Abstract:
A modular vehicle system consisting of a rear propulsion device and a variety of different front-end assemblies that can be attached to the rear propulsion device to create different types of motorized vehicles. The rear propulsion device contains a frame, an engine mounted to that frame and a drive wheel that is driven by the engine. The front-end assemblies contain a frame, a steering fork element and a steering mechanism for turning the steering fork element. The steering fork supports either a front wheel or a ski. The frame of the front-end assembly attaches to the frame of the rear propulsion device in order to create a vehicle upon which a person can sit. At any time, the front-end assembly can be exchanged with another of a different configuration in order to change the physical characteristics of the resultant vehicle.

Description:
RELATED APPLICATIONS 
     This application is a Continuation-In-Part of U.S. patent application Ser. No. 09/455,512, filed Dec. 06, 1998, now abandoned entitled SYSTEM AND METHOD FOR PROPELLING A PERSON. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to low horsepower vehicular systems used to transport a single person. More particularly, the present invention relates to low horsepower vehicular systems that can be converted into different configurations for different purposes. 
     2. Description of the Prior Art 
     The first time man ever connected wheels to his shoes is long lost in history. Since that day, countless versions of skates, skateboards, scooters and like inventions have been developed that share the same basic idea. That idea being that it is fun and entertaining to propel yourself on a set of small wheels. 
     Since the very beginning of skates, people have sought ways to propel themselves on the skates, other than through physical exertion. For example, many a child has used the family dog to pull them on skates. Over the years, several people have developed motorized propelling systems that take the place of the family dog. Prior art motorized propelling systems typically have a wheel mounted to an elongated frame. The wheel is turned by a small gasoline engine. A person on skates is propelled by hanging on to the elongated shaft as the gasoline engine drives the motor. 
     Such prior art propelling systems come in two styles. In the first style, the motorized propelling system is positioned in front of a person and is used to tow that person. Such prior art devices are exemplified by U.S. Pat. No. 5,385,210 to Harvey, entitled Tow Vehicle System. Such systems are not very powerful because the weight of the person being pulled is not used to bias the drive wheel against the ground. Accordingly, when the ground is not smooth and level, such prior art devices tend to spin their wheels. Furthermore, since the person being propelled is being pulled, a person needs great strength in his arms to pull himself toward the motorized propelling system in order to maintain an upright position and maintain balance. Additionally, since the person using such a motorized device is being pulled, the motorized device is also used to steer. The skates on the person merely follow the direction of the motorized device. 
     Recognizing the disadvantages of motorized systems that pull a person, inventors have designed rear positioned propelling systems. In a rear propelling system, the motor and drive wheel are positioned behind the person being propelled. Consequently, the person is pushed by the propelling device. The weight of the person acts to bias the drive wheel against the ground. Accordingly, rear propelling systems have much better traction and power than do front propelling systems. Furthermore, the skates are now used to steer, since the skates are positioned in front of the rear propelling system. Examples of rear propelling systems can be found i in U.S. Pat. No. 4,456,089 to Kuwahara, U.S. Pat. No. 5,562,176 to Lucernoni and United Kingdom Patent Application GB 2246751 A to Kneale. 
     However, a disadvantage of the rear propelling system is that the frame of the propelling system extends between the legs of the person being propelled. Accordingly, a person using such a device is prevented from crossing his legs. This severely limits the movements of a person wearing in-line skates, wherein certain maneuvers require that a person cross his/her legs in order to successfully complete the maneuver. 
     Another problem with prior art propelling systems is that they only have a single configuration. As such, a person can only be propelled by such devices in a single manner. As such, some propelling devices only propel people who are wearing skates. Some prior art propelling devices only propel people who are on bicycles. However, prior art devices used for bicycle cannot be adapted for use by a person with skates and vice versa. 
     A need therefore exists for a rear motorized propelling system that can propel a person from the rear without extending through that person&#39;s legs or otherwise limiting the maneuverability of a person&#39;s legs. A need also exists for a rear motorized propelling system that is modular in construction and can be selectively reconfigured for different applications. These needs are met by the present invention as it is described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a modular vehicle system consisting of a rear propulsion device and a variety of different front-end assemblies that can be attached to the rear propulsion device to create different types of motorized vehicles. The rear propulsion device contains a frame, an engine mounted to that frame and a drive wheel that is driven by the engine. The front-end assemblies contain a frame, a steering fork element and a steering mechanism for turning the steering fork element. The steering fork supports either a front wheel or a ski. 
