Abstract:
A vehicle incorporating a power unit having a front portion, a rear portion and a power source. A drive wheel, disposed in the front of the power unit, is connected to the power source. A brake pad is connected to the power unit beneath the power source and a handle bar extends back from the power unit. The vehicle includes a trailer unit, disposed behind the power unit, having two trailer wheels, disposed on opposite sides of the trailer unit. A connecting joint, connecting the power unit to the trailer unit, allows the power unit and trailer unit to move with respect to one another about the horizontal pitch axis and/or vertical yaw axis.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to motorized vehicles, and more specifically to a motorized vehicle having a separate power unit and trailer unit. 
   BACKGROUND OF THE INVENTION 
   A variety of wheeled vehicles are known. Three-wheeled powered vehicles are not new. A number of designs and configurations of wheeled vehicles have been developed for use in a broad range of applications. Certain such designs have a unitary construction, while other designs have used a construction having more than one segment, wherein the multiple segments are articulated to one another through some form of joint or joints. 
   Although certain three-wheeled vehicles have been developed, each of the prior designs incorporates one or more limitations tending to restrict its use in certain applications. In certain designs, such vehicles are insufficiently maneuverable. In certain other designs, such vehicles are unstable and difficult to control. There remains in the field a need for a wheeled vehicle having sufficient maneuverability as well as sufficient stability. 
   SUMMARY OF THE INVENTION 
   In one embodiment, the present invention is a vehicle incorporating a power unit having a drive wheel connected to a power source, a trailer unit having at least one trailer wheel, and a connecting joint, connecting the power unit to the trailer unit, allowing the power unit and trailer unit to move with respect to one another about at least one axis. 
   In a second embodiment, the present invention is a vehicle incorporating a power unit having a front portion and a rear portion. A drive wheel, disposed in the front of the power unit, is connected to a power source. A handle bar extends back from the power unit for steering of the vehicle. This embodiment further includes a trailer unit, having two or more trailer wheels, disposed behind the power unit. Finally, the vehicle incorporates a connecting joint, connecting the power unit to the trailer unit, allowing the power unit and trailer unit to move with respect to one another about two axes. 
   In a third embodiment, the present invention is a vehicle including a power unit having a front portion, a rear portion, a power source, and a drive wheel disposed in the front portion of the power unit and connected to the power source. This embodiment incorporates a brake pad, connected to the power unit beneath the power source and a handle bar extending back from the power unit. A trailer unit is disposed behind the power unit, having two trailer wheels, disposed on opposite sides of the trailer unit. A connecting joint, connecting the power unit to the trailer unit, allows the power unit and trailer unit to move with respect to one another about the horizontal pitch axis and vertical yaw axis. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which: 
       FIG. 1  is an isometric view of a motorized chariot in accordance with one embodiment of the present invention; 
       FIG. 2  is an isometric view of a motorized chariot in accordance with one embodiment of the present invention; 
       FIG. 3  is a side view of the motorized chariot of  FIGS. 1 and 2 ; 
       FIG. 4  is a side view of the motorized chariot of  FIGS. 1 and 2 ; 
       FIG. 5  is a side view of the motorized chariot of  FIGS. 1 and 2 ; 
       FIG. 6  is a top view of the motorized chariot of  FIGS. 1-5 ; 
       FIG. 7  depicts an exploded isometric view of the anterior portion of the power unit and the trailer unit of the motorized chariot; 
       FIG. 8  depicts a detailed exploded isometric view of the connection joining the power unit to the trailer unit of the motorized chariot; 
       FIG. 9  depicts a second detailed exploded isometric view of the connection joining the power unit to the trailer unit of the motorized chariot; 
       FIG. 10  is a side view of the pitch/yaw joint of  FIGS. 7-9 ; 
       FIG. 11  is a top view of the pitch/yaw joint of  FIG. 10 ; 
       FIG. 12  is a rear view of the pitch/yaw joint of  FIGS. 7-11 ; 
       FIG. 13  is a side view of the pitch/yaw joint of  FIGS. 7-12  showing the pitching of the pitch/yaw joint; 
       FIG. 14  is a side view of the pitch/yaw joint of  FIGS. 7-12  showing the pitching of the pitch/yaw joint; 
       FIG. 15  is a side view of a motorized chariot employing an electric motor for a mechanical power source; and 
       FIG. 16  is a detailed side view of the motorized chariot of FIG.  15 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention. 
