Abstract:
A roller skate having enhanced steerability and stability is disclosed. The skate includes a platform for supporting a skater&#39;s foot and front and rear wheel trucks secured to the underside of the platform. A pair of front wheels is rotatably mounted in transverse axial alignment on the front wheel truck and a pair of rear wheels is rotatably mounted in transverse axial alignment on said rear wheel truck. The pairs of front and rear wheels are also in parallel axial alignment with each other and mounted on their respective wheel trucks for resiliently controlled, tilting movement about downwardly inclined longitudinal axis. In addition, a fifth wheel is rotatably mounted on the front wheel truck between the pairs of front and rear wheels and in parallel axial alignment with the wheel pairs. An additional preferred roller skate includes a single wheel rotatably mounted to the front toe plate. The front wheel is not tiltable about the skate&#39;s longitudinal axis. This roller skate includes three wheels rotatably mounted to a rear wheel truck. The rear wheel truck is mounted to the skate&#39;s heel plate by a pivot mount allowing the three rear wheels to pivot about the skate&#39;s transverse axis which also allows a rear center wheel to engage a brake pad. Moreover, the rear wheel truck is mounted to the heel plate for providing tilting movement at least partially about the skate&#39;s longitudinal axis to permit turning.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part application of U.S. patent application Ser. No. 11/581,242, filed on Oct. 16, 2005, now U.S. Pat. No. 7,618,046 issued Nov. 17, 2009, which in turn is a divisional application of U.S. patent application Ser. No. 10/923,222, filed on Aug. 20, 2004, now U.S. Pat. No. 7,121,561 issued Oct. 17, 2006, which in turn, is a continuation application claiming the benefit under 35 USC 119(e) of U.S. provisional application Ser. No. 60/497,884, filed on Aug. 25, 2003 and U.S. provisional application Ser. No. 60/537,273, filed on Jan. 16, 2004. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to wheeled skates and more particularly to wheeled skates adapted to be removably mounted on a skater&#39;s footwear. The invention further relates to wheel trucks for mounting wheels on skates, skate boards, scooters and the like. 
       PRIOR ART 
       [0003]    U.S. Pat. No. 4,351,538 shows an expandable roller skate with toe and heel plates and toe and instep straps for securing the skate on a skater&#39;s shoe. 
         [0004]    U.S. Pat. No. 1,771,855 shows an expandable strap-on roller skate with wheels positioned in front of the toe plate and in back of the heel plate. 
         [0005]    U.S. Pat. No. 5,620,190 shows an expandable strap-on skate with front and rear brake pads. 
         [0006]    U.S. Pat. No. 6,217,039 shows an expandable strap-on skate with buckles for securing the straps. 
         [0007]    U.S. Pat. No. 5,551,713 shows a skate with a pair of rear wheels and two in-line front wheels and front and rear stops or brakes. 
         [0008]    U.S. Published Patent Application No. 2003/0116930 discloses a roller skate having a tiltable pair of front wheels and a single rear wheel. 
         [0009]    In addition, a search for information related to the present invention uncovered 
         [0010]    the following documents: U.S. Pat. Nos. 6,481,726; 6,431,559; 6,209,889; 5,826,895; 5,224,718; 4,572,529; 4,382,605; 4,272,090; 1,975,905; 1,809,612; 1,609,612; 1,271,891 and 177,566 and U.S. Published Patent Application Nos. 2003/0057670; 2003/0057665; 2003/0052463 and 2002/0030332. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides a roller skate which is adapted to be strapped onto or removably mounted on a skater&#39;s street shoe, sneaker or the like. In its broadest sense, the roller skate includes a platform for supporting a skater&#39;s foot and front and rear wheel trucks which are mounted on the underside of the platform. The front wheel truck includes a pair of front wheels rotatably mounted on the front wheel truck in transverse axial alignment relative to the longitudinal direction of the platform. The rear wheel truck also preferably includes a pair of rear wheels (although one wheel will also work as described in more detail infra) which are also rotatably mounted on the rear wheel truck in transverse axial alignment. The pairs of front and rear wheels are also in parallel axial alignment with each other. In addition, a fifth but single (i.e. not paired) center wheel is provided which is rotatably mounted between the pairs of front and rear wheels and in parallel axial alignment with said pairs of wheels. 
