Abstract:
The present inventive compact generator, light emitting wheel hub has an improved light and armature assembly that simplifies manufacturing, improves function and durability of the light emitting wheel hub. The inventive wheel hub is useful for such wheels used in skate board, roller skate, in-line roller skate, wheel chair, and like apparatus.

Description:
STATEMENT REGARDING FEDERAL SPONSORSHIP 
     No invention claimed in this application was made under Federally sponsored research or development. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an improved more reliable light emitting wheel hub for a light emitting wheel and method for making the same. The light emitting wheel is useful for skate board, roller skate, in-line roller skate, wheel chair and like apparatus. The invention additionally provides for greater efficiency in mass production, especially in automated mass production of a light emitting wheel. 
     2. Description of the Related Art 
     There have been a number of attempts to produce a satisfactory light emitting wheel that could be mass produced. In particular, the armature assembly or yoke of the compact generator have been positioned or embedded in the wheel hub of the wheel that rotates around a permanent magnet positioned on the wheel axle of the type shown in U.S. Pat. No. 6,398,395. 
     The patent discloses a compact generator and light emitting wheel. The coil bobbin or spool of the armature assembly of the compact generator is shown in  FIG. 2 . Each lead wire extends from the coil through a respective guide element  145 , which is advantageously a tube. The lead wire is secured at the narrow portion  146  prior to connecting to the light emitting device. The coil bobbin is then combined with an armature cover bearing armature arms to form an armature assembly. A polymer or resin is injection molded around the armature assembly and fixedly incorporated or embedded to form a wheel hub. A conductive plate or printed circuit board bearing light emitting device such as a LED (light emitting diode) is connected to the wheel hub to form a wheel hub assembly and subsequently a wheel tire using resin or polymer such as polyurethane is molded around the wheel hub. 
     Korea Patent Application 10-2000-0086367 published Jul. 12, 2002 shows an improvement on the armature assembly of type shown in U.S. Pat. No. 6,398,395 and is shown in  FIG. 3 . In order to provide a better connection between the lead wires of the coil bobbin, and the light emitting device, lead wire  142   b  is guided from the coil on grooves in block extension  142   a  and connected to conductive pin  142   d  which is subsequently connected to the light emitting device. The lead wires are manually wrapped around respective conductive pins. 
     Korea Patent Application 10-2006-0027308, published Aug. 22, 2007 improved the prior art armature assembly shown in  FIG. 2 , by simplifying the connection of the lead wires and thereby the manufacturing process through a modification of the prior armature assembly and is shown in  FIG. 4 . Lead wires  202  and  206  from coil bobbin  207  protrude outside armature cover  200  and  201  and are manually connected to armature cover extensions  203  and  205 . Armature covers  200  and  201  bear armature arms  204 . Armature extensions connect with a light emitting device, a conductive plate or printed circuit board bearing a LED. This design was prone to frequent lead wire separation or breakage and electrical failure at the contact point with the armature cover extensions during injection molding of the wheel hub. 
     Korea Patent Application 10-2006-0058747, published Jun. 6, 2006 also discloses an improvement of the over the prior art armature assembly shown in  FIG. 2 . As seen in  FIG. 5 , coil bobbin  210  has extensions  212  and  217  where upon lead wires  214  and  215  from the wire coil is secured to prior to injection molding of the wheel hub and manually connecting the lead wires to armature cover extensions  208  and  209  of armature covers  211  and  216 . 
     The above prior art patents employ thin fragile lead wires that are drawn out and away from the coil bobbin outside the armature cover and manually connected to the light emitting device as in the aforementioned US patent or to an extension of the armature cover as in the aforementioned Korea Patent Applications. Wheels incorporating compact generators of US patent and Korea Patent Application were prone to circuit failure in the manufacturing process because of frequent breakage of the lead wire from the coil bobbin during manual manipulation to connect the thin lead wire to the light emitting device or to the conductive pins. 
     The Korea Patent Applications had additional problem of the lead wire separating from the conductive pin or from the armature cover extension during high pressure and temperature injection molding of the wheel hub resulting in loss of conductive contact and electrical failure. This problem is exacerbated because the lead wires are not soldered to the conductive pins or armature cover extensions because of the high temperature and pressure of the injection molding process. 
     The lights of the above prior art wheels were not reliable as the fragile very thin lead wire connecting the conductive pins or posts frequently broke during under stress and shock of hard use or under cold temperatures. This was especially evident when the wheels were used for skates and skate boards. 
