Abstract:
An energy efficient tricycle has a frame, fork and handlebars connected to hold a front wheel and two rear wheels. A power and transmission assembly means is mounted on the frame to provide power to both rear wheels. A pair of pedals are independently operable and used to provide the torque needed to propel the tricycle. A motorized embodiment is also provided to provide additional power when needed or to completely motorize the tricycle. The pedals are mounted so that they travel in a vertical path. The handlebars, front wheel and both rear wheels are foldable to allow the tricycle to fit within a vehicle. The tricycle has a very low center of gravity. A seat is provided in one embodiment to allow a user to sit and operate using a motor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority and herein incorporates by reference U.S. provisional patent application 61/242,057, filed Sep. 14, 2009. 
    
    
     BACKGROUND OF THE INVENTION 
     Throughout the world, bicycle production and use still outnumbers automobile production and use almost two to one. Bicycles have the advantage of not requiring fuel or at least very little for the powered versions compared to automobiles. Additionally, maintenance is much more accessible and allows even relatively poor users to keep their bicycle operational. 
     Of course some of the advantages of bicycle are also a detriment to their use. They require much more human effort to use and they are less comfortable in general than some other forms of transportation. Additionally, bicycles are inherently unstable unless in motion. Tricycles use three wheels and obviate this problem by stabilizing the tricycle without relying on gyroscopic principles. Tricycles generally provide more space to carry things and for more comfortable seating than most bicycles. 
     Tricycles gain stability at the expense of steering control because unlike a bicycle which leans in a turn, tricycles generally rely on turning the front wheel which is less maneuverable. 
     There is a need for a stable tricycle that provides maneuverability, ease of use and economy in operating costs that overcomes the shortcomings of the prior art. 
     SUMMARY OF THE INVENTION 
     An energy efficient tricycle has a frame, fork and handlebars connected to hold a front wheel and two rear wheels. A power and transmission assembly means is mounted on the frame to provide power to both rear wheels. A pair of pedals are independently operable and used to provide the torque needed to propel the tricycle. A motorized embodiment is also provided to provide additional power when needed or to completely motorize the tricycle. The pedals are mounted so that they travel in a vertical path. The handlebars, front wheel and both rear wheels are foldable to allow the tricycle to fit within a vehicle. The tricycle has a very low center of gravity. A seat is provided in one embodiment to allow a user to sit and operate using a motor. 
     Other features and advantages of the instant invention will become apparent from the following description of the invention which refers to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an energy efficient tricycle according to an embodiment of the invention. 
         FIG. 2  is a front view of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 3  is back view of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 4  is a top view of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 5  is a top view showing the front wheel in a folded position of the of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 6  is a side view showing the steering tube in a folded position of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 7  is a side view showing the steering tube and front wheel in the folded position. 
         FIG. 8  is a side view showing the steering tube, front wheel and both rear wheels in the folded position. 
         FIG. 9  is an energy efficient tricycle having a seat according to an embodiment of the invention. 
         FIG. 10  is an energy efficient tricycle having a battery. 
         FIG. 11  is an energy efficient tricycle having a motor. 
         FIG. 12  is a top view of the energy efficient tricycle shown in  FIG. 10 . 
         FIG. 13  is a detailed cut-away view of a portion of the energy efficient tricycle shown in  FIG. 1 . 
         FIG. 14  is a cut-away view of the transmission of the energy efficient tricycle shown in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the invention, reference is made to the drawings in which reference numerals refer to like elements, and which are intended to show by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and that structural changes may be made without departing from the scope and spirit of the invention. 
     Referring to  FIGS. 1 through 4 , an energy efficient tricycle  100  is shown having a frame  120 . Frame  120  is lightweight and strong. It is made of a high carbon steel such as chromoly, aluminum or even a carbon fiber composite as long as the frame remains strong yet flexible. A handlebar  115  telescopically fits within a steering tube  144 . A clamp  106  selectively secures handlebars within steering tube  144 . A front wheel  114  is secured with fork  148  which is rotatably attached to steering tube  144 . 
     A front axle  124  is attached to fork  148  and allows wheel  114  to roll. A front hand brake  154  is provided to control front wheel  114 . Handlebar  115  has two handgrips  102  and hand brakes  104 . Brake cables  110  and  112  are secured using brake ties  108 . In order to allow tricycle  100  to be easily transported and stored, a handlebar folding hinge  116  is provided and will be discussed in detail later. A rotating hinge lock  146  is provided to lock steering tube  144  in place during use and then to easily move into a storage position. A front wheel rotating hinge  118  is provided for folding as well. Two foot pedals  122  are provided to allow a user to apply a locomotive force. Each pedal  122  is independently operable and need not be in any special position to operate. 
     A cover  126  is provided to cover and protect the transmission, electronics and battery if so equipped. The downward force from pedals  122  is transmitted to the rear wheels  140  using a main drive chain  128 . Of course, a belt or other force transmitting mechanism could be used as long as the downward force is able to be turned into a torque to turn the wheels  140 . Two rear drive sprockets—one on each side  130  are provided to transmit the torque to the wheels  140 . In operation, energy efficient tricycle  100  is able to operate over varying terrains by adjusting the height of the rear wheels  140  using an adjustment  132 . A series of holes allow a user to select the desired height. A pin, or other detent fits within the hole to maintain the selected height. 
