Abstract:
A remotely controlled toy vehicle appears to drift when turning, appearing to slide into the turn, by having a rear driving platform that swivels under a main body of a chassis. In addition to making the chassis appear to slide, the rear driving platform induces a tilt of the chassis into the turn, simulating a car suspension shifting toward the slide. Dummy rear wheels attached to pivoting trailing arms assist in obscuring the rear driving platform and make the toy vehicle appear more realistic. Castoring front wheels further enhance the drifting effect.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application claims the benefit of U.S. Provisional Application Ser. No. 60/515,989, entitled “DRIFTING RADIO CONTROLLED TOY VEHICLE”, filed on 31 Oct. 2003. 

   FIELD OF THE INVENTION 
   The present invention relates to motorized toy wheeled vehicles and more particularly to remotely controlled toy vehicles capable of performing trick maneuvers. 
   BACKGROUND OF THE INVENTION 
   Remotely controlled (RC) toy vehicles are a perennial favorite among children and adults. Those that are capable of performing trick maneuvers are particularly desired. One such maneuver is “drifting”, a term possibly borrowed from snowboarding slang wherein the snowboard slides sideways with respect to the longitudinal axis of the board. Drifting is a word that describes a car sliding through a turn; it has been around since early car races in the late 1800&#39;s. In RC toy vehicles, expert drivers attempt to simulate racing maneuvers such as power slides or drifting as a way of rounding a sharp turn quickly. Typically, causing a wheeled toy vehicle to power slide or drift is exceedingly difficult to achieve. Without momentum and reduced frictional contact to the undersurface, the wheeled toy vehicle will merely turn and not slide. Even if able to initiate a slide, the wheeled toy vehicle may tend to lose control, spinning or tumbling, rather than remaining in a drifting orientation maintaining a relatively stable sliding angle. Thus, generally known toy vehicles are not designed to drift, especially if used in a variety of surface conditions, including soil, asphalt, carpeting, hardwood flooring, etc. 
   Consequently, a significant need exists for a toy vehicle that is capable of drifting, appearing to slide to the side. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention overcomes the above-noted and other deficiencies of the prior art by providing a toy vehicle that appears to drift when turned regardless of surface conditions. Moreover, this maneuver does not require an expert to control the vehicle to achieve this look. A rear driving platform swivels with respect to a chassis of a toy vehicle as paired front wheels castor. Thus, when initiating a turn by swiveling, the rear driving platform causes a rear portion of the chassis to drive into the turn with a front portion of the chassis responding with the pair of front wheels castoring in the direction of the turn. Thus, the toy vehicle appears to drift. Since the rear driving platform advantageously remains in control without sliding upon the surface, this drifting maneuver is achieved without limitations of the speed of the toy vehicle being sufficiently high or that the frictional contact of the rear wheels with the underlying surface being sufficiently low. In addition, body roll accentuates the look of drifting. 
   These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a toy vehicle with its paired castor front wheels and rear drive platform longitudinally aligned for straight-ahead movement and with a battery box omitted to expose swivel centering. 
       FIG. 2  is a top view of the toy vehicle of  FIG. 1  with a main body and rear driving platform shown in phantom and with the battery box exploded to expose a swivel mechanism. 
       FIG. 3  is a perspective, exploded view of the toy vehicle of  FIG. 1 . 
       FIG. 4  is a rear view in elevation of the toy vehicle of  FIG. 1 . 
       FIG. 5  is a left side view in elevation of the toy vehicle of  FIG. 1 . 
       FIG. 6  is a perspective view of the toy vehicle of  FIG. 1  with its rear driving platform swiveled to the left and its paired front wheels castoring to the right. 
       FIG. 7  is a rear perspective view of the toy vehicle of  FIG. 6 . 
       FIG. 8  is a rear view in elevation of the toy vehicle of  FIG. 6 . 
       FIG. 9  is a top view of the toy vehicle of  FIG. 6 . 
       FIG. 10  is a block diagram of a remote control system for the toy vehicle of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning to the Drawings, wherein like numerals denote like components throughout the several views, in  FIGS. 1-5 , a toy vehicle  10  includes a three-part chassis  12  that is pivotally coupled in order to simulate a drifting maneuver. A main body  14  and a front portion  16  of the chassis  12  appear to be drifting while a rear drive platform  18  that swivels under the main body  14  provides the impetus for the steering by drifting while remaining largely unobserved. The drifting effect is enhanced by having the chassis  12  appear to lean into the turn. Thus, the lean simulates a car suspension being compressed on the turn side of the chassis in response to the sliding contact of a paired front left and right wheels  20 ,  22  and two paired rear left and right dummy wheels  24 ,  26  attempting to overcome the sliding momentum of the chassis  12 . The effect is further enhanced by a vehicle body (not shown) that would hide the components depicted, except for the front wheels  20 ,  22  and rear dummy wheels  24 , 26 . 