         [0012]    In a preferred embodiment, the pair of front wheels is mounted on its respective wheel truck, i.e. the front wheel truck, for tilting or pivotal movement about a longitudinal axis, preferably a downwardly inclined longitudinal axis. A damping pad is provided which is mounted on the front wheel truck for resiliently controlling the tilting of the pair of front wheels about the longitudinal axis. In addition, the fifth but single center wheel is rotatably mounted on the front wheel truck. This preferred embodiment is advantageous in that it enhances the skater&#39;s ability to steer the skate and also enables the skater to generate more power with each thrust of the skate. 
         [0013]    In an even more preferred embodiment, the pair of rear wheels is also made tiltable or pivotal about a longitudinal axis, preferably a downwardly inclined longitudinal axis. Tilting of the rear wheels further enhances the skater&#39;s ability to steer since the rear wheels not only tilt when the skater initiates a turn but do so in a direction opposite that of the front wheels which makes it even easier for a skater to execute a turn, particularly a quick turn. The rear wheel truck also includes a damping pad for resiliently controlling the tilting of the pair of rear wheels about the longitudinal axis. A four wheeled skate with only one rear wheel is also described as is a three wheeled skate which does not utilize the center wheel. 
         [0014]    In still an additional preferred embodiment, the roller skate includes a front truck upon which is rotatably mounted a single center wheel. Preferably, the center wheel is not made to be tiltable, or in other words pivotable, about the skate&#39;s longitudinal axis. For this embodiment, the skate may, or may not, include a damping pad for damping vibration to the front center wheel. Preferably, this embodiment includes a rear truck upon which are rotatably mounted at least two rear wheels positioned side by side to form a pair of parallel rear wheels. More preferably, three wheels are mounted to the rear wheel truck including the pair of parallel rear wheels as well as an additional single center wheel positioned rearwardly of the pair of wheels. Preferably, the rear wheel truck is mounted to the underside of the platform so as to be at least partially tiltable, or in other words pivotable, about the skate&#39;s longitudinal axis. Preferably, the rear wheel truck is mounted to the platform to allow the three rear wheels to tilt about an inclined longitudinal axis relative to the platform. This tilting movement of the three rear wheels is provided for allowing the three rear wheels, and in turn the skate, to turn left or right as a skater adjusts their weight to cause the platform to tilt relative to the three rear wheels. 
         [0015]    In still an additional preferred embodiment, the skate includes a pivot mount for mounting a wheel truck to the underside of the skate platform. Preferably, the pivot mount is provided for mounting the rear wheel truck to the rear underside of the platform. The pivot mount allows the wheel truck to pivot about the skate&#39;s transverse axis. For this embodiment, it is preferred that the roller skate include a brake having a brake pad positioned above the rear center wheel so as to engage the rear center wheel when the platform is pivoted rearwardly relative to the three rear wheels so that the brake pad engages and restricts rotation of the rear center wheel. Advantageously, the pivot mount construction and positioning of the brake pad to engage the rear center wheel allows the three rear wheels to maintain engagement with the ground even as the platform is tilted rearwardly during braking. 
         [0016]    The above summary describes preferred forms of the present invention and is not in any way to be construed as limiting the claimed invention to the preferred forms. 