     Each rear wheel  140  is supported by a rear wheel support frame  134  is used both for structural purposes as well as providing the axle to support the wheels. This configuration allows the end portion of tricycle to be open and completely accessible. Because of this, a platform  142  is provided to allow easy access. The user can merely step on platform  142  and is ready to go. 
     To provide superior braking performance, disc brakes are provided on rear wheels  140 . The disc brakes consist of a rotor  136  and caliper  138  for each rear wheel  140 . Two rear wheel drive chains  150  are provided to transmit the torque from pedals  122  and main drive chain  128 . To further enhance the foldability of tricycle  100 , two rear wheel rotating bushing  152  are provided. During operation, rear wheel support frames  134  are securely held in place by rear wheel clamps  170 . When released, rear wheels  140  may be rotated to a compact position. 
     Pedals  122  are rotatably attached to frame  120  using pedal arms  156  using a bearing or bushing  158 . Also provided are two recoil pistons  160  which bias pedals  122  to an operable position and will be discussed in detail below. 
     Now referring to  FIGS. 5 through 8 , energy efficient tricycle  100  is able to fold for transportation and storage. Handlebar  115  telescopically slides down within steering tube  144  by loosening telescopic clamp  106  ( FIG. 1 ) and then sliding al the way down and then retightening. Next handlebar rotating hinge is release and steering tube  144  folds down until it rests on front tire  114 . 
     Now front wheel rotating hinge lock  146  is released and this allows front wheel assembly (wheel  114 , fork  148 , brake  154  and steering tube  144 ) to rotate around 180 degrees so that front wheel  114  is now facing an opposite direction and is alongside cover  126 . 
     Next, rear wheel clamps  170  are released and rotated towards the front. In this configuration, tricycle  100  is in a very compact configuration which allows a user to easily carry and transport. It easily fits within a truck of a car, etc. To operate, the procedure is reversed. 
     Now referring to  FIG. 9 , a seat  174  is provided to allow a user to sit down while operating in a motorized embodiment. Seat  174  is cushioned by riding on a spring shock absorber  176  to absorb bumps and road conditions. Seat  174  may be adjusted forwards and backwards using seat adjustment  178 . Additionally, a height adjustment may be provided (not shown). 
     Referring now to  FIGS. 10 ,  11  and  12 , two direct drive motors  180  are provided to allow a user to have a motorized assist while operating. A battery  168  is used to provide energy to direct drive motors  180 . In this embodiment, the operator may still pedal and have the motors  180  automatically assist during given load situations such as going up hills, speed falls below a selected level or in a completely motorized mode where the pedals are not used or are only used to control the speed. Of course a throttle (not shown) may also be provided which can be mounted on hand grips  102  as is known in the art. In the motorized embodiment or even in a pedal mode if coasting, leg support  172  are provided to allow a user to rest against pedals  122  while standing on platform  142 . Leg supports  172  are made of a resilient material such as foam or rubber to absorb vibration and provide a comfortable support while operating in a standing position. 
     Now referring to  FIGS. 13 and 14 , half of the transmission is shown. Since there are two pedals  122 , the other half if the transmission is mirrored and not shown in the figures. Pedal arm  156  is rotatably anchored around a pedal arm pivot  190 . Recoil piston  160  is attached to the base of cover  126  and attached to the end of pedal arm. An eccentric gear  186  is rotatably secured to the inside of cover  126  and a recoil cord  192  is attached therein. The other end of recoil cord  192  feeds around a recoil pulley and then a pulley located within pedal arm  156  and secured to cover  126  using a hold down  196 . In this way, as pedal arm  156  rotates down the acceleration is get relatively constant due to the eccentricity of pulley  186 . A main shaft gear  188  is centrally located to mechanically communicate with main drive chain  128  which is connected to main drive gear  166  which transmits torque to rear drive chains  150 . 
     Now referring to  FIG. 12 , a sensor  184  is provided on main shaft along main drive gear  166 . A sensor disk  182  has magnets or holes or both so that sensor  184  can detect rotational speed and acceleration which can be transmitted to a central processing unit (not shown) as is know in the art. In this embodiment, the CPU can automatically assist the user to add power to help even when pedaling. This option is especially helpful to users who want the benefit of exercise but may not have the stamina to rely solely on muscle power. 
     The energy efficient tricycle has a completely open end due the fact that the rear axle is part of the structural support rather than just a axle alone and this allows the user easy access from the back. The instant invention is designed to be operated while standing (except for the seated embodiment) and this is good for exercise, posture and visibility. The center gravity of the instant invention is very low which leads to a very stable ride. Even novice users will feel confident while operating. Unlike standard bicycles and tricycles, each pedal is independent and can be operated using only one pedal if desired. This would allow some disabled users to operate. The height of the tricycle can be adjusted which is extremely useful by allowing a user to adjust for grass, smooth road, etc. 
     Although the instant invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.