     FIGS. 1 and 2  are isometric views of a motorized chariot  100  in accordance with one embodiment of the present invention.  FIGS. 3 ,  4  and  5  are side views of the motorized chariot  100  of  FIGS. 1 and 2 .  FIG. 6  is a top view of the motorized chariot  100  of  FIGS. 1-5 . 
   As seen in  FIGS. 1-6 , motorized chariot  100  incorporates a power unit  102  disposed ahead of, and connected to, a trailer unit  104 , so as to pull trailer unit  104 . Power unit  102  and trailer unit  104  are built around a power unit frame  106  and trailer unit frame  108 , respectively. The direction of travel of motorized chariot  100  is controlled by manipulation of the handle bar  110 , which is directly connected to drive wheel  112  through a rigid mechanical connection. Drive wheel  112  also supports the front of the motorized chariot  100  and transmits motivating power to the ground. The rear of the motorized chariot  100  is supported by a pair of trailer wheels  114 . Steering of the motorized chariot  100  is generally performed by a human user (not shown) disposed in or upon the trailer unit  104  between the trailer wheels  114 . 
   Motivating power for the motorized chariot  100  is generated by an engine  116 . The motor  116  shown in  FIGS. 1 and 2  is a carbureted small-displacement single-cylinder four-stroke internal combustion engine similar to the type used on lawnmowers and other small powered equipment. Those of skill in the art will appreciate that nothing in the nature of the present invention limits its scope to this type of powerplant. 
   Mechanical power is transmitted out of the engine  116  to a clutch  118  disposed on the side thereof. Clutch  118  is designed to disengage and freewheel at low engine speeds, so as to allow the engine  116  to idle when the motorized chariot  100  is stationary. Clutch  118  may be a basic centrifugal clutch, or it may be a more-sophisticated variable ratio clutch of the type commonly used on snowmobiles and other small powered vehicles. Rotary mechanical power is transmitted from the clutch  118  to the primary chain  120 . Primary chain  120  may, in an alternate embodiment, be replaced with a power-transmission belt. 
   Primary chain  120  transmits mechanical power into the jack shaft  122 . Jack shaft  122  can, depending on the particular embodiment, be used as a speed reduction mechanism. Jack shaft  122  will act in this manner to increase the mechanical advantage of the engine  116  on the drive wheel  112  whenever the input sprocket  121  has a larger diameter than the output sprocket  123 . With this arrangement, the linear speed of primary chain  120  will be, by necessity, higher than the linear speed of the secondary chain  124  in a ratio equal to the ratio of the diameter of the input sprocket  121  to the diameter output sprocket  123 . 
   Power transmitted into the secondary chain  124  is then transmitted into the drive wheel sprocket  125 , which is rigidly attached to the drive wheel  112 . A speed reduction and torque multiplication may be designed into this portion of the power transmission mechanism as well, by providing a drive wheel sprocket  125  having a larger diameter than that of the jack shaft output sprocket  123 . In this case, the rotational velocity of the drive wheel sprocket  125 , and therefore the drive wheel  112 , is related to the rotational velocity of the jack shaft output sprocket  123  in inverse proportion to the ratio of the diameter of the drive wheel sprocket  125  to the diameter of the jack shaft output sprocket  123 . 
   As noted above, the motorized chariot  100  is designed to be driven by a human driver (not shown) disposed on the trailer unit  104 , and specifically on the trailer platform  126 , between the trailer wheels  114 . From this position, a human user can steer the direction of travel of the motorized chariot  100  using the handle bar  110 . A driver can control the speed of the motorized chariot  100  using the throttle control  128 , which is connected to the engine  116  by throttle cable  130 . In certain embodiments, throttle cable  130  may be connected directly to the butterfly valve (not shown) on the carburetor of engine  116 . In alternate embodiments, the throttle cable  130  may be connected to the butterfly valve indirectly through an engine speed governor. 
   In addition to its guidance and steering function, handle bar  110  incorporates an additional functionality not readily apparent from a cursory viewing of the motorized chariot  100 . In order for motorized chariot  100  to be steerable, the orientation of power unit  102  is variable with respect to trailer unit  104 . Accordingly, the connection between power unit  102  and trailer unit  104  is pivotable about the vertical axis, as described in more detail below. 