     The introduction of air bubbles in the polymer wheel during the cast molding of the polymer tire onto the prior art wheel hub bearing the armature assembly and light emitting device is another problem that frequently occurred, which reduce quality and production efficiency. 
     SUMMARY OF THE INVENTION 
     The presently disclosed invention is an improvement over the compact generator and light emitting wheel of U.S. Pat. No. 6,398,395 which is hereby incorporated by reference in its entirety. The present invention addresses and solves the aforementioned problem creating a much more reliable and durable light emitting wheel. An improved armature assembly wherein the very thin lead wire from the coil bobbin is no longer exposed externally to manufacturing and operational stress and forces that could easily severed the lead wire of the prior art light emitting wheel. The improvement also simplifies the manufacturing process by reducing the number of manual manipulations and allowing for greater automated assembly of the wheel. In an embodiment of the present invention that featured at least two diametrically opposing light emitting devices in the wheel hub, the present inventive coil bobbin allows for operation of at least light emitting device in the event that one light emitting device failed. This embodiment during operation, was capable of producing the appearance (to the human eye) of a continuous line of light at low speeds thus reducing “blinking” light visual effect at low speeds that was problematic of prior art wheels with a single light emitting device. 
     Another improvement is in the structure of a wheel hub portion or cap that covers or overlies the light emitting surface mounted device (SMD), e.g., LED chip mounted on a conductive or printed circuit board (LED-SMD). The improvement allows for bubble free cast molding of the wheel, in particular injection molding a wheel tire of a suitable material such as resin or polymer like polyurethane onto the preformed wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exploded perspective view of the compact generator and wheel of the present invention. 
         FIG. 2  shows a prior art coil bobbin for a compact generator. 
         FIG. 3  shows another prior art another coil bobbin and armature assembly for a compact generator 
         FIG. 4  shows another prior art coil bobbin and armature assembly for a compact generator. 
         FIG. 5  shows a third prior art coil bobbin 
         FIG. 6  is a perspective view of the wire coil bobbin of the present invention. 
         FIG. 7  is a perspective view of one of the armature covers of the present invention. 
         FIG. 8  is a side elevation view of the wheel hub and, light emitting device of the present invention. 
         FIG. 9  is a sectional view taken across a plane shown in  FIG. 8 . 
         FIG. 10  is a perspective view showing the armature assembly and light emitting device. 
         FIG. 11  is a perspective view of the armature assembly and light emitting device. 
         FIG. 12  is a perspective view of the bobbin of the present invention. 
         FIG. 13  is perspective view of a light emitting wheel hub of the present invention. 
         FIG. 14  is a perspective view of another embodiment of the armature cover and coil bobbin. 
         FIG. 15  is perspective view of the 2 opposing section of 4 part armature cover shown in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention solves the above mentioned problem of wire breakage by a new and improved armature assembly or yoke. The problem of air bubble formation during cast molding of the wheel tire was solved by a specially designed wheel hub rim portion. 
       FIG. 1  shows the overall compact generator and wheel. The inventive generator as noted above is an improvement on the generator of US Patent 6,398,395 and operates by basic principles disclosed therein. Wheel  4  has tire  11  which overlies wheel hub  10  containing armature assembly  3 . An electric current is generated when armature assembly  3  revolves around permanent magnet  2  carried on cylindrical element  12 . Element  12  can be, but not necessarily, the type of buffer containing support element for supporting the permanent magnet as disclosed in the aforementioned US Patent. The Fig is shown with wheel bearing  1 , the other opposite wheel bearing  32  is not shown in this Fig. A wheel axle (not shown) passes through the central opening of the wheel bearings and cylindrical element bearing permanent magnet  2 . 
