Abstract:
A yo-yo includes first and second side members, an axle extending between the side members, a string interconnected with the axle, and at least one weight releasably mounted to one of the side members in a first location, and moveable to a second location.

Description:
FIELD OF THE INVENTION 
     The invention relates to yo-yos, and more particularly to the weight and weight distribution of a yo-yo. 
     BACKGROUND 
     Many yo-yo tricks require the yo-yo to spin freely at the end of the string without climbing up the string. A yo-yo spinning freely at the end of the string is commonly said to “sleep” or “dwell.” Ideally, a player will cause the yo-yo to sleep, and perform the desired trick while the yo-yo is spinning. After the trick has been executed, the player tugs on the string and the yo-yo climbs up the string again (referred to herein as “waking up” the yo-yo). 
     The sleep time for a yo-yo will typically increase as the angular momentum of the yo-yo increases. Angular momentum is a function of the rotational speed of the yo-yo and the weight distribution in the yo-yo. It is known to provide a weighted ring that may be mounted on or removed from the yo-yo to alter the yo-yo&#39;s angular momentum. 
     Another factor in performing yo-yo tricks is the weight of the yo-yo. Some tricks are more easily performed with a lighter-weight yo-yo, and some tricks require a heavier yo-yo. Some yo-yo players own several yo-yos of various weights to perform these various tricks. 
     SUMMARY 
     It is desirable to provide a yo-yo having an adjustable weighting system that permits several different weight arrangements to accommodate a wide range of yo-yo tricks. Such an adjustable weighting system is also desirable because it permits, to a certain degree, customization of sleep time to fit the skill level of the yo-yo player and the trick sought to be executed. In this regard, a yo-yo having an adjustable weight system may replace several non-adjustable yo-yos. 
     The present invention provides a yo-yo including first and second side members, an axle extending between the side members, a string interconnected with the axle, and at least one weight releasably attached to at least one of the side members at a first location and movable to a second location on the side member. 
     A plurality of retainers may be interconnected with the side members, and the weights may be releasably held in place by the retainers at selected locations. Preferably, the retainers include at least one resilient wall such that when the weights are inserted at least partially into the retainers, the resilient wall creates a press-fit connection between the weights and the retainers. Alternatively, the retainers may include hooks, threaded fasteners, clips, or hook-and-loop fasteners. The weights may be arranged in an eccentric weighting pattern, and the pattern of weights may be different in one side member than the pattern in the other side member. The weights are preferably sphere shaped members, such as ball bearings, but the weights may be provided in substantially any shape. 
     The invention also provides a cover releasably mounted over a cavity in one of the side members. The cover is preferably press-fit over the cavity, and an optional insert may be sandwiched between the cavity and the cover. A tool may be provided having an elongated portion that may be used to pry the cover from the cavity. 
     One advantage of the present invention is that it permits adjustment of the weight and weight distribution of the yo-yo to modify the yo-yo&#39;s angular momentum. 
     Another advantage of the present invention is that it includes a plurality of retainers in which weights are releasably received such that the weights may be moved from one position to another to adjust the weight distribution. 
     Another advantage of the present invention is that it provides a cover that extends across the cavity in which the weights are retained, and that may retain a decorative insert. 
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a yo-yo embodying the present invention. 
     FIG. 2 is an exploded view of the yo-yo of FIG.  1 . 
     FIG. 3 is a perspective view of the yo-yo shown in FIG.  1  and illustrating how a cover may be removed. 
     FIG. 4 is a cross-section view of the yo-yo shown in FIG.  1 . 
     FIG. 5 is a view taken along line  5 — 5  in FIG.  4 . 
     FIG. 6 is an enlarged view of a portion of FIG.  4 . 
    
    
     Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify steps of a method or process is simply for identification and is not meant to indicate that the steps should be performed in a particular order. 
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a yo-yo  10  embodying the invention and including a pair of side members  14  and a string  18 . The illustrated yo-yo  10  is an Imperial or tournament style yo-yo, but the invention may alternatively be embodied in a yo-yo of another style, such as a Butterfly style in which the side members  14  are inverted and flare outwardly. As used herein, unless otherwise specified, “yo-yo” encompasses all styles and shapes of yo-yos. 
     FIG. 2 illustrates other components of the yo-yo  10 . Each side member  14  has associated therewith a cap or cover  22 , an optional insert  26 , a plurality of weights  30 , and a hub  38 . The yo-yo  10  also has a bearing assembly that includes a pair of bearing supports  46  and a bearing  50  supported by the bearing supports  46 . An axle  54  extends through the side members  14  and bearing supports  46 , and is threaded into a nut  58  to hold the yo-yo  10  together (see also FIG.  4 ). The illustrated bearing assembly is an optional part of the invention. The string  18  may be interconnected with the axle  54  either through the illustrated bearing assembly, through an alternative bearing assembly, or through direct contact between the string  18  and the axle  54 . 