   What is not readily apparent from a cursory viewing of the motorized chariot  100  is that the connection between power unit  102  and trailer unit  104  is pivotable about a horizontal axis. If the motorized chariot  100  is not supported about this horizontal pivot, it will “collapse” under its own weight. At rest, without any force acting to support the motorized chariot  100  about this connection, the motorized chariot will come to rest on the brake pad  132  rigidly attached to the anterior portion of the power unit  102 . 
   In order to allow the motorized chariot  100  to move without dragging brake pad  132  on the ground, it is, of course, necessary to raise the brake pad  132  some distance off the ground. This is accomplished by the driver applying an upward force on the handle bar  110 , and therefore a moment about the power unit  102 , tending to lift the anterior portion of power unit  102 , and therefore the brake pad  132 , off the ground. Conversely, if the driver wishes to slow or stop the motorized chariot  100 , a downward force can be applied to the handle bar  110 . 
   A downward force on the handle bar applies a moment to the power unit  102  tending to force the anterior portion of the power unit  102  toward the ground and to lift the drive wheel  112  away from the ground. This manner of stopping can be most advantageous in the event of a stuck throttle or otherwise uncontrolled engine, in that the drive wheel  112  can be completely separated from contact with the ground. Further, this manner of stopping is advantageous in that the driver can apply the driver&#39;s full weight on the handle bar  110  in order to stop the vehicle in an emergency. 
     FIG. 7  depicts an exploded isometric view of the anterior portion of the power unit  102  and the trailer unit  104 .  FIGS. 8 and 9  depict detailed exploded isometric views of the connection joining the power unit  102  to the trailer unit  104 .  FIG. 10  is a side view of the pitch/yaw joint  154  of  FIGS. 7-9 .  FIG. 11  is a top view of the pitch/yaw joint of FIG.  10 .  FIG. 12  is a front view of the pitch/yaw joint  154  of  FIGS. 7-11 .  FIGS. 13 and 14  are side views of the pitch/yaw joint  154  of  FIGS. 7-12  showing the pitching of the pitch/yaw joint  154 . 
   As seen in  FIG. 7 , the anterior portion of power unit frame  106  incorporates a pair of frame rails  150  and  152 , which are joined together at their distal ends by pitch/yaw joint  154 , disposed between them, and motor plate  156 , disposed above them. As seen in  FIGS. 7-14 , pitching motion between the power unit  102  and the trailer unit  104  is accommodated by pitch/yaw joint  154  about pitch axle  158 . Similarly, yawing motion between the power unit  102  and the trailer unit  104  is accommodated by the pitch/yaw joint about yaw axle  160 , disposed orthogonally to pitch axle  158 . 
   The details of pitch/yaw joint  154  can be most clearly seen in  FIGS. 8-14 . Pitch/yaw joint  154  incorporates a right angle member  220 , a left angle member  222 , and a bracing member  224  tying right angle member  220  to left angle member  222 . The right angle member  220  and left angle member  222  incorporate pitch bores  226  and  228 , respectively. Pitch bores  226  and  228  accommodate and capture bearing ends  230  and  232 , respectively, of pitch axle  158 , thereby securing pitch axle  158  while allowing free rotation about the pitch axis. Pitch axle  158  is retained in place by a washer  234  and cotter pin  236 . 
   As noted, yaw axle  160  is disposed orthogonally to pitch axle  158 . As assembled, yaw axle  160  is disposed within a generally-cylindrical bore  161  of a generally-cylindrical yaw housing  162  and retained therein by the combination of a washer  164  and a cotter pin  166 . Other retention methods will be known to those of skill in the art and may be employed without departing from the spirit and scope of the present invention. 
   Yaw housing  162  is rigidly connected to a tailshaft  168 , which is shaped to mate with the tongue  170  of the trailer unit frame  108 . Tailshaft  168  is retained within the tongue  170  by a linch pin  172 , which is, in turn, retained by a cotter pin  174 . 
   With the above-described mechanism, using the combination of a pitch axle  158  and a separate yaw axle  160  orthogonal to one another, pitching and yawing motions can be fully accommodated between the power unit  102  and trailer unit  104 . At the same time, however, this mechanism does not provide for rolling motion of the trailer unit  104  with respect to the power unit  102 . Although other embodiments may incorporate the ability to accommodate rolling motion between the trailer unit  104  and power unit  102 , it is believed that prevention of rolling motion may provide certain advantages in the form of better control of the motorized chariot  100 . 