       FIG. 6  shows the present inventive wire coil bobbin  13  of the armature assembly. A thin electrically conductive wire is wound on the bobbin  31  and one lead wire  16  is drawn across one edge  17  of the outward facing of wall  14  and lies along a length to an opposing edge  18  of the outer face of side wall  14  of the bobbin and secured thereto and the other lead wire (not shown) in a similar fashion is drawn of one edge of the outer face of opposite side wall  15  lies along a length across the outer face of opposite side of wall  15  to an opposing edge on the side wall forming the wire coil bobbin  13 . Each lead wire has sufficient length across the outer faces of outer walls  14  and  15  of coil bobbin  13  such that after the wheel hub is injection molded around the armature assembly that electrical contact is substantially maintained along the length of the wire exposed across the outward face of the wall of the wire coil bobbin. This innovation is a critical component of the present invention which avoids and solves the problem of the prior art armature assembly&#39;s exposure of thin wire to stresses and/shock that caused breakage or separation and loss of electrical contact with light emitting device during the manufacturing process and/or during operation of the wheel as mentioned above. This substantially increases the reliability and allows for simpler and more efficient mass production of the light emitting wheel. The bobbin has armature spacers  52  which guide assembly of the armature cover bearing armature arms  5  and maintains proper spacing between the alternating armature arms of armature covers. The spacers are integral part of the bobbin and can be simultaneously molded with molding of the bobbin. This feature facilitates automated or robotic assembly the light emitting wheel. 
     There are two armature covers  19  and  20  and each cover bears at least one electrically conductive extension or post. As shown in the figures, Armature cover  19  has armature arms  5  and electrically conductive extension or post  6  and further can advantageously, if desired, have diametrically positioned electrically conductive extension or post  8 . The opposing, mating armature cover  20  has corresponding armature arms  21 , electrically conductive extension  7  and similarly can advantageously have diametrically positioned electrically conductive extensions  9 . When a second LED-SMD is desired, cover  19  is provided with have diametrically positioned electrically conductive extension or post  8  and cover  20  with corresponding extension or post  9 . The armature arms of one armature cover are positioned such that they alternate with the armature arms of the other armature cover when the armature covers are assembled with wire coil bobbin. The two armature covers at least partially enclose the wire coil bobbin and are sufficiently spaced apart to prevent electrical contact in the final armature assembly and wheel hub. Armature cover with conductive extensions and armature arms can advantageously be a unitary structure formed from a single plate of a suitable material such as steel, which is inexpensive and a readily available material. 
     Wire coil bobbin  13  is placed between the two armature covers  19  and  20  to form an armature assembly as shown in  FIG. 7  and the wheel hub  10  is injection molded with an around it. The ends of the extensions are then connected to the light emitting device, which can be light emitting diode (LED) or any suitable solid state light emitting material or chip surface mounted on a conductive plate or printed circuit board, i.e., a surface mounted light emitting device (SMD) or it can be a bulb type LED. This structural relationship is shown in  FIG. 10 . 
     The one embodiment of the present inventive wheel hub for the armature cover embodiment having diametrically opposed electrically conductive extensions is shown with in  FIG. 8 . The wheel hub has an outer, thinner outer rim portion  22  that is conveniently integrally molded with the thicker main wheel hub body  23 . The lower portion of outer rim portion  22  smoothly and curvingly merges with the upper portion of main body  23 . The wheel hub outer rim portion  22  is embedded in the polymer tire. The wheel hub may optionally have openings  33  and  34 . Electrically conductive extensions  6  and  8  of the armature assembly protrude into gaps  24  and  25 . The gap, which subtends an arc segment of the wheel hub rim, is of sufficient dimension and shape to permit subsequent positioning and connection of the light emitting device  26  to the extensions. The gap in the rim can optionally have shoulder portion  28  that is shaped and dimensioned to receive, guide, mate with the edge and secure transparent or translucent cover or cap  29  to wheel hub. It is noted that the transparent cover over gap  24  is not shown for the purposes of illustrating the structure of the wheel hub. The walls of the gap can optionally have groove or grooves dimension to receive the edges of the light emitting device, which acts to guide and fix or secure the light emitting device, especially a surface mounted light emitting device to wheel hub in the wheel hub gap.  FIG. 9  is a sectional view taken along the sectional plane shown in  FIG. 8 . It shows the relationship of the wire coil  30 , bobbin  31 , permanent magnet ring  2  carried on cylindrical support element  12 . It is noted that bulb type LED may be used instead of the surface mounted LED device shown in the drawings. 
     Transparent or translucent cover  29  for the light emitting device of the present invention is shaped and dimensioned to cover gap  25  and smoothly conform and merge with the shape of the wheel hub rim. The transparent or translucent cover protects the light emitting device  26  and  36  and electrical connection with the armature assembly extensions during cast molding of the wheel tire onto the hub. The structural relationship of the light emitting device and the armature assembly is shown in  FIG. 10 . 