     With additional reference to FIGS. 4 and 6, the bearing supports  46  include base portions  62  and insert portions  70  of reduced diameter that extend away from the base portions  62 . The bearing width  74  is slightly smaller than the combined lengths of the insert portions  70 , and the bore through the bearing  50  is of slightly larger diameter than the outer diameter of the insert portions  70  to promote low friction rotation of the bearing  50  on the bearing supports  46 . 
     As seen in FIGS. 2 and 4, the illustrated axle  54  is a bolt having a head  78  with flats at one end, and a threaded portion  82  at the opposite end. The hub  38  of one of the side members  14  may include flats such that the bolt head  78  does not rotate with respect to the hub  38  when received therein. The nut  58  may be positioned within the hub  38  of the other side member  14  such that the nut  58  does not rotate with respect to the hub  38 . In this regard, the head  78  and nut  58  are rotationally fixed with respect to the respective side members  14 . Alternatively, the axle  54  may be a threaded stud that is integrally formed with or permanently affixed to one of the side members  14 . As an alternative to using the nut  58 , the axle  54  may be threaded directly into a threaded bore in the other side member  14 . Alternatively, the axle  54  may be press-fit into the other side member  14  instead of threaded. 
     Referring to FIG. 4, the spacing  86  between the side members  14 , also known as “string gap,” may be adjusted by relative rotation between the side members  14 , causing the side members  14  to be drawn closer together or moved farther apart due to the threads  82 . The side members  14  may thus be moved from the position shown in solid lines in FIG. 4 to the position shown in phantom. The smaller the string gap, the easier it becomes to wind the string  18  on the bearing  50 . The string gap  86  thus at least partially affects the ease with which the yo-yo  10  may be made to sleep and wake up. 
     Referring to FIGS. 2 and 3, the covers  22  may be transparent, translucent, colored or opaque, and extend over a cavity  94  in the side members  14 . The covers  22  are secured over the cavities  94  by a pressure fit, but may alternatively be fastened, snap-fit, or secured over the cavities  94  in any suitable manner. Each side member  14  includes a recess  98  extending under the cover  22  associated therewith. A tool  102  may be provided having a narrow or elongated portion that is insertable into the recesses  98  to pry the covers  22  out of the cavities  94  with the motion shown in FIGS. 3 and 4. The optional inserts  26  may be pieces of paper, plastic, “pogs” displaying a popular character or person, or other material bearing a design or picture. The inserts  26  are trapped in the cavities  94  by the covers  22 . 
     The illustrated weights  30  are sphere-shaped weights, such as steel ball bearings. However, the weights  30  may be provided in substantially any shape. It is preferred that the weights  30  be discrete units that may be positioned at various positions within the cavities  94 . Each weight  30  has its own center of gravity, and is positionable within the cavities  94  such that the weight  30  center of gravity is not on the yo-yo&#39;s axis of rotation (i.e., the weight  30  center of gravity is not on the axle  54 ). 
     Turning now to FIGS. 2,  4 , and  5 , the illustrated cavities  94  include a plurality of retainers  106 . The illustrated retainers  106  include walls  110  extending longitudinally outwardly from the side members  14 . The thickness and material (e.g., plastic or thin aluminum or steel) of the walls  110  causes the walls  110  to be substantially resilient. The walls  110  flex to permit the weights  30  to be pressed into the retainers  106 , and provide a bias radially inward to hold the weights  30  within the retainers  106 . Protrusions  114  (FIG. 5) may be used to ensure that the weights  30  are held within the retainers  106  by compression on three sides. In this regard, the weights  30  may be press-fit at least partially within the retainers  106  to hold the weights  30  at selected locations within the cavities  94 . The tool  102  may be used to remove the weights  30  from the retainers  106 . 
     It should be noted that, although the illustrated adjustable weight system includes retainers  106  having resilient walls  110 , other retainers are contemplated and are considered within the scope of the invention. For example, the retainers may include hooks onto which the weights are mounted, threaded fasteners or clips securing the weights  30  within the cavities  94 , or hook-and-loop fasteners (e.g., Velcro). The retainers  106  themselves may be movable in alternative embodiments, and may alternatively be formed integrally with the weights  30  and movable with the weights. 
     In the illustrated embodiment shown in FIG. 2, there are three retainers  106  at a relatively large radial distance from the axle  54 , and three retainers  106  at a relatively small radial distance from the axle  54 . The weights  30  may be inserted into all of the retainers  106 , or only selected retainers  106 . Some of the weights  30  may be inserted into the retainers  106  that are at the large radial distance from the axle  54 , and some may be inserted into the retainers at the small radial distance from the axle  54 . Customized combinations and patterns of weights including eccentric weighting arrangements may also be created. Also, the number and pattern of weights  30  on one side member  14  may be different from the number and pattern of weights  30  on the other side member  14 .