   Disposed at the outer ends of the trailer unit frame  108  are a pair of axles  176  and  196 . On the interior sides of the axles  176  and  196  are a pair of thrust washers  178  and  198 . Adjacent to thrust washers  178  and  198  axe a pair of thrust bushings  180  and  200 , and radial bearings  182  and  202 . Riding on bearings  182  and  202  are a pair of hubs  184  and  204 , upon which are disposed tires  186  and  206 . Securing hubs  184  and  204  on the outside are thrust bushings  188  and  208 , thrust washers  190  and  210 , and cotter pins  192  and  212 . 
     FIGS. 15 and 16  are side views of a motorized chariot  300  in accordance with a second embodiment of the present invention. As seen in  FIGS. 15 and 16 , motorized chariot  300  incorporates a power unit  302  disposed ahead of, and connected to, a trailer unit  304 , so as to pull trailer unit  304 . Power unit  302  and trailer unit  304  are built around a power unit frame  306  and trailer unit frame  308 , respectively. The direction of travel of motorized chariot  300  is controlled by manipulation of the handle bar  310 , which is directly connected to drive wheel  312  through a rigid mechanical connection. Drive wheel  312  also supports the front of the motorized chariot  300  and transmits motivating power to the ground. The rear of the motorized chariot  300  is supported by a pair of trailer wheels  314 . Steering of the motorized chariot  300  is generally performed by a human user (not shown) disposed in or upon the trailer unit  304  between the trailer wheels  314 . 
   Motivating power for the motorized chariot  300  is generated by an electric motor  316 . The motor  316  shown in  FIGS. 15 and 16  may be, for example, a, direct current motor, a brushless motor, a stepper motor, an alternating current motor. Those of skill in the art will appreciate that nothing in the nature of the present invention necessarily limits its scope to these specific types of electric motor. 
   Mechanical power is transmitted out of the electric motor  316  to a flywheel  318  disposed on the side thereof. Rotary mechanical power is transmitted from the flywheel  318  to the primary chain  320 . Primary chain  320  may, in an alternate embodiment, be replaced with a power-transmission belt. 
   Primary chain  320  transmits mechanical power into the jack shaft  322 . Jack shaft  322  can, depending on the particular embodiment, be used as a speed reduction mechanism. Jack shaft  322  will act in this manner to increase the mechanical advantage of the engine  316  on the drive wheel  312  whenever the input sprocket  321  has a larger diameter than the output sprocket (not shown). With this arrangement, the linear speed of primary chain  320  will be, by necessity, higher than the linear speed of the secondary chain  324  in a ratio equal to the ratio of the diameter of the input sprocket  321  to the, diameter of the output sprocket. 
   Power transmitted into the secondary chain  324  is then transmitted into the drive wheel sprocket  325 , which is rigidly attached to the drive wheel  312 . A speed reduction and torque multiplication may be designed into this portion of the power transmission mechanism as well, by providing a drive wheel sprocket  325  having a larger diameter than that of the jack shaft output sprocket. In this case, the rotational velocity of the drive wheel sprocket, and therefore the drive wheel  312 , is related to the rotational velocity of the jack shaft output sprocket in inverse proportion to the ratio of the diameter of the drive wheel sprocket  325  to the diameter of the jack shaft output sprocket. 
   As noted above, the motorized chariot  300  is designed to be driven by a human driver (not shown) disposed on the trailer unit  304 , and specifically on the trailer platform  326 , between the trailer wheels  314 . From this position, a human user can steer the direction of travel of the motorized chariot  300  using the handle bar  310 . A driver can control the speed of the motorized chariot  300  using the motor speed control  328 , which is connected to the motor  316  by control cable  330 . 
   In the embodiment shown in  FIGS. 15 and 16 , motor  316  receives electric power from a motor control module  340 , which regulates the flow of electricity from batteries  342  to electric motor  316 . Depending on the application, motor control module  340  may regulate the voltage to the motor  316 , the current to the motor  316 , or both. Motor  316  may incorporate a torque or speed feedback mechanism to the user, to the motor control module  340 , or both. Feedback to the motor control module  340  enables the power unit  302  to function as a servo, and thereby able to maintain a constant vehicle speed under a variety of conditions. 
   In order for motorized chariot  300  to be steerable, the orientation of power unit  302  is variable with respect to trailer unit  304 . Accordingly, the connection between power unit  302  and trailer unit  304  pivotable about the vertical axis, as described above. 
   Although preferred embodiments of the invention have been described in detail, it will be understood by those skilled in the art that various modifications can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.