     
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
         [0017]    The invention will be more readily understood by reference to the accompanying drawings wherein like reference numerals indicate like elements, and in which: 
           [0018]      FIG. 1  is a top front perspective view of a roller skate embodying the present invention; 
           [0019]      FIG. 2  is a top plan view thereof; 
           [0020]      FIG. 3  is a bottom plan view thereof; 
           [0021]      FIG. 4  is a side elevation view thereof; 
           [0022]      FIG. 5  is a front elevation view thereof taken substantially in the plane of line  5 - 5  on  FIG. 4 ; 
           [0023]      FIG. 6  is a rear elevation view thereof taken substantially in the plane of line  6 - 6  on  FIG. 4 ; 
           [0024]      FIG. 7  is a section view taken substantially in the plane of line  7 - 7  on  FIG. 4 ; 
           [0025]      FIG. 8  is a section view taken substantially in the plane of line  8 - 8  on  FIG. 5 ; 
           [0026]      FIG. 9  is an upside-down perspective exploded view of the front wheel truck of the skate embodying the present invention; 
           [0027]      FIG. 10  is an upside-down perspective exploded view of the rear wheel truck of the skate embodying the present invention; 
           [0028]      FIG. 11  is a bottom plan view of an embodiment of the present invention which is similar to that of  FIG. 1  but which has only one rear wheel; 
           [0029]      FIG. 12  is a side elevation view of the skate of  FIG. 11 ; 
           [0030]      FIG. 13  is a rear perspective view of a preferred roller skate including a single wheel mounted to the front truck and three wheels mounted to the rear truck; 
           [0031]      FIG. 14  is a side view of the roller skate illustrated in  FIG. 13 ; 
           [0032]      FIG. 15  is a side view of the roller skate shown in  FIGS. 13 and 14  wherein the platform is tilted rearwardly relative to the rear wheels; 
           [0033]      FIG. 16  is a perspective view illustrating an additional embodiment of a roller skate including a single wheel mounted to the skate&#39;s front truck and three wheels mounted to the skate&#39;s rear truck; 
           [0034]      FIG. 17  is a bottom perspective view illustrating the rear truck assembly for the roller skate shown in  FIG. 16 ; 
           [0035]      FIG. 18  is a rear elevation view of the roller skate shown in  FIGS. 16 and 17 ; and 
           [0036]      FIG. 19  is a rear elevation view of the roller skate shown in  FIG. 18  wherein the rear wheel truck is mounted to the platform for providing tilting movement of the three rear wheels about an inclined longitudinal axis relative to the platform. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    The present invention is embodied in a roller skate  20  and particularly in a skate of the type adapted to be strapped on to or removably mounted on a skater&#39;s street shoe, sneaker or the like. The roller skate is basically a four wheel or quad type roller skate with four wheels  21  arranged in a quadrangle, but includes a fifth wheel  22  for assisting in pushing to propel the skater, and to improve the skater&#39;s balance. The skate includes front wheel trucks  24  and rear wheel trucks  25  that, while finding particular utility on a roller skate, are also adaptable for use on skate boards, scooters and the like (not shown). While the invention is described herein in the context of a strap-on roller skate, it is also applicable to boot mounted skates. 
         [0038]    The skate includes a longitudinally adjustable platform  26  formed of a toe plate  28  and a heel plate  29  coupled to the toe plate by a telescoping platform length adjuster  30  so that the length of the skate platform  26  can be adjusted to fit a skater&#39;s foot and shoe. In order to prevent the skater&#39;s foot from slipping relative to the toe and heel plates  28 ,  29 , the upper surface of the plates includes rows of teeth or barbs  31 . An upstanding heel panel or cup  32  is provided for engaging the skater&#39;s heel and preventing it from slipping from the heel plate  29 . 
         [0039]    A front quick clamp releasable strap  34  is secured to upstanding strap bosses  35  on opposite sides of the toe plate  28  and adapted to engage and secure the users foot to the skate toe plate. A similar quick connect releasable strap  36  is secured to upstanding strap bosses  37  on the heel plate  29  and adapted to pass over the skater&#39;s instep for securing the skaters foot and heel to the heel plate  29 . The straps are of the type well-known for securing bindings of skates, snow boards and skis. 
         [0040]    The front wheel truck  24  is secured to the underside of the toe plate  28  and the rear wheel truck  25  is secured to the underside of the heel plate  29 . To assist the skater in stopping, a front brake  39  is mounted on the toe plate  28  and a rear brake  40  is mounted on the heel plate  29 . 