   In particular, the rear drive platform  18  swivels about a swivel Axis A that is tipped slightly forward from an otherwise vertical axis, assuming that the toy vehicle  10  rests upon a horizontal surface. The main body  14  is perpendicular to Axis A and level left to right when the rear drive platform  18  is longitudinally aligned, as in  FIG. 1 . The rear driving platform  18  is supported by paired left and right drive wheels  28 , 30  connected to one another by a drive axle  32  that spins about an Axis B, which is horizontal. 
   With particular reference to  FIGS. 2-3 , the rear driving platform  18  includes a spindle table  34  aligned with Axis A that is rotatingly received through a guide  36  formed in the main body  14 . A recessed arc surface  38  along an aft portion of the main body  14  receives an upwardly projecting limit block  40  formed in the rear driving platform  18 , thus limiting the swivel of the rear driving platform  18 . Since the drive wheels  28 ,  30  remain horizontal as the rear driving platform  18  swivels, the Axis A defined by the swivel table  34  is tipped in a corresponding fashion, such as tipping to the right when the rear driving platform  18  rotates clockwise, as viewed from the top. The main body  14  tips with the spindle table  34 . 
   With particular reference to  FIGS. 2 ,  3  and  5 , the swivel of the rear driving platform  18  is caused by a steering motor  42  that is attached to the main body  14 . Its swivel output shaft  44  is perpendicularly aligned with the main body  14  and generally downwardly projecting through a hole  46  and attached to a swivel pinion gear  48 . An arcing gear segment  50  presented about a front top portion of the rear driving platform  18  and radially aligned with the spindle table  34  meshes with the swivel pinion gear  48 . Thus, turning the swivel pinion gear  48  causes the rear driving platform  18  to swivel relative to the main body  14 . A gear train  51  formed by the combination is also clutched so when there is no electric load on the motor  42 , the gear train  51  can be moved freely to help center, requiring a soft spring to turn the motor  42  on the return travel. 
   A restoring force assists in returning the rear driving platform  18  to a straight-ahead alignment. In particular, two laterally aligned posts  52 ,  54  are formed on the main body  14  spaced forward of the recessed arc surface  38  and spaced on each side of the longitudinal axis of the main body  14 . Left and right centering arms  56 ,  58  respectively are pivotally received by the posts  52 ,  54  at their forward ends, extending backward on each lateral side of limit block  40  of the rear driving platform  18 . The centering arms  56 ,  58  are urged into contact with the limit block  40  by a centering spring  60  attached across rear ends of the centering arms  56 ,  58  and by a centering pillar  62  formed just forward and centered on the recessed arc surface  38  and projecting upwardly parallel to Axis A. The centering arms  56 ,  58  pass on each side of the center pillar  62 . Thus, each centering arm  56 ,  58  is prevented from rotating toward the opposite lateral side of the main body  14  past the centering pillar  60  while the other centering arm  56 ,  58  is forced outwardly by the limit block  40 , stretching the centering spring  60 , as shown in  FIGS. 6-9 . 
   Alternatively, this may be done with a torsion spring and stops that would eliminate the arms. The gear train may also be a controlled servo that would turn and center with electric input to the motor. The motor could be turned off and on with switches at the end of the travel and in the center position. 
   With particular reference to  FIG. 3 , the rear left and right dummy wheels  24 ,  26  are not load bearing but rather are attached to respective left and right trailing arms  64 ,  66  that are pivotally attached to the main body  14 . These rear dummy wheels  24 ,  26  obscure the rear drive wheels  28 ,  30  and the rear driving platform  18  to enhance the illusion of drifting. A respective forward pivoting end  68 ,  70  of each trailing arm  64 ,  66  is aligned with an Axis C that is laterally transverse to the plane of the main body  14  and is perpendicular to Axes A and B. Respective back ends  72 ,  74  of each trailing arm  64 ,  66  present a pin hole  80 ,  82  respectively aligned with an Axis D and Axis D′ that are parallel to Axis C. When the toy vehicle  10  is in its straight ahead condition (i.e., rear driving platform  18  not swiveled), the Axes D and D′ of the dummy rear wheels  24 ,  26  are the same and are horizontal. When the toy vehicle  10  turns, as in  FIG. 7 , the axes D and D′ are parallel but not equal since the trailing arms  64 ,  66  each pivot to maintain the dummy rear wheels  24 ,  26  in contact with the underlying surface and their forward pivoting ends  68 ,  70  lean as Axis C tips from the horizontal along with the main body  14 . 
   Returning to  FIGS. 1-3 , the drifting effect is enhanced by a castoring front portion  16  of the chassis  12 , allowing a change in the turn radius. A lateral front flange  84  is upwardly oriented and attached across a front edge  86  of the main body  14  and projecting upwardly to receive the front portion  16  through a horizontally and longitudinally aligned guide  88 . The front portion  16  of the chassis  12  includes a horizontal front deck  90  with a lateral back flange  92  upwardly oriented and across a rear edge  94  of the front deck  90 . A guide hole  96  in the lateral back flange  92  is registered to the guide  88  in the lateral front flange  84  to receive a pin  98 . The main body  14  tips left or right about the pin  98  as the front portion  16  remains horizontal with the front wheels  20 ,  22  remaining on the underlying surface. 
