suitable material. The inner mounting portion  150  can be made of forged aluminum or any other suitable material including, but not limited to plastic, zinc, steel or composite, such as those containing carbon. The housing ball bearings  170  can be of similar size and material as leg ball bearings  180 ,  185 . 
     The top housing  142  is secured to the legs  126 ,  136 . The top housing  142  can be secured to the legs  126 ,  136  using fasteners  210 . For example and without limitation, the fasteners  210  can be screws or any other suitable fastener. The outer cover portion  140  can have mounting holes  141  that are formed to receive fasteners  210 . The inner mounting portion  150  can have mounting holes  151  that are formed, for example by having threading, to securably receive fasteners  210 . The housing ball bearing retaining ring  160  and the housing ball bearings  170  are positioned between the top housing cover  145  and the wheel ball  110 . The top housing cover  145  being secured to the legs  126 ,  136  and proximate to the wheel ball  110  likewise secures the housing ball bearing retaining ring  160  and the housing ball bearings  170  therebetween. 
     In accordance with another aspect of the disclosed subject matter, a method of assembling a ball wheel assembly  100  is provided. The method includes positioning first and second legs  126 ,  136  on opposite sides of a wheel ball  110 . The first and second legs  126 ,  136  comprise first and second leg bearing retaining rings  190 ,  200  and first and second leg ball bearings  180 ,  185  positioned between first and second leg covers  124 ,  134  and the wheel ball  110 . The method also includes securing the first and second legs  126 ,  136  together proximate to a mounting portion  122 ,  132  of each leg housing  120 ,  130 . The method also includes positioning a housing ball bearing retaining ring  160  and housing ball bearings  170  between a top housing cover  145  and the wheel ball  110 . The method also includes securing the top housing cover  145  to the first and second legs  126 ,  136 . The ball wheel assembly  100  can include any of the features described herein above. 
     For the purpose of explanation and illustration, and not limitation, an exemplary embodiment of a piece of luggage  10  having two ball wheel assemblies  100  according to the disclosed subject matter is shown in  FIG. 7 . The piece of luggage  10  has a luggage body  20 . The two ball wheel assemblies  100  are positioned on a face  30  of the luggage body  20  proximate to a first edge  35  of the face  30 . The ball wheel assemblies  100  can be secured to the luggage body  10  by any appropriate securing means. For example and without limitation, the outer cover portion  140  of the top housing cover  145  can be placed on an inner surface  40  of the luggage body  10 , opposite an outer surface  50 , and the inner mounting portion  150  of the top housing cover  145  can be placed on the outer surface  50 . As described above, the top housing cover  145  can be secured to the legs  126 ,  136  by fasteners  210  through the outer cover portion  140  and inner mounting portion  150  of the top housing cover  145 , with the face  30  of the luggage body  20  secured therebetween. 
     The piece of luggage  10  can include a number of feet  60  positioned on the face  30  of the luggage body  20  proximate to a second edge  45  of the face  30 , opposite the first edge  35 . The feet  60  can be fastened to the luggage body  20  by any appropriate securing means. For example and without limitation, the feet  60  can be formed to securably receive fasteners  210 , for example by having threading. The outer cover portion  140  of the top housing cover  145  can be placed on an inner surface  40  of the luggage body  10 , with the inner mounting portion  150  disposed on an outer surface  50 , and the feet  60  can be fastened to the inner mounting portion  150  with fasteners  210 . Alternatively, the feet  60  can be fastened directly to the outer cover portion  140  with fasteners  210 , with the face  30  of the luggage body  20  secured therebetween, eliminating the inner mounting portion  150 . In this embodiment, the feet  60  can replace a number of ball wheel assemblies  100 , while using the outer cover portion  140  or inner mounting portion  150  for mounting. 
     For the purpose of explanation and illustration, and not limitation, an exemplary embodiment of a piece of luggage  10  having four ball wheel assemblies  100  according to the disclosed subject matter is shown in  FIG. 8 . The piece of luggage  10  can include two ball wheel assemblies  100  as shown and described with respect to  FIG. 7 , and can include two further ball wheel assemblies  100  positioned on the face  30  of the luggage body  20  along a second side  45  opposite the first side  35 . The two further ball wheel assemblies  100  can be fastened to the luggage body  20  by any appropriate securing means. For example and without limitation, the outer cover portion  140  of the top housing cover  145  can be placed on an inner surface  40  of the luggage body  10 , opposite an outer surface  50 , and the inner mounting portion  150  of the top housing cover  145  can be placed on the outer surface  50 . As described above, the top housing cover  142  can be secured to the legs  126 ,  136  by fasteners  210  through the outer cover portion  140  and inner mounting portion  150  of the top housing cover  145 , with the face  30  of the luggage body  20  secured therebetween. 
     For the purpose of explanation and illustration, and not limitation, an exemplary embodiment of a piece of luggage  10  having ball wheel assemblies  100  and a skid  90  according to the disclosed subject matter is shown in  FIG. 9 . In this embodiment, a skid  90  can be disposed on the face  30  of the luggage body  20 . The skid  90  can cover about half of the face  30 , extending from the first edge  35  of the face. The skid  90  can be made of plastic, or any other suitable material, and can have mounting holes  92  to receive fasteners  210 . For example and without limitation, the outer cover portion  140  of the top housing cover  145  can be placed on an inner surface  40  of the luggage body  10 , with the skid  90  disposed on a portion of the outer surface  50 . The top housing cover  145  can be secured to the legs  126 ,  136  by fasteners  210  through the outer cover portion  140  of the top housing cover  145  and the skid  90 , with the face  30  of the luggage body  20  secured therebetween. In this embodiment, the skid  90  can replace inner mounting portion  150  to secure ball wheel assemblies  100  to the face  30  of the luggage body  20  in accordance with any of the wheel assembly configurations described above. 
     For the purpose of explanation and illustration, and not limitation, an exemplary embodiment of a piece of luggage  10  having ball wheel assemblies  100  and a skid  90  according to the disclosed subject matter is shown in  FIG. 10 . In this embodiment, a skid  90  can be disposed on the face  30  of the luggage body  20 . The skid  90  can cover substantially all of the face  30 . The skid  90  can be made of plastic, or any other suitable material, and can have mounting holes  92  to receive fasteners  210 . For example and without limitation, the outer cover portion  140  of the top housing cover  145  can be placed on an inner surface  40  of the luggage body  10 , with the skid  90  disposed on a substantial portion of the outer surface  50 . The top housing cover  145  can be secured to the legs  126 ,  136  by fasteners  210  through the outer cover portion  140  of the top housing cover  145  and the skid  90 , with the face  30  of the luggage body  20  secured therebetween. In this embodiment, the skid  90  can replace inner mounting portion  150  to secure ball wheel assemblies  100  to the face  30  of the luggage body  20  in accordance with the configurations described above. Alternatively, the skid  90  can replace inner mounting portion  150  to secure feet  60  to the face  30  of the luggage body  20  in accordance with the configurations described above. 
     While the disclosed subject matter is described herein in terms of certain exemplary embodiments, those skilled in the art will recognize that various modifications and improvements can be made to the disclosed subject matter without departing from the scope thereof. As such, the particular features claimed below and disclosed above can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter should be recognized as also specifically directed to other embodiments having any other possible permutations and combinations. It will be apparent to those skilled in the art that various modifications and variations can be made in the systems and methods of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.