         [0041]    The front wheel truck  24  is formed by an L-shaped mounting bracket  42  ( FIGS. 8 ,  9 ) having a horizontal plate  43  adapted to be secured to the underside of the toe plate  28  and a depending vertical plate  44  integral with the horizontal plate  43  and defining on its inner face  45  a convex spherical bearing surface  46 . The horizontal plate  43  is secured to the underside of the toe plate  28  for pivotal movement about a transverse axis which is generally perpendicular to the longitudinal axis of the platform  26  by a pair of mounting pins  48  attached at one end to the horizontal plate  43  of the mounting bracket by machine screws  49  and having eyelets  50  at their other end extending through vertical elongated slots  51  defined in spaced apart corresponding segmentally shaped ribs  52  on the underside of the toe plate  28 , the slots  51  opening through the upper surface of the toe plate  28 . The eyelets  50  receive mounting pins  54  extending laterally through the ribs and secured to the eyelets  50  by setscrews  55  extending through the upper edge of the eyelet  50  and accessible through the openings of the slots  51  in the toe plate. Pins  54  which, as indicated, are received in eyelets  50  allow plate  43  to pivot about an axis defined by pins  54  which is transverse to the platform&#39;s longitudinal axis. 
         [0042]    The mounting ribs  52  as shown in  FIG. 4  also define convexly curved outer surfaces  58 , and the horizontal plate  43  of the L-shaped front mounting bracket  42  defines corresponding concavely curved surfaces  59  adapted to receive arcuate resilient damping pads or cushions  60  which provide shock absorbing, vertical cushioning of the wheel mounting on the skate plate. As will be appreciated, the shock absorbing, resilient pad is engaged to absorb shock when plate  43  of the wheel truck is pivoted in either direction about the transverse axis defined by pins  54 . This type of pivoting action could occur if, for example, the skater is skating on rough terrain or encounters an obstruction such as rock or twig. 
         [0043]    For mounting a pair of front wheels  21  on the front truck  24  in tiltable relation to the toe plate  28 , a wheel axle yoke  61  is pivotally secured to the vertical plate  44  of the L-shaped mounting bracket  42  by a pivot pin  62 . The wheel axle yoke  61  is formed by a central web portion  64  and opposed arms  65  extending from the sides thereof. The side arms  65  include apertures  66  therein mounting bushings  68  through which axle pins  69  extend and are secured by machine bolts  70 . The wheels  21 , which may have internal bearings  71  are mounted and supported on the axles defined by the pins  69 . The yoke  61  is pivotally mounted on the vertical plate  44  of the front mounting bracket  42 . To this end, the yoke web  64  defines a concave spherical bearing surface  72  corresponding to and receiving the convex spherical surface  46  on the vertical mounting plate  44 . The pivot pin  62  extends through corresponding apertures  75 ,  76  respectively in the bracket plate  44  and yoke web  64 . The apertures  75 ,  76  and pivot pin  62  are aligned along an axis  78  ( FIG. 8 ) that is inclined at an acute angle downwardly and rearwardly with respect to the horizontal plane of the toe plate  28 . The inclined pivot axis  78  and spherical bearing surfaces  46 ,  72  enable the wheels  21  to tilt (i.e. pivot about the axis) and turn when the skater leans one way or the other. The tilting movement is limited and controlled by a resilient U-shaped damping pad  79  mounted in a slot  80  in the horizontal plate  43  of the bracket, into which extends a tang  81  integral with the web of the wheel yoke  61 . By varying the hardness and resiliency, conventionally expressed as the durometer of the material, of the resilient damping pad  79 , the swinging motion of the yoke  61  and pair of front wheels  21  can be controlled to suit the skater. 
         [0044]    For providing stability to the skate, and to assist the skater in pushing with one skate or the other to increase the speed of skating, a fixed axis, and preferably non-tilting, third front wheel  22  (fifth wheel overall) is supported beneath the toe plate  28  between mounting arms  84  extending rearwardly from the horizontal plate  43  of the mounting bracket  42 . The wheel  22  is rotatably supported on an axle pin  85  and can move vertically with the mounting bracket  42  but does not swing or tilt. The axle pin  85  is secured between the arms  84  by a machine screw  86 . The wheel  22  provides stability to the front skate truck and skate when the skater is turning or pushing. 