     The frame of the front-end assembly attaches to the frame of the rear propulsion device in order to create a vehicle upon which a person can sit. At any time, the front-end assembly can be exchanged with another of a different configuration in order to change the physical characteristics of the resultant vehicle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of exemplary embodiments thereof, considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of an exemplary embodiment of a rear propulsion device, shown in conjunction with a person wearing in-line skates; 
     FIG. 2 is top view of the embodiment shown in FIG. 1; 
     FIG. 3 is a side view of both a rear propulsion device and an exemplary cycle front-end subassembly; 
     FIG. 4 is a side view of the cycle front-end subassembly of FIG. 3 shown with a ski element substituted for the front wheel; and 
     FIG. 5 is a side view of both a rear propulsion device and an exemplary recumbent cycle front-end subassembly. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a first embodiment of the present invention propulsion assembly  10  is shown next to a person  12  wearing a pair of in-line skates. The propulsion assembly  10  includes a drive wheel  14  that rests upon the ground. It is the rotation of the drive wheel  14  that propels both the propulsion assembly  10  and the person  12  forward. The drive wheel  14  can be of any diameter. However, a diameter of between eight inches and twenty four inches is preferred. The use of a drive wheel is preferred on paved and earthen surfaces. However, when used in snow, it should be understood that a track, such as that used on a snowmobile, can be substituted for the drive wheel. 
     The drive wheel  14  is rotated by an engine. The engine can be an electric motor, a diesel engine, a propane engine or the like. However, in the preferred embodiment a gasoline engine  16  is used. Although any gasoline engine  16  can be used, the gasoline engine  16  is preferably a two stroke gasoline engine that is air cooled. The gasoline engine  16  can be electrically started. However, to eliminate the weight and cost of a starter motor and battery, the gasoline engine may alternately be started by manually pulling a pull cord. 
     Every state has regulations regarding gasoline powered vehicles with respect to the state registration of those vehicles. In most all states, registration is not required for vehicles with gasoline motors below a predetermined size and horsepower. It is preferable that the gasoline engine of the assembly be below the state requirements for registration. However, most any sized gasoline engine can be used. 
     In the shown embodiment of the assembly, the gasoline engine  16  has an engine displacement of approximately 40 cubic centimeters and a horsepower rating of about 1.5 horsepower. Such power ratings are typically below the registration requirements of most states and therefore do not require registration, inspection or insurance. 
     Both the drive wheel  14  and the gasoline engine  16  are connected to a common frame  18 . The drive wheel  14  is free rotating with respect to the frame  18  and the gasoline engine  16  is fixed to the frame  18 . The drive wheel  14  is interconnected to the gasoline engine  16  in one of a variety of different ways. The drive wheel  14  can be driven by a chain that is turned by the gasoline engine  16 . Alternately, the drive wheel  14  can be connected to the gasoline engine  16  with a direct gear drive, a belt drive or any other drive train system used in the prior art to connect a wheel to a gasoline engine. 
     The frame  18  also supports a small gas tank  20  that stores the gasoline used by the gasoline engine  16 . The size of the gas tank  20  is dependent upon the size and power of the gasoline engine  16 . The gas tank  20  preferably holds enough gasoline to power the gasoline engine  16  for at least one hour. 
     Two removable handle bars  22  extend from the frame  18 . The removable handle bars  22  selectively connect to the frame  18  at a common point on the frame  18 . However, once connected to the frame, the two handle bars  22  diverge away from each other as they extend from the frame  18 . As such, the handle bars  22  terminate at a predetermined distance D 1  apart from each other, wherein that predetermined distance D 1  is between eighteen inches and three feet. 
     At the ends of the removable handle bars  22  are lever controls  24 . The lever controls  24  engage control cables  25 . On one of the handle bars  22 , the lever control  24  controls the throttle of the gasoline engine  16 . On the second handle bar, the lever control controls the brake. 
     In between the handle bars  22  is positioned a removable support element  26 . It is the removable support element  26  that physically contacts a person and pushes a person when the assembly  10  is used. The removable support element  26  is preferably padded so as not to cause injury to a person when pressed against that person. Referring to FIG. 2, it can be seen that the removable support element  26  and the handle bars  22  define a generally U-shaped space  30 . When a person  12  is utilizing the assembly  10 , a person  12  stands within the U-shaped space  30 . As the drive wheel  14  turns, the propulsion assembly  10  presses the support element  26  against the body of the person  12 . The propulsion assembly  10 , therefore propels a person forward without interfering with a person&#39;s ability to move their legs or cross their legs. 
     The handle bars  22  of the propulsion assembly  10  are grasped by the person using the propulsion assembly  10 . The points where a person grasps the handle bars  22  are similar to the position in which a person would hold ski poles. A person can therefore turn the propulsion assembly  10  by pushing, pulling and tilting the handle bars  22 . Accordingly, a person can angle the propulsion assembly  10  or cause the propulsion assembly  10  to contact the back of the person at different angles. This provides great agility and steerability to the propulsion assembly  10  that is unavailable in the prior art. 
     Returning to FIG. 1, it can be seen that a removable secondary support element  32  extends from the frame  18  to the center of the first support element  26 . The secondary support element  32  may contact a person&#39;s back if a person holds the propulsion assembly  10  at a particularly steep angle of inclination. Since the secondary support element  32  may contact the person using the propulsion assembly  10 , the secondary support element  32  is also preferably padded. 