     It was found that if the transparent cover extended and protruded over wheel hub rim, air either escaping from the gap space in the wheel hub or trapped on the surface that resulted in undesirable formation of air bubbles during cast molding the tire onto the wheel hub. The present inventive cover because of its shape eliminates the formation air bubbles during the cast molding of the tire onto the wheel hub. One embodiment of the transparent or translucent cover is shown in  FIG. 11 . In this embodiment the cap have edge extensions  35  that conform and smoothly merge with opposing surface of the main wheel hub body  23 . 
     The light emitting device can be a surface mounted device such as an arrangement of three LED chips  27  on a conductive plate as shown. The LED configuration may be 3 staggered from top to bottom as shown in  FIG. 8  or a row of two and one below. The color of the light emitting device or LEDs can be any desired color or color combinations. A very useful and advantageous and non-limiting example of a combination is the use of three color LED chip mounted SMD. Blue and green LED chips positioned in the outer portion in a row above the green LED chip achieves an unexpected visual effect of being able to see each color separately without the colors blending together as the wheel rotates in use. More than 3 LED chips or bulbs as well as their arrangement can be used in the present invention. As noted previously, LED bulb type can be used instead. 
     The use of two opposed LED-SMD in the wheel hub such as shown in  FIGS. 8 and 10  advantageously reduces the lead time such that the light from the LED appears to be continuous at lower rpm instead of being intermittent or blinking if only one LED-SMD were used. This is especially advantageous in terms of safety when the wheel hub is used for a larger wheel of a wheel chair. 
       FIG. 13  shows another embodiment of the inventive light emitting wheel hub. The transparent cover spans across the top outer portion of the wheel hub  41 . The gap is of a has a width that substantially spans the width of the top portion of the wheel hub depth that would accept the thickness of a substantially planar transparent cover (unlike the cover  29  of the previous embodiment). One end walls  40  of the gap shows a depth to accommodate the thickness of the cover. The cover overlies light emitting device comprised of LEDs  37 ,  38  and  39  carried on conductive plate or printed circuit board  42 . Armature cover extension  6  and  7  are in electrical contact with board  42 . There is a plurality of cross members  43  that guide and support the light emitting device. As before the outer surface of the transparent cover merges with and smoothly conforms to the shape and profile of the wheel. 
     The diameter of wheel hub can be small as approximately 40 mm, making this wheel hub configuration useful for small wheel diameter such as those used in roller skates, skate boards and aggressive skate wheels. 
       FIGS. 14 and 15  illustrates a further embodiment of an armature cover according to the present invention. It is a  4  part armature cover.  FIGS. 14 and 15  shows two of the four section or part armature cover: top armature cover portion  44  with conductive extension or post  45  and cooperating lower armature cover portion  46  with conductive extension or post  47 . Armature covers  44  and  46  bear armature arms  50  and  51 , respectively. The other two armature cover portions have not been shown in order to better illustrate the structure but would be similar to the two shown and have appropriate conductive extension or post to create a one or more LED-SMD in the wheel hub. The use of  4  part armature cover had an unexpected benefit in improving the manufacture of the wheel hub and reliability. There was better and more consistent electrical contact was formed between the coil bobbin when the armature cover was pressed against the lead wire on the outside wall of coil bobbin during plastic injection molding of the wheel hub around armature cover and coil bobbin. 
     The use of LED chip mounted SMD provided a distinct advantage over LED bulb as it emitted more uniform light in all directions whereas the LED bulb was more directional in the intensity, i.e., it was brighter from the side of the bulb than from top of the bulb. Thus, when the wheel bearing the LED-SMD rotates during use, the intensity and color is substantially uniformly visible from the side and front of the wheel. 
     The manufacturing process of the light emitting wheel is greatly simplified over the prior art. The conductive wire coil bobbin is simply positioned between the two armature covers and the wheel hub is injection molded with a suitable plastic or polymer, which can be opaque, around the armature assembly. The high pressure of the injection molding process presses the armature cover against the copper wire lying across the outer face of the coil bobbin to create an electrical contact area that is substantially length of the wire lying on the face of the coil bobbin. The light emitting device is connected to the ends of the conductive extensions that protrude from the open gap, such as by soldering and the transparent or translucent cover for the light emitting device is placed over the gap and sealed to the wheel hub rim prior to cast molding a transparent or translucent polymer tire onto a portion of the wheel hub that supports the tire. The polymer may be conveniently a urethane polymer or resin. This can be all done by automation or robotic means. 
     It is understood that various modifications and variations of the present inventions such as material of construction and arrangement of light emitting devices, electrical and magnetic material and elements are within the purview of the present invention.