         [0045]    The rear wheel truck  25  is somewhat similar in construction to the front wheel truck  24  and includes an L-shaped rear mounting bracket  88  having a horizontal plate  89  adapted to be secured to the underside of the heel plate  29  and a depending vertical plate  90  integral with the horizontal plate  89  and defining on its inner face  91  a convex spherical bearing surface  92  ( FIGS. 8 and 10 ). A pair of mounting arms  94  extend from the sides of the horizontal plate  89  and are pivotally engaged with bosses  95  projecting from the underside of the heel plate  29  by pivot machine screws  96 . The horizontal plate  89  is further secured to the underside of the heel plate  29  by a pair of mounting pins  98  attached at one end to the horizontal plate  89  of the mounting bracket  88  by machine screws  99  and having eyelets  100  at their other end extending through vertical elongated slots  101  defined in spaced apart corresponding segmentally shaped ribs  102  on the underside of the heel plate  29 , the slots  101  opening through the upper surface of the heel plate  29 . The eyelets  100  receive mounting pins  104  secured to the eyelets by setscrews  105  extending through the upper edge of the eyelet  100  and accessible through the openings of the slots  101  in the heel plate  29 . The mounting ribs  102  define convexly curved outer surfaces  107 , and the horizontal plate  89  of the L-shaped rear bracket  88  defines corresponding concavely curved surfaces  108  adapted to receive arcuate, resilient damping pads or cushions  109  which provide shock absorbing, for vertical cushioning of the wheel mounting on the skate plate as discussed above with respect to the front wheel truck. 
         [0046]    A wheel axle yoke  110  similar to that described above is provided for mounting a pair of rear wheels  21  on the mounting bracket  88  for swinging or tilting movement about an inclined axis. The wheel axle yoke  110  is formed by a central web  111  and opposed side arms  112  extending therefrom. The side arms  112  include apertures  114  mounting bushings  115  through which axle pins  116  extended and are secured by machine bolts  118 . The wheels  21  which may have internal bearings  119  are mounted and supported on the axle pins  116 . The yoke  110  is pivotally mounted on the vertical plate  90  of the rear mounting bracket  88 . To this end, the yoke web  111  defines a concave spherical bearing surface  120  corresponding to and receiving the convex spherical surface  92  on the vertical mounting plate  90 . A pivot pin  121  extends through corresponding apertures  122 ,  123  respectively in the bracket plate  90  and yoke web  111 . The apertures  122 ,  123  and pivot pin  121  are aligned along an axis that is along an axis  124  that is inclined at an acute angle downwardly and forwardly with respect to the horizontal plane of the heel plate  29 . The inclined pivot axis  124  and spherical bearing surfaces  92 ,  120  enable the wheels to tilt and turn when the skater leans one way or the other. The tilting movement is limited and controlled by a resilient U-shaped damping pad  125  mounted in a slot  126  in the horizontal plate  89  of the bracket, into which extends a tang  128  integral with the web of the rear wheel yoke  110 . By varying the hardness and resiliency of the resilient damping pad  125 , the swinging motion of the yoke and pair of rear wheels  21  can be controlled to suit the skater. The mounting plate and wheel yoke positions the rear pair of wheels slightly in back of the heel plate and thus in back of the skater&#39;s heel as shown in  FIG. 4 . This configuration enhances the skater&#39;s balance as well as making it easier to use the rear brake  40 . 