     When a person utilizes the propulsion assembly  10 , they stand in between the handle bars  22 . Once the throttle on the handle bar  22  is activated, the gasoline engine  16  powers the drive wheel  14 . The turning of the drive wheel  14  propels the propulsion assembly  10  forward and biases the propulsion assembly  10  against the back of the person  12 . Depending upon the angle at which the propulsion assembly  10  is held, either the support element  26  contacts the back of the person  12  or both the support element  26  and the secondary support element  32  contact the person  12 . As the propulsion assembly  10  biases the support element  26  against the back of the person  12 , the person  12  is propelled forward. 
     People on skates, skateboards, skis and the like often fall. To prevent the propulsion device from accidentally running over a fallen person, the propulsion device comes with a safety shut off. The safety shut off is a kill switch that automatically stops the gasoline engine  16 . The kill switch is activated when a tethered clip  34  is pulled from a connector port on the propulsion assembly  10 . The tethered clip  34  attaches to a person utilizing the propulsion assembly  10 . Consequently, if a person falls while using the propulsion assembly  10 , the tethered clip  34  will be pulled from the assembly and the gasoline engine  16  will automatically stop. 
     The present invention propulsion assembly  10  also comes with a retractable tow cord  36 . The tow cord  36  is attached to the rear of the frame  18 . The tow cord  36  can be held by another skater, skier, skateboarder or the like, thereby enabling the propulsion device  10  to simultaneously propel at least two different individuals. 
     Referring to FIG. 3, an alternate embodiment of the present invention assembly  40  is shown. In this embodiment, the handle bars  22  (FIG.  1 ), first support element  26  (FIG. 1) and second support element  32  (FIG. 1) of the previously described propulsion device  10  are removed from the front of the frame  18 . A cycle front-end subassembly  42  is then attached to the frame  18 , thereby creating a motorized two-wheel cycle assembly. 
     The cycle front-end subassembly  42  contains a secondary frame  44  that attaches to the primary frame  18  of the propulsion device  10  using mechanical fasteners, such as pins, bolts or the like. The secondary frame  44  of the cycle front-end subassembly supports a foot platform  46 , a seat  48 , a set of cycle handle bars  50  and a front fork element  52 . A front wheel  54  mounts to the front fork element, thereby providing the overall assembly with two wheels. 
     Once the cycle front-end subassembly  42  is mounted to the frame  18  of the propulsion device  10 , a motor scooter is created. A person can sit on the seat  48  and place his/her feet on the foot platform  46 . The motor scooter is steered by moving the handle bars  50 . The control cables  25  extending from the gasoline engine  16  are attached to control levers  56  on the handle bars  50 . As such, a person riding the motor scooter can control the operations of the engine from the handle bars  50 . 
     Referring to FIG. 4, it can be seen that the front wheel  54  (FIG. 3) of the cycle front-end subassembly  42  can be replaced with a ski  60 . The ski  60  mounts to the front fork element of the cycle front-end subassembly in place and stead of the previously described wheel. In this configuration, the overall assembly is configured to ride on snow, wherein the front ski  60  is used to steer through the snow. 
     In the embodiments of FIG.  3  and FIG. 4, the seat is positioned in the middle of the overall assembly. This seat position enables a person to sit upright and hold onto the handle bars to steer. Referring now to FIG. 5, an alternate embodiment of the present invention is shown. In this embodiment a recumbent cycle front-end subassembly  70  is shown. The recumbent cycle front-end subassembly  70  has a frame  72  that also selectively attaches to the frame  18  of the original propulsion device  10 . The frame  72  of the recumbent cycle front-end subassembly  70  supports a seat  74  above the propulsion device  10  between the engine  16  and the rear drive wheel  14 . The frame  72  of the recumbent cycle front-end subassembly  70  also supports a fork element  76  in front of the propulsion device  10 . Foot supports  78  extend horizontally from opposite sides of the fork element  76 . When a person sits on the seat  74 , that person&#39;s feet rest upon the foot supports  78 . By pressing the foot supports  78  with a person&#39;s feet, the orientation of the fork element  76  can be changed. Thus a person can use his/her feet to steer the overall assembly. 
     The fork element  76  supports either a front wheel  80  (shown) or a front ski (not shown), depending upon the intended terrain. 
     In the embodiment of FIG. 5, a person sitting in the assembly must be able to control the engine  16  and the brakes of the recumbent vehicle. For this purpose, two handle bars  82  can be mounted to the assembly so that the handle bars  82  extend on either side of the seat  74 . On the handle bars  82  are positioned the control levers  84  that are used to control the engine and brakes. 
     It will be understood that the embodiments of the present invention system described and illustrated herein are merely exemplary and a person skilled in the art can make many variations to the embodiment shown without departing from the scope of the present invention. For example, the prior art is replete with different types of gasoline engines, transmissions and braking systems. Any such prior art devices can be adapted for use in the present invention. All such variations, modifications and alternate embodiments are intended to be included within the scope of the present invention as defined by the appended claims.