   The front wheels  20 ,  22  castor in unison by being coupled to the front portion  16  of the chassis  12  by a front steering assembly  100 . Left and right castoring wheel supports  102 ,  104  reside horizontally respectively along an inside diameter of each front wheel  20 , 22 . Left and right front axles  106 ,  108  respectively pass through each front wheel  20 ,  22  and midpoints of castoring wheel supports  102 ,  104  to pin the respective wheel  20 , 22  for rotation. A lower front plate  110  laterally crosses a front edge  112  of the horizontal front deck  90  of the front portion  16  of the chassis  12 . The lower front plate  110  extends laterally to each side to expose left and right tabs  114 ,  110 . A left front spindle  118  vertically spaces and rotationally attaches the left tab  114  to a front end  120  of the castoring left wheel support  102 . Similarly, a right front spindle  122  vertically spaces and rotationally attaches the right tab  116  to a front end  124  of the right castoring wheel support  104 . The front ends  120 ,  122  of the left and right castoring wheel supports  102 ,  104  are also laterally spaced and allowed to horizontally pivot to an upper front chassis plate  126 . 
   A steering link  128  is laterally aligned aft of and below the front upper chassis plate  126  for spacing rear ends  130 ,  132  respectively of the left and right castoring wheel supports  102 ,  104 . In particular, left and right rear spindles  134 ,  136  respectively vertically space and couple for horizontal rotation of each rear end  130 ,  132  above left and right lateral ends  138 ,  140  of the steering link  128 . Three vertical spacers  142 - 146  are laterally spaced and attached to the upper surface of the lower front plate  110  for providing a surface upon which the upper front chassis plate  126  and the steering link  128  may rest. 
   Power and control for the toy vehicle  10  are provided by a controller module  150  that is attached to the main body  14 , a battery box  152  is also attached to the main body  14  and engages a battery (or batteries)  154 . Inside the rear driving platform  18  is a drive motor  156 . With reference to  FIG. 10 , the control module (“Circuit Board”)  150  includes a remote control receiver  160  that is in electromagnetic communication with a remote control transmitter  162 , that is typically a detached portable device that accompanies the toy vehicle  10 . Commands for driving and/or turning are interpreted by a controller circuit  164  and transmitted respectively to the driving motor (“Rear Drive”)  156  and the steering motor  42 , each powered by the battery  154 . 
   In use, the remote control transmitter  162  transmits a command to the toy vehicle  10  to drive. The remote control receiver  160  receives the drive command, relays the drive command to the controller circuit  164 , which in turn activates the rear drive motor  156 . The rear drive platform  18  straightens under the influence of the centering arms  56 ,  58 , centering spring  60  and centering post  62  and turns the drive wheels  28 ,  30  to propel the vehicle  10 . When the remote control transmitter  162  transmits a turn command, the remote control receiver  160  and control circuit  164  command the steering motor  42  to swivel toward the command turn direction, thus rotating the main body  14  of the chassis  12  in the opposite direction, appearing to slide out of the turn (drift). Since the rear drive platform  18  is tipped slightly downward to its front, the rear drive platform tips the main body  14  to the opposite lateral side to the swivel of the rear drive platform  18 . Dummy rear wheels  24 ,  26  supported by trailing arms  70 ,  72  obscure the action of the rear drive platform  18 . Front wheels  20 ,  22  castor in the direction of movement of the toy vehicle  10  by a front steering assembly  95 , which is attached to a front portion  16  of the chassis  12  that does not tilt but instead is pivotally attached to the main body  14 . 
   While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. 
   For example, it should be appreciated that aspects of the present invention for drifting would apply to applications wherein a user control is directly wired to a control module, is a preprogrammed routine for the toy vehicle to perform, or is in response to sensed parameters (e.g., the toy vehicle follows markings or other indicators on the under surface). 
   As another example, instead of two rear drive wheels  28 ,  30 , one drive wheel may be used. The drive motor  156  may be capable of discrete or a continuous range of speeds, including forward and reverse. 
   As yet another example, some subset of the features of a swiveling, obscured rear driving platform: dummy rear wheels; a non vertical Axis A that induces a chassis to tilt when turning; and a horizontal, castoring front end may be used rather than all of these features in combination. 
   As yet an additional example, motorized vehicles that may be ridden by a child may advantageously incorporate mechanisms as described herein to create a drifting effect. Since such vehicles are generally not capable of going fast enough to actually drift, this effect may be particularly entertaining. 
   As yet a further example, while castoring the front wheels in combination with a selectively steered rear end successfully achieves drifting and controlled turns, an application consistent with the present invention may include steered front wheels, such as front wheels turning in a fixed relation to the angle of the swivel of the rear drive platform. Alternatively, steered front wheels may perform independently of the drifting ability. For example, an additional control or a determination made based on the commanded speed and degree of turn may cause the drifting mode to be enabled such that the rear drive platform is swiveled.