         [0047]    On both the front truck and the rear truck the mating surfaces between the wheel yoke and the vertical plate of the mounting bracket are spherical as described above. The mating surface of each corresponding mounting bracket plate is convex while the mating surface of each wheel yoke is concave. This configuration is similar to a ball and socket joint and allows the wheel yoke to pivot or rotate relative to the mounting bracket about the axis of rotation defined by the mounting pin. Both the axis of swivel  78  of the front pair of wheels and the axis of swivel  124  of the rear pair of wheels being longitudinal and at a downwardly acute angle with respect to the plane of the toe plate and heel plate allows the wheel pairs to tilt and turn as the skater leans to one side or the other, thereby providing a steering effect for skating on a curve or arc. If, for example, the skater leans to the left in order to turn along an arc to the left, the front pair of wheels pivot to the left while the rear pair of wheels pivot towards the right, thereby providing steering towards the left. Likewise, the same steering effect is obtained when the skater leans to the right in order to turn towards the right. In either case, the third wheel on the front truck does not pivot, thus providing stability during a turn in either direction, as well as during pushing by the skater using the side wheels to increase the speed of skating. 
         [0048]    The wheels  21  are preferably of the type typically used in in-line skates which are formed of wear resistant polyurethane or other suitable plastic material affording durability and a long life. In line skate type wheels are preferred because they have a generally oval shaped cross-section when the cross-section includes or is taken along the wheel&#39;s rotational axis as shown in  FIG. 7 . The oval shape is preferred since it has a rounded tread surface which makes it easier for a skater to execute a turn. Conventional four wheeled roller skates typically have flat tread surfaces which make it more difficult for a skater to execute a turn since a skater using flat wheels cannot lean as much into a turn as a skater can with wheels having more rounded tread. 
         [0049]    The front brake  39  consists of a brake pad  129  mounted on a brake bracket  130  secured to the underside of the toe plate. The rear brake  40  likewise includes a brake pad  131  secured to a bracket  132  mounted on the upstanding heel flange  32  at the rear of the heel plate. The flange  32  further serves as a heel stop engaging the heel of a skater&#39;s shoe. 
         [0050]    The telescoping extension mechanism  30  enabling the toe plate  28  and heel plate  29  to be longitudinally adjusted relative to each other is formed by an elongated bar  135 , cross-shaped in cross section, secured to the underside of the heel plate  29  and extending toward the toe plate  28 , and a pair of elongated channels  136  secured to the toe plate with the channels facing each other as shown in  FIG. 5 . The bar  135  defines laterally projecting ribs  137  that are engaged in the channels  136  secured to the toe plate, thereby providing for telescoping adjustment. When the length adjustment of the toe and heel plates has been determined, the bar and channels are secured by the machine screws  96  utilized to mount the truck on the underside of the heel plate. The screws can be tightened or released to engage the channels and rod, thereby fixing the desired length of the skate. In addition, the skate structure is preferably formed of lightweight plastic or metal such as aluminum. 
         [0051]    Skaters propel themselves on the skates by placing body weight on one skate and using the inside side wheels of the other skate to push. Because the skate wheels are pivotally mounted they tend to turn as the skater uses one skate to push. The third wheel at the front of the pushing skate provides stability and enables the skater to obtain a strong push or thrust. The third wheel on the front truck also affords stability to the skater during forward or backward skating, as well as when skating on uneven surfaces such as sidewalks, trails, and over sticks and stones. 
         [0052]      FIGS. 11 and 12  illustrate a four wheeled roller skate  220  of the present invention which differs from skate  20  of the first embodiment in that it is only provided with one rear wheel  221  instead of the pair of rear wheels  21  illustrated in  FIG. 3 . As best shown in  FIG. 11 , rear wheel  221  is in line with the single center wheel  22  such that they both rotate in the same plane. Bracket  232  for rear brake  40  is also shaped differently than the bracket  132  for brake  40  of the first embodiment to prevent rear wheel  221  from contacting it wheel  221  should move upwardly due to the compression of pad  109  which could occur if a bump in the terrain were encountered. Rear truck  225  of this embodiment also differs from truck  25  of the first embodiment in that it only needs structure (not numbered) for mounting one wheel, i.e. wheel  221 , not the pair of wheels  21  mounted on rear truck  25 . The remaining components of skate  220  are identical to those of skate  20  and thus are numbered the same. Skate  220  does not offer quite the stability of that provided by skate  20  but it is more maneuverable and lighter because it utilizes only one rear wheel. 
         [0053]    The present invention also make possible a three wheeled skate (not shown) which would be similar to skate  220  but would not utilize center wheel  22 , i.e. center wheel  22  would be removed from the skate. This skate would not be as stable as either skates  20  or  220  but it would be lightweight and very maneuverable. This skate would also not enable the skater to generate quite as much thrust as is possible with skates  20 ,  220  since the ability to push off the three wheel combination of the two front wheels  21  and the single center wheel  22  is what is believed to enable the generation of high thrust in the illustrated embodiments. 
         [0054]      FIGS. 13-18  illustrate a four wheeled roller skate of the present invention. The roller skate  20  includes a platform  26  which is preferably longitudinally adjustable including a toe plate  28  and a heel plate  29  connected by a telescoping section  30 . Preferably, the roller skate includes straps  34  for engaging a skater&#39;s foot and preventing it from slipping from the platform  26 . Though not shown in the drawings, preferably the straps  34  are self adjusting so as to automatically tighten upon a persons foot. The automatic tightening of the straps may be accomplished utilizing springs, elastic bands or the like. 
         [0055]    The front wheel truck  24  is affixed to the underside of the toe plate  28  while the rear wheel truck  25  is affixed to the underside of the platform&#39;s heel plate  29 . For this embodiment, the roller skate  20  includes a single front wheel  21  rotatably mounted to the front wheel truck  24 . As illustrated in  FIGS. 14-17 , preferably the front wheel  21  is mounted to the front truck  24  by an L-shaped mounting bracket. For this embodiment, the front truck  24  is constructed so as to not provide the front wheel with tilting, or in other words pivotal movement, about the platform&#39;s longitudinal axis. 
         [0056]    For the embodiment illustrated in  FIGS. 14-18 , the roller skate  20  includes three rear wheels  20  rotatably mounted to the rear wheel truck  25 . The three rear wheels include a pair of parallel wheels  21  and a center wheel  21  positioned rearward of the pair of parallel wheels. The three rear wheels  21  are mounted on the rear truck by a wheel axle yoke  61  similar to that described above for permitting swinging or tilting movement of the rear wheels  21  about an inclined longitudinal axis relative to the skate&#39;s platform  26 . The wheel axle yoke  61  is again formed to include side arms  65  extending from a central web  64 . The side arms  65  include holes through which axle pins  69  extend for rotatably mounting the wheels  21 . In turn, the yoke  61  is affixed to a mounting plate by a pivot pin  62 . The pivot pin  62  defines an axis that is inclined at an acute angle downwardly and rearwardly with respect to the horizontal plane of the skate&#39;s platform. The incline axis enables the rear wheels to tilt and turn when the skater leans one way or the other. Preferably, the rear wheel truck is constructed so as to place the pair of side-by-side parallel wheels below the skater&#39;s heel while the third central wheel is positioned rearward of the skater&#39;s heel. 
         [0057]    As illustrated in  FIGS. 14-16 , in a preferred embodiment the roller skate  20  includes a pivot mount  140  for mounting the rear wheel truck  25  to the heel plate  29 . The pivot mount  140  allows the rear truck  25  and corresponding three rear wheels  21  to pivot about a transverse axis defined by pivot pin  141 . As illustrated in  FIG. 15 , the pivot mount  140  allows a skater to tilt their foot rearwardly so as to maintain the rear wheels on the ground while lifting the front wheel from the ground. Preferably, the skate includes a rear brake  40 . The rear brake  40  includes a bracket projecting from the rear of the heel plate  29  and a brake pad  41 . The brake pad  41  is positioned so as to selectively engage and disengage as the skater&#39;s heel is tilted rearwardly and forwardly, respectively. Advantageously, this embodiment allows the skater to maintain the three rear wheels upon the ground even during braking. 
         [0058]    While several particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Therefore, it is not intended that the invention be limited except by the following claims. Having described my invention in such terms so as to enable persons skilled in the art to understand the invention, recreate the invention and practice it, and having presently identified the presently preferred embodiments thereof, we claim: